Grantee Research Project Results
Meiofaunal Validation of EqP-Based Sediment Quality Criteria for Metal Mixtures in Estuarine Sediments Population to Community-Level Culturing Studies of Biogeochemical Controls on Bioavailability and Toxicity
EPA Grant Number: R825279Title: Meiofaunal Validation of EqP-Based Sediment Quality Criteria for Metal Mixtures in Estuarine Sediments Population to Community-Level Culturing Studies of Biogeochemical Controls on Bioavailability and Toxicity
Investigators: Chandler, G. Thomas , Shaw, Timothy J.
Institution: University of South Carolina at Columbia
Current Institution: University of South Carolina at Aiken
EPA Project Officer: Aja, Hayley
Project Period: January 1, 1997 through December 31, 1999 (Extended to December 31, 2000)
Project Amount: $484,376
RFA: Risk-Based Decisions for Contaminated Sediments (1996) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , Land and Waste Management
Description:
The EPA has expended considerable resources over the last 6-8 years developing Equilibrium Partitioning-based (EqP) sediment quality criteria (SQC) for metals (and nonionic organics) that are considered protective of sediment communities in fresh to marine ecosystems. The protection levels of EqP SQC for metals are founded in established EPA water quality chronic-exposure criteria, which are based on "safe" chronic exposure concentrations of metals to water column organisms in llspe single compound:single species bioassays. The validity and protectiveness of single compound-based SQC to multi-species assemblages of benthos should be questioned and studied further because almost all contaminated sediments contain mixtures of toxicants andmixtures of co-inhabiting species. Many metals of toxic concern are released via reduction of oxide phases and/or oxidation of sulfides leading to pore water metal enrichments at the oxic/anoxic sediment interface. Such changes in redox conditions may result in elevated levels of mixed metal concentrations in pore waters with concurrent potential for serious toxic exposures to infauna. In this study, newly-developed meiobenthic single-species, full life-cycle bioassays, and microcosms containing known mixed-species, meiofauna assemblages, will be used to test the protectiveness of EqP SQC for mixed-element exposures of five metals currently regulated by SQC: Cu, Cd, Ni, Pb and Zn. For mixed metal SQC assessments, meiofauna populations from a pristine estuarine preserve will be exposed to 1/5th the summed 0X, 1X, 10X and 100X copepod threshold concentrations derived from single-metal, copepod life-cycle bioassays. Additionally, tagged benthic copepods (Amphiascus tenuiremis) will be used in each microcosm experiment as an internal control to allow measurement of exact, rather than relative, population growth/dynamics. All other sediment-dwelling meiofauna will be assayed for effects on community structure, age-structure, reproduction and population growth. Concurrently, ICP-MS will be used to measure sediment metals as SEM/AVS ratios, and porewater metals/DOC concentrations. This micro/mesocosm approach will provide rapid (14-21d) and precise assessment of sediment-associated contaminant effects on chronic endpoints at the population/community levels. This holistic mixed-metal:mixed-species approach will provide a robust validation of EqP-derived SQC for a model five-metal mixture.Publications and Presentations:
Publications have been submitted on this project: View all 23 publications for this projectJournal Articles:
Journal Articles have been submitted on this project: View all 7 journal articles for this projectSupplemental Keywords:
ocean, environmental health, marine biology., RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Water, Waste, Ecological Indicators, Ecological Risk Assessment, Ecosystem Protection, chemical mixtures, Ecosystem/Assessment/Indicators, Contaminated Sediments, exploratory research environmental biology, Environmental Microbiology, Geochemistry, Ecological Effects - Environmental Exposure & Risk, Biochemistry, Bioavailability, Ecological Effects - Human Health, Chemical Mixtures - Environmental Exposure & Risk, Ecology and Ecosystems, biogeochemical partitioning, marine biology, metal mixtures in estuarine sediments, benthos-associated organisms, contaminated sediment, chronic exposure, sediment quality survey, sediment quality criteria, water quality, aquatic ecosystem, meiofaunal validation, metal release, sediment bioassay, estuarine sediment, aquatic biota, copepod life-cycle bioassays, ecological exposure, equilibrium partitioning based criteria, meiobenthos, oceanProgress and Final Reports:
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.