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Final Report: Sediment Contamination Assessment Methods: Validation of Standardized and Novel Approaches
EPA Grant Number: R826200Title: Sediment Contamination Assessment Methods: Validation of Standardized and Novel Approaches
Investigators: Burton Jr., G. Allen , Clements, William , Krane, Daniel , Landrum, Peter , Stubblefield, William , Tiernan, Thomas
Institution: Wright State University - Main Campus , NOAA / GLERL
EPA Project Officer: Reese, David H.
Project Period: January 1, 1998 through December 31, 2000
Project Amount: $449,448
RFA: Contaminated Sediments (1997)
Research Category: Hazardous Waste/Remediation
Description:
Objective:The objective of this project were to: (1) determine whether freshwater sediment criteria and standard U.S. Environmental Protection Agency (EPA) acute and chronic toxicity and bioaccumulation tests are appropriate indicators of ecological risk, and (2) develop an effective approach to evaluate sediment contamination which includes: (a) an in situ component for sampling and testing to reduce uncertainty in determinations of risk, and (b) appropriate models for predicting sediment quality criteria. Summary/Accomplishments (Outputs/Outcomes):
The assessment of aquatic ecosystem quality usually entails collection of physicochemical data with comparisons to standards (or criteria, guidelines, values, and/or benchmarks). In more comprehensive studies, comparisons also are made to indigenous biota community structure. Sometimes, these studies also include laboratory toxicity testing and tissue residue and habitat analyses. On rare occasions, "biomarkers", in situ caged organisms, or mesocosms are used in the regulatory assessment process. This multi-phase study evaluated the validity of various approaches for assessing sediment contamination, while identifying controlling factors, strengths, and limitations of each. Actual exposures were defined and comparisons made between laboratory and in situ exposures. Physicochemical profiles were compared with biological responses and sediment quality guidelines (EPA and others). During the past 3 years, traditional assessment investigations (e.g., site chemistry, sediment quality guidelines, benthic indices, and laboratory toxicity testing) were conducted in conjunction with in situ-based methods (e.g., caged organisms, habitat, and pore water flow) at seven sites in the United States (Clark Fork River, MN; Sebasticook River, ME; Lower Housatonic River, MA; Des Plaines River, IL; and Little Scioto River, Dicks Creek, and Wolf Creek, OH). These sites were contaminated to varying degrees by industrial, municipal, and agricultural inputs, including: polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), other nonpolar organics, pesticides, metals, ammonia, and suspended solids. Examples are presented of the strengths and limitations of the various methods that have led us to development of an effective, tiered, weight-of-evidence (WOE) approach that reduces uncertainty in assessments. Biological responses/indicators ranged from DNA RAPD fingerprints and benthic community indices, tissue residues (indigenous and surrogates), and toxicity (survival and/or growth) of Hyalella azteca, Chironomus tentans, Lumbriculus variegatus, Ceriodaphnia dubia, Daphnia magna, Pimephales promelas, Hydra littoralis, Corbicula fluminea, Lophopodella carteri, and Hexagenia limbata. Tier 1 focused on in situ exposures of caged organisms. Results have shown acute toxicity existing at the test sites resulting from metals, PAHs, and PCBs. Spatial variation has ranged from small to large at the test sites. Toxicity has been greater in sediment exposures than in overlying waters. When adverse effects were found in specific compartments (e.g., low or high flow, surficial sediment, or pore waters) or were suspected from guideline exceedances, more in-depth assessments were conducted in Tier 2 that focused on identifying major stressor classes (e.g., nonpolar organics, metals, ammonia, and suspended solids). If necessary and resources allow, additional approach methods are selected in Tier 3 that build a WOE case of whether significant ecological effects exist and identify the stressor types. Sediment criteria, also called Sediment Quality Guidelines (SQGs), were found to be reliable at some sites and not at others, with greater reliability at the more heavily contaminated sites. At some sites the SQGs were overly protective, while at others they were under-protective. in situ methods have worked very well and provided more accurate measures of contamination than traditional laboratory assays with minimal physicochemical characterizations. This approach allows for site-specific study design with limited resources, yet, produces reliable, easily interpretable data on aquatic ecosystem quality. The approach should be particularly useful for TMDLs, ecological risk assessments, beneficial use attainment monitoring, storm water monitoring, and ambient monitoring programs.
Methods. The methods used in the seven studies conducted from 1998 to 2000 are described in detail in the following: Burton (1998, 1999, 2000a,b); Burton and Moore (1999); Burton and Rowland (1998, 1999, 2000); Burton, et al. (1998, 1999, 2000); Chappie and Burton (1997, 2000); Greenberg and Burton (1999, 2000); Greenberg, et al. (1998, 2000); Moore and Burton (1998); Nordstrom and Burton (2000a,b), Nordstrom, et al. (1999); Rowland and Burton (2000); Rowland, et al. (2000a,b); and Tucker and Burton (1999).
Seven streams were studied on several occasions in 1997 through 2000. They are listed with the dominant stressors that have been identified in these and other studies: Dicks Creek, near Middletown, OH (PCBs and PAHs); Little Scioto River, near Marion, OH (PAHs); Wolf Creek, near Dayton, OH (suspended solids, ammonia, nonpolar organics); Clark Fork River, near Butte, MN (metals); Lower Housatonic River, near Lenox, MA (PCBs); Sebasticook River, near Corinna, ME (chlorobenzenes); and the Des Plaines River, near Joliet, IL (temperature, ammonia, nonpolar organics). Only Dicks Creek, the Little Scioto River, and the Clark Fork were originally proposed as test sites, however, the opportunity for evaluating the project objectives at other sites (funded by other EPA, city, and industrial sponsors) strengthened the findings and are included here.
The study designs varied with each site and other supporting investigations were being conducted by other investigators. However, the basic study design was as follows. Stations were selected upstream and downstream of the zone of suspected contamination and at reference sites on nearby streams. Stations were selected that represented a gradient of contamination or were located near suspected source loadings. There were usually four to six stations selected, including reference sites.
in situ deployments were conducted at each site for periods of 1 to 10 days with multiple species in replicated treatments for toxicity and bioaccumulation testing. Physicochemical monitoring during exposures included: dissolved oxygen, temperature, conductivity, pH, turbidity, ammonia, hardness, alkalinity, and flow. Most of these parameters were monitored continuously with YSI datasondes, or at a minimum collected by grab sampling at test initiation and termination and during flow events. Flow information was collected from nearby U.S. Geological Survey gauging stations or using Marsh-McBirney flow meters. Groundwater upwelling and downwelling was measured using mini-piezometers (see below).
During in situ exposures, benthic macroinvertebrates were collected for identification to the lowest practical taxon (usually family or genus) and sediment and water samples collected for laboratory toxicity testing and physicochemical analyses (grain size, organic carbon, metals, and nonpolar organics). Chemical analyses varied with the site and study objectives. All physicochemical analyses, qualitative habitat evaluations, benthic invertebrate sampling, and laboratory toxicity testing followed standard EPA methods.
At most sites, repeated sampling and exposures were conducted with synoptic sampling in all cases. Data analyses included standard tests for statistical significance of treatment effects and correlations. A weight-of-evidence approach was used to determine dominant stressors and the ecological significance of the adverse effects by comparing the following assessment methods: water and sediment quality guidelines, physicochemical profiles, laboratory and in situ toxicity, and bioaccumulation, benthic community structure, habitat quality, and toxicity identification evaluations (laboratory and in situ).
For routine toxicity and bioaccumulation evaluations, the following chamber design was used. in situ chambers were constructed of clear core sampling tubes (cellulose acetate butyrate) cut to a length of approximately 15 cm. Polyethylene closures capped each end. Two rectangular windows covered with 80 micron Nitex? mesh on each core tube opposite each other. Exposures differ in water only exposures or sediment/water interface exposures by altering the design and placement of the exposure chambers. in situ chambers exposed to the overlying water column (WC chambers) were tethered inside wire baskets, which provided a specific compartmentalized exposure. Sediment-water interface chambers were positioned on bottom with mesh windows against the sediment.
For field TIE exposures, a modified chamber design was used that pumped pore water through resins (zeolite, chelex, ambersorb) that selected for particular chemical types (ammonia, metals, nonpolars) and then passed into an organism exposure chamber (Nordstrom and Burton, 2000a,b; Nordstrom, et al., 1999).
To detect areas of upwelling and downwelling, nested mini-piezometers were installed at the test sites following established methods (Lee and Cherry, 1978; Valett, et al., 1994; Fraser, et al., 1996; and Fraser and Williams, 1998).
The hydraulic conditions of the exposure areas were characterized by installing nests at in situ testing locations as close to the exposure chambers as possible. Hydraulic heads were determined with a manometer by measuring the heights of water columns drawn simultaneously from the inserted mini-piezometer and overlying surface water (Winter, et al., 1988). Relative to surface water, a positive or negative hydraulic head indicates an upwelling or downwelling zone, respectively.
In the laboratory, short-term assessments of organism mortality were conducted for 2 to 10 days following EPA methods (U.S. EPA, 2000). In addition, bioaccumulation was assessed in the laboratory using L. variegatus for 2 days to 4 weeks (U.S. EPA, 2000).
Results and Discussion. The seven studies conducted during the past 3 years showed a range of chronic to acute toxicity existed at the various sites. Toxicity was found to be associated with different environmental compartments (low flow, high flow, surficial sediments, and pore waters) depending on the station location and time of evaluation, documenting significant spatial and temporal variation at most sites.
The multi-exposure design of the in situ chambers allowed for separation of effects into water, sediment interface (labeled "against sediment"), surficial sediment, and pore water toxicity and bioaccumulation. Toxicity often was noted to differ between laboratory whole sediment exposures and the results of the in situ exposures (Burton, et al., 1999 and 2000). At Dicks Creek, sediment toxicity was reduced in laboratory exposures. This also was noted in the Lower Housatonic exposures (Burton, et al., 1999), but the opposite was observed in the Little Scioto River where PAHs dominated (Sasson-Brickson and Burton, 1991). These differences should not be surprising, as the exposures of the test organisms in the laboratory differ from that in the field, and the sampling and manipulation of sediments in the laboratory can alter the availability of contaminants. These data revealed sources of stressors, such as: historical contamination (bedded sediment exposures), continuous point source inputs (low flow exposures), groundwater upwelling/downwelling (pore water exposures with flow data), or nonpoint source runoff (high flow exposures).
Bioaccumulation testing also was performed at most sites using L.variegatus, H. azteca, and/or C. tentans. PCB concentrations in L. variegatus were determined for exposures in the Lower Housatonic River. The isomer patterns observed in the tissues were similar to those observed in surficial sediments. The organisms quickly accumulated PCBs within the first 48 hours of exposure. Mortality was observed at concentrations below the critical body residue levels reported in the literature, which may indicate stressor interactions, or mechanisms other than narcosis are affecting the organisms. These data provided verification for food web models used in ecological risk assessments by documenting organism uptake rates, contaminant source, and availability.
At sites where PAHs are present, it is essential to consider the toxic interactions of ultraviolet light producing what is referred to as "photo-induced" toxicity. The Little Scioto River is heavily contaminated with PAHs and subject to photoinduced toxicity (Sasson-Brickson and Burton, 1991; Ireland, et al., 1996). The effects of organisms exposed in shaded or unshaded chambers in situ. In all cases during low flow conditions, chambers exposed to direct sunlight showed increased mortality of test organisms. However, at high flow conditions, toxicity was reduced, likely due to high turbidity, which blocked the light and PAH binding (Ireland, et al., 1996).
Groundwater upwelling and downwelling are important issues at many sites (U.S. EPA, 2000). The transition zone between surface and groundwaters (also known as the hyporheic zone) is important from an ecological perspective, often containing a rich diversity of micro-, meio-, and macrofauna where organic matter and nutrient cycling processes dominate. If either ground- or surface waters are contaminated, they may contaminate the other, and of course impact resident aquatic communities. In addition, if porewaters are transient, then the equilibrium partitioning assumptions of EPA's sediment quality guidelines are invalid. Indeed, at the Sebasticook River, the high concentrations of sediment chlorobenzenes (21 µg/kg) occurred at Station 23 where virtually no toxicity was observed due to surface water downwelling. At upstream stations where chlorobenzene contamination in sediments was lower, higher toxicity was observed because porewaters were either static or upwelling from the source of contamination. The mini-piezometers placed around the in situ chambers provided essential information that allowed exposures to be accurately assessed and chemistry to be correctly interpreted (Burton, et al., 2000). Laboratory whole sediment toxicity testing showed no toxicity, likely due to the volatile nature of chlorobenzenes, which were rapidly lost during the initial phase of the assays.
A comprehensive assessment of Wolf Creek showed no toxicity during low flow, except from depositional sediments at one site where ammonia was highly elevated. Storm water exposures revealed toxicity. To ascertain the effects of suspended solids (elevated turbidity occurred during high flows), in situ chambers were fitted with varying sizes of mesh with both single and double layers. The effects of solids are apparent, with increasing mortality associated with larger mesh sizes. D. magna and P. promelas larvae were more sensitive to solids than the two benthic invertebrates. It appears in Wolf Creek that solids (and perhaps contaminants associated with solids) are the primary stressor (Burton and Moore, 1999).
After confirming the presence of toxicity in sediments and pore waters, an in situ toxicity identification evaluation (TIE) was conducted at Dicks Creek. D. magna were exposed to flowing pore water for 24 hours in various treatments. The results showed acute toxicity in the pore-water-only exposure. The greatest survival occurred in the Ambersorb resin treatment, which selects for nonpolar organics. These results confirm that the primary stressors in Dicks Creek are nonpolar organics (PCBs dominate). Draft EPA methods for laboratory TIE testing of sediments involves centrifugation of sediments with subsequent testing of pore waters. After these manipulations, no toxicity was observed, which is disconcerting because the in situ exposures showed that acute toxicity exists in pore waters.
It has become apparent from the experiences at these seven sites and previous investigations, that a tiered, weight-of-evidence approach that focuses on in situ assessments is superior to traditional approaches. The SQGs correctly predicted toxicity at some sites but not at others. The likelihood of false positives and false negatives associated with SQGs, suggests that they may only be used in a screening approach and when integrated with other assessment methods. In the initial phase, a site and historical survey should determine whether bioaccumulative compounds may exist, whether PAHs exist, and whether groundwater-surface water transition zones exist. If any of these three may occur, then the study design should include: tissue residue analyses, phototoxicity testing (UV versus dark exposures), and/or mini-piezometer monitoring, respectively. The tiered design and the triggers that dictate moving to a higher tier are flexible and largely driven by project specific issues. However, the approach described places less emphasis on initial collection of expensive chemical analyses (e.g., metals and organics) until Tier 2 or even Tier 3, when confirmation and stressor identification are required. The initial focus is on rapid determination of whether adverse biological effects are occurring, and if so, from which compartment they are originating. This approach is more efficient and less subject to sampling/testing artifacts, laboratory extrapolations, and other assumptions that contribute to uncertainty. Although the in situ based approaches have their own set of limitations, they provide unique data that cannot be obtained through traditional approaches. Only by combining multiple assessment tools can uncertainty be reduced to acceptable levels in most sites where chronic toxicity is of concern.
Acknowledgment. Although the research described in this report has been funded largely by EPA's STAR Program, it has not been subjected to any EPA review and, therefore, does not necessarily reflect the views of the Agency, and no official endorsement should be inferred.
References:
Burton Jr GA. The upper Illinois waterway ecological survey: continuous in situ toxicity monitoring and thermal effect characterization tasks. Commonwealth Edison Corporation, Chicago, IL, 1998.
Burton Jr GA. Realistic assessments of ecotoxicity using traditional and novel approaches. Journal of Aquatic Ecosystem Health and Management 1999;2:1-8.
Burton Jr GA, Moore L. An assessment of storm water runoff effects in Wolf Creek, Dayton, OH. Final Report, City of Dayton, OH, 1999.
Burton Jr GA, Rowland C. Assessment of sediment toxicity in the Black River Watershed. Final Report. U.S. Environmental Protection Agency, Great Lakes National Program Office, Chicago, IL, 1998.
Burton Jr GA, Rowland C. Assessment of in situ stressors and sediment toxicity in the Lower Housatonic River. Final Report to Weston RF, Manchester, NH, 1999.
Burton Jr GA, Rowland C. Assessment of in situ toxicity at the Eastern Woolen Mill Superfund Site. Final Report to Harding Lawson Associates, Portland, ME, 2000.
Burton Jr GA, Greenberg MS, Rowland C. Ecological risk assessment of Dicks Creek, Middletown, OH. Final Report, Tetra Tech EM, Inc., Chicago, IL, 2000.
Burton Jr GA, Lavoie DR, Greenberg, MS, Hall TA, Irvine CA, Johnson J, Nordstrom JF, Rowland CD. Linking multiple assessment tools in a weight of evidence approach for identifying stream stressors. Abstract from the Annual Meeting of the Society of Environmental Toxicology and Chemistry, Nashville, TN, 2000.
Burton Jr GA, Rowland C, Greenberg M, Lavoie D, Brooker J. Determining the effect of ammonia at complex sites: laboratory and in situ approaches. Abstract from the Annual Meeting of the Society of Environmental Toxicology and Chemistry, Charlotte, NC, 1998.
Burton Jr GA, Nordstrom JF, Rowland CD, Greenberg MS, Lavoie DR, Fox L. Teasing out primary stressors in aquatic systems using various exposure chambers. Abstract from the Annual Meeting of the Society of Environmental Toxicology and Chemistry, Philadelphia, PA, 1999.
Burton Jr GA. The role of in situ toxicity testing in sediment assessments. Abstract from the Annual Meeting of the Society of Environmental Toxicology and Chemistry, Nashville, TN, 2000.
Burton Jr GA. Sediment contamination methods: validation of standardized and novel approaches. Abstract from the Annual Meeting of the Society of Environmental Toxicology and Chemistry, Nashville, TN, 2000.
Chappie D J, Burton Jr GA. Optimization of in situ bioassays with Hyalella azteca and Chironomus tentans. Environmental Toxicology and Chemistry 1997;16:559-564.
Chappie DJ, Burton Jr GA. Applications of aquatic and sediment toxicity testing in situ. Journal of Soil and Sediment Contamination 2000;9:219-246.
Fraser BG, Williams DD, Howard KWF. Monitoring biotic and abiotic processes across the hyorheic/groundwater interface. Hydrogeology Journal 1996;4:36-50.
Fraser BG, Williams DD. Seasonal boundary dynamics of a groundwater/surface water ecotone. Ecology 1998;79:2019-2031.
Greenberg MS, Burton Jr GA, Lavoie DR, Gallagher JS, Huckins JN. Use of transect sampling with mini-piezometers for the characterization of groundwater-surface water interactions and ecological effects during in situ sediment toxicity testing. Abstract from the Annual Meeting of the Society of Environmental Toxicology and Chemistry, Nashville, TN, 2000.
Greenberg M, Rowland C, Burton GA, Hickey C, Stubblefield W, Clements W, Landrum P. Isolating individual stressor effects at sites with contaminated sediments and waters. Abstract from the Annual Meeting of the Society of Environmental Toxicology and Chemistry, Charlotte, NC, 1998.
Greenberg MS, Burton Jr GA. Evaluation of the role of groundwater-surface water interactions in the toxicity of contaminated sediments. Abstract from the Annual Meeting of the North American Benthological Society, Keystone, CO, 2000.
Greenberg MS, Burton Jr GA. Evaluation of the role of groundwater upwelling in the toxicity of contaminated sediments. Abstract from the Annual Meeting of the Society of Environmental Toxicology and Chemistry, Philadelphia, PA, 1999 No. 552.
Greenberg MS, Burton Jr GA. Evaluation of the role of groundwater upwelling in the toxicity of contaminated sediments. In: Proceedings from the Annual Meeting of the Society of Environmental Toxicology and Chemistry, Philadelphia, PA, 1999, No. 552 (abstract).
Ireland DS, Burton Jr GA, Hess GG. in situ toxicity evaluations of turbidity and photoinduction of polycyclic aromatic hydrocarbons. Environmental Toxicology and Chemistry 1996;15:574-581.
Lee DR, Cherry JA. A field exercise on groundwater flow using seepage meters and mini-piezometers. Journal of Geological Education 1978;27:6-10.
Moore LA, Burton Jr GA. An ecotoxicological assessment of urban stormwater runoff using laboratory and in situ toxicity testing. Abstract from the Annual Meeting of the Society of Environmental Toxicology and Chemistry, Charlotte, NC, 1998.
Nordstrom JF, Burton Jr GA, Greenberg MS, Moore LA, Rowland CD. A novel stressor identification method for pore water and sediment. Abstract from the Annual Meeting of the Society of Environmental Toxicology and Chemistry, Philadelphia, PA, 1999 No. PWA197.
Nordstrom JF, Burton Jr GA, Greenberg MS, Moore LA, Rowland CD. A novel stressor identification method for pore water and sediment. In: Abstracts from the Annual Meeting of the Society of Environmental Toxicology and Chemistry, Philadelphia, PA, 1999, No. PWA197 (abstract).
Nordstrom JF, Burton Jr GA. in situ vs. laboratory toxicity identification evaluations. Abstract from the Third World Congress, Society of Environmental Toxicology and Chemistry?Europe, Brighton, England, 2000.
Nordstrom JF, Burton GA. in situ toxicity identification evaluation (TIE) method. Abstract from the Annual Meeting of the Society of Environmental Toxicology and Chemistry, Nashville, TN, 2000.
Rowland C, Burton GA. in situ bioaccumulation of sediment associated PAHs and PCBs in the freshwater oligochaete Lumbriculus variegatus and amphipod Hyalella azteca. Abstract from the Annual Meeting of the Society of Environmental Toxicology and Chemistry, Nashville, TN, 2000.
Rowland CD, Burton Jr GA, Greenberg MS, Lavoie DR, Nortstrom N, Moore L. Optimizing in situ confined chamber exposures for identifying stressors and their sources. Abstract from the Third World Congress, Society of Environmental Toxicology and Chemistry?Europe, Brighton, England, 2000.
Rowland CD, Greenberg MS, Lavoie DR, Brooker JA, Moore LM, Burton GA. Current methods for the in situ evaluation of multiple stressors in the aquatic environment. Abstract from the Annual Risk Assessment and Environmental Toxicology Conference, American Society of Testing and Materials, Toronto, Ontario, April 2000.
Sasson-Brickson G, Burton Jr GA. in situ and laboratory toxicity testing with Ceriodaphnia dubia. Environmental Toxicology and Chemistry 1991;10: 201-207.
Tucker KA, Burton Jr GA. Assessment of nonpoint source runoff in a stream using in situ and laboratory approaches. Environmental Toxicology and Chemistry 1999;18:2797-2803.
U.S. Environmental Protection Agency. Methods for measuring the toxicity and bioaccumulation of sediment-associated contaminants with freshwater invertebrates. 2nd edition, EPA/600/R-99/064. Office of Research and Development and Office of Water, Washington, DC, 2000.
Valett HM, Fisher SG, Grimm NB, Camill P. Vertical hydrologic exchange and ecological stability of a desert stream ecosystem. Ecology 1994;785:548-560.
Winter TC, LeBaugh JW, Rosenberry DO. The design and use of a hydraulic potentio-manometer for direct measurement of differences in hydraulic head between groundwater and surface water. Limnology and Oceanography 1998;33:1209-1214.
Journal Articles on this Report: 6 Displayed | Download in RIS Format
| Other project views: | All 63 publications | 9 publications in selected types | All 6 journal articles |
| Type | Citation | ||
|---|---|---|---|
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Burton Jr GA. Realistic assessments of ecotoxicity using traditional and novel approaches. Aquatic Ecosystem Health and Management 1999;2(1):1-8. |
R826200 (Final) R823873 (Final) |
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Burton GA, Pitt R, Clark S. The role of traditional and novel toxicity test methods in assessing stormwater and sediment contamination. Critical Reviews in Environmental Science and Technology 2000;30(4):413-447. |
R826200 (Final) |
not available |
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Chappie DJ, Burton GA. Applications of aquatic and sediment toxicity testing in situ. Soil and Sediment Contamination 2000;9(3):219-246. |
R826200 (Final) |
not available |
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Hatch AC, Burton Jr GA. Sediment toxicity and stormwater runoff in a contaminated receiving system: consideration of different bioassays in the laboratory and field. Chemosphere 1999;39(6):1001-1017. |
R826200 (Final) R823873 (Final) |
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Krane DE, Sternburg DC, Burton GA. Randomly amplified polymorphic DNA profile-based measures of genetic diversity in crayfish correlated with environmental impacts. Environmental Toxicology and Chemistry 1999;18(3):504-508. |
R826200 (Final) R826599 (Final) |
not available |
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Tucker KA, Burton GA. Assessment of nonpoint source runoff in a stream using in situ and laboratory approaches. Environmental Toxicology and Chemistry 1999;18(12):2797-2803. |
R826200 (Final) |
not available |
ecological risk assessment, exposure, indicators, ecosystem, measurement methods, TMDLs, stormwater monitoring, beneficial use attainment, sediments, bioavailability, toxics, metals, organics, in situ, sediment quality criteria, stressors, bioassay. , Ecosystem Protection/Environmental Exposure & Risk, Toxics, Water, Scientific Discipline, Waste, RFA, Ecosystem/Assessment/Indicators, Toxicology, Biology, HAPS, Ecology, Ecological Risk Assessment, Ecological Indicators, Biochemistry, Ecological Effects - Environmental Exposure & Risk, Ecosystem Protection, Contaminated Sediments, Ecology and Ecosystems, heavy metal contamination, risk assessment, spatial & temporal scaling, genetic diversity, predictive understanding, sediment contamination assessment, adverse human health affects, amphipod hyalella azteca, aquatic biota, bioaccumulation, ecology assessment models, validation, metal release, contaminated sediment, contaminant transport, ecological transferability, validation of models, ecological exposure, benthic biota, benthos-associated organisms, biota diversity, metals, polychlorinated biphenyls (PCBs), sediment transport, PAH, PCB, assessment methods, chemical contaminants, ecological impacts, sediment, soil sediment, transport contaminants
Relevant Websites:
http://www.wright.edu/~allen.burton/ 
Progress and Final Reports:
1999 Progress Report
Original Abstract