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Jane Magee
September 11 1997
Ms J Lyn CutlerSection Chief Special ProjectsBureau of Waste Site CleanupDepartment of Environmental Protection436 Dwight StreetSpringfield MA 01103
Mr Bryan OlsonU S Environmental Protection AgencyOffice of Site Remediation and RestorationJF Kennedy Federal BuildingHRR-CAN3Boston MA 02203
Re DEP 11-0147P EPA Area 6Housatonic River Human Health Risk Assessment
Dear Ms Cutler and Mr Olson
By this letter the General Electric Company (GE) is providing a proposal regardingcertain input parameter values for the human health risk assessment of the Housatonic Riversite as well as a proposed schedule for submitting the deliverables required to complete therisk assessment These proposals are provided in accordance with the final comments of theDEP and EPA (the Agencies) on GEs February 1996 Proposal for Human Health RiskAssessment of the Housatonic River and the Agencies cover letter to those comments datedAugust 13 1997
The Agencies comments stated with respect to three input parameters that if GEdecides to provide an alternative value to the values specified in the comments GE mastsubmit that proposal within 30 days of receiving the Agencies comments Those parametersare (1) a Reference Dose for developmental effects of PCBs (Comment 10) (2) anenhanced soil ingestion rate for an adult former (Comment 56) and (3) a dermal absorptionfactor for PCBs (Comment 62) GEs proposal of alternative values for these parameters ispresented in Attachment A
The Agencies August 13 1997 cover letter directed GE to submit within 30 days aproposed schedule for submission of the specific deliverables required for completion of the sectrisk assessment in accordance with the revised approach outlined in the Agencies comments IjijjjjThat letter noted among other things that GE should derive and submit a risk-based jjjjconcentration (cleanup goal) for the residential scenario before developing risk-based
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concentrations for other exposure scenarios It also indicated that GE could propose to complete the risk-based concentrations and apply them to the site based on current uses prior to conducting the mapping exercise to identify foreseeable future uses and applying the risk-based concentrations to the site based on such future uses Considering that advice as well as the steps outlined in GEs February 1996 Proposal as modified by the Agencies comments of August 13 1997 GE has developed a proposed schedule for submission of the necessary risk assessment deliverable) That proposed schedule along with explanatory notes is set forth in Attachment B
This schedule of activities would begin upon receipt of the Agencies response to the proposal in Attachment A as well as approval of the proposed schedule in Attachment B In the meantime however we would like to discuss these proposals with you Please call me to schedule a time for such a discussion or if you have any questions about this matter
Very truly yours
Jane Magee Manager PittsfieldHousatonic
Remediation Programs
Attachments
cc Mary Holland DEP Alan Weinberg DEP Robert Bell Esq DEP Ralph Child Esq DEP Margaret Harvey DEP Matthew Hoagland EPA Douglas J Luckerman Esq EPA Charles Fredette Conn DEP Mayor Edward Reilly City of Pittsfield Pittsfield Commissioner of Health Pittsfield Conservation Commission State Senator Andrea Nuciforo State Rep Daniel E Bosley State Rep Christopher J Hodgkins State Rep Shaun P Kelly State Rep Peter J Larkin Housatonic River Initiative Jane W Gardner GE
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Andrew J Thomas Jr Esq GE Andrew T Silfer GE Ellen Ebert ChemRisk James R Bieke Shea amp Gardner James Nuss PE Blasland Bouck amp Lee Public Information Repositories - ECL I-R-IV(A)(1)
( with attachments)
ATTACHMENT A
PROPOSAL FOR ALTERNATIVE INPUT VALUES FOR THE HUMAN HEALTH RISK ASSESSMENT FOR THE HOUSATONIC RIVER
In accordance with the Agencies August 13 1997 comments on the Proposal for Human Health Risk Assessment for the Housatonic River General Electric Company (GE) proposes alternative input values for the following parameters (a) reference close (RfD) for reproductive and developmental effects of PCBs (b) enhanced soil ingestion rate for adult fanners and (c) dermal absorption factor for PCBs
Developmental RfD for PCBs
In Comment 10 of the final comments on the Proposal for Human Health Risk Assessment for the Housalonic River the Agencies stated that to evaluate developmental effects of PCBs GE should use the chronic RfD for Aroclor 1254 unless GE can provide a credible and relevant justification based on new data (not previously evaluated by EPA) for an alternative RfD for developmental effects Biased on new data that were not available at the time that EPA established its RfD for Aroclor 1254 CheniRisk has derived a RfD based on developmental efforts and GE proposes to use that value to evaluate such effects due to exposure of a pregnant female during the period of pregnancy
EPA published its current RfD for Aroclor 1254 (IRIS 1994) based on the dermal ocular and immunologic findings from a single study of rhesus monkeys reported by a number of researchers (Arnold et al 1993ab Tryphonas et al 1989 1991ab) In that study 16 adult female monkeys ingested gelatin capsules containing Aroclor 1254 at doses ranging from 0 to 80 ugkg-day for more than five years These monkeys achieved steady state after 25 months of exposure Preliminary results released by Arnold et al (1993ab) discussed the general health and clinical pathology evaluations of the adult monkeys that were conducted during the first 37 months of exposure Tryphonas et al (1989 1991ab) reported on the immunologic assessments of these monkeys after 23 and 55 months of exposure All of these evaluations were performed prior to the breeding phase of the study during which the monkeys were bred and the reproductive effects in the mothers and developmental effects in their offspring were evaluated Because the final results of the reproductive and developmental evaluations were not available at the time of the EPAs analysis these reproductive studies were not considered by the Agency in deriving its RfD for Aroclor 1254 (IRIS 1997)
Since the time that EPA established its RfD new data on the results of the breeding phase of the rhesus monkey study have become available Arnold et al (1995) completed their study of the reproductivedevelopmental impacts of PCBs on these monkeys and their offspring and published
ftigtLGEGEHOUSAT25laquoOU2RESPCOMMHEAlSSUEALTPAR2wplti CHEMRlSK - A DIVISION OF McLARENHART
their results in 1995 These data allow the derivation of an RfD that is specifically based on reproductive and developmental effects of Aroclor 1254 in rhesus monkeys
CheniRisk has developed such an RfD for use in the evaluation of subchronic exposures to a young woman during the nine months of her pregnancy in the relevant scenarios of the human health risk assessment for the Housatonic River Consistent with EPAs methodology in deriving RfDs from this group of studies several uncertainty factors have been applied to the lowest adverse effects level (LOAEL) of 0005 mgkg-day reported by Arnold et al (1995) to derive this RfD An uncertainty factor of 3 was used to account for interspecies extrapolation This uncertainly factor is appropriate due to the similarities in toxic responses and metabolism of PCBs by monkeys and humans and the general physiologic similarities between the species Another uncertainty factor of 3 was applied to account for the use of a LOAEL instead of a no adverse effect level (NOAEL) value This factor is appropriate because the effects observed in the young monkeys were not frank effects and are not necessarily adverse Finally an additional uncertainty factor of 10 was applied to account for interindividual variation or sensitivity within the population Application of the above safety factors results in a total uncertainty factor of 90 (3 x 3 x 10 == 90) which when applied to the LOAEL of 0005 mgkg-day results in a reproductivedeveloprnental RfD of 55 x 10s rngkg-day or 55 ngkgshyday
An additional uncertainty factor was not applied for translation from subchronic to chronic exposure duration because as DEP (1995) guidance recognizes exposure during nine months of pregnancy is a subchronic exposure scenario Moreover the actual overall exposure period for the adult female monkeys in the Arnold et al (1995) study (as in the prior studies from this group) was longer than one year and most of the adult monkeys had reached a steady stale body burden of PCBs before the studies of reproductive and developmental effects were initiated Hence the use of a subchronic exposure duration that is equivalent to the period of pregnancy (ie nine months) constitutes additional conservatism in the approach for assessing the developmental effects of PCBs
This subchronic RfD of 55 ngkg-day is a conservative estimate of the RfD in that it uses a safety factor of 10 to adjust for interindividual variation or sensitivity In fact because the RfD is based on effects in infant monkeys an already highly sensitive population a safety factor of 3 to account for interindividual variation among members of that sensitive subpopulation would be sufficient for developing an RfD In addition the study results appear to indicate that the infants may not have been more sensitive than the mothers as the changes observed in the infant monkeys were of similar or lesser severity than the maternal monkeys If a safety factor of 3 were used instead of the factor of 10 the result would be a total uncertainly factor of approximately 30 (3 x 3 x 3 == 27) resulting in a higher but still protective developmental RfD of 200 ngkg-day
Given the uncertainties associated with the derivation of an RfD for developmental effects GE has elected to take the more conservative approach and propose a subchronic developmental RfD of 55 x 10 mgkg-day for use in the Housatonic River risk assessment This value will be used to
PruLGDGEHOUSAT2593002RESKraquoMMHEAISSUEALTPAIU wpd - CHEMRlSK - A DIVISION OF McLARENHART
evaluate potential reproductive and developmental effects of PCBs in pregnant women and their offspring as a result of exposure during nine months of pregnancy in all scenarios for which this subchronic exposure scenario is proposed
Enhanced Soil Ingestion Rate for Adult Fanners
In Comment 56 of the final comments on the Proposal for Human Health Risk Assessment for the Housatonic River the Agencies stated that GE should use the DEP and EPA default enhanced soil ingestion rate of 480 nigday to evaluate potential soil ingestion exposures for the adult farmer unless it can provide a credible and relevant justification for an alternative rate
The current default enhanced ingestion rate of 480 mgday is an estimated rate of soil ingestion developed by Hawley (1985) based on his review of the soil ingestion literature available at that time While the estimates provided by Hawley have been used extensively to simulate high-end exposures via the soil ingestion pathway Hawleys estimates are not based on empirical data Rather Hawley derived his estimates based on assumptions about soildust levels on hands mouthing behavior and frequencies of indoor and outdoor activities According to the evaluation of soil ingestion studies conducted by EPA in preparing its August 1996 draft of the Exposure Factors Handbook Hawleys estimates must be considered conjectural due to the lack of supporting measurements
To derive his estimate of soil ingestion Hawley assumed that an adult while engaged in yard work or other physical activity would ingest the amount of soil that could coal the inside surface of the fingers and thumbs He estimated that soil could adhere to the skin at a rate of 35 mgcnr This estimated adherence factor was not measured rather it was based on the density of soil particles and Hawleys approximation of the depth of the layer of soil (50 pm) that might adhere to exposed skin on such an individual According to Sheppard (1995) Hawleys assumption of a 50 urn thick layer of soil on the arms and hands represents a very high and conspicuous soil load Sheppard reported that loads less than 1 mgcnr2 are more reasonable for making this calculation due to the fact that soil loads on the skin greater than 1 mgcm2 would be so noticeable that they would deter mouthing behavior until hands were washed or cleaned off
Since Hawleys approach was developed and Sheppard provided his evaluation of Hawleys approach new data on soil adherence have been published As reported by EPA (1996a) Kissel et al (1996) directly measured the soil loading on skin surfaces as a result of various occupational and recreational activities This study indicates that soil loadings vary with the type of activity and the body parts contacted As one would expect adherence appears to be greatest during outdoor activities such as farming and gardening and moire soildust tends to adhere to the hands and knees than to other areas of the body As measured by Kissel et al (1996) soil loadings for farmers hands range between 020 and 084 mgcm2 while adherence rates for other pants of their bodies are lower Values for other types of occupational exposures including irrigation workers and groundskeepers
ProuGEGEHOUSAT2mltX)2RESPCOMMlaquoEAISSUEALTPAR2wpd - CHEMRlSK - A DIVISION OF MCLARENHART
were measured to be less than 05 nigcnr In every case soil adherence during occupational exposures was measured to be considerably lower than Hawleys estimate of 35 mgcnr
In Dermal Exposure Assessment Principles and Applications (EPA 1992) 1EPA recommends a soil adherence range of 02 to 1 mgcm2 For typical exposure to outdoor soil DEP (1995) recommends a soil adherence value of 051 mgcnr2 All of these values are consistent with the adherence rates measured by Kissel et al (1996) suggesting that soil loadings greater than 10 mgcnr during outdoor activities such as fanning are not realistic
In addition it is unlikely that hand-to-mouth contact would occur at Hawleys estimated loading rate It is instead likely that individuals who have a soil loading of this magnitude would not pick up food or put their hands in their mouths before washing or wiping their hands to remove the excess soil
According to Sheppard (1995) it may be reasonable to assume that mouthing behavior could occur at a loading rate of 10 mgcnr As this loading rale is at the upper end of the range of soil loading rates supported by both EPA and DEP and is higher than the highest soil loading rates reported by Kissel et al for the hands of farmers or any other adult exposure this soil loading rate has been used in combination with Hawleys other assumptions to derive an enhanced soil ingestion rate for farmers
If one substitutes the value of 10 mgcm2 for Hawleys assumption of 35 mgcm2 and continues to use Hawleys other exposure assumptions the resulting enhanced outdoor soil ingestion rate is 137 nigday For the purposes of the Housatonic River risk assessment GE proposes to use this more empirically-based enhanced adult soil ingestion rate of 137 ingday for the adult fanner
Derma] Absorption Rate for PCBs
In Comment 62 of their final comments on the Proposal for Human Health Risk Assessment for the Housatonic River the Agencies stated that they disagree with the use of dermal ilbsorption values of 146 percent and 143 percent proposed by GE for soils and sediment respectively The Agencies reconinnended instead that GE use a dermal absorption factor of 14 percent unless GE provides a credible and relevant justification for an alternative dermal absorption factor GE believes that a dermal absorption factor of 14 percent is not justifiable for the Housatonic River risk assessment due to limitations of the study upon which it is based and site-specific factors that indicate that such an estimate likely overstates actual absorption of PCBs from soils and sediments at this site
The dermal absorption values originally proposed by GE for soils and sediment were calculated by ChemRisk based on data from Roy et al (1990) As discussed in detail in the EPAs (1992) Dermal Exposure Assessment Guidance Principles and Applications Roy et al (1990) studied percutaneous absorption of tetrachlorobiphenyl (TCB) through human skin (in vitro) TCB was applied to human skin for 96 hours at a concentration of 1000 rngkg in soil with a low (045
Prni_GEGEHOUSAT2SW 002RESPCOMMHEAISSlEALTPA]U wpd 4 CHEMRlSK bullbullA DIVISION OF IVICL AH ENHART
percent) organic carbon content Absorption through human skin was 736 percent after 96 hours of exposure but negligible after only eight hours of exposure Roy et al (1990) also studied absorption from soil by rat skin in vitro and in vivo Total in vitro absorption from high (1122 percent) organic carbon content soil over 96 hours was 964 percent while absorption from low organic carbon soil in vitro in rats was 3195 percent over 96 hours For low organic carbon soil the absorption for the rat in vivo was 497 percent absorption after 96 hours
In its analysis EPA (1992) adjusted the Roy et al data to derive estimates of in vivo absorption of TCB in humans based on 24-hour exposure This was accomplished by adjusting the data to reflect differences between in vitro and in vivo tests rat and human skin and organic carbon content of the soil The adjusted percent TCB absorbed from soil was estimated to range from 063 percent for soil with high organic carbon content to 21 percent for soil with low organic carbon content Considering the uncertainty in these estimates EPA (1992) recommended a range of 06 percent to 6 percent for the percent of TCB dermally absorbed from the soil Moreover by comparing the Roy et al (1990) data to in vivo data from other bioavailability studies using other PCBs EPA (1992) concluded that the uptake of TCB was similar to that of other PCBs and that the range of 06 percent to 6 percent absorption for TCB is generally appropriate for PCBs
As these data indicate the dermal absorption of PCBs in soil is highly dependent on the organic carbon content of the soil GE proposed to account for this dependency by extrapolating from the Roy et al data to the relatively high site-specific organic carbon content of soils and sediments at the site DEP (1993) had previously agreed that it was appropriate to derive dermal absorption factors based on site-specific organic carbon content data as long as the organic carbon values used were based on reliable dala Because there are substantial data on the organic carbon contents of site soils and sediments GE proposed to use site-specific dermal absorption factors based on extrapolations of the Roy et al (1990) findings
In Comment 62 the Agencies stated that they no longer support the site-specific dermal absorption values previously derived by GE due to the findings of a study by Wester et al (1993) which indicated that dermal absorption of PCBs may be higher than that estimated by EPA using the Roy et al (1990) data The Wester et al (1993) study was designed to measure the extent to which Aroclors 1242 and 1254 would partition out of soil and be absorbed through the skin Wester et al (1993) added radio-labeled Aroclor 1242 and Aroclor 1234 to soil containing 26 percent sand 26 percent clay 48 percent silt and 09 percent organic carbon content Soils were mixed by hand to final concentrations of 44 mgkg Aroclor 1242 and 23 mgkg Aroclor 1254 These soils were then applied to the clipped abdominal skin of adult female rhesus monkeys for a period of 24 hours in a manner that would prevent the animals from licking or scratching at the skirt and would prevent exfoliated skin from contaminating urine or feces The skin site was covered with a non-occlusive cover that permitted air and moisture to move freely to and from the skin but retained the soil at the application site Urine and feces were collected during the exposure period After 24 hours skin
Proi_GEGEHOVSArumW2MSPCOMMVHEAISSUEALTPARiwpltl bull CHEMRlSK - A DIVISION OF MCLARENHART
was washed and urine and feces were periodically measured and analyzed for PCBs for 34 days following exposure
Percutaneous absorption was determined by urinary and fecal excretion following topical and intravenous administration Based on their measured recoveries combined with excretion efficiency data previously measured at their laboratory Wester et al (1993) concluded that the percutaneous absorptions of Aroclor 1242 and Aroclor 1254 from soil were 138 plusmn 27 percent and 141 + 10 percent of dose respectively Recovery of PCBs from skin was 83 percent for Aroclor 1242 and 72 percent for Aroclor 1254 most of the recovered dose was in the residual soil indicating that the PCBs had remained bound to soil during that 24-hour period rather than adsorbing to skin
While the Wester et al (1993) study was a well-conducted study that used appropriate experimental methodology there are several aspects of the study that limit its usefulness as a basis for developing dermal absorption factors for this site-specific risk assessment First Wester et al (1993) evaluated soils that had an organic carbon content of 09 percent and they did not test for variations in dermal absorption from soils with higher organic carbon contents This organic carbon content is very low and is not consistent with the levels of organic carbon content found in soils and sediments of the Housatonic River and its floodplain (ranging from 01 - 26 percent with arithmetic means of 50 and 53 percent for soils and sediments respectively) It is likely based on the clear trends shown in the Roy et al (1990) data that if higher levels of organic carbon had been tested by Wester et al (1993) the result would have been lower levels of percutaneous absorption
Second Wester et al (1993) applied soil to the animals skin at a rate of 40 ing soilcm2 skin (resulting in PCB concentrations on the skin of 175 ug PCBcm for Aroclor 1242 and 091 pg PCBcm2 for Aroclor 1254) This application rate is substantially greater than the adherence rates measured by Kissel et al (1996) or considered appropriate by DEP or EPA This higher rate of application may have increased the absorption of PCBs through the skin
Third the study used freshly spiked commercial PCB mixtures As discussed by EPA (1996b) in its reassessment of the carcinogenic potential of environmental PCB mixtures the composition of PCB mixtures changes over time through differential partitioning and chemical transformation of the component congeners For example congeners of lower chlorine content tend to be more volatile and also more soluble in water with rates of vaporization and relative water solubilities varying over several orders of magnitude between congeners These processes of volatilization and dissolution would appear to reduce the relative dermal absorption of a weathered PCB mixture compared to that of a freshly spiked sample In addition a weathered PCB mixture should form a tighter affinity to an environmental soil matrix over time further reducing its availability to become dermally absorbed
Finally Guy and Hadgraft (1987) reported that the permeability of skin in various parts of the body may be highly variable They reported that studies of hydrocortisone malathion and parathion have
ProjJ3DGEHOUSATU5laquoU02RESKOMMHEAISSUEALTPARlwpd - CHEMRlSK - A DIVISION OF McLARENHART
indicated that absorption across leg and forearm skin is similar but that the skin of the trunk is 25 times more permeable than the skin of the forearm or leg If this is also the case for PCBs it may be reasonable to conclude that absorption through the abdominal skin of the Wester at al (1993) monkeys may overestimate absorption through the skin of the arms or legs by as much as a factor of 25 If this were shown to be the case the result would be a dermal absorption of approximately 6 percent similar to the absorption factor recommended by EPA (1992) based on the Roy et al (1990) study for low carbon content soils over 24 hours of exposure
While the Wester et al (1993) study was a well conducted study the above-outlined limitations and uncertainties undermine its usefulness for this site-specific risk assessment In addition EPA has convened a dermal workgroup to evaluate the dermal absorption of PCBs and make recommendations for a revised absorption factor if appropriate This work group has not yet made a final recommendation When the work group has finished its analysis and EPA makes a recommendation on this issue GE will review that recommendation and all available data on dermal absorption of PCBs If however such a recommendation has not been made by the time that the risk assessment is conducted GE proposes to use the upper bound of current Agency guidance 6 percent for the evaluation of dermal absorption of PCBs from soil and sediment
References
Arnold DL F Bryce R Stapley PP McGuire D Burns JR Tanner and K Karpinski 1993a lexicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part 1A Prebreeding phase - clinical health findings Fd Chem Toxicol 31799-810
Arnold DL F Bryce K Karpinski J Mes S Fernie H Tryphonas J Truelove PP McGuire D Burns JR Tanner R Stapley ZZ Zawidzka and D Basford 1993b Toxicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part IB Prebreeding phase - clinical and analytical laboratory findings Fd Chem Toxicol 31811-824
Arnold D L F Bryce PP McGuire R Stapley JR Tanner E Wrenshall J Mes S Fernie H Tryphonas S Hayward and S Malcolm 1995 Toxicological consequences of Aroclor 1254 ingestion by female rhesus (Macaco mulatto) monkeys Part 2 Reproduction and infant findings Fd Chem Toxicol 33(6)457-474
DEP 1995 Guidance for Disposal Site Risk Characterization - In Support of the Massachusetts Contingency Plan - Interim Final Policy Massachusetts Department of Environmental Protection Bureau of Waste Site Cleanup and Office of Research and Standards Boston MA WSCORS-95shy141 July
DEP 1993 Memorandum to Catherine Wanat Project Manager WEROfrom Meg Harvey ORS Re Review of Revised Risk Assessment to Evaluate Need for Short-Term Measures in the 10-Year
ProjJDEGEHOliSATU5raquo3002RESrcOMMHEAISSUEALTPAIUwpltl CHEMRlSK - A DIVISION OF McLARENHART
Floodplain of the Housatonic River Massachusetts Department of Environmental Protection Office of Research and Standards Boston MA August 5
EFA 1996a Exposure Factors Handbook Volume I of III General Factors - Review Draft US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-95002Ba August
EPA 1996b Proposed Guidelines for Carcinogen Risk Assessment US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-92003C April
EPA 1992Dermal Exposure Assessment Principles and Applications US Environmental Protection Agency Office of Research and Development Washington DC EPA6008-9101 IB January
Guy RH and J Hadgraft 1987 Principles of skin permeability relevant to chemical exposure PB89-130009 NIOSH Grant K01-OH-00017 National Technical Information Service US Department of Commerce Springfield VA
Hawley JK 1985 Assessment of health risk from exposure to contaminated soil Risk Analysis 5289-302
IRIS 1997 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
IRIS 1994 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
Kissel JC KY Richter and RA Fenske 1996 Field measurement of dermal soil loading attributable to various activities Implications for exposure assessment Risk Anal 16 (1) 115-125
Roy TA JJ Yang AI Krueger and CR Mackerer 1990 Percutaneous absorption of neat 2378-tetrachlorodibenzo-p-dioxin (TCDD) and TCDD sorbed on soils Toxicology 10( I )308
Sheppard SC 1995 Parameter values to model the soil ingestion pathway Environmental Monitoring and Assessment 3427-44
Tryphonas H S Hayward L OGrady JCK Loo DL Arnold F Bryce and ZZ Zawidzka 1989 Immunotoxicity studies of PCB (Aroclor 1254) in the adult rhesus (Macaco mulatto) monkey - Preliminary report Int J Immunoph 11 (2) 199-206
PrOLGEGEHOllSAT2m002VRESPCOMMHEAlSSllEALTPAR2wpltj laquo CHEMRlSK bullbull A DIVISION OF McLARENHART
Tiyphonas H MI Luster G Schiffinan LL Dawson M Hodgen D Germolec S Hayward F Bryce JCK Loo F Mandy and DL Arnold 199 la Effect ofchronic exposure of PCB (Aroclor 1254) on specific and nonspecific immune parameters in the rhesus (Macaca mulatto) monkey FundAppl Toxicol 16773-786
Tiyphonas H MI Luster KL White PH Naylor MR EKlos GR Burleson D Germolec M Hodgen S Hayward and DL Arnold 1991b Effects of PCB (Aroclorreg 1254) on non-specific immune parameters in rhesus (Macaca mulatto) monkeys Int Immunoph 13(6)639-648
Wester RC HI Maibach L Sedik and J Melendres 1993 Percutaneous absorption of PCBs from soil In vivo rhesus monkey in vitro human skin and biding to powdered human stratum corneum Journal of Toxicology and Environmental Health 39375-282
Piuj_GEGEHOLPSATU5raquo3 (raquo2RESPCOMMHEAJSSUEAJ_TPAR2 wpd CHEMRjISK1 bullbull A DIVISION OF MCLARENHART
ATTACHMENT B
SCHEDULE - HUMAN HEALTH FOR HOUSATONIC
Deliverable (vith explanatory notes) Due Date
1 Baekcalculated Risk-Based Concentrations (RBCs) for PCBs for Residential Scenario 30 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in soil for the residential scenario taking into account Attachment A ambient air and indoor dust exposures and the potential presence of a garden It will also present all exposure and toxicity parameter values used in deriving those RBCs In addition it will include an evaluation of exposures to PCBs from lawn mowing and a description of the methodology used in that evaluation
Backcaiculated RBCs for PCBs for Other Scenarios 60 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in the pertinent media for the scenarios described Attachment A beiow together with all exposure and toxicity parameter values used in deriving those RBCs
o General recreational o Canoeing Q Swimming o Dirt hiking o Current commercial use o Current agricultural use o Utility worker o Construction worker o Fish consumption (from recreational fishing)
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Deliverable (with explanatory notes) Lme uate
3 Proposal Addendum Regarding Useable Data Other COPCs and Other Biota January 30 1998
This subrnittal will present the results of andor proposals for several tasks in the risk assessment process
a Data evaluation This subrnittal will present the results of the data evaluation as described in Section 3 of the Risk Assessment Proposal and will include a summarization of useable data This evaluation will necessarily be based on available data and thus will not be able to take account of the results of any additional Phase IIRFI investigations that may be required by the Agencies The data evaluation is estimated to take approximately 2-3 months and must be completed before the selection of other (non-PCB) Chemicals of Potential Concern (COPCs) car- be conducted
b Proposal on other COPCs This subrnittal will also present a proposal regarding other (non-PCB) COPCs It will include
o Identification of other COPCs based on the data evaluation results and the selection criteria described in the Proposal (including comparison to upstream levels)
o Dose-response assessment and proposal of toxicity values for these COPCs o Proposal of RAFs and other chemical-specific exposure parameters for these COPCs o Identification of areas where these COPCs have been detected in concentrations exceeding
upstream levels and o Identification of pertinent exposure scenarios for those areas
These tasks will take approximately 2 months after completion of the data evaluation
c Proposal regarding consumption of other biota This submittal will further include a proposal for the evaluation of consumption of biota other than fish It will include a proposal as to the specific species to be evaluated the method of evaluation (quantitative or qualitative) and the parameter values to be used in the quantitative evaluations (Note This item may have to be postponed to a later date if GE has not received from the Agencies the results of the Univ of Mass fiddlehead fern study in the time for consideration prior to the due date for this subrnittal)
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Deliverable (with explanatory notes)
4 Backcalculated RBCs for Other COPCs for Relevant Scenarios
This subrnittal will present the backcalculated RBCs for the other identified COPCs in the pertinent media for the exposure scenarios identified as relevant to the areas where such COPCs have been detected It will also present all exposure and toxieity parameter values used in deriving those COPCs
Backcaiculated RBCs for Consumption of Other Biota
This subrnitta will present the backcalculated RBCs for the consumption of biota other than fish These RBCs win be presented for those species for which quantitative evaluation was conducted (The qualitative evaluation of other species will be included in the final risk assessment report)
6 Interim Risk Assessment Report - Application of RBCs Based on Current Use
This subrnkta will provide an Interim report on the risk assessment It will include a brief summary of the approach used and the prior submittals including the exposure scenarios and RBCs for each scenario It will also present sample forward risk calculations for each scenario using a dummy Exposure Point Concentration (EPC) It will further present the results of the application of the RBCs for PCBs (and other COPCs where applicable) to the relevant exposure points under current use assumptions This will include
o Identification of current uses of the site (by area) and the applicable exposure scenario based on such use o Identification of exposure points for each scenario based on current use o Calculation of EPCs for each exposure point (for PCBs and other COPCs where measured)
including a justification for the method of calculating them o Comparison of EPCs to applicable RBCs for each exposure point o Conclusion for each exposure point regarding presence of significant risk for applicable scenario and o Brief discussion of uncertainties and risk perspective
30 days from Agencies approval of proposal or- other COPCs (hern 3b)
30 days from Agencies approval of proposal for evaluation of consumption of other biota (Item 3c)
75 days from Agencies approval of Item 1 2 4 or 5 whichever is latest
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
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Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
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concentrations for other exposure scenarios It also indicated that GE could propose to complete the risk-based concentrations and apply them to the site based on current uses prior to conducting the mapping exercise to identify foreseeable future uses and applying the risk-based concentrations to the site based on such future uses Considering that advice as well as the steps outlined in GEs February 1996 Proposal as modified by the Agencies comments of August 13 1997 GE has developed a proposed schedule for submission of the necessary risk assessment deliverable) That proposed schedule along with explanatory notes is set forth in Attachment B
This schedule of activities would begin upon receipt of the Agencies response to the proposal in Attachment A as well as approval of the proposed schedule in Attachment B In the meantime however we would like to discuss these proposals with you Please call me to schedule a time for such a discussion or if you have any questions about this matter
Very truly yours
Jane Magee Manager PittsfieldHousatonic
Remediation Programs
Attachments
cc Mary Holland DEP Alan Weinberg DEP Robert Bell Esq DEP Ralph Child Esq DEP Margaret Harvey DEP Matthew Hoagland EPA Douglas J Luckerman Esq EPA Charles Fredette Conn DEP Mayor Edward Reilly City of Pittsfield Pittsfield Commissioner of Health Pittsfield Conservation Commission State Senator Andrea Nuciforo State Rep Daniel E Bosley State Rep Christopher J Hodgkins State Rep Shaun P Kelly State Rep Peter J Larkin Housatonic River Initiative Jane W Gardner GE
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Andrew J Thomas Jr Esq GE Andrew T Silfer GE Ellen Ebert ChemRisk James R Bieke Shea amp Gardner James Nuss PE Blasland Bouck amp Lee Public Information Repositories - ECL I-R-IV(A)(1)
( with attachments)
ATTACHMENT A
PROPOSAL FOR ALTERNATIVE INPUT VALUES FOR THE HUMAN HEALTH RISK ASSESSMENT FOR THE HOUSATONIC RIVER
In accordance with the Agencies August 13 1997 comments on the Proposal for Human Health Risk Assessment for the Housatonic River General Electric Company (GE) proposes alternative input values for the following parameters (a) reference close (RfD) for reproductive and developmental effects of PCBs (b) enhanced soil ingestion rate for adult fanners and (c) dermal absorption factor for PCBs
Developmental RfD for PCBs
In Comment 10 of the final comments on the Proposal for Human Health Risk Assessment for the Housalonic River the Agencies stated that to evaluate developmental effects of PCBs GE should use the chronic RfD for Aroclor 1254 unless GE can provide a credible and relevant justification based on new data (not previously evaluated by EPA) for an alternative RfD for developmental effects Biased on new data that were not available at the time that EPA established its RfD for Aroclor 1254 CheniRisk has derived a RfD based on developmental efforts and GE proposes to use that value to evaluate such effects due to exposure of a pregnant female during the period of pregnancy
EPA published its current RfD for Aroclor 1254 (IRIS 1994) based on the dermal ocular and immunologic findings from a single study of rhesus monkeys reported by a number of researchers (Arnold et al 1993ab Tryphonas et al 1989 1991ab) In that study 16 adult female monkeys ingested gelatin capsules containing Aroclor 1254 at doses ranging from 0 to 80 ugkg-day for more than five years These monkeys achieved steady state after 25 months of exposure Preliminary results released by Arnold et al (1993ab) discussed the general health and clinical pathology evaluations of the adult monkeys that were conducted during the first 37 months of exposure Tryphonas et al (1989 1991ab) reported on the immunologic assessments of these monkeys after 23 and 55 months of exposure All of these evaluations were performed prior to the breeding phase of the study during which the monkeys were bred and the reproductive effects in the mothers and developmental effects in their offspring were evaluated Because the final results of the reproductive and developmental evaluations were not available at the time of the EPAs analysis these reproductive studies were not considered by the Agency in deriving its RfD for Aroclor 1254 (IRIS 1997)
Since the time that EPA established its RfD new data on the results of the breeding phase of the rhesus monkey study have become available Arnold et al (1995) completed their study of the reproductivedevelopmental impacts of PCBs on these monkeys and their offspring and published
ftigtLGEGEHOUSAT25laquoOU2RESPCOMMHEAlSSUEALTPAR2wplti CHEMRlSK - A DIVISION OF McLARENHART
their results in 1995 These data allow the derivation of an RfD that is specifically based on reproductive and developmental effects of Aroclor 1254 in rhesus monkeys
CheniRisk has developed such an RfD for use in the evaluation of subchronic exposures to a young woman during the nine months of her pregnancy in the relevant scenarios of the human health risk assessment for the Housatonic River Consistent with EPAs methodology in deriving RfDs from this group of studies several uncertainty factors have been applied to the lowest adverse effects level (LOAEL) of 0005 mgkg-day reported by Arnold et al (1995) to derive this RfD An uncertainty factor of 3 was used to account for interspecies extrapolation This uncertainly factor is appropriate due to the similarities in toxic responses and metabolism of PCBs by monkeys and humans and the general physiologic similarities between the species Another uncertainty factor of 3 was applied to account for the use of a LOAEL instead of a no adverse effect level (NOAEL) value This factor is appropriate because the effects observed in the young monkeys were not frank effects and are not necessarily adverse Finally an additional uncertainty factor of 10 was applied to account for interindividual variation or sensitivity within the population Application of the above safety factors results in a total uncertainty factor of 90 (3 x 3 x 10 == 90) which when applied to the LOAEL of 0005 mgkg-day results in a reproductivedeveloprnental RfD of 55 x 10s rngkg-day or 55 ngkgshyday
An additional uncertainty factor was not applied for translation from subchronic to chronic exposure duration because as DEP (1995) guidance recognizes exposure during nine months of pregnancy is a subchronic exposure scenario Moreover the actual overall exposure period for the adult female monkeys in the Arnold et al (1995) study (as in the prior studies from this group) was longer than one year and most of the adult monkeys had reached a steady stale body burden of PCBs before the studies of reproductive and developmental effects were initiated Hence the use of a subchronic exposure duration that is equivalent to the period of pregnancy (ie nine months) constitutes additional conservatism in the approach for assessing the developmental effects of PCBs
This subchronic RfD of 55 ngkg-day is a conservative estimate of the RfD in that it uses a safety factor of 10 to adjust for interindividual variation or sensitivity In fact because the RfD is based on effects in infant monkeys an already highly sensitive population a safety factor of 3 to account for interindividual variation among members of that sensitive subpopulation would be sufficient for developing an RfD In addition the study results appear to indicate that the infants may not have been more sensitive than the mothers as the changes observed in the infant monkeys were of similar or lesser severity than the maternal monkeys If a safety factor of 3 were used instead of the factor of 10 the result would be a total uncertainly factor of approximately 30 (3 x 3 x 3 == 27) resulting in a higher but still protective developmental RfD of 200 ngkg-day
Given the uncertainties associated with the derivation of an RfD for developmental effects GE has elected to take the more conservative approach and propose a subchronic developmental RfD of 55 x 10 mgkg-day for use in the Housatonic River risk assessment This value will be used to
PruLGDGEHOUSAT2593002RESKraquoMMHEAISSUEALTPAIU wpd - CHEMRlSK - A DIVISION OF McLARENHART
evaluate potential reproductive and developmental effects of PCBs in pregnant women and their offspring as a result of exposure during nine months of pregnancy in all scenarios for which this subchronic exposure scenario is proposed
Enhanced Soil Ingestion Rate for Adult Fanners
In Comment 56 of the final comments on the Proposal for Human Health Risk Assessment for the Housatonic River the Agencies stated that GE should use the DEP and EPA default enhanced soil ingestion rate of 480 nigday to evaluate potential soil ingestion exposures for the adult farmer unless it can provide a credible and relevant justification for an alternative rate
The current default enhanced ingestion rate of 480 mgday is an estimated rate of soil ingestion developed by Hawley (1985) based on his review of the soil ingestion literature available at that time While the estimates provided by Hawley have been used extensively to simulate high-end exposures via the soil ingestion pathway Hawleys estimates are not based on empirical data Rather Hawley derived his estimates based on assumptions about soildust levels on hands mouthing behavior and frequencies of indoor and outdoor activities According to the evaluation of soil ingestion studies conducted by EPA in preparing its August 1996 draft of the Exposure Factors Handbook Hawleys estimates must be considered conjectural due to the lack of supporting measurements
To derive his estimate of soil ingestion Hawley assumed that an adult while engaged in yard work or other physical activity would ingest the amount of soil that could coal the inside surface of the fingers and thumbs He estimated that soil could adhere to the skin at a rate of 35 mgcnr This estimated adherence factor was not measured rather it was based on the density of soil particles and Hawleys approximation of the depth of the layer of soil (50 pm) that might adhere to exposed skin on such an individual According to Sheppard (1995) Hawleys assumption of a 50 urn thick layer of soil on the arms and hands represents a very high and conspicuous soil load Sheppard reported that loads less than 1 mgcnr2 are more reasonable for making this calculation due to the fact that soil loads on the skin greater than 1 mgcm2 would be so noticeable that they would deter mouthing behavior until hands were washed or cleaned off
Since Hawleys approach was developed and Sheppard provided his evaluation of Hawleys approach new data on soil adherence have been published As reported by EPA (1996a) Kissel et al (1996) directly measured the soil loading on skin surfaces as a result of various occupational and recreational activities This study indicates that soil loadings vary with the type of activity and the body parts contacted As one would expect adherence appears to be greatest during outdoor activities such as farming and gardening and moire soildust tends to adhere to the hands and knees than to other areas of the body As measured by Kissel et al (1996) soil loadings for farmers hands range between 020 and 084 mgcm2 while adherence rates for other pants of their bodies are lower Values for other types of occupational exposures including irrigation workers and groundskeepers
ProuGEGEHOUSAT2mltX)2RESPCOMMlaquoEAISSUEALTPAR2wpd - CHEMRlSK - A DIVISION OF MCLARENHART
were measured to be less than 05 nigcnr In every case soil adherence during occupational exposures was measured to be considerably lower than Hawleys estimate of 35 mgcnr
In Dermal Exposure Assessment Principles and Applications (EPA 1992) 1EPA recommends a soil adherence range of 02 to 1 mgcm2 For typical exposure to outdoor soil DEP (1995) recommends a soil adherence value of 051 mgcnr2 All of these values are consistent with the adherence rates measured by Kissel et al (1996) suggesting that soil loadings greater than 10 mgcnr during outdoor activities such as fanning are not realistic
In addition it is unlikely that hand-to-mouth contact would occur at Hawleys estimated loading rate It is instead likely that individuals who have a soil loading of this magnitude would not pick up food or put their hands in their mouths before washing or wiping their hands to remove the excess soil
According to Sheppard (1995) it may be reasonable to assume that mouthing behavior could occur at a loading rate of 10 mgcnr As this loading rale is at the upper end of the range of soil loading rates supported by both EPA and DEP and is higher than the highest soil loading rates reported by Kissel et al for the hands of farmers or any other adult exposure this soil loading rate has been used in combination with Hawleys other assumptions to derive an enhanced soil ingestion rate for farmers
If one substitutes the value of 10 mgcm2 for Hawleys assumption of 35 mgcm2 and continues to use Hawleys other exposure assumptions the resulting enhanced outdoor soil ingestion rate is 137 nigday For the purposes of the Housatonic River risk assessment GE proposes to use this more empirically-based enhanced adult soil ingestion rate of 137 ingday for the adult fanner
Derma] Absorption Rate for PCBs
In Comment 62 of their final comments on the Proposal for Human Health Risk Assessment for the Housatonic River the Agencies stated that they disagree with the use of dermal ilbsorption values of 146 percent and 143 percent proposed by GE for soils and sediment respectively The Agencies reconinnended instead that GE use a dermal absorption factor of 14 percent unless GE provides a credible and relevant justification for an alternative dermal absorption factor GE believes that a dermal absorption factor of 14 percent is not justifiable for the Housatonic River risk assessment due to limitations of the study upon which it is based and site-specific factors that indicate that such an estimate likely overstates actual absorption of PCBs from soils and sediments at this site
The dermal absorption values originally proposed by GE for soils and sediment were calculated by ChemRisk based on data from Roy et al (1990) As discussed in detail in the EPAs (1992) Dermal Exposure Assessment Guidance Principles and Applications Roy et al (1990) studied percutaneous absorption of tetrachlorobiphenyl (TCB) through human skin (in vitro) TCB was applied to human skin for 96 hours at a concentration of 1000 rngkg in soil with a low (045
Prni_GEGEHOUSAT2SW 002RESPCOMMHEAISSlEALTPA]U wpd 4 CHEMRlSK bullbullA DIVISION OF IVICL AH ENHART
percent) organic carbon content Absorption through human skin was 736 percent after 96 hours of exposure but negligible after only eight hours of exposure Roy et al (1990) also studied absorption from soil by rat skin in vitro and in vivo Total in vitro absorption from high (1122 percent) organic carbon content soil over 96 hours was 964 percent while absorption from low organic carbon soil in vitro in rats was 3195 percent over 96 hours For low organic carbon soil the absorption for the rat in vivo was 497 percent absorption after 96 hours
In its analysis EPA (1992) adjusted the Roy et al data to derive estimates of in vivo absorption of TCB in humans based on 24-hour exposure This was accomplished by adjusting the data to reflect differences between in vitro and in vivo tests rat and human skin and organic carbon content of the soil The adjusted percent TCB absorbed from soil was estimated to range from 063 percent for soil with high organic carbon content to 21 percent for soil with low organic carbon content Considering the uncertainty in these estimates EPA (1992) recommended a range of 06 percent to 6 percent for the percent of TCB dermally absorbed from the soil Moreover by comparing the Roy et al (1990) data to in vivo data from other bioavailability studies using other PCBs EPA (1992) concluded that the uptake of TCB was similar to that of other PCBs and that the range of 06 percent to 6 percent absorption for TCB is generally appropriate for PCBs
As these data indicate the dermal absorption of PCBs in soil is highly dependent on the organic carbon content of the soil GE proposed to account for this dependency by extrapolating from the Roy et al data to the relatively high site-specific organic carbon content of soils and sediments at the site DEP (1993) had previously agreed that it was appropriate to derive dermal absorption factors based on site-specific organic carbon content data as long as the organic carbon values used were based on reliable dala Because there are substantial data on the organic carbon contents of site soils and sediments GE proposed to use site-specific dermal absorption factors based on extrapolations of the Roy et al (1990) findings
In Comment 62 the Agencies stated that they no longer support the site-specific dermal absorption values previously derived by GE due to the findings of a study by Wester et al (1993) which indicated that dermal absorption of PCBs may be higher than that estimated by EPA using the Roy et al (1990) data The Wester et al (1993) study was designed to measure the extent to which Aroclors 1242 and 1254 would partition out of soil and be absorbed through the skin Wester et al (1993) added radio-labeled Aroclor 1242 and Aroclor 1234 to soil containing 26 percent sand 26 percent clay 48 percent silt and 09 percent organic carbon content Soils were mixed by hand to final concentrations of 44 mgkg Aroclor 1242 and 23 mgkg Aroclor 1254 These soils were then applied to the clipped abdominal skin of adult female rhesus monkeys for a period of 24 hours in a manner that would prevent the animals from licking or scratching at the skirt and would prevent exfoliated skin from contaminating urine or feces The skin site was covered with a non-occlusive cover that permitted air and moisture to move freely to and from the skin but retained the soil at the application site Urine and feces were collected during the exposure period After 24 hours skin
Proi_GEGEHOVSArumW2MSPCOMMVHEAISSUEALTPARiwpltl bull CHEMRlSK - A DIVISION OF MCLARENHART
was washed and urine and feces were periodically measured and analyzed for PCBs for 34 days following exposure
Percutaneous absorption was determined by urinary and fecal excretion following topical and intravenous administration Based on their measured recoveries combined with excretion efficiency data previously measured at their laboratory Wester et al (1993) concluded that the percutaneous absorptions of Aroclor 1242 and Aroclor 1254 from soil were 138 plusmn 27 percent and 141 + 10 percent of dose respectively Recovery of PCBs from skin was 83 percent for Aroclor 1242 and 72 percent for Aroclor 1254 most of the recovered dose was in the residual soil indicating that the PCBs had remained bound to soil during that 24-hour period rather than adsorbing to skin
While the Wester et al (1993) study was a well-conducted study that used appropriate experimental methodology there are several aspects of the study that limit its usefulness as a basis for developing dermal absorption factors for this site-specific risk assessment First Wester et al (1993) evaluated soils that had an organic carbon content of 09 percent and they did not test for variations in dermal absorption from soils with higher organic carbon contents This organic carbon content is very low and is not consistent with the levels of organic carbon content found in soils and sediments of the Housatonic River and its floodplain (ranging from 01 - 26 percent with arithmetic means of 50 and 53 percent for soils and sediments respectively) It is likely based on the clear trends shown in the Roy et al (1990) data that if higher levels of organic carbon had been tested by Wester et al (1993) the result would have been lower levels of percutaneous absorption
Second Wester et al (1993) applied soil to the animals skin at a rate of 40 ing soilcm2 skin (resulting in PCB concentrations on the skin of 175 ug PCBcm for Aroclor 1242 and 091 pg PCBcm2 for Aroclor 1254) This application rate is substantially greater than the adherence rates measured by Kissel et al (1996) or considered appropriate by DEP or EPA This higher rate of application may have increased the absorption of PCBs through the skin
Third the study used freshly spiked commercial PCB mixtures As discussed by EPA (1996b) in its reassessment of the carcinogenic potential of environmental PCB mixtures the composition of PCB mixtures changes over time through differential partitioning and chemical transformation of the component congeners For example congeners of lower chlorine content tend to be more volatile and also more soluble in water with rates of vaporization and relative water solubilities varying over several orders of magnitude between congeners These processes of volatilization and dissolution would appear to reduce the relative dermal absorption of a weathered PCB mixture compared to that of a freshly spiked sample In addition a weathered PCB mixture should form a tighter affinity to an environmental soil matrix over time further reducing its availability to become dermally absorbed
Finally Guy and Hadgraft (1987) reported that the permeability of skin in various parts of the body may be highly variable They reported that studies of hydrocortisone malathion and parathion have
ProjJ3DGEHOUSATU5laquoU02RESKOMMHEAISSUEALTPARlwpd - CHEMRlSK - A DIVISION OF McLARENHART
indicated that absorption across leg and forearm skin is similar but that the skin of the trunk is 25 times more permeable than the skin of the forearm or leg If this is also the case for PCBs it may be reasonable to conclude that absorption through the abdominal skin of the Wester at al (1993) monkeys may overestimate absorption through the skin of the arms or legs by as much as a factor of 25 If this were shown to be the case the result would be a dermal absorption of approximately 6 percent similar to the absorption factor recommended by EPA (1992) based on the Roy et al (1990) study for low carbon content soils over 24 hours of exposure
While the Wester et al (1993) study was a well conducted study the above-outlined limitations and uncertainties undermine its usefulness for this site-specific risk assessment In addition EPA has convened a dermal workgroup to evaluate the dermal absorption of PCBs and make recommendations for a revised absorption factor if appropriate This work group has not yet made a final recommendation When the work group has finished its analysis and EPA makes a recommendation on this issue GE will review that recommendation and all available data on dermal absorption of PCBs If however such a recommendation has not been made by the time that the risk assessment is conducted GE proposes to use the upper bound of current Agency guidance 6 percent for the evaluation of dermal absorption of PCBs from soil and sediment
References
Arnold DL F Bryce R Stapley PP McGuire D Burns JR Tanner and K Karpinski 1993a lexicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part 1A Prebreeding phase - clinical health findings Fd Chem Toxicol 31799-810
Arnold DL F Bryce K Karpinski J Mes S Fernie H Tryphonas J Truelove PP McGuire D Burns JR Tanner R Stapley ZZ Zawidzka and D Basford 1993b Toxicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part IB Prebreeding phase - clinical and analytical laboratory findings Fd Chem Toxicol 31811-824
Arnold D L F Bryce PP McGuire R Stapley JR Tanner E Wrenshall J Mes S Fernie H Tryphonas S Hayward and S Malcolm 1995 Toxicological consequences of Aroclor 1254 ingestion by female rhesus (Macaco mulatto) monkeys Part 2 Reproduction and infant findings Fd Chem Toxicol 33(6)457-474
DEP 1995 Guidance for Disposal Site Risk Characterization - In Support of the Massachusetts Contingency Plan - Interim Final Policy Massachusetts Department of Environmental Protection Bureau of Waste Site Cleanup and Office of Research and Standards Boston MA WSCORS-95shy141 July
DEP 1993 Memorandum to Catherine Wanat Project Manager WEROfrom Meg Harvey ORS Re Review of Revised Risk Assessment to Evaluate Need for Short-Term Measures in the 10-Year
ProjJDEGEHOliSATU5raquo3002RESrcOMMHEAISSUEALTPAIUwpltl CHEMRlSK - A DIVISION OF McLARENHART
Floodplain of the Housatonic River Massachusetts Department of Environmental Protection Office of Research and Standards Boston MA August 5
EFA 1996a Exposure Factors Handbook Volume I of III General Factors - Review Draft US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-95002Ba August
EPA 1996b Proposed Guidelines for Carcinogen Risk Assessment US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-92003C April
EPA 1992Dermal Exposure Assessment Principles and Applications US Environmental Protection Agency Office of Research and Development Washington DC EPA6008-9101 IB January
Guy RH and J Hadgraft 1987 Principles of skin permeability relevant to chemical exposure PB89-130009 NIOSH Grant K01-OH-00017 National Technical Information Service US Department of Commerce Springfield VA
Hawley JK 1985 Assessment of health risk from exposure to contaminated soil Risk Analysis 5289-302
IRIS 1997 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
IRIS 1994 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
Kissel JC KY Richter and RA Fenske 1996 Field measurement of dermal soil loading attributable to various activities Implications for exposure assessment Risk Anal 16 (1) 115-125
Roy TA JJ Yang AI Krueger and CR Mackerer 1990 Percutaneous absorption of neat 2378-tetrachlorodibenzo-p-dioxin (TCDD) and TCDD sorbed on soils Toxicology 10( I )308
Sheppard SC 1995 Parameter values to model the soil ingestion pathway Environmental Monitoring and Assessment 3427-44
Tryphonas H S Hayward L OGrady JCK Loo DL Arnold F Bryce and ZZ Zawidzka 1989 Immunotoxicity studies of PCB (Aroclor 1254) in the adult rhesus (Macaco mulatto) monkey - Preliminary report Int J Immunoph 11 (2) 199-206
PrOLGEGEHOllSAT2m002VRESPCOMMHEAlSSllEALTPAR2wpltj laquo CHEMRlSK bullbull A DIVISION OF McLARENHART
Tiyphonas H MI Luster G Schiffinan LL Dawson M Hodgen D Germolec S Hayward F Bryce JCK Loo F Mandy and DL Arnold 199 la Effect ofchronic exposure of PCB (Aroclor 1254) on specific and nonspecific immune parameters in the rhesus (Macaca mulatto) monkey FundAppl Toxicol 16773-786
Tiyphonas H MI Luster KL White PH Naylor MR EKlos GR Burleson D Germolec M Hodgen S Hayward and DL Arnold 1991b Effects of PCB (Aroclorreg 1254) on non-specific immune parameters in rhesus (Macaca mulatto) monkeys Int Immunoph 13(6)639-648
Wester RC HI Maibach L Sedik and J Melendres 1993 Percutaneous absorption of PCBs from soil In vivo rhesus monkey in vitro human skin and biding to powdered human stratum corneum Journal of Toxicology and Environmental Health 39375-282
Piuj_GEGEHOLPSATU5raquo3 (raquo2RESPCOMMHEAJSSUEAJ_TPAR2 wpd CHEMRjISK1 bullbull A DIVISION OF MCLARENHART
ATTACHMENT B
SCHEDULE - HUMAN HEALTH FOR HOUSATONIC
Deliverable (vith explanatory notes) Due Date
1 Baekcalculated Risk-Based Concentrations (RBCs) for PCBs for Residential Scenario 30 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in soil for the residential scenario taking into account Attachment A ambient air and indoor dust exposures and the potential presence of a garden It will also present all exposure and toxicity parameter values used in deriving those RBCs In addition it will include an evaluation of exposures to PCBs from lawn mowing and a description of the methodology used in that evaluation
Backcaiculated RBCs for PCBs for Other Scenarios 60 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in the pertinent media for the scenarios described Attachment A beiow together with all exposure and toxicity parameter values used in deriving those RBCs
o General recreational o Canoeing Q Swimming o Dirt hiking o Current commercial use o Current agricultural use o Utility worker o Construction worker o Fish consumption (from recreational fishing)
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Deliverable (with explanatory notes) Lme uate
3 Proposal Addendum Regarding Useable Data Other COPCs and Other Biota January 30 1998
This subrnittal will present the results of andor proposals for several tasks in the risk assessment process
a Data evaluation This subrnittal will present the results of the data evaluation as described in Section 3 of the Risk Assessment Proposal and will include a summarization of useable data This evaluation will necessarily be based on available data and thus will not be able to take account of the results of any additional Phase IIRFI investigations that may be required by the Agencies The data evaluation is estimated to take approximately 2-3 months and must be completed before the selection of other (non-PCB) Chemicals of Potential Concern (COPCs) car- be conducted
b Proposal on other COPCs This subrnittal will also present a proposal regarding other (non-PCB) COPCs It will include
o Identification of other COPCs based on the data evaluation results and the selection criteria described in the Proposal (including comparison to upstream levels)
o Dose-response assessment and proposal of toxicity values for these COPCs o Proposal of RAFs and other chemical-specific exposure parameters for these COPCs o Identification of areas where these COPCs have been detected in concentrations exceeding
upstream levels and o Identification of pertinent exposure scenarios for those areas
These tasks will take approximately 2 months after completion of the data evaluation
c Proposal regarding consumption of other biota This submittal will further include a proposal for the evaluation of consumption of biota other than fish It will include a proposal as to the specific species to be evaluated the method of evaluation (quantitative or qualitative) and the parameter values to be used in the quantitative evaluations (Note This item may have to be postponed to a later date if GE has not received from the Agencies the results of the Univ of Mass fiddlehead fern study in the time for consideration prior to the due date for this subrnittal)
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Deliverable (with explanatory notes)
4 Backcalculated RBCs for Other COPCs for Relevant Scenarios
This subrnittal will present the backcalculated RBCs for the other identified COPCs in the pertinent media for the exposure scenarios identified as relevant to the areas where such COPCs have been detected It will also present all exposure and toxieity parameter values used in deriving those COPCs
Backcaiculated RBCs for Consumption of Other Biota
This subrnitta will present the backcalculated RBCs for the consumption of biota other than fish These RBCs win be presented for those species for which quantitative evaluation was conducted (The qualitative evaluation of other species will be included in the final risk assessment report)
6 Interim Risk Assessment Report - Application of RBCs Based on Current Use
This subrnkta will provide an Interim report on the risk assessment It will include a brief summary of the approach used and the prior submittals including the exposure scenarios and RBCs for each scenario It will also present sample forward risk calculations for each scenario using a dummy Exposure Point Concentration (EPC) It will further present the results of the application of the RBCs for PCBs (and other COPCs where applicable) to the relevant exposure points under current use assumptions This will include
o Identification of current uses of the site (by area) and the applicable exposure scenario based on such use o Identification of exposure points for each scenario based on current use o Calculation of EPCs for each exposure point (for PCBs and other COPCs where measured)
including a justification for the method of calculating them o Comparison of EPCs to applicable RBCs for each exposure point o Conclusion for each exposure point regarding presence of significant risk for applicable scenario and o Brief discussion of uncertainties and risk perspective
30 days from Agencies approval of proposal or- other COPCs (hern 3b)
30 days from Agencies approval of proposal for evaluation of consumption of other biota (Item 3c)
75 days from Agencies approval of Item 1 2 4 or 5 whichever is latest
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
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Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
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Andrew J Thomas Jr Esq GE Andrew T Silfer GE Ellen Ebert ChemRisk James R Bieke Shea amp Gardner James Nuss PE Blasland Bouck amp Lee Public Information Repositories - ECL I-R-IV(A)(1)
( with attachments)
ATTACHMENT A
PROPOSAL FOR ALTERNATIVE INPUT VALUES FOR THE HUMAN HEALTH RISK ASSESSMENT FOR THE HOUSATONIC RIVER
In accordance with the Agencies August 13 1997 comments on the Proposal for Human Health Risk Assessment for the Housatonic River General Electric Company (GE) proposes alternative input values for the following parameters (a) reference close (RfD) for reproductive and developmental effects of PCBs (b) enhanced soil ingestion rate for adult fanners and (c) dermal absorption factor for PCBs
Developmental RfD for PCBs
In Comment 10 of the final comments on the Proposal for Human Health Risk Assessment for the Housalonic River the Agencies stated that to evaluate developmental effects of PCBs GE should use the chronic RfD for Aroclor 1254 unless GE can provide a credible and relevant justification based on new data (not previously evaluated by EPA) for an alternative RfD for developmental effects Biased on new data that were not available at the time that EPA established its RfD for Aroclor 1254 CheniRisk has derived a RfD based on developmental efforts and GE proposes to use that value to evaluate such effects due to exposure of a pregnant female during the period of pregnancy
EPA published its current RfD for Aroclor 1254 (IRIS 1994) based on the dermal ocular and immunologic findings from a single study of rhesus monkeys reported by a number of researchers (Arnold et al 1993ab Tryphonas et al 1989 1991ab) In that study 16 adult female monkeys ingested gelatin capsules containing Aroclor 1254 at doses ranging from 0 to 80 ugkg-day for more than five years These monkeys achieved steady state after 25 months of exposure Preliminary results released by Arnold et al (1993ab) discussed the general health and clinical pathology evaluations of the adult monkeys that were conducted during the first 37 months of exposure Tryphonas et al (1989 1991ab) reported on the immunologic assessments of these monkeys after 23 and 55 months of exposure All of these evaluations were performed prior to the breeding phase of the study during which the monkeys were bred and the reproductive effects in the mothers and developmental effects in their offspring were evaluated Because the final results of the reproductive and developmental evaluations were not available at the time of the EPAs analysis these reproductive studies were not considered by the Agency in deriving its RfD for Aroclor 1254 (IRIS 1997)
Since the time that EPA established its RfD new data on the results of the breeding phase of the rhesus monkey study have become available Arnold et al (1995) completed their study of the reproductivedevelopmental impacts of PCBs on these monkeys and their offspring and published
ftigtLGEGEHOUSAT25laquoOU2RESPCOMMHEAlSSUEALTPAR2wplti CHEMRlSK - A DIVISION OF McLARENHART
their results in 1995 These data allow the derivation of an RfD that is specifically based on reproductive and developmental effects of Aroclor 1254 in rhesus monkeys
CheniRisk has developed such an RfD for use in the evaluation of subchronic exposures to a young woman during the nine months of her pregnancy in the relevant scenarios of the human health risk assessment for the Housatonic River Consistent with EPAs methodology in deriving RfDs from this group of studies several uncertainty factors have been applied to the lowest adverse effects level (LOAEL) of 0005 mgkg-day reported by Arnold et al (1995) to derive this RfD An uncertainty factor of 3 was used to account for interspecies extrapolation This uncertainly factor is appropriate due to the similarities in toxic responses and metabolism of PCBs by monkeys and humans and the general physiologic similarities between the species Another uncertainty factor of 3 was applied to account for the use of a LOAEL instead of a no adverse effect level (NOAEL) value This factor is appropriate because the effects observed in the young monkeys were not frank effects and are not necessarily adverse Finally an additional uncertainty factor of 10 was applied to account for interindividual variation or sensitivity within the population Application of the above safety factors results in a total uncertainty factor of 90 (3 x 3 x 10 == 90) which when applied to the LOAEL of 0005 mgkg-day results in a reproductivedeveloprnental RfD of 55 x 10s rngkg-day or 55 ngkgshyday
An additional uncertainty factor was not applied for translation from subchronic to chronic exposure duration because as DEP (1995) guidance recognizes exposure during nine months of pregnancy is a subchronic exposure scenario Moreover the actual overall exposure period for the adult female monkeys in the Arnold et al (1995) study (as in the prior studies from this group) was longer than one year and most of the adult monkeys had reached a steady stale body burden of PCBs before the studies of reproductive and developmental effects were initiated Hence the use of a subchronic exposure duration that is equivalent to the period of pregnancy (ie nine months) constitutes additional conservatism in the approach for assessing the developmental effects of PCBs
This subchronic RfD of 55 ngkg-day is a conservative estimate of the RfD in that it uses a safety factor of 10 to adjust for interindividual variation or sensitivity In fact because the RfD is based on effects in infant monkeys an already highly sensitive population a safety factor of 3 to account for interindividual variation among members of that sensitive subpopulation would be sufficient for developing an RfD In addition the study results appear to indicate that the infants may not have been more sensitive than the mothers as the changes observed in the infant monkeys were of similar or lesser severity than the maternal monkeys If a safety factor of 3 were used instead of the factor of 10 the result would be a total uncertainly factor of approximately 30 (3 x 3 x 3 == 27) resulting in a higher but still protective developmental RfD of 200 ngkg-day
Given the uncertainties associated with the derivation of an RfD for developmental effects GE has elected to take the more conservative approach and propose a subchronic developmental RfD of 55 x 10 mgkg-day for use in the Housatonic River risk assessment This value will be used to
PruLGDGEHOUSAT2593002RESKraquoMMHEAISSUEALTPAIU wpd - CHEMRlSK - A DIVISION OF McLARENHART
evaluate potential reproductive and developmental effects of PCBs in pregnant women and their offspring as a result of exposure during nine months of pregnancy in all scenarios for which this subchronic exposure scenario is proposed
Enhanced Soil Ingestion Rate for Adult Fanners
In Comment 56 of the final comments on the Proposal for Human Health Risk Assessment for the Housatonic River the Agencies stated that GE should use the DEP and EPA default enhanced soil ingestion rate of 480 nigday to evaluate potential soil ingestion exposures for the adult farmer unless it can provide a credible and relevant justification for an alternative rate
The current default enhanced ingestion rate of 480 mgday is an estimated rate of soil ingestion developed by Hawley (1985) based on his review of the soil ingestion literature available at that time While the estimates provided by Hawley have been used extensively to simulate high-end exposures via the soil ingestion pathway Hawleys estimates are not based on empirical data Rather Hawley derived his estimates based on assumptions about soildust levels on hands mouthing behavior and frequencies of indoor and outdoor activities According to the evaluation of soil ingestion studies conducted by EPA in preparing its August 1996 draft of the Exposure Factors Handbook Hawleys estimates must be considered conjectural due to the lack of supporting measurements
To derive his estimate of soil ingestion Hawley assumed that an adult while engaged in yard work or other physical activity would ingest the amount of soil that could coal the inside surface of the fingers and thumbs He estimated that soil could adhere to the skin at a rate of 35 mgcnr This estimated adherence factor was not measured rather it was based on the density of soil particles and Hawleys approximation of the depth of the layer of soil (50 pm) that might adhere to exposed skin on such an individual According to Sheppard (1995) Hawleys assumption of a 50 urn thick layer of soil on the arms and hands represents a very high and conspicuous soil load Sheppard reported that loads less than 1 mgcnr2 are more reasonable for making this calculation due to the fact that soil loads on the skin greater than 1 mgcm2 would be so noticeable that they would deter mouthing behavior until hands were washed or cleaned off
Since Hawleys approach was developed and Sheppard provided his evaluation of Hawleys approach new data on soil adherence have been published As reported by EPA (1996a) Kissel et al (1996) directly measured the soil loading on skin surfaces as a result of various occupational and recreational activities This study indicates that soil loadings vary with the type of activity and the body parts contacted As one would expect adherence appears to be greatest during outdoor activities such as farming and gardening and moire soildust tends to adhere to the hands and knees than to other areas of the body As measured by Kissel et al (1996) soil loadings for farmers hands range between 020 and 084 mgcm2 while adherence rates for other pants of their bodies are lower Values for other types of occupational exposures including irrigation workers and groundskeepers
ProuGEGEHOUSAT2mltX)2RESPCOMMlaquoEAISSUEALTPAR2wpd - CHEMRlSK - A DIVISION OF MCLARENHART
were measured to be less than 05 nigcnr In every case soil adherence during occupational exposures was measured to be considerably lower than Hawleys estimate of 35 mgcnr
In Dermal Exposure Assessment Principles and Applications (EPA 1992) 1EPA recommends a soil adherence range of 02 to 1 mgcm2 For typical exposure to outdoor soil DEP (1995) recommends a soil adherence value of 051 mgcnr2 All of these values are consistent with the adherence rates measured by Kissel et al (1996) suggesting that soil loadings greater than 10 mgcnr during outdoor activities such as fanning are not realistic
In addition it is unlikely that hand-to-mouth contact would occur at Hawleys estimated loading rate It is instead likely that individuals who have a soil loading of this magnitude would not pick up food or put their hands in their mouths before washing or wiping their hands to remove the excess soil
According to Sheppard (1995) it may be reasonable to assume that mouthing behavior could occur at a loading rate of 10 mgcnr As this loading rale is at the upper end of the range of soil loading rates supported by both EPA and DEP and is higher than the highest soil loading rates reported by Kissel et al for the hands of farmers or any other adult exposure this soil loading rate has been used in combination with Hawleys other assumptions to derive an enhanced soil ingestion rate for farmers
If one substitutes the value of 10 mgcm2 for Hawleys assumption of 35 mgcm2 and continues to use Hawleys other exposure assumptions the resulting enhanced outdoor soil ingestion rate is 137 nigday For the purposes of the Housatonic River risk assessment GE proposes to use this more empirically-based enhanced adult soil ingestion rate of 137 ingday for the adult fanner
Derma] Absorption Rate for PCBs
In Comment 62 of their final comments on the Proposal for Human Health Risk Assessment for the Housatonic River the Agencies stated that they disagree with the use of dermal ilbsorption values of 146 percent and 143 percent proposed by GE for soils and sediment respectively The Agencies reconinnended instead that GE use a dermal absorption factor of 14 percent unless GE provides a credible and relevant justification for an alternative dermal absorption factor GE believes that a dermal absorption factor of 14 percent is not justifiable for the Housatonic River risk assessment due to limitations of the study upon which it is based and site-specific factors that indicate that such an estimate likely overstates actual absorption of PCBs from soils and sediments at this site
The dermal absorption values originally proposed by GE for soils and sediment were calculated by ChemRisk based on data from Roy et al (1990) As discussed in detail in the EPAs (1992) Dermal Exposure Assessment Guidance Principles and Applications Roy et al (1990) studied percutaneous absorption of tetrachlorobiphenyl (TCB) through human skin (in vitro) TCB was applied to human skin for 96 hours at a concentration of 1000 rngkg in soil with a low (045
Prni_GEGEHOUSAT2SW 002RESPCOMMHEAISSlEALTPA]U wpd 4 CHEMRlSK bullbullA DIVISION OF IVICL AH ENHART
percent) organic carbon content Absorption through human skin was 736 percent after 96 hours of exposure but negligible after only eight hours of exposure Roy et al (1990) also studied absorption from soil by rat skin in vitro and in vivo Total in vitro absorption from high (1122 percent) organic carbon content soil over 96 hours was 964 percent while absorption from low organic carbon soil in vitro in rats was 3195 percent over 96 hours For low organic carbon soil the absorption for the rat in vivo was 497 percent absorption after 96 hours
In its analysis EPA (1992) adjusted the Roy et al data to derive estimates of in vivo absorption of TCB in humans based on 24-hour exposure This was accomplished by adjusting the data to reflect differences between in vitro and in vivo tests rat and human skin and organic carbon content of the soil The adjusted percent TCB absorbed from soil was estimated to range from 063 percent for soil with high organic carbon content to 21 percent for soil with low organic carbon content Considering the uncertainty in these estimates EPA (1992) recommended a range of 06 percent to 6 percent for the percent of TCB dermally absorbed from the soil Moreover by comparing the Roy et al (1990) data to in vivo data from other bioavailability studies using other PCBs EPA (1992) concluded that the uptake of TCB was similar to that of other PCBs and that the range of 06 percent to 6 percent absorption for TCB is generally appropriate for PCBs
As these data indicate the dermal absorption of PCBs in soil is highly dependent on the organic carbon content of the soil GE proposed to account for this dependency by extrapolating from the Roy et al data to the relatively high site-specific organic carbon content of soils and sediments at the site DEP (1993) had previously agreed that it was appropriate to derive dermal absorption factors based on site-specific organic carbon content data as long as the organic carbon values used were based on reliable dala Because there are substantial data on the organic carbon contents of site soils and sediments GE proposed to use site-specific dermal absorption factors based on extrapolations of the Roy et al (1990) findings
In Comment 62 the Agencies stated that they no longer support the site-specific dermal absorption values previously derived by GE due to the findings of a study by Wester et al (1993) which indicated that dermal absorption of PCBs may be higher than that estimated by EPA using the Roy et al (1990) data The Wester et al (1993) study was designed to measure the extent to which Aroclors 1242 and 1254 would partition out of soil and be absorbed through the skin Wester et al (1993) added radio-labeled Aroclor 1242 and Aroclor 1234 to soil containing 26 percent sand 26 percent clay 48 percent silt and 09 percent organic carbon content Soils were mixed by hand to final concentrations of 44 mgkg Aroclor 1242 and 23 mgkg Aroclor 1254 These soils were then applied to the clipped abdominal skin of adult female rhesus monkeys for a period of 24 hours in a manner that would prevent the animals from licking or scratching at the skirt and would prevent exfoliated skin from contaminating urine or feces The skin site was covered with a non-occlusive cover that permitted air and moisture to move freely to and from the skin but retained the soil at the application site Urine and feces were collected during the exposure period After 24 hours skin
Proi_GEGEHOVSArumW2MSPCOMMVHEAISSUEALTPARiwpltl bull CHEMRlSK - A DIVISION OF MCLARENHART
was washed and urine and feces were periodically measured and analyzed for PCBs for 34 days following exposure
Percutaneous absorption was determined by urinary and fecal excretion following topical and intravenous administration Based on their measured recoveries combined with excretion efficiency data previously measured at their laboratory Wester et al (1993) concluded that the percutaneous absorptions of Aroclor 1242 and Aroclor 1254 from soil were 138 plusmn 27 percent and 141 + 10 percent of dose respectively Recovery of PCBs from skin was 83 percent for Aroclor 1242 and 72 percent for Aroclor 1254 most of the recovered dose was in the residual soil indicating that the PCBs had remained bound to soil during that 24-hour period rather than adsorbing to skin
While the Wester et al (1993) study was a well-conducted study that used appropriate experimental methodology there are several aspects of the study that limit its usefulness as a basis for developing dermal absorption factors for this site-specific risk assessment First Wester et al (1993) evaluated soils that had an organic carbon content of 09 percent and they did not test for variations in dermal absorption from soils with higher organic carbon contents This organic carbon content is very low and is not consistent with the levels of organic carbon content found in soils and sediments of the Housatonic River and its floodplain (ranging from 01 - 26 percent with arithmetic means of 50 and 53 percent for soils and sediments respectively) It is likely based on the clear trends shown in the Roy et al (1990) data that if higher levels of organic carbon had been tested by Wester et al (1993) the result would have been lower levels of percutaneous absorption
Second Wester et al (1993) applied soil to the animals skin at a rate of 40 ing soilcm2 skin (resulting in PCB concentrations on the skin of 175 ug PCBcm for Aroclor 1242 and 091 pg PCBcm2 for Aroclor 1254) This application rate is substantially greater than the adherence rates measured by Kissel et al (1996) or considered appropriate by DEP or EPA This higher rate of application may have increased the absorption of PCBs through the skin
Third the study used freshly spiked commercial PCB mixtures As discussed by EPA (1996b) in its reassessment of the carcinogenic potential of environmental PCB mixtures the composition of PCB mixtures changes over time through differential partitioning and chemical transformation of the component congeners For example congeners of lower chlorine content tend to be more volatile and also more soluble in water with rates of vaporization and relative water solubilities varying over several orders of magnitude between congeners These processes of volatilization and dissolution would appear to reduce the relative dermal absorption of a weathered PCB mixture compared to that of a freshly spiked sample In addition a weathered PCB mixture should form a tighter affinity to an environmental soil matrix over time further reducing its availability to become dermally absorbed
Finally Guy and Hadgraft (1987) reported that the permeability of skin in various parts of the body may be highly variable They reported that studies of hydrocortisone malathion and parathion have
ProjJ3DGEHOUSATU5laquoU02RESKOMMHEAISSUEALTPARlwpd - CHEMRlSK - A DIVISION OF McLARENHART
indicated that absorption across leg and forearm skin is similar but that the skin of the trunk is 25 times more permeable than the skin of the forearm or leg If this is also the case for PCBs it may be reasonable to conclude that absorption through the abdominal skin of the Wester at al (1993) monkeys may overestimate absorption through the skin of the arms or legs by as much as a factor of 25 If this were shown to be the case the result would be a dermal absorption of approximately 6 percent similar to the absorption factor recommended by EPA (1992) based on the Roy et al (1990) study for low carbon content soils over 24 hours of exposure
While the Wester et al (1993) study was a well conducted study the above-outlined limitations and uncertainties undermine its usefulness for this site-specific risk assessment In addition EPA has convened a dermal workgroup to evaluate the dermal absorption of PCBs and make recommendations for a revised absorption factor if appropriate This work group has not yet made a final recommendation When the work group has finished its analysis and EPA makes a recommendation on this issue GE will review that recommendation and all available data on dermal absorption of PCBs If however such a recommendation has not been made by the time that the risk assessment is conducted GE proposes to use the upper bound of current Agency guidance 6 percent for the evaluation of dermal absorption of PCBs from soil and sediment
References
Arnold DL F Bryce R Stapley PP McGuire D Burns JR Tanner and K Karpinski 1993a lexicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part 1A Prebreeding phase - clinical health findings Fd Chem Toxicol 31799-810
Arnold DL F Bryce K Karpinski J Mes S Fernie H Tryphonas J Truelove PP McGuire D Burns JR Tanner R Stapley ZZ Zawidzka and D Basford 1993b Toxicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part IB Prebreeding phase - clinical and analytical laboratory findings Fd Chem Toxicol 31811-824
Arnold D L F Bryce PP McGuire R Stapley JR Tanner E Wrenshall J Mes S Fernie H Tryphonas S Hayward and S Malcolm 1995 Toxicological consequences of Aroclor 1254 ingestion by female rhesus (Macaco mulatto) monkeys Part 2 Reproduction and infant findings Fd Chem Toxicol 33(6)457-474
DEP 1995 Guidance for Disposal Site Risk Characterization - In Support of the Massachusetts Contingency Plan - Interim Final Policy Massachusetts Department of Environmental Protection Bureau of Waste Site Cleanup and Office of Research and Standards Boston MA WSCORS-95shy141 July
DEP 1993 Memorandum to Catherine Wanat Project Manager WEROfrom Meg Harvey ORS Re Review of Revised Risk Assessment to Evaluate Need for Short-Term Measures in the 10-Year
ProjJDEGEHOliSATU5raquo3002RESrcOMMHEAISSUEALTPAIUwpltl CHEMRlSK - A DIVISION OF McLARENHART
Floodplain of the Housatonic River Massachusetts Department of Environmental Protection Office of Research and Standards Boston MA August 5
EFA 1996a Exposure Factors Handbook Volume I of III General Factors - Review Draft US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-95002Ba August
EPA 1996b Proposed Guidelines for Carcinogen Risk Assessment US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-92003C April
EPA 1992Dermal Exposure Assessment Principles and Applications US Environmental Protection Agency Office of Research and Development Washington DC EPA6008-9101 IB January
Guy RH and J Hadgraft 1987 Principles of skin permeability relevant to chemical exposure PB89-130009 NIOSH Grant K01-OH-00017 National Technical Information Service US Department of Commerce Springfield VA
Hawley JK 1985 Assessment of health risk from exposure to contaminated soil Risk Analysis 5289-302
IRIS 1997 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
IRIS 1994 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
Kissel JC KY Richter and RA Fenske 1996 Field measurement of dermal soil loading attributable to various activities Implications for exposure assessment Risk Anal 16 (1) 115-125
Roy TA JJ Yang AI Krueger and CR Mackerer 1990 Percutaneous absorption of neat 2378-tetrachlorodibenzo-p-dioxin (TCDD) and TCDD sorbed on soils Toxicology 10( I )308
Sheppard SC 1995 Parameter values to model the soil ingestion pathway Environmental Monitoring and Assessment 3427-44
Tryphonas H S Hayward L OGrady JCK Loo DL Arnold F Bryce and ZZ Zawidzka 1989 Immunotoxicity studies of PCB (Aroclor 1254) in the adult rhesus (Macaco mulatto) monkey - Preliminary report Int J Immunoph 11 (2) 199-206
PrOLGEGEHOllSAT2m002VRESPCOMMHEAlSSllEALTPAR2wpltj laquo CHEMRlSK bullbull A DIVISION OF McLARENHART
Tiyphonas H MI Luster G Schiffinan LL Dawson M Hodgen D Germolec S Hayward F Bryce JCK Loo F Mandy and DL Arnold 199 la Effect ofchronic exposure of PCB (Aroclor 1254) on specific and nonspecific immune parameters in the rhesus (Macaca mulatto) monkey FundAppl Toxicol 16773-786
Tiyphonas H MI Luster KL White PH Naylor MR EKlos GR Burleson D Germolec M Hodgen S Hayward and DL Arnold 1991b Effects of PCB (Aroclorreg 1254) on non-specific immune parameters in rhesus (Macaca mulatto) monkeys Int Immunoph 13(6)639-648
Wester RC HI Maibach L Sedik and J Melendres 1993 Percutaneous absorption of PCBs from soil In vivo rhesus monkey in vitro human skin and biding to powdered human stratum corneum Journal of Toxicology and Environmental Health 39375-282
Piuj_GEGEHOLPSATU5raquo3 (raquo2RESPCOMMHEAJSSUEAJ_TPAR2 wpd CHEMRjISK1 bullbull A DIVISION OF MCLARENHART
ATTACHMENT B
SCHEDULE - HUMAN HEALTH FOR HOUSATONIC
Deliverable (vith explanatory notes) Due Date
1 Baekcalculated Risk-Based Concentrations (RBCs) for PCBs for Residential Scenario 30 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in soil for the residential scenario taking into account Attachment A ambient air and indoor dust exposures and the potential presence of a garden It will also present all exposure and toxicity parameter values used in deriving those RBCs In addition it will include an evaluation of exposures to PCBs from lawn mowing and a description of the methodology used in that evaluation
Backcaiculated RBCs for PCBs for Other Scenarios 60 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in the pertinent media for the scenarios described Attachment A beiow together with all exposure and toxicity parameter values used in deriving those RBCs
o General recreational o Canoeing Q Swimming o Dirt hiking o Current commercial use o Current agricultural use o Utility worker o Construction worker o Fish consumption (from recreational fishing)
- 2 shy
Deliverable (with explanatory notes) Lme uate
3 Proposal Addendum Regarding Useable Data Other COPCs and Other Biota January 30 1998
This subrnittal will present the results of andor proposals for several tasks in the risk assessment process
a Data evaluation This subrnittal will present the results of the data evaluation as described in Section 3 of the Risk Assessment Proposal and will include a summarization of useable data This evaluation will necessarily be based on available data and thus will not be able to take account of the results of any additional Phase IIRFI investigations that may be required by the Agencies The data evaluation is estimated to take approximately 2-3 months and must be completed before the selection of other (non-PCB) Chemicals of Potential Concern (COPCs) car- be conducted
b Proposal on other COPCs This subrnittal will also present a proposal regarding other (non-PCB) COPCs It will include
o Identification of other COPCs based on the data evaluation results and the selection criteria described in the Proposal (including comparison to upstream levels)
o Dose-response assessment and proposal of toxicity values for these COPCs o Proposal of RAFs and other chemical-specific exposure parameters for these COPCs o Identification of areas where these COPCs have been detected in concentrations exceeding
upstream levels and o Identification of pertinent exposure scenarios for those areas
These tasks will take approximately 2 months after completion of the data evaluation
c Proposal regarding consumption of other biota This submittal will further include a proposal for the evaluation of consumption of biota other than fish It will include a proposal as to the specific species to be evaluated the method of evaluation (quantitative or qualitative) and the parameter values to be used in the quantitative evaluations (Note This item may have to be postponed to a later date if GE has not received from the Agencies the results of the Univ of Mass fiddlehead fern study in the time for consideration prior to the due date for this subrnittal)
-3 shy
Deliverable (with explanatory notes)
4 Backcalculated RBCs for Other COPCs for Relevant Scenarios
This subrnittal will present the backcalculated RBCs for the other identified COPCs in the pertinent media for the exposure scenarios identified as relevant to the areas where such COPCs have been detected It will also present all exposure and toxieity parameter values used in deriving those COPCs
Backcaiculated RBCs for Consumption of Other Biota
This subrnitta will present the backcalculated RBCs for the consumption of biota other than fish These RBCs win be presented for those species for which quantitative evaluation was conducted (The qualitative evaluation of other species will be included in the final risk assessment report)
6 Interim Risk Assessment Report - Application of RBCs Based on Current Use
This subrnkta will provide an Interim report on the risk assessment It will include a brief summary of the approach used and the prior submittals including the exposure scenarios and RBCs for each scenario It will also present sample forward risk calculations for each scenario using a dummy Exposure Point Concentration (EPC) It will further present the results of the application of the RBCs for PCBs (and other COPCs where applicable) to the relevant exposure points under current use assumptions This will include
o Identification of current uses of the site (by area) and the applicable exposure scenario based on such use o Identification of exposure points for each scenario based on current use o Calculation of EPCs for each exposure point (for PCBs and other COPCs where measured)
including a justification for the method of calculating them o Comparison of EPCs to applicable RBCs for each exposure point o Conclusion for each exposure point regarding presence of significant risk for applicable scenario and o Brief discussion of uncertainties and risk perspective
30 days from Agencies approval of proposal or- other COPCs (hern 3b)
30 days from Agencies approval of proposal for evaluation of consumption of other biota (Item 3c)
75 days from Agencies approval of Item 1 2 4 or 5 whichever is latest
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
- 5 shy
Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
ATTACHMENT A
PROPOSAL FOR ALTERNATIVE INPUT VALUES FOR THE HUMAN HEALTH RISK ASSESSMENT FOR THE HOUSATONIC RIVER
In accordance with the Agencies August 13 1997 comments on the Proposal for Human Health Risk Assessment for the Housatonic River General Electric Company (GE) proposes alternative input values for the following parameters (a) reference close (RfD) for reproductive and developmental effects of PCBs (b) enhanced soil ingestion rate for adult fanners and (c) dermal absorption factor for PCBs
Developmental RfD for PCBs
In Comment 10 of the final comments on the Proposal for Human Health Risk Assessment for the Housalonic River the Agencies stated that to evaluate developmental effects of PCBs GE should use the chronic RfD for Aroclor 1254 unless GE can provide a credible and relevant justification based on new data (not previously evaluated by EPA) for an alternative RfD for developmental effects Biased on new data that were not available at the time that EPA established its RfD for Aroclor 1254 CheniRisk has derived a RfD based on developmental efforts and GE proposes to use that value to evaluate such effects due to exposure of a pregnant female during the period of pregnancy
EPA published its current RfD for Aroclor 1254 (IRIS 1994) based on the dermal ocular and immunologic findings from a single study of rhesus monkeys reported by a number of researchers (Arnold et al 1993ab Tryphonas et al 1989 1991ab) In that study 16 adult female monkeys ingested gelatin capsules containing Aroclor 1254 at doses ranging from 0 to 80 ugkg-day for more than five years These monkeys achieved steady state after 25 months of exposure Preliminary results released by Arnold et al (1993ab) discussed the general health and clinical pathology evaluations of the adult monkeys that were conducted during the first 37 months of exposure Tryphonas et al (1989 1991ab) reported on the immunologic assessments of these monkeys after 23 and 55 months of exposure All of these evaluations were performed prior to the breeding phase of the study during which the monkeys were bred and the reproductive effects in the mothers and developmental effects in their offspring were evaluated Because the final results of the reproductive and developmental evaluations were not available at the time of the EPAs analysis these reproductive studies were not considered by the Agency in deriving its RfD for Aroclor 1254 (IRIS 1997)
Since the time that EPA established its RfD new data on the results of the breeding phase of the rhesus monkey study have become available Arnold et al (1995) completed their study of the reproductivedevelopmental impacts of PCBs on these monkeys and their offspring and published
ftigtLGEGEHOUSAT25laquoOU2RESPCOMMHEAlSSUEALTPAR2wplti CHEMRlSK - A DIVISION OF McLARENHART
their results in 1995 These data allow the derivation of an RfD that is specifically based on reproductive and developmental effects of Aroclor 1254 in rhesus monkeys
CheniRisk has developed such an RfD for use in the evaluation of subchronic exposures to a young woman during the nine months of her pregnancy in the relevant scenarios of the human health risk assessment for the Housatonic River Consistent with EPAs methodology in deriving RfDs from this group of studies several uncertainty factors have been applied to the lowest adverse effects level (LOAEL) of 0005 mgkg-day reported by Arnold et al (1995) to derive this RfD An uncertainty factor of 3 was used to account for interspecies extrapolation This uncertainly factor is appropriate due to the similarities in toxic responses and metabolism of PCBs by monkeys and humans and the general physiologic similarities between the species Another uncertainty factor of 3 was applied to account for the use of a LOAEL instead of a no adverse effect level (NOAEL) value This factor is appropriate because the effects observed in the young monkeys were not frank effects and are not necessarily adverse Finally an additional uncertainty factor of 10 was applied to account for interindividual variation or sensitivity within the population Application of the above safety factors results in a total uncertainty factor of 90 (3 x 3 x 10 == 90) which when applied to the LOAEL of 0005 mgkg-day results in a reproductivedeveloprnental RfD of 55 x 10s rngkg-day or 55 ngkgshyday
An additional uncertainty factor was not applied for translation from subchronic to chronic exposure duration because as DEP (1995) guidance recognizes exposure during nine months of pregnancy is a subchronic exposure scenario Moreover the actual overall exposure period for the adult female monkeys in the Arnold et al (1995) study (as in the prior studies from this group) was longer than one year and most of the adult monkeys had reached a steady stale body burden of PCBs before the studies of reproductive and developmental effects were initiated Hence the use of a subchronic exposure duration that is equivalent to the period of pregnancy (ie nine months) constitutes additional conservatism in the approach for assessing the developmental effects of PCBs
This subchronic RfD of 55 ngkg-day is a conservative estimate of the RfD in that it uses a safety factor of 10 to adjust for interindividual variation or sensitivity In fact because the RfD is based on effects in infant monkeys an already highly sensitive population a safety factor of 3 to account for interindividual variation among members of that sensitive subpopulation would be sufficient for developing an RfD In addition the study results appear to indicate that the infants may not have been more sensitive than the mothers as the changes observed in the infant monkeys were of similar or lesser severity than the maternal monkeys If a safety factor of 3 were used instead of the factor of 10 the result would be a total uncertainly factor of approximately 30 (3 x 3 x 3 == 27) resulting in a higher but still protective developmental RfD of 200 ngkg-day
Given the uncertainties associated with the derivation of an RfD for developmental effects GE has elected to take the more conservative approach and propose a subchronic developmental RfD of 55 x 10 mgkg-day for use in the Housatonic River risk assessment This value will be used to
PruLGDGEHOUSAT2593002RESKraquoMMHEAISSUEALTPAIU wpd - CHEMRlSK - A DIVISION OF McLARENHART
evaluate potential reproductive and developmental effects of PCBs in pregnant women and their offspring as a result of exposure during nine months of pregnancy in all scenarios for which this subchronic exposure scenario is proposed
Enhanced Soil Ingestion Rate for Adult Fanners
In Comment 56 of the final comments on the Proposal for Human Health Risk Assessment for the Housatonic River the Agencies stated that GE should use the DEP and EPA default enhanced soil ingestion rate of 480 nigday to evaluate potential soil ingestion exposures for the adult farmer unless it can provide a credible and relevant justification for an alternative rate
The current default enhanced ingestion rate of 480 mgday is an estimated rate of soil ingestion developed by Hawley (1985) based on his review of the soil ingestion literature available at that time While the estimates provided by Hawley have been used extensively to simulate high-end exposures via the soil ingestion pathway Hawleys estimates are not based on empirical data Rather Hawley derived his estimates based on assumptions about soildust levels on hands mouthing behavior and frequencies of indoor and outdoor activities According to the evaluation of soil ingestion studies conducted by EPA in preparing its August 1996 draft of the Exposure Factors Handbook Hawleys estimates must be considered conjectural due to the lack of supporting measurements
To derive his estimate of soil ingestion Hawley assumed that an adult while engaged in yard work or other physical activity would ingest the amount of soil that could coal the inside surface of the fingers and thumbs He estimated that soil could adhere to the skin at a rate of 35 mgcnr This estimated adherence factor was not measured rather it was based on the density of soil particles and Hawleys approximation of the depth of the layer of soil (50 pm) that might adhere to exposed skin on such an individual According to Sheppard (1995) Hawleys assumption of a 50 urn thick layer of soil on the arms and hands represents a very high and conspicuous soil load Sheppard reported that loads less than 1 mgcnr2 are more reasonable for making this calculation due to the fact that soil loads on the skin greater than 1 mgcm2 would be so noticeable that they would deter mouthing behavior until hands were washed or cleaned off
Since Hawleys approach was developed and Sheppard provided his evaluation of Hawleys approach new data on soil adherence have been published As reported by EPA (1996a) Kissel et al (1996) directly measured the soil loading on skin surfaces as a result of various occupational and recreational activities This study indicates that soil loadings vary with the type of activity and the body parts contacted As one would expect adherence appears to be greatest during outdoor activities such as farming and gardening and moire soildust tends to adhere to the hands and knees than to other areas of the body As measured by Kissel et al (1996) soil loadings for farmers hands range between 020 and 084 mgcm2 while adherence rates for other pants of their bodies are lower Values for other types of occupational exposures including irrigation workers and groundskeepers
ProuGEGEHOUSAT2mltX)2RESPCOMMlaquoEAISSUEALTPAR2wpd - CHEMRlSK - A DIVISION OF MCLARENHART
were measured to be less than 05 nigcnr In every case soil adherence during occupational exposures was measured to be considerably lower than Hawleys estimate of 35 mgcnr
In Dermal Exposure Assessment Principles and Applications (EPA 1992) 1EPA recommends a soil adherence range of 02 to 1 mgcm2 For typical exposure to outdoor soil DEP (1995) recommends a soil adherence value of 051 mgcnr2 All of these values are consistent with the adherence rates measured by Kissel et al (1996) suggesting that soil loadings greater than 10 mgcnr during outdoor activities such as fanning are not realistic
In addition it is unlikely that hand-to-mouth contact would occur at Hawleys estimated loading rate It is instead likely that individuals who have a soil loading of this magnitude would not pick up food or put their hands in their mouths before washing or wiping their hands to remove the excess soil
According to Sheppard (1995) it may be reasonable to assume that mouthing behavior could occur at a loading rate of 10 mgcnr As this loading rale is at the upper end of the range of soil loading rates supported by both EPA and DEP and is higher than the highest soil loading rates reported by Kissel et al for the hands of farmers or any other adult exposure this soil loading rate has been used in combination with Hawleys other assumptions to derive an enhanced soil ingestion rate for farmers
If one substitutes the value of 10 mgcm2 for Hawleys assumption of 35 mgcm2 and continues to use Hawleys other exposure assumptions the resulting enhanced outdoor soil ingestion rate is 137 nigday For the purposes of the Housatonic River risk assessment GE proposes to use this more empirically-based enhanced adult soil ingestion rate of 137 ingday for the adult fanner
Derma] Absorption Rate for PCBs
In Comment 62 of their final comments on the Proposal for Human Health Risk Assessment for the Housatonic River the Agencies stated that they disagree with the use of dermal ilbsorption values of 146 percent and 143 percent proposed by GE for soils and sediment respectively The Agencies reconinnended instead that GE use a dermal absorption factor of 14 percent unless GE provides a credible and relevant justification for an alternative dermal absorption factor GE believes that a dermal absorption factor of 14 percent is not justifiable for the Housatonic River risk assessment due to limitations of the study upon which it is based and site-specific factors that indicate that such an estimate likely overstates actual absorption of PCBs from soils and sediments at this site
The dermal absorption values originally proposed by GE for soils and sediment were calculated by ChemRisk based on data from Roy et al (1990) As discussed in detail in the EPAs (1992) Dermal Exposure Assessment Guidance Principles and Applications Roy et al (1990) studied percutaneous absorption of tetrachlorobiphenyl (TCB) through human skin (in vitro) TCB was applied to human skin for 96 hours at a concentration of 1000 rngkg in soil with a low (045
Prni_GEGEHOUSAT2SW 002RESPCOMMHEAISSlEALTPA]U wpd 4 CHEMRlSK bullbullA DIVISION OF IVICL AH ENHART
percent) organic carbon content Absorption through human skin was 736 percent after 96 hours of exposure but negligible after only eight hours of exposure Roy et al (1990) also studied absorption from soil by rat skin in vitro and in vivo Total in vitro absorption from high (1122 percent) organic carbon content soil over 96 hours was 964 percent while absorption from low organic carbon soil in vitro in rats was 3195 percent over 96 hours For low organic carbon soil the absorption for the rat in vivo was 497 percent absorption after 96 hours
In its analysis EPA (1992) adjusted the Roy et al data to derive estimates of in vivo absorption of TCB in humans based on 24-hour exposure This was accomplished by adjusting the data to reflect differences between in vitro and in vivo tests rat and human skin and organic carbon content of the soil The adjusted percent TCB absorbed from soil was estimated to range from 063 percent for soil with high organic carbon content to 21 percent for soil with low organic carbon content Considering the uncertainty in these estimates EPA (1992) recommended a range of 06 percent to 6 percent for the percent of TCB dermally absorbed from the soil Moreover by comparing the Roy et al (1990) data to in vivo data from other bioavailability studies using other PCBs EPA (1992) concluded that the uptake of TCB was similar to that of other PCBs and that the range of 06 percent to 6 percent absorption for TCB is generally appropriate for PCBs
As these data indicate the dermal absorption of PCBs in soil is highly dependent on the organic carbon content of the soil GE proposed to account for this dependency by extrapolating from the Roy et al data to the relatively high site-specific organic carbon content of soils and sediments at the site DEP (1993) had previously agreed that it was appropriate to derive dermal absorption factors based on site-specific organic carbon content data as long as the organic carbon values used were based on reliable dala Because there are substantial data on the organic carbon contents of site soils and sediments GE proposed to use site-specific dermal absorption factors based on extrapolations of the Roy et al (1990) findings
In Comment 62 the Agencies stated that they no longer support the site-specific dermal absorption values previously derived by GE due to the findings of a study by Wester et al (1993) which indicated that dermal absorption of PCBs may be higher than that estimated by EPA using the Roy et al (1990) data The Wester et al (1993) study was designed to measure the extent to which Aroclors 1242 and 1254 would partition out of soil and be absorbed through the skin Wester et al (1993) added radio-labeled Aroclor 1242 and Aroclor 1234 to soil containing 26 percent sand 26 percent clay 48 percent silt and 09 percent organic carbon content Soils were mixed by hand to final concentrations of 44 mgkg Aroclor 1242 and 23 mgkg Aroclor 1254 These soils were then applied to the clipped abdominal skin of adult female rhesus monkeys for a period of 24 hours in a manner that would prevent the animals from licking or scratching at the skirt and would prevent exfoliated skin from contaminating urine or feces The skin site was covered with a non-occlusive cover that permitted air and moisture to move freely to and from the skin but retained the soil at the application site Urine and feces were collected during the exposure period After 24 hours skin
Proi_GEGEHOVSArumW2MSPCOMMVHEAISSUEALTPARiwpltl bull CHEMRlSK - A DIVISION OF MCLARENHART
was washed and urine and feces were periodically measured and analyzed for PCBs for 34 days following exposure
Percutaneous absorption was determined by urinary and fecal excretion following topical and intravenous administration Based on their measured recoveries combined with excretion efficiency data previously measured at their laboratory Wester et al (1993) concluded that the percutaneous absorptions of Aroclor 1242 and Aroclor 1254 from soil were 138 plusmn 27 percent and 141 + 10 percent of dose respectively Recovery of PCBs from skin was 83 percent for Aroclor 1242 and 72 percent for Aroclor 1254 most of the recovered dose was in the residual soil indicating that the PCBs had remained bound to soil during that 24-hour period rather than adsorbing to skin
While the Wester et al (1993) study was a well-conducted study that used appropriate experimental methodology there are several aspects of the study that limit its usefulness as a basis for developing dermal absorption factors for this site-specific risk assessment First Wester et al (1993) evaluated soils that had an organic carbon content of 09 percent and they did not test for variations in dermal absorption from soils with higher organic carbon contents This organic carbon content is very low and is not consistent with the levels of organic carbon content found in soils and sediments of the Housatonic River and its floodplain (ranging from 01 - 26 percent with arithmetic means of 50 and 53 percent for soils and sediments respectively) It is likely based on the clear trends shown in the Roy et al (1990) data that if higher levels of organic carbon had been tested by Wester et al (1993) the result would have been lower levels of percutaneous absorption
Second Wester et al (1993) applied soil to the animals skin at a rate of 40 ing soilcm2 skin (resulting in PCB concentrations on the skin of 175 ug PCBcm for Aroclor 1242 and 091 pg PCBcm2 for Aroclor 1254) This application rate is substantially greater than the adherence rates measured by Kissel et al (1996) or considered appropriate by DEP or EPA This higher rate of application may have increased the absorption of PCBs through the skin
Third the study used freshly spiked commercial PCB mixtures As discussed by EPA (1996b) in its reassessment of the carcinogenic potential of environmental PCB mixtures the composition of PCB mixtures changes over time through differential partitioning and chemical transformation of the component congeners For example congeners of lower chlorine content tend to be more volatile and also more soluble in water with rates of vaporization and relative water solubilities varying over several orders of magnitude between congeners These processes of volatilization and dissolution would appear to reduce the relative dermal absorption of a weathered PCB mixture compared to that of a freshly spiked sample In addition a weathered PCB mixture should form a tighter affinity to an environmental soil matrix over time further reducing its availability to become dermally absorbed
Finally Guy and Hadgraft (1987) reported that the permeability of skin in various parts of the body may be highly variable They reported that studies of hydrocortisone malathion and parathion have
ProjJ3DGEHOUSATU5laquoU02RESKOMMHEAISSUEALTPARlwpd - CHEMRlSK - A DIVISION OF McLARENHART
indicated that absorption across leg and forearm skin is similar but that the skin of the trunk is 25 times more permeable than the skin of the forearm or leg If this is also the case for PCBs it may be reasonable to conclude that absorption through the abdominal skin of the Wester at al (1993) monkeys may overestimate absorption through the skin of the arms or legs by as much as a factor of 25 If this were shown to be the case the result would be a dermal absorption of approximately 6 percent similar to the absorption factor recommended by EPA (1992) based on the Roy et al (1990) study for low carbon content soils over 24 hours of exposure
While the Wester et al (1993) study was a well conducted study the above-outlined limitations and uncertainties undermine its usefulness for this site-specific risk assessment In addition EPA has convened a dermal workgroup to evaluate the dermal absorption of PCBs and make recommendations for a revised absorption factor if appropriate This work group has not yet made a final recommendation When the work group has finished its analysis and EPA makes a recommendation on this issue GE will review that recommendation and all available data on dermal absorption of PCBs If however such a recommendation has not been made by the time that the risk assessment is conducted GE proposes to use the upper bound of current Agency guidance 6 percent for the evaluation of dermal absorption of PCBs from soil and sediment
References
Arnold DL F Bryce R Stapley PP McGuire D Burns JR Tanner and K Karpinski 1993a lexicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part 1A Prebreeding phase - clinical health findings Fd Chem Toxicol 31799-810
Arnold DL F Bryce K Karpinski J Mes S Fernie H Tryphonas J Truelove PP McGuire D Burns JR Tanner R Stapley ZZ Zawidzka and D Basford 1993b Toxicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part IB Prebreeding phase - clinical and analytical laboratory findings Fd Chem Toxicol 31811-824
Arnold D L F Bryce PP McGuire R Stapley JR Tanner E Wrenshall J Mes S Fernie H Tryphonas S Hayward and S Malcolm 1995 Toxicological consequences of Aroclor 1254 ingestion by female rhesus (Macaco mulatto) monkeys Part 2 Reproduction and infant findings Fd Chem Toxicol 33(6)457-474
DEP 1995 Guidance for Disposal Site Risk Characterization - In Support of the Massachusetts Contingency Plan - Interim Final Policy Massachusetts Department of Environmental Protection Bureau of Waste Site Cleanup and Office of Research and Standards Boston MA WSCORS-95shy141 July
DEP 1993 Memorandum to Catherine Wanat Project Manager WEROfrom Meg Harvey ORS Re Review of Revised Risk Assessment to Evaluate Need for Short-Term Measures in the 10-Year
ProjJDEGEHOliSATU5raquo3002RESrcOMMHEAISSUEALTPAIUwpltl CHEMRlSK - A DIVISION OF McLARENHART
Floodplain of the Housatonic River Massachusetts Department of Environmental Protection Office of Research and Standards Boston MA August 5
EFA 1996a Exposure Factors Handbook Volume I of III General Factors - Review Draft US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-95002Ba August
EPA 1996b Proposed Guidelines for Carcinogen Risk Assessment US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-92003C April
EPA 1992Dermal Exposure Assessment Principles and Applications US Environmental Protection Agency Office of Research and Development Washington DC EPA6008-9101 IB January
Guy RH and J Hadgraft 1987 Principles of skin permeability relevant to chemical exposure PB89-130009 NIOSH Grant K01-OH-00017 National Technical Information Service US Department of Commerce Springfield VA
Hawley JK 1985 Assessment of health risk from exposure to contaminated soil Risk Analysis 5289-302
IRIS 1997 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
IRIS 1994 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
Kissel JC KY Richter and RA Fenske 1996 Field measurement of dermal soil loading attributable to various activities Implications for exposure assessment Risk Anal 16 (1) 115-125
Roy TA JJ Yang AI Krueger and CR Mackerer 1990 Percutaneous absorption of neat 2378-tetrachlorodibenzo-p-dioxin (TCDD) and TCDD sorbed on soils Toxicology 10( I )308
Sheppard SC 1995 Parameter values to model the soil ingestion pathway Environmental Monitoring and Assessment 3427-44
Tryphonas H S Hayward L OGrady JCK Loo DL Arnold F Bryce and ZZ Zawidzka 1989 Immunotoxicity studies of PCB (Aroclor 1254) in the adult rhesus (Macaco mulatto) monkey - Preliminary report Int J Immunoph 11 (2) 199-206
PrOLGEGEHOllSAT2m002VRESPCOMMHEAlSSllEALTPAR2wpltj laquo CHEMRlSK bullbull A DIVISION OF McLARENHART
Tiyphonas H MI Luster G Schiffinan LL Dawson M Hodgen D Germolec S Hayward F Bryce JCK Loo F Mandy and DL Arnold 199 la Effect ofchronic exposure of PCB (Aroclor 1254) on specific and nonspecific immune parameters in the rhesus (Macaca mulatto) monkey FundAppl Toxicol 16773-786
Tiyphonas H MI Luster KL White PH Naylor MR EKlos GR Burleson D Germolec M Hodgen S Hayward and DL Arnold 1991b Effects of PCB (Aroclorreg 1254) on non-specific immune parameters in rhesus (Macaca mulatto) monkeys Int Immunoph 13(6)639-648
Wester RC HI Maibach L Sedik and J Melendres 1993 Percutaneous absorption of PCBs from soil In vivo rhesus monkey in vitro human skin and biding to powdered human stratum corneum Journal of Toxicology and Environmental Health 39375-282
Piuj_GEGEHOLPSATU5raquo3 (raquo2RESPCOMMHEAJSSUEAJ_TPAR2 wpd CHEMRjISK1 bullbull A DIVISION OF MCLARENHART
ATTACHMENT B
SCHEDULE - HUMAN HEALTH FOR HOUSATONIC
Deliverable (vith explanatory notes) Due Date
1 Baekcalculated Risk-Based Concentrations (RBCs) for PCBs for Residential Scenario 30 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in soil for the residential scenario taking into account Attachment A ambient air and indoor dust exposures and the potential presence of a garden It will also present all exposure and toxicity parameter values used in deriving those RBCs In addition it will include an evaluation of exposures to PCBs from lawn mowing and a description of the methodology used in that evaluation
Backcaiculated RBCs for PCBs for Other Scenarios 60 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in the pertinent media for the scenarios described Attachment A beiow together with all exposure and toxicity parameter values used in deriving those RBCs
o General recreational o Canoeing Q Swimming o Dirt hiking o Current commercial use o Current agricultural use o Utility worker o Construction worker o Fish consumption (from recreational fishing)
- 2 shy
Deliverable (with explanatory notes) Lme uate
3 Proposal Addendum Regarding Useable Data Other COPCs and Other Biota January 30 1998
This subrnittal will present the results of andor proposals for several tasks in the risk assessment process
a Data evaluation This subrnittal will present the results of the data evaluation as described in Section 3 of the Risk Assessment Proposal and will include a summarization of useable data This evaluation will necessarily be based on available data and thus will not be able to take account of the results of any additional Phase IIRFI investigations that may be required by the Agencies The data evaluation is estimated to take approximately 2-3 months and must be completed before the selection of other (non-PCB) Chemicals of Potential Concern (COPCs) car- be conducted
b Proposal on other COPCs This subrnittal will also present a proposal regarding other (non-PCB) COPCs It will include
o Identification of other COPCs based on the data evaluation results and the selection criteria described in the Proposal (including comparison to upstream levels)
o Dose-response assessment and proposal of toxicity values for these COPCs o Proposal of RAFs and other chemical-specific exposure parameters for these COPCs o Identification of areas where these COPCs have been detected in concentrations exceeding
upstream levels and o Identification of pertinent exposure scenarios for those areas
These tasks will take approximately 2 months after completion of the data evaluation
c Proposal regarding consumption of other biota This submittal will further include a proposal for the evaluation of consumption of biota other than fish It will include a proposal as to the specific species to be evaluated the method of evaluation (quantitative or qualitative) and the parameter values to be used in the quantitative evaluations (Note This item may have to be postponed to a later date if GE has not received from the Agencies the results of the Univ of Mass fiddlehead fern study in the time for consideration prior to the due date for this subrnittal)
-3 shy
Deliverable (with explanatory notes)
4 Backcalculated RBCs for Other COPCs for Relevant Scenarios
This subrnittal will present the backcalculated RBCs for the other identified COPCs in the pertinent media for the exposure scenarios identified as relevant to the areas where such COPCs have been detected It will also present all exposure and toxieity parameter values used in deriving those COPCs
Backcaiculated RBCs for Consumption of Other Biota
This subrnitta will present the backcalculated RBCs for the consumption of biota other than fish These RBCs win be presented for those species for which quantitative evaluation was conducted (The qualitative evaluation of other species will be included in the final risk assessment report)
6 Interim Risk Assessment Report - Application of RBCs Based on Current Use
This subrnkta will provide an Interim report on the risk assessment It will include a brief summary of the approach used and the prior submittals including the exposure scenarios and RBCs for each scenario It will also present sample forward risk calculations for each scenario using a dummy Exposure Point Concentration (EPC) It will further present the results of the application of the RBCs for PCBs (and other COPCs where applicable) to the relevant exposure points under current use assumptions This will include
o Identification of current uses of the site (by area) and the applicable exposure scenario based on such use o Identification of exposure points for each scenario based on current use o Calculation of EPCs for each exposure point (for PCBs and other COPCs where measured)
including a justification for the method of calculating them o Comparison of EPCs to applicable RBCs for each exposure point o Conclusion for each exposure point regarding presence of significant risk for applicable scenario and o Brief discussion of uncertainties and risk perspective
30 days from Agencies approval of proposal or- other COPCs (hern 3b)
30 days from Agencies approval of proposal for evaluation of consumption of other biota (Item 3c)
75 days from Agencies approval of Item 1 2 4 or 5 whichever is latest
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
- 5 shy
Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
their results in 1995 These data allow the derivation of an RfD that is specifically based on reproductive and developmental effects of Aroclor 1254 in rhesus monkeys
CheniRisk has developed such an RfD for use in the evaluation of subchronic exposures to a young woman during the nine months of her pregnancy in the relevant scenarios of the human health risk assessment for the Housatonic River Consistent with EPAs methodology in deriving RfDs from this group of studies several uncertainty factors have been applied to the lowest adverse effects level (LOAEL) of 0005 mgkg-day reported by Arnold et al (1995) to derive this RfD An uncertainty factor of 3 was used to account for interspecies extrapolation This uncertainly factor is appropriate due to the similarities in toxic responses and metabolism of PCBs by monkeys and humans and the general physiologic similarities between the species Another uncertainty factor of 3 was applied to account for the use of a LOAEL instead of a no adverse effect level (NOAEL) value This factor is appropriate because the effects observed in the young monkeys were not frank effects and are not necessarily adverse Finally an additional uncertainty factor of 10 was applied to account for interindividual variation or sensitivity within the population Application of the above safety factors results in a total uncertainty factor of 90 (3 x 3 x 10 == 90) which when applied to the LOAEL of 0005 mgkg-day results in a reproductivedeveloprnental RfD of 55 x 10s rngkg-day or 55 ngkgshyday
An additional uncertainty factor was not applied for translation from subchronic to chronic exposure duration because as DEP (1995) guidance recognizes exposure during nine months of pregnancy is a subchronic exposure scenario Moreover the actual overall exposure period for the adult female monkeys in the Arnold et al (1995) study (as in the prior studies from this group) was longer than one year and most of the adult monkeys had reached a steady stale body burden of PCBs before the studies of reproductive and developmental effects were initiated Hence the use of a subchronic exposure duration that is equivalent to the period of pregnancy (ie nine months) constitutes additional conservatism in the approach for assessing the developmental effects of PCBs
This subchronic RfD of 55 ngkg-day is a conservative estimate of the RfD in that it uses a safety factor of 10 to adjust for interindividual variation or sensitivity In fact because the RfD is based on effects in infant monkeys an already highly sensitive population a safety factor of 3 to account for interindividual variation among members of that sensitive subpopulation would be sufficient for developing an RfD In addition the study results appear to indicate that the infants may not have been more sensitive than the mothers as the changes observed in the infant monkeys were of similar or lesser severity than the maternal monkeys If a safety factor of 3 were used instead of the factor of 10 the result would be a total uncertainly factor of approximately 30 (3 x 3 x 3 == 27) resulting in a higher but still protective developmental RfD of 200 ngkg-day
Given the uncertainties associated with the derivation of an RfD for developmental effects GE has elected to take the more conservative approach and propose a subchronic developmental RfD of 55 x 10 mgkg-day for use in the Housatonic River risk assessment This value will be used to
PruLGDGEHOUSAT2593002RESKraquoMMHEAISSUEALTPAIU wpd - CHEMRlSK - A DIVISION OF McLARENHART
evaluate potential reproductive and developmental effects of PCBs in pregnant women and their offspring as a result of exposure during nine months of pregnancy in all scenarios for which this subchronic exposure scenario is proposed
Enhanced Soil Ingestion Rate for Adult Fanners
In Comment 56 of the final comments on the Proposal for Human Health Risk Assessment for the Housatonic River the Agencies stated that GE should use the DEP and EPA default enhanced soil ingestion rate of 480 nigday to evaluate potential soil ingestion exposures for the adult farmer unless it can provide a credible and relevant justification for an alternative rate
The current default enhanced ingestion rate of 480 mgday is an estimated rate of soil ingestion developed by Hawley (1985) based on his review of the soil ingestion literature available at that time While the estimates provided by Hawley have been used extensively to simulate high-end exposures via the soil ingestion pathway Hawleys estimates are not based on empirical data Rather Hawley derived his estimates based on assumptions about soildust levels on hands mouthing behavior and frequencies of indoor and outdoor activities According to the evaluation of soil ingestion studies conducted by EPA in preparing its August 1996 draft of the Exposure Factors Handbook Hawleys estimates must be considered conjectural due to the lack of supporting measurements
To derive his estimate of soil ingestion Hawley assumed that an adult while engaged in yard work or other physical activity would ingest the amount of soil that could coal the inside surface of the fingers and thumbs He estimated that soil could adhere to the skin at a rate of 35 mgcnr This estimated adherence factor was not measured rather it was based on the density of soil particles and Hawleys approximation of the depth of the layer of soil (50 pm) that might adhere to exposed skin on such an individual According to Sheppard (1995) Hawleys assumption of a 50 urn thick layer of soil on the arms and hands represents a very high and conspicuous soil load Sheppard reported that loads less than 1 mgcnr2 are more reasonable for making this calculation due to the fact that soil loads on the skin greater than 1 mgcm2 would be so noticeable that they would deter mouthing behavior until hands were washed or cleaned off
Since Hawleys approach was developed and Sheppard provided his evaluation of Hawleys approach new data on soil adherence have been published As reported by EPA (1996a) Kissel et al (1996) directly measured the soil loading on skin surfaces as a result of various occupational and recreational activities This study indicates that soil loadings vary with the type of activity and the body parts contacted As one would expect adherence appears to be greatest during outdoor activities such as farming and gardening and moire soildust tends to adhere to the hands and knees than to other areas of the body As measured by Kissel et al (1996) soil loadings for farmers hands range between 020 and 084 mgcm2 while adherence rates for other pants of their bodies are lower Values for other types of occupational exposures including irrigation workers and groundskeepers
ProuGEGEHOUSAT2mltX)2RESPCOMMlaquoEAISSUEALTPAR2wpd - CHEMRlSK - A DIVISION OF MCLARENHART
were measured to be less than 05 nigcnr In every case soil adherence during occupational exposures was measured to be considerably lower than Hawleys estimate of 35 mgcnr
In Dermal Exposure Assessment Principles and Applications (EPA 1992) 1EPA recommends a soil adherence range of 02 to 1 mgcm2 For typical exposure to outdoor soil DEP (1995) recommends a soil adherence value of 051 mgcnr2 All of these values are consistent with the adherence rates measured by Kissel et al (1996) suggesting that soil loadings greater than 10 mgcnr during outdoor activities such as fanning are not realistic
In addition it is unlikely that hand-to-mouth contact would occur at Hawleys estimated loading rate It is instead likely that individuals who have a soil loading of this magnitude would not pick up food or put their hands in their mouths before washing or wiping their hands to remove the excess soil
According to Sheppard (1995) it may be reasonable to assume that mouthing behavior could occur at a loading rate of 10 mgcnr As this loading rale is at the upper end of the range of soil loading rates supported by both EPA and DEP and is higher than the highest soil loading rates reported by Kissel et al for the hands of farmers or any other adult exposure this soil loading rate has been used in combination with Hawleys other assumptions to derive an enhanced soil ingestion rate for farmers
If one substitutes the value of 10 mgcm2 for Hawleys assumption of 35 mgcm2 and continues to use Hawleys other exposure assumptions the resulting enhanced outdoor soil ingestion rate is 137 nigday For the purposes of the Housatonic River risk assessment GE proposes to use this more empirically-based enhanced adult soil ingestion rate of 137 ingday for the adult fanner
Derma] Absorption Rate for PCBs
In Comment 62 of their final comments on the Proposal for Human Health Risk Assessment for the Housatonic River the Agencies stated that they disagree with the use of dermal ilbsorption values of 146 percent and 143 percent proposed by GE for soils and sediment respectively The Agencies reconinnended instead that GE use a dermal absorption factor of 14 percent unless GE provides a credible and relevant justification for an alternative dermal absorption factor GE believes that a dermal absorption factor of 14 percent is not justifiable for the Housatonic River risk assessment due to limitations of the study upon which it is based and site-specific factors that indicate that such an estimate likely overstates actual absorption of PCBs from soils and sediments at this site
The dermal absorption values originally proposed by GE for soils and sediment were calculated by ChemRisk based on data from Roy et al (1990) As discussed in detail in the EPAs (1992) Dermal Exposure Assessment Guidance Principles and Applications Roy et al (1990) studied percutaneous absorption of tetrachlorobiphenyl (TCB) through human skin (in vitro) TCB was applied to human skin for 96 hours at a concentration of 1000 rngkg in soil with a low (045
Prni_GEGEHOUSAT2SW 002RESPCOMMHEAISSlEALTPA]U wpd 4 CHEMRlSK bullbullA DIVISION OF IVICL AH ENHART
percent) organic carbon content Absorption through human skin was 736 percent after 96 hours of exposure but negligible after only eight hours of exposure Roy et al (1990) also studied absorption from soil by rat skin in vitro and in vivo Total in vitro absorption from high (1122 percent) organic carbon content soil over 96 hours was 964 percent while absorption from low organic carbon soil in vitro in rats was 3195 percent over 96 hours For low organic carbon soil the absorption for the rat in vivo was 497 percent absorption after 96 hours
In its analysis EPA (1992) adjusted the Roy et al data to derive estimates of in vivo absorption of TCB in humans based on 24-hour exposure This was accomplished by adjusting the data to reflect differences between in vitro and in vivo tests rat and human skin and organic carbon content of the soil The adjusted percent TCB absorbed from soil was estimated to range from 063 percent for soil with high organic carbon content to 21 percent for soil with low organic carbon content Considering the uncertainty in these estimates EPA (1992) recommended a range of 06 percent to 6 percent for the percent of TCB dermally absorbed from the soil Moreover by comparing the Roy et al (1990) data to in vivo data from other bioavailability studies using other PCBs EPA (1992) concluded that the uptake of TCB was similar to that of other PCBs and that the range of 06 percent to 6 percent absorption for TCB is generally appropriate for PCBs
As these data indicate the dermal absorption of PCBs in soil is highly dependent on the organic carbon content of the soil GE proposed to account for this dependency by extrapolating from the Roy et al data to the relatively high site-specific organic carbon content of soils and sediments at the site DEP (1993) had previously agreed that it was appropriate to derive dermal absorption factors based on site-specific organic carbon content data as long as the organic carbon values used were based on reliable dala Because there are substantial data on the organic carbon contents of site soils and sediments GE proposed to use site-specific dermal absorption factors based on extrapolations of the Roy et al (1990) findings
In Comment 62 the Agencies stated that they no longer support the site-specific dermal absorption values previously derived by GE due to the findings of a study by Wester et al (1993) which indicated that dermal absorption of PCBs may be higher than that estimated by EPA using the Roy et al (1990) data The Wester et al (1993) study was designed to measure the extent to which Aroclors 1242 and 1254 would partition out of soil and be absorbed through the skin Wester et al (1993) added radio-labeled Aroclor 1242 and Aroclor 1234 to soil containing 26 percent sand 26 percent clay 48 percent silt and 09 percent organic carbon content Soils were mixed by hand to final concentrations of 44 mgkg Aroclor 1242 and 23 mgkg Aroclor 1254 These soils were then applied to the clipped abdominal skin of adult female rhesus monkeys for a period of 24 hours in a manner that would prevent the animals from licking or scratching at the skirt and would prevent exfoliated skin from contaminating urine or feces The skin site was covered with a non-occlusive cover that permitted air and moisture to move freely to and from the skin but retained the soil at the application site Urine and feces were collected during the exposure period After 24 hours skin
Proi_GEGEHOVSArumW2MSPCOMMVHEAISSUEALTPARiwpltl bull CHEMRlSK - A DIVISION OF MCLARENHART
was washed and urine and feces were periodically measured and analyzed for PCBs for 34 days following exposure
Percutaneous absorption was determined by urinary and fecal excretion following topical and intravenous administration Based on their measured recoveries combined with excretion efficiency data previously measured at their laboratory Wester et al (1993) concluded that the percutaneous absorptions of Aroclor 1242 and Aroclor 1254 from soil were 138 plusmn 27 percent and 141 + 10 percent of dose respectively Recovery of PCBs from skin was 83 percent for Aroclor 1242 and 72 percent for Aroclor 1254 most of the recovered dose was in the residual soil indicating that the PCBs had remained bound to soil during that 24-hour period rather than adsorbing to skin
While the Wester et al (1993) study was a well-conducted study that used appropriate experimental methodology there are several aspects of the study that limit its usefulness as a basis for developing dermal absorption factors for this site-specific risk assessment First Wester et al (1993) evaluated soils that had an organic carbon content of 09 percent and they did not test for variations in dermal absorption from soils with higher organic carbon contents This organic carbon content is very low and is not consistent with the levels of organic carbon content found in soils and sediments of the Housatonic River and its floodplain (ranging from 01 - 26 percent with arithmetic means of 50 and 53 percent for soils and sediments respectively) It is likely based on the clear trends shown in the Roy et al (1990) data that if higher levels of organic carbon had been tested by Wester et al (1993) the result would have been lower levels of percutaneous absorption
Second Wester et al (1993) applied soil to the animals skin at a rate of 40 ing soilcm2 skin (resulting in PCB concentrations on the skin of 175 ug PCBcm for Aroclor 1242 and 091 pg PCBcm2 for Aroclor 1254) This application rate is substantially greater than the adherence rates measured by Kissel et al (1996) or considered appropriate by DEP or EPA This higher rate of application may have increased the absorption of PCBs through the skin
Third the study used freshly spiked commercial PCB mixtures As discussed by EPA (1996b) in its reassessment of the carcinogenic potential of environmental PCB mixtures the composition of PCB mixtures changes over time through differential partitioning and chemical transformation of the component congeners For example congeners of lower chlorine content tend to be more volatile and also more soluble in water with rates of vaporization and relative water solubilities varying over several orders of magnitude between congeners These processes of volatilization and dissolution would appear to reduce the relative dermal absorption of a weathered PCB mixture compared to that of a freshly spiked sample In addition a weathered PCB mixture should form a tighter affinity to an environmental soil matrix over time further reducing its availability to become dermally absorbed
Finally Guy and Hadgraft (1987) reported that the permeability of skin in various parts of the body may be highly variable They reported that studies of hydrocortisone malathion and parathion have
ProjJ3DGEHOUSATU5laquoU02RESKOMMHEAISSUEALTPARlwpd - CHEMRlSK - A DIVISION OF McLARENHART
indicated that absorption across leg and forearm skin is similar but that the skin of the trunk is 25 times more permeable than the skin of the forearm or leg If this is also the case for PCBs it may be reasonable to conclude that absorption through the abdominal skin of the Wester at al (1993) monkeys may overestimate absorption through the skin of the arms or legs by as much as a factor of 25 If this were shown to be the case the result would be a dermal absorption of approximately 6 percent similar to the absorption factor recommended by EPA (1992) based on the Roy et al (1990) study for low carbon content soils over 24 hours of exposure
While the Wester et al (1993) study was a well conducted study the above-outlined limitations and uncertainties undermine its usefulness for this site-specific risk assessment In addition EPA has convened a dermal workgroup to evaluate the dermal absorption of PCBs and make recommendations for a revised absorption factor if appropriate This work group has not yet made a final recommendation When the work group has finished its analysis and EPA makes a recommendation on this issue GE will review that recommendation and all available data on dermal absorption of PCBs If however such a recommendation has not been made by the time that the risk assessment is conducted GE proposes to use the upper bound of current Agency guidance 6 percent for the evaluation of dermal absorption of PCBs from soil and sediment
References
Arnold DL F Bryce R Stapley PP McGuire D Burns JR Tanner and K Karpinski 1993a lexicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part 1A Prebreeding phase - clinical health findings Fd Chem Toxicol 31799-810
Arnold DL F Bryce K Karpinski J Mes S Fernie H Tryphonas J Truelove PP McGuire D Burns JR Tanner R Stapley ZZ Zawidzka and D Basford 1993b Toxicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part IB Prebreeding phase - clinical and analytical laboratory findings Fd Chem Toxicol 31811-824
Arnold D L F Bryce PP McGuire R Stapley JR Tanner E Wrenshall J Mes S Fernie H Tryphonas S Hayward and S Malcolm 1995 Toxicological consequences of Aroclor 1254 ingestion by female rhesus (Macaco mulatto) monkeys Part 2 Reproduction and infant findings Fd Chem Toxicol 33(6)457-474
DEP 1995 Guidance for Disposal Site Risk Characterization - In Support of the Massachusetts Contingency Plan - Interim Final Policy Massachusetts Department of Environmental Protection Bureau of Waste Site Cleanup and Office of Research and Standards Boston MA WSCORS-95shy141 July
DEP 1993 Memorandum to Catherine Wanat Project Manager WEROfrom Meg Harvey ORS Re Review of Revised Risk Assessment to Evaluate Need for Short-Term Measures in the 10-Year
ProjJDEGEHOliSATU5raquo3002RESrcOMMHEAISSUEALTPAIUwpltl CHEMRlSK - A DIVISION OF McLARENHART
Floodplain of the Housatonic River Massachusetts Department of Environmental Protection Office of Research and Standards Boston MA August 5
EFA 1996a Exposure Factors Handbook Volume I of III General Factors - Review Draft US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-95002Ba August
EPA 1996b Proposed Guidelines for Carcinogen Risk Assessment US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-92003C April
EPA 1992Dermal Exposure Assessment Principles and Applications US Environmental Protection Agency Office of Research and Development Washington DC EPA6008-9101 IB January
Guy RH and J Hadgraft 1987 Principles of skin permeability relevant to chemical exposure PB89-130009 NIOSH Grant K01-OH-00017 National Technical Information Service US Department of Commerce Springfield VA
Hawley JK 1985 Assessment of health risk from exposure to contaminated soil Risk Analysis 5289-302
IRIS 1997 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
IRIS 1994 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
Kissel JC KY Richter and RA Fenske 1996 Field measurement of dermal soil loading attributable to various activities Implications for exposure assessment Risk Anal 16 (1) 115-125
Roy TA JJ Yang AI Krueger and CR Mackerer 1990 Percutaneous absorption of neat 2378-tetrachlorodibenzo-p-dioxin (TCDD) and TCDD sorbed on soils Toxicology 10( I )308
Sheppard SC 1995 Parameter values to model the soil ingestion pathway Environmental Monitoring and Assessment 3427-44
Tryphonas H S Hayward L OGrady JCK Loo DL Arnold F Bryce and ZZ Zawidzka 1989 Immunotoxicity studies of PCB (Aroclor 1254) in the adult rhesus (Macaco mulatto) monkey - Preliminary report Int J Immunoph 11 (2) 199-206
PrOLGEGEHOllSAT2m002VRESPCOMMHEAlSSllEALTPAR2wpltj laquo CHEMRlSK bullbull A DIVISION OF McLARENHART
Tiyphonas H MI Luster G Schiffinan LL Dawson M Hodgen D Germolec S Hayward F Bryce JCK Loo F Mandy and DL Arnold 199 la Effect ofchronic exposure of PCB (Aroclor 1254) on specific and nonspecific immune parameters in the rhesus (Macaca mulatto) monkey FundAppl Toxicol 16773-786
Tiyphonas H MI Luster KL White PH Naylor MR EKlos GR Burleson D Germolec M Hodgen S Hayward and DL Arnold 1991b Effects of PCB (Aroclorreg 1254) on non-specific immune parameters in rhesus (Macaca mulatto) monkeys Int Immunoph 13(6)639-648
Wester RC HI Maibach L Sedik and J Melendres 1993 Percutaneous absorption of PCBs from soil In vivo rhesus monkey in vitro human skin and biding to powdered human stratum corneum Journal of Toxicology and Environmental Health 39375-282
Piuj_GEGEHOLPSATU5raquo3 (raquo2RESPCOMMHEAJSSUEAJ_TPAR2 wpd CHEMRjISK1 bullbull A DIVISION OF MCLARENHART
ATTACHMENT B
SCHEDULE - HUMAN HEALTH FOR HOUSATONIC
Deliverable (vith explanatory notes) Due Date
1 Baekcalculated Risk-Based Concentrations (RBCs) for PCBs for Residential Scenario 30 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in soil for the residential scenario taking into account Attachment A ambient air and indoor dust exposures and the potential presence of a garden It will also present all exposure and toxicity parameter values used in deriving those RBCs In addition it will include an evaluation of exposures to PCBs from lawn mowing and a description of the methodology used in that evaluation
Backcaiculated RBCs for PCBs for Other Scenarios 60 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in the pertinent media for the scenarios described Attachment A beiow together with all exposure and toxicity parameter values used in deriving those RBCs
o General recreational o Canoeing Q Swimming o Dirt hiking o Current commercial use o Current agricultural use o Utility worker o Construction worker o Fish consumption (from recreational fishing)
- 2 shy
Deliverable (with explanatory notes) Lme uate
3 Proposal Addendum Regarding Useable Data Other COPCs and Other Biota January 30 1998
This subrnittal will present the results of andor proposals for several tasks in the risk assessment process
a Data evaluation This subrnittal will present the results of the data evaluation as described in Section 3 of the Risk Assessment Proposal and will include a summarization of useable data This evaluation will necessarily be based on available data and thus will not be able to take account of the results of any additional Phase IIRFI investigations that may be required by the Agencies The data evaluation is estimated to take approximately 2-3 months and must be completed before the selection of other (non-PCB) Chemicals of Potential Concern (COPCs) car- be conducted
b Proposal on other COPCs This subrnittal will also present a proposal regarding other (non-PCB) COPCs It will include
o Identification of other COPCs based on the data evaluation results and the selection criteria described in the Proposal (including comparison to upstream levels)
o Dose-response assessment and proposal of toxicity values for these COPCs o Proposal of RAFs and other chemical-specific exposure parameters for these COPCs o Identification of areas where these COPCs have been detected in concentrations exceeding
upstream levels and o Identification of pertinent exposure scenarios for those areas
These tasks will take approximately 2 months after completion of the data evaluation
c Proposal regarding consumption of other biota This submittal will further include a proposal for the evaluation of consumption of biota other than fish It will include a proposal as to the specific species to be evaluated the method of evaluation (quantitative or qualitative) and the parameter values to be used in the quantitative evaluations (Note This item may have to be postponed to a later date if GE has not received from the Agencies the results of the Univ of Mass fiddlehead fern study in the time for consideration prior to the due date for this subrnittal)
-3 shy
Deliverable (with explanatory notes)
4 Backcalculated RBCs for Other COPCs for Relevant Scenarios
This subrnittal will present the backcalculated RBCs for the other identified COPCs in the pertinent media for the exposure scenarios identified as relevant to the areas where such COPCs have been detected It will also present all exposure and toxieity parameter values used in deriving those COPCs
Backcaiculated RBCs for Consumption of Other Biota
This subrnitta will present the backcalculated RBCs for the consumption of biota other than fish These RBCs win be presented for those species for which quantitative evaluation was conducted (The qualitative evaluation of other species will be included in the final risk assessment report)
6 Interim Risk Assessment Report - Application of RBCs Based on Current Use
This subrnkta will provide an Interim report on the risk assessment It will include a brief summary of the approach used and the prior submittals including the exposure scenarios and RBCs for each scenario It will also present sample forward risk calculations for each scenario using a dummy Exposure Point Concentration (EPC) It will further present the results of the application of the RBCs for PCBs (and other COPCs where applicable) to the relevant exposure points under current use assumptions This will include
o Identification of current uses of the site (by area) and the applicable exposure scenario based on such use o Identification of exposure points for each scenario based on current use o Calculation of EPCs for each exposure point (for PCBs and other COPCs where measured)
including a justification for the method of calculating them o Comparison of EPCs to applicable RBCs for each exposure point o Conclusion for each exposure point regarding presence of significant risk for applicable scenario and o Brief discussion of uncertainties and risk perspective
30 days from Agencies approval of proposal or- other COPCs (hern 3b)
30 days from Agencies approval of proposal for evaluation of consumption of other biota (Item 3c)
75 days from Agencies approval of Item 1 2 4 or 5 whichever is latest
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
- 5 shy
Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
evaluate potential reproductive and developmental effects of PCBs in pregnant women and their offspring as a result of exposure during nine months of pregnancy in all scenarios for which this subchronic exposure scenario is proposed
Enhanced Soil Ingestion Rate for Adult Fanners
In Comment 56 of the final comments on the Proposal for Human Health Risk Assessment for the Housatonic River the Agencies stated that GE should use the DEP and EPA default enhanced soil ingestion rate of 480 nigday to evaluate potential soil ingestion exposures for the adult farmer unless it can provide a credible and relevant justification for an alternative rate
The current default enhanced ingestion rate of 480 mgday is an estimated rate of soil ingestion developed by Hawley (1985) based on his review of the soil ingestion literature available at that time While the estimates provided by Hawley have been used extensively to simulate high-end exposures via the soil ingestion pathway Hawleys estimates are not based on empirical data Rather Hawley derived his estimates based on assumptions about soildust levels on hands mouthing behavior and frequencies of indoor and outdoor activities According to the evaluation of soil ingestion studies conducted by EPA in preparing its August 1996 draft of the Exposure Factors Handbook Hawleys estimates must be considered conjectural due to the lack of supporting measurements
To derive his estimate of soil ingestion Hawley assumed that an adult while engaged in yard work or other physical activity would ingest the amount of soil that could coal the inside surface of the fingers and thumbs He estimated that soil could adhere to the skin at a rate of 35 mgcnr This estimated adherence factor was not measured rather it was based on the density of soil particles and Hawleys approximation of the depth of the layer of soil (50 pm) that might adhere to exposed skin on such an individual According to Sheppard (1995) Hawleys assumption of a 50 urn thick layer of soil on the arms and hands represents a very high and conspicuous soil load Sheppard reported that loads less than 1 mgcnr2 are more reasonable for making this calculation due to the fact that soil loads on the skin greater than 1 mgcm2 would be so noticeable that they would deter mouthing behavior until hands were washed or cleaned off
Since Hawleys approach was developed and Sheppard provided his evaluation of Hawleys approach new data on soil adherence have been published As reported by EPA (1996a) Kissel et al (1996) directly measured the soil loading on skin surfaces as a result of various occupational and recreational activities This study indicates that soil loadings vary with the type of activity and the body parts contacted As one would expect adherence appears to be greatest during outdoor activities such as farming and gardening and moire soildust tends to adhere to the hands and knees than to other areas of the body As measured by Kissel et al (1996) soil loadings for farmers hands range between 020 and 084 mgcm2 while adherence rates for other pants of their bodies are lower Values for other types of occupational exposures including irrigation workers and groundskeepers
ProuGEGEHOUSAT2mltX)2RESPCOMMlaquoEAISSUEALTPAR2wpd - CHEMRlSK - A DIVISION OF MCLARENHART
were measured to be less than 05 nigcnr In every case soil adherence during occupational exposures was measured to be considerably lower than Hawleys estimate of 35 mgcnr
In Dermal Exposure Assessment Principles and Applications (EPA 1992) 1EPA recommends a soil adherence range of 02 to 1 mgcm2 For typical exposure to outdoor soil DEP (1995) recommends a soil adherence value of 051 mgcnr2 All of these values are consistent with the adherence rates measured by Kissel et al (1996) suggesting that soil loadings greater than 10 mgcnr during outdoor activities such as fanning are not realistic
In addition it is unlikely that hand-to-mouth contact would occur at Hawleys estimated loading rate It is instead likely that individuals who have a soil loading of this magnitude would not pick up food or put their hands in their mouths before washing or wiping their hands to remove the excess soil
According to Sheppard (1995) it may be reasonable to assume that mouthing behavior could occur at a loading rate of 10 mgcnr As this loading rale is at the upper end of the range of soil loading rates supported by both EPA and DEP and is higher than the highest soil loading rates reported by Kissel et al for the hands of farmers or any other adult exposure this soil loading rate has been used in combination with Hawleys other assumptions to derive an enhanced soil ingestion rate for farmers
If one substitutes the value of 10 mgcm2 for Hawleys assumption of 35 mgcm2 and continues to use Hawleys other exposure assumptions the resulting enhanced outdoor soil ingestion rate is 137 nigday For the purposes of the Housatonic River risk assessment GE proposes to use this more empirically-based enhanced adult soil ingestion rate of 137 ingday for the adult fanner
Derma] Absorption Rate for PCBs
In Comment 62 of their final comments on the Proposal for Human Health Risk Assessment for the Housatonic River the Agencies stated that they disagree with the use of dermal ilbsorption values of 146 percent and 143 percent proposed by GE for soils and sediment respectively The Agencies reconinnended instead that GE use a dermal absorption factor of 14 percent unless GE provides a credible and relevant justification for an alternative dermal absorption factor GE believes that a dermal absorption factor of 14 percent is not justifiable for the Housatonic River risk assessment due to limitations of the study upon which it is based and site-specific factors that indicate that such an estimate likely overstates actual absorption of PCBs from soils and sediments at this site
The dermal absorption values originally proposed by GE for soils and sediment were calculated by ChemRisk based on data from Roy et al (1990) As discussed in detail in the EPAs (1992) Dermal Exposure Assessment Guidance Principles and Applications Roy et al (1990) studied percutaneous absorption of tetrachlorobiphenyl (TCB) through human skin (in vitro) TCB was applied to human skin for 96 hours at a concentration of 1000 rngkg in soil with a low (045
Prni_GEGEHOUSAT2SW 002RESPCOMMHEAISSlEALTPA]U wpd 4 CHEMRlSK bullbullA DIVISION OF IVICL AH ENHART
percent) organic carbon content Absorption through human skin was 736 percent after 96 hours of exposure but negligible after only eight hours of exposure Roy et al (1990) also studied absorption from soil by rat skin in vitro and in vivo Total in vitro absorption from high (1122 percent) organic carbon content soil over 96 hours was 964 percent while absorption from low organic carbon soil in vitro in rats was 3195 percent over 96 hours For low organic carbon soil the absorption for the rat in vivo was 497 percent absorption after 96 hours
In its analysis EPA (1992) adjusted the Roy et al data to derive estimates of in vivo absorption of TCB in humans based on 24-hour exposure This was accomplished by adjusting the data to reflect differences between in vitro and in vivo tests rat and human skin and organic carbon content of the soil The adjusted percent TCB absorbed from soil was estimated to range from 063 percent for soil with high organic carbon content to 21 percent for soil with low organic carbon content Considering the uncertainty in these estimates EPA (1992) recommended a range of 06 percent to 6 percent for the percent of TCB dermally absorbed from the soil Moreover by comparing the Roy et al (1990) data to in vivo data from other bioavailability studies using other PCBs EPA (1992) concluded that the uptake of TCB was similar to that of other PCBs and that the range of 06 percent to 6 percent absorption for TCB is generally appropriate for PCBs
As these data indicate the dermal absorption of PCBs in soil is highly dependent on the organic carbon content of the soil GE proposed to account for this dependency by extrapolating from the Roy et al data to the relatively high site-specific organic carbon content of soils and sediments at the site DEP (1993) had previously agreed that it was appropriate to derive dermal absorption factors based on site-specific organic carbon content data as long as the organic carbon values used were based on reliable dala Because there are substantial data on the organic carbon contents of site soils and sediments GE proposed to use site-specific dermal absorption factors based on extrapolations of the Roy et al (1990) findings
In Comment 62 the Agencies stated that they no longer support the site-specific dermal absorption values previously derived by GE due to the findings of a study by Wester et al (1993) which indicated that dermal absorption of PCBs may be higher than that estimated by EPA using the Roy et al (1990) data The Wester et al (1993) study was designed to measure the extent to which Aroclors 1242 and 1254 would partition out of soil and be absorbed through the skin Wester et al (1993) added radio-labeled Aroclor 1242 and Aroclor 1234 to soil containing 26 percent sand 26 percent clay 48 percent silt and 09 percent organic carbon content Soils were mixed by hand to final concentrations of 44 mgkg Aroclor 1242 and 23 mgkg Aroclor 1254 These soils were then applied to the clipped abdominal skin of adult female rhesus monkeys for a period of 24 hours in a manner that would prevent the animals from licking or scratching at the skirt and would prevent exfoliated skin from contaminating urine or feces The skin site was covered with a non-occlusive cover that permitted air and moisture to move freely to and from the skin but retained the soil at the application site Urine and feces were collected during the exposure period After 24 hours skin
Proi_GEGEHOVSArumW2MSPCOMMVHEAISSUEALTPARiwpltl bull CHEMRlSK - A DIVISION OF MCLARENHART
was washed and urine and feces were periodically measured and analyzed for PCBs for 34 days following exposure
Percutaneous absorption was determined by urinary and fecal excretion following topical and intravenous administration Based on their measured recoveries combined with excretion efficiency data previously measured at their laboratory Wester et al (1993) concluded that the percutaneous absorptions of Aroclor 1242 and Aroclor 1254 from soil were 138 plusmn 27 percent and 141 + 10 percent of dose respectively Recovery of PCBs from skin was 83 percent for Aroclor 1242 and 72 percent for Aroclor 1254 most of the recovered dose was in the residual soil indicating that the PCBs had remained bound to soil during that 24-hour period rather than adsorbing to skin
While the Wester et al (1993) study was a well-conducted study that used appropriate experimental methodology there are several aspects of the study that limit its usefulness as a basis for developing dermal absorption factors for this site-specific risk assessment First Wester et al (1993) evaluated soils that had an organic carbon content of 09 percent and they did not test for variations in dermal absorption from soils with higher organic carbon contents This organic carbon content is very low and is not consistent with the levels of organic carbon content found in soils and sediments of the Housatonic River and its floodplain (ranging from 01 - 26 percent with arithmetic means of 50 and 53 percent for soils and sediments respectively) It is likely based on the clear trends shown in the Roy et al (1990) data that if higher levels of organic carbon had been tested by Wester et al (1993) the result would have been lower levels of percutaneous absorption
Second Wester et al (1993) applied soil to the animals skin at a rate of 40 ing soilcm2 skin (resulting in PCB concentrations on the skin of 175 ug PCBcm for Aroclor 1242 and 091 pg PCBcm2 for Aroclor 1254) This application rate is substantially greater than the adherence rates measured by Kissel et al (1996) or considered appropriate by DEP or EPA This higher rate of application may have increased the absorption of PCBs through the skin
Third the study used freshly spiked commercial PCB mixtures As discussed by EPA (1996b) in its reassessment of the carcinogenic potential of environmental PCB mixtures the composition of PCB mixtures changes over time through differential partitioning and chemical transformation of the component congeners For example congeners of lower chlorine content tend to be more volatile and also more soluble in water with rates of vaporization and relative water solubilities varying over several orders of magnitude between congeners These processes of volatilization and dissolution would appear to reduce the relative dermal absorption of a weathered PCB mixture compared to that of a freshly spiked sample In addition a weathered PCB mixture should form a tighter affinity to an environmental soil matrix over time further reducing its availability to become dermally absorbed
Finally Guy and Hadgraft (1987) reported that the permeability of skin in various parts of the body may be highly variable They reported that studies of hydrocortisone malathion and parathion have
ProjJ3DGEHOUSATU5laquoU02RESKOMMHEAISSUEALTPARlwpd - CHEMRlSK - A DIVISION OF McLARENHART
indicated that absorption across leg and forearm skin is similar but that the skin of the trunk is 25 times more permeable than the skin of the forearm or leg If this is also the case for PCBs it may be reasonable to conclude that absorption through the abdominal skin of the Wester at al (1993) monkeys may overestimate absorption through the skin of the arms or legs by as much as a factor of 25 If this were shown to be the case the result would be a dermal absorption of approximately 6 percent similar to the absorption factor recommended by EPA (1992) based on the Roy et al (1990) study for low carbon content soils over 24 hours of exposure
While the Wester et al (1993) study was a well conducted study the above-outlined limitations and uncertainties undermine its usefulness for this site-specific risk assessment In addition EPA has convened a dermal workgroup to evaluate the dermal absorption of PCBs and make recommendations for a revised absorption factor if appropriate This work group has not yet made a final recommendation When the work group has finished its analysis and EPA makes a recommendation on this issue GE will review that recommendation and all available data on dermal absorption of PCBs If however such a recommendation has not been made by the time that the risk assessment is conducted GE proposes to use the upper bound of current Agency guidance 6 percent for the evaluation of dermal absorption of PCBs from soil and sediment
References
Arnold DL F Bryce R Stapley PP McGuire D Burns JR Tanner and K Karpinski 1993a lexicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part 1A Prebreeding phase - clinical health findings Fd Chem Toxicol 31799-810
Arnold DL F Bryce K Karpinski J Mes S Fernie H Tryphonas J Truelove PP McGuire D Burns JR Tanner R Stapley ZZ Zawidzka and D Basford 1993b Toxicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part IB Prebreeding phase - clinical and analytical laboratory findings Fd Chem Toxicol 31811-824
Arnold D L F Bryce PP McGuire R Stapley JR Tanner E Wrenshall J Mes S Fernie H Tryphonas S Hayward and S Malcolm 1995 Toxicological consequences of Aroclor 1254 ingestion by female rhesus (Macaco mulatto) monkeys Part 2 Reproduction and infant findings Fd Chem Toxicol 33(6)457-474
DEP 1995 Guidance for Disposal Site Risk Characterization - In Support of the Massachusetts Contingency Plan - Interim Final Policy Massachusetts Department of Environmental Protection Bureau of Waste Site Cleanup and Office of Research and Standards Boston MA WSCORS-95shy141 July
DEP 1993 Memorandum to Catherine Wanat Project Manager WEROfrom Meg Harvey ORS Re Review of Revised Risk Assessment to Evaluate Need for Short-Term Measures in the 10-Year
ProjJDEGEHOliSATU5raquo3002RESrcOMMHEAISSUEALTPAIUwpltl CHEMRlSK - A DIVISION OF McLARENHART
Floodplain of the Housatonic River Massachusetts Department of Environmental Protection Office of Research and Standards Boston MA August 5
EFA 1996a Exposure Factors Handbook Volume I of III General Factors - Review Draft US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-95002Ba August
EPA 1996b Proposed Guidelines for Carcinogen Risk Assessment US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-92003C April
EPA 1992Dermal Exposure Assessment Principles and Applications US Environmental Protection Agency Office of Research and Development Washington DC EPA6008-9101 IB January
Guy RH and J Hadgraft 1987 Principles of skin permeability relevant to chemical exposure PB89-130009 NIOSH Grant K01-OH-00017 National Technical Information Service US Department of Commerce Springfield VA
Hawley JK 1985 Assessment of health risk from exposure to contaminated soil Risk Analysis 5289-302
IRIS 1997 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
IRIS 1994 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
Kissel JC KY Richter and RA Fenske 1996 Field measurement of dermal soil loading attributable to various activities Implications for exposure assessment Risk Anal 16 (1) 115-125
Roy TA JJ Yang AI Krueger and CR Mackerer 1990 Percutaneous absorption of neat 2378-tetrachlorodibenzo-p-dioxin (TCDD) and TCDD sorbed on soils Toxicology 10( I )308
Sheppard SC 1995 Parameter values to model the soil ingestion pathway Environmental Monitoring and Assessment 3427-44
Tryphonas H S Hayward L OGrady JCK Loo DL Arnold F Bryce and ZZ Zawidzka 1989 Immunotoxicity studies of PCB (Aroclor 1254) in the adult rhesus (Macaco mulatto) monkey - Preliminary report Int J Immunoph 11 (2) 199-206
PrOLGEGEHOllSAT2m002VRESPCOMMHEAlSSllEALTPAR2wpltj laquo CHEMRlSK bullbull A DIVISION OF McLARENHART
Tiyphonas H MI Luster G Schiffinan LL Dawson M Hodgen D Germolec S Hayward F Bryce JCK Loo F Mandy and DL Arnold 199 la Effect ofchronic exposure of PCB (Aroclor 1254) on specific and nonspecific immune parameters in the rhesus (Macaca mulatto) monkey FundAppl Toxicol 16773-786
Tiyphonas H MI Luster KL White PH Naylor MR EKlos GR Burleson D Germolec M Hodgen S Hayward and DL Arnold 1991b Effects of PCB (Aroclorreg 1254) on non-specific immune parameters in rhesus (Macaca mulatto) monkeys Int Immunoph 13(6)639-648
Wester RC HI Maibach L Sedik and J Melendres 1993 Percutaneous absorption of PCBs from soil In vivo rhesus monkey in vitro human skin and biding to powdered human stratum corneum Journal of Toxicology and Environmental Health 39375-282
Piuj_GEGEHOLPSATU5raquo3 (raquo2RESPCOMMHEAJSSUEAJ_TPAR2 wpd CHEMRjISK1 bullbull A DIVISION OF MCLARENHART
ATTACHMENT B
SCHEDULE - HUMAN HEALTH FOR HOUSATONIC
Deliverable (vith explanatory notes) Due Date
1 Baekcalculated Risk-Based Concentrations (RBCs) for PCBs for Residential Scenario 30 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in soil for the residential scenario taking into account Attachment A ambient air and indoor dust exposures and the potential presence of a garden It will also present all exposure and toxicity parameter values used in deriving those RBCs In addition it will include an evaluation of exposures to PCBs from lawn mowing and a description of the methodology used in that evaluation
Backcaiculated RBCs for PCBs for Other Scenarios 60 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in the pertinent media for the scenarios described Attachment A beiow together with all exposure and toxicity parameter values used in deriving those RBCs
o General recreational o Canoeing Q Swimming o Dirt hiking o Current commercial use o Current agricultural use o Utility worker o Construction worker o Fish consumption (from recreational fishing)
- 2 shy
Deliverable (with explanatory notes) Lme uate
3 Proposal Addendum Regarding Useable Data Other COPCs and Other Biota January 30 1998
This subrnittal will present the results of andor proposals for several tasks in the risk assessment process
a Data evaluation This subrnittal will present the results of the data evaluation as described in Section 3 of the Risk Assessment Proposal and will include a summarization of useable data This evaluation will necessarily be based on available data and thus will not be able to take account of the results of any additional Phase IIRFI investigations that may be required by the Agencies The data evaluation is estimated to take approximately 2-3 months and must be completed before the selection of other (non-PCB) Chemicals of Potential Concern (COPCs) car- be conducted
b Proposal on other COPCs This subrnittal will also present a proposal regarding other (non-PCB) COPCs It will include
o Identification of other COPCs based on the data evaluation results and the selection criteria described in the Proposal (including comparison to upstream levels)
o Dose-response assessment and proposal of toxicity values for these COPCs o Proposal of RAFs and other chemical-specific exposure parameters for these COPCs o Identification of areas where these COPCs have been detected in concentrations exceeding
upstream levels and o Identification of pertinent exposure scenarios for those areas
These tasks will take approximately 2 months after completion of the data evaluation
c Proposal regarding consumption of other biota This submittal will further include a proposal for the evaluation of consumption of biota other than fish It will include a proposal as to the specific species to be evaluated the method of evaluation (quantitative or qualitative) and the parameter values to be used in the quantitative evaluations (Note This item may have to be postponed to a later date if GE has not received from the Agencies the results of the Univ of Mass fiddlehead fern study in the time for consideration prior to the due date for this subrnittal)
-3 shy
Deliverable (with explanatory notes)
4 Backcalculated RBCs for Other COPCs for Relevant Scenarios
This subrnittal will present the backcalculated RBCs for the other identified COPCs in the pertinent media for the exposure scenarios identified as relevant to the areas where such COPCs have been detected It will also present all exposure and toxieity parameter values used in deriving those COPCs
Backcaiculated RBCs for Consumption of Other Biota
This subrnitta will present the backcalculated RBCs for the consumption of biota other than fish These RBCs win be presented for those species for which quantitative evaluation was conducted (The qualitative evaluation of other species will be included in the final risk assessment report)
6 Interim Risk Assessment Report - Application of RBCs Based on Current Use
This subrnkta will provide an Interim report on the risk assessment It will include a brief summary of the approach used and the prior submittals including the exposure scenarios and RBCs for each scenario It will also present sample forward risk calculations for each scenario using a dummy Exposure Point Concentration (EPC) It will further present the results of the application of the RBCs for PCBs (and other COPCs where applicable) to the relevant exposure points under current use assumptions This will include
o Identification of current uses of the site (by area) and the applicable exposure scenario based on such use o Identification of exposure points for each scenario based on current use o Calculation of EPCs for each exposure point (for PCBs and other COPCs where measured)
including a justification for the method of calculating them o Comparison of EPCs to applicable RBCs for each exposure point o Conclusion for each exposure point regarding presence of significant risk for applicable scenario and o Brief discussion of uncertainties and risk perspective
30 days from Agencies approval of proposal or- other COPCs (hern 3b)
30 days from Agencies approval of proposal for evaluation of consumption of other biota (Item 3c)
75 days from Agencies approval of Item 1 2 4 or 5 whichever is latest
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
- 5 shy
Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
were measured to be less than 05 nigcnr In every case soil adherence during occupational exposures was measured to be considerably lower than Hawleys estimate of 35 mgcnr
In Dermal Exposure Assessment Principles and Applications (EPA 1992) 1EPA recommends a soil adherence range of 02 to 1 mgcm2 For typical exposure to outdoor soil DEP (1995) recommends a soil adherence value of 051 mgcnr2 All of these values are consistent with the adherence rates measured by Kissel et al (1996) suggesting that soil loadings greater than 10 mgcnr during outdoor activities such as fanning are not realistic
In addition it is unlikely that hand-to-mouth contact would occur at Hawleys estimated loading rate It is instead likely that individuals who have a soil loading of this magnitude would not pick up food or put their hands in their mouths before washing or wiping their hands to remove the excess soil
According to Sheppard (1995) it may be reasonable to assume that mouthing behavior could occur at a loading rate of 10 mgcnr As this loading rale is at the upper end of the range of soil loading rates supported by both EPA and DEP and is higher than the highest soil loading rates reported by Kissel et al for the hands of farmers or any other adult exposure this soil loading rate has been used in combination with Hawleys other assumptions to derive an enhanced soil ingestion rate for farmers
If one substitutes the value of 10 mgcm2 for Hawleys assumption of 35 mgcm2 and continues to use Hawleys other exposure assumptions the resulting enhanced outdoor soil ingestion rate is 137 nigday For the purposes of the Housatonic River risk assessment GE proposes to use this more empirically-based enhanced adult soil ingestion rate of 137 ingday for the adult fanner
Derma] Absorption Rate for PCBs
In Comment 62 of their final comments on the Proposal for Human Health Risk Assessment for the Housatonic River the Agencies stated that they disagree with the use of dermal ilbsorption values of 146 percent and 143 percent proposed by GE for soils and sediment respectively The Agencies reconinnended instead that GE use a dermal absorption factor of 14 percent unless GE provides a credible and relevant justification for an alternative dermal absorption factor GE believes that a dermal absorption factor of 14 percent is not justifiable for the Housatonic River risk assessment due to limitations of the study upon which it is based and site-specific factors that indicate that such an estimate likely overstates actual absorption of PCBs from soils and sediments at this site
The dermal absorption values originally proposed by GE for soils and sediment were calculated by ChemRisk based on data from Roy et al (1990) As discussed in detail in the EPAs (1992) Dermal Exposure Assessment Guidance Principles and Applications Roy et al (1990) studied percutaneous absorption of tetrachlorobiphenyl (TCB) through human skin (in vitro) TCB was applied to human skin for 96 hours at a concentration of 1000 rngkg in soil with a low (045
Prni_GEGEHOUSAT2SW 002RESPCOMMHEAISSlEALTPA]U wpd 4 CHEMRlSK bullbullA DIVISION OF IVICL AH ENHART
percent) organic carbon content Absorption through human skin was 736 percent after 96 hours of exposure but negligible after only eight hours of exposure Roy et al (1990) also studied absorption from soil by rat skin in vitro and in vivo Total in vitro absorption from high (1122 percent) organic carbon content soil over 96 hours was 964 percent while absorption from low organic carbon soil in vitro in rats was 3195 percent over 96 hours For low organic carbon soil the absorption for the rat in vivo was 497 percent absorption after 96 hours
In its analysis EPA (1992) adjusted the Roy et al data to derive estimates of in vivo absorption of TCB in humans based on 24-hour exposure This was accomplished by adjusting the data to reflect differences between in vitro and in vivo tests rat and human skin and organic carbon content of the soil The adjusted percent TCB absorbed from soil was estimated to range from 063 percent for soil with high organic carbon content to 21 percent for soil with low organic carbon content Considering the uncertainty in these estimates EPA (1992) recommended a range of 06 percent to 6 percent for the percent of TCB dermally absorbed from the soil Moreover by comparing the Roy et al (1990) data to in vivo data from other bioavailability studies using other PCBs EPA (1992) concluded that the uptake of TCB was similar to that of other PCBs and that the range of 06 percent to 6 percent absorption for TCB is generally appropriate for PCBs
As these data indicate the dermal absorption of PCBs in soil is highly dependent on the organic carbon content of the soil GE proposed to account for this dependency by extrapolating from the Roy et al data to the relatively high site-specific organic carbon content of soils and sediments at the site DEP (1993) had previously agreed that it was appropriate to derive dermal absorption factors based on site-specific organic carbon content data as long as the organic carbon values used were based on reliable dala Because there are substantial data on the organic carbon contents of site soils and sediments GE proposed to use site-specific dermal absorption factors based on extrapolations of the Roy et al (1990) findings
In Comment 62 the Agencies stated that they no longer support the site-specific dermal absorption values previously derived by GE due to the findings of a study by Wester et al (1993) which indicated that dermal absorption of PCBs may be higher than that estimated by EPA using the Roy et al (1990) data The Wester et al (1993) study was designed to measure the extent to which Aroclors 1242 and 1254 would partition out of soil and be absorbed through the skin Wester et al (1993) added radio-labeled Aroclor 1242 and Aroclor 1234 to soil containing 26 percent sand 26 percent clay 48 percent silt and 09 percent organic carbon content Soils were mixed by hand to final concentrations of 44 mgkg Aroclor 1242 and 23 mgkg Aroclor 1254 These soils were then applied to the clipped abdominal skin of adult female rhesus monkeys for a period of 24 hours in a manner that would prevent the animals from licking or scratching at the skirt and would prevent exfoliated skin from contaminating urine or feces The skin site was covered with a non-occlusive cover that permitted air and moisture to move freely to and from the skin but retained the soil at the application site Urine and feces were collected during the exposure period After 24 hours skin
Proi_GEGEHOVSArumW2MSPCOMMVHEAISSUEALTPARiwpltl bull CHEMRlSK - A DIVISION OF MCLARENHART
was washed and urine and feces were periodically measured and analyzed for PCBs for 34 days following exposure
Percutaneous absorption was determined by urinary and fecal excretion following topical and intravenous administration Based on their measured recoveries combined with excretion efficiency data previously measured at their laboratory Wester et al (1993) concluded that the percutaneous absorptions of Aroclor 1242 and Aroclor 1254 from soil were 138 plusmn 27 percent and 141 + 10 percent of dose respectively Recovery of PCBs from skin was 83 percent for Aroclor 1242 and 72 percent for Aroclor 1254 most of the recovered dose was in the residual soil indicating that the PCBs had remained bound to soil during that 24-hour period rather than adsorbing to skin
While the Wester et al (1993) study was a well-conducted study that used appropriate experimental methodology there are several aspects of the study that limit its usefulness as a basis for developing dermal absorption factors for this site-specific risk assessment First Wester et al (1993) evaluated soils that had an organic carbon content of 09 percent and they did not test for variations in dermal absorption from soils with higher organic carbon contents This organic carbon content is very low and is not consistent with the levels of organic carbon content found in soils and sediments of the Housatonic River and its floodplain (ranging from 01 - 26 percent with arithmetic means of 50 and 53 percent for soils and sediments respectively) It is likely based on the clear trends shown in the Roy et al (1990) data that if higher levels of organic carbon had been tested by Wester et al (1993) the result would have been lower levels of percutaneous absorption
Second Wester et al (1993) applied soil to the animals skin at a rate of 40 ing soilcm2 skin (resulting in PCB concentrations on the skin of 175 ug PCBcm for Aroclor 1242 and 091 pg PCBcm2 for Aroclor 1254) This application rate is substantially greater than the adherence rates measured by Kissel et al (1996) or considered appropriate by DEP or EPA This higher rate of application may have increased the absorption of PCBs through the skin
Third the study used freshly spiked commercial PCB mixtures As discussed by EPA (1996b) in its reassessment of the carcinogenic potential of environmental PCB mixtures the composition of PCB mixtures changes over time through differential partitioning and chemical transformation of the component congeners For example congeners of lower chlorine content tend to be more volatile and also more soluble in water with rates of vaporization and relative water solubilities varying over several orders of magnitude between congeners These processes of volatilization and dissolution would appear to reduce the relative dermal absorption of a weathered PCB mixture compared to that of a freshly spiked sample In addition a weathered PCB mixture should form a tighter affinity to an environmental soil matrix over time further reducing its availability to become dermally absorbed
Finally Guy and Hadgraft (1987) reported that the permeability of skin in various parts of the body may be highly variable They reported that studies of hydrocortisone malathion and parathion have
ProjJ3DGEHOUSATU5laquoU02RESKOMMHEAISSUEALTPARlwpd - CHEMRlSK - A DIVISION OF McLARENHART
indicated that absorption across leg and forearm skin is similar but that the skin of the trunk is 25 times more permeable than the skin of the forearm or leg If this is also the case for PCBs it may be reasonable to conclude that absorption through the abdominal skin of the Wester at al (1993) monkeys may overestimate absorption through the skin of the arms or legs by as much as a factor of 25 If this were shown to be the case the result would be a dermal absorption of approximately 6 percent similar to the absorption factor recommended by EPA (1992) based on the Roy et al (1990) study for low carbon content soils over 24 hours of exposure
While the Wester et al (1993) study was a well conducted study the above-outlined limitations and uncertainties undermine its usefulness for this site-specific risk assessment In addition EPA has convened a dermal workgroup to evaluate the dermal absorption of PCBs and make recommendations for a revised absorption factor if appropriate This work group has not yet made a final recommendation When the work group has finished its analysis and EPA makes a recommendation on this issue GE will review that recommendation and all available data on dermal absorption of PCBs If however such a recommendation has not been made by the time that the risk assessment is conducted GE proposes to use the upper bound of current Agency guidance 6 percent for the evaluation of dermal absorption of PCBs from soil and sediment
References
Arnold DL F Bryce R Stapley PP McGuire D Burns JR Tanner and K Karpinski 1993a lexicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part 1A Prebreeding phase - clinical health findings Fd Chem Toxicol 31799-810
Arnold DL F Bryce K Karpinski J Mes S Fernie H Tryphonas J Truelove PP McGuire D Burns JR Tanner R Stapley ZZ Zawidzka and D Basford 1993b Toxicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part IB Prebreeding phase - clinical and analytical laboratory findings Fd Chem Toxicol 31811-824
Arnold D L F Bryce PP McGuire R Stapley JR Tanner E Wrenshall J Mes S Fernie H Tryphonas S Hayward and S Malcolm 1995 Toxicological consequences of Aroclor 1254 ingestion by female rhesus (Macaco mulatto) monkeys Part 2 Reproduction and infant findings Fd Chem Toxicol 33(6)457-474
DEP 1995 Guidance for Disposal Site Risk Characterization - In Support of the Massachusetts Contingency Plan - Interim Final Policy Massachusetts Department of Environmental Protection Bureau of Waste Site Cleanup and Office of Research and Standards Boston MA WSCORS-95shy141 July
DEP 1993 Memorandum to Catherine Wanat Project Manager WEROfrom Meg Harvey ORS Re Review of Revised Risk Assessment to Evaluate Need for Short-Term Measures in the 10-Year
ProjJDEGEHOliSATU5raquo3002RESrcOMMHEAISSUEALTPAIUwpltl CHEMRlSK - A DIVISION OF McLARENHART
Floodplain of the Housatonic River Massachusetts Department of Environmental Protection Office of Research and Standards Boston MA August 5
EFA 1996a Exposure Factors Handbook Volume I of III General Factors - Review Draft US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-95002Ba August
EPA 1996b Proposed Guidelines for Carcinogen Risk Assessment US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-92003C April
EPA 1992Dermal Exposure Assessment Principles and Applications US Environmental Protection Agency Office of Research and Development Washington DC EPA6008-9101 IB January
Guy RH and J Hadgraft 1987 Principles of skin permeability relevant to chemical exposure PB89-130009 NIOSH Grant K01-OH-00017 National Technical Information Service US Department of Commerce Springfield VA
Hawley JK 1985 Assessment of health risk from exposure to contaminated soil Risk Analysis 5289-302
IRIS 1997 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
IRIS 1994 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
Kissel JC KY Richter and RA Fenske 1996 Field measurement of dermal soil loading attributable to various activities Implications for exposure assessment Risk Anal 16 (1) 115-125
Roy TA JJ Yang AI Krueger and CR Mackerer 1990 Percutaneous absorption of neat 2378-tetrachlorodibenzo-p-dioxin (TCDD) and TCDD sorbed on soils Toxicology 10( I )308
Sheppard SC 1995 Parameter values to model the soil ingestion pathway Environmental Monitoring and Assessment 3427-44
Tryphonas H S Hayward L OGrady JCK Loo DL Arnold F Bryce and ZZ Zawidzka 1989 Immunotoxicity studies of PCB (Aroclor 1254) in the adult rhesus (Macaco mulatto) monkey - Preliminary report Int J Immunoph 11 (2) 199-206
PrOLGEGEHOllSAT2m002VRESPCOMMHEAlSSllEALTPAR2wpltj laquo CHEMRlSK bullbull A DIVISION OF McLARENHART
Tiyphonas H MI Luster G Schiffinan LL Dawson M Hodgen D Germolec S Hayward F Bryce JCK Loo F Mandy and DL Arnold 199 la Effect ofchronic exposure of PCB (Aroclor 1254) on specific and nonspecific immune parameters in the rhesus (Macaca mulatto) monkey FundAppl Toxicol 16773-786
Tiyphonas H MI Luster KL White PH Naylor MR EKlos GR Burleson D Germolec M Hodgen S Hayward and DL Arnold 1991b Effects of PCB (Aroclorreg 1254) on non-specific immune parameters in rhesus (Macaca mulatto) monkeys Int Immunoph 13(6)639-648
Wester RC HI Maibach L Sedik and J Melendres 1993 Percutaneous absorption of PCBs from soil In vivo rhesus monkey in vitro human skin and biding to powdered human stratum corneum Journal of Toxicology and Environmental Health 39375-282
Piuj_GEGEHOLPSATU5raquo3 (raquo2RESPCOMMHEAJSSUEAJ_TPAR2 wpd CHEMRjISK1 bullbull A DIVISION OF MCLARENHART
ATTACHMENT B
SCHEDULE - HUMAN HEALTH FOR HOUSATONIC
Deliverable (vith explanatory notes) Due Date
1 Baekcalculated Risk-Based Concentrations (RBCs) for PCBs for Residential Scenario 30 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in soil for the residential scenario taking into account Attachment A ambient air and indoor dust exposures and the potential presence of a garden It will also present all exposure and toxicity parameter values used in deriving those RBCs In addition it will include an evaluation of exposures to PCBs from lawn mowing and a description of the methodology used in that evaluation
Backcaiculated RBCs for PCBs for Other Scenarios 60 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in the pertinent media for the scenarios described Attachment A beiow together with all exposure and toxicity parameter values used in deriving those RBCs
o General recreational o Canoeing Q Swimming o Dirt hiking o Current commercial use o Current agricultural use o Utility worker o Construction worker o Fish consumption (from recreational fishing)
- 2 shy
Deliverable (with explanatory notes) Lme uate
3 Proposal Addendum Regarding Useable Data Other COPCs and Other Biota January 30 1998
This subrnittal will present the results of andor proposals for several tasks in the risk assessment process
a Data evaluation This subrnittal will present the results of the data evaluation as described in Section 3 of the Risk Assessment Proposal and will include a summarization of useable data This evaluation will necessarily be based on available data and thus will not be able to take account of the results of any additional Phase IIRFI investigations that may be required by the Agencies The data evaluation is estimated to take approximately 2-3 months and must be completed before the selection of other (non-PCB) Chemicals of Potential Concern (COPCs) car- be conducted
b Proposal on other COPCs This subrnittal will also present a proposal regarding other (non-PCB) COPCs It will include
o Identification of other COPCs based on the data evaluation results and the selection criteria described in the Proposal (including comparison to upstream levels)
o Dose-response assessment and proposal of toxicity values for these COPCs o Proposal of RAFs and other chemical-specific exposure parameters for these COPCs o Identification of areas where these COPCs have been detected in concentrations exceeding
upstream levels and o Identification of pertinent exposure scenarios for those areas
These tasks will take approximately 2 months after completion of the data evaluation
c Proposal regarding consumption of other biota This submittal will further include a proposal for the evaluation of consumption of biota other than fish It will include a proposal as to the specific species to be evaluated the method of evaluation (quantitative or qualitative) and the parameter values to be used in the quantitative evaluations (Note This item may have to be postponed to a later date if GE has not received from the Agencies the results of the Univ of Mass fiddlehead fern study in the time for consideration prior to the due date for this subrnittal)
-3 shy
Deliverable (with explanatory notes)
4 Backcalculated RBCs for Other COPCs for Relevant Scenarios
This subrnittal will present the backcalculated RBCs for the other identified COPCs in the pertinent media for the exposure scenarios identified as relevant to the areas where such COPCs have been detected It will also present all exposure and toxieity parameter values used in deriving those COPCs
Backcaiculated RBCs for Consumption of Other Biota
This subrnitta will present the backcalculated RBCs for the consumption of biota other than fish These RBCs win be presented for those species for which quantitative evaluation was conducted (The qualitative evaluation of other species will be included in the final risk assessment report)
6 Interim Risk Assessment Report - Application of RBCs Based on Current Use
This subrnkta will provide an Interim report on the risk assessment It will include a brief summary of the approach used and the prior submittals including the exposure scenarios and RBCs for each scenario It will also present sample forward risk calculations for each scenario using a dummy Exposure Point Concentration (EPC) It will further present the results of the application of the RBCs for PCBs (and other COPCs where applicable) to the relevant exposure points under current use assumptions This will include
o Identification of current uses of the site (by area) and the applicable exposure scenario based on such use o Identification of exposure points for each scenario based on current use o Calculation of EPCs for each exposure point (for PCBs and other COPCs where measured)
including a justification for the method of calculating them o Comparison of EPCs to applicable RBCs for each exposure point o Conclusion for each exposure point regarding presence of significant risk for applicable scenario and o Brief discussion of uncertainties and risk perspective
30 days from Agencies approval of proposal or- other COPCs (hern 3b)
30 days from Agencies approval of proposal for evaluation of consumption of other biota (Item 3c)
75 days from Agencies approval of Item 1 2 4 or 5 whichever is latest
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
- 5 shy
Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
percent) organic carbon content Absorption through human skin was 736 percent after 96 hours of exposure but negligible after only eight hours of exposure Roy et al (1990) also studied absorption from soil by rat skin in vitro and in vivo Total in vitro absorption from high (1122 percent) organic carbon content soil over 96 hours was 964 percent while absorption from low organic carbon soil in vitro in rats was 3195 percent over 96 hours For low organic carbon soil the absorption for the rat in vivo was 497 percent absorption after 96 hours
In its analysis EPA (1992) adjusted the Roy et al data to derive estimates of in vivo absorption of TCB in humans based on 24-hour exposure This was accomplished by adjusting the data to reflect differences between in vitro and in vivo tests rat and human skin and organic carbon content of the soil The adjusted percent TCB absorbed from soil was estimated to range from 063 percent for soil with high organic carbon content to 21 percent for soil with low organic carbon content Considering the uncertainty in these estimates EPA (1992) recommended a range of 06 percent to 6 percent for the percent of TCB dermally absorbed from the soil Moreover by comparing the Roy et al (1990) data to in vivo data from other bioavailability studies using other PCBs EPA (1992) concluded that the uptake of TCB was similar to that of other PCBs and that the range of 06 percent to 6 percent absorption for TCB is generally appropriate for PCBs
As these data indicate the dermal absorption of PCBs in soil is highly dependent on the organic carbon content of the soil GE proposed to account for this dependency by extrapolating from the Roy et al data to the relatively high site-specific organic carbon content of soils and sediments at the site DEP (1993) had previously agreed that it was appropriate to derive dermal absorption factors based on site-specific organic carbon content data as long as the organic carbon values used were based on reliable dala Because there are substantial data on the organic carbon contents of site soils and sediments GE proposed to use site-specific dermal absorption factors based on extrapolations of the Roy et al (1990) findings
In Comment 62 the Agencies stated that they no longer support the site-specific dermal absorption values previously derived by GE due to the findings of a study by Wester et al (1993) which indicated that dermal absorption of PCBs may be higher than that estimated by EPA using the Roy et al (1990) data The Wester et al (1993) study was designed to measure the extent to which Aroclors 1242 and 1254 would partition out of soil and be absorbed through the skin Wester et al (1993) added radio-labeled Aroclor 1242 and Aroclor 1234 to soil containing 26 percent sand 26 percent clay 48 percent silt and 09 percent organic carbon content Soils were mixed by hand to final concentrations of 44 mgkg Aroclor 1242 and 23 mgkg Aroclor 1254 These soils were then applied to the clipped abdominal skin of adult female rhesus monkeys for a period of 24 hours in a manner that would prevent the animals from licking or scratching at the skirt and would prevent exfoliated skin from contaminating urine or feces The skin site was covered with a non-occlusive cover that permitted air and moisture to move freely to and from the skin but retained the soil at the application site Urine and feces were collected during the exposure period After 24 hours skin
Proi_GEGEHOVSArumW2MSPCOMMVHEAISSUEALTPARiwpltl bull CHEMRlSK - A DIVISION OF MCLARENHART
was washed and urine and feces were periodically measured and analyzed for PCBs for 34 days following exposure
Percutaneous absorption was determined by urinary and fecal excretion following topical and intravenous administration Based on their measured recoveries combined with excretion efficiency data previously measured at their laboratory Wester et al (1993) concluded that the percutaneous absorptions of Aroclor 1242 and Aroclor 1254 from soil were 138 plusmn 27 percent and 141 + 10 percent of dose respectively Recovery of PCBs from skin was 83 percent for Aroclor 1242 and 72 percent for Aroclor 1254 most of the recovered dose was in the residual soil indicating that the PCBs had remained bound to soil during that 24-hour period rather than adsorbing to skin
While the Wester et al (1993) study was a well-conducted study that used appropriate experimental methodology there are several aspects of the study that limit its usefulness as a basis for developing dermal absorption factors for this site-specific risk assessment First Wester et al (1993) evaluated soils that had an organic carbon content of 09 percent and they did not test for variations in dermal absorption from soils with higher organic carbon contents This organic carbon content is very low and is not consistent with the levels of organic carbon content found in soils and sediments of the Housatonic River and its floodplain (ranging from 01 - 26 percent with arithmetic means of 50 and 53 percent for soils and sediments respectively) It is likely based on the clear trends shown in the Roy et al (1990) data that if higher levels of organic carbon had been tested by Wester et al (1993) the result would have been lower levels of percutaneous absorption
Second Wester et al (1993) applied soil to the animals skin at a rate of 40 ing soilcm2 skin (resulting in PCB concentrations on the skin of 175 ug PCBcm for Aroclor 1242 and 091 pg PCBcm2 for Aroclor 1254) This application rate is substantially greater than the adherence rates measured by Kissel et al (1996) or considered appropriate by DEP or EPA This higher rate of application may have increased the absorption of PCBs through the skin
Third the study used freshly spiked commercial PCB mixtures As discussed by EPA (1996b) in its reassessment of the carcinogenic potential of environmental PCB mixtures the composition of PCB mixtures changes over time through differential partitioning and chemical transformation of the component congeners For example congeners of lower chlorine content tend to be more volatile and also more soluble in water with rates of vaporization and relative water solubilities varying over several orders of magnitude between congeners These processes of volatilization and dissolution would appear to reduce the relative dermal absorption of a weathered PCB mixture compared to that of a freshly spiked sample In addition a weathered PCB mixture should form a tighter affinity to an environmental soil matrix over time further reducing its availability to become dermally absorbed
Finally Guy and Hadgraft (1987) reported that the permeability of skin in various parts of the body may be highly variable They reported that studies of hydrocortisone malathion and parathion have
ProjJ3DGEHOUSATU5laquoU02RESKOMMHEAISSUEALTPARlwpd - CHEMRlSK - A DIVISION OF McLARENHART
indicated that absorption across leg and forearm skin is similar but that the skin of the trunk is 25 times more permeable than the skin of the forearm or leg If this is also the case for PCBs it may be reasonable to conclude that absorption through the abdominal skin of the Wester at al (1993) monkeys may overestimate absorption through the skin of the arms or legs by as much as a factor of 25 If this were shown to be the case the result would be a dermal absorption of approximately 6 percent similar to the absorption factor recommended by EPA (1992) based on the Roy et al (1990) study for low carbon content soils over 24 hours of exposure
While the Wester et al (1993) study was a well conducted study the above-outlined limitations and uncertainties undermine its usefulness for this site-specific risk assessment In addition EPA has convened a dermal workgroup to evaluate the dermal absorption of PCBs and make recommendations for a revised absorption factor if appropriate This work group has not yet made a final recommendation When the work group has finished its analysis and EPA makes a recommendation on this issue GE will review that recommendation and all available data on dermal absorption of PCBs If however such a recommendation has not been made by the time that the risk assessment is conducted GE proposes to use the upper bound of current Agency guidance 6 percent for the evaluation of dermal absorption of PCBs from soil and sediment
References
Arnold DL F Bryce R Stapley PP McGuire D Burns JR Tanner and K Karpinski 1993a lexicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part 1A Prebreeding phase - clinical health findings Fd Chem Toxicol 31799-810
Arnold DL F Bryce K Karpinski J Mes S Fernie H Tryphonas J Truelove PP McGuire D Burns JR Tanner R Stapley ZZ Zawidzka and D Basford 1993b Toxicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part IB Prebreeding phase - clinical and analytical laboratory findings Fd Chem Toxicol 31811-824
Arnold D L F Bryce PP McGuire R Stapley JR Tanner E Wrenshall J Mes S Fernie H Tryphonas S Hayward and S Malcolm 1995 Toxicological consequences of Aroclor 1254 ingestion by female rhesus (Macaco mulatto) monkeys Part 2 Reproduction and infant findings Fd Chem Toxicol 33(6)457-474
DEP 1995 Guidance for Disposal Site Risk Characterization - In Support of the Massachusetts Contingency Plan - Interim Final Policy Massachusetts Department of Environmental Protection Bureau of Waste Site Cleanup and Office of Research and Standards Boston MA WSCORS-95shy141 July
DEP 1993 Memorandum to Catherine Wanat Project Manager WEROfrom Meg Harvey ORS Re Review of Revised Risk Assessment to Evaluate Need for Short-Term Measures in the 10-Year
ProjJDEGEHOliSATU5raquo3002RESrcOMMHEAISSUEALTPAIUwpltl CHEMRlSK - A DIVISION OF McLARENHART
Floodplain of the Housatonic River Massachusetts Department of Environmental Protection Office of Research and Standards Boston MA August 5
EFA 1996a Exposure Factors Handbook Volume I of III General Factors - Review Draft US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-95002Ba August
EPA 1996b Proposed Guidelines for Carcinogen Risk Assessment US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-92003C April
EPA 1992Dermal Exposure Assessment Principles and Applications US Environmental Protection Agency Office of Research and Development Washington DC EPA6008-9101 IB January
Guy RH and J Hadgraft 1987 Principles of skin permeability relevant to chemical exposure PB89-130009 NIOSH Grant K01-OH-00017 National Technical Information Service US Department of Commerce Springfield VA
Hawley JK 1985 Assessment of health risk from exposure to contaminated soil Risk Analysis 5289-302
IRIS 1997 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
IRIS 1994 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
Kissel JC KY Richter and RA Fenske 1996 Field measurement of dermal soil loading attributable to various activities Implications for exposure assessment Risk Anal 16 (1) 115-125
Roy TA JJ Yang AI Krueger and CR Mackerer 1990 Percutaneous absorption of neat 2378-tetrachlorodibenzo-p-dioxin (TCDD) and TCDD sorbed on soils Toxicology 10( I )308
Sheppard SC 1995 Parameter values to model the soil ingestion pathway Environmental Monitoring and Assessment 3427-44
Tryphonas H S Hayward L OGrady JCK Loo DL Arnold F Bryce and ZZ Zawidzka 1989 Immunotoxicity studies of PCB (Aroclor 1254) in the adult rhesus (Macaco mulatto) monkey - Preliminary report Int J Immunoph 11 (2) 199-206
PrOLGEGEHOllSAT2m002VRESPCOMMHEAlSSllEALTPAR2wpltj laquo CHEMRlSK bullbull A DIVISION OF McLARENHART
Tiyphonas H MI Luster G Schiffinan LL Dawson M Hodgen D Germolec S Hayward F Bryce JCK Loo F Mandy and DL Arnold 199 la Effect ofchronic exposure of PCB (Aroclor 1254) on specific and nonspecific immune parameters in the rhesus (Macaca mulatto) monkey FundAppl Toxicol 16773-786
Tiyphonas H MI Luster KL White PH Naylor MR EKlos GR Burleson D Germolec M Hodgen S Hayward and DL Arnold 1991b Effects of PCB (Aroclorreg 1254) on non-specific immune parameters in rhesus (Macaca mulatto) monkeys Int Immunoph 13(6)639-648
Wester RC HI Maibach L Sedik and J Melendres 1993 Percutaneous absorption of PCBs from soil In vivo rhesus monkey in vitro human skin and biding to powdered human stratum corneum Journal of Toxicology and Environmental Health 39375-282
Piuj_GEGEHOLPSATU5raquo3 (raquo2RESPCOMMHEAJSSUEAJ_TPAR2 wpd CHEMRjISK1 bullbull A DIVISION OF MCLARENHART
ATTACHMENT B
SCHEDULE - HUMAN HEALTH FOR HOUSATONIC
Deliverable (vith explanatory notes) Due Date
1 Baekcalculated Risk-Based Concentrations (RBCs) for PCBs for Residential Scenario 30 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in soil for the residential scenario taking into account Attachment A ambient air and indoor dust exposures and the potential presence of a garden It will also present all exposure and toxicity parameter values used in deriving those RBCs In addition it will include an evaluation of exposures to PCBs from lawn mowing and a description of the methodology used in that evaluation
Backcaiculated RBCs for PCBs for Other Scenarios 60 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in the pertinent media for the scenarios described Attachment A beiow together with all exposure and toxicity parameter values used in deriving those RBCs
o General recreational o Canoeing Q Swimming o Dirt hiking o Current commercial use o Current agricultural use o Utility worker o Construction worker o Fish consumption (from recreational fishing)
- 2 shy
Deliverable (with explanatory notes) Lme uate
3 Proposal Addendum Regarding Useable Data Other COPCs and Other Biota January 30 1998
This subrnittal will present the results of andor proposals for several tasks in the risk assessment process
a Data evaluation This subrnittal will present the results of the data evaluation as described in Section 3 of the Risk Assessment Proposal and will include a summarization of useable data This evaluation will necessarily be based on available data and thus will not be able to take account of the results of any additional Phase IIRFI investigations that may be required by the Agencies The data evaluation is estimated to take approximately 2-3 months and must be completed before the selection of other (non-PCB) Chemicals of Potential Concern (COPCs) car- be conducted
b Proposal on other COPCs This subrnittal will also present a proposal regarding other (non-PCB) COPCs It will include
o Identification of other COPCs based on the data evaluation results and the selection criteria described in the Proposal (including comparison to upstream levels)
o Dose-response assessment and proposal of toxicity values for these COPCs o Proposal of RAFs and other chemical-specific exposure parameters for these COPCs o Identification of areas where these COPCs have been detected in concentrations exceeding
upstream levels and o Identification of pertinent exposure scenarios for those areas
These tasks will take approximately 2 months after completion of the data evaluation
c Proposal regarding consumption of other biota This submittal will further include a proposal for the evaluation of consumption of biota other than fish It will include a proposal as to the specific species to be evaluated the method of evaluation (quantitative or qualitative) and the parameter values to be used in the quantitative evaluations (Note This item may have to be postponed to a later date if GE has not received from the Agencies the results of the Univ of Mass fiddlehead fern study in the time for consideration prior to the due date for this subrnittal)
-3 shy
Deliverable (with explanatory notes)
4 Backcalculated RBCs for Other COPCs for Relevant Scenarios
This subrnittal will present the backcalculated RBCs for the other identified COPCs in the pertinent media for the exposure scenarios identified as relevant to the areas where such COPCs have been detected It will also present all exposure and toxieity parameter values used in deriving those COPCs
Backcaiculated RBCs for Consumption of Other Biota
This subrnitta will present the backcalculated RBCs for the consumption of biota other than fish These RBCs win be presented for those species for which quantitative evaluation was conducted (The qualitative evaluation of other species will be included in the final risk assessment report)
6 Interim Risk Assessment Report - Application of RBCs Based on Current Use
This subrnkta will provide an Interim report on the risk assessment It will include a brief summary of the approach used and the prior submittals including the exposure scenarios and RBCs for each scenario It will also present sample forward risk calculations for each scenario using a dummy Exposure Point Concentration (EPC) It will further present the results of the application of the RBCs for PCBs (and other COPCs where applicable) to the relevant exposure points under current use assumptions This will include
o Identification of current uses of the site (by area) and the applicable exposure scenario based on such use o Identification of exposure points for each scenario based on current use o Calculation of EPCs for each exposure point (for PCBs and other COPCs where measured)
including a justification for the method of calculating them o Comparison of EPCs to applicable RBCs for each exposure point o Conclusion for each exposure point regarding presence of significant risk for applicable scenario and o Brief discussion of uncertainties and risk perspective
30 days from Agencies approval of proposal or- other COPCs (hern 3b)
30 days from Agencies approval of proposal for evaluation of consumption of other biota (Item 3c)
75 days from Agencies approval of Item 1 2 4 or 5 whichever is latest
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
- 5 shy
Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
was washed and urine and feces were periodically measured and analyzed for PCBs for 34 days following exposure
Percutaneous absorption was determined by urinary and fecal excretion following topical and intravenous administration Based on their measured recoveries combined with excretion efficiency data previously measured at their laboratory Wester et al (1993) concluded that the percutaneous absorptions of Aroclor 1242 and Aroclor 1254 from soil were 138 plusmn 27 percent and 141 + 10 percent of dose respectively Recovery of PCBs from skin was 83 percent for Aroclor 1242 and 72 percent for Aroclor 1254 most of the recovered dose was in the residual soil indicating that the PCBs had remained bound to soil during that 24-hour period rather than adsorbing to skin
While the Wester et al (1993) study was a well-conducted study that used appropriate experimental methodology there are several aspects of the study that limit its usefulness as a basis for developing dermal absorption factors for this site-specific risk assessment First Wester et al (1993) evaluated soils that had an organic carbon content of 09 percent and they did not test for variations in dermal absorption from soils with higher organic carbon contents This organic carbon content is very low and is not consistent with the levels of organic carbon content found in soils and sediments of the Housatonic River and its floodplain (ranging from 01 - 26 percent with arithmetic means of 50 and 53 percent for soils and sediments respectively) It is likely based on the clear trends shown in the Roy et al (1990) data that if higher levels of organic carbon had been tested by Wester et al (1993) the result would have been lower levels of percutaneous absorption
Second Wester et al (1993) applied soil to the animals skin at a rate of 40 ing soilcm2 skin (resulting in PCB concentrations on the skin of 175 ug PCBcm for Aroclor 1242 and 091 pg PCBcm2 for Aroclor 1254) This application rate is substantially greater than the adherence rates measured by Kissel et al (1996) or considered appropriate by DEP or EPA This higher rate of application may have increased the absorption of PCBs through the skin
Third the study used freshly spiked commercial PCB mixtures As discussed by EPA (1996b) in its reassessment of the carcinogenic potential of environmental PCB mixtures the composition of PCB mixtures changes over time through differential partitioning and chemical transformation of the component congeners For example congeners of lower chlorine content tend to be more volatile and also more soluble in water with rates of vaporization and relative water solubilities varying over several orders of magnitude between congeners These processes of volatilization and dissolution would appear to reduce the relative dermal absorption of a weathered PCB mixture compared to that of a freshly spiked sample In addition a weathered PCB mixture should form a tighter affinity to an environmental soil matrix over time further reducing its availability to become dermally absorbed
Finally Guy and Hadgraft (1987) reported that the permeability of skin in various parts of the body may be highly variable They reported that studies of hydrocortisone malathion and parathion have
ProjJ3DGEHOUSATU5laquoU02RESKOMMHEAISSUEALTPARlwpd - CHEMRlSK - A DIVISION OF McLARENHART
indicated that absorption across leg and forearm skin is similar but that the skin of the trunk is 25 times more permeable than the skin of the forearm or leg If this is also the case for PCBs it may be reasonable to conclude that absorption through the abdominal skin of the Wester at al (1993) monkeys may overestimate absorption through the skin of the arms or legs by as much as a factor of 25 If this were shown to be the case the result would be a dermal absorption of approximately 6 percent similar to the absorption factor recommended by EPA (1992) based on the Roy et al (1990) study for low carbon content soils over 24 hours of exposure
While the Wester et al (1993) study was a well conducted study the above-outlined limitations and uncertainties undermine its usefulness for this site-specific risk assessment In addition EPA has convened a dermal workgroup to evaluate the dermal absorption of PCBs and make recommendations for a revised absorption factor if appropriate This work group has not yet made a final recommendation When the work group has finished its analysis and EPA makes a recommendation on this issue GE will review that recommendation and all available data on dermal absorption of PCBs If however such a recommendation has not been made by the time that the risk assessment is conducted GE proposes to use the upper bound of current Agency guidance 6 percent for the evaluation of dermal absorption of PCBs from soil and sediment
References
Arnold DL F Bryce R Stapley PP McGuire D Burns JR Tanner and K Karpinski 1993a lexicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part 1A Prebreeding phase - clinical health findings Fd Chem Toxicol 31799-810
Arnold DL F Bryce K Karpinski J Mes S Fernie H Tryphonas J Truelove PP McGuire D Burns JR Tanner R Stapley ZZ Zawidzka and D Basford 1993b Toxicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part IB Prebreeding phase - clinical and analytical laboratory findings Fd Chem Toxicol 31811-824
Arnold D L F Bryce PP McGuire R Stapley JR Tanner E Wrenshall J Mes S Fernie H Tryphonas S Hayward and S Malcolm 1995 Toxicological consequences of Aroclor 1254 ingestion by female rhesus (Macaco mulatto) monkeys Part 2 Reproduction and infant findings Fd Chem Toxicol 33(6)457-474
DEP 1995 Guidance for Disposal Site Risk Characterization - In Support of the Massachusetts Contingency Plan - Interim Final Policy Massachusetts Department of Environmental Protection Bureau of Waste Site Cleanup and Office of Research and Standards Boston MA WSCORS-95shy141 July
DEP 1993 Memorandum to Catherine Wanat Project Manager WEROfrom Meg Harvey ORS Re Review of Revised Risk Assessment to Evaluate Need for Short-Term Measures in the 10-Year
ProjJDEGEHOliSATU5raquo3002RESrcOMMHEAISSUEALTPAIUwpltl CHEMRlSK - A DIVISION OF McLARENHART
Floodplain of the Housatonic River Massachusetts Department of Environmental Protection Office of Research and Standards Boston MA August 5
EFA 1996a Exposure Factors Handbook Volume I of III General Factors - Review Draft US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-95002Ba August
EPA 1996b Proposed Guidelines for Carcinogen Risk Assessment US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-92003C April
EPA 1992Dermal Exposure Assessment Principles and Applications US Environmental Protection Agency Office of Research and Development Washington DC EPA6008-9101 IB January
Guy RH and J Hadgraft 1987 Principles of skin permeability relevant to chemical exposure PB89-130009 NIOSH Grant K01-OH-00017 National Technical Information Service US Department of Commerce Springfield VA
Hawley JK 1985 Assessment of health risk from exposure to contaminated soil Risk Analysis 5289-302
IRIS 1997 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
IRIS 1994 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
Kissel JC KY Richter and RA Fenske 1996 Field measurement of dermal soil loading attributable to various activities Implications for exposure assessment Risk Anal 16 (1) 115-125
Roy TA JJ Yang AI Krueger and CR Mackerer 1990 Percutaneous absorption of neat 2378-tetrachlorodibenzo-p-dioxin (TCDD) and TCDD sorbed on soils Toxicology 10( I )308
Sheppard SC 1995 Parameter values to model the soil ingestion pathway Environmental Monitoring and Assessment 3427-44
Tryphonas H S Hayward L OGrady JCK Loo DL Arnold F Bryce and ZZ Zawidzka 1989 Immunotoxicity studies of PCB (Aroclor 1254) in the adult rhesus (Macaco mulatto) monkey - Preliminary report Int J Immunoph 11 (2) 199-206
PrOLGEGEHOllSAT2m002VRESPCOMMHEAlSSllEALTPAR2wpltj laquo CHEMRlSK bullbull A DIVISION OF McLARENHART
Tiyphonas H MI Luster G Schiffinan LL Dawson M Hodgen D Germolec S Hayward F Bryce JCK Loo F Mandy and DL Arnold 199 la Effect ofchronic exposure of PCB (Aroclor 1254) on specific and nonspecific immune parameters in the rhesus (Macaca mulatto) monkey FundAppl Toxicol 16773-786
Tiyphonas H MI Luster KL White PH Naylor MR EKlos GR Burleson D Germolec M Hodgen S Hayward and DL Arnold 1991b Effects of PCB (Aroclorreg 1254) on non-specific immune parameters in rhesus (Macaca mulatto) monkeys Int Immunoph 13(6)639-648
Wester RC HI Maibach L Sedik and J Melendres 1993 Percutaneous absorption of PCBs from soil In vivo rhesus monkey in vitro human skin and biding to powdered human stratum corneum Journal of Toxicology and Environmental Health 39375-282
Piuj_GEGEHOLPSATU5raquo3 (raquo2RESPCOMMHEAJSSUEAJ_TPAR2 wpd CHEMRjISK1 bullbull A DIVISION OF MCLARENHART
ATTACHMENT B
SCHEDULE - HUMAN HEALTH FOR HOUSATONIC
Deliverable (vith explanatory notes) Due Date
1 Baekcalculated Risk-Based Concentrations (RBCs) for PCBs for Residential Scenario 30 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in soil for the residential scenario taking into account Attachment A ambient air and indoor dust exposures and the potential presence of a garden It will also present all exposure and toxicity parameter values used in deriving those RBCs In addition it will include an evaluation of exposures to PCBs from lawn mowing and a description of the methodology used in that evaluation
Backcaiculated RBCs for PCBs for Other Scenarios 60 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in the pertinent media for the scenarios described Attachment A beiow together with all exposure and toxicity parameter values used in deriving those RBCs
o General recreational o Canoeing Q Swimming o Dirt hiking o Current commercial use o Current agricultural use o Utility worker o Construction worker o Fish consumption (from recreational fishing)
- 2 shy
Deliverable (with explanatory notes) Lme uate
3 Proposal Addendum Regarding Useable Data Other COPCs and Other Biota January 30 1998
This subrnittal will present the results of andor proposals for several tasks in the risk assessment process
a Data evaluation This subrnittal will present the results of the data evaluation as described in Section 3 of the Risk Assessment Proposal and will include a summarization of useable data This evaluation will necessarily be based on available data and thus will not be able to take account of the results of any additional Phase IIRFI investigations that may be required by the Agencies The data evaluation is estimated to take approximately 2-3 months and must be completed before the selection of other (non-PCB) Chemicals of Potential Concern (COPCs) car- be conducted
b Proposal on other COPCs This subrnittal will also present a proposal regarding other (non-PCB) COPCs It will include
o Identification of other COPCs based on the data evaluation results and the selection criteria described in the Proposal (including comparison to upstream levels)
o Dose-response assessment and proposal of toxicity values for these COPCs o Proposal of RAFs and other chemical-specific exposure parameters for these COPCs o Identification of areas where these COPCs have been detected in concentrations exceeding
upstream levels and o Identification of pertinent exposure scenarios for those areas
These tasks will take approximately 2 months after completion of the data evaluation
c Proposal regarding consumption of other biota This submittal will further include a proposal for the evaluation of consumption of biota other than fish It will include a proposal as to the specific species to be evaluated the method of evaluation (quantitative or qualitative) and the parameter values to be used in the quantitative evaluations (Note This item may have to be postponed to a later date if GE has not received from the Agencies the results of the Univ of Mass fiddlehead fern study in the time for consideration prior to the due date for this subrnittal)
-3 shy
Deliverable (with explanatory notes)
4 Backcalculated RBCs for Other COPCs for Relevant Scenarios
This subrnittal will present the backcalculated RBCs for the other identified COPCs in the pertinent media for the exposure scenarios identified as relevant to the areas where such COPCs have been detected It will also present all exposure and toxieity parameter values used in deriving those COPCs
Backcaiculated RBCs for Consumption of Other Biota
This subrnitta will present the backcalculated RBCs for the consumption of biota other than fish These RBCs win be presented for those species for which quantitative evaluation was conducted (The qualitative evaluation of other species will be included in the final risk assessment report)
6 Interim Risk Assessment Report - Application of RBCs Based on Current Use
This subrnkta will provide an Interim report on the risk assessment It will include a brief summary of the approach used and the prior submittals including the exposure scenarios and RBCs for each scenario It will also present sample forward risk calculations for each scenario using a dummy Exposure Point Concentration (EPC) It will further present the results of the application of the RBCs for PCBs (and other COPCs where applicable) to the relevant exposure points under current use assumptions This will include
o Identification of current uses of the site (by area) and the applicable exposure scenario based on such use o Identification of exposure points for each scenario based on current use o Calculation of EPCs for each exposure point (for PCBs and other COPCs where measured)
including a justification for the method of calculating them o Comparison of EPCs to applicable RBCs for each exposure point o Conclusion for each exposure point regarding presence of significant risk for applicable scenario and o Brief discussion of uncertainties and risk perspective
30 days from Agencies approval of proposal or- other COPCs (hern 3b)
30 days from Agencies approval of proposal for evaluation of consumption of other biota (Item 3c)
75 days from Agencies approval of Item 1 2 4 or 5 whichever is latest
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
- 5 shy
Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
indicated that absorption across leg and forearm skin is similar but that the skin of the trunk is 25 times more permeable than the skin of the forearm or leg If this is also the case for PCBs it may be reasonable to conclude that absorption through the abdominal skin of the Wester at al (1993) monkeys may overestimate absorption through the skin of the arms or legs by as much as a factor of 25 If this were shown to be the case the result would be a dermal absorption of approximately 6 percent similar to the absorption factor recommended by EPA (1992) based on the Roy et al (1990) study for low carbon content soils over 24 hours of exposure
While the Wester et al (1993) study was a well conducted study the above-outlined limitations and uncertainties undermine its usefulness for this site-specific risk assessment In addition EPA has convened a dermal workgroup to evaluate the dermal absorption of PCBs and make recommendations for a revised absorption factor if appropriate This work group has not yet made a final recommendation When the work group has finished its analysis and EPA makes a recommendation on this issue GE will review that recommendation and all available data on dermal absorption of PCBs If however such a recommendation has not been made by the time that the risk assessment is conducted GE proposes to use the upper bound of current Agency guidance 6 percent for the evaluation of dermal absorption of PCBs from soil and sediment
References
Arnold DL F Bryce R Stapley PP McGuire D Burns JR Tanner and K Karpinski 1993a lexicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part 1A Prebreeding phase - clinical health findings Fd Chem Toxicol 31799-810
Arnold DL F Bryce K Karpinski J Mes S Fernie H Tryphonas J Truelove PP McGuire D Burns JR Tanner R Stapley ZZ Zawidzka and D Basford 1993b Toxicological consequences of Aroclor 1254 ingestion by female Rhesus (Macaco mulatto) monkeys Part IB Prebreeding phase - clinical and analytical laboratory findings Fd Chem Toxicol 31811-824
Arnold D L F Bryce PP McGuire R Stapley JR Tanner E Wrenshall J Mes S Fernie H Tryphonas S Hayward and S Malcolm 1995 Toxicological consequences of Aroclor 1254 ingestion by female rhesus (Macaco mulatto) monkeys Part 2 Reproduction and infant findings Fd Chem Toxicol 33(6)457-474
DEP 1995 Guidance for Disposal Site Risk Characterization - In Support of the Massachusetts Contingency Plan - Interim Final Policy Massachusetts Department of Environmental Protection Bureau of Waste Site Cleanup and Office of Research and Standards Boston MA WSCORS-95shy141 July
DEP 1993 Memorandum to Catherine Wanat Project Manager WEROfrom Meg Harvey ORS Re Review of Revised Risk Assessment to Evaluate Need for Short-Term Measures in the 10-Year
ProjJDEGEHOliSATU5raquo3002RESrcOMMHEAISSUEALTPAIUwpltl CHEMRlSK - A DIVISION OF McLARENHART
Floodplain of the Housatonic River Massachusetts Department of Environmental Protection Office of Research and Standards Boston MA August 5
EFA 1996a Exposure Factors Handbook Volume I of III General Factors - Review Draft US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-95002Ba August
EPA 1996b Proposed Guidelines for Carcinogen Risk Assessment US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-92003C April
EPA 1992Dermal Exposure Assessment Principles and Applications US Environmental Protection Agency Office of Research and Development Washington DC EPA6008-9101 IB January
Guy RH and J Hadgraft 1987 Principles of skin permeability relevant to chemical exposure PB89-130009 NIOSH Grant K01-OH-00017 National Technical Information Service US Department of Commerce Springfield VA
Hawley JK 1985 Assessment of health risk from exposure to contaminated soil Risk Analysis 5289-302
IRIS 1997 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
IRIS 1994 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
Kissel JC KY Richter and RA Fenske 1996 Field measurement of dermal soil loading attributable to various activities Implications for exposure assessment Risk Anal 16 (1) 115-125
Roy TA JJ Yang AI Krueger and CR Mackerer 1990 Percutaneous absorption of neat 2378-tetrachlorodibenzo-p-dioxin (TCDD) and TCDD sorbed on soils Toxicology 10( I )308
Sheppard SC 1995 Parameter values to model the soil ingestion pathway Environmental Monitoring and Assessment 3427-44
Tryphonas H S Hayward L OGrady JCK Loo DL Arnold F Bryce and ZZ Zawidzka 1989 Immunotoxicity studies of PCB (Aroclor 1254) in the adult rhesus (Macaco mulatto) monkey - Preliminary report Int J Immunoph 11 (2) 199-206
PrOLGEGEHOllSAT2m002VRESPCOMMHEAlSSllEALTPAR2wpltj laquo CHEMRlSK bullbull A DIVISION OF McLARENHART
Tiyphonas H MI Luster G Schiffinan LL Dawson M Hodgen D Germolec S Hayward F Bryce JCK Loo F Mandy and DL Arnold 199 la Effect ofchronic exposure of PCB (Aroclor 1254) on specific and nonspecific immune parameters in the rhesus (Macaca mulatto) monkey FundAppl Toxicol 16773-786
Tiyphonas H MI Luster KL White PH Naylor MR EKlos GR Burleson D Germolec M Hodgen S Hayward and DL Arnold 1991b Effects of PCB (Aroclorreg 1254) on non-specific immune parameters in rhesus (Macaca mulatto) monkeys Int Immunoph 13(6)639-648
Wester RC HI Maibach L Sedik and J Melendres 1993 Percutaneous absorption of PCBs from soil In vivo rhesus monkey in vitro human skin and biding to powdered human stratum corneum Journal of Toxicology and Environmental Health 39375-282
Piuj_GEGEHOLPSATU5raquo3 (raquo2RESPCOMMHEAJSSUEAJ_TPAR2 wpd CHEMRjISK1 bullbull A DIVISION OF MCLARENHART
ATTACHMENT B
SCHEDULE - HUMAN HEALTH FOR HOUSATONIC
Deliverable (vith explanatory notes) Due Date
1 Baekcalculated Risk-Based Concentrations (RBCs) for PCBs for Residential Scenario 30 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in soil for the residential scenario taking into account Attachment A ambient air and indoor dust exposures and the potential presence of a garden It will also present all exposure and toxicity parameter values used in deriving those RBCs In addition it will include an evaluation of exposures to PCBs from lawn mowing and a description of the methodology used in that evaluation
Backcaiculated RBCs for PCBs for Other Scenarios 60 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in the pertinent media for the scenarios described Attachment A beiow together with all exposure and toxicity parameter values used in deriving those RBCs
o General recreational o Canoeing Q Swimming o Dirt hiking o Current commercial use o Current agricultural use o Utility worker o Construction worker o Fish consumption (from recreational fishing)
- 2 shy
Deliverable (with explanatory notes) Lme uate
3 Proposal Addendum Regarding Useable Data Other COPCs and Other Biota January 30 1998
This subrnittal will present the results of andor proposals for several tasks in the risk assessment process
a Data evaluation This subrnittal will present the results of the data evaluation as described in Section 3 of the Risk Assessment Proposal and will include a summarization of useable data This evaluation will necessarily be based on available data and thus will not be able to take account of the results of any additional Phase IIRFI investigations that may be required by the Agencies The data evaluation is estimated to take approximately 2-3 months and must be completed before the selection of other (non-PCB) Chemicals of Potential Concern (COPCs) car- be conducted
b Proposal on other COPCs This subrnittal will also present a proposal regarding other (non-PCB) COPCs It will include
o Identification of other COPCs based on the data evaluation results and the selection criteria described in the Proposal (including comparison to upstream levels)
o Dose-response assessment and proposal of toxicity values for these COPCs o Proposal of RAFs and other chemical-specific exposure parameters for these COPCs o Identification of areas where these COPCs have been detected in concentrations exceeding
upstream levels and o Identification of pertinent exposure scenarios for those areas
These tasks will take approximately 2 months after completion of the data evaluation
c Proposal regarding consumption of other biota This submittal will further include a proposal for the evaluation of consumption of biota other than fish It will include a proposal as to the specific species to be evaluated the method of evaluation (quantitative or qualitative) and the parameter values to be used in the quantitative evaluations (Note This item may have to be postponed to a later date if GE has not received from the Agencies the results of the Univ of Mass fiddlehead fern study in the time for consideration prior to the due date for this subrnittal)
-3 shy
Deliverable (with explanatory notes)
4 Backcalculated RBCs for Other COPCs for Relevant Scenarios
This subrnittal will present the backcalculated RBCs for the other identified COPCs in the pertinent media for the exposure scenarios identified as relevant to the areas where such COPCs have been detected It will also present all exposure and toxieity parameter values used in deriving those COPCs
Backcaiculated RBCs for Consumption of Other Biota
This subrnitta will present the backcalculated RBCs for the consumption of biota other than fish These RBCs win be presented for those species for which quantitative evaluation was conducted (The qualitative evaluation of other species will be included in the final risk assessment report)
6 Interim Risk Assessment Report - Application of RBCs Based on Current Use
This subrnkta will provide an Interim report on the risk assessment It will include a brief summary of the approach used and the prior submittals including the exposure scenarios and RBCs for each scenario It will also present sample forward risk calculations for each scenario using a dummy Exposure Point Concentration (EPC) It will further present the results of the application of the RBCs for PCBs (and other COPCs where applicable) to the relevant exposure points under current use assumptions This will include
o Identification of current uses of the site (by area) and the applicable exposure scenario based on such use o Identification of exposure points for each scenario based on current use o Calculation of EPCs for each exposure point (for PCBs and other COPCs where measured)
including a justification for the method of calculating them o Comparison of EPCs to applicable RBCs for each exposure point o Conclusion for each exposure point regarding presence of significant risk for applicable scenario and o Brief discussion of uncertainties and risk perspective
30 days from Agencies approval of proposal or- other COPCs (hern 3b)
30 days from Agencies approval of proposal for evaluation of consumption of other biota (Item 3c)
75 days from Agencies approval of Item 1 2 4 or 5 whichever is latest
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
- 5 shy
Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
Floodplain of the Housatonic River Massachusetts Department of Environmental Protection Office of Research and Standards Boston MA August 5
EFA 1996a Exposure Factors Handbook Volume I of III General Factors - Review Draft US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-95002Ba August
EPA 1996b Proposed Guidelines for Carcinogen Risk Assessment US Environmental Protection Agency Office of Research and Development Washington DC EPA600P-92003C April
EPA 1992Dermal Exposure Assessment Principles and Applications US Environmental Protection Agency Office of Research and Development Washington DC EPA6008-9101 IB January
Guy RH and J Hadgraft 1987 Principles of skin permeability relevant to chemical exposure PB89-130009 NIOSH Grant K01-OH-00017 National Technical Information Service US Department of Commerce Springfield VA
Hawley JK 1985 Assessment of health risk from exposure to contaminated soil Risk Analysis 5289-302
IRIS 1997 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
IRIS 1994 Chemical Search for PCBs Integrated Risk Information Service US Environmental Protection Agency Cincinnati OH and National Research Library of Medicine Bethesda MD
Kissel JC KY Richter and RA Fenske 1996 Field measurement of dermal soil loading attributable to various activities Implications for exposure assessment Risk Anal 16 (1) 115-125
Roy TA JJ Yang AI Krueger and CR Mackerer 1990 Percutaneous absorption of neat 2378-tetrachlorodibenzo-p-dioxin (TCDD) and TCDD sorbed on soils Toxicology 10( I )308
Sheppard SC 1995 Parameter values to model the soil ingestion pathway Environmental Monitoring and Assessment 3427-44
Tryphonas H S Hayward L OGrady JCK Loo DL Arnold F Bryce and ZZ Zawidzka 1989 Immunotoxicity studies of PCB (Aroclor 1254) in the adult rhesus (Macaco mulatto) monkey - Preliminary report Int J Immunoph 11 (2) 199-206
PrOLGEGEHOllSAT2m002VRESPCOMMHEAlSSllEALTPAR2wpltj laquo CHEMRlSK bullbull A DIVISION OF McLARENHART
Tiyphonas H MI Luster G Schiffinan LL Dawson M Hodgen D Germolec S Hayward F Bryce JCK Loo F Mandy and DL Arnold 199 la Effect ofchronic exposure of PCB (Aroclor 1254) on specific and nonspecific immune parameters in the rhesus (Macaca mulatto) monkey FundAppl Toxicol 16773-786
Tiyphonas H MI Luster KL White PH Naylor MR EKlos GR Burleson D Germolec M Hodgen S Hayward and DL Arnold 1991b Effects of PCB (Aroclorreg 1254) on non-specific immune parameters in rhesus (Macaca mulatto) monkeys Int Immunoph 13(6)639-648
Wester RC HI Maibach L Sedik and J Melendres 1993 Percutaneous absorption of PCBs from soil In vivo rhesus monkey in vitro human skin and biding to powdered human stratum corneum Journal of Toxicology and Environmental Health 39375-282
Piuj_GEGEHOLPSATU5raquo3 (raquo2RESPCOMMHEAJSSUEAJ_TPAR2 wpd CHEMRjISK1 bullbull A DIVISION OF MCLARENHART
ATTACHMENT B
SCHEDULE - HUMAN HEALTH FOR HOUSATONIC
Deliverable (vith explanatory notes) Due Date
1 Baekcalculated Risk-Based Concentrations (RBCs) for PCBs for Residential Scenario 30 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in soil for the residential scenario taking into account Attachment A ambient air and indoor dust exposures and the potential presence of a garden It will also present all exposure and toxicity parameter values used in deriving those RBCs In addition it will include an evaluation of exposures to PCBs from lawn mowing and a description of the methodology used in that evaluation
Backcaiculated RBCs for PCBs for Other Scenarios 60 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in the pertinent media for the scenarios described Attachment A beiow together with all exposure and toxicity parameter values used in deriving those RBCs
o General recreational o Canoeing Q Swimming o Dirt hiking o Current commercial use o Current agricultural use o Utility worker o Construction worker o Fish consumption (from recreational fishing)
- 2 shy
Deliverable (with explanatory notes) Lme uate
3 Proposal Addendum Regarding Useable Data Other COPCs and Other Biota January 30 1998
This subrnittal will present the results of andor proposals for several tasks in the risk assessment process
a Data evaluation This subrnittal will present the results of the data evaluation as described in Section 3 of the Risk Assessment Proposal and will include a summarization of useable data This evaluation will necessarily be based on available data and thus will not be able to take account of the results of any additional Phase IIRFI investigations that may be required by the Agencies The data evaluation is estimated to take approximately 2-3 months and must be completed before the selection of other (non-PCB) Chemicals of Potential Concern (COPCs) car- be conducted
b Proposal on other COPCs This subrnittal will also present a proposal regarding other (non-PCB) COPCs It will include
o Identification of other COPCs based on the data evaluation results and the selection criteria described in the Proposal (including comparison to upstream levels)
o Dose-response assessment and proposal of toxicity values for these COPCs o Proposal of RAFs and other chemical-specific exposure parameters for these COPCs o Identification of areas where these COPCs have been detected in concentrations exceeding
upstream levels and o Identification of pertinent exposure scenarios for those areas
These tasks will take approximately 2 months after completion of the data evaluation
c Proposal regarding consumption of other biota This submittal will further include a proposal for the evaluation of consumption of biota other than fish It will include a proposal as to the specific species to be evaluated the method of evaluation (quantitative or qualitative) and the parameter values to be used in the quantitative evaluations (Note This item may have to be postponed to a later date if GE has not received from the Agencies the results of the Univ of Mass fiddlehead fern study in the time for consideration prior to the due date for this subrnittal)
-3 shy
Deliverable (with explanatory notes)
4 Backcalculated RBCs for Other COPCs for Relevant Scenarios
This subrnittal will present the backcalculated RBCs for the other identified COPCs in the pertinent media for the exposure scenarios identified as relevant to the areas where such COPCs have been detected It will also present all exposure and toxieity parameter values used in deriving those COPCs
Backcaiculated RBCs for Consumption of Other Biota
This subrnitta will present the backcalculated RBCs for the consumption of biota other than fish These RBCs win be presented for those species for which quantitative evaluation was conducted (The qualitative evaluation of other species will be included in the final risk assessment report)
6 Interim Risk Assessment Report - Application of RBCs Based on Current Use
This subrnkta will provide an Interim report on the risk assessment It will include a brief summary of the approach used and the prior submittals including the exposure scenarios and RBCs for each scenario It will also present sample forward risk calculations for each scenario using a dummy Exposure Point Concentration (EPC) It will further present the results of the application of the RBCs for PCBs (and other COPCs where applicable) to the relevant exposure points under current use assumptions This will include
o Identification of current uses of the site (by area) and the applicable exposure scenario based on such use o Identification of exposure points for each scenario based on current use o Calculation of EPCs for each exposure point (for PCBs and other COPCs where measured)
including a justification for the method of calculating them o Comparison of EPCs to applicable RBCs for each exposure point o Conclusion for each exposure point regarding presence of significant risk for applicable scenario and o Brief discussion of uncertainties and risk perspective
30 days from Agencies approval of proposal or- other COPCs (hern 3b)
30 days from Agencies approval of proposal for evaluation of consumption of other biota (Item 3c)
75 days from Agencies approval of Item 1 2 4 or 5 whichever is latest
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
- 5 shy
Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
Tiyphonas H MI Luster G Schiffinan LL Dawson M Hodgen D Germolec S Hayward F Bryce JCK Loo F Mandy and DL Arnold 199 la Effect ofchronic exposure of PCB (Aroclor 1254) on specific and nonspecific immune parameters in the rhesus (Macaca mulatto) monkey FundAppl Toxicol 16773-786
Tiyphonas H MI Luster KL White PH Naylor MR EKlos GR Burleson D Germolec M Hodgen S Hayward and DL Arnold 1991b Effects of PCB (Aroclorreg 1254) on non-specific immune parameters in rhesus (Macaca mulatto) monkeys Int Immunoph 13(6)639-648
Wester RC HI Maibach L Sedik and J Melendres 1993 Percutaneous absorption of PCBs from soil In vivo rhesus monkey in vitro human skin and biding to powdered human stratum corneum Journal of Toxicology and Environmental Health 39375-282
Piuj_GEGEHOLPSATU5raquo3 (raquo2RESPCOMMHEAJSSUEAJ_TPAR2 wpd CHEMRjISK1 bullbull A DIVISION OF MCLARENHART
ATTACHMENT B
SCHEDULE - HUMAN HEALTH FOR HOUSATONIC
Deliverable (vith explanatory notes) Due Date
1 Baekcalculated Risk-Based Concentrations (RBCs) for PCBs for Residential Scenario 30 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in soil for the residential scenario taking into account Attachment A ambient air and indoor dust exposures and the potential presence of a garden It will also present all exposure and toxicity parameter values used in deriving those RBCs In addition it will include an evaluation of exposures to PCBs from lawn mowing and a description of the methodology used in that evaluation
Backcaiculated RBCs for PCBs for Other Scenarios 60 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in the pertinent media for the scenarios described Attachment A beiow together with all exposure and toxicity parameter values used in deriving those RBCs
o General recreational o Canoeing Q Swimming o Dirt hiking o Current commercial use o Current agricultural use o Utility worker o Construction worker o Fish consumption (from recreational fishing)
- 2 shy
Deliverable (with explanatory notes) Lme uate
3 Proposal Addendum Regarding Useable Data Other COPCs and Other Biota January 30 1998
This subrnittal will present the results of andor proposals for several tasks in the risk assessment process
a Data evaluation This subrnittal will present the results of the data evaluation as described in Section 3 of the Risk Assessment Proposal and will include a summarization of useable data This evaluation will necessarily be based on available data and thus will not be able to take account of the results of any additional Phase IIRFI investigations that may be required by the Agencies The data evaluation is estimated to take approximately 2-3 months and must be completed before the selection of other (non-PCB) Chemicals of Potential Concern (COPCs) car- be conducted
b Proposal on other COPCs This subrnittal will also present a proposal regarding other (non-PCB) COPCs It will include
o Identification of other COPCs based on the data evaluation results and the selection criteria described in the Proposal (including comparison to upstream levels)
o Dose-response assessment and proposal of toxicity values for these COPCs o Proposal of RAFs and other chemical-specific exposure parameters for these COPCs o Identification of areas where these COPCs have been detected in concentrations exceeding
upstream levels and o Identification of pertinent exposure scenarios for those areas
These tasks will take approximately 2 months after completion of the data evaluation
c Proposal regarding consumption of other biota This submittal will further include a proposal for the evaluation of consumption of biota other than fish It will include a proposal as to the specific species to be evaluated the method of evaluation (quantitative or qualitative) and the parameter values to be used in the quantitative evaluations (Note This item may have to be postponed to a later date if GE has not received from the Agencies the results of the Univ of Mass fiddlehead fern study in the time for consideration prior to the due date for this subrnittal)
-3 shy
Deliverable (with explanatory notes)
4 Backcalculated RBCs for Other COPCs for Relevant Scenarios
This subrnittal will present the backcalculated RBCs for the other identified COPCs in the pertinent media for the exposure scenarios identified as relevant to the areas where such COPCs have been detected It will also present all exposure and toxieity parameter values used in deriving those COPCs
Backcaiculated RBCs for Consumption of Other Biota
This subrnitta will present the backcalculated RBCs for the consumption of biota other than fish These RBCs win be presented for those species for which quantitative evaluation was conducted (The qualitative evaluation of other species will be included in the final risk assessment report)
6 Interim Risk Assessment Report - Application of RBCs Based on Current Use
This subrnkta will provide an Interim report on the risk assessment It will include a brief summary of the approach used and the prior submittals including the exposure scenarios and RBCs for each scenario It will also present sample forward risk calculations for each scenario using a dummy Exposure Point Concentration (EPC) It will further present the results of the application of the RBCs for PCBs (and other COPCs where applicable) to the relevant exposure points under current use assumptions This will include
o Identification of current uses of the site (by area) and the applicable exposure scenario based on such use o Identification of exposure points for each scenario based on current use o Calculation of EPCs for each exposure point (for PCBs and other COPCs where measured)
including a justification for the method of calculating them o Comparison of EPCs to applicable RBCs for each exposure point o Conclusion for each exposure point regarding presence of significant risk for applicable scenario and o Brief discussion of uncertainties and risk perspective
30 days from Agencies approval of proposal or- other COPCs (hern 3b)
30 days from Agencies approval of proposal for evaluation of consumption of other biota (Item 3c)
75 days from Agencies approval of Item 1 2 4 or 5 whichever is latest
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
- 5 shy
Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
ATTACHMENT B
SCHEDULE - HUMAN HEALTH FOR HOUSATONIC
Deliverable (vith explanatory notes) Due Date
1 Baekcalculated Risk-Based Concentrations (RBCs) for PCBs for Residential Scenario 30 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in soil for the residential scenario taking into account Attachment A ambient air and indoor dust exposures and the potential presence of a garden It will also present all exposure and toxicity parameter values used in deriving those RBCs In addition it will include an evaluation of exposures to PCBs from lawn mowing and a description of the methodology used in that evaluation
Backcaiculated RBCs for PCBs for Other Scenarios 60 days from Agencies determination on proposals in
This subrnittal will present the backcalculated RBCs for PCBs in the pertinent media for the scenarios described Attachment A beiow together with all exposure and toxicity parameter values used in deriving those RBCs
o General recreational o Canoeing Q Swimming o Dirt hiking o Current commercial use o Current agricultural use o Utility worker o Construction worker o Fish consumption (from recreational fishing)
- 2 shy
Deliverable (with explanatory notes) Lme uate
3 Proposal Addendum Regarding Useable Data Other COPCs and Other Biota January 30 1998
This subrnittal will present the results of andor proposals for several tasks in the risk assessment process
a Data evaluation This subrnittal will present the results of the data evaluation as described in Section 3 of the Risk Assessment Proposal and will include a summarization of useable data This evaluation will necessarily be based on available data and thus will not be able to take account of the results of any additional Phase IIRFI investigations that may be required by the Agencies The data evaluation is estimated to take approximately 2-3 months and must be completed before the selection of other (non-PCB) Chemicals of Potential Concern (COPCs) car- be conducted
b Proposal on other COPCs This subrnittal will also present a proposal regarding other (non-PCB) COPCs It will include
o Identification of other COPCs based on the data evaluation results and the selection criteria described in the Proposal (including comparison to upstream levels)
o Dose-response assessment and proposal of toxicity values for these COPCs o Proposal of RAFs and other chemical-specific exposure parameters for these COPCs o Identification of areas where these COPCs have been detected in concentrations exceeding
upstream levels and o Identification of pertinent exposure scenarios for those areas
These tasks will take approximately 2 months after completion of the data evaluation
c Proposal regarding consumption of other biota This submittal will further include a proposal for the evaluation of consumption of biota other than fish It will include a proposal as to the specific species to be evaluated the method of evaluation (quantitative or qualitative) and the parameter values to be used in the quantitative evaluations (Note This item may have to be postponed to a later date if GE has not received from the Agencies the results of the Univ of Mass fiddlehead fern study in the time for consideration prior to the due date for this subrnittal)
-3 shy
Deliverable (with explanatory notes)
4 Backcalculated RBCs for Other COPCs for Relevant Scenarios
This subrnittal will present the backcalculated RBCs for the other identified COPCs in the pertinent media for the exposure scenarios identified as relevant to the areas where such COPCs have been detected It will also present all exposure and toxieity parameter values used in deriving those COPCs
Backcaiculated RBCs for Consumption of Other Biota
This subrnitta will present the backcalculated RBCs for the consumption of biota other than fish These RBCs win be presented for those species for which quantitative evaluation was conducted (The qualitative evaluation of other species will be included in the final risk assessment report)
6 Interim Risk Assessment Report - Application of RBCs Based on Current Use
This subrnkta will provide an Interim report on the risk assessment It will include a brief summary of the approach used and the prior submittals including the exposure scenarios and RBCs for each scenario It will also present sample forward risk calculations for each scenario using a dummy Exposure Point Concentration (EPC) It will further present the results of the application of the RBCs for PCBs (and other COPCs where applicable) to the relevant exposure points under current use assumptions This will include
o Identification of current uses of the site (by area) and the applicable exposure scenario based on such use o Identification of exposure points for each scenario based on current use o Calculation of EPCs for each exposure point (for PCBs and other COPCs where measured)
including a justification for the method of calculating them o Comparison of EPCs to applicable RBCs for each exposure point o Conclusion for each exposure point regarding presence of significant risk for applicable scenario and o Brief discussion of uncertainties and risk perspective
30 days from Agencies approval of proposal or- other COPCs (hern 3b)
30 days from Agencies approval of proposal for evaluation of consumption of other biota (Item 3c)
75 days from Agencies approval of Item 1 2 4 or 5 whichever is latest
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
- 5 shy
Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
- 2 shy
Deliverable (with explanatory notes) Lme uate
3 Proposal Addendum Regarding Useable Data Other COPCs and Other Biota January 30 1998
This subrnittal will present the results of andor proposals for several tasks in the risk assessment process
a Data evaluation This subrnittal will present the results of the data evaluation as described in Section 3 of the Risk Assessment Proposal and will include a summarization of useable data This evaluation will necessarily be based on available data and thus will not be able to take account of the results of any additional Phase IIRFI investigations that may be required by the Agencies The data evaluation is estimated to take approximately 2-3 months and must be completed before the selection of other (non-PCB) Chemicals of Potential Concern (COPCs) car- be conducted
b Proposal on other COPCs This subrnittal will also present a proposal regarding other (non-PCB) COPCs It will include
o Identification of other COPCs based on the data evaluation results and the selection criteria described in the Proposal (including comparison to upstream levels)
o Dose-response assessment and proposal of toxicity values for these COPCs o Proposal of RAFs and other chemical-specific exposure parameters for these COPCs o Identification of areas where these COPCs have been detected in concentrations exceeding
upstream levels and o Identification of pertinent exposure scenarios for those areas
These tasks will take approximately 2 months after completion of the data evaluation
c Proposal regarding consumption of other biota This submittal will further include a proposal for the evaluation of consumption of biota other than fish It will include a proposal as to the specific species to be evaluated the method of evaluation (quantitative or qualitative) and the parameter values to be used in the quantitative evaluations (Note This item may have to be postponed to a later date if GE has not received from the Agencies the results of the Univ of Mass fiddlehead fern study in the time for consideration prior to the due date for this subrnittal)
-3 shy
Deliverable (with explanatory notes)
4 Backcalculated RBCs for Other COPCs for Relevant Scenarios
This subrnittal will present the backcalculated RBCs for the other identified COPCs in the pertinent media for the exposure scenarios identified as relevant to the areas where such COPCs have been detected It will also present all exposure and toxieity parameter values used in deriving those COPCs
Backcaiculated RBCs for Consumption of Other Biota
This subrnitta will present the backcalculated RBCs for the consumption of biota other than fish These RBCs win be presented for those species for which quantitative evaluation was conducted (The qualitative evaluation of other species will be included in the final risk assessment report)
6 Interim Risk Assessment Report - Application of RBCs Based on Current Use
This subrnkta will provide an Interim report on the risk assessment It will include a brief summary of the approach used and the prior submittals including the exposure scenarios and RBCs for each scenario It will also present sample forward risk calculations for each scenario using a dummy Exposure Point Concentration (EPC) It will further present the results of the application of the RBCs for PCBs (and other COPCs where applicable) to the relevant exposure points under current use assumptions This will include
o Identification of current uses of the site (by area) and the applicable exposure scenario based on such use o Identification of exposure points for each scenario based on current use o Calculation of EPCs for each exposure point (for PCBs and other COPCs where measured)
including a justification for the method of calculating them o Comparison of EPCs to applicable RBCs for each exposure point o Conclusion for each exposure point regarding presence of significant risk for applicable scenario and o Brief discussion of uncertainties and risk perspective
30 days from Agencies approval of proposal or- other COPCs (hern 3b)
30 days from Agencies approval of proposal for evaluation of consumption of other biota (Item 3c)
75 days from Agencies approval of Item 1 2 4 or 5 whichever is latest
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
- 5 shy
Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
-3 shy
Deliverable (with explanatory notes)
4 Backcalculated RBCs for Other COPCs for Relevant Scenarios
This subrnittal will present the backcalculated RBCs for the other identified COPCs in the pertinent media for the exposure scenarios identified as relevant to the areas where such COPCs have been detected It will also present all exposure and toxieity parameter values used in deriving those COPCs
Backcaiculated RBCs for Consumption of Other Biota
This subrnitta will present the backcalculated RBCs for the consumption of biota other than fish These RBCs win be presented for those species for which quantitative evaluation was conducted (The qualitative evaluation of other species will be included in the final risk assessment report)
6 Interim Risk Assessment Report - Application of RBCs Based on Current Use
This subrnkta will provide an Interim report on the risk assessment It will include a brief summary of the approach used and the prior submittals including the exposure scenarios and RBCs for each scenario It will also present sample forward risk calculations for each scenario using a dummy Exposure Point Concentration (EPC) It will further present the results of the application of the RBCs for PCBs (and other COPCs where applicable) to the relevant exposure points under current use assumptions This will include
o Identification of current uses of the site (by area) and the applicable exposure scenario based on such use o Identification of exposure points for each scenario based on current use o Calculation of EPCs for each exposure point (for PCBs and other COPCs where measured)
including a justification for the method of calculating them o Comparison of EPCs to applicable RBCs for each exposure point o Conclusion for each exposure point regarding presence of significant risk for applicable scenario and o Brief discussion of uncertainties and risk perspective
30 days from Agencies approval of proposal or- other COPCs (hern 3b)
30 days from Agencies approval of proposal for evaluation of consumption of other biota (Item 3c)
75 days from Agencies approval of Item 1 2 4 or 5 whichever is latest
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
- 5 shy
Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
= 4 =
Deliverable (with explanatory notes)
7 Identification of Foreseeable Future Uses of Site
This submitial will present the results of the mapping exercise to identify foreseeable future uses of the site It will require the performance of an on-siie survey and evaluation (in cooperation with the Agencies) to identify foreseeable future uses followed by the development of maps that show such uses for all areas within the site It is anticipated that the on-site survey would take place in Spring 1998 and that maps would then be developed presenting the results of the survey
8 Backcalculated RBCs for Foreseeable Future Commercial and Agricultural Uses
This subrnittal will present the backcalculated RBCs for PCBs (and other COPCs where relevant) in soil for foreseeable future commercial and agricultural uses of the floodplain These RBCs cannot be derived until after the mapping exercise in Item 7 is completed because some of the exposure parameters will depend on the results of the mapping exercise (eg portion of commercial property in floodplain portion of corn fields or grazing area in floodplain) This subrniital will include RBCs for different types of agricultural use
uue Date
Early Summer 1998 (specific date to be determined in conjunction with Agencies depending on timing of on-site survey)
30 days from Agencies approval of Item 7
- 5 shy
Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
- 5 shy
Deliverable (with explanatory Liue
9 Final Risk Assessment Report 90 days from Agencies approval of Item 8
This subrniital will be the final report on the risk assessment it will present a summary of the overall approach and assumptions used (including media of concern COPCs selected toxicity values used exposure scenarios evaluated and exposure assumptions used) It will again present sample forward risk calculations for each scenario using a dummy EPC It will further present the results of the application of the RBCs for all COPCs to the relevant exposure points under both current and foreseeable future use assumptions This will include
o Summary of the RBCs for each scenario and each COPC (where relevant) o Identification of exposure points for each scenario based on current use and EPCs for those
exposure points o Application of the RBCs to each exposure point based on current use o Identification of exposure points for each scenario based on foreseeable future use and EPCs for
those exposure points o Application of the RBCs to each exposure point based on foreseeable future use o Comparison of surface water EPCs to ambient water quality criteria for human health protection
from fish consumption o Conclusion for each exposure point regarding presence of significant risk for applicable scenario
based on both current and foreseeable future use This report will also include
o Uncertainty analysis o Qualitative evaluation of consumption of biota species that were not quantitatively evaluated o Risk perspective (including evaluation of subsistence fishing scenario) o Toxicological profiles (in Appendix)
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