Final

Second Five-Year Review Report

Shaw Avenue DUlllp Site Charles City

Floyd County, Iowa

August 2010

Region 7 United States Envil'onlllental Protection Agency

Kansas City, Kansas

Approved by:

Ce iii a--<.<l p1a--~ Date:

SIIA II' AVENUE I)UMP SITE SECONI) FIVE-YEAR REVIEW REI'OI{T

Table of Contents List of Acronyms ............................. ....... ........ ....... ... ................... .. ........... .... ........ ..... ........... .. ... .... . iv Executive Summary .............................................................................. ......... ........................... ES-I Five-Year Review Summary Form ............... .. ........... .. ........................ .. ...................... .. ........... ES-3 1.0 Introduction .................................................................... .................. ................................ "" I 2.0 Site Cluonology ......... ............. ..... ...... ...... ........ .... .................... .. .......... .............. ....... .......... .. 2 3.0 Background .......................................................................................................................... 3

3.1 Physical Characteristics ....... .. ........................................................... .. ............ .. ... .... ....... .. 3 3.2 Land and Resource Use .................................................................................................... 3 3.3 History of Contamination .. ......... ...................................................................................... 4 3.4 Initial Response ............. ...... ... ................................... ... ........ ...... ...................................... 5 3.5 Basis for Taking Action .................................................................................................... 6

4.0 Remedial Actions .. ..... .......... .. ....... .. .... ........ .... ..... ......... ............... ......... ..... ......... .. ............... 9 4.1 Remedy Selection ............................................................................................................. 9 4.2 Remedy Implementation ...... ...... ...... .......... ..... ... ........ .. .. ... ....... ..... .................................... 9 4.3 System Operation/Operation and Maintenance ................................................ .............. 10

5.0 Progress Since Last Review ....................................................... ....... ....... ................... ....... II 6.0 Five-Year Review Process .......... ........ ... ...... ....................... ...... ........................... .............. 12

6.1 Administrative Components ......... ...... ........... .. ........ .. ...... .. ................ .. .. .. ......... .. ............ 12 6.2 Community Involvement ....... ... .......... .. .......... .. ....... .... .. ......... .... .... ...... .... ...... ...... .. ..... .. . 12 6.3 Document Review ..... ... ... ... .. ................. ..... ................ .. .. ............ ... .. ..... .......................... 12 6.4 Data Review ....................................................................................... ............................ 12 6.5 Eva luation of Historical COC Concentration Trends ..................................................... 13 6.6 Site Inspection ..... ....... .............................. ... .................................... ... ... .... ........ ..... .. ...... 14 6.7 Interviews .. .... ... ...... ... ..................... .. ...................... ....................... ...... ... .. .. ... ...... .. ......... 16

7.0 Technical Assessment ........................................................................................................ 17 7.1 Question A: Is the remedy functioning as intended by the decision documents? ......... 17

7 .1 .1 Remedial Action Performance .. ............. .. .. .. .................. ......................................... 17 7.1.2 System Operations/O&M ........................................................................................ 18 7.1.3 Opportunities for Optimization ............................................................................... 19 7.1.4 Early Indicators of Potential Issues ......................................................................... 19 7 .1.5 Implementation of Institutional Controls and Other Measures ..... .......... ..... ...... ... .. 19

7.2 Question B: Are the exposure assumptions, toxicity data, cleanup levels, and remedial action objectives (RAOs) used at the time of the remedy selection still valid? ............. 19

7.2.1 Changes in Standards and To-Be-Considered Criteria ........... ............................ .... 20 7.2.2 Changes in Exposure Pathways ... ................ ........ ........... .. ................. ... .................. 20 7 .2.3 Changes in Toxicity and Other Contaminant Characteristics ........ .. ......... ........ .. .. .. 21 7.2.4 Changes in Risk Assessment Methods .................................................................... 22

7.3 Question C: Has any other information come to light that could call into question the protectiveness of the remedy? ......... ..... ..... ..... ... .. .. .. ...... .... ... ..... .... ....... ... ... ... ......... ... ..... 22

7.3.1 Ecological Risks ......... ......... ... ... ...................... ......... ... .... .. ... ..... ........... .... ............. .. 22 7.3.2 Natura l Disaster Impacts ................................ .. ....................................................... 22

SI·!/\ \V AVENUE DUMP SITE SECOND FIVE·YE,\R REVIEW REPORT

7.3.3 Any Other Information That Could Call Into Question the Protectiveness of the Remedy .. ...... ............... ........ ... ........... ................. ... .......... ........ .......... ........... ............ 23

7.4 Technical Assessment Summary ............ ...... ............. .... ... .. ... ........... ... ... ....... ....... .. .. ...... 23 8.0 Issues ..... ...... .. ................. ........................ ..... ................. .............. ............ .......... .................. 24 9.0 Recommendations and Follow-up Actions .. ............... .. .. .. ..... ... .. .. .. ..... ............ .. ............. ... 25 10.0 Protectiveness Statement .. .. ...... ... ... ... ..... ... ... ....... ..... ................. .... ..... ...... .. ....... ........... ...... 26 11.0 Next Review .......... .. ................. ......... ... ..................... ............ ................. ..... ........ ... ....... .... . 27

Tables

Table I: Recommendations and Follow-up Actions Table 2: Clu'onology of Site Events Table 3: Summary of Well Construction Details Table 4: Groundwater Monitoring Frequency and Analysis Table 5: Quarterly Groundwater Elevations Post OU I Remediation Groundwater Monitoring Table 6: Groundwater Monitoring Results Summary 2004 - 2009 Table 7: Daily Local Precipitation 2005 - 2009 Table 8: Changes in Chemical-Specific Standards Table 9: Changes in Federal MCLs Table 10: Changes in Iowa Action Levels Table II: Comparison of Oral Reference Doses Table 12: Comparison of Inhalation Reference Concentrations Table 13: Changes in Oral Cancer Slope Factors Table 14: Changes in Cancer Inhalation Unit Risk Table 15: Maintenance Items To Be Completed By PRJ>

Figlll'cs

Figure I: Site Location Figure 2: Site Layout Figure 3: Groundwater Flow - October 2009 Figure 4: Arsenic Concentrations MW-2 Figure 5: Arsenic Concent rations MW-6 Figure 6: Arsenic Concentrations MW-7 Figure 7: Arsenic Concentrations MW-8 Figure 8: Precipitation Comparison with Groundwater Elevations in the Alluvia l Wells of the

Upper Cedar Valley Aquifer Figure 9: Precipitation Comparison with Groundwater Elevations in the Bedrock Wells of the

Upper Cedar Valley Aquifer

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Attachments

Attachment I: Public Notice Attachment 2: Site Inspection Checklist Attachment 3: Photos Docllmenting Site Conditions Attachment 4: List of Documents Reviewed

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SHAW AVENUE DUivlP SITE SECOND FIVE-YE/\R REVIEW REPORT

List of Acronyms

AMSL

ARARs CENWK CERCLA

CFR COC CSF 1,2-DCA

EPA ESD FS lAC IDEQ IDNR IEUBK

LDL MCL mg/kg mg/L MW NA NCP

NPL NS O&M OU PCOC PCOR ppm PRG PRP PVC RAO RCRA RfC RiD

above mean sea level

Applicable or Relevant and Appropriate Requirements U.S . Army Corps of Engineers, Kansas City District

Comprehensive Environmental Response, Compensation, and Liability Act Code of Federal Regulations chemical of concel'll cancer slope factor 1,2-dichloroethane Environmental Protection Agency

Explanation of Significant Differences Feasibility Study Iowa Administrative Code Iowa Department of EnvirolUllental Quality Iowa Department of Natural Resources Integrated Exposure Uptake Biokinetic Model for Lead in Children instrument lowest detection limit Maximum Contaminant Level milligram per kilogram milligram per liter monitoring well not applicable National Contingency Plan National Priorities List not sampled

operation and maintenance Operable Unit potential chemical of concern Preliminary Closeout Report part per million Preliminary Remediation Goal Potentially Responsible Party

polyvinyl chloride remedial action objective Resource Conservation and Recovery Act reference concentration reterence dose

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RI Remedial Investigation

ROD Record of Decision

RPM Remedial Project Manager

SARA Superfund Amendments and Reauthorization Act 1,1,2-TCA I, I ,2-trichloroethane

pglL micrograms per liter VOC volatile organic compound

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SHAW AVENUE DUMP SITE SECOND FIVE-YEAR REVIEW REPORT

Executive SUlllmary

This is the second five-year review (FYR) for the Shaw Avenue Dump Site. The Shaw Avenue Dump Site is located on the southeastel'll edge of Charles City, Iowa, approximately 600 feet tl'om the Cedar River, near the intersection of Shaw Avenue and Clark Street. The site runs northeast to southwest and is approximately 2,000 feet long and approximately 525 feet wide. The Iowa Terminal Railroad tracks bound the site to the west. The site is fenced on the north and east sides and is bordered by the Cedar River to the south . The site occupies approximately 24 acres of the Cedar River 100-year floodplain. The site is owned by the city of Charles City.

The city of Charles City purchased the northel'll portion of the site in 1899 and continued to acquire sections until 1964. The site has been used for municipal waste disposal and disposal of sludge from the city wastewater treatment plant and was also used by Salsbury Laboratories, Inc., from 1949 to 1953 to di spose of chemical processing waste, consisting of arsenic and organic compounds from its animal pharmaceuticals business. Salsbury Laboratories discharged liquid wastes to the city wastewater treatment plant, and from 1949 to 1964 sludges lI'om the treatment plant were di sposed of at the site. Compounds contained in the waste materials li'Dlll Salsbury Laboratories included arsenic, nitrophenol , orthonitroaniline, nitrobenzene, and I, 1,2­trichloroethane. The site was identified as a potential hazardous waste site by the Iowa Department of EnvirolUllental Quality (IDEQ) in 1977. IDEQ studied the site and documented arsenic contamination in surface water associated with the site in reports from 1977 to 1981. The site was placed on the National Priorities List (NPL) in July 1987.

The U.S. Environmental Protection Agency (EPA), in consultation with the Iowa Department of Natural Resources [IDNR (formerly IDEQ)] , issued a Record of Decision (ROD) in September 1991 which presented the remedy for the first operable unit (OU I) as in-situ fixation/stabilization of the chemical fill and surrounding contaminated soil, installation of a low permeability cap, and groundwater monitoring. The ROD also contained a contingency stating that if a treatability study indicated that fixation/stabilization technology was ineffective, the material would be excavated and disposed of at an offsite Resource Conservation and Recovery Act (RCRA) permitted disposa l facility. Treatability study testing conducted subsequent to the signing of the ROD indicated that in-situ fixation/stabilization would not be adequate in treating the chemical lill and surrounding contaminated soil at the site. In 1992 EPA entered into a Consent Decree which would require the city of Charles City, Iowa, and Solvay Animal Health, Inc. , (the successor to Salsbury Laboratories, Inc.) to perform the remedy. An Explanation of Significant Differences (ESD) in March 1992 implemented the contingency remedy of excavation and offsite di sposal at a RCRA-permitted landfill.

In September 2000, the Groundwater OU2 ROD recommended no further action for the groundwater and also that monitoring of the groundwater and institutional controls (ICs) currently placed on the site would be continued under the Consent Decree.

Groundwater is not currently used at or near the site. The city's well s have not been affected by groundwater at the site. ICs prohibit use of or contact with the groundwater. The results of the FYR indicate that the remedy is protective of human health and the environment. Long-IeI'm

ES-I

SHA W AVENUE DUI ....IP SITE SECOND FIVE- YE,\R REVIEW REPORT

protectiveness of the remedial action is verified by quarterly inspections, maintenance, as required , and groundwater monitoring according to thc 2002 revised Site Monitoring and Maintenance Plan.

All immediate threats at the site have been addressed. The remedy for Operable Unit (OU) I (excavation and offsite di sposa l of chemical Ii II and surrounding contaminated soil above hea lth ­based levels); for OU2 (groundwater monitoring and institutional controls); and for the entire s ite is protective of human health and the environment.

ES-2

SHA W AVENUE DUMP SITE SECOND FIVE-YEAR REVIEW REPORT

Five-Year Review Summary Form

SITE IDENTIFICATION

VPost-SARA 0 Pre-SARA 0 NPL-Removal only o NOll-NPL Remedial Action Site 0 NPL State/Tribe-lead o

Triggering action: o Actual RA Onsite Construction at OU # o Actual RA Start o Construct ion Completion V Previous Five-Year Review Report o Other .

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SIIAW t\ VENUE DUMP SITE SECOND FIVE-YEAR REVIEW REPORT

Issues: The fo llowing issues were identitied during the FYR. They are identined in Section 8.0 and in Table I (Recolllmendations and Follow-Up Actions) of the Five-year Review (FYR) Report , and are presented below:

I. Arsenic concentrations have increased in MW-2 s ince 2003. 2. Determine the concentrations of arsenic in sed iment and surface water in the Cedar River

adjacent to the site that can be attributed to increased concentrations in MW-2.

Rccommendations and Follow-up Actions: The site should be maintained by the potentially responsible parties (PRPs) - the c ity of Charles City and rnzer, Inc. (formerly Salsbury Laboratories, Inc. , Solvay Animal Health , Inc. , Fort Dodge Animall-lealth, and Wyeth), and the issue identified above should be addressed in the following manner:

I. Increase the monitoring frequency ofMW-2 n'om biennial to semi-annual to better monitor arsenic concentrations trends.

2 . Obtain sed iment and surface water samples in the Cedar River adjacent to MW-2.

Pl'Otectivcness Statement(s): The remedy lor each of the OUs at the Shaw Avenue Dump Site is protective of human health and the environment. All tlu'eats at the site have been addressed tlu'ough excavation and offsite disJlosal of the chemical nil and surrounding contaminated so il , institutional controls (lCs) that prohibit use of groundwater or intrusive activities, and long-term groundwater monitoring.

Othcl' Comments: Long-term protectiveness of the remedial action has been verified by the fact that the remedy included excavation and offsite di sposa l of the chemical fill and surrounding contaminated soil, and ICs prohibit use of or contact with groundwater at the site.

ES-4

SIIAW 1\ VENUE DlHvlP SITE SECOND FIVE·YEAR REVIEW REPORT

1.0 Introduction

The purpose of the five-year review (FYR) is to evaluate the performance of the remedy and determine whether the remedy remains protective of hl1l11an health and the environment, and functions as intended based on the decision documents. Furthermore, the tive-year review assesses whether the remedy will continue to be protective in the future. It determines whether the exposure assumptions, toxicity data, cleanup levels, and remedial action objectives (RAOs), used at the time of the remedy selection are still valid and whether any other information come to light that could call into question the protectiveness of the remedy.

The United States Environmenta l Protection Agency (EPA) is preparing this FYR pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Section 121(c) and the National Contingency Plan (NCP). CERCLA § 121(c), as amended, states:

({the President selects a rellledial action that res lilts in any hazardolls sllbstances, polilltants, or con/alllin(lIIts re/lwining at the site, the President shall review sllch rellledial action no less olien than each./ive years ((Iier the initiation o./sllch rellledial action to ass lire that hlllllan health and the environlllent are being protected by the rellledial action being illlplelllented. In addition, i/ IIpon sllch review it is thejlldglllent (!{the President that action is appropriate at sllch site in accordance with section [I04j or [I06j, the President shall take or reqllire sllch action. The President shall report to the Congress a list o.l/acilities./iJr which sllch review is reqllired, the res lilts (i/all slIch reviews, alld any actions taken as a reslllt o/slIch reviews.

In the NCP implementing regulations, 40 CFR § 300.430(t)(4)(ii), EPA provided the following interpretation:

(/a rellledial action is .I·elected that reslllts in hazardolls slIbstances, pOlillfal1fS, or col1falllinallts relllaining at the site above levels that allow/or IInlilllited lise and IInrestricted e.lpo.mre, the lead agency shall review sllch acliollllo less often than evelJI./ive years ((Iier the initiation o{the selected rellledial action.

EPA Region 7 has conducted a FYR of the remedial actions implemented at the Shaw Avenue Dump Site in Charles City, Floyd County, Iowa. This review was conducted from January 20 I 0 through March 2010. This report documents the results of that review.

This is the second FYR for the Shaw Avenue Dump Site and covers the period from September 23,2005, through June 24, 2010. The triggering action for this statutory review is the signature date of the previous Five-Year Review Report , which was signed on September 22, 2005. The five-year review is required because hazardous substances, pollutants, or contaminants remain at the site above levels that allow for unlimited use and unrestricted exposure and because the Operable Uni t (OU) 2 ROD was signed in September 2000, after the effective date of the Superfund Amendments and Reauthorization Act (SARA).

SHAW AVENUE I1UMP SITE SECONL> FIVE-YEAR REV IEW REPORT

2.0 Site eh I'ollology

Significant site events and/or milestones for the site are presented in Table 2.

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SHA \V AVENUE DWvlP SITE SECOND FIVE-YE,\R REVIEW RE PORT

3.0 Background

3.1 Physical Chal'acteristics

Thc Shaw Avenue Dump Site is located in Charles City, Floyd County, Iowa (Figul'e 1). The site is within the southeastern part of the city near the intersection of Shaw Avenue and Clark Avenue, adjacent to the Cedar River. The site occupies a portion of the 100-year Iloodplain of the Cedar River.

The drainage area of the Cedar River at Charles City is approximately 1,054 square miles with an average discharge of 650 cubic feet per second, based on measurements obtained at the U.S . Geological Survey (USGS) gauging stations at Charles City. The Cedar River Ilows southeast to a point where it meets the Iowa River, and the Iowa Ri ver continues southeast to ultimately drain into the Mississippi River. Surface water features directly related to the Cedar River in the vicinity of Charles City include oxbow lakes and marshy areas. These features, for the most part, are confined to an area north of Charles City. These features are not prominent at Charles City or just downstream of Charles City. This, along with the presence of rapids in the Cedar River within the city limits, may indicate that the Cedar River, south of the meander features, is flowing through a bedrock-controlled valley. Surface water features partially related to the Cedar River are the water-filled depressions found sporadically within the floodplain of the river. The Cedar River is probably the source of recharge to these features.

The site and surrounding area generally slope from the northeast to the south and southwest, including a high area at the northeast and a low point at the south/southwest perimeter of the site. The northeastern elevation is approximately 1,020 feet above mean sea level (AMSL), and the south/southwestern elevation is approximately 980 feet AMSL.

The Charles City area lies near a junction of two types of slightly di fferent continental climates. These are humid cold and moderate winter type climates. The actual area lies just inside the humid cold winter region.

3.2 Land and Resoul'ce Usc

The Shaw Avenue Dump Site is owned by the city of Charles City. The site runs parallel to and is bounded to the west by the former location of the Iowa Terminal Railroad tracks (now a walking path) to a point where the tracks turn west and cross the Cedar River. The city of Charles City stockpiles mulch along the entrance road near the wastewater treatment plant for use by local residents. The city also constructed an asphalt pad near the wastewater treatment plant to provide a dry place for residents to pick up the stockpiled mulch. A chain-link fence borders the site to the north and east, and the site is bordered by the Cedar River and tree line to the south. Major cultural features are identified on Figul'e 2.

The ecological resources in the Charles City area are oriented around the Cedar River. The river serves as a source of replenishment for the water-bearing zones in its vicinity. The Cedar Ri vel'

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downstream of the Shaw Avenue Dump Site is used as a source of contact and non-contact recreation.

The population of Charles City, Iowa, is 7,812 according to the 2000 census. The major uses of the land in the general vicinity of Charles City are: farmland, including crops and orchard operations; livestock grazing; industry; urban; and sand pit and quarrying operations.

3.3 History of Contamination

The city of Charles City purchased the northern area of the site in 1899 and continued to acquire additional sections of it until 1964. A municipal landfill was operated at the site prior to 1949 until 1964. The site was used by Salsbury Laboratories, Inc. (later Solvay Animal Health, Inc.) from 1949 to 1953 to dispose of chemical waste generated by chemical batch processing of arsenic compounds used in Salsbury's production of animal pharmaceuticals. Sludges from the Charles City wastewater treatment plant were disposed of at the site Ii'om 1949 to 1964, and the city received liquid industrial waste fi'om Salsbury during this same period. Salsbury's liquid waste during this period included arsenic, nitrophenol, orthonitroaniline, nitrobenzene, and I, I ,2­trichloroethane (1,1,2-TCA). The quantity of chemical waste disposed of by Salsbury at the site is estimated to be between 14,000 and 28,000 cubic feet; and the quantity of solid waste disposed of at the site li'om the city's treatment plant from 1949 to 1964 is estimated to be 10,000 tons.

The chemical fill which was excavated as part of the remedial action was located in the alluvium that overlies the Upper Cedar Valley limestone formation. The Upper Cedar Valley limestone formation is a fractured, weathered limestone layer which is hydrologically separated ti'om the Lower Cedar Valley limestone formation by a relatively impermeable shale, the Chickasaw Shale. The Chickasaw Shale acts as a confining unit, preventing flow from the upper to the lower unit. An upward hydraulic head also prevents flow from the upper to the lower unit. An unconfined alluvial aquifer occupies the southern portion of the site near the Cedar River and a local perched aquifer at the northern end of the site. Groundwater in the Upper Cedar Valley aquifer typically flows west to southwest along the northern and southwestern portions of the site, and flows south in the southeastern portion of the site to the Cedar River. The general groundwater flow direction is shown on Figure 3. This interpretation is based on water levels collected from all site wells during October, 2009 and is consistent with historical ground water now maps.

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SHAW AVENUE I..) U~\'1J> SITE SECOND FIVE· YEAR REVIEW REPORT

3.4 Initial Response

In 1977 the Iowa Department of Environmental Quality (IDEQ) identified the site as a potential hazardous waste site. IDEQ documented arsenic contamination in surlace water in an abandoned grave l pit near the site in reports between 1977 and 1981. A Preliminary Assessment was conducted in 1984. The site was proposed for the NPL in 1985 and was li sted in 1987.

The remedial investigation (RI) was initiated in 1988 and completed in 1990. The naturc and extent of contamination was estimated during the RI by analyzing samples from the chemical fill , soil borings, and groundwater monitoring wells. An inventory of private wells was conducted for a di stance of one-half mile around the site by the city of Charles City. All residences within the city limits of Charles City are on the city water supply. Electromagnetic and seismic refraction surveys were conducted as part of the RI in 1988. The electromagnetic survey was successful in identifying differences in fill material characteristics and identifying highly conductive materials and metallic objects. The seismic reli'action survey determined the approximate depth to the top of the bedrock across the site, and the data interpretation aided in finalizing monitoring well locations, which was subsequently verified during drilling activities at the site. Chemical fill was identified in t1U'ee waste ce ll s around a city-owned maintenance facility located in the northern portion of the site. The chemical fill was located approximately two to three feet below the ground surface and extended vertically to bedrock. The thickness of the chemical fill encountered ranged from 0.5 feet to 9.5 feet. The total volume of chemical till was calculated to be 370 cubic yards with additional contamination in the adjacent soil. The chemical fill exhibited characterist ics of process wastes generated by Salsbury Laboratories, Inc. , from 1949 to 1953. Analyses of samples collected from the chemical till during the RJ showed high levels of arsenic, cadmium, chromium, lead, volatile organic compounds (VOCs), and semi­volatile organic compounds, including methylene chloride, I, 1,2-TCA, and orthonitroaniline. A 200-gallon underground gasoline storage tank was located in the vicinity of the chemical fill. The tank was owned by the city, used as a fuel source for city vehicles, and was a source of benzene, toluene, xylene, and manganese in soil and groundwater.

The Phase I RI included collection and compositing of 45 surface soi I samples from predetermined grid intervals from four individual areas over the site, collection of subsurface borehole soi l samples during monitoring well drilling, and completion of three alluviumll1l1 borings (BH5a, BH5b, and BH5c) onsite. The Phase 2 RI expanded the investigation to include completion of 90 alluvium/fill borings (BH6 through BH95) and three excavation test pits (TP-l , TP-2, and TP-3) which were completed in an effort to locate waste di sposa l cells. Surface and subsurface soil samples were found to contain polycyclic aromatic hydrocarbons (PAHs) and heavy metal s including arsenic, beryllium, cadmium, and lead.

Several hydraulically-separated water-bearing units characterize the site. A local perched aquifer exists in the northern region of the site. The chemical fill was located in the unconfined alluvium overlying the Upper Cedar Valley limestone formation. The Upper Cedar Valley fractured limestone is separated !l'om the Lower Cedar Valley limestone by the relatively impermeable Chickasaw Shale unit. An upward hydraulic head prevents the flow of groundwater from the Upper Cedar Valley aquifer to the Lower Cedar Valley aquifer.

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SHI\W 1\ VENUE l)Uf\'lP SITE SECOND FIVE·YEAR REVIEW REPORT

Dming the Phase I RI, 15 groundwater monitoring well (MW) nests werc installed; eight alluvium wells (MW-IA, MW-I B, MW-2A, MW-3A, MW-4A, MW-4B, MW-6A, and MW-8A); and seven upper bedrock wells (MW-2, MW-3, MW-4, MW-6, MW-7, MW-8, and MW-9) on and in the vicinity orthe site. The Phase 2 RI activities included installation of four additional alluvium wells (MW-12/\, MW-15A, MW-15B, and MW-18A) and 10 upper bedrock wells (MW-I, MW-IO, MW-II , MW-12, MW-13, MW-14, MW-15, MW-16, MW-17, and MW-18).

VOCs including vinyl chloride, I, I-dichloroethene, I ,2-dichloroethane (I ,2-DCA), and I, I ,2-TCA were detected in groundwater monitoring wells in the southern portion of the site, and arsenic was detected in the northern and central portions of the site. Benzene, toluene, and xylene were detected in the northern portions of the site. Monitoring well locations are shown on Figures 2 and 3. Monitoring well construction details are included as Table 3.

Two di screte surface water grab samples were collected dming the Phase I RI at station I I (upstream) and station 12 (downstream) from the Cedar River. Samples were collected for arsenic, orthonitroaniline, and 1, 1,2-TCA analyses.

A second RI began in 1992 for the second OU, the groundwater OU (OU2), and was completed in 1999. Monitoring well MW-19 was installed dming this time period (following the February 1994, Potentially Responsible Party (PRP)-Ied, ~UI remedial action which removed all chemical till and surrounding soil contaminated above health-based levels) as a deep well pair for MW-8. Quarterly groundwater monitoring was conducted during the OU2 RI for vinyl chloride, I, I -dichloroethene, 1,2-DCA, 1,1,2-TCA, benzene, toluene, xylene, 2-nitroaniline, arsenic, cadmium, and manganese. Two private wells formerly located within the vicinity orthe site, were abandoned according to lDNR regulations in 1997 aner the homes were provided with municipal water by the city of Charles City. The Charles City municipal water supply wells have not been affected by site contaminants. Groundwater is currently not used at or near the site.

3.5 Basis for TaIling Action

Chemical fill was identified at the site during the RI through the installation of 93 exploratory boreholes and three test pits. In February 1992 an additional 37 boreholes were completed at the site to further detine the extent of the chemical fill and contaminated soil. Based on data from the borings and test pits, the extent of chemicallill was delineated. The chemicallill was located approximately two to three feet below ground surface and generally extended vertically to the top of bedrock. The thickness of the chemical till encountered ranged lI'om 0.5 to 9.5 feet.

The chemical till identified onsite was characterized by the presence of arsenic (up to 50,000 milligrams per kilogram [mg/kg]) and orthonitroaniline (up to 95,000 mg/kg), and to a lesser extent by relatively low concentrations of various halogenated organic compounds (less than I mg/kg) , aromatic hydrocarbons (less than I mg/kg), and various metals. The chemicallill was the source of the arsenic and orthonitroaniline in the groundwater. The 200-gallon underground gasoline tank , located in the vicinity of the chemical fill which was removed and disJlosed of

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SH/\W /\VENUE DUMP SITE SECOND FIVE· YEAR REVIEW REPORT

ofTsite as a part of the OUI remedial action in 1994, was considered a poss ible source of benzene, toluene, xylene, and manganese in so il and groundwater. The tank was scraped to remove any remaining soil on the exterior, carbon monoxide was added to lower the explosive level , and the tank was disposed of as scrap metal by the PRP. Sampling around the underground storage tank was conducted in accordance with the state of Iowa and federal underground storage tank regulations. As part of the chemical till and so il excavation activities, all soils beneath and within three feet of the tank were excavated to the top of bedrock and wcre disposed of offsite at a chemical waste management authorized Resource Conservation and Recovery Act (RCRA) landtill. Conlinnation and verification soil samples were collected during excavation activities according to the protocols presented in the lield sampling plan. Conlinnation soil sampling was conducted to determine if the performance standard of 50 parts per million (ppm) for total arsenic had been met. An approximate total volume of2,220 cubic yards of chemical fill and contaminated so il was excavated and disposed of ol'i'Site at an authorized RCRA landfill according to the March 1992, EPA-approved Remedial Design submittcd by the PRP.

A baseline risk assessment was conducted to evaluate the potential impacts to human health and the environment posed by site contaminants. Both current and future land use scenarios were evaluated. An ecological assessment was also performed as a companion to the baseline human health risk assessment. The ri sk assessment consisted of an identilication of chemicals of potential concern, an exposure assessment, a toxicity assessment, and a risk characterization.

Contaminants of concern are contaminants that have been detected at the Shaw Avenue Dump Site, have inherent toxic or carcinogenic effects, and are likely to pose an unacceptable risk with respect to the protection of human health and the envirolUnent. Forty individual compounds, in addition to a group of similar PAl-Is, were identilied as potential chemicals of concern in the soil, surtace water, groundwater, and chemical fill at the site.

The exposure assessment identilied potential pathways and routes for contaminants of concern to reach the receptors, and the estimated contaminant concentration at the points of exposure. The toxicity assessment characterized available human health and environmental criteria for the contaminants of concern, and qualitatively-related potential chemical exposure to expected adverse health effects. The risk characterization quantifies present andlor potential future risks to human health that may result from exposure to the contaminants of concern found at the site . For carcinogens or suspected carcinogens, a quantitative risk assessment involves calculating risk levels considered to represent the probability or range of probabilities of developing additional incidences of cancer under the prescribed exposure conditions. A lifetime cancer ri sk of I x 10-6 indicates that an individual has a one in one million chance of developing cancer as a result of s ite-related exposure to a carcinogen over a 70-year lifetime, under the specific

6exposure conditions at a site. The acceptable risk range is within a range of 10-4 to 10. The carcinogenic risk assessment for the site indicated that under reasonable maximum exposure scenarios, cancer risks for future residential use range from I x 10-3 to 6 X 10-2 (one additional person out of a thousand to six additional persons out of a hundred are at risk of developing cancer).

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SHA W AVENUE OlJrvlP SITE SECOND FIVE-YEAR REVIEW REPORT

Reference doses have been developed for indicating the potential for adverse health effects from exposure to chemicals exhibiting non-carcinogenic effects. Potential concel'll for non­carcinogenic effects of a single contaminant in a single medium is expressed as the hazard quotient (or the ratio of the estimated intake derived It'om the contaminant concentration in a given medium to the contaminant's reference dose) . By adding the hazard quotients for all contaminants within a medium or across all media to which a given population may reasonably be exposed, the hazard index can be generated. Hazard indices greater than one are associated with potentially increased health risks. Hazard indices for this site ranged from less than one to 185.

Based on the results of the ri sk assessment, it was determined that actual or threatened releases of hazardous substances from this site, ifnot remediated , may present an imminent or substantial endangerment to public health , welfare, or the environment.

A risk assessment addendum completed in 1998 for OU2 indicated that cancer risks for future residential use of the site, including an onsite drinking water well, would range from 3.6x 10'4 to 6.2 x 10'4 (four to six additional persons out often thousand at risk of developing cancer). The hazard indices for non-carcinogenic exposure were less than one except for a tilture onsite resident in contact with groundwater, which would be prohibited because the site restrictive covenant does not allow installing a groundwater well onsite. The risk is within the acceptable range for OU2, except future residential exposure, which is controlled by the site ICs.

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4.0 Remedial Actions

4.1 Remedy Selection

The ROD for OU I was signed on September 26, 1991. The remedy selected included in situ fixation/stabilization and capping of contaminated soils and chemical till, along with groundwater monitoring. The remedy also included ICs requiring the city of Charles City, the owner ofthe site, and Solvay Animal Health, Inc., the successor to Salsbury Laboratories, Inc., to submit the IC document for recording by the Floyd County Recorder. The restrictive covenant which runs with the property states that " the construction, installation, maintenance, or use of any well s on the property for the purposes of extract ing water tor human drinking, bathing or swimming purposes or tor the irrigation of food or feed crops as well as any construction or intrusive activities on this property is prohibited." In addition, a perpetual and permanent easement to enter upon the property is granted and conveyed for the purpose of conducting tests, performing remedial measures, and periorming operation and maintenance (O&M) activities. A security fence and warning markers were installed outside the boundaries of the capped area to prevent unauthori zed entry. Groundwater monitoring was conducted to assess the effectiveness of the remedy in preventing migration of contaminants.

Treatability testing, conducted subsequent to the signing of the OU I ROD and reviewed by EPA, indicated that in situ fixation/stabilization was not adequate in treating the chemical till and surrounding contaminated soil. An Explanation of Significant Differences (ESD), signed on March 20, 1992, modi tied the OU I remedy from in situ fixation/stabilization of contaminated soi ls and cappi ng of the chemical fill to excavation and offsite disposal or the chemical nil and surrounding contaminated soil at a RCRA-permitted landfill. The RAOs tor OU I were to eliminate or reduce to an acceptable level the risks posed by exposure to the contaminated soil and chemical fill, and to eliminate or reduce the potential migration of contaminants into the groundwater. These were accomplished through the removal, stabilization, and off-site disposal of all chemical waste and contaminated soil above health-based levels from the site ; groundwater monitoring; and the imposition of lCs to prohibit certain ki nds of development and uses on the site.

A second ROD was signed on September 28,2000, for OU2, the groundwater OU. The RAOs of the OU2 ROD were continuation of groundwater monitoring and ICs currently in place at the site.

4.2 Remedy Implementation

On May 26, 1992, EPA entered into a Consent Decree, Civil Action No. C92-2026, with the city of Charles City, Iowa, and Solvay Animal Health, Inc., the successor to Salsbury Laboratories, Inc. The Consent Decree required the city of Charles City and Solvay Animall-Iealth, Inc. (later Fort Dodge Animal Health, Wyeth, and Pfizer as of October 2009) to perform excavation and disposal of the chemical fill and contaminated soil , to conduct the groundwater monitoring, and to implement ICs, which includes the restrictive covenant and easement on the site property.

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The OU I remedial design was approved by EPA in March 1992 and the remedial action completed in February 1994. Thc remedial action activities for OU I included excavation and offsite disposal orthe chemical 1111 and surrounding contaminated soil along with verification testing to assure that the performance standards were met; the excavation and offsite disposal of a 200-gallon underground gasoline storage tank; backlliling with sand and top soil; and site grading and seeding. Excavation of the chemical fill and contaminated soil was conducted to bedrock in all areas that were determined to be contaminated above the performance standards.

4.3 System Operation/Operation and Maintenance

The O&M phase of the remedial action began in March 1993 , one year from the onsite remedial action start date, and consists of quarterly inspections and reporting on site conditions, and monitoring and evaluation of groundwater and surface water data. O&M procedures have been properly implemented and are being sufficiently maintained to assess the effectiveness of the remedial action and to ensure current and long-term protectiveness of the remedy.

To implement the ICs required by the Consent Decree, the EnvirolUnental Protection Declaration of Restrictive Covenants and Easements was completed on Febl'llary 21 , 200 I, by and between the city of Charles City, Iowa, 105 Milwaukee Mall, Charles City, Iowa, and Fort Dodge Animal Health,S Giralda Farms, Madison, New Jersey.

The potentially responsible parties (PRPs) - the city of Charles City and Pfizer, Inc . (formerly Salsbury Laboratories, Inc., Solvay Animal Health, Inc., Fort Dodge Animal Health, and Wyeth) continue to submit groundwater monitoring reports and maintain the site according to the Consent Decree.

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5.0 Progress Since Last Review

The protectiveness statement in the nrst FYR (EPA, 2005) concluded that the remedy of excavation, treatment and disposal of contaminated materials at an offsite RCRA-permitted landfill was protective oflullllan health and the environment. No signiticant issues were identified during the first FYR regarding the site conditions or the groundwater monitoring wells. No denciencies were observed and, therefore, no follow-up actions were deemed necessary.

The protectiveness statement provided in the nrst FYR is as follows :

"The results of the five-year revie\v indicate that the remedy is protective or human health and the environment. The remedy of excavation with hydraulic excavator and treatment and disposal at an offsite RCRA permitted landfill and groundwater monitoring has been shown to be effective."

O&M activities are ongoing according to the OU2 ROD and consist of quarterly inspections and reporting on site conditions, and monitoring and evaluation of groundwater. Surface water data are evaluated in conjunction with the LaBounty Site, located immediately adjacent to the Shaw Avenue Dump Site, on the west bank of the Cedar River, as contributions of arsenic ti'om the Shaw Avenue Dump Site are thought to be minor in comparison. Stations II and 12 are sampled quarterly and the McDonnell Station is sampled monthly. There have been no exceedances of the action levels established by EPA and IDNR for any Cedar River monitoring point during the FYR period.

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6.0 Five-Yea I' Review Pl'ocess

6.1 Administrative Components

The Shaw Avenue Dump Site FYR included the following team members: Shelley Brodie, EPA Region 7 Remedial Project Manager (RPM); Fritz Hirter, EPA Region 7 Community Involvement Coordinator; and Dave Daniel, Risk Assessor, Andy Gosnell, Geologist, and Fred Molloy, Technical Lead, U.S. Army Corps of Engineers, Kansas City District (CENWK). Robert Drustrup, IDNR Environmental Engineer, Tom Brownlow, City Administrator, Charles City, and Tracy Meise, Planning and Project Supervisor, Charles City were notilied of the FYR and FYR site inspection on January 21, 2010.

6.2 Comlllunity Involvement

A public notice regarding initiation of the five-year review was placed in the Charles City Press on March 10,20 I 0; and at the end of the five-year review, a newspaper notice will indicate the availability of the five-year review report for viewing by the public. The completed live-year review report will be available in the site information repository, the Charles City Public Library, 106 Milwaukee, Charles City, Towa 50616; the EPA Superfund Division Records Center, 90 I North 5th Street, Kansas City, Kansas 66101; and the IDNR offices, Wallace State Oftice Building, 502 E. 9th Street, Des Moines , Iowa 50319.

6.3 Document Review

This FYR included a review of relevant information contained in a variety of site-related documents, including an assessment of the condition of the administrative record located at the Charles City Public Library. The information review primarily focused on documents produced after September 2005 (start of the FYR time frame), but also included information presented in the FS Addendum, ESD, OU2 ROD, PCOR, the First Five-Year Review Report , boring logs, well construction details, and quarterly inspection and monitoring reports. A list of site-related documents, reviewed in total or in part during preparation of this FYR, is contained in Attachment 4.

6.4 Data Review

During the first FYR period, groundwater monitoring was performed quarterly according to the Consent Decree. Tn 2002 EPA and IDNR approved the Proposed Groundwater Monitoring Program and the frequency of groundwater monitoring was revised to a semi-aIUlual schedule for bedrock monitoring wells (MW-6, MW-7, and MW-8) and to a biennial schedule for all other wells . During the second FYR period, groundwater monitoring continued according to this revised schedule; semiannually for bedrock monitoring wells MW-6, MW-7, and MW-8; and biennially for all other wells. Groundwater monitoring was used to assess the effectiveness of the remedy in preventing the migration of contaminants. Monitoring program requirements are summarized in Table 4.

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During this FYR period annual reports were submitted by the PRPs sumnJarizing groundwater monitoring results and maintenance activities. Groundwater monitoring data were consolidated tium the annual PRP reports and included in this report as Tables 5 through 7. Table 5 is a compilation of measured groundwater levels over the review period; Table 6 presents analytical results over the FYR review period; and Table 7 is a compilation of precipitation data for the Charles City area over the FYR review period. Under the current Consent Decree, surface water sampling is not conducted in association with the Shaw Avenue Dump Site, but continues at the LaBounty Site, located immediately adjacent to the site on the west bank of the Cedar River.

As shown in the attached tables and tigures, MW-2, MW-6, MW-7, and MW-8 contain the highest concentrations of arsenic . MW-8 is adjacent to the fonner extent of chemical fill and MW-7 is located along Shaw Avenue, between the former chemical till area and the Charles City wastewater treatment facility. MW-6 is southwest of the fonner fill area, in the downgradient direction MW-2 is located downgradient ofMW-6, immediately adjacent to the Cedar River (Figure 3).

6.5 Evaluation of Historical COC Concentration Trends

As previously stated, MW-2, MW-6, MW-7, and M W -8 contain the highest concentrations of arsenic . Of these three wells, MW-6 and MW-8 are located adjacent to or immediately downgradien( of the fonner chemical till area . MW-7 is located down and side-gradient of former chemical fill area. During the FYR period, sampling results have shown decreasing trends in arsenic concentrations in MW-6 and MW-8. Trend plots for these wells were constructed using simple lineal' regressions and are included as Figures 5 and 7. The plots show a consistent decline in arsenic concentrations since 2002. The arsenic concentration in MW-6 has consistently declined from 1,400 micrograms per liter (~lg/L) in April 2003 to approximately 170 ~lg/L in October 2009. Arsenic concentrations in MW-8 decreased steadily from 9,500 pg/L in 2003 to approximately I ,000 ~lg/L in 2009.

The concentrations of arsenic in MW-7 remain relatively stable. No di scernable trend was evident, based upon data collected following OU2 remedy implementation (Figure 6). Arsenic concentrations in this well vary, but are generally about 120 ~lg/L. Another side-gradient well , MW-II, shows similar concentrations over time, with no discernable trends (Table 6). It is theorized by the PRP contractor that the concentration tluctuations in these two wells are due to short-lived groundwater gradient changes caused by isolated precipitation events. This could account for the spikes and drops of arsenic concentrations over time since source removal.

An apparent upward trend was observed in MW-2 (Figure 4). During this FYR period this well was sampled biennially; therefore, it was only sampled three times since approval of the revised monitoring plan. During this period (2004 to present), arsenic concentrations increased from 162 ~lg/L to 954 ~lg/L. Based on this observation CENWK provided a recommendation to the EPA RPM that the sampling ti'equency be increased from biennial to semi-annual. This recommendation was provided to the PRP and implemented during the April 20 I 0 sampling event. Sampling ofMW-2 will continue on a semi-alUlllal basis.

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MW-2 is located in the downgradient direction from the MW-6/MW-6A well cluster. MW-6, which is screened in bedrock, is current ly impacted with arsenic. Historical concentrations in the associated alluvial well (MW-6A) were generally below action levels. This situation is mirrored in the MW-2/MW-2A cluster. Thc alluvial well (MW-2A) at this location has not shown arsenic concentrations in excess of the act ion level since 1997, and was last sampled in 2002. MW-2 is screened in bedrock, indicating that arsenic present in this well could be emanating from the fonner chemical Ii II area, which impacted M W -6. The presence of arsenic in MW-2 indicates bedrock plume migration in the down-gradient direction.

No other COCs were detected in excess of cleanup goals during the review period.

6.6 Site Inspection

A March 10,2010, site inspection was conducted by Shelley Brodie, EPA, supported by Andy Gosnell and Fred Molloy, CENWK; Tom Brownlow and Tracy Meise, the ci ty of Charles City; and Neil Leipzig, the PRP contractor, Conestoga-Rovers & Associates. Robert Drustrup and Cal Lundberg, IDNR, were unable to attend.

The purpose of the site inspection was to assess the condition of the remedy and identify any issues that could negatively affect the protectiveness of the remedy. The site inspection assessed the overall maintenance of the site, the sl\l'face integrity of the groundwater monitoring wells (including, well pads, protective covers, stickup, name plates, and locks), perimeter fencing, and ICs which prohibit the construction of wells for any purpose at residences, including irrigation.

Prior to the site inspection, the inspection team met for introductions and to discuss the itinerary. The meeting was conducted in a conference room at the Sleep Iml & Suites, 1416 South Grand Avenue, in Charles City. Interviews were also conducted during the meeting and are discussed in Section 6.7 below.

The site inspection began by driving to the intersection of Clark Street and Shaw Avenue, which is the site of the entrance to the fenced area of the Shaw Avenue site . The inspection team was led by Neil Leipzig who has been an investigator of the site for the PRPs and is currentl y the PRP contractor project manager.

MW-S, MW-SA, and MW-19 (Photo No.1) were observed on the north side of the entrance road to the site. The remediated waste excavation area , the fonner chemical fill area, included a grass covered area between MW-8 and MW-SA and the road. It was noted that, although secl\l'ely locked, the well cap for MW-SA could be opened without removing the lock. The inspection team then proceeded south toward the city wastewater treatment plant on the southern edge of the property, observing MW-7 and MW-IO (I)hoto No.2) and on through an unlocked gate along a gravel and dirt road toward the Cedar River. Mounds of mulch (Photo No.3) and concrete debris (Photo No.5) lined the road. Large mounds of mulch were present on the south side of the road adjacent to an asphalt pad which was constructed to allow residents a dry place to pick up mulch and drop off debris. The city of Charles City allows access to this area for disposal of Christmas trees and concrete debris and provides the mulch to the local residents.

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The team then walked to MW-IS, MW-ISA, and MW-1SB (Photo No.4), which were observed along the road in a low-lying, partially-wooded area between mounds of mulch and concrete debris. The team proceeded toward gauging station 12 (Photo No.6) adjacent to the Cedar River in the I DO-year floodplain. The team proceeded to MW-3 and MW-3A crossing a road on top of a dike constructed after the 2008 flood to protect the city' s wastewater treatment plant lift station 6'om flooding.

The team returned to the vehicles and drove to the north side of the site tlu'Ough the entrance to the R Campground. MW-6 and MW-6A were observed on the south side of the road and further south the team observed flush-mounted wells MW-4, MW-4A, and MW-4B. It was noted that MW-4 was miss ing a mechanical well plug/cap and at MW-4B the concrete well pad lacked sufficient slope to discourage entry of surface-water I'lmoff and was cracked around the edges possibly from vehicular traffic (Photo No.7). The team proceeded on foot around the southern perimeter of the campground, adjacent to a pond, and observed flush-mounted wells MW-2 and MW-2A within the flood plain of the Cedar River. It was noted that MW-2 did not have a mechanical well plug/cap to discourage entry of surface-water runoff.

The team proceeded to the north end of the property to MW-13, M W -14, and MW-17. Although the well caps were secured by locks, MW-14 and MW-17 did not have mechanical well plugs/caps. In addition, the PRP's contractor stated that MW-14 was obstructed and could no longer be used for water-level collection.

The PRP's contractor pointed out that MW-13 had a different style lock on it to discourage vandalism. I-Ie noted instances where the previous locks had been cut off and the well purportedly used by parties investigating contamination associated with petroleum storage tanks at the gas station formerly located near the intersection of Shaw Avenue and Clark Street. When the well cap was removed a bailer, not used for sampling by the PRP's contractor, was tound inside the well.

Flush-mounted wells MW-18 and MW-18A were observed on the north side of Clark Street , prior to leaving the site. It was noted that one of the bolts securing the well cap was miss ing from MW-18. The second remaining bolt was loose allowing the lid to be pried ofr. It was also pointed out that MW-IS was obstructed, preventing water-level collection at this location.

The list of maintenance items identitied above has been provided to the PRP's contractor for follow-up. Table 15 provides the identified maintenance items and their implementation status. The former chemical till area has been excavated and remediated and is currently grass covered. The groundwater monitoring well s are intact. The area is pattially fenced; however, the access gate is left open to provide public access to the mulch and for di sposal of concrete debris. The city indicated that they were not aware of any di sturbance or vandalism of site property or monitoring wells.

There have been no changes in land use in the surrounding area s ince implementation of the ROD. The site is bounded by residential areas across Clark Street to the north, east, and

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51 IA W AVE NUE Dur"IP SITE SECOND FIVE· YEAR REVIEW REPORT

northwest and by the Cedar River to the west and southwest. The city wastewater treatment plant is locatcd southeast of the former chemical fill area.

6.7 Inte..views

Interviews were conducted at the Sleep Inn & Suites at 1416 South Grand Avenue in Charles City. The following individuals were interviewed on March 10,20 I0: Shelley Brodie, EPA; Tom Brownlow, the city of Charles City; Tracy Meise, the city of Charles City; and Neil Leipzig, Conestoga-Rovers & Associates . Robert Drustrup and Cal Lundberg, IDNR, were unable to participate in the interviews on March 10,20 I 0, but were interviewed on March II, 2010, at the same location.

All interviewees stated that they had been well informed about the site's activities and progress, and that they had no concerns regarding the protectiveness of the site. Neil Leipzig, Conestoga­Rovers & Associates, indicated that the remedy was functioning as expected and, based on data obtained from MW-6 and MW-8, contaminant levels were decreasing ncar the former source.

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7.0 Technical Assessment

As identi fied in Section 1.0, the type of review is considered to be a statutory review. According to EPA 's Comprehensive Five-Year Review Guidance (EPA, 2001), a statutory review is conducted when (1) upon completion of the remedial action, hazardous substances, pollutants, or contaminants will remain on site; and (2) the ROD for the site was signed on or after October 17, 1986, (the effective date of SARA) and the remedial action was selected under CERCLA § 121. The remedial action for OU2meets these criteria. EPA guidance also identifies the trigger for statutory review as the signature date of the previous FYR Report, which was signed on September 22,2005. This document constitutes the FYR for the entire site.

This section presents a technical assessment and is formulated based on the answers to Questions A, B, and C, presented below. As answers were formulated, consideration was given to the status of the remedial action. For consistency with FYR guidance, each question is summarily answered yes or no. Supporting information is provided in the previous sections and referenced documents with additional analysis provided, as needed. Section 7.4 presents a summary of the technical assessment.

Questioll A: Is the remedy functioning as intended by the decision documents?

Questioll B: Are the exposure assumptions, toxicity data, cleanup levels, and remedial action objectives (RAOs) used at the time of the remedy selection still valid?

Qllestioll C: Has any other information come to light that could call into question the protectiveness of the remedy?

7.1 Question A: Is the remedy functioning as intended by the decision documents?

Yes.

7.1.1 Remcdial Actionl'crfol'lllance

The remedy has been shown to be effective in meeting the RAOs which are eliminating or reducing to an acceptable level the risks posed by exposure to the contaminated soil and chemical fill, and eliminating 01' reducing the potential migration of contaminants into the groundwater. This was accomplished through the removal , stabilization, and off-site disposal of all chemical waste and contaminated soil above health-based levels fi'Om the site; groundwater monitoring; and the imposition of ICs to prohibit certain kinds of development and uses on the site

A review of available documents, ARARs, risk assumptions, and the results of the site inspection indicate that the remedy of excavation, treatment, and disposal at an offsite RCRA-pel'll1itted landfill , which was selected in the ESD, and the groundwater monitoring selected in the OU2 ROD was appropriate. Groundwater monitoring has continued as specified in the revised

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monitoring plan, and monitoring in the Cedar River has continued in conjunction with the LaBounty Site Order on Consent.

7.1.2 System Opel'atiolls/O&M

The PRPs (the city of Charles City and Pfizer, Inc.) continue to monitor the effectiveness orthe remedial action at reducing concentrations of contaminants in the groundwater, and preventing the migration of contaminants. This is accomplished by performing groundwater monitoring, submitting monitoring reports, and maintaining the site according to the Consent Decree. Dming this FYR period, groundwater monitoring continued according to the schedule established in the Groundwater Monitoring Program which was approved by the state of Iowa in May 2002. Results from the monitoring program for the FYR period are presented in Table 6. Monitoring wells are maintained by the PRP's contractor.

Currently, groundwater is monitored at select site wells following the approved schedule presented in Table 4. However, all site wells are used to assess groundwater flow on a quarterly basis. One well, MW-14, is obstructed and calmot be used for water level collection. Consideration should be given to abandoning rather than replacing thi s well since it is currently not part of the monitoring network, sufficient control exists to assess futme groundwater flow, and the site conceptual model is well developed. CENWK provided a recommendation to the EP A RPM that MW-14 be visually inspected with a down-hole camera to determine the nature of the obstruction. This recommendation was provided to the PRP and implemented in May 2010.

In August 2009 several wells located on the campground property were converted from "stick­up" type completions to mounts flush with the ground surface. For sampling and water-level measurements, they are accessed via a small manhole. These wells include MW-2, MW-2A, MW-4, MW-4A, MW-4B, and MW-14. They were not smveyed at the time of the March 10, 20 I 0, site inspection, but the PRP contractor indicated that this would be accomplished in the spring of2010. Several of these wells are missing mechanical well plugs/caps that would prevent infiltration of smface water into the well dming flooding events. Fmthermore, the integrity of several of the concrete pads smrounding the manholes was questionable. These issues were brought to the attention of the PRP contractor dming the site inspection, who indicated that an inventory of all flush-mount well installations would be conducted and repairs made, as necessary.

It was brought to the attention of the FYR inspection team that MW-13 was accessed, without permission, by an adjacent property owner, purportedly to sample for fuel constituents associated with leaky petroleum storage tanks at a former service station located near the intersection of Shaw Avenue and Clark Street. The lock on this well was replaced with a tamper-proof-type lock and no subsequent vandalism has occurred. The PRP contractor also indicated that cave-ins were evident in open-borehole monitoring well MW-18 that prevented water-level collection. CENWK provided a recommendation to the EPA RPM that MW-18 be vi sually inspected with a down-hole camera to determine the natme of the obstruction. This recommendation was provided to the PRP and implemented in May 20 I O.

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Water level s in site alluvial and bedrock monitoring wells over the course of the review period were plotted against precipitation events. These plots are included as Figures 8 and 9. There was good correlation between water levels and precipitation events, and no notable issues were identified.

7.1.3 Opportunities for Optimization

No opportunities were identified to improve system performance. However, opportunities to reduce costs associated with monitoring and sampling may exist. A reduced sampling frequency for certain groundwater monitoring wells should be explored. Requests for optimization (revised sampling and analysis schedule, among others) should include the basis for the request and sufficient documentation to support the request and ensure the protectiveness of the remedy.

7.1.4 Early Indicators of Potential Issues

Continued evaluation of groundwater monitoring is essential to evaluate the current upward trend of arsenic in MW-2. If the upward trend continues or impacts the adjacent Cedar River, further investigation will be warranted.

7.1.5 Implementation oflnstitutional Controls and Other Measures

The city of Charles City maintains ownership of the property which comprises the site, and there are no current or plaIUled changes in land use. The site is listed on the State Registry of Hazardous Substance or Hazardous Waste Disposal Sites pursuant to Iowa Code 4558.426. The state registry listing, which is filed with the county recorder, prohibits the sa le or significant change in use of the property without the written approval of the Director of IDNR. A restrictive covenant was recorded with the Floyd County Recorder that satislles the IC provision of the ROD and Consent Decree for the Shaw Avenue Dump Site. The restrictive covenant runs with the property comprising the site and prohibits the construction, installation, maintenance, or use of any wells on the site for purposes of extracting water for human consumption, bathing, or swimming, or for the irrigation of food or feed crops, as well as any construction or intrusive activities at the site. The city also submitted for recording with the Recorder of Deeds, access easements which run with the property comprising the site and which reserve such access as may be necessary for the PRPs to implement any future remedial action and for conducting O&M of the remedy. The Environmental Protection Declaration of Restrictive Covenants and Easements was completed on February 21, 2001, by and between the city of Charles City, Iowa, 105 Milwaukee Mall , Charles City, Iowa, and Fort Dodge Animal Health, a division of American Home Products, 5 Giralda Farms, Madison, New Jersey.

7.2 Qucstion B: Arc the exposure assumptions, toxicity data, cleauuplcvels, and remedial action objectives (RAOs) used at the time of thc' rcmedy selection still valid?

Yes.

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7.2.1 Changes in Standards and To-Be-Considered Criteria

• Have Iilere been changes 10 risk-hased cleallllp levels or slalldards idenlilied as ARARs ill Iile ROD Iilal call illlo ljlleSliolllile proleclivelless oflhe rellle(() I?

When the previous FYR was prepared, 2-nitroaniline had a health ri sk-based Preliminary Remediation Goal (PRG) of 110 pg/L in tap water (EPA, 2004). The value of the current Regional Screening Level , which replaced the Region 9 PRGs, is 370 pg/L (El' A, 2009).

During thi s FYR period (2007) the state of Iowa lowered the ambient surface water quality criteria for arsenic III from 360 to 340 pg/L (acute) and tl'om 200 to 150 ~lg/L (chronic) for protection of aquatic lite. These criteria coincide with the recommended tederal surface water quality standards for arsenic (total) for protection of aquatic life are 340 ~lg/L (acutc) and 150 pg/L (chronic) (Table 8). This new standard should not affect the remedy in protecting aquatic life in the Cedar River adjacent to the site. Cedar River sampling is conducted through a 1985 Order on Consent for the LaBounty Site, located across the river tl'Om the Shaw Avenue Dump Site. Concentrations of arsenic were below the surface water quality standard during thi s FYR period.

Changes in the standards identified as ARARs in the 2000 OU2 ROD do not aftect the protectiveness of the remedy because so il has been remediated and ICs prevent exposure to groundwater.

The MCL for arsenic decreased from 50 ~lg/L to 10 pg/L, effective January 23, 2006. There was no MCL for I ,1,2-TCA when the ROD was signed. It now has an MCL of 5 ~lg/L. As shown in Table 9, MCLs for the other potential contaminants of concern identified in the 2000 ROD have remained the same.

The Iowa Action Levels for groundwater are based on a hierarchy consisting of EPA lifetime Health Advisory Levels, EPA negligible risk levels for carcinogens (10.6 ri sks), and te deral MCLs. As shown in Table 10, a litetime Health Advisory Level of 300 ~lg/L has been promulgated for manganese, which becomes the Iowa Action Level for manganese in groundwater. Iowa Action Levels for groundwater have also changed for vinyl chloride, I, l-dichloroethene, and arsenic, based on changes in the negligible risk levels for these potential chemicals of concern since implementation of the ROD.

7.2.2 Changes in Exposure Pathways

• Has lalld lise or e.\pecled lalld lise 011 or Ilear Ihe sile changed (e.g.. indllslriallo residenlial, cOllllllerciallo residenlial) ?

No changes in land use in the surrounding area have occurred since the ROD was implemented. The s ite is bounded by residential areas across Clark Street to the north, east, and northwest and by the Cedar River to the west and southwest. The city wastewater treatment plant is located

20

SH,\ W AVENUE OUMP SITE SECOND FIVE·YEAR REVIEW REPORT

southeast of the former chemical fill area. These land uses are not expected to change in the Ileal' future.

• Have allY h,m,m, health or ecological routes 0/exposure or receptor.l· changed or beell nell'ZV identified (e.g. . derlllal contactll'here none previously existed. nell' populations or .Ipecies identified on site or neal' the site) that could (((feet the protectivel1ess ofthe relllelZ)I?

No human health or ecological routes of exposlll'e or receptors have changed or been newly identi fled that could affect the protectiveness of the remedy.

• Are there nell'ZJ' identified contaminants or contalllinant sources?

No new contaminants or contaminant sOlll'ces were identitied dlll'ing the FYR period.

• Are there unanticipated toxic b)'lJroducts o/the rellledy 110t previouszv addressed by the decisioll docII/llents (e.g.. byproducts not evaluated at the tillle (!fremedy selection)?

No unanticipated toxic byproducts of the remedy have been identified.

• Have physical site conditio/1.l· (e.g. . changes in anticipated direction or rate ((f groundwater .flow) or the understandil1g o.fthese conditions (e.g.. changes in anticipated direction or rate o.fg/'OI/Ildwater.floll') changed in a way that could q(fect the protectiveness o/'lhe remedy?

No changes in site conditions were identifled during this FYR that would affect exposure pathways. There have been no land use changes nor are any land use change anticipated. No new contaminants, sources, or routes of exposure were identified. There is no indication that hydrologic or geologic conditions were inadequately characterized. The contaminant levels in the groundwater are consistent with expectations at the time of the ROD.

7.2.3 Changcs in Toxicity and Other Contaminant Charactcristics

• Have toxicity/actors./or collfaminants ofconcern at the site challged in a way that cOl/ld qfTect the protectiveness o.fthe rellledy?

Changes in toxicity factors do not affect the protectiveness of the remedy because soil has been remediated and ICs controls prevent exposure to groundwater.

As shown in Table 11, oral reference doses have been generated for a number of potential COCs at the site while reductions in reference doses for others increase risks. Only two of the potential chemicals of concern (PCOCs) have had increases in their reference doses (RiDs) resulting in decreased non-cancer risk estimates. These changes clo not , however, affect the protectiveness of the remedy under which exposure is prevented.

In the 1998 ri sk assessment, oral RfDs were usecl as surrogate values for inhalation exposure. These RIDs have been converted to reference concentrations (RfC). As shown in Table 12,

21

SIIAW 1\ VENUE DUtvlP SITE SECOND FIVE·YEAR RE VIEW REPORT

RfCs have been developed for several compounds lhal previously did not have RfCs, and current RfCs for several other COPCs have been lowered resulting in increased ri sk. Risks via inhalation generally constitute II small portion of tota l risk , as shown /01' example in the 1998 Baseline Risk Assessment. Changes in the RfCs do not increase total risk estimates to a degree that affects the protectiveness of the remedy.

With respect to cancer risks, the oral Cancer Slope Factors (CSFs) tor benzene and 1,2-DCA have increased, resulting in increased cancer risk estimates. Oral CSFs for other potential COCs have remained the same, except tor vinyl chloride and I, I-dichloroethene, as shown in Table 13.

Table 14 presents a comparison of inhalation cancer toxicity values. Inhalation slope tactors fi'om the 1998 risk assessment have been converted to inhalation unit ri sks. Most of the values have not changed, but some have decreased or increased. These changes also do not affect the protectiveness of the remedy.

• Have other contaminant characteristics changed in a way that could qtf'ect protectiveness of the remedy?

Other contaminant characteristics have not changed in a way that would affect the protectiveness of the remedy.

7.2.4 Changes in Risk Assessment Methods

• Have standardized risk assessment methodologies changed in a way that cOllld ({[fectthe protectiveness ofthe reme{i)!?

Risk assessment methodologies have not changed in a way that could affect the protectiveness of the remedy. The method of calculating cancer and non-cancer ri sks by the inhalation exposure route were changed in Risk Assessment Guidance tor Superfund (RAGS) Part F (EPA, 2009), but thi s change should not result in ri sk estimate changes sufficient to affect the protectiveness of the remedy.

7.3 Question C: Has any othcl' information come to light that could call into qucstion the protectiveness of the remedy?

7.3.1 Ecological Risl(s

Soils at this site have been remediated. Groundwater is not expected to adversely affect environmental receptors at the site.

7.3.2 Natural Disaster Impacts

No known natural di sasters have occurred that would atIect the protectiveness of the remedy.

22

SIIAW AVENUE L>UivIP SITE SECOND FIVE·YEAR REVIEW REIJORT

7.3.3 Any Othel' Infol'mation That Could Call Into Question the Pl'otectiveness of the Remedy

No other information has been identified that may affect the protectiveness of the remedy.

7.4 Technical Assessment Sunllual'Y

There have been no changes in the physical conditions of the site that would affect the protectiveness of the remedy. According to the documents reviewed and the March 10, 2010, site inspection, the remedy selected by the ESD and OU2 ROD continues to be appropriate and protective. A RARs for groundwater contamination are MCLs. There have been no changes in the risk assessment methodology that could affect the protectiveness of the remedy. No additional information has been identified that would affect the protectiveness of the remedy.

23

SHAW ;\VENUE L>U l\·lP SITE SECOND FIVl ·YlAR REVIEW REPORT

8.0 Issues

No issues or deticiencies were identified during this FYR period that would prevent the remedy Ii'DlIl being protective. Although an increasing arsenic concentration trend was noted in MW-2 indicating downgradient migration in bedrock, ICs remain in place that ensure protectiveness.

Two issues were identified through a review of groundwater monitoring data that require follow­up actions. These issues are identified on the Five-Year Review Summary Form, in Section 6.5, and in Table 1.

24

SHAW AVENUE OWvlP SITE SECOND F1VE·YE/\R REVIEW REPORT

9.0 Recolllmendations and Follow-up Actions

Table 1 present s a list of recommended actions to address the issues identified in Section 6.5. No issues werc identified that would affect current or future protectiveness since ICs remain in place. However, based on an observed increase in arsenic concentrations in MW-2 during thi s FYR period, CENWK provided a recommendation to the EPA RPM that the sampling frequency be increased from biennial to semi-annual. This recommendation was provided to the PRP and implemented during the April 2010 sampling cven!. Sampling of MW-2 will continue on a semi­annual basis.

MW-14, is obstructed and cannot be used for water level collection and cave-ins were evident in open-borehole monitoring well MW-IS. CENWK provided a recommendation to the EPA RPM that MW-14 and MW-IS be visually inspected with a down-hole camera to determine the nature of the obstructions. This recommendation was provided to the PRP and implemented in May 2010.

25

SI-IAW AVENUE DU r>.·11' SITE SECON LJ FIVE-YEAR REVI EW REPORT

10.0 Protectiveness Sta tement

The remedy, inclusive of all OUs at the Shaw Avenue Dump Site, is protective of human health and the environment. All threats at the site have been addressed through excavation and o ffsite di sposal oCthe chemical Ii II ancl surrounding contaminated soil , res that prohibit use of groundwater or intrusive activities, and long-term groundwater monitoring.

26

11.0 Next Review

The next FYR for this site will be conducted within live years of EPA's signed conclll'rence with this FYR. The next FYR is expected to be completed in June 2015.

27

TABLES

TABLE I Recommendations and Follow-Up Actions

Shaw Avenue Dump Site Charles City, Iowa

Issue No,

Recommellda tions andlo,'

Follow-up Actions

Party Responsible

Oversight Agency

Milestone Date

Affects Protectiveness

(YIN)

Current Futu re Increasc monitoring frcqucncy for MW-2

I from biennial to scmi ­annual to more closely

PRP EPA April 2010

N N

monitor increasing arsenic concentrations Obtain scdiment and

2 surface water samples in the Cedar Rivcr adjacent

PRP EPA October

2010 N N

to MW-2

TABLE 2 Chronology of Site Events Shaw Avenue Dump Site

Charles City, Iowa

Event Date Preliminary Asscssment 1984

Proposed for the NPL 1985

Final listing on thc NPL 1987

Removal Assessments 1990, 1991,

1993

Conscnt Order 1988 Remediallnvestigation/Feasibility Study (RIfFS) 1990

Risk Assessment 1991

OUIROD 1991

Explanation of Significant Di fferenccs 1992

Consent Decree 1992

Remedial Design 1992

Remedial Action (OU I) 1994

OU2 R1 1999 OU2 FS 2000

OU2ROD 2000 Environmental Protection Declaration of Rcstrictive Covenants and Eascmcnts

2001

Prcliminary Closeout Report (PCOR) 2001 2002 Revised Site Monitoring and Maintenance Plan 2002 First Five-Year Revicw 2005

N

'5

;\,"§

'n o §

TABLE 3 Summary of Well Construction Details

Shaw Avenue Dump Site Ch:lrles City. low:!

WeliNu. S"o!;;:rop"'/.'

wca/;on

Or;;:;nol Ground

£11"'olion (jL AUSt)

RI.'/I.'''c"cl.' £1C"'urion (/I.AMSL)

OpmHold Scru",:d Im.:,.....'1

Depth (/r.BGS;

Op.'"lIuld Scrl.'t:,,('d [",('n-ol

£kl'ation (/r.AMSI.)

Ground.,'Oter

Elrr.·arion Run;:/.' (It MiSt)

Dafl.' Campkll.'d (mmld'0)')

Cormruc!;on D .. ,uil" (ft. BGS)

MW-l:! Bedrock 1017.3 10\9.22 21.2·69.6 996.1-947.7 1006 - 979 1/3 / 1990 4"0 PVC c:L~ing to 21.2 ', 3"0 open hole to 69.6' well bottom.

MW· 12A Alluvium 1017.1 1019.24 10.0 - \:5.0 1007.1-1002.1 1013 - 1009 iJ9/1990 5.0·long2~0 #10 ~Iot ;:uinkss sted screen. from 10.0' to 15 .0' (well bottom). with 2"0 PVC riser pipe to sUTfucc.

MW-J3 Bedrock 1000.S 1007.86 \1.6-45..1­ 993 .2 - 959.4 990 - 979 111211990 4~0 PVC cn..~ing to 11.6'. 3"0 open hole 10 45.4' well bottom

~W_14 Bedrock 1002.3 To,",

re-surveyed 11.9 - 34.9 990.4-967.4 985 - 979

11811990; converted 10.l flush­

mount on 8111/2009

4"0 pvC C.lsing to 11.9'.3 "0 open hole 10 34.9' well bottom.

\1W-15 Bedrock 1001.3 1003.06 67.0 - 82.5 934.3 - 918.8 980 - 973 11211990 4"0 PVC C:l.'iing to 67.0', 3"0 open hole to 82.5' well bottom.

MW-15A Alluvium 1000.7 1003 .34 41.0-61.0 959.7 - 939.7 981 - 973 1/5/1990 20.0'long: 2"0 #10 slot stainless steel screen. from 41 .0' to 61 .0' (well bottom). with 2"0 PVC riser pipe 10 surf.lce.

MW-ISB Alluvium 1000.9 1003.29 27.6 -47.6 973.3 - 953.3 981 - 973 1211211989 20.0'long 2fl0 fflO slot stainless steel screen. from 27.6' to 47.6' (well bottom). with 2"0 PVC riser pipe to ~urf:l.ce.

MW-16 Bedrock 1002.9 1005 .51 12.6 - 28.3 991.7 - 974.6 992 - 978 8/1611990 4"0 PVC c:l.'iing to 12.6', 3"0 open holt! to 28.3' well bottom.

MW-17 Bedrock - 1005 1007.40 47.0-63.0 - 958 - 942 988 - 977 812011990 4"0 PVC C:l.'iing 10 47.0', 3"0 open hole to 63.0' well bottom

MW-IS Bedrock - 1018 1017.74 22.1 - 42.6 - 996-97) 994 - 980 8fl71l990 4"0 PVC C:l.'iing 10 22.1'. 3"0 open hole 10 42.6' well bottom

MW-ISA Alluvium -lOIS 1017.87 10.0 - 15.0 -1008 ­ 1003 1014- 1011 812111990 5.0'long 2"0 1t 10 slo! st:J.iniL"Ss steel screen. from 10.0' to 15.0' (well bottom). with 2"0 stainks.'i steel riser pipe to surfu.ce.

MW· 19 Bcdrock -1010 1012.95 36.3 - )3 .0 -974 - 957 993 - 978 7114/1992 4"0 PVC C:l.~ing to 36.3'. 3"0 oj)<.'ll hole to 53 .0' wcll bottom. -

;VQ(e.~:

ft. AMSL · feet :J.bovc mC:l.n SC:l. level ft. BGS· fect below ground surf.lce:1.." per d.lte ofwdl inst:!.lbtion 0- Di:l.me!er

Page 2 of 2

TABL E 4 Groundwater Monitoring FrCflllCIICY and Analysis

Shuw Avellue Dump Site Chnl'lcs Cit)', Jowa

Item Id cnti fi cul ion l;' l'eqllf ncy An alys is

Allu\,i;t( '''ells

1v\IV- IA Bienni al VOCs·

MIV- IB I3icllll ia l VOCs·

MIV 2-A NA NA

MW-3A NA NA

1v\ IV-4A NA NA

MIV-4B NA NA

MIV-6A NA NA

MIV-SA NA NA

MIV-1 2A NA NA

MIV-I SA NA NA

MIV-I SB NA NA

MIV- 18A NA NA

Bedroel< Wells (UCV A)

MIV-I Bie nnial VOCs·

1v\IV-2 Bienni al Arseni c, VO Cs'" 1v\IV-3 NA NA

MIV-4 Bienn ia l Arseni c

1v\IV-6 Semi-Annuli l Arsenic

Biciltl iui Arseni c

MIV-7 Semi-Annual Arseni c

Biellnial Arseni c

MIV-S Seln i-Annuul Arseni c

Bie lln ial Arsenic

MIV-9 Biennial Arsenic

MIV- IO Biennial Arsenic

MIV- II Biennial Arsenic

MIV-1 2 Biennial Arsenic

MIV-1 3 NA NA

MIV- 14 Bienn ial Arse nic

MIV-I S Biennial Arse nic MIV- 16 NA NA

MIV- 17 Bi cllninl Arsenic

MIV-I S NA NA

MIV -I Y Biennial Arse nic

Nuln:

UCVA: Upp,:rCedar Vallc), Aquifer

• R<,porl<.-d VOCs include Vin)'1 Chlorid<.', 1.1-Uid dorOl.'lh':IK'. 1.2-[)ich\orocltwllc amI l ,l,2-TridlloroC'lhanc

Wa t.:r lewIs collec ted rrom all s i t~ wdls on a s~ IlI i-:,"nuJl blSis

NA "" Not SampkJ

Page 1 of 1

TABLE 5

QIl~rtel'ly Gl'oundwnler Ele\'ntiolls Post au I Remediation Groundwater Monitoring

Shaw Avellue Dump Site Charles City, Iowa

MOl/ilori"K Top o/Casing GWlllulll'a(cl'

Well Elel'{llioll Elel'tllioll (ft. ,fMSL)

ID (ft. A,\/SLj Apr-05 Oct-05 tfpr-06 Oc/-06 ...11'1'-07 Ocl-07

IvlW-l 992.55 975.12 974.60 977.04 974.12 975.92 977.76

MW-IA 993.44 975 .06 974.54 976.97 974.07 975.89 977.72

tv1W-1B 993.49 975.07 974.53 976.96 974.06 975.88 977.72

i\'IW-2 986.48 975.39 974.78 977.32 974.3 I 976.15 977.97

r...IW-2A 986.32 975.20 974.50 977.0 I 974.11 975.88 977.61

tvlW-3 990.78 975.09 974.71 977.08 974.12 976.33 978.58

tv1W-3A 991.14 975.03 974.53 977.0 I 973 .96 975.98 978.34

~nV-4 993.05 975.71 975.22 978.03 974.54 976.40 978.48

l\nV-4A 992.43 975.54 975.04 977.85 974.36 976.23 978.30

r-.nV-4B 992.21 975.54 975.06 977.87 974.36 976.23 978.28

tvlW-6 1004.62 982.02 979.52 983.22 978.06 983.47 9&7.39

r...IW-6A 1004.59 975.84 975.38 978.31 974.7 977.21 980.58

l\nV-7 1006.43 980.86 980.22 983.90 977.98 984.15 989.77

r...IW-8 1013.64 992.59 983.82 986.44 982.48 986.74 996.69

tvtW -SA 10ll.S9 Dry 994.79 Dry Dry 994.84 996.76

tvlW-9 998.01 977.58 977.08 979.52 976.38 979.74 981.88

tI.'I\"-10 995.53 978.34 979.28 983.85 976.8 984.65 989.17

ivlW-ll 1006.50 984.00 983.49 986.99 980.94 987.83 992.75

iv1\V­12 1019.22 986.04 984.88 988.53 982.36 989.52 993.08

tvIW-\2A 1019.24 1010.76 1011.1S 1012.17 1010.34 1012.57 10ll.12

MW-13 1007.86 989.43 983.78 987.30 982. 12 988.19 990.23

MW-14 1004.82 NA NA NA NA NA NA j\,IW-[5 1003.06 975.47 975.01 977.82 974.34 976.16 977.84

tl.HV-15A 1003.34 975.42 974.96 977.80 974.29 976.12 978.43

i\'IW- \58 1003.29 975.39 974.94 977.75 974.26 976.08 978.05

l\nV-16 1005.51 981.69 983.77 987.49 981.88 987.43 992.58

:...IW-17 1007.40 983.15 982.12 984.61 981.97 985.48 988.67

i'vIW-18 1017.74 NA NA NA NA NA NA 1'\'IW-JSA 1017.87 1012.73 1012.77 1012.SS 1012.69 1013.23 1014.00

1\:IW-19 1012.95 985.09 983.93 987.67 981.J7 988.30 993.05

NoleJ:

NT - Not Taken

NA · Not A\'ailable

ft. A,\ISL - feci above me-an sea level

Page 1 of 2

TABLES

Quarterly Gl'oundwater Elevations

Post au I Remedi:tlioll Gl'oundwaler Monitoring Shnw A vcnue DUlIlp Site

Chal'les City, lown

Mallito,.;ug Top oICas;"g Grollllrlll'alt!1'

Well Hlcl'tllioll EtCI'iI/ioll (ft. AMSL)

ID (ft. AMSL) 11/tl.l'-08 0('/·08 /lpr-09 Ocl·09

~nV-J 992.55 975.59 973.89 973.95 973.69 tvl\V-IA 993.44 975.55 973.85 973.92 973.72 r...fW-1B 993.49 976.35 973.85 973.92 973.71 rvlW-2 986.48 975.63 974. 14 974.19 NT MW-2A 986.32 975.26 973.94 973.97 NT tv!\V-] 990.78 975.88 973.94 973.96 973.94 r-.nV-3A 99 1.1 4 975.71 973.66 973.75 973.62 ivlW-4 993.05 976.10 974.30 974.40 NT MW-4A 992.43 975.93 974.12 974.21 NT

tv1W-4B 992.21 975.93 974.12 974.21 NT tvlW-6 1004.62 981.42 977.43 977.46 979.21 1\'1\\'-6/\ 1004.59 976.62 974.55 974.56 974.74 MW-7 1006.43 981.78 976.93 977.08 978.92 1\1\\' -8 10 13.64 984.47 982.44 982.47 982.92 MW-SA 10 1.l.89 994.85 994.80 994.77 994.78 MW-9 998.01 979.0 1 975.95 976.03 977.20 MW-IO 995.53 983.59 976.69 977.33 980.97 1\-1\V-1 1 1006.50 986. 11 980.3 1 980.86 982.81

1\<I\V-12 10 19.22 987.73 98 1.75 982.12 984.41

1\nV- 12A 1019.24 1012.04 10 10.12 101 1.05 1010.90 MW- 13 1007.86 985.61 980.37 980.35 982.33 MW- 14 1004.82 NA NA NA NA 1\nV-1 5 1003.06 975.94 974.03 974. 16 973.96 f\-I\V -J5A 1003.34 975.91 974.02 974. 12 973.93 MW-\S8 1003.29 975.89 973.99 974. 11 973.90 MW-16 1005.5 1 986.90 980.08 982.30 982.62 MW-17 1007.40 983.07 979.79 979.36 98 1. 20 f\'1\V-J8 101 7.74 NA NA NA NA f\HV - JSA 1017.87 1012.83 10 12.58 1012.55 101 3.24 1\-I\V -19 1012.95 986.69 981.10 981.20 983.91

Noh's:

NT - Not Tak(,ll

NA - No t Available

n.I\~ISL - fec Iabov\! mean sea lewl

Page20f 2

TABLE 6 Groundwater Monitoring Results Summary 2004-2009

Shaw Avenue Dump Site Charles C ity, Iowa

MW--1

Vl0/2003 10//iI2003 ;15/2004 111'-/2004 10/112006 10/11/2008

Volatile Organic Compounds (PgIL)

Vinyl Chloride NDl (NDl) NDl NDIMI l;l~Dichloroethenc ND2(N02) ND2 ND2Ml 1,2-Dichloroethanc NDl (NOl) NDl NDl I ,I,2-Trichloroethane NDl (NOl) NDl NOl

Metals (PgIL)

Arsenic (Total)

Notes: U Moni toring well to be sampled biennially for vinyl chloride, 1,1-dichloroethene, l,2-dichloroethane, 1,1,2-trich1oroethane, per 2002 revised Si te M&M Plan

Monitoring well to be sampled semi-annually for total arsenic concentrations, per 2002 revised Site M&M Plan Monitoring well to be sampled biennially for total arsenic concentrations, per 2002 revised Site M&M Plan

() - Analysis of duplic<lte sample

- - Analysis was not conducted for this parameter NA - Not Available Ml - The MS and/or MSD were outside control limits

NDl- Non Detect: Method detection limitofl~g/L

ND2- Non Detect: Method detection limit of l~S/L Modified from Conestoga-Rovers & Associates annual monitoring repons

Page 1 of 17

TABLE 6 Groundwater Monitoring Results Summary 2004-2009

Shaw Avenue Dump Site Charles City, Iowa

MW~/A

51512004 111212004 101112006 1011112008

Volatile Organic Compounds (pg/L)

Vinyl Chloride NDl NDl ND! (NO!)

1, \-Dichlorocthcnc N02 ND2l N02 (ND2)

1.2-Dichlorocthanc NDl NDl J I<Dl (NDl) 1.1.2-Trichloroethanc 3.1 1.79 2.21 (2 .04)

Metal:; (pgIL)

Arsenic (Total)

Notes:

U MonitOring wel l to be sampled biennially for vinyl chloride. 1.1-dichlorocthcnc. 1.2-dichlorocthanc. 1.1.2-trichlorocthanc. per 2002 rcvi!:cd Site M&M Plan

Monitoring well to be sampled semi-annually for total arsenic concentrations. per 2002 revised Site M&M Plan

Monitoring well to be sampled biennial!y for total arsenic concentrations. per 2002 revised Site M&M Plan

( ) - Analysis ofduplicate sample

- • Analysis was not conducted for this parameter

NA· Not Available J - Analyte detected at a lcvellcs.s than the Reponing Limit and greater than or equal to the Method Detection Limit. Concentrations \v1thin this range arc estimated

N01· Non Detect: Method detection limit of llJ.g/L N02· Non Detect: Method detection limit of lllg/L Modified from Conestoga· Rovcrs & Associatcs annual monitoring repom

Page 2 of 17

•

TABLE 6 Groundw ater Monitoring Results Summary 2004-2009

Shaw A venue Dump Site Charles City, Iowa

MW-IB

5/512004 /1/2/2004 1011/2006 10/11/2008

Volatile Organic Compounds (pglL)

Vinyl Chloride NO! NO! ND! I,l-Dichlorocthcnc NO:! N02 J N02

I.2-Dichlorocth:mc NO! NOI J NO!

1.1.2-Trichlorocthanc ND! 1.5 1.24

Metals (pgIL)

Arsenic (Total)

Notes:

D Monitoring well to be sampled biennially for vinyl chloride. I.l-dichlorocthcnc. 1.2-dichlorocthanc. I, 1.2-trichlorocthanc. per 2002 revised Site M&M Plan

Monitoring well to be Slmplcd semi-annually for tCUlI arsenic concentrations. per 2002 revised Site M&M Plan

Monitoring well to be sampled biennially for total arsenic concentrations, per 2002 revised Site M&M Plan

( ) - Analysis of duplicate sample

-- - Analysis was not conducted for this parameter

NA - Not Available

J • Analyte detected at a levclless than the Reporting Limit and greater than or equal to the Method Detection Limit. Concentrations within this range are estimated

ND1- Non Detect: Method detection limit of l)lg/L ND2- Non Detect: Method detection liInit of l).lg/L Modified from Conestoga-Rovers & Associatcs annual monitoring reports

Page 3 of 17

TABLE 6 Groundwater Monitoring Results Summary 2004-2009

Shaw Avenue Dump Site Charles City, Iowa

MW-2

51512004 11/112004 101112006 10111/2008

Volatile Organic Compounds (pgIL)

Vinyl Chloride 1.8 1.52 (1.43) 1.62 1. I-Dichlorocthenc ND:? ND2 J (N02 J) ND2

1.2-0ichlorocthanc NDI 1.07 (1.07) 1.28

1.1.2-Trichlorocthanc NDl NDI (ND I ) NDI

Metals (pg/L)

Arsenic (Total) 162 528 (526) 954Ml

Notes:

c=JMonitoring well to be sampled biennially for vinyl chloride. ! .1-dichlorocthcnc. 1.2-dichlorocthanc. 1.1.::?Arich!orocthanc. per 2002 revised Site M&M Pl:;m

Monitoring well to be sampled semi-annu:tlly for total arsenic concentrations. per 2002 revised Site M&M Plan

Monitoring well to be sampled biennially for total arsenic concentrations. per 2002 revised Site M&M Plan

( ) - Analysis ofduplicate sample

- • Analysis was not conducted for this parameter

KA· Not Available J . Analyte detected at a level less than the Reporting Limit and greater than or equal to the Method Detection Limit. Concentrations with in this range are estimated

MI· The MS and/or MSD were outside control limits NDl· Non Detect: Method detection limit of ll!g/L ND2· Non Detect: Method detection limit of 1I!S/L Modified from Conestoga· Rovers & Associates annual monitoring reports

Page 4 of 17

TABLE 6 Groundwater Monitoring Results Summary 2004-2009

Shaw Avenue Dump Site Charles City, Iowa

MW-2A

5/512004 111211004 101211006 1011612008

Volatile Organic Compounds (pg/L)

Vinyl Chloride NA NO! NO!

1.1-Dichlorocthcnc NA N02l N02

1.2-Dichloroethane NA NO] NO] 1.1.2-Trichlorocthanc NA NO] NO ]

Metal... (pg/L)

Arsenic (Total) NA

Notes:

c=JMonitoring: well to be sampled biennially for vinyl chloride. 1.1 ~ichlorocthcnc. 1.2-dichlorocth::lnc. 1.1.2-trichlorocthanc. per 2002 revised Site M&M Plan

Monitoring well to be sampled semi-annually for total arsenic concentrations. per 2002 revised Site M&M Plan

Monitoring: well to be sampled biennially for total arsenic concentrations. per 2002 revised Site M&M Plan

( ) - Analysis ofduplicate sample -- - Analysis was not conducted for this parameter

NA - Not Available

J - Analyte detected at a levc11css than the Reporting Limit and greater than or equal to the Method Detection Limit. Coneentr:ttions within this r:tnge arc estimated

NDl- Non Detect: Method detection limit of lJ.lS/L

ND2.- Non Detect: Method detection limit of lJ.lS/L ModifiL'd from Conestoga-Rovers & Associates annUlI monitoring reports

PageS of 17

TABLE 6 Groundwater Monitoring Results Summary 2004-2009

Shaw Avenue Dump Site Charles City, Iowa

MW-4

51512004 11/2/2004 101212006 10/1112008

Volatile Organic Compounds (pglLJ

Vinyl Chloride

1.1-0ichloroethenc

l.2-Dichloroethane 1.1.2-Trichlorocthane

Metals (pg/LJ

Arsenic (Total) 2.1 2.95 1.64

Notes:

Monitoring. well to be sampled biennially for vinyl chloride. 1.1-dichlorocthcnc. 1.2-dichlorocth:mc. 1.1.2-trichlorocthanc. per 2002 revised Site M&M Plan

Monitoring: well to be sampled semi-annually for total arsenic concentrations. per 2002 revised Site M&M Plan

Monitoring well to be sampled biennially for total arsenic concentrations. per 2002 revised Site: M&M Plan

( ) - Analysis of duplicate sample

-- - Analysis was not conducted for this paramctcr

NA - Not Available

Modified from Conestoga-Rovers & Associates annual monitoring reports

Page 6 of 17

TABLE 6 Groundwater Monitoring Results Summary 2004-2009

Shaw Avenue Dump Site Charles City, Iowa

51512004 111112004 4/1312005 1011412005 412412006 101112006 4117/1007 / 0/101200i 51/ 512008 10/ 1112008 4/1412009 JOliaOO9

Vola tile Organic Compounds (p.gIL)

Vinyl Chloride

1. 1· 0ichlorocthcnc

1.2-Dichloroethanc 1. 1.2-Trichlorocthanc

Metals (pglL)

Arsen ic (Total) 427 278 253.3 243 291 (327) 114 213 (202) 256 (253 ) 270 143 14 1 MI ( 121 ) 174 MI ( 170)

Noles:

U Monitorin,g well to be sampled b iennially for vinyl ch loride. I. l -dichlorocthcnc. 1.2-<iichlorocthanc. 1. 1.2-trichloroethanc. per 2002 revised Site ~&M Plan

Monitoring well to be sampled semi-annually for total arsenic concentrations. per 2002 revised Site M&M Plan

Monitoring well to be sampled biennially for total arsenic concentrations. per 2002 revised Site M&M Plan

( ) - Analysis of dupl icate s;J.mple

-­ - Analysis was not conducted for this parameter

NA - Not Available

M I - The MS and/or MSD were outside control limits

Modified from Conestoga-Rovers & Associates annual monitoring reports

Page 7 of 17

TABLE 6 Groundwater Monitoring Results Summary 2004-2009

Shaw Avenue Dump Site Charles City, Iowa

MW:7

5/512004­ 1//112004 41/312005 1011412005 412412006 101112006 4/Ji/2007 1011012007 5/1512008 1011112008 4124/2009 IO/i/2009

Volatile Organic Compounds (pgIL)

Vinyl Chloride

1.1-Dichloroethene

l .2-Dichloroethane 1.1.2-Trich lorocthanc

Metals (pglL)

Arsenic (Total) 76 .9 88 .0 104.8 (107.9) 96 (96) N01 190 120 128 152 ( 149) 190 139 154

Notes:

c=JMonitoring well to be sampled biennially for vinyl ch loride. I. l -dichlorocthenc, 1.2-dichloroethanc. 1.1.2-trichlorocthanc. per 2002 revised Site M&M Plan

Monitoring well to be sampled semi-annually for total arsenic concentrations. per 2002 revised Site M&M Plan

Monitoring well to be sampled biennially for total arsenic concentrations. per 2002 revised Sitc M&M Plan

( ) - Analysis of dupl icate sample

-­ - Analysis was not conducted for this parameter

NA - Not Avai lable

NDl- Non Detect: Method detection limit of lJ..lg/L Modified from Conestoga-Rovers & Associates annual monitoring reports

Page80f 17

TABLE 6 Groundwater Monitoring Results Summary 2004-2009

Shaw Avenue Dump Site Charles City, Iowa

MIr.8

5/512004 , 1/412004 4/1212005 1011512005 412412006 101512006 4/1712007 1011012007 5/16/1008 10/14/2008 4/2412009 101812009

Volatile Organic Compounds (pgiL)

Vinyl Chloride

1.1 -Dichloroethene

1.2-Dichloroethane

1.1.2-Trichlorocthanc

Metals (pg/L)

Arsenic (Total) 2590 2200 502 1980 389 NA 364 152 1050 NA 362 1260

Notes:

C]Monitoring well to be sampled biennially for vinyl chloride. l.l-dichloroethcnc. 1.2-dichlorocthanc. I, 1.2-trichlorocthane. per 2002 revised Site M&M Plan

Monitoring well to be sampled semi-annually for total arsenic conccntr.l.tions. ~r 2002 revised Site M&M Plan

Monitoring well to be sampled biennially for total arsenic concentrations. per 2002 revised Site M&M Plan

( ) - Analysis ofduplicate sampJc

-­ - Analysis was not conducted for this parameter

NA - Not Available

Modified from Conestoga-Rovers & Associates annual monitoring rcpons

Page90f 17

TABLE 6 Groundwater Monitoring Results Summa ry 2004-2009

Shaw Avenue Dump Site Charles City, Iowa

MW-9

51512004 /11412004 1011/2006 1011312008

Volatile Organic Compounds (pglL)

Vinyl Chloride

1.1-Dichlorocthcnc

1.2-Dichlorocth:mc

1. 1.2-Trichlorocthanc

Metals (pglL)

Arsenic (Total) 7.1 14.2 3.96

Notes:

c=JMonitoring well to be sampled biennially for vinyl chloride. 1.1 -dichlorocthcnc. 12-dichlorocthanc. 1.1.2-trichlorocthanc, per 2002 revised Site M&M Plan

Monitoring: well to be sampled semi-annually for total arsenic concentrations. per 2002 revised Site M&M Plan

Monitoring: we1J to be sampled biennially for total arsenic conccntrntions. per 2002 revised Site M&M Pbn ( ) - Analysis ofduplicate sample

-- - Analysis was not conducted for this parameter

NA - Not Available

Modified from Conestoga-Rovers & Associates annual monitoring reports

Page 10 of 17

TABLE 6 Groundwater Monitoring Results Summary 2004-2009

Shaw Avenue Dump Site Charles City, Iowa

MW-IO

5/512004- J 11212004 101312006 10/11/2008

Volatile Organic Compounds (pgIL)

Vinyl Chloride

l.l-Dichlorocthcnc

1.2-Dichloroethane 1. 1.2-Trichlorocthanc

Metals (pglLJ

Arsenic (Total) 2.0 (2 .S) 5.6 3.13

Notes:

U Monitoring well to be ~mplcd biennially for vinyl chloride. 1.1-dichlorocthcnc. 1.2-dichloroethanc. 1.1.2-trichlorocthanc. per 2002 revised Site M&M Plan

Monitoring well to be s:lmplcd semi-annually for total arsenic concentrations. per 2002 revised Site M&M Pbn

Monitoring: well to be sampled biennially for total arsenic concentrations. per 2002 revised Site M&M Plan

( ) - Analysis ofduplicate sample

.- - Analysis was not conducted for this parameter

NA - Not Available

Modified from Conestoga-Rovers & A'>sociatcs annual monitoring reports

Page 11 of 17

TABLE 6 Groundwater Monitoring Results Summary 2004-2009

Shaw Avenue Dump Site Charles City, Iowa

MW·/l

51512004 /11412004 101412006 10/1311008

Volatile Organic Compounds (Jig/L)

Vinyl Chloride

1.1 -0ich lorocthcnc

1.2-Dich loroethane 1.1.2-Trichlorocthanc

Metals (pg/L)

Arsenic (Total) 141 .5 109 M l 3 !.S

Noles:

c=]Monitoring: well to be sampled biennially for vinyl chloride. 1.1-dichlorocthcnc. 1.2-dichlorocthanc. 1.1.2-trichlorocthanc. per 2002 revised Site M&M Plan

Monitoring well to be sampled scmi-::lnnually for total arsenic concentrations. per 2002 revised Site M&M Plan

Monitoring well to be sampled biennially for total arsenic concentrations. per 2002 revised Site M&M Plan

( ) - Analysis ofduplicate sample

-- - Analysis was not conducted for this parameter

NA - Not Available

M I - The MS and or MSD were outside control limits

Modified from Conestoga-Rovers & Associates annual monitoring rcpons

Page 12 of 17

TABLE 6 Groundwater Monitoring Results Summary 2004-2009

Shaw Avenue Dump Site Charles City~ Iowa

MW-1 2

5/512004 111412004 101412006 1011412008

Volatile Organic Compounds (pglL)

Vinyl Chloride

l.l-0ich loroethenc

l.2-Dich loroethanc I , I .2-Trichlorocthanc

Metals (pg/L)

Arsenic (Taul) 9.4 9.S 12.7

Notes:

D Monitoring well to be sampled biennially for vinyl chloride. 1.1-dichlorcx.'"thcnc, 1.2-dichloroethanc. 1.1.2-trichlorocthane. per 2002 revised Site M&M Plan

Monitoring well to be sampled semi-annually for total arsenic concentrations. per 2002 revised Site M&M Plan

Monitoring well to be sampled biennially for total arsenic concentrations. per 2002 revised Site M&M Plan

( ) - Analysis ofduplic:ltc ~mplc

-- - Analysis was not conducted for this parameter

NA - Not Available

Modified from Conestoga-Rovers & Associates annual monitoring reports

Page 13 of 17

TABLE 6 Groundwater Monitoring Results Summary 2004-2009

Shaw Avenue Dump Site Charles City, Iowa

MWM/4

5/512004 111212004 1011211008

Volatile Organic Compounds (pg/L)

Vinyl Chloride NA NA 1.1-Dichloroethcnc NA NA 1.2-Dichlorcx.--r.h:mc NA NA 1.1.2-Trich loroethane NA NA

Metals (pglL)

Arsenic (Total) NA NA

Notes:

l Monitoring well to be sampled biennially for vinyl chloride. 1.1-dichlorocthcnc. 1.2-dichlorocthanc. 1. 1.2-trichlorocthane. per 2002 revised Site M&M PInn

Monitoring well to be sampled semi-annually for towl arsenic conccntro.tions. per 2002 revised Site M&M Plan

Monitoring well to be sampled biennially for total arsenic concentrations. per 2002 revised Site M&M Plan

( ) - Analysis ofduplicate sample

-- - Analysis was not conducted for this parameter

1\'A - Not Available

Modified from Conestoga-Rovers & Associates annual monitoring reports

Page 14 of 17

TABLE 6 Groundwater Monitoring Results Summary 2004-2009

Shaw Avenue Dump Site Charles City, Iowa

MW-15

51512004 J11212004 101112006 10/1212008

Volatile Organic Compounds (pglLJ

Vinyl Chloride

1.1-Dichloroethcne

1.2-Dichlorocthane

1.1.2-Trichlorocthanc

Melals (pg/L)

Arsenic (Total) 5.2 6.12 5.51

NOles:

U Monitoring well to be sampled biennially for vinyl chloride. 1.1-dichlorocthcnc. 1.2-dichlorocthanc. 1.1.2-trichlorocthanc. per 2002 revised Site M&M PIan

Monitoring well to be sampled semi-annually for total arsenic concentrations. per 2002 revised Site M&M Plan

Monitoring well to be sampled biennially for total arsenic concentrations. per 2002 revised Site M&M Plan

( ) - Analysis ofduplicate sample

-- - Analysis was not conducted for this parameter

J\A - Not Available

Modified from Conestoga-Rovers & Associates annUlI monitoring: reports

Page 15 of 17

TABLE 6 Groundwater Monitoring Results Summary 2004-2009

Shaw Avenue Dump Site Charles City, Iowa

MW-17

5/512004 J 1/1/2004 1012/2006 10/12/2008

Volatile Organic Compounds (pgIL)

Vinyl Chloride

1.1-Dichlorocthcnc

1.2-Dichloroethane

1.1.2-Trichlorocthanc

Metals (pglL)

Arsenic (Total) 3.9 3.8 8.21 (8.20)

Notes:

D Monitoring well to be sampled biennially for vinyl chloride. 1.I-dichloroethenc. 1.2-dichloroethane. 1. 1.2-trichlorocthanc. per 2002 revised Site M&M Plan

Monitoring well to be sampled semi-annually for total arsenic concentrations. per 2002 revised Site M&M Plan

Monitoring well to be sampled biennially for total arsen ic conc:cntI'3tions. per 2002 revised Site M&M Plan

( ) - Analysis of dupliCJ.tc sample

- - Analysis was not conducted for this parameter

NA - Not Available

Modified from Conestoga-Rovers & As.."0Ciatcs annual monitoring reports

Page 16 of 17

TABLE 6 Groundwater Monitoring Results Summary 2004-2009

Shaw Avenue Dump Site Charles City, Iowa

MW-19

51512004 11/412004 101412006 101/412008

Volatile Organic Compounds (pg/LJ

Vinyl Chloride

1.1-Dichlorocthcnc

1.2-Dichlorocthanc 1.1.2-Trichlorocthanc

Metals (pgIL)

Arsenic (TouJ) 129.1 117(1 23) 104

NOles:

D Monitoring well to be sampled biennially for vinyl chloride. 1. I-dich lorocthi."TlC. 1.2-dichlorocthanc. 1.1.2-trichloroethanc. per 2002 revised Site M&M Plan

Monitoring well to be sampled scmi-:mnually for total arsenic conccntr.ltions. per 2002 rcviS<.--d Site M&M Pl:m Monitoring well to be sampled biennially for total arsenic conccntr::nions. per 2002 revised Site M&M Plan

( ) - Analysis ofduplicate sample

-- - Analysis was not conducted for this par.lmctcr NA - Not Availab le

Modified from Conestoga-Rovers & Associates annuo.l monitoring reports

Page 17 of 17

TABLE 7 Daily Locall'recipitation

2005-2009 Shaw Avenne DlllllP Site

Charles City, Iowa

Precipitatioll (im'IIt's)

2005

Dale JIIII. Feb. Mar. Apr. MIIJ' JIII/. Ju/. Aug. Scpt. Oct. lYO)'. De£',

I

2

3

4

5

6

7

S

9

10

I I

12

13

14

15

16

17

18

19

20

2 1

22

23

24

25

26

27

28

29

30

31

0.29

T

T

0.01

T

0.30

0.55

T

T

T

0. 11

T

0.01

0.01

T

T

0.05

0.03

T

T

0.69

0.30

0.14

0.57

T

0.0 1

0.24

0.07

0.0 1

0.01

T

0.03

0.55

1.13

T

0.49

1.48

0. 17

T

T

T

0.42

0.17

0.17

0.01

0.07

0.Q2

T

T

0.52

2.62

0.35

0.34

T

0.01

0.28

1.08

1.00

1.52

0.02

0.02

0.37

T

T

0.41

0.23

0.73

0.63

0.01

0.18

0.88

0.6 1

T

T

T

T

1.29

1.0 I

1.39

T

0.32

T

0. 16

T

T

0.07

0.06

0.09

0.05

OJ I

T

0.37

0.10

1.00

T

T

T

T

T

T

T

T

TOTAL 0.30 0.85 0.21 2.04 4.71 7.76 2.56 1.49 4.01 0.29 1.92 0.00

NtJldd:

Total precipi tation recorded as inches (water equivalent).

Source: Nationa l Weather Service Forecast Olliee, La Crosse, Wisconsin (www.crh.tloaa.gov/arxfcl imate)

T = Trace «0.0 1" prccipit3tion)

Sn:= Snow

Page1of5

TABLE 7 Daily Local Precipitation

2005-2009 Shaw Avenne Dump Site

Charles City, Iowa

Pre£"ipilflfiou (iltches)

2006

Date Jalt. Feb. Mur, AI' I'. May JIIII , Jul. Allg. Sept. Ocl. iVOI'. OeL',

I

2

3

4

5

6

7

8

9

10

I I

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

3 1

0.13

T

T

T

T

T

0.18

T

T

T

T

T

T

T

0.46

0.0 1

0. 18

0.49

0.09

0.73

0.10

T

0. 17

0.Q2

0. 14

0.58

1.26

0.04

0.01

0. 11

T

0.02

0.Q7

0.86

0.77

0.08

T

0.11

0.03

0.37

0.06

0.02

0.06

0. 15

0.02

T

T

0.04

0.05

0.05

T

0.38

0. 15

0.3 1

0.95

T

0.76

0.31

0.41

T

0.54

0.52

0.Q2

T

T

T

0.03

0.26

0.55

0.05

0. 18

1.22

0.0 1

0.11

0.16

T

0.33

0.29

0.Q7

0.Q4

0.72

T

0.16

0.20

0. 13

0. 15

0.30

T

1.88

0.94

T

0.0 1

0.37

0.4 1

T

T

0.Q2

0.06

0. 10

0. 14

0.56

0.01

0.16

T

0.Q7

0.01

T

0.25

0.26

0.90

T

T

0. 11

0.22

0.01

0.44

0.59

0.21

TOTAL 0.3 1 0.00 2.06 4.05 1.04 4.33 2.32 2.08 4 .27 1.05 1.41 1.58

/VoId"' :

TOlal preci pitation recorded as inches (water equivalC'n t).

Source: Nationa l Weather Sen'ice Forecast omcc, La Crosse, Wiscons in (www,crh.lIona.gov/ar.uc1imate)

T = Tmce «0.01" precipitation)

SII "'" Snow

Page20f 5

TABLE 7 Daily Local Precipitation

2005-2009

Shaw A venne DUIlI» Si te Charles City, Iowa

Pre£'ipilalio/l (il/du's)

2007

Dute JUII. Feb. Mar. Apr. ll/flY JIIII . Jul. Aug. Sept. OCI. IVOI'. /Je£',

I

2

3

4

5

6

7

8

9

10

I I

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

T

T

T

T

T

T

T

T

T

T

0.01

T

T

0,48

T

0.09

0,47

0 .17

0.37

T

0.19

0.58

1.06

0 .39

T

0. 18

0.57

0.09

T

T

0.31

T

T

T

T

0,48

0.80

T

0.06

0.01

0.61

0.05

0 .96

T

0.34

0.01

1. 23

1.3 1

0 .13

T

T

T

0.02

1.90

1.1 6

0.75

0,49

0.64

1.09

0.37

0.28

T

T

T

T

0.83

T

1. 19

6.33

0.05

0.98

0. 12

T

0,46

0.78

T

T

1.10

T

0.60

0.01

0 .02

0. 16

T

0 .12

T

0.04

0.36

T

1.83

T

0.25

2.50

0 .01

0.83

T

0.02

0 .22

0.53

0.03

0. 14

T

T

T

T

0.04

T

T

T

T

T

T

T

T

T

T

T

TOTAL 0.00 0.00 1.05 2.76 2.50 4 .64 4.96 12,48 2,41 6.36 0.04 0.00

No /I'{sJ:

Total pn.'cip ilntioll recorded us inc hes (water equiva lent).

Source: Nation,,] Weather Service Forecast Onice, La Crosse, Wisconsin (www.crh.nollu.gov/nrx/cl imatc)

T = Trace «0.0 1" precipitation)

Sn = Snow

Page30f 5

TABLE 7 Daily Local PrecilJitation

2005-2009 Shaw Avenne Dnmp Site

Charles City, Iowa

Precipifation (il/"II t':,)

2008

Dale .lUll. Feb. Mar. Apr. ,\IllY .11111. JI//. Allg. Sept. 0('1. Nm'. Det',

I

2

3

4

5

6

7

8

9

10

II

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

T

0.18

T

T

T

T

T

T

T

T

T

T

T

T

0. 17

0.11

0.0 1

T

T

T

0.01

0. 18

T

1.29

T

T

0.1 1

0.25

0.3 7

1.45

T

0 .0 1

0 .1 4

0.87

1.07

0.07

T

0. 34

0.0 1

0.46

0.03

T

0. 13

0.0 1

T

T

T

T

0.06

1.24

T

1. 77

0. 18

T

0.27

0.35

T

0.06

0.63

1.25

0.D2

0. 15

0.02

0.01

0.55

0. 16

T

1.48

0.82

0.28

0.8 1

1.1 2

0.04

0.33

0. 17

T

0.20

T

0.25

0.05

0,07

0. 10

0.45

0. 19

0.03

0.0 1

0.08

0. 18

0.40

T

T

0. 12

0.08

0.47

0.D2

0.59

0.18

1.38

0.25

0. 11

0.34

0.03

T

0.13

T

0. 15

0.60

0. 13

0.02

0.44

0.09

0.25

0.09

T

T

T

T

T

T

T

0.D2

T

T

0. 16

TOTAL 0.18 0.00 1.77 4.34 4.23 3.47 5.05 1. 12 2. 17 2.42 1.77 0.18

Nol('(s):

Toio l precipitation recorded as inches (water equ ivolenl).

Source: Nationa l Weather Service Forecast Ofl1ce, I.a Crosse, Wisconsin (www.crh.noaa.gov/n rx/cl imalc)

T = Tmce «0.0 I" precipitation)

Sn = SIlOW

Page 4 of 5

TABLE 7

Daily Loca l Precipitation 2005-2009

Shaw Avenne Dnlllp Site Charl es City, Iowa

i'n.'(:ipilaliolt (illdtes)

2009

Dale Jill/ , Feb. Mar. Apr. May JIlII. Jul. Allg. Sept. Od. NOI'. D"t" I

2

3

4

5

6

7

8

9

10

II

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

3 1

T

T

T

T

T

T

T

T

0.07

0.03

0.01

0. 16

T

0.81

0.07

0.09

0.02

T

0.0&

T

T

0.28

T

0. 11

T

0.0 1

0.27

0.83

2.04

0.29

0.34

0.21

0.73

0.15

T

1.45

0.09

0.65

0.05

0.25

0.02

1.49

T

T

0.10

0.23

0.20

T

0.11

0.02

0.89

0.43

0.45

0.04

T

0.Q2

0. 12

T

0.23

0.19

1.64

T

0.54

0.40

0.01

T

0.20

T

T

0.02

0.70

0.04

0.2 1

0.64

0.09

O.QI

0.59

0. 16

0.11

0.22

0.0 1

0.0 1

T

0.3&

0.41

0.0 1

1.29

1.89

0. 15

0.Q2

0.24

0.60

0.03

0.18

0.14

T

0.07

0. 16

1.0 I

0.&9

0.20

T

0.05

1.90

0.08

0.08

T

0.07

0.07

0.4 1

0.05

T

TOTAL 0.00 0.27 1.07 4.38 4.88 2.47 3.35 2.8 1 2.09 7.6 1 0.68 0.00

!VoId\):

Tutul precipitation rl'corded as inches (w(ltcr equivalellt).

Source: National Weather Service Forecast omce, Lli Crosse, Wisco!1~il1 (www.crh.tloaa.go"hm:/clirn(lh':)

T = Trace «0.0 I" prcJ;ipitlllion)

Sn = Snow

Page50f 5

TABLES Changes in Chemical-Specific Standards

Shaw Avenue Dump Site Charles City, Iowa

Contaminant'

Arsenic III

Media

Surface Water

Cleanup Level (llg/L)

100

Standard

Previous 200 (chronic) 360(acute)

150 (chronic) New 340 (acute)

CitationNear

EPAl1980

lAC 20072

Notes:

1. The 1985 Consent Order addresses total arsenic 2. Chapter 61 (Water Quality Standards) Iowa Administrative Code (lAC)

TABLE 9 Changes in Federal MCLs Shaw Avenue DUll1p Site

Charles City, Iowa

Potential Contaminant of Cuncel'll 2000 ROD Current ~g/L ~g/L

Vinyl chloride 2 2 I,l-Dichloroethene 7 7 1,2-Dichloroethane 5 5

1,I ,2-Trichlorocthane - 5 Benzene 5 5 Toluene 1,000 1,000 Xylenes 10,000 10,000

2-N itroani line - -

Arsenic 50 10 Cadmium 5 5

Manganese - -

Notes:

~lg/L - micrograms per liter ROD - Record of Decision

TABLEJO Changes in Iowa Action Levels

Shaw Avenne Dnmp Site Charles City, Iowa

Potential Conlaminant of Concel'll 2000 ROD Cnrrent

Ilg/L Ilg/L Vinyl chloride 0.015 0.02

I,I -Dichloroclhcnc 7 0.06 1,2-Dichloroclhanc 0.4 0.4

I, I ,2-Trichloroclhanc 3 0.6 Benzene I I Toluene 1,000 1,000 Xylenes 10,000 10,000

2-Nilroanilinc - -Arsenic 0.03 0.02

Cadmium 5 5 Manganese - 300

Notes:

pg/L - micrograms per liter ROD - Record of Decision

TABLE 11 COl1lllarison of Oral Reference Doses

Shaw Avenue DUI1I11 Site Charles City, Iowa

PCOC 2005 RfD Current RfD Effect on Risk mg/l<g/dal' mg/kg/dal'

Vinyl chloride NA 3.0xI0~' Increased ri sk I , I -Diehloroethene 9.0x I O~ J 5.0x I O~ ' Decreased risk 1,2-Diehloroethanc NA 2.0x I O~ ' Increased risk

I, I ,2-Triehloroethane 4.0x I O~ ' 4.0xI0·· No change Benzene NA 4.0xlO·' Increased risk Toluene 2.0x I0·' 8.0x 10" Increased risk Xylenes 2.0 2.0xJO~ Increased risk

2-Nitroaniline 6.0x I O~ ' l.Ox JO~' Decreased risk Arsenic 3.0x I O~ 3.0x JO~ No change

Cadmiulll 5.0x I O~ ' 5.0x I O~' No change Manganese 4.7xI0~ ' 2.4x JO~' In creased risk

Notes:

peac - potential contaminant of concern BLRA - baseline risk assessment mg/kglday - milligram pel' kilogram pCI' day NA - not applicable

TABLE 12 COlllparison of Inhalation Refel'ence Concentrations

Shaw Avenue DUllIp Site Charles City, Iowa

PCDC 2005 RfC Cu ....eul RfC Effecl 011 Risl< IIIg/lll' IIIg/lll'

Vinyl chloride NA 1.0x10· Increased risk I,I-Dichloroclhelle 3.2x 10" 2.0xI0· Decreased risk 1,2-Diehloroelhane NA 2.4 Increased risk

1,1,2-Trichloroethane 1.4X I 0" NA Decreased ri sk Benzene NA 3.0xI0·' Increased ri sk Toluene 7.0XIO·' 5.0 Decreased ri sk Xylenes NA LOx 10' Increased ri sk

2-Nitroanilinc 2. IXI0·; 5.0x I 0" Increased ri sk Arsenic 1.1 X10" 1.5x I 0" Increased ri sk

Cadmiulll 1.8X I 0" LOx I 0" Increased ri sk Manganese 1.6X 10" 5.0xlO·' Increased ri sk

Notes:

PCOC - potential contaminant of concern BLRA - baseline risk assessment I11ghnJ - milligram per cubic meter NA - 1I0t applicable

TABLE 13 Changes in Oral Cancel' Slope Factors

Shaw Avenue Dump Site Charles City, Iowa

PCOC 200S CSF Curreut CSF Effect on Risl< (mg/l<g/day)"' (mg/l<g/dal')"

Vinyl chloride 1.9 7.2xI0·' Decreased risk I, I-Dichloroethene 6.02xI0·' NA Decreased risk 1,2-Dichloroethane NA 9.lx 10" Increased ri sk

I, I ,2-Trichloroethane 5.7xI0-' 5. 7xI0­ ' No change Benzene 2.9x I 0-' 5.5x I 0-' Increased ri sk Toillene NA NA No change Xylenes NA NA No change

2~NitroaJ1ilil1e NA NA No change Arsenic 1.5 1.5 No change

Cadmium NA NA No change i'vlanganese NA NA No change

Notes:

PCOC - potential contaminant of concern BLRA - baseline risk assessment mg/kglday - milligram pel' kilogmm per day NA - not applicable

TABLE 14 Changes in Cancer Inhalation Unit Risk

Shaw Avenue DUllIp Site Charl es City, Iowa

PCOC 2005 IUR Current IUR Effect 011 Risl, (1I~/nr'r (lIg/lllT'

Vinyl chloride 4.4x I 0­ " 4.4x I0-" No change I,I-Dichloroethelle 1.7xI0· NA Decreased risk 1,2-Dichloroethalle NA 2.6x I0-- Incrcnscd ri sk

I, I ,2-Tri chloroethanc J. 6x I 0" 1. 6X I 0-' No change Benzene 8.3x I 0-0 7.8x I 0-0 Decreased risk Toluene NA NA No change Xylenes NA NA No changc

2-Nitroanilillc NA NA No change Arsenic 4.3x 10" 4.3xI0-' No changc

Cadmium NA J.8x I 0-' Increa sed ri sk Manganese NA NA No change

Notes:

peDe - potential contaminant of concern BLRA - baseline risk assessment

/ ')' " '-'(~lg III - per nllcrogram per Cliule meter NA - not applicable

TABLE 15 Maintenance Items To Be Completed By PRP

Shaw Avenue Dump Site Charles City, Iowa

Issue Recommended

Follow-up Action Party

Responsible Oversight Agency

Milestone Date

Corrective Action/ Completion Date

1. Although securely locked, the well cap for MW-8A co uld be opened without removing the lock.'

Install additional locking clasp on MW-8A to secure the well.

PRP EPA April 2010 Well cap and welded locking cl ips lowered on riser pipe/May 3, 2010

2. MW-4 was missing a mechanical well plug/cap. '

Install new concrete well pad at MW-4B with sufficient slope to discourage entry of surface­water runoff.

PRP EPA April 2010 Lock and torqu able plug installed/April 22,2010

3. At MW-4B the concrete well pad lacked sufficient slope to discourage entry of surface-water ru noff and was cracked around the edQes. '

Install mechanical well plug/cap in MW-4 to discourage entry of surface-water runoff.

PRP EPA June 2010 Replacement cement collar installed/May 5, 2010

4. MW-2 did not have a mechanical well plug/cap to discourage entry of surface­water runoff. '

Install mechanical well plug/cap in MW-2 to discourage entry of surface-water runoff.

PRP EPA April 2010 Lock and torquable plug installed/April 22, 201 0

5. At flush-mounted well MW-18, one of the bolts securing the well cap was missing and the second remaining bolt was loose allowing the lid to be potentially pried off. '

Replace the missing bolt on the locking cap for MW-18 to discourage vandalism and provide a more secure seal.

PRP EPA April 2010

Cap's two bolt receivers in surface casing re-threaded and cap secured/May 3, 2010

6. Based on biennial sampling, arsenic concentrations have increased in MW-2 since 2003.

Increase monitoring frequency for MW-2 from biennial to semi-annual to more closely monitor increasinq arsenic concentrations.

PRP EPA April 2010 Included in semi-annual sampling event performed in April/April 16, 2010

7. MW-14 is obstructed and cannot be sampled without repair or re-<lrilling.'

Visually inspect MW-14 with adown-hole camera to determine nature of obstruction . If obstruction cannot be removed, well should be re-<lrilled since it has historically elevated levels of arsenic.

PRP EPA June 2010

Obstruction identified as a metal split-spoon re mnant. Well/hole over-<lrilled and replaced with a 2-inch diameter well screen to original bottom of 35 It bgs. Survey of new ref. elevation neededlMay 5, 2010

8. MW-18 is an open-borehole completion. Collapse of the borehole wa ll prevents

Visually inspect MW-18 with adown-hole camera to determine nature of obstruction. If obstruction

PRP EPA June 2010 Limestone obstruction removed bLd ri ll~g , .

Page 1 of 2

Issue

water-level collection.'

9. Six wells: MW-2, MW-2A, MW-4, MW-4A, MW-4B, and MW-14 were recen~y converted from aboveilround well completions to flush-mount well completions. These wells had not been re­surveyed at the time of the site inspection. Therefore, water levels collected from these wells cannot be used to determine the groundwater flow direction, until the reference elevations have been established .

Recommended Follow-up Action

cannot be removed, consider abandoning since the well is only used to collect water levels.

Wells MW-2, MW-2A, MW-4, MW-4A, MW-4B, and MW-14 should be re-surveyed as soon as possible so water levels collected from these wells can be used to determine the groundwater flow direction.

Party Responsible

PRP

Oversight Agency

EPA

Milestone Date

July 201 0

Corrective Actionl Completion Date

Corehole opened to original bottom at 42.5 It bgs/May 4, 2010

Notes:

I - Identified during March 10. 2010. site insJXX=tion PRP - Potentially Responsible Party

Page 2 of2

,

FIGURES

"..,"' ..,/8'\\~ , .,.. :..""~,,

N

Figure 1 Location Map Shaw Avenue Dump Site

Des Moines

. J.,.---0---1 125 250 Miles

~ 1

DRAWN BY: ASG

DATE: March 2010 ~ us Army Corps of Engineers •

.1'''.'''~'. Ii?i':iI . ft , DRAWN BY: ASG Figure 2 Site Map ~\~ , US Atmy COI'p$DATE: March 2010 -.7 Shaw Avenue Dump Site CHECKED BY: FWM ot Englroeoors .

o • • o

LEGEND

Approximate Site Boundary as Defined in OU2 ROD

Stream Gauging Station

Groundwater Monitoring Well

345 690 Feet N

A

,".""/1-;. ; .". ; DRAWN BY: ASG Figure 3 Groundwater Flow - October 2009 ~ '~ , ",,_c..,.Shaw Avenue Dump Site DATE: March 2010 CHECKED BY: FWM \"-'''' ~- .

LEGEND

• Monitoring Well

• Stream Gauging Station

October 2009 - Potentiometric Contour ~ Groundwater

Flow Directon N o 155 310 Feet

! ! I I A

FIGURE 4 Arsenic Concentrations MW-2

Shaw Avenue Dump Site

1200

1000 +I----------------------------------------------------------------------~

800

~ 3­.:! 600 ;; ~

< 400

_ MW2

--Apparent Concentration Trend

R' =0.9981

200 I ~

o +I-------------,--------------~------------~------------,_------------~ 1/1/2004 1/1/2005 1/1/2006 1/1/2007 1/1/2008

Date

:7 < I

FIGURE 5 Arsenic Concentrations MW-6

Shaw Avenue Dump Site

450 ,

400 I \ J

350 I \ _ Arsenic Concentration (ug/l)

./ \ I --Apparent Concentration Trend I

3001~ ..........., ~ .

~ 250 R'= 0.4587

-=­.:<

~ 200 ' I -:::::000...", ,<: {r =--- (

150 I \\ r/ l\ -­

100 +1---------------------------------------------------------------------1

50 +1------------------------------------------------------------------;

o ~I------r_----,_----~------r_----,_----~------r_----,_----~------r_----~ 5/1/2004 11 11/2004 51112005 1111/2005 5/1/2006 11 11/2006 51112007 11 11/2007 51112008 1111/2008 511 12009

Date

--

/ \ .. ~~

FIGURE 6 Arsenic Concentrations MW-7

Shaw Avenue Dump Site

200.0 .-------------------------------------------------------------------------------,

180.0 I 1\ / \.

160.0 I I "

140.0 I I \ ~~ V"

120.0 I I __~ ? ~ 1000 ~ -----= I 1'= . ~....."....... R' = 0.3595

'" ~

.;: 80.0 I:......~~ '. I 1

60.0 I \ I 1

- Arsenic Concentration (ug/l)40.0 I ... I

--Apparent Concentration Trend

20.0 I \ I

0.0 I ,

5/1/2004 1111/2004 51112005 1111/2005 51112006 1111/2006 51112007 1111/2007 51112008 1111/2008 51112009

Date

FIGURE 7 Arsenic Concentrations MW-8

Shaw Avenue Dump Site

3000

2500 I '"

~Arsenic Concentration (ugfl)

--Apparent Concentration Trend 2000 I \ . I I

? ~

-=- ~ I ,.~ 1500............... , , ;; ~

..:­1000

500

R2 = 0.289

o 5/1/2004 1111/2004 51112005 1111/2005 51112006 1111/2006 51112007 1111/2007 51112008 1111/2008 51112009

Date

FIGURE 8 Precipitation Comparison with Groundwater Elevations in the Alluvial

Wells of the Upper Cedar Valley Aquifer Shaw Avenue Dump Site

1005.00 30 25

- 20

1000.00 ~~--11 ~~ ~ \ __ ..... __ \ __ / __ .... __ ..., __ oJ '-..... /\..... "'...... "''''\/ .... _/'\_ ........ '\\/ /_ .... , r..... 1\

J 5 o

~ ~995.00 ~

::3' ~ ~

~ '" <{"" 990.00 .5! -;; ~

Q.~ '0;

~ 985.00 0::'" ",. ~.

" 5 "' :;;:980.00 I •

975.00 " . ~. . ­

970.00 1 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~--\-1­

14-Jan-04 17-Feb-05 24-Mar-06 28-Apr-07 1-Jun-08 6-Jul-09 1 0-Aug-1 0

~-MW1A • MW-1B MW-2A MW-3A

• MW-4A -+- MW-4B • MW-6A MW-8A

.. MW-12A ------ MW -15A - x­ MW-15B - - - Monthly Precipitation

FIGURE 9 Precipitation Comparison with Groundwater Elevations in the Bedrock

Wells of the Upper Cedar Valley Aquifer Shaw Avenue Dump Site

1005 ,-------------------------------------------------------------------------, 30 25 20 15

1000 10 J / \ \ -/' ",. -, __ ....... __ / -,- - / ­ 5

/ \_- .... ----" ~ \ o - ~--""---t \ -- "A ------ v

~

' , !! ~

0:;:3' :§.00 ~ 995 1 .... ­ /v:~ ~"::__----------- .

.§\«"" 990 - -.':,- / / <-"'.,0; :E

'c,~ '0:;:i. \

- ~ / / ,

\ d .~ 985 ,;:; " <; -\ ~ !.i os: __ -~T-- '\ ~~_ ~

­~-?_:...---.~ j IlL __ :---- . \ ~_'?-­ .=:-.G - - - .....= .. ~ !' • ! , . _ .., '_

t:;i e-.___ ... ~ I .'.. ~ • -§ ;;980 1!-- ­

- .. -" . ;, '"' -~ . -. " . , " ~ 'A . . "',~~ ."- .

~ ~•il_~ --- ~ . l' l::

975

970 L! ______-,____________________-,______-,______~

14-Jan-04 17-Feb-05 24-Mar-06 28-Apr-07 1-Jun-08 6-Jul-09 1 0-Aug-1 0

--MW-1 --MW-2 • MW-3 MW-4 MW-6 • MW-7 + - MW-8 • MW-9 MW-10 • MW-11 • MW-12 x MW-13

___ MW-16lI( MW-15 MW-17 --MW-18 l--MW-19 · MonthlyPrecipitation _ _____._________ _ _~

ATT ACHMENTS

ATTACHMENT 1

Public Notice

U.S. Environmental Protection Agency (EPA) Region 7 and

Iowa Department of Natural Resources (IDNR) to conduct

Second Five·Year Review for the Shaw Avenue Dump Site

Charles City, Iowa

EPA and IDNR have begun the second Five·Year Review at the Shaw Avenue Dump Site. The review is required by the Superfund law to make sure the cleanup continues to protect human health and the environment.

The Administrative Record is available at the following locations during normal business hours:

Charles City Public Library EPA Region 7 Records Center 106 Milwaukee 901 North Fifth Street Charles City, Iowa Kansas City, Kansas

Questions or requests for information can be submitted to:

Fritz Hirter Community Involvement Coordinator

U.S. EPA Region 7 901 North Fifth Street

Kansas City, Kansas 66101 Toll Free: (800) 223-0425

e-mail: hirter.fritz@epa.gov

ATTACHMENT 2

Site Inspection Checldist

Site Inspection Checldist

I. SITE INFORMATION

Site name: Shaw Avenue Dump Site Date of inspection: March 10,2010

Location and Region: Charles City, Iowa/ Region 7 EPA 10: IAD980630560

Agency, office, or company leading the five-yeoI' l'eview: U.S. EPA Region 7

\Vea ther/temperature: Rain and moderately heavy fog/39"P

Remedy Includes: (Check all that apply) o Landfill cover/containment o Monitored natural attenuation o Access controls o Groundwater containment x Institutional controls o Vertical barrier walls o Groundwater pump and treatment o Surface water collection and treatment x Other: Groundwater Monitoring

Attachments: x Inspection team roster attached o Site map attached

II. INTERVIEWS (Check all that apply)

I. O&M Site Manage,' Name: Neil Leipzig Title: Project Manager Date: March 10, 20 I 0

Interviewed: x at site 0 at office 0 by phone Phone no. Problems, suggestions; D Report attached: No problems or suggestions were provided. Mr. Leipzig indicated that the remedy was functioning as expected and, based on data obtained from MW·6 and M\V·S, contaminant levels were decreasing.

2. EPA Remedinl PI'oject Mn"agel' Name: Shelley Brodie Title: EPA RPM Date: March 10, 20 I 0

Interviewed: x at site 0 at office 0 by phone Phone no. Problems, suggestions; D Report attached: No problems or suggestions were provided. Ms. Brodie statcd that she had bcen well informed about the site's activities and progress and that she was technically impressed and that the work had been done diligcntly.

Site Inspcction Checklist Page) or 14

3. Localrcgulatol'Y authorities and response agencies (Le., State and Tribal offices, emergency response office, police department, office of public health or environmental health, zoning office, recorder of deeds, or other city and county offices, etc.) Fill in all that apply.

Agency: City of Charles City, Iowa Contact: Tom Brownlow City Administrator March 10,2010

Name Title Date Interviewed: x at site 0 at office 0 by phone Phone no. Problems; suggestions; 0 Report attached: No problems were identified. Mr. Brownlow suggested that it would be nice to save money on groundwater monitoring but that the city (as a PRP) would do what it had to do. Mr. Brownlow felt that he had been well informed about the site's activities and progress.

Agency: City of Charles City. Iowa Contact: Tracy Meise PlaiUling and Project Supervisor March 10, 2010

Name Title Date Interviewed: x at site 0 at ofi1ce 0 by phone Phone no. Problems; suggestions; 0 Report attached: No problems were identified. Ms. Meise indicated that it would be nice to not pay monitoring costs given that fact that the levcls of contaminants arc low. Ms. Meise felt that she had been well informed about the site ' s activities and progress.

Agency: Iowa Department of Natural Resources Contact: Robert Dnlstrup Environmental Engineer March 11,2010

Name Title Date Interviewed: x at site 0 at office 0 by phone Phone no. Problems; suggestions; 0 Report attached: No problems were identified. Mr. Dmslmp stated that the he was not in favor of monitoring weJlsjust for the sake of monitoring, and that if the site were not a Superfund site, the state oflowa would nol spend money sampling. He also indicated that the majority of money spent on sampling should be directed to sampling the Cedar River since this is where the contaminants end up.

Agency: Iowa Department of Natural Resources Contact: Cal Lundberg Environmental Program Supervisor March 11,2010

Name Title Date Interviewed: x at site 0 at ofi1ce 0 by phone Phone no. Problems; suggestions; 0 Rcport attached: No problcms or suggestions were provided.

4. Other interviews (optional) 0 Report attached.

Site Inspection Checklist Page 2 of 14

III. ON-SITE DOCUMENTS & RECORDS VERIFIED (Cheek alilhat apply)

I. O&M Documents x O&M Illanllal x Readily avai lab le x Up to date ON/A o As-built drawings o Readily available o Up to date x N/A D Maintenance logs o Readily available o Up to date x N/A Remarks

2. Site-Specific HeAlth and SAfety PIAn o Readily available o Up 10 date x N/A o Contingency plan/emergency response plan o Readily available o Up to date x N/A Remarks

3. O&M and OSHA Training Records o Readily available o Up to dale x N/A Remarks

4. Permits and Service Agreements o Air discharge pennit o Readily available o Up to date x N/A o Effluenl discharge o Readily available o Up to date x N/A o Waste disposal, POTW o Readily available o Up 10 date x N/A o Other permits o Readily available o Up 10 date x N/A Remarks

5. Gas Generation Records o Readily available o Up to date x N/A Remarks

6. Settlement Monument Records o Readily available o Up to dale x N/A Remarks

7. Groundwater Monitoring Records x Readily available x Up to date ON/A Remarks

8. Leachate Extraction Records o Readily available o Up 10 date x N/A Remarks

9. Discharge Compliance Records OAir o Readily aVAilable o Up to date x N/A o WaleI' (effluent) o Readily available o Up to date x N/A Remarks

10. Daily Access/Security Logs o Readily available o Up 10 date x N/A Remarks

Site Inspection Checklist Page 3 of 14

IV. O&M COSTS

I. O&M Organization o State in-house o Contractor for Slate o PRP in-house x Contractor for PRP o Federal Facility in-house o Contractor for Federal Facility o Other

2. O&M Cost Reeol'ds x Readily available x Up to date o Funding mechanism/agreement in place Original O&M cost estimate: Unknown o Breakdown attached

Total allnual cost by year for review period if available

From: 12/27/04 To: 12 /25105 S25,649.82 o Breakdown attached Date Date Total cost

From: 12/26/05 To: 12/31106 S17,656.19 o Breakdown attached Date Date Total cost

From: 01101107 To: 12/30107 S18, 165.42 o Breakdown attached Date Date Total cost

From: 01101108 To: 12/28/08 S25,938.39 o Breakdown attached Dale Date Total cost

From: 12 /29/08 To: 12/27/09 S22,973.56 o Breakdown attached Date Date Total cost

3. Unanticipated 01' Unusually High O&M Costs During Review Period Describe costs and reasons: None

V. ACCESS AND INSTITUTIONAL CONTROLS x Applicable D N/A

A. Fencing

I. Fencing dAmnged o Location shown 011 site map o Gates sec ured x N/A Remarks

D. Othel' Access Restrictions

I. Signs and other security measures o Location shown on site map x N/A Remarks

Site Inspection Checklist Page 4 of 14

C. Institutioual Controls (ICs)

I. Implementation and enfol'cement Site conditions imply les not properly implemented DYes x No ON/A Site conditions imply les not being fully enforced DYes x No ON/A

Type of monitoring (e.g., self-reporting, drive by); Sclf- reporting (site insQcction reports) Frequency: Quarterly Responsible party/agency: Conestoga-Rovers & Associates (PRP contractor) Contact: Neil Leipzig Project Manager Quarterly 262-945-0626

Name Title Datc Phone no.

Reporting is up-la-date x Yes ONo o N/A Reports are verified by the lead agency DYes x No ON/A

Specific requirements in deed or decision doclIments have been met x Yes ONo ON/A Violations have been reported DYes ONo x N/A Other problems or suggestions: o Report attached

2. Adequacy x les arc adequate Dies are inadequate ON/A Remarks

D. General

I. Vandalism/ trespassing x Location shown on site map (MW-I3) o No vandalism evident Remarks: The lock on M\V-13 had been cut off purportedly by parties investigating contamination associated with petroleum storage tanks at the gas station fonnerly located ncar the intersection of Shaw Avenuc and Clark Strect. A tamper-resistant lock was placed on the well by the PRP contractor.

2. Land lise changes 011 site x N/A Remarks

3. Land lise changes off site x N/A Remarks

VI. GENERAL SITE CONDITIONS

A. Roads x Applicable ON/A

I. Roads damaged o Location shown on site map x Roads adequate ON/A Remarks

Site Inspection Checklist Page 5 of 14

B. Other Site Conditions

Remarks

A. Landfill Snrface

VII. LANDFILL COVERS D Applicable x N/A

I. Settlement (Low spots) o Location shown on site map o Settlement not evident Areal extent Depth

Remarks

2. Cracks o Location shown on site map o Cracking not evident Lengths Widths Depths

Remarks

3. Erosion o Location shown on site map o Erosion not evident Areal extent Depth Remarks

4. Holes o Location shown on site Illap o Holes not evident Area l extent Depth Remarks

5. Vegetative Cover D Grass D Cover properly established o No signs of stress G Trees/Shrubs (indicate size and locations 011 a diagram) Remarks

6. Alte)'native Covel' (armored rock, concrete, etc.) D N/A Remarks

7. Bnlges o Locat ion shown on site map D Bulges not evident Areal extent Height Remark s

8. Wet Areas/Wat... Damage o Wet areas/water damage not evident o Wet areas o Location shown on site map Areal extent D Ponding o Locttlion shown 011 site map Areal extent D Seeps o Location shown on site map Areal extent D son snbgrade o Location shown 011 site map Areal extent Remarks

Site Jnspection Checklist Page 6 of 14

9. Slope Instabilit), o Slides o Location shown on site map o No evidence of slope instability Areal extent Remarks

B. Benches o Applicable x N/A (Horizontally constructed mounds of earth placed across a steep landfill side slope to interrupt the slope in order to slow down the velocity of surface runoff and intercept and convey Ihe runofr to a lined c1mnnel.)

I. Flows Bypass Bench o Location shown on site map o N/A or okay Remarks

2. Benell Dreached o Location shown on site map o N/A or okay Remarks

3. Delich Overtopped o Location shown 011 site map o N/A or okay Remarks

C. Letdown Channels o Applicable x N/A (Channellincd with erosion co ntrol mats, rip-rap, grout bags, or gabions that descend down the steep side slope of the cover and will allow the mnoffwater collected by the benches to 1110ve off orthe landfill cover without creating erosion gullieso)

I. Settlement o Location shown on si te map 0 No evidence of settlement Areal extent Depth Remarks

2. Material Degloadatioll o Location shown 011 site map 0 No evidence of degradation Material type Areal extent Remarks

3. Erosion o Location shown on site map 0 No evidence of erosion Areal extent Depth Remarks

Site Inspection Checklist Page 7 of 14

4. Undercutting o Location shown on site map o No evidence of undercutting Areal extent Depth Remarks

5. Obstrllctions Type o !'Jo obstmctions o Location shown on site map Areal extent Size Remarks

6. Excessive Vegetative Growth Type o No evidence of excessive growth 0 Vegetation in channels does not obstruct flow 0 Location shown on site map Areal extent Remarks

D. Covel' Penetrations o Applicable x N/A

I. Gas Vents o Active o Pa ssive o Properly secured/locked o Functioning o Routinely sampled o Good condition o Evidence of leakage at penetration o Needs Maintenance ON/A Remarks

2. Gos Monitoring Probes o Properly secured/locked o Functioning o Routinely sampled o Good condition o Evidence of leakage at penetration o Needs Maintenance ON/A Remarks

3. Monitoring Wells (within smeace area of landfill) o Properly secured/locked o Functioning o Routinely sampled o Good condition o Evidence of leakage at penetration D Nceds Maintenance ON/A

Remarks

4. Leachate Extraction \Vells o Properly secured/locked o Functioning D Routinely sampled o Good condition o Evidence of leakage at penetration o Needs Maintenance ON/A Rcmarks

5. Settlement Monuments o Located o Routinely surveyed ON/A Remarks

Site Inspection Checklist Page 8 of 14

E. Gas Collection and Treatment o Applicable x N/A

1. Gas Treatment Facilities o Flaring o Thermal deSlmctioli o Collection for rellse o Good condition o Needs Maintenance Remarks

2. Gns Collection Wells, Mnnifolds and Piping o Good cond ition o Needs Maintenance Remarks

3. Gas Monitoring Facilities (e,g., gas monitoring of adjacent homes or buildings) o Good condi tion o Needs Maintenance D N/A Remarks

F. Covel' Drainage Layer o Applicable x N/A

1. Outlet Pipes Inspected o Functioning D N/A Remarks

2. Outlet Rock Inspected o Functioning D N/A Remarks

G. Detention/Sedimentation Ponds o Applicable x N/A

1. Siltation Area l extent Depth o N/A o Siltation not evident Remarks

2. Erosion Areal extent Depth o Erosion not evident Remarks

3. Outlet Works o Functioning D N/A Remarks

4. Dam o Functioning o N/A Remarks

Site Inspection Checklist Page 9 of 14

H. Retaining Walls o Applicable x N/A

I. Deformations o Location shown on site map o Deformation not ev ident Horizontal di sp lacement Vertical displacement Rotational displacement Remarks

2. Degl'adation o Location shown on site map o Degradation not evident Remarks

I. Perimeter Ditches/Off-Site Discharge o Applicable x N/A

I. Siltation Areal extent

o Location shown on site map Deplh

o Siltation 110t evident

Remarks

2. Vegetative G.'owth o Location shown on site map ON/A o Vegetation does not impede flow Areal extent Type Remarks

3. El'oslon Areal extent

o Location shown on site Illap Deplh

o Erosion not evident

Remarks

4. Discharge Structure o Functioning ON/A Remarks

VIII. VERTICAL BARRIER WALLS o Applicable x N/A

I. Settlement Areal extent

o Location shown all site Illap Deplh

o Settlement not evident

Remarks

2. PerformAnce i\'lonitoring Type of monitoring: D Performance not monitored Frequency o Evidence of breaching Head differenlial Remarks

Site Inspection Checklist Page 10 0f l4

IX. G ROUNDWATER/SURFACE WATER REMEDIES x Applicable D N/A

A. Groundwater Extraction 'Veils, Pumps, and Pipelines D Applicable x N/A

I. PumllS, \Vellhend Plumbing, and Electrical o Good condition D All rcqui red wells properly operating D Needs MaintclHlIlce 0 NIA Remarks

2. Extraction System Pil)clincs, Valves, Valve Boxes, and Other Appurtenances o Good condition o Needs Maintenance Remarks

3. Spare Parts and Equipment D Readily available D Good condit ion D Requires upgrade D Needs to be provided Remarks

B. Surface \Vatel' CoUection Structurcs, Pumps, and Pipelines D Applicable x N/A

I. Collection Structures, Pumps, and Electrical o Good condition o Needs Maintcnance Remarks

2. Surface 'Vntcr Collection System Pipelines, Valves, Valve Boxes, nnd Other Appurtenances D Good condition o Needs Maintenance Remarks

3. Spare Parts and Equipment D Readily available D Good condition D Requires upgrade D Needs to be provided Remarks

C. Treatment System D Applicable x N/A

I. Trcatment Train (Check componcnts that apply) o Metals removal o Oil/water separation o Bioremcdiation D Air stripping D Carbon adsorbcrs D Filters D Additive (e.g., chelation agent , flocculent) D Others D Good condit ion o Nceds Maintenance o Sampling ports properly marked and functional o Sampling/maintenance log displayed and up to date D Equipment properly identified o Quantity of groundwater treated annually o Quantity ofsurfhce water treated annually Remarks

Site Inspection Checklist Page II or 14

2. Electrical Enclosures and Panels (properly rated and fUllctional) D N/A o Good condition o Needs Mai ntenance Remarks

3. Tanks, Vaults, StOl'age Vessels D N/A o Good condition o Proper secondary containment o Needs Maintenance Remarks

4. Dischnrge Structure and AIJpurtcnRnces D N/A o Good condition o Needs Ma intenance Remarks

5. Treatment Building(s) D N/A o Good condition (esp. roof and doorways) o Needs repair o Chemi ca ls and equipment properly stored Remarks

6. Monitoring 'Vells (pump and treatment remedy) o Properly securedllocked o Functioning o Routinely sampled o Good condition o All required wells located o Needs Maintenance D N/A Remarks

D. Monitol'ing Data

I. Monitoring Data x Is routinely submitted on time x Is of acceptable quality

2. Monitoring data suggests: o Ground water plume is cflectively contained x Contaminant concentrations are declining

E. Monitored Natural Attenuation

I. Monitoring 'Veils (natura l attenuation remedy) o Properl y secured/locked D Functioning o Routinely sampled o Good condition o All required well s located D Needs Maintenance x N/A Remarks

X. OTHER REMEDIES

If there are remedies applied at the site whi ch are not covered above, attach an inspection sheet describing the physical nature and condi ti on of any facility associa ted with the remedy. An ex.ample would be soil vapor ex. trac tion,

Site Inspection Checklist Page 12 of 14

XI. OVERALL OBSERVATIONS

A. Implementation of the Remedy

Describe issues and observations relating to whether the remedy is effective and fUTlctioning as designed. Begin with a brief statement of what the remedy is to accomplish (i.e., to contain contaminant plume, minimize infiltration and gas emission, etc.).

The remedy consists of excavation, treatment, and disposal of contaminated soils at an offsite RCRA~ permitted landfill, as well as groundwater monitoring and monitoring orthe Cedar River. The remedy has been shown to be effecti ve. Groundwater monitoring and monitoring in the Cedar River has continued and impacted source area wells show decreasing trends.

B. Adequacy or O&M

Describe issues and observations related to the implcmentation and scope ofO&M procedures. In particular, discuss their relationship to the current and long-term protectiveness of the remedy.

O&M consists of quarterly inspections and reporting on site conditions, and monitoring and evaluation of groundwater and surface watcr data. O&M procedures have been properly implemented and arc being sufficiently maintained to ensure current and long-tcrm protectiveness of the remedy.

C. Early Indicators of Potential Remedy Problems

Dcscribe issues and observations sllch as unexpected changes in the cost or scope of O&M or a high frequency of unscheduled repairs, that suggest that the protectiveness of the remedy may be compromised in the future.

The March 10,2010, site inspection and a review of site documentation did not reveal any issues that would indicate there are potential problems with thc remedy. A number of issues were identified involving monitoring wells (installing additional well clasp, installing new concrete pad, and installing mechanical well plug/cap), they are considered a part of routine operations and maintenance activities at the site. The frequency of repairs of this nature has not been high nor are they expected to be high in the future.

D. OPI}Ortuliities for Optimization

Describe possible opportunities for optimization in monitoring tasks or the operation of the remedy.

A reduced sampling frequency for groundwater monitoring wells and surface-water monitoring should be explored. Requests for optimization (revised sampling and analysis schedule, among others) should include the basis for the request and sufficient documentation to support the request and ensure the protectiveness of the remedy.

Site Inspection Checklist Page 130fl4

Site Inspection Team Roster

Persollnel Representin g Phone Number

Shelley Brodie EPA Region 7 913-551-7706

Andy Gosnell U.S. Army Corps of Engineers, Kansas City

District 816-389-3891

Fred Molloy U.S. Army Corps of Engineers. Kansas City

District 816-389-3499

Neil Leipzig Conestoga-Rovers & Associates 262-945-0626

Tom Brownlow city of Charles City. Iowa 641-257-6309

Tracy Meise city ofCh.rlcs City. Iowa 641-257-6309

Site Inspection Checklist Page 140f 14

ATTACHMENT 3

Photographs Documenting Site Conditions

Photo 1: Well Cluster Adjacent to Former Contaminant Source Including Wells MW-S, MW-SA and MW-19.

Photo 2: Monitoring Well MW-IO in Standing Water.

Photo 3: Mulch Stockpiles on Charles City Property.

Photo 4: MW-IS Well Cluster Showing Mu1ch Stockpile in Background.

Photo 5: Construction and Demolition Debris Stored on Charles City Property.

Photo 6: Cedar River Gauging Station # 12 Located on Southern Boundary of the Shaw Avenue Site on Charles City Property.

Photo 7: Cracked Well Pad Surrounding the Flush-Mounted Monitoring Well MW-4B.

ATTACHMENT 4

List of Documents Reviewed

List of Documents Reviewed

Agency for Toxic Substances and Disease Registry. Minimal Risk Levels (MRLs) for Hazardous Substances. Available on the Web at http://IVIVIV.atsdr.cdc .gov/mrls/.

B&V Waste Science and Technology Corporation (BVWST), 1998. Risk Assessment Addendum Report to Baseline Risk Assessment. Shaw Avenue Site, Charles City, Iowa. October.

California Office of Environmental Health Hazard Assessment. Toxicity Criteria Database. Available on the Web at ht tp: // \ VIV\\'. oeha.ea . gov / risk! chem i ea I D B/ / i ndcx .asp.

Conestoga-Rovers & Associates, 1993. Remedial Action Report, Shaw Avenue Site, Charles City, Iowa. October.

Conestoga-Rovers & Associates, 2000. Feasibility Study Addendum No. I Report. Shaw Avenue Site, Charles City, Iowa. Febl'l\ary.

Conestoga-Rovers & Associates, 2002. Revised Site Monitoring and Maintenance Plan. Shaw Avenue Site, Charles City, Iowa. May.

Conestoga-Rovers & Associates, 2004. Summary of Groundwater Monitoring Results 1992-2004, Shaw Avenue Dump Site, Charles City, Iowa. May.

Conestoga-Rovers & Associates, 2005. Semi-annual Inspection Report, Shaw Avenue Dump Site, Charles City, Iowa. ApriVOctober.

Conestoga-Rovers & Associates, 2006. Semi-annual Inspection Report, Shaw Avenue Dump Site, Charles City, Iowa. ApriVOctober.

Conestoga-Rovers & Associates, 2007. Semi-annual hlspection Report, Shaw Avenue Dump Site, Charles City, Iowa. ApriVOctober.

Conestoga-Rovers & Associates, 2008. Semi-annual Inspection Report, Shaw Avenue Dump Site, Charles City, Iowa. May/October.

Conestoga-Rovers & Associates, 2009. Semi-annual hlspection Report, Shaw Avenue Dump Site, Charles Ci ty, Iowa. April/October.

Conestoga-Rovers & Associates, 2009. Summary of Groundwater Monitoring Results 2003-2009, Shaw Avenue Dump Site, Charles City, Iowa. October.

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Iowa Administrative Bulletin, 2007. Environmental Protection Commission Amendment to Chapter 61 "Water Quality Standards." October.

Iowa Administrative Code, 2010. Chapter 61 Water Quality Standards. January.

Iowa Department of Natural Resources, 2006. Warm Water Stream Use Assessment and Attainability Analysis Protocol. Water Resources Section. March.

Iowa Department of Natural Resources Contaminated Sites. Available on the Web at 11 t t p:1 II VWII' . iolVacln r. govIla ndlcons i t es/h IVregi st ry/hlVs itesa I p ha .11 tm I.

U.S. Environmental Protection Agency, 1985. Concurrence for Issuance ofa CERCLA §106 Order and RCRA §30 13 Order on Consent for the Labounty site, Charles City, IOlVa. April.

U.S. Environmental Protection Agency, 1988. State Water Quality Standards Summary: IOlVa. EPAl440/5-88/047. September.

U.S. Environmental Protection Agency, 1991. Record of Decision, Shaw Avenue Dump, Charles City, IOlVa. September.

U.S . Environmental Protection Agency, 1992. Explanation of Significant Differences, Shaw Avenue Dump, Charles City, Iowa. March.

U.S. Environmental Protection Agency, 1992. Consent Decree, U.S. v. Solvay Animal Health, Inc., and the City of Charles City, Iowa. May.

U.S. Environmental Protection Agency, 2000. EPA Superfund: Record of Decision, Shaw Avenue Site, Charles City, Iowa, OU 02, EPA 10: IAD980630560. EPAlROD/R07-00/031. September.

U.S . EnvirOlunental Protection Agency, 2001. Preliminary Closeout Report, Shaw Avenue Dump Site, Charles City, Iowa. January.

U.S . EnvirolUnental Protection Agency, 2001. Comprehensive Five-Year Review Guidance, EPA/540-R-OI-007. Office of Emergency and Remedial Response. June.

U.S. EnvirolUnental Protection Agency, 2004. Region 9 PRG Table. On the Web at IVIV\\'.epa. gov Iregio n9Is ullerl'u nd/prglfi Ies/04p rgtn b Ie . pd f

U.S. Environmental Protection Agency, 2005. Five-Year Review Report for LaBounty Superfund Site, Charles City, Iowa. September.

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U.S. Environmental Protection Agency, 2005. Five-Year Review Report for Shaw Avenue Superfund Site, Charles City, Iowa. September.

U.S. Environmental Protection Agency, 2009. Risk Assessment Guidance for Superfund, Volume I: Human Health Evaluation Manual (Part F, Supplemental Guidance for Inhalation Risk Assessment). Final. EPA-S40-R-070-002. Office of Superfund Remediation and Technology Innovation. January.

U.S. Environmental Protection Agency, 2009. 2009 Edition of the Drinking Water Standards and Health Advisories. EPA-S40-R-09-011. Office of Water. October.

U.S. Environmental Protection Agency, 2009. Regional Screening Level (RSL) Master Table. December. On the Web at http://lVlVlV.epa.govlreg3 111vmdlrisklhumanlrb­concentra ti on tab le/Generic Tab lcsli ndex. htm.

U.S. Environmental Protection Agency, 2010. National Reconunended Water Quality Criteria. Available on the Web at http://IVIVIv. epa. gOYIIVatersci encelcri teria/lVg ctab Ie/.

U.S. Envirorunental Protection Agency, 2010. Drinking Water Contaminants. Available on the Web at http://lVwlV.epa.gov/safelVater/contami nants/index.html.

U.S. Environmental Protection Agency. Integrated Risk Information System (IRIS). Available on the Web at http://lVlVlV.cpa.govli ri s

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