Grantee Research Project Results
2002 Progress Report: Center for the Study of Metals in the Environment
EPA Grant Number: R829500Center: Center for the Study of Metals in the Environment
Center Director: Allen, Herbert E.
Title: Center for the Study of Metals in the Environment
Investigators: Allen, Herbert E.
Institution: University of Delaware
EPA Project Officer: Hahn, Intaek
Project Period: April 1, 2002 through March 31, 2005
Project Period Covered by this Report: April 1, 2002 through March 31,2003
RFA: Targeted Research Center (2006) Recipients Lists
Research Category: Hazardous Waste/Remediation , Targeted Research
Objective:
The Center for the Study of Metals in the Environment is a multi-institutional consortium of scientists and engineers working to further the understanding of processes affecting the fate and effects of metals in aquatic and terrestrial ecosystems. Significant gaps in the ability to predict the fate and effects of metals in both aquatic and terrestrial systems continue to hamper appropriate risk assessments and cost-effective risk management. In these situations, decisions include many assumptions and the application of safety factors. The objective of this research project is to develop appropriate information so that regulatory decisions will be based on sound scientific principles. Much of the existing methodology for hazard identification and for risk assessment is based on experience with persistent organic pollutants such as dichloro-diphenyl-trichloroethane (DDT) and polychlorinated biphenyls (PCBs). The large differences in environmental behavior and potential for toxicity between organic compounds and metals are not incorporated into these methods. Assessment methodology currently is focused on the extent to which chemicals exhibit persistent, bioaccumulative, and toxic (PBT) characteristics. All three characteristics are important aspects of the assessment of risk, but their applicability to metals and the evaluation of metals data for these criteria differ from organic compounds.
As a replacement for the current methods for evaluating the effect of metals in the environment, the Center is developing a model for the behavior of metal compounds that can be used as a tool in the hazard assessment of metals and metal compounds. This model will include the physical and chemical mechanisms that control the fate and resulting bioavailability of metals discharged to natural waters. In particular, the transformations that affect metal fate and toxicity will be included. It is anticipated that it would be similar to the Unit World models; for example, the European Union System for the Evaluation of Substances (EUSES), which are used for evaluating PBT organic chemicals. Metal behavior in watersheds, streams, lakes, and reservoirs will be considered. The focus of this research effort is to provide the information necessary to formulate and parameterize the model.
Progress Summary:
Unit World Model (UWM) for Metals in Aquatic Environments
There is a clear need for methods that can be used for evaluating the environmental hazards associated with the release of metals and metal compounds to the environment (Adams, et al., 2000). The purpose of the UWM is to provide such a framework. The idea for a UWM comes from the fugacity and regional models developed for organic chemicals (Mackay, 1979, 1991; Mackay, et al., 1992). Models of this sort previously have been applied in various forms to pesticides (U.S. Environmental Protection Agency [EPA], 1986) and industrial organic chemicals (European Commission, 1996). The UWM for metals is structured such that it can be used to estimate both the exposure and effects of metal and metal compounds. It will incorporate the necessary metal specific processes that differentiate the behavior of metals from organic chemicals.
The UWM is designed to represent the major processes that determine the fate and transport of metals in the aquatic environment. In the water column, these processes include solubilization for particulate metal compounds, speciation among inorganic and organic dissolved ligands, and partitioning to suspended particles. The Windermere Humic Aqueous Model (WHAM) series of aqueous speciation models (Tipping, 1994) have been extensively calibrated and are well suited for incorporation in the UWM. A metal particle sorption model Steubenville Comprehensive Air Monitoring Program (SCAMP) also has recently become available (Lofts and Tipping, 1998). Although not as well calibrated, it provides a useful starting point.
The sorption of metals to water column particulate matter leads to the transfer of the metal to the bottom sediments. Sediments are the ultimate repositories of metals in aquatic settings. Several sediment models have been developed that successfully predict levels of sulfide (Acid Volatile Sulfide [AVS]) and partitioned simultaneously extracted metal (SEM) in sediments and resulting fluxes of dissolved metal from the sediments to the overlying water column (Di Toro, 1996; Carbanaro, 1999; Di Toro, 2001). Therefore, the frameworks exist for at least most of the processes in various stages of development, for the water column and sediment compartments.
Effects Concentration and Bioavailability
In addition to the exposure concentrations in the water column and sediment, it is necessary to predict the effects to be expected. The traditional method is to use an effects concentration for the water column and the sediment. For the water column, the U.S. EPA Water Quality Criteria (Stephen, et al., 1985, U.S. EPA 1986, 1996) or the Predicted No Effect Concentration (PNEC) derived following the European Union (EU) Technical Guidelines (EU, 1996) are possibilities. However, these criteria make only limited bioavailability corrections (for water hardness only). This is a much more critical issue for metals than for organic chemicals. To remedy this situation, the Biotic Ligand Model (BLM) recently has been developed (U.S. EPA, 1999, 2000; Di Toro, et al., 2000; Paquin, et al., 2002). It incorporates the WHAM speciation model, and in addition, models the competitive metal binding at the toxic site of action (the Biotic Ligand). BLMs currently are available for copper and silver (Di Toro, et al., 2000; Santore, et al., 2000), and zinc (Santore, et al., 2002), and are under development for cadmium, nickel, and lead.
The situation in the sediment is similar. There are guideline values that do not consider bioavailability—the sediment PNEC—or that are empirical and therefore are not predictive of individual metal toxicity (e.g., Long and Morgan, 1991; Field, et al., 2002).
For metals, the U.S. EPA has developed sediment quality guidelines that are causally related to metal effects and do take into account bioavailability. They are based on the relative magnitudes of AVS and SEM, and organic carbon (Di Toro, et al., 1990, 1992; Ankley, et al., 1993, 1996; U.S. EPA, 2000).
UWM Design and Testing
The design of the UWM is based on the processes required for calculating both the exposure concentration and the variables required for making the bioavailability corrections for the effects concentration. Because the model is expected to be used for site-specific evaluations as well as in regulatory settings, it needs to be predictive to the extent possible. This forces a more complex model structure than would be necessary for a strictly evaluative model with fixed physical, chemical, and biological variables. The current plan is to build the UWM using a water column/sediment eutrophication model as a basis (Di Toro, 2001). Modern eutrophication models compute most of the auxiliary variables required for metal modeling—carbon and sulfur cycles—and water column/sediment models for manganese and iron also are available, which are required for metal partitioning.
The steps in producing the model are to: (1) synthesize the available components into a unified modeling framework; and (2) test the model with laboratory and field data for a variety of metals. The testing will begin with experiments in which a suite of metals was added to freshwater (Diamond, 1990) and marine (Santschi, 1987) mesocosms, and long-term dosing experiments to a Canadian lake (Hesslein, 1980). There is one data set (O’Connor, 1988) that can be used for calibrating the model to freshwater streams. However, it is somewhat limited, and it was not collected using modern clean techniques. It is anticipated that most of the data for streams will need to be generated.
In February 2003, the Center held an international workshop—the Unit World Model Workshop—at the University of Delaware. Attendees included University researchers, EPA scientists and program managers, representatives from the metal industry, and many of the Center’s scientists. Both technical and regulatory issues were addressed.
Following the recommendation of the Center’s Science Advisory Committee (SAC), the Center Director and Associate Director convened two meetings with the investigators conducting filed work. A conference call was held in January 2003, followed by a workshop on field sampling and laboratory and analytical issues. The workshop was held immediately preceding the UWM Workshop.
Seven projects were completed in the first year of the grant. Many of these projects were designed to provide data for use in the initial development of the model. Separate reports were prepared on the progress of each of these projects.
Future Activities:
The research program will be expanded in Year 2. The SAC reviewed a series of proposals for research projects. Nine projects were approved for funding. Planning has been carried out with the SAC to allow the development of the UWM to be completed in a 3-year program. The following are the projects that were approved for Year 2:
| Investigator | Institution | Project Title |
|---|---|---|
| Adams, C.D | University of Missouri, Rolla | Metals Speciation and Transport in the Black River of Missouri’s New Lead Belt |
| Allen, H.E. | University of Delaware | Release of Metals from Particulate Matter |
| Capitani, J.F | Manhattan College | Quantitative Structure Activity Relationships for Toxicity and Fate Parameters of Metal and Metal Compounds |
| Church, T.M | University of Delaware | Metal Speciation in Watersheds |
| Di Toro, D.M | University of Delaware | Developing a Unit World Model for Metals in Aquatic Environments |
| Imhoff, P.T | University of Delaware | Evaluation of Automobile Sources for Metals in Urban Areas |
| Meyer, J.S | University of Wyoming | A Test of the Biotic Ligand Model: Fish Exposed to Time-Variable Concentrations of Cu and Zn |
| Ross, P. | Colorado School of Mines | Ecotoxicology of Mining-Related Metal Oxides in a High-Gradient Mountain Stream |
| Sparks, D.L. | University of Delaware | The Impact of Surface Precipitation on Sequestration and Bioavailability of Metals in Soils |
References:
Adams WJ, Conard B, Ethier G, Brix KV, Paquin PR, Di Toro DM. The challenges of hazard identification and classification of insoluble metals and metal substances for the aquatic environment. Human and Ecological Risk Assessment 2000;6(6):1019-1038.
Ankley GT, Mattson V, Leonard E, West C, Bennett J. Predicting the acute toxicity of copper in freshwater sediments: evaluation of the role of acid volatile sulfide. Environmental Toxicology and Chemistry 1993;12:312-320.
Ankley GT, Di Toro DM, Hansen DJ, Berry WJ. Technical basis and proposal for deriving sediment quality criteria for metals. Environmental Toxicology and Chemistry 1996;15(12):2056-2066.
Carbanaro R. Modeling metal sulfide fluxes from sediments. M.S. Thesis. Department of Environmental Engineering, Manhattan College, Riverdale, NY, 1999.
Diamond ML, Mackay D, Cornett RJ, Chant LA. A model of the exchange of inorganic chemicals between water and sediments. Environmental Science and Technology 1990;24(5):713-722.
Di Toro DM, Mahony JD, Hansen DJ, Scott KJ, Hicks MB, Mayr SM, Redmond MS. Toxicity of cadmium in sediments: the role of acid volatile sulfide. Environmental Toxicology and Chemistry 1990;9:1487-1502.
Di Toro DM, Hallden JA, Plafkin JL. Modeling ceriodaphnia toxicity in the Naugatuck River. II. Copper, hardness and effluent interactions. Environmental Toxicology and Chemistry 1991;10:261-274.
Di Toro DM, Mahony JD, Hansen DJ, Scott KJ, Carlson AR, Ankley GT. Acid volatile sulfide predicts the acute toxicity of cadmium and nickel in sediments. Environmental Toxicology and Chemistry 1992;26:96-101.
Di Toro DM, Mahony JD, Hansen DJ, Berry WJ. A model of the oxidation of iron and cadmium sulfide in sediments. Environmental Toxicology and Chemistry 1996;15(12):2168-2186.
Di Toro DM, Allen HE, Bergman HL, Meyer JS, Paquin PR, Santore RC. Biotic ligand model of the acute toxicity of metals. I. Technical basis. Environmental Toxicology and Chemistry 2001;20(10):2383-2396.
Di Toro DM. Sediment Flux Modeling. New York, NY: J. Wiley and Sons, Inc., 2001, 624 pp.
European Commission. EUSES documentation–the European union system for the evaluation of substances. Presented at the National Institute of Public Health and the Environment (RIVM), European Commission, Bilthoven, The Netherlands, 1996.
European Union. European union technical guidance document in support of commission directive 93/67/EEC on risk assessment for new notified substances and commission regulation (European Community No 1488/94) on risk assessment of existing substances. Part II. Brussels, Belgium, European Union, 1996, ISBN 92-827-8012-0.
Lofts S, Tipping E. An assemblage model for cation binding by natural particulate matter. Geochimica et Cosmochimica Acta 1998;62(15):2609-2625.
Long ER, Morgan LG. The potential for biological effects of sediment-sorbed contaminants tested in the national status and trends program, Seattle, WA, 1991. National Oceanic and Atmospheric Administration Technical Memorandum, NOS OMA 52.
Mackay D. Finding fugacity feasible. Environmental Science and Technology 1979;13:1218-1223.
Mackay D. Multimedia Environmental Models. Chelsea, MI: Lewis Publishers, 1991.
Mackay D, Paterson S, Shiu WY. Generic models for evaluating the regional fate of chemicals. Chemosphere 1992;24:695-717.
O’Connor DJ. Models of sorptive toxic substances in freshwater systems. III: Streams and rivers. Journal of Environmental Engineering 1988;114:552-574.
Santschi PH, Amdurer M, Adler D, Ohara P, Li YH, Doering P. Relative mobility of radioactive trace elements across the sediment-water interface in the MERL model ecosystems of Narragansett Bay. Journal of Marine Research 1987;45:1007-1048.
Santore RC, Di Toro DM, Paquin PR, Allen HE, Meyer JS. A biotic ligand model of the acute toxicity of metals. II. Application to acute copper toxicity in freshwater fish and daphnia. Environmental Toxicology and Chemistry 2001;20(10):2397-2402
Stephan CE, Mount DI, Hansen DJ, Gentile JH, Chapman GA, Brungs WA. Guidelines for deriving numerical national water quality criteria for the protection of aquatic organisms and their uses. National Technical Information Service, Springfield, VA, 1985, PB85-22-7049.
Tipping E. WHAM - A computer equilibrium model and computer code for waters, sediments, and soils incorporating a discrete site/electrostatic model of ion-binding by humic substances. Computers & Geosciences 1994;20(6):973-1023.
U.S. EPA. Hazard evaluation division, standard evaluation procedure, ecological risk assessment. Washington, DC: U.S. Environmental Protection Agency, Office of Pesticide Programs, June 1986, EPA 540/9-85-001.
U.S. EPA. Quality criteria for water 1986. Washington, DC: U.S. Environmental Protection Agency, 1986, EPA 440/5-86-001.
U.S. EPA. Water quality criteria document for the protection of aquatic life in ambient water 1995 updates. Washington, DC: U.S. Environmental Protection Agency, 1996, EPA 820-B-96-001.
U.S. EPA. Integrated approach to assessing the bioavailability and toxicity of metals in surface waters and sediments. Washington, DC: U.S. Environmental Protection Agency, Science Advisory Board, April 6-7, 1999, EPA-822-E-99-001.
U.S. EPA. A Scientific Advisory Board report: review of the biotic ligand model of the acute toxicity of metals. Washington, DC: U.S. Environmental Protection Agency, Ecological Processes and Effects Committee of the Science Advisory Board, February 2000, EPA-SAB-EPEC-00-0006.
Journal Articles: 4 Displayed | Download in RIS Format
| Other center views: | All 4 publications | 4 publications in selected types | All 4 journal articles |
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Field LJ, Macdonald DD, Norton SB, Ingersoll CG, Severn CG, Smorong D, Lindskoog R. Predicting amphipod toxicity from sediment chemistry using logistic regression models. Environmental Toxicology and Chemistry 2002;21(9):1993-2005. |
R829500 (2002) R829500C001 (2002) R829500C002 (2002) R829500C003 (2002) R829500C004 (2002) R829500C005 (2002) R829500C006 (2002) R829500C007 (2002) |
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Paquin PR, Gorsuch JW, Apte S, Batley GE, Bowles KC, Campbell PGC, Delos CG, Di Toro DM, Dwyer RL, Galvez F, Gensemer RW, Goss GG, Hogstrand C, Janssen CR, McGeer JC, Naddy RB, Playle RC, Santore RC, Schneider U, Stubblefield WA, Wood CM, Wu KB. The biotic ligand model: a historical overview. Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology 2002;133(1-2):3-35. |
R829500 (2002) R829500C001 (2002) R829500C002 (2002) R829500C003 (2002) R829500C004 (2002) R829500C005 (2002) R829500C006 (2002) R829500C007 (2002) |
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Santore RC, Mathew R, Paquin PR, DiToro DM. Application of the biotic ligand model to predicting zinc toxicity to rainbow trout, fathead minnow, and Daphnia magna. Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology 2002;133(1-2):271-285. |
R829500 (2002) R829500C001 (2002) R829500C002 (2002) R829500C003 (2002) R829500C004 (2002) R829500C005 (2002) R829500C006 (2002) R829500C007 (2002) |
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Smith K, Rainville J, Lesher E, Diedrich D, McKnight D, Sofield R. Fractionation of Fulvic Acid by Iron and Aluminum Oxides-Influence on Copper Toxicity to Ceriodaphnia dubia. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014;48(20):11934-11943. |
R829500 (Final) R829515 (Final) |
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Supplemental Keywords:
metal, oxide, aquatic, terrestrial, ecosystems, fate and transport, metal compounds, bioavailability, soil, suspended particles, cost-effective, risk management, safety, regulation, regulatory decisions, decision-making, hazard, risk assessment, persistent organic pollutants,, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Waste, Hazardous, Ecological Risk Assessment, Hazardous Waste, Geochemistry, Ecology and Ecosystems, fate and transport , PCB, remediation, bioaccumulation, extraction of metalsRelevant Websites:
http://www.ce.udel.edu/CSME/Index.html Exit
Progress and Final Reports:
Original Abstract Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R829500C001 Role of Dietary Exposure for Bioaccumulation and Toxicity of Metals in Aquatic Ecosystems Affected by Mining
R829500C002 The Role of Organic Matter and Metal Oxides in the Retention of Trace Metals by Soil and Suspended Particles
R829500C003 Developing a Model to Predict the Persistence of Metals in Aquatic Environments
R829500C004 Effects of Dietary Metal Exposure on Fish and Aquatic Invertebrates
R829500C005 Aquatic Toxicity and Exposure Assessment
R829500C006 Development of a Model to Predict the Bioavailability of Metals to Soil Invertebrates
R829500C007 Bioaccumulation and Toxicity of Dietborne Particulate Metals to Benthic Invertebrates
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.