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EVALUATION OF SELECTED HEAVY METAL CONCENTRATIONSIN SOILS OF AN URBAN STORMWATER RETENTION BASIN
By
MARK S. LANDER
A THESIS PRESENTED TO THE GRADUATE SCHOOLOF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OFMASTER OF SCIENCE
UNIVERSITY OF FLORIDA
2003
Copyright 2003
by
Mark S. Lander
This project is dedicated to my parents Donald W. Lander, and Betty M. Lander. Yoursupport has given me the ability to finish what I have started.
iv
ACKNOWLEDGMENTS
I would like to express my deepest appreciation to my wife, Delia, daughter
Caitlin, and son Kyle. This project was made possible with their love, support, and most
of all patience.
A special thank you goes to Larry “Rex” Ellis. His assistance on this project goes
beyond what any normal individual would have contributed. I thank him for being a
great friend.
I would also like to thank my graduate committee: Dr. Ann Wilke, Dr. Randy
Brown, Dr. Richard Schneider, and especially Dr. Mary Collins, committee chair. Their
patience, understanding and insight have greatly influenced the outcome of this work. As
I have now found out, it is not easy raising a family, working 40 hours a week, and
conducting research.
For technical assistance I would like to thank Larry Schwandes, and Tom Lounga,
for their help with laboratory procedures; Tom Seal, from the Department of
Environmental Protection, for valuable documents; Andy Reich and Dr. Stephen Roberts
for their time concerning toxicological interpretations; and my employer, the Alachua
County Health Department, for allowing me the time to complete this degree.
v
TABLE OF CONTENTS
page
ACKNOWLEDGMENTS ................................................................................................. iv
LIST OF TABLES........................................................................................................... viii
LIST OF FIGURES ........................................................................................................... ix
INTRODUCTION ...............................................................................................................1
Urban Stormwater Runoff............................................................................................... 1Florida’s Stormwater Management Program.................................................................. 2Stormwater Management Systems.................................................................................. 4Deficiencies in Stormwater Regulation .......................................................................... 4Research Site................................................................................................................... 5Overall Research Objectives........................................................................................... 7
LITERATURE REVIEW ....................................................................................................8
Characteristics of Urban Stormwater Runoff ................................................................. 8Methods of Stormwater Management Control ............................................................... 9Evolution of the Florida Urban Non-Point Source (NPS) Management Program........ 12Regulation of Stormwater in Alachua County.............................................................. 15
Local Governmental Regulations ......................................................................... 15Water Management Districts ................................................................................ 16
Pre-Stormwater Retention Basin Soil Quality .............................................................. 20Permitting of the Retention Basin at the NATL ........................................................... 24Review of Past Stormwater Management Studies In Florida ....................................... 25Criteria Used in Metal Contamination Analysis........................................................... 27
Chapter 62.777 F.A.C. – Contaminant Cleanup Target Levels ................................ 27Soil Quality Assessment Guidelines (SQAGs)......................................................... 29Baseline Concentrations for Trace Metals in Florida Soils ...................................... 30
Metals............................................................................................................................ 31Cadmium (Cd) .......................................................................................................... 32Chromium (Cr).......................................................................................................... 33Copper (Cu) .............................................................................................................. 34Lead (Pb)................................................................................................................... 35Nickel (Ni) ................................................................................................................ 36Zinc (Zn) ................................................................................................................... 37
vi
Metal Attenuation in Stormwater retention Basin Sediments....................................... 38
OBJECTIVES....................................................................................................................41
Objective 1 – Evaluation of Current Soil Conditions for Future Studies ..................... 42Objective 2 – Comparison of Current Metal Concentrations in Basin Soils to Soil Target Cleanup Levels ................................................................................................42Objective 3 – Comparison of Current Metal Concentrations in Basin Soils to SoilQuality Assessment Guidelines .................................................................................... 42
MATERIALS AND METHODS.......................................................................................44
Site Description............................................................................................................. 44Sampling Locations ...................................................................................................... 51Field Procedures ........................................................................................................... 57Laboratory Procedures .................................................................................................. 57
Metal Analysis .......................................................................................................... 58Organic Carbon Content ........................................................................................... 58Organic Matter Content ............................................................................................ 59Particle-Size Distribution.......................................................................................... 59pH Analysis............................................................................................................... 59Statistical Methods.................................................................................................... 60
Estimating Metal Loading Rates................................................................................... 60
RESULTS ..........................................................................................................................62
Organic Matter Content ................................................................................................ 63Organic Carbon Content ............................................................................................... 65Soil pH .......................................................................................................................... 65Particle-Size Distribution.............................................................................................. 68Metals: Cadmium.......................................................................................................... 69
Cd vs. Baseline Concentration Levels ...................................................................... 69Cd Concentrations Compared With Various Screening Levels................................ 69
Metals: Chromium (Cr)................................................................................................. 74Cr vs. Baseline Concentration Levels....................................................................... 74Cr Concentrations Compared With Various Screening Levels ................................ 74
Metals: Copper (Cu) ..................................................................................................... 79Cu Vs. Baseline Concentration Levels ..................................................................... 79Cu Concentrations Compared With Various Screening Levels................................ 79
Metals: Lead (Pb).......................................................................................................... 84Pb Vs. Baseline Concentration Levels...................................................................... 84Pb Concentrations Compared With Various Screening Levels ................................ 84
Metals: Nickel (Ni) ....................................................................................................... 88Ni Vs. Baseline Concentration Levels ...................................................................... 88
vii
Ni Concentrations Compared With Various Screening Levels ................................ 88Metals: Zinc (Zn) .......................................................................................................... 92
Zn Vs. Baseline Concentration Levels...................................................................... 92Zn Concentrations Compared With Various Screening Levels................................ 92
Linear Regression Analysis .......................................................................................... 96
DISCUSSION....................................................................................................................97
Simple Linear Regression ........................................................................................... 104Metal Loading Rates ................................................................................................... 106
RECOMMENDATIONS.................................................................................................113
APPENDIXES
A ACRONYM LIST OF AGENCIES AND PROGRAM AREAS .............................. 116
B ADDITIONAL FIGURES..........................................................................................118
C ANALYTICAL RESULTS ........................................................................................124
D REGRESSION ANALYSIS .......................................................................................136
REFERENCES ................................................................................................................141
BIOGRAPHICAL SKETCH ...........................................................................................145
viii
LIST OF TABLES
Table Page
1. Soil clean-up target levels (SCTLs) for contaminated soils .............................................28
2 Soil quality assessment guidelines for heavy metals in study. ..........................................30
3. Baseline concentration for Florida Surface Soils..............................................................31
4. Sample site status for each cell evaluated.........................................................................56
5. Sediment analysis and methods used in study ..................................................................58
6. Metal concentrations in stormwater runoff.......................................................................111
7. L-THIA generated loading rates compared to estimated total mass in SEEP. .................111
A-1. Common acronyms used in this text.............................................................................117
C-1. Particle-size analysis for cell 1 .....................................................................................125
C-2. Particle-size analysis for cell 2 .....................................................................................126
C-3. Particle-size analysis for cell 3 and control site............................................................126
C-4. Laboratory analysis for percent organic carbon (%OC), percent organic matter(%OM), and pH. ...........................................................................................................127
C-5. Metal Concentrations ....................................................................................................129
C-6. Metal concentrations compared to regulatory guidelines. ............................................130
C-7. Regression analysis on all sites, n = 38. .......................................................................132
C-8. Regression analysis on all sites 0 – 5 cm, n = 19..........................................................133
C-9. Regression analysis on all samples, 5 – 10 cm, n = 19.................................................134
C-10. Regression analysis on cell 1, 0 – 5 cm, n = 12 ..........................................................135
ix
LIST OF FIGURES
Figure Page
1. Increased stormwater runoff expectations due to the loss of permeable soil surfaces .....2
2. Current agency infrastructure with respect to stormwater regulations. ............................3
3. Photograph of the stormwater management system at the Natural Area Teaching Lab...6
4. The location of the Stormwater Ecological Enhancement Project (SEEP) ......................17
5. Photograph of four-board fence bordering the eastern and northern region of thestormwater retention basin at the Natural Area Teaching Lab. .......................................20
6. Diagram of stormwater basin............................................................................................21
7. Location of Retention Basin at Natural Area Teaching Lab.............................................44
8. Layout of Natural Area Teaching Lab ..............................................................................45
9. Photograph of stormwater runoff collection area covered with debris.............................46
10. Natural areas and parking surfaces draining to the retention basin.. ..............................47
11. Original design of stormwater retention basin before enhancement project began........49
12. Diagram of the retention basin post enhancement that occurred in 1998.......................50
13. Breakdown of the sample cells inside the stormwater retention basin. ..........................51
14. Location of sample sites in the stormwater retention basin............................................54
15. Sample site locations for the stormwater management system.. ....................................55
16. Percent organic matter in soils within the stormwater retention basin. ..........................64
17. Soil pH at locations within the stormwater retention basin. ...........................................67
18. Cadmium concentrations in the stormwater basin soils..................................................71
x
19. Location of sites where cadmium concentrations were detected above thresholdeffects levels (TELs). .....................................................................................................72
20. Comparison of cadmium concentrations to screening criteria throughout the entirebasin................................................................................................................................73
21. Chromium concentrations in the stormwater retention basin soils. ................................76
22. Location of sites where chromium was detected above contaminant screening levels.. 77
23. Comparison of chromium concentrations to screening criteria throughout the entirebasin................................................................................................................................78
24. Copper concentrations in the stormwater retention basin soils. .....................................81
25. Location of sites where copper was detected above contaminant screening levels........82
26. Comparison of copper concentrations to screening criteria throughout the entirebasin................................................................................................................................83
27. Lead concentrations in the stormwater retention basin soils. .........................................85
28. Location of sites where lead concentrations were detected above threshold effectslevels (TEL’s).................................................................................................................86
29. Comparison of lead concentrations to screening criteria throughout the entire basin. ...87
30. Nickel concentrations in the stormwater retention basin soils........................................89
31. Location of sites where nickel concentrations were detected above threshold effectslevels (TEL’s).................................................................................................................90
32. Comparison of nickel concentrations to screening criteria throughout the entirebasin................................................................................................................................91
33. Zinc concentrations in the stormwater retention basin soil. ...........................................93
34. Location of sites where zinc was detected above contaminant screening levels. ............94
35. Comparison of zinc concentrations to screening criteria throughout the entire basin....95
36. Diagram of the SEEP with areas of concern and short-circuiting path highlighted.. .....100
37. GIS photograph of the area adjacent to the stormwater retention basin .........................107
38. GIS land use classification designations for the areas surrounding the retentionbasin................................................................................................................................108
39. GIS designated land use classes within the retention basin watershed...........................109
xi
40. GIS soils layer added to land use classifications. .........................................................110
B-1. 1988 proposed retention basin with soil boring locations. ...........................................119
B-2. Soil boring locations 1 – 4. Borings conducted in 1988 by Bishop Beville for theUniversity of Florida.....................................................................................................120
B-3. Soil boring locations 5 – 8. Borings conducted in 1988 by Bishop Beville for theUniversity of Florida.....................................................................................................121
B-4. Soil boring locations 9 – 12. Borings conducted in 1988 by Bishop Beville for theUniversity of Florida.....................................................................................................122
B-5. Soil boring location 13. Borings conducted in 1988 by Bishop Beville for theUniversity of Florida.....................................................................................................123
D-1. Regression curve for Cr, Ni, Pb, and Zn; all points observed. ………………………137
D-2. Regression curve for Cr, Ni, Pb, and Zn, with outliers removed……………………. 138
D-3. Regression analysis for Pb and Ni in the top 5 cm of soil for every site throughout the entire basin.. ………………………………………………………………………139
D-4. Regression analysis for Pb and Ni in the top 5 cm of soil for sites located in cell 1…140
xii
Abstract of Thesis Presented to the Graduate Schoolof the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science
EVALUATION OF SELECTED HEAVY METAL CONCENTRATIONSIN SOILS OF AN URBAN STORMWATER RETENTION BASIN
By
Mark S. Lander
December 2003
Chairman: Mary E. CollinsMajor Department: Soil and Water Science
Treatment and disposal of urban stormwater runoff have become major concerns
when attempting to protect our surface and groundwater resources. Regulatory practices
of the past were developed as watershed management tools, placing minimal emphasis on
stormwater pollutant loads. Today, though, advanced studies in stormwater collection
have shifted focus from a water quantity control issue to that of water quality. Currently
the Florida Department of Environmental Protection, all five Water Management
Districts, and local governments are working together to develop safe stormwater
management regulations. With basin design being orchestrated for maximum water
quality treatment, the soil becomes an integral part of system construction. However, the
soils efficiency for pollutant removal from surface water may decrease overall soil
quality, in turn promoting an unsuitable environment within the basin for the existing
ecosystem. Degradation of soil quality through pollutant accumulation raises issues on
basin remediation and soils handling and disposal.
xiii
This study was done to evaluate the condition of soils inside a constructed
wetland detention basin at the Natural Area Teaching Laboratory (NATL) site in
Gainesville, Florida. Sampling was conducted inside the retention basin with the soils
being analyzed for field parameters and heavy metal contaminant concentrations.
Selected contaminant concentrations for Cd, Cr, Cu, Ni, Pb,and Zn were measured and
their distribution within soils of the wetland basin studied.
The results indicated that metal concentrations in the upper 10 cm of the
stormwater basin soil varied for Cd (0.0 mg/kg – 2.5 mg/kg), Cr (12.0 mg/kg – 262
mg/kg), Cu (3.0 mg/kg – 235 mg/kg), Ni (4.0 mg/kg – 31.5 mg/kg), Pb (0.5 mg/kg – 64.5
mg/kg), and Zn (6.5 mg/kg – 720 mg/kg). Several of these sites exceeded soil quality
reference guidelines used for contamination assessments. The majority of the
contamination lay adjacent to stormwater inlet pipes in the constructed wetland. The
proximity and extent of metal concentrations did not suggest their migration outside of
the constructed wetland.
1
INTRODUCTION
Urban Stormwater Runoff
Urban stormwater runoff has long been considered a major contributing factor of
non-point source pollution to both surface and groundwater resources. The loss of
permeable soil surfaces through urbanization can be expected as Florida’s population is
calculated to reach above 20,000,000 by the year 2020 (Florida Department of
Environmental Protection, 2001). As land becomes covered with impervious barriers
such as concrete and asphalt, infiltrative soil pathways become blocked, generating an
increase in stormwater runoff during rainfall events. Estimations made by the Florida
Department of Environmental Protection (FDEP), indicate that a 10% to 20% increase in
impervious surface area can double the amount of stormwater runoff generated during a
rainfall event (Livingston and McCarron, 1991). Stormwater runoff can reach as high as
55% of the total rainfall event if between 75% and 100% of land surfaces become
covered due to urbanization (Figure 1).
When exposed to impermeable surfaces, stormwater runoff collects materials
deposited between past rainfall events. Runoff from impermeable surfaces has been
shown to contain significant amounts of hazardous contaminants, such as heavy metals,
petroleum hydrocarbons, pesticides and many other types of organic chemicals (Cox et
al., 1998). Previous research has shown variability in contaminant concentrations at the
same site over time (Livingston and Cox, 1995). It is this unpredictability that makes
2
urban stormwater runoff an environmental threat. Without knowing the extent or even
the kinds of contaminants in urban stormwater runoff it is difficult to assess the
environmental implications that may be occurring. It is this same variability that makes
establishing proper regulatory guidelines for the management of urban stormwater so
important.
Figure 1. Increased stormwater runoff expectations due to the loss of permeable soilsurfaces (Diagram taken from The Florida Department of Environmental Regulationreference manual, Stormwater Management, A Guide for Floridians, Livingston &McCarron, 1991.)
Florida’s Stormwater Management Program
The current state infrastructure for urban stormwater management consists of a
multi-agency coalition between the Florida Department of Environmental Protection
(FDEP), Florida’s five regional Water Management Districts (WMDs), and local
governmental agencies (Figure 2). The FDEP serves as the umbrella agency for urban
stormwater regulation by implementing the state’s Non-Point Source Management
Program (NPSMP) (Cox et al., 1998). Regional regulation of the NPSMP has been
3
delegated to the WMD’s allowing for more flexibility to address centralized issues
through regional goals & policies. Local government has the responsibility for adopting
comprehensive land use plans in accordance with the state’s land planning agency, the
Florida Department of Community Affairs (DCA). By developing and implementing
stormwater master plans addressing current and future growth expectations local
governments have the ability to establish controls for monitoring the operation and
maintenance of stormwater collection systems. In addition to their regulatory capacities,
local governments have been given the authority to establish stormwater utilities fees
creating funding sources for local stormwater programs, thus making cities less
dependent upon state funding for program implementation.
Figure 2. Current agency infrastructure with respect to stormwater regulations.
The Florida Department of Environmental Protection(Non-Point Source Management Program)
Florida’s Five Regional Water Management Districts(Regional Goals Addressed Through Watershed
Management)
Local Governmental Agencies(Regulation Through Local Comprehensive Plans)
4
Stormwater Management Systems
With the regulatory controls in place, urban stormwater runoff is addressed under
the NPSMP by the use of stormwater management systems. Common types of these
include retention or detention type basins. These systems are designed to collect, hold
and treat stormwater before reaching its final destination, whether it is ground or surface
water recharge. Older stormwater basins were designed for water storage with little
attention being placed on treatment (Athayde et al., 1983). New basin construction and
some older retention basins are being redesigned using Best Management Practices
(BMPs) within the stormwater management system, such as grassed swales and
constructed wetlands to treat stormwater pollutants. Vegetation and soils in combination
with varied water retention periods may play a major role in cleansing pollutants from
stormwater entering these systems.
Deficiencies in Stormwater Regulation
Over the past 30 years the focus of stormwater management has shifted from a
water quantity based approach to that of overall water quality. Current regulations
address criteria that must be met for the storage capacity of stormwater basins and for
water quality in systems that discharge to surface waters. Pollutant toxicity build up in
stormwater basin soils is not addressed, unless the soils are being considered for land
application or landfill disposal. Even these concerns have led to only unofficial disposal
requirements.
It’s the soil’s ability to partition certain pollutants that make it both desirable and
hazardous to the ecosystem of the overall stormwater management basin. Without proper
controls, excessive pollutant loading of soils in stormwater basins may lead to elevated
5
levels of contamination, that under certain environmental conditions could become
available for exposure to humans, aquatic organisms and other various wildlife species.
Livingston and Cox (1995) studied sediment toxicity buildup in stormwater basins to
establish guidelines for sediment disposal. This study was expanded upon in 1998
looking at comparisons of pollutant buildup over time in basin sediments to the specific
land use category. The recommendations for remedial action as a measure of loading
time were difficult to assess due to sampling inconsistencies between locations. It was
determined that more data would be required before sediment disposal guidelines can be
established (Cox et al., 1998).
The argument opposing soil toxicity concerns is supported by the ideology of
presumptive operation and maintenance. That is, stormwater retention basins are
designed to collect and treat runoff before it is allowed to re-enter a clean water source.
With loading of stormwater basin soils by contaminants assumed, and as long as the
basin is being maintained and operating as originally permitted, the contamination
becomes a function of the permit (Still, 2000). A second reinforcing factor to this
argument is that, in general, stormwater basins are not created for, or intended to be part
of a human/wildlife exposure scenario. As the use of integrated wetlands in stormwater
treatment basins become more prevalent, however, this interaction becomes inevitable.
Research Site
The stormwater retention basin at the Natural Area Teaching Laboratory (NATL),
located on the campus of the University of Florida, is representative of how the second
assumption in regards to stormwater contaminant issues may be flawed. The basin,
which first was designed to collect and treat stormwater for disposal through slow soil
6
infiltration, initially had minimal emphasis on vegetative or ecological communities.
Through redesign, however, this basin has now become an integrated wetland, creating
an attractive environment for wildlife such as alligators, wading birds, and other avian
species (Figure 3).
In addition, the University of Florida has begun to use this facility as an
interactive research site. Previous literature suggests, that while constructed wetlands
have become effective BMPs for secondary wastewater treatment, their ability to treat
urban stormwater runoff has not been extensively studied (Carleton et al., 2000). This
site offers researchers the ability to assess basin performance and the effectiveness of
various wetland species and basin design with respect to stormwater treatment. By
making this site available for study and creating a desirable environmental habitat
through vegetative cover and water resources, exposures to possibly harmful levels of
toxic contaminants becomes an issue.
Figure 3. Photograph of the stormwater management system at the Natural AreaTeaching Lab, looking south.
7
Overall Research Objectives
There are currently no regulations requiring monitoring of stormwater retention
basin soils for contaminant build-up. A practical solution, may be to increase public
awareness on stormwater constituents, and their ability to accumulate in these basins. In
addition, the owners of these systems may not realize the potential exposure hazards that
exist. The objectives of this study were developed around the lack of regulatory
requirements for stormwater basin soils, and public awareness.
First, by evaluating soils throughout the basin for metal concentrations, organic
matter content, organic carbon content, pH, and particle size, issues concerning health
implications not currently considered in basin permitting considerations could be
addressed.
A second goal of this study was to generate background data on the stormwater
retention basin for the University of Florida to use with future studies at the research site.
These data could provide valuable information for evaluating wetland efficiency in
treating stormwater, as well as in providing insight to the current condition of the basin.
Soils play an integral role in determining how various land developments may
proceed. On some occasions short-term treatment capabilities of soils are considered for
permitting possibly overlooking long-term effects. Therefore, a third outcome of this
study is to increase awareness on soil contamination in stormwater management systems.
Understanding of such systems can lead to protective measures which can create a safe
working environment for all.
Throughout this document, a number of acronyms are used for various agencies
and technical documents. A table defining all acronyms used in this thesis can be found
in Appendix A.
8
LITERATURE REVIEW
Characteristics of Urban Stormwater Runoff
Improper management of stormwater runoff from urbanized areas can have a
downstream affect on both ground and surface water resources. Focus of stormwater
regulation in the past had been limited to issues of sediment control or flood relief.
Today this regulatory trend is shifting towards a water quality approach, recognizing the
many different pollutants carried within stormwater (Athayde et al., 1983).
A study released by the Nationwide Urban Runoff Program (NURP) in 1983,
detailed a variety of stormwater pollutants being identified in urban runoff. Two of the
primary contaminants detected were heavy metals and organic priority pollutants, such as
pesticides and volatile organics.
Results from the NURP study indicated that heavy metals were more frequently
detected in stormwater runoff than any other priority pollutant. While all of the 13 metals
on EPA’s priority pollutant list were detected in runoff analyzed for this study, copper,
lead and zinc had the highest detection percentage, found to be present in at least 91% of
the samples. In some instances concentrations were detected above freshwater acute
criteria and federal drinking water standards (Athayde et al. 1983).
Organic pollutants were not detected at the same frequencies as the metals.
Volatiles, pesticides, and phenols made up the majority of organic priority pollutants
detected. Detection values ranged from 22% of the samples to less than 10% for others.
9
A possible limiting factor for detection may have been that the monitoring scheme used
allotted only a limited number of priority pollutant samples taken (Athayde et al., 1983).
Further contaminants noted during the study were coliform bacteria, nutrients, oxygen
demanding substances, and total suspended solids (TSS). Additional studies have
indicated that copper, zinc, cadmium, lead, and possibly nickel, are major components of
pollution from urban stormwater runoff (Mikkelsen et al., 1997).
There is difficulty in predicting pollutant loads within urban stormwater runoff.
Variability of pollutant concentrations have been seen at a particular site from one storm
event to the next (Athayde et al., 1983). Another factor determining variability may be
seasonal influences. Higher concentrations of pesticides may be detected in stormwater
runoff during warmer months, when land application increases. In contrast, volatile
components may decrease during summer as the temperature controls volatility (Fischer
et al., 2003). With stormwater runoff, the goal is to direct flows from watershed areas to
a defined boundary for isolation and treatment. Retention basins may act as a pollutant
trap for various contaminants through soil adsorption and volatilization, other more
soluble contaminants may pass through these systems to groundwater (Mikkelsen et al.,
1997).
Methods of Stormwater Management Control
As our knowledge of identified pollutants carried within urban stormwater runoff
increases, and we determine the threats that they may pose to natural resources, questions
on how to control this problem must be addressed. The current response is to mix
methodologies of the past with the concept of best management practices (BMPs). In
10
some instances there may not be one solution to a stormwater runoff problem, but instead
a variety, or train of applications may exist within a single stormwater system.
Best Management Practices can be separated into two distinct categories; non-
structural, and structural. Non-structural BMPs rely heavily upon public education and
regulatory controls for effectiveness. Making consumers aware of potential impacts from
everyday household chemical usage, may lead to less overuse or abuse. Additionally,
regulatory constraints along with proper planning can control materials and in turn
develop acceptable guidelines for application (Lawrence et al., 1996).
Structural controls are methods used in stormwater systems to reduce the impacts
of erosion, flooding, and the magnitude of pollutant loading to waters. Methods of
structural controls are developed around the collection and containment of stormwater to
allow for settling and filtration, as well as chemical and biological treatment. The
particular methods used in structural controls should be designed around site specific
characteristics.
In Florida, particularly in the southern part, high wet season water tables create a
need to protect groundwater supplies from contamination by polluted stormwater runoff.
In these areas, the most common type of stormwater management systems are retention
or detention type basins (Rushton & Dye, 1993). Retention basins are designed to collect
and retain stormwater runoff on site. The processes of treatment are infiltration through
the soil and loss through evaporation. Detention basins are similar to retention, in the
aspect of stormwater collection, but in fact, their primary objective is to act as temporary
storage of stormwater before releasing it to a downstream water body. Extended
stormwater residence times between 24 and 48 have been shown to be effective in
11
allowing for sedimentation of suspended particles and microbiological treatment of
stormwater contaminants. Both retention and detention basins have been shown to
remove metals from stormwater with an efficiency between 60 and 80% (Lawrence et al.,
1996).
In some instances more than one BMP is used in a single stormwater treatment
system. Examples of other methods include percolation trenches, grassed swales,
pervious pavement, vegetative waterways, and street sweeping. Many of these methods
rely heavily upon either quick infiltration or vegetative species to reduce pollutant loads.
One emerging BMP in stormwater treatment is the usage of wetlands in combination with
retention or detention systems.
Studies have indicated the ability of wetlands to act as a filter or sink for
stormwater pollution either through sedimentation or soil adsorption, while providing
flood protection. The dominant process in pollutant removal from stormwater may be
sedimentation, however, indications are that vegetation and sediment/organic matter
relationships can be important in providing sites for metal precipitation (Walker and
Hurl, 2002). Goulet and Pick (2001), studied the effects of cattails on metal
concentrations and partitioning in surficial sediments of a wetland basin. Their study
indicated that the presence of cattails did not appear to have an affect on metal
concentration or partitioning of metals within the stormwater sediments. It did show that
areas where cattails were present tended to have higher organic content within the
sediments than zones where emergent vegetation did not exist.
Cheng et al. (2002) evaluated the metal uptake in the tropical-subtropical swamp
species C. alternifolius and V. exaltata. Contaminated stormwater passing through a
12
wetland planted with the species experienced heavy metal removal rates at approximately
100% from inflow effluent metal concentration to water exiting the system. A
comparison was made between metal accumulation in the soils and plants. C. alternifolius
proved to be an efficient vegetative species for removing heavy metals. In addition to its
ability to uptake pollutants, many plants store these contaminants in underground organs,
but C. alternifolius stores them in lateral roots forming just below the soil-water interface.
This makes it necessary to remove only a few cm of contaminated soil when attempting
site remediation (Cheng et al., 2002). Further studies using both floating and emergent
vegetation have shown similar results of heavy metal removal, reducing their
concentrations to an average of 85% (Kao et al., 2001). With removal of contaminants
being a primary focus on environmental protection, we might expect to see more systems
relying on vegetative wetlands as a BMP style.
Evolution of the Florida Urban Non-Point Source (NPS) Management Program
In Florida, increasing concerns of surface and ground water degradation through
contact with contaminated urban stormwater has led to changes in the methodology for
stormwater disposal. In the past, urban stormwater runoff was addressed as a water
quantity problem, controlled by collection and storage methods. However, by the mid-
1970s evidence was present indicating that over half the pollutant load entering Florida
waters came from non-point source runoff (Rushton et al., 1993). To combat the
concerns of pollutant loading to water resources from urban stormwater runoff, Florida
developed a comprehensive watershed management program involving federal, state,
regional, and local governments.
13
Regulation of urban stormwater runoff is vital in preserving Florida’s
environmental resources. Up until 1960, water quality effects from stormwater pollution
received little attention (Athayde et al., 1983). From 1960 until the early 1970s, studies
began to address pollutant identification in stormwater, but little significance was given
to developing specific discharge requirements. In 1972, the Federal Clean Water Act was
amended to prohibit the discharge of any pollutant to navigable waters unless authorized
by a National Pollutant Discharge Elimination System (NPDES) permit. Non-point
source pollution was now being recognized as a major contributing factor to water quality
problems. With the promulgation of EPA’s first stormwater regulations in 1973, urban
runoff was exempted unless coming from an industrial or commercial process containing
known contamination. In addition, regulation of the smaller urban stormwater discharges
was left up to state and local governments.
The lack of direction in stormwater management in the mid-1970s led to initiation
of the Nationwide Urban Runoff Program (NURP). The goals of the NURP were to
provide all levels of government with management options for handling polluted
stormwater discharges. It was these national investigations along with various Florida
studies, which laid the foundation for Florida’s Urban Stormwater NPS program.
In 1979, Florida’s first stormwater rule, Chapter 17-4.248, F.A.C., was
implemented by the Department of Environmental Regulation (DER). Under this
Chapter, the issuance of stormwater permits was dependent upon the “significance” of
discharge. Variability in the determination of “significant” by regulators made this an
impractical approach. The state’s Environmental Regulation Commission adopted a
revised stormwater rule, Chapter 17-25, F.A.C., in 1982. Past concerns of
14
inconsistencies in permitting were addressed by requirements for permits on all new
stormwater discharges and for modifications to existing discharges where pollutant loads
increased (Florida Department of Environmental Protection, 1993). With the adoption of
the revised chapter, Florida became the first state in the country to require the use of
BMPs as a practical method of stormwater treatment. In effect, performance based
standards established in Chapter 62-40, F.A.C., were set to control quantity and quality of
stormwater discharges, with emphasis placed on water quality exiting the system.
From 1984 to 1986 the focus of regulation shifted from state to regional. The
Southwest Florida Water Management District (SWFWMD), St. Johns River Water
Management District (SJRWMD), and Suwannee River Water Management District
(SRWMD) adopted regulations in line with DER stormwater rules, allowing DER to
delegate permitting authority to each WMD. Thus, stormwater rules were put in place to
address watershed management needs on a regional basis instead of the state as a whole.
Building upon the DER – WMD stormwater permitting relationship, the Florida
Legislation modified Chapters 373 and 403, F.S. The overall effect was the combining of
the WMDs Management and Storage of Surface Waters permit with the newly formed
Department of Environmental Protection’s (DEP) Wetland Dredge and Fill permit. The
combination of these two permits created what is now known as an Environmental
Resource Permit (ERP). ERPs allow either agency to evaluate both stormwater quantity
and quality impacts, depending upon the proposed development.
State and regional regulation are not the only controls when determining
stormwater project acceptability. The DCA is the agency responsible for the
implementation of the state’s growth management program. Several statutes establish
15
goals and directives for growth management throughout Florida. Specifically, Chapter
163, F.S., contains language including the Local Government Comprehensive Planning
Act and Land Development Act of 1985. Both address local government’s
responsibilities in land management, defining the requirements for the preparation of
local comprehensive plans and direction of land development. The direction of the local
government must be in conformance with the overall policies set forth by the state and
regional regulators (Florida Department of Environmental Protection, 2001).
Regulation of Stormwater in Alachua County
Local Governmental Regulations
Stormwater management systems in Alachua County are subject to review at the
local, regional, and state levels. The City of Gainesville and Alachua County each has its
own ordinance regulating stormwater management systems. City Ordinance, Chapter 27,
Article V, Section 27-238 (1998), established the formation of a water management
committee. The responsibility of the committee is to assess water quantity and quality
issues, and to assist in the development and implementation of sound water management
practices. Included issues are stormwater discharge and erosion and sediment controls in
stormwater management systems. Jurisdiction of the committee extends within the City
boundaries as well as adjacent lands, which may affect the City watershed areas. In
addition, Chapter 30, Section 30-270 (1992), addresses applicable standards for erosion
and sedimentation control, design, and maintenance of stormwater management systems.
However, the design phase defaults to existing state and WMD codes, with emphasis
based on storage capacity and discharge quality of stormwater.
16
Alachua County has taken a similar approach to addressing stormwater issues in
its unincorporated areas. Title 4, Chapter 44 (1996), established a stormwater
management utility (SMU) to oversee permitting outside all unincorporated boundaries.
The SMU, made up of the board of County Commissioners, is responsible for regulating
all stormwater discharges through a review of conceptual plans, proposed system usage,
required maintenance, and continued operation of stormwater management facilities. As
part of the Local Government Comprehensive Planning and Land Development
Regulation Act established under Chapter 163, F.S., Alachua County adopted Title 34,
Chapter 343 in 1992. Under 343, design, construction and operation components of
stormwater management systems are defined. As with the city ordinances, basic
regulation is adopted from state and WMD regulations. Emphasis on flood control and
storage capabilities, along with ground and surface water protection is in large the driving
force behind county regulations.
Additional local governmental regulations regarding stormwater discharges and
water quality have recently been implemented. The Alachua County Environmental
Protection Department (ACEPD) drafted a 2002 ordinance pertaining to water quality
standards and management practices for both the incorporated and unincorporated areas
of Alachua County. The ordinance, which became effective January 1, 2003, establishes
new standards defining allowable discharges to stormwater systems. Erosion and
sediment controls will be increased throughout the county, and powers of enforcement on
non-compliance or illicit activities will be given to the ACEPD.
Water Management Districts
Regional permitting for Alachua County is handled through delegation from the
FDEP to the WMDs. The majority of watershed issues in Alachua County are directed
17
either through the Suwannee River Water Management District (SRWMD) or the St.
John River Water Management District (SJRWMD). The stormwater basin for this
research is located near the center of Alachua County in the northwestern portion of the
SJRWMD (Figure 4).
Figure 4. The location of the Stormwater Ecological Enhancement Project (SEEP) at theNatural Area Teaching Lab (NATL) in Alachua County.
Permitting requirements for stormwater runoff in the SJRWMD are established in
several regional codes, using ERPs as the mechanisms for regulation. Chapter 40C-4,
18
Surface Water Management Systems, establishes guidelines for the management and
storage of surface waters located within the District. The structure of these guidelines is
in accordance with FDEP standards set forth in Chapter 62-40, F.A.C., and Chapter 373,
F.S. Under Chapter 40C-4, the SJRWMD has established conditions for stormwater
permitting in addition to defining a management structure for regulatory purposes.
Taking stormwater management a step further, in Chapter 40C-42, Regulation of
Stormwater Management Systems, the District established standards to control discharges
initiated from stormwater runoff. Included within the chapter are requirements for
system design and construction, performance criteria, special exemptions, operation,
monitoring, and maintenance.
As with the local ordinances established for stormwater runoff, WMD and FDEP
regulations address mainly water storage and quality of discharge issues. Requirements
for monitoring pollutant build-up in stormwater sediments are not addressed to any
extent. To better understand the regulatory absence on soil contaminant build-up, phone
interviews were conducted with both SJRWMD & SWRMD staff. Information from the
interviews indicated that permitted stormwater management systems are inspected on a
routine basis. The emphasis of the inspections is on sediment and debris accumulations,
and structural integrity of the basin. Soil contaminant concentrations are not evaluated
unless the permitting agency has reason to suspect the basin is not functioning as it was
originally permitted. The neglect of contaminant evaluation requirements is justified by
the term “presumptive operation and maintenance.” In simple terms, stormwater
retention basins are designed and constructed to collect and treat runoff for pollutant
removal before allowing infiltration to ground and surface water resources. A major
19
component of the treatment process is the soil’s ability to filter out contaminants at its
infiltrative surface. If a stormwater system is functioning properly, then the removal of
pollutants from the water column and subsequent build-up of contaminants in the soil is
merely a function of the system. A second part of the equation of pollutant soil build-up
in stormwater management systems is the fact that these basins are not designed with the
intent of frequent human and wildlife interactions. The intent of stormwater management
is to localize contaminants by directing stormwater to a centralized location. Access to
these areas is then commonly limited or discouraged through the use of fencing or other
restrictive measures.
This last thought process is not the case with the NATL stormwater retention
system. There are no restricted barriers to limit public access, such as chain link or
stockade fences. The only defining border around the basin is a 4-board fence to the east
and north with several access points (Figure 5). In addition to not limiting access, a
boardwalk has been installed inside the stormwater basin, which allows entry to almost
the entire area (Figure 6). Additionally, basin landscaping has created an environment
that attracts and sustains a variety of wildlife. The research opportunities created by the
stormwater basin make this area a valuable site for the University. A lack of current
stormwater soils data at this location creates a great opportunity of study. It is should be
recognized though, that the absence of requirements for contaminant regulation in
stormwater basins may create a potentially hazardous working environment.
20
Figure 5. Photograph of four-board fence bordering the eastern and northern region ofthe stormwater retention basin at the Natural Area Teaching Lab.
Pre-Stormwater Retention Basin Soil Quality
Lacking actual laboratory data on the soils in the vicinity of the stormwater
retention basin, soil quality before the construction of the retention basin could only be
estimated. The control samples located outside the retention basin gave insight to surface
horizon conditions. Additionally, logs of soil borings completed during the initial
construction phase on the stormwater basin were located and compared to existing soil
maps of the area, giving a broader view of the subsurface horizons that existed pre-basin
construction (Beville, 1988).
Figure 6. Diagram of stormwater retention basin. A) Boardwalk location in the retention basin as noted by red line. B) Photographof students using the boardwalk to enter the retention basin.
A)
Boardwalk
B)
21
22
Soil maps in the Soil Survey of Alachua County Florida (Thomas et al., 1985),
indicate that before this area was dedicated entirely to stormwater management the
dominant soil series in the area were Arredondo, and Kendrick. The classifications of
these soils are similar as are their parent materials. Both series are in the Ultisol order,
but the Kendrick series is classified as a loamy, siliceous, semiactive, hyperthermic,
Arenic Paleudult, indicating a shallower argillic horizon present than in the Arredondo,
which is classified as a loamy, siliceous, semiactive, hyperthermic, Grossarenic
Paleudult.
Soil borings, conducted by Dr. Bishop Beville in 1988, indicated the major soil
materials to be fine sands overlying fine sandy loam and sandy clay loam horizons.
These borings were taken at selected areas within the then proposed retention basin being
constructed around an existing natural depression. Additionally, it was noted in several
areas that the “clayey materials” were close to the surface, indicating possible removal of
the topsoil. The sandier soils were determined to be located in the northern end of the
site, in what is now the forebay. Fine-sand textured soil material was measured to depths
of between 76.2cm to as deep as 167.6cm, with the exception of one site at the
northernmost point of the basin (Beville, 1988). The remaining fine sand horizons
became thinner as the existing pond was encroached upon. The presence of water tables
at several borings was probably due to the perching ability of the clay in the subsurface
horizons and the fact that this area, the existing pond, was the natural watershed for the
surrounding lands. These documented water tables are not typically observed in the
Kendrick or Arredondo soils. However, water tables can be present in the Millhopper
soils, which is geographically associated and classified the same as Arredondo. Another
23
indicator hinting to the clays ability to hold or retain water, was the identification of
redoximorphic features within and above the argillic horizons. Data from the soil boring
logs, matrix color or indicated “mottles, suggested the presence of either a current or wet
season water table within 2 m at every location (Beville, 1988). A complete list of the
soil borings and a map detailing their locations within the proposed basin are in Appendix
B, Figures B-1 through B-5.
Working on the assumption that the soil series at the location of the stormwater
basin were either Kendrick, Arredondo, or Millhopper, estimates on soil quality
parameters can be obtained from Tables 15 and 18 in the Soil Survey of Alachua County,
Florida (Thomas et al.., 1985).
The soil survey gives estimates in the ranges in organic matter content for the
surface horizons of the three soil series in question. Both the Kendrick and Arredondo
soils have an estimated organic matter content of less than 2% in their surface horizons.
The Millhopper soil has a range of 0.5-2% organic matter content in its surface horizon.
The soil survey additionally lists laboratory data from the Environmental
Pedology Lab in the Soil & Water Science Department at the University of Florida. pH
and organic carbon content are shown for different soil series. The pH for surface
horizons in these three soil series ranges from 5.6 in the Kendrick series to 6.0 in the
Arredondo soil. The Millhopper soil has a pH in the surface horizon listed at 5.9. The
subsurface argillic horizons, which are now exposed due to the creation of the stormwater
basin, would have a pH range of 5.2–6.0 in their original pedogenic stages. Organic
carbon content in the surface horizons of these soils ranges from 0.15% in the Arredondo
soil to 0.57% in both the Kendrick and Millhopper soils. With increasing soil depth,
24
organic carbon content decreases. In the Millhopper soil, the organic carbon content
decreases to approximately 0.03% in the Btg horizon, while the organic matter content of
the Bt horizon in the Kendrick soil is between 0.13–0.15%. The Arredondo soil shows a
range of 0.06–0.09% organic carbon content in the Bt horizons.
It should be noted that these numbers are not absolute for the soils that were
present in the area of the stormwater basin before its construction. However, by using
these as a reference point and comparing them to current conditions, insight on
anthropogenic influence from urbanization can be observed.
Permitting of the Retention Basin at the NATL
The retention basin serving the NATL was first permitted by the SJRWMD in
1988 under the University of Florida Master Drainage Plan as Basin #8. The original
design criterion was based on stormwater collection from a 14.45 ha watershed.
Stormwater runoff from a 100-year storm event based on a 24-hour period was calculated
to be 18,855 m3 for this watershed. Additional runoff from the Entomology/Nematology
Building and from the Florida Department of Transportation (FDOT) Park ‘N’ Ride lot,
serving the University of Florida, was directed to the basin in 1990, bringing the entire
watershed area to approximately 16.19 ha, increasing the total runoff flows to31,075 m3.
A note to the master plan indicated the proposed maintenance of the system to include
monthly inspections, and inspections after each major storm event for debris and erosion.
Additionally, silt removal from the basin bottom in the areas of the outfall locations was
to be completed twice a year. There was, however, no reference to the evaluation of soil
sediments for contaminant build-up. In 1996, SJRWMD permit #40-001-0029AG, was
issued for the re-contouring of the SEEP due to the system being redesigned with the
25
constructed wetland. Under this permit, conditions of the original application were
maintained with no requirements for sediment analysis. Basin function evaluation on
storage capabilities and structure continued to drive the permitting side of UF Basin #8.
Review of Past Stormwater Management Studies In Florida
Over the past 10 years there have been a number of stormwater studies in Florida
that have led to either direct or indirect regulations being applied to permitting practices.
These studies have included evaluations on BMP styles, treatment capabilities of
differing basin classifications, and land use impacts on stormwater quality. With
emphasis in these studies being placed on water quantity and quality, soil evaluation for
contaminants many times is looked at as a side note. In 1995, however, DEP completed
an intensive literature review and monitoring project of stormwater systems across
Florida. When DEP completed its literature review, it was noted that existing data on
stormwater sediment characterization was sparse and not easily correlated due to
variation in sampling methodologies (Livingston et al., 1995). From the data obtained in
previous studies, and those collected during the course of the 1995 investigation, DEP
evaluated stormwater sediments from over 87 sites, from differing land use
classifications, within Florida. Sediment screening took place for a total of 168 different
pollutants, including pesticides, organic contaminants and trace metals (Cox and
Livingston., 1995).
Metals in the DEP study were evaluated for their concentrations and ability to
leach from soil to solution. Pollutant comparisons were made to several different state
regulations regarding soil contamination and cleanup. The six most common metals
found during this study were chromium (Cr), lead (Pb), zinc (Zn), copper (Cu), cadmium
26
(Cd), and nickel (Ni). Concentrations of Cr, Pb, and Zn were detected at 100% of the
sites. Cu was next with a 94% detection level, then Cd, followed by Ni, with 72% and
67% concentrations, respectively. It was noted that as a group metals were the most
frequently detected runoff related pollutant identified during this study (Cox et al..,
1998). When compared to Soil Cleanup Target Levels (SCTLs), of the six most
commonly identified metals, only Pb exceeded these parameters at a frequency of 3.5%.
For leachability, Pb exceeded criteria at 80% of the sites, followed by Cr in 9%, and Cd
in 6% of the samples. In terms of the Sediment Quality Assessment Guidelines
(SQAGs), Pb was the most problematic metal, exceeding standards at 39% of the sites.
Pb, Cu, Zn, and Cd were also identified in 22% to 11% of all samples screened. The
majority of contaminants detected above cleanup criteria during this study were
distributed within the first 2.54 cm of soil, except for Pb, which was identified exceeding
cleanup criteria at a depth of 20.32 cm.
Information obtained from the 1995 study and 1998 final report indicated the need
for future studies in soil contamination to develop adequate disposal guidelines.
Environmental protection values, such as those established in the SCTLs, and the
SQAGs, are currently applied indirectly when considering stormwater soil disposal. It
was also noted that past recommendations for soil removal based on accumulation rates
did not address variable loading rates due to land use category. It suggested more data be
accumulated to develop guidelines for proper soil removal periods. While the main intent
of this past research was to evaluate soil contamination for disposal purposes, the
concentrations and frequencies of several contaminants warrant further investigation into
the potential of acute and chronic effects on organisms from stormwater soils.
27
Criteria Used in Metal Contamination Analysis
Due to the absence of direct regulatory requirements for metal concentration
build-up in stormwater basin soils, evaluation of contaminant levels was accomplished
through applying several state regulations and guidelines that indirectly impact
stormwater maintenance facilities. To evaluate sediment contamination in relation to
human and wildlife concerns, SCTLs referenced in Chapter 62-777, F.A.C. were
observed. In addition, SQAGs developed for Florida’s coastal waters were used to
evaluate metal concentrations in relation to the aquatic environment. Both sets of these
comparative values have been used in other studies similar in nature to the NATL
stormwater basin evaluation. In addition to regulatory standards, baseline concentrations
for trace elements in Florida surface soils established by Chen et al..(1999) were
reviewed.
Chapter 62.777 F.A.C. – Contaminant Cleanup Target Levels
Values obtained in this chapter apply directly to sites governed by the terms of a
brownfield site rehabilitation agreement, pursuant to Chapter 62-785, F.A.C., and to
contaminants of concern defined under Chapter 62-770, F.A.C., Petroleum
Contamination Site Cleanup Criteria, Chapter 62-782, F.A.C., Dry-cleaning Solvent
Cleanup Criteria, in addition to the treatment of soils permitted under Chapter 62-713,
F.A.C., Soil Treatment Facilities (Florida Department of Environmental Protection,
1999). It should be noted that these values are intended for application only to sites
governed under the above referenced chapters. While they do not reference stormwater
soils, they are sometimes applied, however, when stormwater basin soil disposal options
are being considered (Livingston and Cox, 1995).
28
SCTLs for metals established in Chapter 62.777, F.A.C., have been separated into
two categories (Table 1). Each category defines differing levels of health protection
based on exposure criteria, such as dermal contact, ingestion, and inhalation. In addition,
variables such as body weight, exposure frequency, and exposure duration were all used
when developing the model for acceptable risk-based concentrations of contaminants in
soils.
The first, and more stringent of the two categories are the residential-based
exposure values. The greater level of protection for these comes from their availability of
access to the general public, such as children. The increased protection factor is based on
the fact that these sites are open to the public, and can be frequented by individuals with
no limited access. For this study, these values were applied when considering exposure
of contaminants to both human and wildlife communities in the area.
The second category, defined as commercial/industrial-based exposure values,
offers a lesser degree of protection. However, this is based on the assumption that access
to commercial sites is limited to the public, and exposure times could be regulated for
individuals working in these areas.
Table 1. Soil clean-up target levels (SCTLs) for contaminated soils
ContaminantCadmium 75 1300Chromium 210 420Copper 110 76,000Lead 400 920Nickel 110 28,000Zinc 23,000 560,000
Residential Exposure (mg/kg) Commercial Exposure (mg/kg)
29
Soil Quality Assessment Guidelines (SQAGs)
SQAGs are biological-effects based guidelines developed for FDEP to be used as
a tool when studying soil–associated contaminants in coastal environments. Data have
been collected by FDEP for over a decade and analyzed to establish these guidelines,
which identify ranges in concentrations of contaminants that have low to high
probabilities of causing adverse biological effects to aquatic organisms (Florida
Department of Environmental Protection, 2000).
An absolute determination of detrimental biological effects cannot be based solely
on the evaluation of SQAGs. These guidelines should be used in conjunction with other
available data, due to several limitations. Specifically, these guidelines represent
pollution potential only. Cause and effect relationships are not inferred when comparing
these guidelines to other chemical data. Another limitation is the issue of bioavailability.
Factors that can control metal sorption such as total organic carbon (TOC) are not
equated when deriving SQAG ranges. A third limitation is that the data used to develop
the guidelines were collected from across the country. How well these guidelines
represent all Florida soils is uncertain. In addition, these values were derived for coastal
water soils, not freshwater. However, with guidelines for freshwater systems currently
under development, the SQAGs for coastal environments have been indirectly applied in
past studies. While the use of SQAGs in contamination studies may have limitations,
their value as contaminant indicators is the first step in determining possible areas of
concern relating to soil quality.
To determine pollution potential from the SQAGs, ranges have been established
which divide each contaminant of interest in to three different categories (Table 2). The
first, and lowest pollution potential range is considered the no effects level. At these
30
concentrations the contaminants rarely or never are associated with adverse biological
effects to aquatic organisms. The second range is classified as the threshold effects level
(TEL). It is at this minimal concentration that contaminants frequently cause adverse
biological effects. Last of all, we have the range of highest pollution potential, classified
as the probable effects level (PEL). When concentrations of pollutants exceed the
minimum value of this range there are usually or always adverse biological effects on the
aquatic community exposed.
Table 2 Soil quality assessment guidelines for heavy metals in study. Values establishedin the Florida Department of Environmental Protection Soil Quality AssessmentGuidelines for Coastal Sediments
Contaminant No Effects Level Threshole Effect Level Probable Effect Level(mg/kg) (mg/kg) (mg/kg)
Cadmium 0 - 0.675 0.676 - 4.20 > 4.20Chromium 0 - 52.2 52.3 - 159.9 > 159.9Copper 0 - 18.6 18.7 - 107.9 > 107.9Lead 0 - 30.1 30.2 - 111.9 > 111.9Nickel 0 - 15.8 15.9 - 42.7 > 42.7Zinc 0 - 123.9 124 - 270.9 > 270.9
Baseline Concentrations for Trace Metals in Florida Soils
When comparing contaminant levels of trace metals to actual field values, it is
important to distinguish between natural-occurring metal concentrations and those that
may be attributed to anthropogenic sources. Years of contaminant inputs to soil makes
establishing true background concentrations difficult (Chen et al., 1999). Work
conducted by Chen et al. (1999) evaluated the use of baseline concentrations to estimate
natural levels of trace metals in Florida surface soils.
31
It was determined that the use of baseline concentrations better represented the
variation in trace metal concentrations, than did using the observed ranges. Log
transformations of the values minimized the few high concentrations, which could distort
the overall range (Chen et al., 1999). These baseline concentrations were used for
comparison in this study (Table 3).
Table 3. Baseline concentration for Florida Surface Soils (Chen et al., 1999)Metal Calculated Baseline Concentration (mg/kg)Cd 0 - 0.33 Cr 0.89 - 80.7Cu 0.22 21.0Ni 1.70 - 48.5Pb 0.69 - 42.0Zn 0.89 - 29.6
Metals
Stormwater has been shown to contain a number of different contaminants,
dependent upon the watershed collection area, that may pose health and environmental
threats to exposed communities. Metal concentrations in stormwater have been identified
through studies to be the most commonly detected contaminants at many locations.
Metal concentrations at sites may be a mix of natural occurrence and anthropogenic
inputs. The process of mass loading metals on soils already containing natural trace
metal concentrations could lead to the accumulation of potentially toxic levels of
contamination. In addition, the potential for human, animal, and aquatic organism uptake
and storage of metals internally could create long-term health concerns. To assess
concerns relating to heavy metal exposure, each contaminant should be evaluated on its
potential to affect human and environmental health. The following information on metal
32
toxicity was obtained through the Agency for Toxic Substances and Disease Registry
(ATSDR) website, located at www.atsdr.cdc.gov (ATSDR, 2001).
Cadmium (Cd)
Cd is an element that can be found naturally in the earth’s crust or used in a
variety of applications, including manufacturing of batteries, paint pigments, metal
coatings, and plastics. Additionally, the burning of fossil fuels can contribute to the
presence of Cd in the environment.
Cd can enter natural systems through deposition from air emissions, as well as
through leaching or washing of contaminated sites. Sediment contamination from Cd
occurs through sorption to organic matter, and through co-precipitation with iron, Al, and
Mn-oxides. It binds strongly to soil particles, not breaking down in the environment, but
rather changing forms.
Exposure to Cd occurs mainly through inhalation of contaminated air, ingestion of
contaminated food sources or through contaminated water supplies. The bio-availability
of Cd in sediments is dependent upon pH, redox potential, water hardness, and the
presence of other complexing agents. Studies have shown that animals exposed to high
doses of Cd experienced lung disease and stomach disorders. Cd ability to remain in the
body for a very long time allows for levels to build up, even if exposure concentrations
are low. Aquatic organisms exposed to Cd have shown various effects, including acute
mortality, reduced growth, and inhibited reproduction. It is unclear whether human
exposure to Cd will result in similar diseases when exposed to equal levels as in animal
studies. Exposure to Cd through dermal contact has no known effect in either humans or
animals.
33
Recommendations to protect public health have been made by several
governmental agencies. The United States Environmental Protection Agency (USEPA)
has established limits for Cd in drinking water set at 0.005 parts per million (mg/L). The
United States Food and Drug Administration (USFDA) allows up to 15 parts per million
(ppm) in food colorings, while the Occupational Safety and Health Administration limits
workplace air to 100 ug/m3 as Cd fumes, and 200 ug/L as dust particulate (ATSDR,
2001). Additional guidance concentrations have been derived for use with the SQAGs,
and SCTLs. SQAGs have established a TEL of 0.68 mg/kg, and a PEL of 4.2 mg/kg.
The SCTLs for exposure limits are set at 75 mg/kg for residential exposures, and 1300
mg/kg for commercial exposures.
Chromium (Cr)
Similar to Cd, Cr is an element that can be found occurring naturally in the
environment, as Cr(III), or as a byproduct from various industrial processes as Cr(0), or
Cr(VI). Processes involving the use of Cr include steel production, paint and dye
production, leather tanning and wood preservation.
Cr enters the environment through deposition from air emissions and leaching at
contaminated sites, mainly in the Cr(III) and Cr(VI) forms. Once introduced to a natural
system its fate depends upon the form at which it enters. In aquatic systems Cr(VI) tends
to be very soluble, not readily sorbed to particulate matter. However, as anaerobic
conditions prevail, Cr(VI) reduces to Cr(III), a state which can strongly sorb onto organic
particulates.
Exposure to Cr contamination occurs through inhalation, ingestion, or dermal
contact. Inhalation of high levels of Cr(VI) has been shown to cause nasal irritations
such as nosebleeds or ulcers. Ingestion of similar levels can cause stomach, liver or
34
kidney damage, which may result in death. Unlike Cd, dermal exposure to high levels of
Cr(VI) may result into skin ulcers. Individuals with severe allergies may experience
swelling and redness to exposed areas. Studies have shown Cr(VI) compounds can
increase the risk of lung cancer, and the several health organizations have labeled Cr(VI)
in various forms as a human carcinogen. Additional adverse effects to biological
communities include death and decreased growth, particular by vegetative species. Fish
do not tend to be as sensitive as humans to Cr contamination (ATSDR, 2001),
Federal regulations have been established by the EPA and OSHA to protect public
health from exposure to high levels of Cr. EPA recommends Cr concentrations in water
not to exceed 0.1 mg/L. In addition to drinking water standards, SQAGs and SCTLs
have been derived for contamination and remediation assessments. Under the SQAGs, a
TEL of 52.3 mg/kg and a PEL of 160 mg/kg have been established for aquatic biota
protection. The SCTLs for residential and commercial exposures are 210 mg/kg, and 420
mg/kg, respectively.
Copper (Cu)
Cu is a natural occurring metallic element in crustal rocks and minerals, released
during weathering processes. Anthropogenic sources of Cu include agricultural
fungicides, pesticides, sewage treatment effluent, wood preserving, and fallout from
industrial sources and coal burning.
Cu can enter natural systems through weathering of minerals, release in air
emissions, and through direct exposure as in soil or water treatment devices. Inhalation,
ingestion and dermal contact are the main pathways for Cu exposures to many organisms.
While Cu is considered an essential micronutrient, exposure to elevated levels in the air
can cause irritations to the nose and mouth. Ingestion of high levels of Cu can lead to
35
kidney and liver damage as well as stomach disorders. Dermal exposure to elevated Cu
levels can result in an allergic reaction or rash in sensitive individuals. There is no
indication that Cu exposures can lead to cancer in either humans or animals. However,
Cu contamination of aquatic systems may be associated with acute and chronic toxicity in
biotic organisms (ASTDR, 2001).
Human health concerns from Cu contamination have led to the establishment of
federal guidelines regulating consumption and workplace exposures. Drinking water
standards have been set at 1.3 mg/L. In addition to EPA and OSHA regulations,
protective levels have been derived under the SQAGs and the SCTLs. The SQAGs have
established a TEL of 18.7 mg/kg, and a PEL of 108 mg/kg. Residential exposure
guidelines established for SCTLs has been set at 110 mg/kg, while commercial exposure
limits are 76,000 mg/kg.
Lead (Pb)
Pb is a metallic element that is found in virtually all parts of our environment.
While it can be naturally occurring, anthropogenic sources contribute heavily to its
presence. These sources include the burning of fossil fuels, mining, and the
manufacturing of batteries, metal products, and ammunition. The use of Pb in many
items such as paints and gasoline has been greatly reduced due to health concerns.
Pb can enter natural systems through deposition with air particulates or by
leaching or washing of contaminated surfaces. Once Pb comes into contact with
sediments, its movement is dependent upon the type of Pb compound and soil
characteristics. Pb(II) tends to be the most stable ionic species, and can be found bound to
Fe and Mn-hydroxides in addition to clay and organic matter. Oxidized sediments tend
36
to bind closely with Pb, with its release and mobility increasing under reducing
conditions. The majority of exposures to Pb occur through ingestion or inhalation.
In humans, Pb exposures to high levels have been shown to affect the organs of
the body and the central nervous system. Blood disorders and male reproductive
problems may also occur. Aquatic organisms also exhibit toxic affects from Pb. Plants
tend to be less sensitive to exposures than fish or invertebrates. While studies involving
animals indicate the possibility of Pb to be a carcinogen, there is no evidence to suggest
carcinogenic effects in humans.
Federal agencies have set regulations to control Pb exposures through ingestion
and workplace incidences. Drinking water standards for Pb are set at 0.015 mg/L.
Additional recommendations have been made regarding Pb screening programs for
children who live in areas determined to be high risk zones (ATSDR, 2001). The SQAGs
have derived a TEL of 30.2 mg/kg, and a PEL of 112 mg/kg. SCTLs set exposure limits
at 400 mg/kg for residential classifications, and 920 mg/kg for commercial sites.
Nickel (Ni)
Ni is an element found abundantly in the earth’s crust, primarily combined with
oxygen and sulfur. Ore deposits often contain Ni with Fe or Cu. While Ni is used in a
variety of manufacturing and industrial industries, the major anthropogenic sources
include, fossil fuel combustion, batteries, Ni ore mining, smelting and refining activities,
and electroplating (FDEP, 2000).
Anthropogenic sources of Ni may enter environmental systems as small deposits
in air particles, or through the washing and leaching of surfaces containing Ni. As
anthropogenic sources are introduced to sediments they become bound as Fe or Mn-
oxides or they sorb with organic matter. Release of Ni from sediments may decrease
37
under anaerobic conditions as they form insoluble complexes with sulfides. Human and
animal exposures to Ni can be through inhalation, ingestion or dermal contact.
Ni is considered a required element for maintaining good health, but, exposures to
high levels can cause adverse health effects. The most severe exposures for humans and
animals in terms of health related concerns appear to be through dermal contact and
inhalation. Allergic reactions from contact with Ni, in the form of skin rashes, are the
most common types of health effect seen. Workplace exposure to air particles containing
Ni compounds have been linked to lung as nasal cancers. In terms of adverse effects on
aquatic organisms, increased mortality rates, decreased growth and avoidance reactions
have been observed.
With certain Ni compounds determined to be carcinogenic, federal agencies have
established recommendations regarding ingestion on water containing these compounds
(ATSDR, 2001). In addition to drinking water standards of 0.04 mg/L, occupational
exposure levels have also been established to reduce concerns from inhalation. For the
protection of aquatic organisms the SQAGs have derived a TEL of 15.9 g/L, and a PEL
of 42.8 g/L. SCTLs have been determined to be 110 ug/L for residential considerations,
and 28,000 ug/L at commercial sites.
Zinc (Zn)
Zn is an abundant element, found in air, soil, and water. As a crustal element it is
present commonly as a sulfide, carbonate, or silicate ore. Zn has a number of different
production uses, including dry cell batteries, rust preventatives, and as a mixture with
other metals to form alloys.
Release of Zn into the environment can occur through natural processes.
Anthropogenic inputs from air deposition and leaching also contribute to its presence.
38
Much of the Zn entering the environment stays bound to soil with Fe and Mn-oxides, clay
minerals and organic matter. Adsorption rates of Zn have been determined to be pH
dependent, showing a decrease in aquatic systems with pHs below 6. Sorption to organic
matter in fine grained sediments is controlled by reducing conditions, which form
insoluble sulfides (FDEP, 2000).
Health concerns over exposure to Zn arise from ingesting contaminated food or
water supplies, or from breathing aerosolized Zn particles near manufacturing plants. Zn
is an essential element to the diet of humans, requiring an appropriate balance to be
effective. Since our bodies require Zn, low inputs to our systems can be just as harmful
as exposures to high levels. Ingestion of high levels of Zn may lead to short-term
stomach and blood disorders and possibly pancreas damage. Inhalation of Zn at high
concentrations may cause lung irritations and body temperature fluctuations on a short-
term basis. Long-term effects for Zn inhalation have not been determined. Affects on
aquatic organisms appear to be minor as they can experience a wide range of sensitivity
to Zn exposure. Zn is currently not listed as a possible carcinogen (ATSDR, 2001).
Federal agencies have established recommendations for human exposures to Zn
contamination through drinking water of 0.005 mg/L, and workplace exposure
guidelines. To protect aquatic organisms, the SQAGs have recommended a TEL of 124
mg/kg, and a PEL of 271 mg/kg. SCTLs have been established at 23,000 mg/kg for
residential sites, and at 560,000mg/kg for commercial cleanup designations.
Metal Attenuation in Stormwater retention Basin Sediments
Stormwater runoff has been shown to contain various contaminants dependent
upon the input source. Metals, being one variety of stormwater contaminant, can
39
accumulate in stormwater soils depending upon soils characteristics, such as pH,
percentage of organic carbon, percentage of Fe and Mn oxides and existing metal
concentrations. As vegetation within stormwater systems decays, organic matter can
accumulate. Igloria, et al.. (1997), studied the effects of natural organic matter (NOM) as
a source for attenuation of metals in stormwater, and as a facilitator of metal transport
within stormwater basins. Their conclusions were that the addition of NOM did not
enhance metals transport, but in fact, the high affinity of the NOM to the soil in
combination with the metals attraction to the NOM decreased the metals mobility
(Igloria, et al., 1997). Another study evaluated Cu and Cd distribution in forested soils
and determined that organic matter or Fe and Mn-oxides were responsible for
immobilizing Cu, and that Cd attenuation was also dependent upon metal-oxide
relationships (Keller and Vedy, 1994).
Similar results for metal deposition in relation to organic matter were reported by
Walker and Hurl (2002), and Goulet and Pick (2001). Metal distribution has been shown
dependent upon not only its association with organic matter, but with stormwater basin
design, such as depth and planted vegetation. Stormwater basins with shallow water
column depths may allow for a larger distribution pattern due to water turbulence stirring
and moving sediments (Goulet and Pick, 2001). In addition, vegetation can act as a plug,
slowing the velocity of stormwater inflow and reducing the effects from wind on shallow
surfaces in retention basins.
Metal uptake within stormwater retention basin soils may play a large part in the
spatial distribution at which contamination is detected. In vegetative wetlands, Cd, Cu,
and Zn concentrations have been measured the highest in 0 – 5 cm samples, while Pb
40
concentration was shown to increase to a depth of 55 cm (Cheng et al., 2002). A study
conducted by Kao et al., (2001) compared contaminant removal rates from influent for
both vegetative and unplanted soils surfaces. In a wetland setting both Pb and Zn
concentrations decreased by 95% and 92% respectively, from stormwater inflow to water
quality exiting the system. Although lower, the unplanted treatment basin showed an
effluent contaminant removal rate of 32% for Pb, and 40% for Zn (Kao et al., 2001).
Typically redox potential may play a part in the partitioning of metals with
stormwater basin soils. In soils where the redox potential is greater than 100 mV, most
metals present within pore water will either precipitate as metal-oxides or adsorp to
organic matter. As redox potential decreases to between 100 mV and –100 mV,
reduction of metal-oxide can result in the release of dissolved metal back to solution. If
enough organic matter is present the metals may still adsorb, otherwise they may be
transported with the water column through sedimentation. Below –100 mV, metal-soil
relationships are developed strictly through reactions with monosulfides and organic
matter adsorption (Goulet and Pick, 2001).
Clearly studies have been completed which indicate relationships between soil
characteristics and their roles in metal attenuation. Sediments within the stormwater
retention basin at the NATL are no different that many of these study sites in terms of
organic content, contaminant input sources and other variables. Ignoring the possibility
of metal accumulation to potentially hazardous levels within sediments in the SEEP or
any other stormwater retention basin could be a dangerous oversight.
41
OBJECTIVES
In the past, urban stormwater retention basins served the purpose of collecting and
treating stormwater runoff before it infiltrated or discharged into a water resource.
Basins were not created nor intended to be used for recreational purposes or to be
considered quality habitats for wildlife or aquatic organisms. Access to these areas may
have been limited through locked gates or minimized by undesirable site conditions, such
as dry retention ponds. The situation is changing with the integration of wetlands into
stormwater basins emerging as a method of enhancing treatment to improve the quality of
discharge.
With the development of the stormwater basin at the NATL focused on increased
opportunities of study for students and faculty at UF, in addition to creating a diverse
habitat for wildlife, exposure to contaminants commonly found in urban stormwater
water runoff could occur through ingestion, inhalation, or dermal contact. Regulatory
considerations focus mainly on environmental protection through water quality
improvement, with little emphasis on soil quality.
The lack of regulatory guidance for stormwater soil contamination played an
important role in the development of the objectives for this study. Both the ability to
provide information that could be used in determining the direction of future stormwater
studies at the basin, and to specifically address contamination concerns related to the
usage of the basin as a research site and as a wildlife habitat, were desired outcomes.
42
Objective 1 – Evaluation of Current Soil Conditions for Future Studies
One anticipated study for the stormwater basin is to determine the efficiency and
effectiveness of the wetland design in pollutant removal from stormwater. Soils will play
an integral part in this process. No background levels of contamination or other soil
quality parameters exist for soils within the retention basin. By establishing these levels,
future studies can compare parameters similar to those that have been documented
through this research.
Objective 2 – Comparison of Current Metal Concentrations in Basin Soils to Soil TargetCleanup Levels
The University of Florida will continue to use the basin as a research site. With
the availability of contaminant exposure to students working in the area, current metal
concentrations will be compared to established SCTL concentrations. In doing so,
possible problematic areas can be identified and addressed accordingly. Additionally,
these values may be applied to evaluate potential contamination concerns
for wildlife.
Objective 3 – Comparison of Current Metal Concentrations in Basin Soils to Soil QualityAssessment Guidelines
As the basin ages, a diverse aquatic community is expected to thrive within the
wetland zones. The stability of this aquatic community relies upon its surrounding
environment. The SQAG’s establish concentration ranges for contaminants to evaluate
the possible adverse health effects that these ranges may pose upon the aquatic
community. Areas of concern can be delineated and marked for further studies in
bioavailability and accumulation.
43
As previously stated, the objectives of this research were set to provide the
University of Florida with accurate information on existing soil quality in the NATL
stormwater retention basin. Information obtained through this research can be used in
determining the future direction in which the management and usage of the basin may
proceed.
44
MATERIALS AND METHODS
Site Description
The study site was the retention basin at the Natural Area Teaching Lab (NATL),
located on the campus of the University of Florida. The NATL is located at the
southwestern corner of the University campus (Figure 7). This location affords
individuals an excellent opportunity to conduct field studies of multiple ecosystems. The
outdoor research facility consists of a total of 18.62 ha. Lying within this property are
three upland communities; hammock, upland pine, and old field succession, as well as
thriving wetland communities surrounding both a small sinkhole and the ecologically
enhanced retention basin (Figure 8).
Figure 7. Location of Retention Basin at Natural Area Teaching Lab
45
Figure 8. Layout of Natural Area Teaching Lab
Nine departments in four colleges have dedicated studies involving areas of the
NATL (Wetlands Club, 2001). Included also, is the Wetlands Club, which has
coordinated with the NATL Advisory Committee and the UF Physical Plant to develop
what has now come to be known as the Stormwater Ecological Enhancement Project
(SEEP). The idea for the SEEP was to create a multi-stage wetlands designed not only to
treat and dispose of urban stormwater runoff, but to create desirable conditions that
would attract and sustain various wildlife species. Additional benefits derived from the
development of the SEEP project include:
1) An increase in the overall aesthetics of the NATL
N
46
2) Expanding research opportunities to individuals interested in wetlands study
3) Affording students as well as the public the chance to study wetland systems
in a formal class setting or, by independent viewing.
The stormwater basin is a 1.21-hectare retention pond, which collects runoff from
a number of sources existing within the 40-hectare watershed that it serves. Natural
runoff from the surrounding undeveloped areas becomes mixed with runoff from the
watershed’s impervious surfaces that is transported through an underground network of
piping (Figure 9).
Figure 9. Photograph of stormwater runoff collection area covered with debris.
Of the approximately 41% impervious surfaces existing within the basin, the most
intensive and probable source for pollutant transport comes from parking surfaces,
47
particularly an 1100-space commuter lot to the north, and parking for the
Entomology/Nematology building to the east (Figure 10)
Figure 10. Natural areas and parking surfaces draining to the retention basin. A)Transition area from old field succession to upland pine. B) Southerly view of commuterparking lot and garage. C) Entrance to Entomology & Nematology building located tothe east of the stormwater retention basin.
The basin was originally constructed in 1988 with permitted storage capacity
designed to accept and dispose of 18,855 m3 of stormwater runoff through infiltration and
evaporation. The collection period based on a 100-year flood event based over a 24-hour
A)
B)
C)
48
span. Urban development within the watershed required that the basin be redesigned in
1990 to handle an additional 12,221 m3 of runoff, bringing its total capacity to 31,076 m3.
Design of the basin was traditional in its approach. The lack of surface water
discharge negated the use of a detention system to improve water quality of the disposed
stormwater, allowing for stormwater retention to be the driving force in design. With
retention basins that do not discharge to surface waters, there is greater emphasis on
storage of runoff as opposed to enhanced stormwater treatment. This particular design
was typical of a standard retention basin, dependent upon evaporation and percolation to
dispose of stormwater on-site. Uniform slopes lined the basin to the north, south, and
east, while the west side was contoured to a natural depressional area. Stormwater
entered the system through four major collection sites and was guided to the flat center of
the basin for disposal (Figure 11).
With the concept of the SEEP, basin design became more ecologically enhanced
by the addition of berms in the northern and southeastern portion of the retention basin
and by creating deep water infiltration ponds to the south (Figure 12). Functionality of
the basin shifted from a pure retention type system to a system incorporating retention
theory, using both vegetation and increased water detention periods in conjunction with
on-site disposal.
49
Figure 11. Original design of stormwater retention basin before enhancement projectbegan. A) Stormwater inlet collecting discharge from commuter lot and garage. B)Stormwater inlet collecting runoff from Entomology & Nematology building. C)Stormwater inlet collecting runoff from behind and adjacent to Florida Museum ofNatural History, and the Performing Arts Center. D) Stormwater inlet collecting runofffrom unpaved parking lot and grass swales behind and to the west of the Entomology andNematology building.
A) B)
C)D)
N
50
Figure 12. Diagram of the retention basin post enhancement that occurred in 1998.Berms added to the north and southeast sections of the basin increase and directstormwater flow. The two infiltration ponds to the south allow for increased settling ofstormwater particulate matter and evaporation.
Berm
Berm
Deep WaterInfiltrationPonds
N
51
Sampling Locations
When developing a soil sample scheme for the stormwater management
system, the first step was to separate the basin into individual cells. Each cell could be
evaluated for contamination and comparative values would exist between each region.
The existing configuration of the stormwater basin dictated a division of three cells for
evaluation (Figure 13).
Figure 13. Breakdown of the sample cells inside the stormwater retention basin.
Cell 1
Cell 2
Cell 3
N
52
Cell one represented the forebay, extending from the north end of the basin to the
northern berm, including three of the four stormwater inflow pipes. Cell two
encompassed the remaining stormwater inflow pipe located at the southeastern corner of
the basin and extended to the southernmost section of the berm bordering cell one. Cell
three, the final section of the stormwater management system, consisted of the two deep-
water ponds.
Cell one was further separated into three sections for evaluation. The first
section, located in the northwestern corner of the stormwater management system,
contained two of the three stormwater inflow pipes, which drained the entire impervious
surface of the major parking area. Flow patterns were established through observed
channeling from the inflow areas, and five locations, A1 through A5, were sampled
(Figure 14). The emphasis on these sites was to determine soil quality from the
stormwater inflows to the center of the forebay. All the sites chosen in this area consisted
of soils that had been left undisturbed during re-contouring.
The second section of cell one consisted of a single point just west of the
stormwater inlet pipe located in the northeastern part of the basin. This point, labeled A6
(Figure 14), represented undisturbed basin soils to the east of center in the forebay.
Flows in this area were made up of sheet flow from a two-lane road and parking lot
runoff from the front section of the Entomolgy/Nematology building.
The third section of this cell was the center of the forebay. The majority of this
area, represented by sites A7 through A12 (Figure 14), was scraped during the 1998 re-
contouring. However, site A9, located in the northern part of this section appeared not to
have been disturbed based on the surface texture, and from a visual inspection of the site
53
after the re-contouring. Sample site locations within this section represented contaminant
and suspended particle movement from the stormwater inflows through the forebay,
exiting from the weir into cell two.
In cell two, five sample locations were chosen for evaluation. Sites B1, B2, & B3
(Figure 14) were located south of the weir in an area that had been scraped in 1998. This
represented water flow movement as it entered into cell two, dispersing either south,
southeast, or southwest. A major decision for choosing these points is that soil quality
can be compared between their locations and site A7 to evaluate the efficiency of the
forebay in pollutant removal. Site B4 was situated in the direct flow path coming from
the remaining stormwater inlet pipe to the southeast of the basin. Water flow in this area
was channeled towards the deep-water infiltration ponds by the southern berm and
several small elevated mounds. The soil surface in this area had again been scraped in
1998. The remaining site in cell two, B5, was located in the western portion of the basin.
This area had not been re-contoured in 1998 and was the only section consisting of
original undisturbed soil in cell two.
In cell three, two locations were chosen for evaluation (Figure 14). Site C1 was
located in the center of the first deep-water pond, while C2 was centered in the
southernmost deep-water pond. Due to the need to restructure the infiltration ponds when
creating the SEEP, the entire area within this cell had been re-contoured. An additional
sample, D1, was taken from outside the stormwater management system to act as a
control site. This site was located to the west of the system, directly behind the
Performing Arts Center.
54
Figure 14. Location of sample sites in the stormwater retention basin.
A12A11 A10
A9
A8
A7 A6
A5A4A3
A2
A1 B1
B2B3
B4
B5
C1
C2
D1
N
10m
55
Secondary consideration was given to sample site locations for the evaluation of
soils left in place from the original construction of the stormwater management system,
as compared to soils from the recently re-contoured areas (Figure 15). Eight of the 19
sites within the basin were located in areas left undisturbed, allowing for evaluation and
the creation of baseline data for undisturbed and scraped areas (Table 4).
Figure 15. Sample site locations for the stormwater management system. Areas outlinedin red contain soils left undisturbed during the 1998 re-contouring of the system.
A 12A 11 A 10
A 9
A 8
A 7 A 6
A 5
A 4A 3
A 2
A 1 B 1
B 2B 3
B 4
B 5
C 1
C 2
D 1
N10m
56
Information gathered from the 20 sample sites selected has been used to set
baseline data for future studies at this site. From the locations selected, a good
representation of the extent of contamination within the basin already can be seen, and
some assumptions made based on current soil quality conditions.
Table 4. Sample site status for each cell evaluated.
C ell S ite L o catio n S crap ed / U nd isturb edA 1 U nd isturb edA 2 U nd isturb edA 3 U nd isturb edA 4 U nd isturb edA 5 U nd isturb edA 6 U nd isturb edA 7 S crap edA 8 S crap edA 9 U nd isturb edA 1 0 S crap edA 1 1 S crap edA 1 2 S crap ed
B 1 S crap edB 2 S crap edB 3 S crap edB 4 S crap edB 5 U nd isturb ed
C 1 S crap edC 2 S crap ed
2
3
1
57
Field Procedures
Samples were taken using the guidelines set forth in the Comprehensive Quality
Assurance Plan of the Southwest Florida Water Management District, (1993). All soil
samples were collected with shovels and stainless steel equipment. Soils surfaces, that
came into contact with steel equipment, were removed through the use of non-metallic
spatulas. All loose debris not affixed with the soil was remove before sampling. Coring
devices and spatulas were cleaned with distilled water after each core sample was
completed. Once obtained, samples were stored on ice until transfer was complete to the
University of Florida Environmental Pedology lab. Composite samples of 4 to 7 cores
within an area of 0.25m for each site were analyzed at depths of 0-5cm and 5-10cm.
In all, 20 sites were selected, bringing the total number of analyzed soil samples
to 40. Of the 20 sites, 19 (A1 – A12, B1 – B5, C1 – C2) were located inside the
stormwater management system, with one (D1) being taken outside the system to
represent background data.
Laboratory Procedures
All samples were prepared by first air drying and then running through a 2.0 mm
sieve before ball milling to achieve a homogeneous mixture. Samples were analyzed for
heavy metals, organic carbon content, organic matter content, pH, and particle-size
distribution (Table 5).
58
Table 5. Sediment analysis and methods used in study
Metal Analysis
The heavy metals selected for analysis were chosen based on their rank as the
most common determined in urban stormwater runoff during a 1995 DEP study of
contamination in 87 stormwater management facilities (Livingston, et al., 1995). The
specific metals analyzed were Cd, Cr, Cu, Pb, Ni, and Zn.
A one-gram sample digestion of dried soil was completed at the UF Soil
Environmental Pedology Lab using EPA Method 3050, as directed under the standard
operating procedure guidelines set by UF Professor, Dr. Lena Ma. Sample solutions were
then placed in standardized containers and sent to the Analytical Research Laboratory,
located on the University of Florida campus for analysis by an Inductively Coupled
Plasma (ICP) analyzer. Minimum detection limits for all metals was 0.01 mg/kg, with
the exception of Cr, which was 0.04 mg/kg.
Organic Carbon Content
The organic carbon analysis was completed using the Walkley-Black method.
Samples which exceeded the acceptable range for percent organic carbon using this
method were run again by lowering the samples size to 0.125g or 0.025g, making the
SOIL ANALYSIS METHODMetals (Cd, Cr, Cu, Ni, Pb, Zn) Digestion - EPA 3050
Analysis - Inductively Coupled Plasma (ICP)
Organic Carbon Content Walkey-Black Method(Soil Survey Laboratory Methods Manual, 1996)
Soil Organic Matter Loss On Ignition (Broadbent, 1953)
Particle Size Distribution Pipette Method (Day, 1965)
Soil pH Soil Survey Laboratory Methods Manual (1996)
59
appropriate calculations to obtained percent organic carbon. While the Walkley-Black
method works well on soils with less than 6% organic matter, the loss on ignition method
better suits soils with organic matter contents greater than 6% (Agvise Laboratories,
2002).
Organic Matter Content
To determine organic matter content, the loss on ignition method, as described by
Broadbent (1965), was used. Three grams of soil were placed into 20 ml crucibles and
brought to a temperature of 105ºC for 2 hours. Samples were then weighed to
+0.01grams, then brought to a temperature of 500ºC for a period of eight hours. After
being allowed to cool in a moisture-free environment using a desiccator, the samples
were again weighed and recorded. To determine the percent organic matter the following
equation was used:
% Organic Matter =(Sample Weight 105ºC – Sample Weight 500ºC x 100) / Sample
Weight 105ºC
Particle-Size Distribution
Particle-size distribution was determined on the samples using the pipette method
as described by Day (1965). Since the clay content of these samples was unknown, a
sample weight of 25.0g (+/- 0.1g) was used. Values obtained were compared with a soil
texture classification triangle to determine the appropriate textural class.
pH Analysis
Stormwater retention basin soils were analyzed for pH using the method
described in the Soil Survey Laboratory Methods Manual (1996). Twenty five grams of
soils was analyzed using both water and potassium chloride.
60
Statistical Methods
Statistical analysis was done using the Number Cruncher Statistical
System (NCSS) data analysis software program. Linear regression analysis was
conducted to examine relationships for all dependent variables (metals) to the
independent variables, pH, organic carbon, organic matter, and percent clay content.
Estimating Metal Loading Rates
Analytical data presented in this thesis has indicted that metal concentrations at
certain locations within the stormwater retention basin exceed several indirect guidelines
for soil clean-up and quality assessments. At what point soils within this and similar
basins reach potentially toxic levels is unclear, without regulatory requirements for
periodic soil monitoring. If certain information is known about a particular basin, then
estimates can be made as to a particular concentration of contaminant loading.
For this study, water quality data was not collected, ruling out the option for site
specific loading rates. There are, however, ways to determine rough estimates of metal
loading based on computer-generated programs. One such program is the Long-Term
Hydrological Impact Analysis (L-THIA) GIS – based model. This analysis uses
established hydrologic data, based on a long-term average in combination with defined
land use and soil classes to establish stormwater runoff rates. When site specific data
relating to stormwater metal concentrations is not used with this model, non-point source
pollutant averages established by the Texas Natural Resource Conservation Commission
(TNRCC) becomes the default.
Arial photography was used to create a land-use layer for the SEEP watershed.
The land use and the soils layer will be combined with 20-years of local rainfall data to
61
generate curve numbers and runoff volumes on a one-meter cell grid. L-THIA then
averages these volumes and calculates the average annual runoff volume for each of the
one-meter cells in the drainage basin. These volumes are summarized for each land use
class and combined with runoff coefficients for each metal based on those land use
classes. The total average annual loading of each metal on the SEEP can then be
calculated. These loading rates can be used to place in context the concentrations of
metals found in SEEP soils.
62
RESULTS
The initial objective of this study was to analyze current soil conditions within the
SEEP located at the NATL. Since limited soil data exists for this area, evaluating
parameters such as organic carbon content, organic matter content, pH, and particle-size
distribution may lay the foundation for establishing baseline standards for future studies
at this site.
Urban development of adjacent land within the watershed has required
improvements and upgrades to the stormwater basin, altering soils from their original
pedogenic stages. Soil dating back to the initial construction of the basin indicate soils
not representative of what can be identified today.
Just as important as the altering of soils within the basin for stormwater runoff
collection, are the effects that outside inputs carried in stormwater can have on the
environmental quality of the system. Pollutants, such as heavy metals in stormwater
runoff, may interact differently in soil depending upon soil characteristics.
While it is not uncommon to detect various heavy metals in soils through either
natural deposition or anthropogenic processes, concentrations should be maintained at
levels acceptable to the environment. Metal concentrations of the soils inside the
stormwater retention basin were compared to baseline concentrations for Florida surface
soils established by Chen et al, (1999). Additionally, indirect comparisons were made
with the screening levels referenced by the SQAGs, and the SCTLs.
63
Organic Matter Content
Soils within the stormwater basin were analyzed for percent organic matter at
both 0-5cm and 5-10cm depths (Figure 16). The results indicated the highest organic
matter values in cell 1, within the heavily vegetated northwestern corner of the wetland
basin, sites A1 through A5. At these locations, percent organic matter ranged from 2.7%
to 22% in the upper 5cm samples with an average of 11.3%. The 5-10cm samples ranged
between 1.7% and 21%, averaging 7.7%. The remaining seven sites in cell one ranged
from 2% to 7%, averaging 4.5% in the upper samples, and from 1% to 5.3%, averaging
3.9% in the 5-10cm samples.
In cell 2, percent organic matter ranged from 5.1% to 7.1% in the 0-5cm samples
with an average of 6.0% within the cell. The 5-10cm samples ranged from 5.1% to 7%,
averaging 5.7%. Four of the five sites evaluated in this cell had been previously scraped
during the 1998 re-contouring of the stormwater basin. Excavation at these sites had
removed what little sandy deposits that may have been present, exposing the argillic
horizon to the surface.
Samples taken in cell 3 were limited to two locations, C1 and C2, both scraped
during 1998 construction and redesign of the basin. Percent organic carbon in the 0-5cm
samples was 11% and 8% respectively, and 7% and 8.3% in the 5-10cm samples. The
slightly higher averages for this cell in relationship to cell 2 may be explained by a thin 2
cm biomat that had formed in the dry pond region.
Additional analysis for organic matter content was completed on the control
sample located outside the basin, site D1. At this location, the upper limit sample had a
concentration of 3.6% organic matter, and the lower sample depth was 2.6%. A complete
list of organic matter contents for all of the sample locations are shown in appendix C-4.
Cell 1 Cell 2 Cell 3
0
5
10
15
20
25
A1 A2 A3 A4 A5 A6 A7 A8 A9 A10
A11
A12
B1 B2 B3 B4 B5 C1 C2
Site Location
0-5cm5-10cm
Figure 16. Percent organic matter in soils within the stormwater retention basin.
% O
rgan
ic M
atte
r
64
65
Organic Carbon Content
Quantitative limitations of the Walkley-Black method created a data gap for
several sites where organic carbon content was above the upper limits of detection (6%).
Specifically sites A2, A3, & A5 could not be evaluated. For the remainder of the basin,
percent organic carbon ranged from 0.11% to 4.19%, with highest values in cell 1. There
were five sites within cell 1 that had a percentage greater than 1%; site A1(0-5cm) 1.5%,
site A4(0-5cm) 2.3% and (5-10cm) 1.1%, site A6(0-5cm) 4.1%, site A10(0-5cm) 3.5%,
and site A11(0-5cm) 4.2%. There was only one other site where percent organic carbon
exceeded 1%, which was C1 (0-5cm) at 1.7%. At the control site, percent organic carbon
was calculated to be 0.78% in the in the 0-5cm sample, and 0.75% in the 5-10cm sample.
The higher than expected percentages of organic carbon determined to be present
in these soil samples, may indicate complete oxidation of organic material was not have
been achieved. Thus, values obtained for percent organic carbon may be considered
marginal quantitative data at best. A complete list of percent organic carbon results are in
appendix C-4.
Soil pH
Soil pH was analyzed in both water and potassium chloride for all the sample
sites. The results for water analysis and presented in this study (Figure 17). For this
analysis, four locations, including the northwestern corner of cell 1, the remainder of cell
1, cell 2, and cell 3, will be separated for discussion.
In the northwestern corner of cell 1, the pH ranged from 7.3 to 8.3 in the 0-5cm
samples. The 5-10cm samples had a pH range of 7.2 to 7.8. The pH values in this
section were higher than in any other part of the basin. A possible source of this pH
66
increase could be coming from limestone particulates that have been washed into the cell
from road runoff. In the remainder of cell 1, the 0-5cm samples had a pH range from 5.9
to 7.2. The 5-10 cm samples had a pH range of 5.5 to 6.8.
In cell 2, the 0-5cm samples had a pH from 5.1 to 7.1. The 5-10cm samples had a
pH range of 5.1 to 7.0. The 2 sites in cell 3 had a pH range of 6.7 to 7.0 in the 0-5cm
sample, and a range of 5.3 to 6.8 in the 5-10cm sample. The pH for the control sample
was 6.1 in the 0-5cm depth, and 6.2 in the 5-10cm sample. The data for pH can be found
in appendix C-4.
0123456789
A1 A2 A3 A4 A5 A6 A7 A8 A9 A10
A11
A12
B1 B2 B3 B4 B5 C1 C2
Site Locations
pH
0-5cm Sample 5-10 cm Samples
Cell 1 (NW Section) Cell 1 (Center & NE Section) Cell 2 Cell 3
Figure 17. Soil pH at locations within the stormwater retention basin.
67
68
Particle-Size Distribution
Percent sand, silt, and clay were determined and compared to the soil textural
triangle to establish a major texture class for each sample. Also, field texturing was
conducted at each site using the “feel” method described in Brady (1999). Values are
reported at all locations with the exception of sites A4 and B4, where laboratory error
gave invalid results. The following breakdown of cells describes the soil textures as
determined by the particle-size distribution.
For the purpose of study, soil analysis in the stormwater basin was separated into
four areas: the northwest corner of cell 1, the center and eastern portion of cell 1, all of
cell 2, and all of cell 3. The major textural classes in the northwestern portion of cell 1,
sites A1 through A5, were determined to be sandy and loamy materials. Analysis
indicated that 4 of the 5 surface samples in this location were classified as sands, with the
remaining site, A3, texture a loamy sand. The subsurface samples ranged from sand to a
loam texture. All of these site locations were in areas where no recent scrapping had
occurred.
In the remaining locations of cell 1, A6 through A12, surface textures varied from
loamy sand to sandy clay loam. The sandier locations were represented by sites A6 and
A9, which were not scraped during the re-contouring of the SEEP. Loamy sand extended
into the 5-10cm depth at each of these locations. The remaining sites within cell 1 had
been scrapped down to the argillic horizon, leaving a sandy clay loam present at the
surface, extending through the 5-10cm sample.
The majority of sites sampled within cell 2 were of similar texture class as those
identified in the center of cell 1. The surfaces for sites B1 through B4 had been removed
69
during redesign of the basin, exposing finer textured sandy clay loam material. Site B5 in
the westerly region of this cell, however, had remained untouched, leaving sandy to
loamy sand textured material.
Cell 3 had been entirely reworked as part of the plan to enlarge and deepen the
ponds to the south of the retention basin. Excavation in this area completely removed
any of the sandier textured soils down to the argillic horizon. Both sites evaluated in cell
3 fell within the textural triangle as either sandy clay loam or sandy clay. The control site
soils were classified as sands in both the 0-5cm sample and the 5-10cm sample. Data for
the particle-size distribution in the basin soils is listed in appendix C-1.
Metals: Cadmium
Cd vs. Baseline Concentration Levels
Cd was detected at 5 of 19 soil sample locations within the stormwater retention
basin. Concentrations in the 0-5cm samples ranged from 0-2.5 mg/kg and were identical
in the 5-10cm sample depth. Detection above the upper limit of the baseline
concentration range occurred in 4 of the 0-5cm samples and in 2 of the 5-10cm samples
(Figure 18). Three of the sites where detection occurred were within the initial treatment
zone, cell 1. The two remaining sites were split between cell 2 and cell 3. The sites
where Cd was present were above the baseline concentration range of 0-0.33 mg/kg as
established for Florida surface soils (Chen et al., 1999). Cd was not detected in the
control site sample located outside the retention basin.
Cd Concentrations Compared With Various Screening Levels
Of the 5 sites where Cd was detected, concentrations at three locations, all in cell
1, were above the TEL of 0.676 mg/kg established by the SQAGs (Figure 19). There
70
were no exceedences for PELs of 4.20 mg/kg, or the SCTLs residential and commercial
based values of 75 mg/kg and 1300 mg/kg respectively (Figure 20).
������������������������������������������������� ������������������������������������ ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ ������������������������������������������������ ������������������������������������ �����������������������������������0
0.5
1
1.5
2
2.5
3A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12 B1
B2
B3
B4
B5
C1
C2
Site Locations
Cadmium Concentration (mg/kg)
0-5cm
5-10cm
0-0.33 mg/kg Baseline Concentration
Figure 18. Cadmium concentrations in the stormwater basin soils. The baseline concentration range for cadmium in Florida surfacesoils is represented by the red shaded region..
71
72
A12A11 A10
A9
A8
A7 A6
A5A4A3
A2
A1 B1
B2B3
B4C1
C2
D1
Figure 19. Location of sites where cadmium concentrations were detected abovethreshold effects levels (TELs) derived by the soil quality assessment guidelines. Sitesabove TELs are shaded in yellow.
N
10m
B5
��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ����������������������������������������������������������������������������������������������������������������������������������� ���������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������
��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ���������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������0
0.5
1
1.5
2
2.5
3
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12 B1
B2
B3
B4
B5
C1
C2
Site Locations
Cadmium Concentration (mg/kg)
0-5cm
5-10cm
0.676 mg/kg TEL
Cell 1 Cell 2 Cell 3
Figure 20. Comparison of cadmium concentrations to screening criteria throughout the entire basin. These concentrations wereevaluated at depths of 0-5cm and 5-10cm. Exceedences of screening criteria occurred for the threshold effects level (TEL) derived bythe soil quality assessment guidelines (SQAG’s).
73
74
Metals: Chromium (Cr)
Cr vs. Baseline Concentration Levels
Cr was detected at all 19 sites within the stormwater retention basin with
concentrations ranging from 21.0 -262.5 mg/kg in the 0-5cm samples and from 12.0-180
mg/kg in the 5-10cm samples. When compared to baseline concentration data there were
4 sites that exceeded the established range of 0.89-80.7 mg/kg (Figure 21). These sites
were located in cell 1, to the northwest corner of the retention basin. The highest
concentrations of Cr in these areas were detected in the 0-5cm samples, with baseline
exceedences in the 5-10cm samples occurring at only 2 of the 4 locations. When
comparing elevations of Cr in the control sample, they fell within established baseline
concentrations at both the 0-5cm sample (20.5 mg/kg), and the 5-10cm sample (23.5
mg/kg).
Cr Concentrations Compared With Various Screening Levels
Cr concentrations were compared to the derived protection levels established
under the SQAGs. Exceedences of TELs set at 52.3 mg/kg occurred at 4 sites within cell
1 to the northwest corner of the retention basin (Figure 22). Levels of concern extended
into the 5-10cm depths at 2 of the locations. Additionally, concentrations of Cr were
high enough at these same 4 sites to exceed the PEL of 160 mg/kg, although, only one
site showed a PEL exceedence at a 5-10cm depth.
When comparing the data to the SCTL residential and commercial toxicity values,
2 sites contained Cr concentrations above the SCTL residential value of 210 mg/kg. The
concentration of Cr above SCTLs did not extend to the 5-10 cm depth. There were no Cr
concentrations above the SCTL commercial-based values of 420 mg/kg. Concentration
75
of Cr in the 5-10cm samples exceeded levels in the 0-5cm samples at 6 of the 19
locations within the basin (Figure 23).
����������������������������������������������������������������������������������������������������������������������������������������� ������������������������������������������������������������������������������������������������������ ���������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ���������������������������������������������������������������������������������������������������������������������������������������� ������������������������������������������������������������������������������������������������������ �������������������������������������������������������������������0
50
100
150
200
250
300
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12 B1
B2
B3
B4
B5
C1
C2
Site Locations
Chrom
ium Concentration (mg/kg)
0-5cm
5-10cm
0.89 - 80.7 mg/kg Baseline Concentration Range
Figure 21. Chromium concentrations in the stormwater retention basin soils. The baseline concentration range for chromium inFlorida surface soils is represented by the red shaded region
76
Figure 22. Location of sites where chromium was detected above contaminant screening levels. (A) Sites exceeding threshold effectslevels (TEL’s) as established by the soil quality assessment guidelines (SQAG’s) are shaded in yellow. (B) Sites exceeding probableeffects levels (PEL’s) as established by the SQAG’s are shaded in red. (C) Sites exceeding soil cleanup target levels (SCTL’s)established in Chapter 62-777, Florida Administrative Code. Sites shaded in orange represent residential toxicity value exceedences(RTV’s).
A12A11 A10
A9
A8
A7 A6
A5
A4A3
A1
A2
B1
B2B3
B4C1
C2
D1
B5
A
A12A11 A10
A9
A8
A7 A6
A5
A4A3
A1
A2
B1
B2B3
B4C1
C2
D1
B5
B
A12A11 A10
A9
A8
A7 A6
A5
A4A3
A1
A2
B1
B2B3
B4C1
C2
D1
B5
C
N
20m 20m 20m
N N
77
������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ �����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������
������������������������������������������������������������������������������������������������������������������������������������� ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ ������������������������������������������������������������������������������������������������������������������������������������ �����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������
������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������0
50
100
150
200
250
300
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12 B1
B2
B3
B4
B5
C1
C2
Site Locations
Chrom
ium Concentration (mg/kg)
0-5cm
5-10cm
52.3 mg/kg TEL
160 mg/kg PEL
210 mg/kg SCTL RTV
Cell 1 Cell 2 Cell 3
Figure 23. Comparison of chromium concentrations to screening criteria throughout the entire basin. These concentrations wereevaluated at depths of 0-5cm and 5-10cm. Exceedences of screening criteria occurred for the threshold effects levels (TEL's) andprobable effects levels (PEL’s) established by the soil quality assessment guidelines. Additionally, concentrations exceeded soilcleanup target levels (SCTL’s) for residential values (RTV’s). Concentrations of chromium in the 5-10cm depth samples exceededthe concentrations in the 0-5cm sample depths at 5 of the 19 sample site locations.
78
79
Metals: Copper (Cu)
Cu Vs. Baseline Concentration Levels
Cu concentrations were detected at all 19 sites within the stormwater retention
basin. Levels ranged from 5.5-235 mg/kg in the 0-5cm sample depths and from 3.0-102
mg/kg in the 5-10cm samples. Seven sites exceeded the upper limit of the baseline
concentration range (Figure 24). Similar to both Cd and Cr, exceedences were observed
in the northwest corner of cell 1. Elevated levels were also documented at three other
locations within cell 1, including the highest concentration at the northeastern stormwater
inlet, and at one location in cell 3. In 18 of the 19 sites the 0-5cm sample depths
contained a higher concentration of Cu, with the one exception being site A2. This was
also the only location where the 5-10cm sample depth exceeded the baseline range upper
limit. Cu concentration in the control sample was at 3.0 mg/kg at both depths, which falls
within the established baseline range.
Cu Concentrations Compared With Various Screening Levels
The SQAGs have a derived TEL for copper of 18.7 mg/kg. Cu concentrations in
the soils of the retention basin exceeded TELs at 8 sites. Seven of these sites were
located in cell 1, with the remaining site located in cell 3. Two of the sites had levels of
Cu in concentrations higher than the PEL of 108 mg/kg. Each of these two locations
were in direct flow from the stormwater inlets to the northwest and northeast areas of cell
1.
The SCTLs have established exposure protection limits from Cu for residential
and commercial applications of 110 mg/kg, and 76,000 mg/kg, respectively. Residential
exposure concentrations were exceeded at the two sites in direct flow from the inlets in
80
cell1 (Figure 25). Cu was not detected at levels exceeding the commercial based values
established by the SCTLs.
As indicated with the comparison to the baseline concentration range,
concentrations of Cu in the 5-10cm depth samples tended to be lower than in the upper
sample. Of the 7 sites where Cu was detected above screening levels, exceedences in the
5-10cm sample depths occurred at only one site (Figure 26). This was consistent with the
entire basin.
����������������������������������������� ������������������������������ ���������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ���������������������������������������� ������������������������������ �������������������0
50
100
150
200
250
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12 B1
B2
B3
B4
B5
C1
C2
Site Locations
Copper Concentration (mg/kg)
0-5cm
5-10cm
0.22 - 21.9 mg/kg Baseline Concentration Range
Figure 24. Copper concentrations in the stormwater retention basin soils. The baseline concentration range for copper in Floridasurface soils is represented by the red shaded region
81
Figure 25. Location of sites where copper was detected above contaminant screening levels. (A) Sites exceeding threshold effectslevels (TEL’s) as established by the soil quality assessment guidelines (SQAG’s) are shaded in yellow. (B) Sites exceeding probableeffects levels (PEL’s) as established by the SQAG’s are shaded in red. (C) Sites exceeding soil cleanup target levels (SCTL’s)established in Chapter 62-777, Florida Administrative Code. Sites shaded in orange represent residential toxicity value exceedences(RTV’s).
A12A11
A10
A9
A8
A7 A6A5A4A3
A1
A2
B1
B2B3
B4C1
C2
D1
B5
A
A12A11 A10
A9
A8
A7 A6A5A4A3
A1
A2
B1
B2B3
B4C1
C2
D1
B5
B
A12A11 A10
A9
A8
A7 A6
A5A4A3
A1
A2
B1
B2B3
B4C1
C2
D1
B5
C
N30m
N30m
N30m
82
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������������������������������������������������������������������������������������������������������������������������������������� ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ ������������������������������������������������������������������������������������������������������������������������������������ �����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������
������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������0
50
100
150
200
250
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12 B1
B2
B3
B4
B5
C1
C2
Site Locations
Copper Concentration (mg/kg)
0-5cm
5-10cm
18.7 mg/kg TEL
108 mg/kg PEL
110 mg/kg SCTL RV
Cell 1 Cell 2 Cell 3
Figure 26. Comparison of copper concentrations to screening criteria throughout the entire basin. These concentrations wereevaluated at depths of 0-5cm and 5-10cm. Exceedences of screening criteria occurred for the threshold effects levels (TEL's) andprobable effects levels (PEL’s) established by the soil quality assessment guidelines. Additionally, concentrations exceeded soilcleanup target levels (SCTL’s) for residential values (RTV’s). Concentrations of copper in the 5-10cm depth samples exceeded theconcentrations in the 0-5cm sample depths at only one site within the basin.
83
84
Metals: Lead (Pb)
Pb Vs. Baseline Concentration Levels
Concentrations of Pb were detected in soils at all 19 sites within the retention
basin. Concentrations in the surface samples ranged from 7.0-61.0 mg/kg, and from 0.5-
64.5 mg/kg in the 5-10cm depth samples. When compared the baseline concentrations, 2
sites exceeded the upper limits of the concentration range established at 0.69-42.0 mg/kg.
Both locations were in cell 1 at the northwestern corner of the basin. Exceedences
occurred in the upper samples at both locations and in the 5-10cm sample at one site
(Figure 27). Pb concentration in the control samples was at 4.5mg/kg and 5.0 mg/kg in
the 0-5cm sample and the 5-10cm sample respectively.
Pb Concentrations Compared With Various Screening Levels
The concentrations of Pb in soils were compared to screening levels established in
the SQAGs and the SCTLs. The SQAGs have derived a protection value of 30.2 mg/kg
as a TEL for Pb in sediments. Basin soils exceeded this value at 4 locations, 3 of these
sites being located in the northwestern corner of cell 1, and one site on the northern end
of cell 3 (Figure 28). Exceedences occurred at the 0-5cm sample depth in 2 of the 3
locations in cell 1, and in the lone location in cell 3. Pb concentrations in the 5-10cm
samples exceeded TELs at 2 locations in cell 1 only. When evaluating the entire basin,
Pb concentrations in the 5-10cm samples exceeded the upper 0-5cm samples at 5 of 19
sites, or 26% (Figure 29). Pb did not exceed the PEL of 111.9 mg/kg or SCTLs for
residential (400 mg/kg) and commercial (920 mg/kg) exposures.
������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ �����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������0
10
20
30
40
50
60
70A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12 B1
B2
B3
B4
B5
C1
C2
Site Locations
Lead Concentration (mg/kg)
0-5cm
5-10cm
0.69 - 42.0 mg/kg Baseline Concentration Range
Figure 27. Lead concentrations in the stormwater retention basin soils. The baseline concentration range for lead in Florida surfacesoils is represented by the red shaded region
85
86
Figure 28. Location of sites where lead concentrations were detected above thresholdeffects levels (TEL’s) derived by the soil quality assessment guidelines. Sites aboveTEL’s are shaded in yellow.
A12A11 A10
A9
A8
A7 A6
A5
A4A3
A1
A2
B1
B2B3
B4C1
C2
D1
B5
N
10m
������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ �����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������
������������������������������������������������������������������������������������������������������������������������������������� ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ ������������������������������������������������������������������������������������������������������������������������������������ �����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������
������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������0
10
20
30
40
50
60
70A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12 B1
B2
B3
B4
B5
C1
C2
Site Locations
Lead Concentration (mg/kg)
0-5cm
5-10cm30.2 mg/kg TEL
Cell 1 Cell 2 Cell 3
Figure 29. Comparison of lead concentrations to screening criteria throughout the entire basin. These concentrations were evaluatedat depths of 0-5cm and 5-10cm. Exceedences of screening criteria occurred for the threshold effects level (TEL) derived by the soilquality assessment guidelines. Concentrations of lead in the 5-10cm depth samples exceeded the concentrations in the 0-5cm sampledepths at 5 of the 19 sites within the stormwater basin.
87
88
Metals: Nickel (Ni)
Ni Vs. Baseline Concentration Levels
Ni concentrations were detected at all 19 sites located within the stormwater
retention basin. Concentrations ranged from 5.5-29.0 mg/kg in the 0-5cm sample depths,
and from 4.0-31.5 mg/kg in the 5-10cm samples. When compared to the Ni baseline
concentration range of 1.70-48.5 mg/kg there were no exceedences of the upper limits
(Figure 30). In the control sample, the 0-5cm sample contained 2.5 mg/kg of Ni, and the
5-10cm sample contained a concentration of 3.0 mg/kg.
Ni Concentrations Compared With Various Screening Levels
When Ni concentrations in the retention basin were compared to the SQAGs, 2
sites had levels elevated above the TEL of 15.9 mg/kg. Both locations were in the
northwest corner of cell 1, adjacent to the stormwater inlets (Figure 31). A third site in
cell 1 had a Ni concentration of 15.0 mg/kg in the 0-5cm sample. Exceedences occurred
in the 0-5cm samples at both locations, and in the 5-10cm sample at one site. There were
no exceedences for the PEL of 15.8 mg/kg, or for the SCTL residential (110 mg/kg) and
commercial (28,000 mg/kg) exposures at any of the sites. When evaluating Ni
concentration throughout the entire retention basin, levels decreased from the upper
samples to the lower depths at 15 of the 19 sites (Figure 32).
��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� �������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������
0
5
10
15
20
25
30
35A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12 B1
B2
B3
B4
B5
C1
C2
Site Locations
Nickel Concentration (mg/kg)
0-5cm
5-10cm
1.70 - 48.5 mg/kg Baseline Concentration Range
Figure 30. Nickel concentrations in the stormwater retention basin soils. The baseline concentration range for nickel in Floridasurface soils is represented by the red shaded region
89
90
A12A11 A10
A9
A8
A7 A6
A5
A4A3
A1
A2
B1
B2B3
B4C1
C2
D1
B5
Figure 31. Location of sites where nickel concentrations were detected above thresholdeffects levels (TEL’s) derived by the soil quality assessment guidelines. Sites aboveTEL’s are shaded in yellow.
N
10m
������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ ������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ �����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������
������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ������������������������������������������������������������������������������������������������������������������������������������ �����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������
������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� �����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������0
5
10
15
20
25
30
35A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12 B1
B2
B3
B4
B5
C1
C2
Site Locations
Nickel Concentration (mg/kg)
0-5cm
5-10cm15.9 mg/kg TEL
Cell 1 Cell 2 Cell 3
Figure 32. Comparison of nickel concentrations to screening criteria throughout the entire basin. These concentrations wereevaluated at depths of 0-5cm and 5-10cm. Exceedences of screening criteria occurred for the threshold effects level (TEL) derived bythe soil quality assessment guidelines. Concentrations of nickel in the 5-10cm depth samples exceeded the concentrations in the 0-5cm sample depths at 2 of the 19 sites within the stormwater basin.
91
92
Metals: Zinc (Zn)
Zn Vs. Baseline Concentration Levels
Zn was detected at all 19 sites within the stormwater retention basin.
Concentrations ranged from 10.5-720 mg/kg in the 0-5cm sample depths, and from 6.5-
558 mg/kg in the 5-10cm samples. When compared to the baseline concentration range
of 0.89-29.6 mg/kg, there were 10 sites that exceeded the upper limit of this range (Figure
33). The 0-5cm samples at these 10 locations were all above the baseline range, and 5 of
these sites contained levels above the range into the 5-10cm sample depths. Seven of
these locations were in cell 1, with the highest concentrations located in the northwestern
corner. One site was in cell 2, and the other 2 were located in cell 3. Zn concentrations
in the control sample were also above the baseline concentration range at 32.5 mg/kg in
the 0-5cm sample depth, and at 35.5 mg/kg in the 5-10cm sample.
Zn Concentrations Compared With Various Screening Levels
The SQAGs have established a TEL for Zn at 124 mg/kg. Concentrations within
the stormwater retention basin exceeded this level at 3 locations in the northwestern
corner of cell 1, adjacent to a major inflow. The levels, which were present at these
locations, also exceeded the PEL for Zn of 271 mg/kg (Figure 34). Levels of Zn above
SQAGs were present in the 0-5cm samples at all 3 locations, but extended into the lower
samples at only one site. There were no concentrations above SCTLs for residential
(23,000 mg/kg) or commercial (560,000 mg/kg) exposures. When looking at all 19 sites
within the retention basin, Zn concentrations decreased from the upper to the lower depth
samples at 18 locations (Figure 35).
Figure 33. Zinc concentrations in the stormwater retention basin soil. The baseline concentration range for zinc in Florida surfacesoils is represented by the red shaded region
������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������0
100
200
300
400
500
600
700
800
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12 B1
B2
B3
B4
B5
C1
C2
Site Locations
Zinc Concentration (mg/kg)
0-5cm
5-10cm
0.89 - 29.6 mg/kg Baseline Concentration Range
93
Figure 34. Location of sites where zinc was detected above contaminant screening levels. (A) Sites exceeding threshold effects levels(TEL’s) as established by the soil quality assessment guidelines (SQAG’s) are shaded in yellow. (B) Sites exceeding probable effectslevels (PEL’s) as established by the SQAG’s are shaded in red.
A12A11 A10
A9
A8
A7 A6
A5
A4A3
A1
A2
B1
B2B3
B4C1
C2
D1
B5
A
A12A11 A10
A9
A8
A7 A6
A5
A4A3
A1
A2
B1
B2B3
B4C1
C2
D1
B5
B
N
20m
N
20m
94
95
Figure 35. Comparison of zinc concentrations to screening criteria throughout the entire basin. These concentrations were evaluatedat depths of 0-5cm and 5-10cm. Exceedences of screening criteria occurred for the threshold effects level (TEL) derived by the soilquality assessment guidelines. Concentrations of lead in the 5-10cm depth samples exceeded the concentrations in the 0-5cm sampledepths at only one of the 19 sites within the stormwater basin.
��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� �������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������
������������������������������������������������������������������������������������������������������������������������������������ ���������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ����������������������������������������������������������������������������������������������������������������������������������� ���������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������
��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� ���������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������0
100
200
300
400
500
600
700
800
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12 B1
B2
B3
B4
B5
C1
C2
Site Locations
Zinc Concentration (mg/kg)
0-5cm
5-10cm
124 mg/kg TEL
271 mg/kg PEL
Cell 1 Cell 2 Cell 3
95
96
Linear Regression Analysis
Linear regression analyses were conducted to determine correlations between
metals and certain soil properties. All metals were regressed on pH, percent clay content,
organic carbon, and organic matter. Variables with significant r2 values and
corresponding p-values were identified and reported.
97
DISCUSSION
This research focused mainly on heavy metal pollutant concentration
identification and the possible threats these contaminants pose to both wildlife and human
communities. The significance of contamination should be measured by its potential to
impact upon an identified community. Through soil analysis, heavy metals were
identified to be present within some soils in the stormwater basin at the NATL.
Upon review of the results for this study, several points of discussion can be made
regarding the current soil conditions and the heavy metal contaminant concentrations
existing within the stormwater management system.
With the exception of Cd, the remaining five metals analyzed were detected at all
19 sites within the stormwater management system, and at the control site outside the
basin. Metal concentrations within the basin exceeded typical background levels for
Florida surface soils at 10 sample locations. The most common metal detected in excess
of background levels was Zn, exceeding background levels at 10 sites, followed by Cu
(7), Cd (5), Cr (4) and Pb (2). The only metal not detected above what was considered to
be baseline concentrations was Ni.
Eight of the 10 sites where background exceedences occurred were at locations
left undisturbed during the 1998 re-contouring of the basin. Sites A1 through A5 were
the most prevelant in containing soils with background exceedences. There were two
locations that had been scraped in 1998, which did show concentrations of Zn, and Cu
above background levels, sites A11 and C1. Both of these locations lay within eight
98
meters of soils left in place from original basin construction. Since they were not within
a direct flow path adjacent to stormwater inflow pipes, contaminant concentrations may
be attributed to either metal release from soils in the older areas or from metal-organic
matter complexes, allowing for smaller particulates to short circuit natural depositional
pathways increasing their mobility.
In addition to its prevalence within the stormwater retention basin, Zn was
detected above background levels in the control sample outside the stormwater collection
area. The reason for this control sample exceedence may be stormwater runoff from
behind the Performing Arts Center. Although runoff from this parking area is directed
towards the stormwater inlet in cell 1, heavy rainfall events may allow sheet flow to
discharge in the vicinity of the control sample site location. Other studies have suggested
that Zn in rainfall may contribute directly to levels of Zn within stormwater basins, which
may explain why no other stormwater related metals were exceeding background levels
at the control site (Carr et al., 1995).
Metals were detected at nine sites within the basin at concentrations above TELs,
as established by the SQAGs. The most common exceedence was Cu at 37%, followed
by Pb and Cr at 21%. Cd, Ni, and Zn ranged from 16% to 11% respectively. Six of the
nine locations where TEL exceedences occurred were undisturbed soils that had been in
place since original basin construction. Sites A2 through A5 in the northwestern corner
on the retention basin contained the greatest number of TEL exceedences for each metal.
Other locations included A6 at the northeastern inlet pipe, A12 adjacent to that point, the
northern most point A9, and in two of the re-contoured areas A11 and C1. While TEL
exceedences occurred mainly in the 0-5cm samples, elevated concentration of metals in
99
the 5-10cm samples were detected at the A2 and A5 locations. With A2 being located
directly in the flow path of the main stormwater inlet, and A5 being adjacent to this area
the majority of the stormwater entering the basin would be directed to these locations. It
was noted that the highest organic materials were present in the northwestern corner of
cell 1, which correlated with soils previously not scraped and the greater number of TEL
exceedences.
PEL exceedences occurred at five sites within the stormwater retention basin.
Metals detected above PELs were Cr, Cu and Zn, with four of the 5 sites being located in
the northwestern corner of cell 1, and the remaining site located at the stormwater inlet to
the east of the same cell. All five locations were soils that had been previously left
untouched during the 1998 construction. PEL concentrations extended into the 5-10cm
samples for Cr and Zn at site A2, which again corresponds to high organic concentrations
within both sample depths, and is in direct flow from the major stormwater input.
Cr and Cu were detected at concentrations exceeding SCTLs for residential
exposures as established in Chapter 62-777, F.A.C. Locations of exceedences were
consistent with the TEL concentrations.
From the data analyzed, the concentration of metals in the northwestern portion of
cell 1 was not surprising. This area collects the greatest amount of stormwater entering
the system from the commuter lot and parking garage. The levels at which these metals
were identified were of concern however, since this basin, at 12 years of age, is
considered relatively young.
In addition to the areas of concern for contaminant build-up, it was noted that
during heavy rain events, stormwater runoff entering the system from the southeastern
100
portion of the SEEP was short-circuiting the treatment marsh. As sheet flows increased,
runoff was able to discharge untreated directly to the infiltration pond (Figure 36).
Figure 36. Diagram of the SEEP with areas of concern and short-circuiting pathhighlighted. Area colored in red indicates region where contaminants were detected insoils not scraped during basin re-contouring. Areas colored in green indicatecontamination detected in soils that were scrapped during the recontouring of the basin.The blue arrow indicates stormwater inflow into the basin, short circuiting the treatmentzones.
N10m
101
The identification of elevated levels of metals in the soil, while significant, is only
part of the contaminant equation. To complete the cycle we must know the potential for
a community to be negatively impacted. That potential comes from the concept of the
NATL and the SEEP.
As stated on its website, the NATL is a tract of land dedicated for use as a
teaching facility by the University. Right now the major benefactors are the students at
UF, but, the facility is open to the public. As indicated earlier, nine departments in four
of the Colleges at UF either currently or plan to use the NATL as part of their teaching
curriculum. Data obtained from the NATL website estimates that approximately 2500
UF students will be receiving some type of course work relating to the site. Several of
the Departments have indicated the desire to use the facility for other projects outside the
normal classroom studies, which will increase the number of individuals visiting the area
(Natural Area Teaching Lab, http://natl.ifas.ufl.edu/natluses).
In addition to the input of students from UF, the Florida Museum of Natural
History gives guided tours of the NATL to K-12 students from Alachua and surrounding
counties. The number of these types of visits is around 2400 students per year, and is
expected to grow as the area develops (Natural Area Teaching Lab,
http://natl.ifas.ufl.edu/natluses). These numbers do not include any visitations from the
general public, not associated with the University of Florida. While estimates may reach
over 5,000 people a year visiting the site, the actual number that could access the
stormwater retention basin is unclear.
The research and educational opportunities that the SEEP offers students and
others are not the only planned benefits of this area. In addition, the design of the basin is
102
expected to be beneficial in creating plant diversity, a more diverse wildlife habitat,
improved landscape appearance, and an overall increase in the overall quality of the
stormwater exiting the system. Plantings were made throughout the basin intending to
create species diversity, and let the natural processes of wetlands dictate the vegetative
diversity (Wetlands Club, Undated)
As the vegetative community has developed, wildlife activity in the area has
increased. During the course of this research many different species of the avian
community were noticed, including several species of wading birds, which fed on
organisms or other material in the soils of the basin. Another occupant of the stormwater
basins northwestern corner was an alligator. She nested in the area where the majority of
the elevated metal concentrations were detected.
In an effort to create an aesthetic environment (one of the desired outcomes of the
SEEP) the basin was planted with a variety of species to mimic various wetland
communities. The forebay, where the majority of the stormwater enters the basin, was
planted with species known for their ability to take up metals and nutrients. Additional
design considerations of the basin, including the increased holding times of stormwater
offered in the holding bay, were in place to improve the overall water quality. Although
bio-availability was not assessed in this study, vegetation selection and increased
stormwater retention in combination with the scrapping of soils during re-contouring may
have been a reason that contamination was not seen distributed throughout the entire
basin.
Another factor influencing metal distribution within the stormwater basin may be
the leaching potential of the soils. As determined through soil analysis, the underlying
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horizons in the basin appear to be thick argillic horizons. These clays were additionally
identified in previous soil logs throughout the basin. As organic matter- stormwater
contaminant complexes form, increased retention times may allow for further bonding
between metals with the organic materials and clay minerals.
While the concentrations of metal contaminants within the stormwater basin do
warrant attention, their effects on both human and wildlife species may be limited. As
previously detailed, there are no direct standards that apply to contaminant concentrations
in soils of stormwater retention basins, nor an effective way to regulate any developable
measures. Studies in Florida compare their findings to several regulatory program
guidelines indirectly. Two common references are the SCTLs outlined in Chapter 62-
777, Contaminant Cleanup Target Levels, and the threshold and probable effects levels
described in SQAGs manual.
The SCTL standards are developed for risk assessments based on factors such as
individual body weight, exposure times, and exposure concentrations. One-time visitors
or even researcher doing limited work in the SEEP would be at low risk due to short
exposure time. Another factor influencing risk is that the contamination is basically
limited to a small area within the basin. Identifying these areas may lead too a greater
awareness, and precautionary steps can be taken to limit dermal and inhalation exposures.
The wildcard could be the effects on the vegetative and wildlife communities of the
stormwater basin. With smaller organisms the effects may be magnified to a point where
concentration, exposure time may be decreased for adverse effects to occur.
Use of the SQAGs for defining absolute contaminant issues are limited as well.
These numbers were originally developed for coastal communities. The lack of good
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freshwater data has led researchers to apply these standards indirectly to freshwater
systems anyway. Guidelines for freshwater systems are currently being developed by the
FDEP, but were not available during the course of this study. As stated in the manual,
SQAGs are to be used with factors such as bio-availability studies when determining
aquatic community risk evaluations. There is some evidence, though, that suggests soils
with contaminant concentrations above PELs may pose a threat to the biotic communities
existing within this system (FDEP, 2001). Several areas within the forebay, or cell 1, had
exceedences of PEL’s. The vegetative cover and availability of water in these areas may
make them prime locations for biological activity.
The research completed detected various contaminants at varying concentrations
within the stormwater basin. While the effects of their presence within this system are
not currently known, to ignore their existence could be a mistake. Indirectly applying
regulatory standards for the purpose of environmental assessment studies may be the only
tools available to profile these contaminant concentrations. Removal and remediation of
soils may not always be the most effective measures when addressing this contamination.
Instead, by identifying and detailing contaminant locations, procedures can be put in
place to effectively monitor and manage existing ecosystems.
Simple Linear Regression
Simple linear regression analyses were conducted on the six dependent metal
variables to determine any significant correlation to certain soil characteristics. The
independent soil characteristics used were pH, percent clay, organic carbon, and organic
matter. Cd was not reported due to the limited number of detection sites available.
Initial regressions were run using the entire set of 38 points. From that data set, r2
values obtained were very low for metals regressed with pH, and percent clay content.
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Both Cr and Zn had moderately low r2 values of 0.36 and 0.24 respectively. Upon
reviewing their associated regression curve it was noted that several outliers may have
been influencing their relationships. When these points were removed, the model
lowered r2 in both cases. Organic carbon content initially showed a moderate correlation
to all metals. When analyzing the data set, there were several points where organic
carbon content was not determined, but instead assigned a limited value. The results if
used may poorly reflect the relationships that exist.
The strongest correlation for metal relationships was organic matter. Cr (r2 =
0.48), Ni (r2 = 0.27), Pb (r2 = 0.44), and Zn (r2 = 0.34), showed influence from organic
matter content with n = 38. Recognizing that 2 separate population may exist with th 0 –
5 cm samples and the 5 – 10 cm samples, regression r2 = 0.50s were run on both these
data sets. In the surface samples, the r2 increased for Ni (r2 = 0.51), Pb (r2 = 0.50), and Zn
(r2 = 0.47). Cr decreased slightly to a r2 of 0.46. Statistically, the 5 – 10 cm samples had
r2 values below 0.5 with the exception of Cr (r2 = 0.56). Taking the regression one step
further, the 0 – 5 cm samples were run for all locations within cell 1, sites A1 through
A12. Reviewing the regression reports it was noticed that 2 locations within cell 1 may
have been influenced by position within the cell. Using the linear regression model it
appeared both sites lay outside the normal probability plot. When these points, A2 and
A5 were removed, the data set of n = 10 yielded strong r2 values of 0.91 for Ni, 0.93 for
Pb, and 0.79 for Zn. These numbers by far were the strongest of any regression plot run,
indicating organic matter content to be significantly correlated to the presence of Ni, Pb,
and Zn. A complete table with all r2 and p-values can be found in Appendix C.
Additional linear regression analysis curves are listed in Appendix D.
106
Metal Loading Rates
Since no regulations require frequent monitoring of contaminant build-up over
time within stormwater basin soils, it may be difficult to assess at what point these soils
reach potentially toxic levels of metals. A method for estimation could be to take average
concentrations of pollutants over time, combined with rainfall data to estimate total
pollutant loads. This method would not account though for stormwater lost through
infiltration, and could lead to over estimating loading. The option chosen for this
research was to use the L-THIA GIS-based model. Using the L-THIA model, estimated
annual loading rates were established for the SEEP basin. Before loading rates could be
calculated, several steps were first taken.
First, one of the prime components in generating runoff curve numbers in L-
THIA is land use category. Since no land use GIS layer existed that was compatible for
the L-THIA model, it had to be created. To do this, an aerial photograph of the area was
obtained (Figure 36). By examining the photograph areas were designated as either open
land, forested, or impervious surface for compatibility to L-THIA (Figure 37). Once
these land use categories were in place, the total water shed area was designated using
United States Geological Survey quad maps (Figure 38). An existing soil type layer was
added to the map (Figure 39). Using both the land use category, and soil classification
layers, L-THIA generated the SCS curve number for the watershed based on one-meter
cells. The next step was to apply annual rainfall data for the area based on 20-years of
data. These estimates were obtained for Alachua County, and put into the model. L-
THIA now generated estimated runoff from the watershed basin into the SEEP.
Figure 37. GIS photograph of the area adjacent to the stormwater retention basin
107
Figure 38. GIS land use classification designations for the areas surrounding the retention basin.
108
Figure 39. GIS designated land use classes within the retention basin watershed.
109
Figure 40. GIS soils layer added to land use classifications.
110
111
The final part of the equation was to compare metal concentrations in stormwater
with the estimated runoff values generated by L-THIA. Since no site specific stormwater
quality data was collected, the L-THIA default values, obtained from the TNRCC study
were used (Table 6)
Table 6. Metal concentrations in stormwater runoff (Baird and Jennings, 1996)
Metal Commercial Transiton Mixed Agriculture Rangeµg/L µg/L µg/L µg/L µg/L
Pb 13 11 12 1.5 5Cu 14.5 11 13.9 1.5 10Zn 180 60 141 16 6Cd 0.96 1 1.05 1 1Cr 10 3 5.5 10 7.5Ni 11.8 4 7.3 N/A N/A
Using metal concentrations in stormwater runoff obtained by Baird and Jenning
(1996), estimates of total annual loading to the retention basin were calculated. These
annual rates were then compared to the calculated total mass of each metal existing in the
upper 10 cm of soil in cell 1 of the basin, to determine the expected time frame needed to
reach these specific levels (Table 7).
Table 7. L-THIA generated loading rates compared to estimated total mass in SEEP.
Estimated Age of SoilSurface (Yr)
(total mass/loading rate)
Cd 90.00 92.2 1.0Cr 20,628 303.2 68.0Cu 10,482.00 978.1 10.7Ni 2,916.00 353.6 8.2Pb 9,177 978.1 9.4Zn 30,096.00 5,364.6 5.6
MetalTotal Mass inUpper 10 cmof Soil (kg)
L-THIA GeneratedLoading Rates (kg/yr)
112
When evaluating the results from L-THIA compared to actual metal
concentrations, Cu, Ni and Pb, were the closest concentrations in years of loading to the
time frame of 11 years, which was the age of the basin when the sampling was
conducted. Rates for Cd, Cr, and Zn, were less accurate. Factors affecting the out come
of these results may come from not using site specific data, and the fact that the basin was
assumed to have the same land use categories for the entire 11 years, not reflecting any
development in the area. In spite of the difference in values obtained for the last three
metals, the L-THIA model may be a valuable tool in determining pollutant build-up over
time. Site specific data could play a major role in determining assessments for build-up,
which could lead to regulations for site remediation.
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RECOMMENDATIONS
From data collected, literature reviewed, and field observations, the following
recommendations are offered in regards to continued operation of the SEEP.
1. A study to determine contaminant bio-availability should be completed at several
sites within the SEEP. Metal concentrations above TELs and PELs as established in
the SQAGs were documented to exist at these locations. While SQAG values may
indicate the potential for adverse biological effects, they alone should not be used to
establish sediment removal criteria.
2. Sediments should be removed from the three locations where contaminant
concentrations were above residential toxicity values for the SCTLs, established in
Chapter 62-777, F.A.C. These levels are based on exposure through dermal contact,
ingestion or inhalation potential. While the potential may be low for human safety
factors, the risk to the wildlife communities in the area is unknown.
3. An assessment of the sediments for traffic related petroleum hydrocarbons and PAH’s
should be conducted.
4. Toxicity Characteristics Leaching Procedures (TCLP’s) should be performed in areas
where the Soil Contaminant Cleanup Target Levels have been exceeded. This can
assess the potential of the contaminants to spread throughout the basin, and will be
useful in directing the method of sediment disposal upon removal.
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5. A study at the SEEP should be completed on the effects metal contamination may
have on wildlife and vegetative communities. This study could directly impact the
future direction in which the SEEP develops.
6. Monitoring should be continued for contamination of sediments within the SEEP.
Now that concentrations for metals have been established, periodic checks, based on
resource availability, should be completed by UF. This will generate data regarding
the efficiency of the stormwater system on pollutant removal, and allow for
potentially toxic or hazardous areas to be identified and addressed accordingly.
7. The SEEP area should be posted with signs indicating the potential for exposure to
possible contaminants contained in stormwater, and that precautions should be taken
when working within the basin.
As focus on the disposal of urban stormwater runoff continues to shift from
quantity to quality based concerns, more research will be required to assess the
functionality of wetland systems being used as contaminant filters. While studies have
shown wetlands are capable of removing pollutants from stormwater runoff, higher
quality of discharge does not always equate to increased environmental protection. We
should not solely accept the benefits of ground and surface water protection through the
use of stormwater management systems, without recognizing the potential for localized
sediment contamination. Stormwater management system evaluations similar to the one
conducted on the SEEP have shown the potential for contamination in sediments to reach
levels above toxicity guidelines established for soil cleanup sites, as well as exceedences
of biological effects levels for aquatic organisms (FDEP, 2001).
115
State, regional, and local governmental codes have been established to regulate
stormwater runoff relating to issues of flood control, on-site sediment containment, and
quality of discharge to receiving waters. Regulation on sediment quality within
stormwater management systems is not adequately addressed. Differing techniques of
studies along with the variability of urban stormwater discharge between sites has made it
difficult to establish rules governing the pollutant potential of these sediments. Many
times, guidelines such as the SCTLs or the SQAG are indirectly applied to sediment
studies for assessment purposes only. In the past, environmental protection from
contaminated sediments was controlled through limiting access and decreasing
desirability of stormwater management systems. However, as wetland systems become a
more popular method of stormwater treatment and disposal, opportunities increase for the
direct exposure of contamination from sediments to a variety of ecological communities,
with the SEEP being no exception.
The University of Florida has created a unique opportunity of environmental
study with the development of the SEEP at the NATL. The design for this stormwater
management system, with its multiple wetland communities, creates conditions
conducive to attracting and sustaining a variety of wildlife species. In addition, the
University’s plan for using this site for continuing classroom study and research, along
with the ease of accessibility by the public, bridge the barriers protecting humans and
wildlife from exposure to possible contaminated sediments. By addressing current
contaminant areas, and monitoring for future concerns, the retention basin at the NATL
may continue to be a vital research area, without the possessing the potential to impact
human and environmental health.
APPENDIX AACRONYM LIST OF AGENCIES AND PROGRAM AREAS
117
Table A-1. Common acronyms used in this text.
FDEP Florida Department of Environmental Protection
Texas Natural Resource Conservation CommissionUnited States Environmental Protection Agency
DCA
EPAERP
FDOTNATLNOM
NPDES
Soil Quality Assessment GuidelineSuwannee River Water Management DistrictSouthwest Florida Water Management DistrictThreshold Effects Level
Soil Conservation ServiceSoil Clean-up Target LevelStormwater Ecological Enhancement ProgramSt. Johns River Water Management District
National Pollutant Discharge Elimination SystemNon-Point Source Management ProgramNationwide Urban Runoff ProgramProbable Effects Level
TNRCCUSEPA
Department of Community AffairsDepartment of Environmental RegulationEnvironmental Protection AgencyEnvironmental Resource Permit
Florida Department of TransportationNatural Area Teaching LabNatural Organic Matter
SQAGSRWMD
SWFWMDTEL
SCSSCTLSEEP
SJRWMD
NPSMPNURPPEL
DER
ATSDR
AcronymACEPD Alachua County Environmental Protection Department
Title
Agency for Toxic Substances and Disease Registry
APPENDIX BADDITIONAL FIGURES
119
Existing Pond
ProposedStormwaterBasin - 1988
#1
#2
#3
#4
#5
#6
#7
#8
#9
#10
#11
#12
#13
#14
Figure B-1. 1988 proposed retention basin with soil boring locations.
Figure B-2. Soil boring locations 1 – 4. Borings conducted in 1988 by Bishop Beville for the University of Florida.
120
Figure B-3. Soil boring locations 5 – 8. Borings conducted in 1988 by Bishop Beville for the University of Florida.
121
Figure B-4. Soil boring locations 9 – 12. Borings conducted in 1988 by Bishop Beville for the University of Florida.
122
Figure B-5. Soil boring location 13. Borings conducted in 1988 by Bishop Beville for the University of Florida.
123
APPENDIX CANALYTICAL RESULTS
125
Table C-1. Particle-size analysis for cell 1
Site Depth % Sand % Silt % Clay Textural ClassA1 0-5cm 89.24 7.40 3.36 SandA1 5-10cm 93.56 4.84 1.60 SandA2 0-5cm 96.24 2.64 1.12 SandA2 5-10cm 92.36 2.36 5.28 SandA3 0-5cm 82.30 4.58 13.12 Loamy SandA3 5-10cm 82.69 5.31 12.00 Loamy SandA4 0-5cm 96.58 1.98 1.44 SandA4 5-10cm LAB ERROR N/A N/AA5 0-5cm 89.74 4.82 5.44 SandA5 5-10cm 37.23 47.25 15.52 LoamA6 0-5cm 87.80 3.24 8.96 Loamy SandA6 5-10cm 95.28 2.48 2.24 SandA7 0-5cm 73.78 4.94 21.28 Sandy Clay LoamA7 5-10cm 74.54 4.34 21.12 Sandy Clay LoamA8 0-5cm 67.88 5.72 26.40 Sandy Clay LoamA8 5-10cm 65.16 4.60 30.24 Sandy Clay LoamA9 0-5cm 85.62 4.94 9.44 Loamy SandA9 5-10cm 83.49 5.79 10.72 Loamy SandA10 0-5cm 64.29 8.03 27.68 Sandy Clay LoamA10 5-10cm 64.56 5.20 30.24 Sandy Clay LoamA11 0-5cm 64.90 8.86 26.24 Sandy Clay LoamA11 5-10cm 65.28 7.68 27.04 Sandy Clay LoamA12 0-5cm 55.45 11.75 32.80 Sandy Clay LoamA12 5-10cm 62.16 3.76 34.08 Sandy Clay Loam
126
Table C-2. Particle-size analysis for cell 2
Site Depth % Sand % Silt % Clay Textural ClassB1 0-5cm 65.22 5.34 29.44 Sandy Clay LoamB1 5-10cm 70.76 3.96 25.28 Sandy Clay LoamB2 0-5cm 67.67 7.37 24.96 Sandy Clay LoamB2 5-10cm 67.57 4.43 28.00 Sandy Clay LoamB3 0-5cm 67.40 7.96 24.64 Sandy Clay LoamB3 5-10cm 69.07 6.29 24.64 Sandy Clay LoamB4 0-5cm 58.48 6.16 35.36 Sandy Clay LoamB4 5-10cm 61.96 7.64 30.40 Sandy Clay LoamB5 0-5cm 52.22 14.66 33.12 Sandy Clay LoamB5 5-10cm 71.49 9.95 18.56 Sandy Loam
Table C-3. Particle-size analysis for cell 3 and control site
Site Depth % Sand % Silt % Clay Textural ClassC1 0-5cm 39.72 15.64 44.64 ClayC1 5-10cm 41.45 13.43 45.12 Clay LoamC2 0-5cm 68.70 5.86 25.44 Sandy Clay LoamC2 5-10cm 84.76 8.04 7.20 Loamy SandD1 0-5cm 96.58 1.98 1.44 SandD1 5-10cm 89.22 6.62 4.16 Sand
127
Table C-4. Laboratory analysis for percent organic carbon (%OC), percent organicmatter (%OM), and pH.
Site Location Depth %OC %OM pH (H20) pH (KCl)A1 0-5cm 1.52 3.70 7.6 7.1
5-10cm 0.96 2.70 7.6 7.5
A2 0-5cm 7.00 13.62 7.9 7.8
5-10cm 7.00 10.00 8.1 7.7
A3 0-5cm 7.00 14.62 7.8 7.1
5-10cm 0.99 3.00 8.1 7.5
A4 0-5cm 2.33 2.70 8.3 7.8
5-10cm 1.11 1.70 8.3 7.9
A5 0-5cm 7.00 22.00 8.3 7.8
5-10cm 7.00 21.00 7.6 7.4
A6 0-5cm 4.11 7.00 6.2 4.7
5-10cm 0.36 5.00 5.9 4.7
A7 0-5cm 0.64 4.30 6.8 6.6
5-10cm 0.18 3.70 6.8 5.9
A8 0-5cm 2.10 4.00 6.5 5.4
5-10cm 0.11 5.00 5.8 4.2
A9 0-5cm 0.58 2.00 5.9 4.5
5-10cm 0.23 2.00 5.5 4.3
A10 0-5cm 3.48 6.70 7.2 6.6
5-10cm 0.14 5.30 5.5 4.3
A11 0-5cm 4.19 5.30 6.4 5.4
5-10cm 0.47 5.30 5.7 4.5
A12 0-5cm 0.85 2.00 5.9 4.5
5-10cm 0.37 1.00 6.2 4.9
B1 0-5cm 0.38 5.30 5.4 4.2
5-10cm 0.11 4.30 5.1 3.9
B2 0-5cm 0.27 4.00 7.1 5.8
5-10cm 0.21 4.70 7.0 5.7
B3 0-5cm 0.23 4.30 6.7 6.0
5-10cm 0.11 3.70 5.5 4.0
B4 0-5cm 0.23 5.00 5.8 4.7
5-10cm 0.11 5.00 5.6 4.4
B5 0-5cm 0.24 8.60 5.1 4.6
5-10cm 0.18 4.30 5.1 4.2
128
Table C-4. Continued
Site Location Depth %OC %OM pH (H20) pH (KCl)C1 0-5cm 1.72 11.00 7.0 5.8
5-10cm 0.54 7.00 6.8 5.6
C2 0-5cm 0.63 8.00 6.7 5.3
5-10cm 0.12 8.30 5.3 4.0
D1 0-5cm 0.78 3.60 6.1 5.5
5-10cm 0.75 2.60 6.2 5.6
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Table C-5. Metal Concentrations
Site Location Depth Cd Cr Zn Cu Ni Pb(mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg)
A1 0-5cm 0 45.5 41 16.5 5.5 75-10cm 0 20 22 13 4 3
A2 0-5cm 2.5 262.5 720 99.5 29 615-10cm 2.5 180 558 102 31.5 64.5
A3 0-5cm 1.5 250 444 148 19 42.55-10cm 0 40 39 9 11.5 18.5
A4 0-5cm 0 160 41.5 12.5 6 115-10cm 0 20.5 30.5 12 5.5 13.5
A5 0-5cm 1 177.5 276.5 61 15 24.55-10cm 0 139 94.5 18 6.5 32.5
A6 0-5cm 0 44.5 41 235 11.5 23.55-10cm 0 35.5 13 6 10.5 21.5
A7 0-5cm 0 21 17.5 15 8 145-10cm 0 23 9.5 4 7.5 14.5
A8 0-5cm 0 29 13 10.5 10 16.55-10cm 0 12 22 3.5 4 3.5
A9 0-5cm 0 27.5 18.5 45.5 7 8.55-10cm 0 13 12 3.5 4.5 2.5
A10 0-5cm 0 39.5 14 5.5 9.5 165-10cm 0 29.5 12.5 3 7.5 16.5
A11 0-5cm 0 38 36.5 22.5 10.5 195-10cm 0 32 14.5 4 9.5 18.5
A12 0-5cm 0 38 10.5 19 6 75-10cm 0 41.5 6.5 5 3.5 0.5
B1 0-5cm 0 25.5 15.5 11.5 8 17.55-10cm 0 24 9 5.5 7 13.5
B2 0-5cm 0 24.5 17 7.5 7 145-10cm 0 30 11 6 7.5 13.5
B3 0-5cm 0 27 16 5.5 7.5 145-10cm 0 27 12 4 7.5 12.5
B4 0-5cm 0 22.5 20.5 15 7.5 145-10cm 0 22.5 18 15 8 13
B5 0-5cm 0.5 44.5 57 15.5 11.5 26.55-10cm 0 21 28.5 9.5 5.5 11.5
C1 0-5cm 0 38.5 40 41 10 31.55-10cm 0 47.5 35 16 10 21.5
C2 0-5cm 0 32 35 16.5 8.5 265-10cm 0.5 38.5 20.5 6 8 18.5
D1 0-5cm 0 20.5 32.5 3 2.5 4.55-10cm 0 23.5 35.5 3 3 5
130
Table C-6. Metal concentrations compared to regulatory guidelines.
Metal (Cd)Site Concentration TEL PEL Residential Commercial
(mg/kg) (0.676 mg/kg) (4.21 mg/kg) (75 mg/kg) (1300 mg/kg)A2 0 - 5 cm 2.5 Yes No No NoA2 5 - 10 cm 2.5 Yes No No NoA3 0 - 5 cm 1.5 Yes No No NoA5 0 - 5 cm 1 Yes No No No
SQAGs SCTLs
Metal (Cr)Site Concentration TEL PEL Residential Commercial
(mg/kg) (52.3 mg/kg) (160 mg/kg) (210 mg/kg) (420 mg/kg)A2 0 - 5 cm 262.5 Yes Yes Yes NoA2 5 - 10 cm 180 Yes Yes No NoA3 0 - 5 cm 250 Yes Yes Yes NoA4 0 - 5 cm 160 Yes Yes No NoA5 0 - 5 cm 177.5 Yes Yes No NoA5 5 - 10 cm 139 Yes No No No
SQAGs SCTL
Metal (Cu)Site Concentration TEL PEL Residential Commercial
(mg/kg) (18.7 mg/kg) (108 mg/kg) (110 mg/kg) 76,000 mg/kg)A2 0 - 5 cm 99.5 Yes No No NoA2 5 - 10 cm 102 Yes No No NoA3 0 - 5 cm 148 Yes Yes Yes NoA5 0 - 5 cm 61 Yes No No NoA6 0 - 5 cm 235 Yes Yes Yes NoA9 0 - 5 cm 45.5 Yes No No NoA11 0 - 5 cm 22.5 Yes No No NoA12 0 - 5 cm 19 Yes No No NoC1 0 - 5 cm 41 Yes No No No
SQAGs SCTL
131
Table C-6 (cont.)
Metal (Zn)Site Concentration TEL PEL Residential Commercial
(mg/kg) (124 mg/kg) (271 mg/kg) (23,000 mg/kg) (560,000 mg/kg)A2 0 - 5 cm 720 Yes Yes No NoA2 5 - 10 cm 558 Yes Yes No NoA3 0 - 5 cm 444 Yes Yes No NoA5 0 - 5 cm 276.5 Yes Yes No No
SQAGs SCTLs
Metal (Pb)Site Concentration TEL PEL Residential Commercial
(mg/kg) (30.2 mg/kg) (112 mg/kg) (400 mg/kg) (920 mg/kg)A2 0 - 5 cm 61 Yes No No NoA2 5 - 10 cm 64.5 Yes No No NoA3 0 - 5 cm 42.5 Yes No No NoA5 5 - 10 cm 32.5 Yes No No NoC1 0 - 5 cm 31.5 Yes No No No
SQAGs SCTLs
Metal (Ni)Site Concentration TEL PEL Residential Commercial
(mg/kg) (15.9 mg/kg) (42.8 mg/kg) (110 mg/kg) (28,000 mg/kg)A2 0 - 5 cm 29 Yes No No NoA2 5 - 10 cm 31.5 Yes No No NoA3 0 - 5 cm 19 Yes No No No
SQAGs SCTLs
132
Table C-7. Regression analysis on all sites, n = 38.
All Samples - 0-10cm Outliers RemovedRegression r 2 p-value r 2 p-value
Cd vs. OM 0.2842 0.0006 0.4957 0Cr vs. OM 0.484 0 0.2671 0.0018Cu vs. OM 0.162 0.0123 0.2119 0.0062Ni vs. OM 0.2718 0.0008 0.5975 0Pb vs. OM 0.4441 0 0.7772 0Zn vs. OM 0.3377 0.0001 0.4426 0Cd vs. OC 0.5017 0 0.3208 0.0005Cr vs. OC 0.7373 0 0.5197 0Cu vs. OC 0.408 0 0.4716 0Ni vs. OC 0.5123 0 0.4371 0Pb vs. OC 0.5428 0 0.2838 0.0012Zn vs. OC 0.6089 0 0.5225 0Cd vs. % Clay 0.1674 0.0119 0.0222 0.4078Cr vs. % Clay 0.2197 0.0034 0.0678 0.1432Cu vs. % Clay 0.1164 0.0388 0.0493 0.2143Ni vs. % Clay 0.1006 0.0558 0.0011 0.8539Pb vs. % Clay 0.0509 0.1793 0.0228 0.4014Zn vs. % Clay 0.1755 0.0099 0.0231 0.3982
Cd vs. [H +] (in H 20) 0.0137 0.4834 0.0112 0.5521Cr vs. [H+] (in H 20) 0.0864 0.0733 0.0427 0.2411Cu vs. [H+] (in H 20) 0.0662 0.1189 0.0431 0.2385Ni vs. [H+] (in H 20) 0.0447 0.2028 0.0177 0.453Pb vs. [H+] (in H 20) 0.0368 0.2484 0.004 0.7216Zn vs. [H+] (in H 20) 0.0478 0.1872 0.0143 0.5008Cd vs. [H+] (in KCl) 0.0308 0.2917 0 0.9798Cr vs. [H+] (in KCl) 0.1097 0.0422 0.0602 0.1619Cu vs. [H+] (in KCl) 0.092 0.0641 0.0645 0.1472Ni vs. [H+] (in KCl) 0.0678 0.1144 0.0458 0.224Pb vs. [H+] (in KCl) 0.0728 0.1015 0.0316 0.3147Zn vs. [H+] (in KCl) 0.0689 0.1114 0.0365 0.279
133
Table C-8. Regression analysis on all sites 0 – 5 cm, n = 19
All Samples - 0-5cm Outliers RemovedRegression r 2 p-value r 2 p-value
Cd vs. OM 0.4943 0.0008 0.5414 0.0008Cr vs. OM 0.4569 0.0015 0.2675 0.0335Cu vs. OM 0.168 0.0814 0.2109 0.0636Ni vs. OM 0.508 0.0006 0.829 0Pb vs. OM 0.4968 0.0008 0.9409 0Zn vs. OM 0.4701 0.0012 0.5373 0.0008Cd vs. OC 0.5682 0.0002 0.3752 0.009Cr vs. OC 0.6858 0.5008 0.0015Cu vs. OC 0.3714 0.0056 0.4087 0.0057Ni vs. OC 0.6353 0 0.583 0.0004Pb vs. OC 0.4516 0.0016 0.3156 0.0189Zn vs. OC 0.618 0.0001 0.5189 0.0011Cd vs. % Clay 0.2031 0.0528 0.0175 0.6126Cr vs. % Clay 0.3752 0.0053 0.1967 0.0746Cu vs. % Clay 0.1795 0.0706 0.133 0.1501Ni vs. % Clay 0.1286 0.1316 0.0016 0.88Pb vs. % Clay 0.032 0.4637 0.0496 0.3903Zn vs. % Clay 0.2438 0.0317 0.0549 0.3656Cd vs. [H +] (in H 20) 0.0028 0.8295 0.023 0.5613Cr vs. [H+] (in H 20) 0.0538 0.3391 0.027 0.5285Cu vs. [H+] (in H 20) 0.0502 0.3566 0.0377 0.4554Ni vs. [H+] (in H 20) 0.0027 0.8325 0.0197 0.591Pb vs. [H+] (in H 20) 0 0.9832 0.0261 0.5359Zn vs. [H+] (in H 20) 0.0303 0.4762 0.0073 0.7444Cd vs. [H+] (in KCl) 0.0543 0.3372 0.0128 0.665Cr vs. [H+] (in KCl) 0.118 0.1499 0.0737 0.2919Cu vs. [H+] (in KCl) 0.0986 0.1906 0.0774 0.2795Ni vs. [H+] (in KCl) 0.0318 0.4653 0.0004 0.9386Pb vs. [H+] (in KCl) 0.0282 0.4919 0.0027 0.8424Zn vs. [H+] (in KCl) 0.0755 0.2549 0.0406 0.438
134
Table C-9. Regression analysis on all samples, 5 – 10 cm, n = 19
All Samples - 5-10cm Outliers RemovedRegression r 2 p-value r 2 p-value
Cd vs. OM 0.0805 0.2391 0.3206 0.0178Cr vs. OM 0.5583 0.0002 0.1163 0.1804Cu vs. OM 0.123 0.1409 0.0048 0.7906Ni vs. OM 0.4016 0.228 0.2599 0.0366Pb vs. OM 0.3741 0.0054 0.406 0.0059Zn vs. OM 0.143 0.1104 0.0178 0.6099Cd vs. OC 0.4249 0.0025 0.0366 0.4619Cr vs. OC 0.9156 0 0.0262 0.5348Cu vs. OC 0.573 0.0002 0.2552 0.0386Ni vs. OC 0.381 0.0049 0.0075 0.7408Pb vs. OC 0.6419 0 0.0017 0.8759Zn vs. OC 0.6055 0.0001 0.3807 0.0083Cd vs. % Clay 0.1328 0.1371 0.1017 0.2288Cr vs. % Clay 0.0729 0.2784 0.047 0.42Cu vs. % Clay 0.0914 0.2228 0.011 0.011Ni vs. % Clay 0.0833 0.2454 0 0.9857Pb vs. % Clay 0.0803 0.2545 0.0015 0.8884Zn vs. % Clay 0.1076 0.1839 0.001 0.9079
Cd vs. [H +] (in H 20) 0.0185 0.5785 0.0736 0.2923Cr vs. [H+] (in H 20) 0.1145 0.1564 0.1037 0.2076Cu vs. [H+] (in H 20) 0.0622 0.3032 0.0464 0.4064Ni vs. [H+] (in H 20) 0.072 0.2666 0.0684 0.3107Pb vs. [H+] (in H 20) 0.0797 0.2416 0.0164 0.6247Zn vs. [H+] (in H 20) 0.0532 0.3421 0.0239 0.5536Cd vs. [H+] (in KCl) 0.0171 0.5941 0.1512 0.123Cr vs. [H+] (in KCl) 0.1224 0.142 0.0692 0.3078Cu vs. [H+] (in KCl) 0.0885 0.2162 0.1574 0.1239Ni vs. [H+] (in KCl) 0.0618 0.3049 0.0274 0.5259Pb vs. [H+] (in KCl) 0.0768 0.2506 0.0049 0.7901Zn vs. [H+] (in KCl) 0.0697 0.2747 0.1287 0.1574
135
Table C-10. Regression analysis on cell 1, 0 – 5 cm, n = 12
All Samples - 0-5cm Cell 1 Outliers RemovedRegression r 2 p-value r 2 p-value
Cd vs. OM 0.5431 0.0063 0.7806 0.0007Cr vs. OM 0.5294 0.0073 0.4792 0.0265Cu vs. OM 0.1607 0.1965 0.35 0.0716Ni vs. OM 0.5194 0.0082 0.9056 0Pb vs. OM 0.4573 0.0158 0.9277 0Zn vs. OM 0.5165 0.0085 0.7912 0.0006Cd vs. OC 0.6381 0.0018 0.5551 0.0134Cr vs. OC 0.6486 0.0016 0.4643 0.03Cu vs. OC 0.2773 0.0786 0.3438 0.0748Ni vs. OC 0.706 0.0006 0.802 0.0005Pb vs. OC 0.6957 0.0007 0.8372 0.0002Zn vs. OC 0.6399 0.0018 0.5957 0.0089Cd vs. % Clay 0.1967 0.1487 0.0155 0.732Cr vs. % Clay 0.3277 0.0518 0.1545 0.2612Cu vs. % Clay 0.1329 0.2439 0.1087 0.3522Ni vs. % Clay 0.1176 0.2752 0.0046 0.8518Pb vs. % Clay 0.1221 0.2655 0.0005 0.9496Zn vs. % Clay 0.2209 0.1232 0.0379 0.59
Cd vs. [H +] (in H 20) 0.1549 0.2056 0.0815 0.4238Cr vs. [H+] (in H 20) 0.2627 0.0884 0.1824 0.2184Cu vs. [H+] (in H 20) 0.1349 0.2403 0.1176 0.332Ni vs. [H+] (in H 20) 0.0554 0.4615 0.0002 0.9722Pb vs. [H+] (in H 20) 0.0622 0.4345 0.0044 0.856Zn vs. [H+] (in H 20) 0.1626 0.1936 0.099 0.3758Cd vs. [H+] (in KCl) 0.1134 0.2845 0.0581 0.5025Cr vs. [H+] (in KCl) 0.1906 0.1559 0.1277 0.3107Cu vs. [H+] (in KCl) 0.1445 0.2229 0.1285 0.3092Ni vs. [H+] (in KCl) 0.0471 0.4981 0.0004 0.9554Pb vs. [H+] (in KCl) 0.0559 0.4592 0.0092 0.7923Zn vs. [H+] (in KCl) 0.1204 0.2692 0.0723 0.4525
APPENDIX DREGRESSION ANALYSIS
Figure D-1. Regression curve for Cr, Ni, Pb and Zn; all points are observed.
0.0
75.0
150.0
225.0
300.0
0.0 6.3 12.5 18.8 25.0
Cr vs X_OM
X_OM
Cr
-200.0
50.0
300.0
550.0
800.0
0.0 6.3 12.5 18.8 25.0
Zn vs X_OM
X_OM
Zn
0.0
8.8
17.5
26.3
35.0
0.0 6.3 12.5 18.8 25.0
Ni vs X_OM
X_OM
Ni
0.0
20.0
40.0
60.0
80.0
0.0 6.3 12.5 18.8 25.0
Pb vs X_OM
X_OM
Pb
rr22 == 00..4444
rr22 == 00..2277
rr22 == 00..3344
rr22 == 00..4488
AAllll DDaattaa PPooiinnttss
137
Figure D-2. Regression curve for Cr, Ni, Pb and Zn, with outliers removed
0.0
62.5
125.0
187.5
250.0
0.0 4.0 8.0 12.0 16.0
Cr vs X_OM
X_OM
Cr
-100.0
50.0
200.0
350.0
500.0
0.0 4.0 8.0 12.0 16.0
Zn vs X_OM
X_OM
Zn
0.0
5.0
10.0
15.0
20.0
0.0 4.0 8.0 12.0 16.0
Ni vs X_OM
X_OM
Ni
0.0
12.5
25.0
37.5
50.0
0.0 4.0 8.0 12.0 16.0
Pb vs X_OM
X_OM
Pb
rr22 == 00..7788
rr22 == 00..6600
rr22 00..4444
rr22 == 00..2266
OOuuttlliieerrss RReemmoovveedd
138
Figure D-3. Regression analysis for Pb and Ni in the top 5 cm of soil for every site throughout the entire basin.
5.0
15.0
25.0
35.0
45.0
2.0 5.5 9.0 12.5 16.0
Pb vs X_OM
X_OM
Pb
4.0
8.0
12.0
16.0
20.0
2.0 5.5 9.0 12.5 16.0
Ni vs X_OM
X_OM
Ni
rr22 == 00..9944 rr22 == 00..7766
EEnnttiirree BBaassiinn:: 00 -- 55 ccmm
139
Figure D-4. Regression analysis for Pb and Ni in top 5 cm of soil for sites located in cell 1.
5.0
15.0
25.0
35.0
45.0
2.0 5.5 9.0 12.5 16.0
Pb vs X_OM
X_OM
Pb
4.0
8.0
12.0
16.0
20.0
2.0 5.5 9.0 12.5 16.0
Ni vs X_OM
X_OM
Ni
rr22 == 00..9944 rr22 == 00..7766
EEnnttiirree BBaassiinn:: 00 -- 55 ccmm
140
141
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Beville, Bishop. 1988. Soil Boring Analysis at UF Basin #8. Bishop Beville & Associates, Inc, Gainesville, Florida.
Broadbent, F.E. “Organic Matter.” In C.A. Black (ed). Methods of Soil Analysis, Part 2. Agronomy 9. 1965. pp. 1397-1400. Am. Soc. Of Agron., Inc. Madison, Wisconsin.
Carleton, J.N., Grizzard, T.J., Godrej, A.N., & Post, H.E. “Factors Affecting The Performance of Stormwater Treatment Wetlands.” Journal of Water Resources, Vol. 35, No. 6. 2001. pp 1552-1562, 2001.
Carr, D.W. and Rushton, B.T. “Integrating A Native Herbaceous Wetland Into Stormwater Management.” 1995. Southwest Florida Water Management District, 2379 Broad St., Brookesville, Florida.
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Cheng, S.P., Grosse, W., Karrenbrock, F., and Thoennessen, M. “Efficiency of constructed wetlands in decontamination of water polluted by heavy metals.”Ecological Engineering, vol. 18. 2002. pp. 317-325.
Cox, J.H., Allick, S., and Be, E. “Characterization of Stormwater Contaminated Sediment and Debris for Determining Proper Disposal Methods.” 1998. Florida Department of Environmental Protection, Division of Water Facilities, 2600 Blairstone Road. Tallahassee, Florida.
Day, P.R. “Particle Fractionation and Particle Size Analysis.” In: C.A. Black (ed). Methods of Soil Analysis, Part I. Agronomy 9. 1965. pp. 545-567.
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145
BIOGRAPHICAL SKETCH
Mark Stanton Lander was born April 2, 1965, in Naples, Florida. He graduated
from Naples High School in 1983 and entered Edison Community College in Fort Myers,
Florida.
Upon completion of community college requirements, Mr. Lander entered the
University of Florida, College of Agriculture, and was awarded a bachelor’s degree in
food and resource economics in 1989. After graduation, he became employed by the
Florida Department of Health conducting studies in sewage disposal practices along the
Suwannee River, in North Florida. In 1994, Mr. Lander accepted a position with the
Alachua County Health Department as an Environmental Specialist and was later
promoted to water/waster supervisor.
In 1998, Mr. Lander re-entered the University of Florida to pursue a Master of
Science degree with specialization in urban soils. In September of 2003, he accepted a
position at the Columbia County Health Department, as Director of Environmental
Health. After graduation, Mr. Lander will continue his work in the environmental health
field.