Grantee Research Project Results
Final Report: Development of Arsenic Sediment Quality Criteria using Equilibrium Partitioning
EPA Grant Number: R830844Title: Development of Arsenic Sediment Quality Criteria using Equilibrium Partitioning
Investigators: Visviki, Ioanna , Mahony, John D. , Carbonaro, Richard F. , Judge, Michael L.
Institution: College of Mount Saint Vincent
EPA Project Officer: Hahn, Intaek
Project Period: June 27, 2003 through June 26, 2005 (Extended to June 26, 2006)
Project Amount: $389,391
RFA: Superfund Minority Institutions Program: Hazardous Substance Research (2002) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , Safer Chemicals , Land and Waste Management
Objective:
The objective of this research project is to test the applicability of the equilibrium partitioning (EqP) method for developing quality criteria for arsenic in sediments. Arsenic in aquatic sediments is currently a significant problem at Superfund sites. However, reliable methods for determining the sediment concentrations at which arsenic poses an environmental risk are lacking. The EqP method relates the observed toxicity of a chemical in the sediment to the concentration of that chemical in the pore water of the sediment. The toxicity of various chemical species can be determined using water-only exposures and the results applied to pore water. The EqP model predicts that if the measured pore water concentration is less than the LC50 concentration determined from the water-only exposures, then no mortality should be observed. We tested the equilibrium-partitioning model for arsenic via three approaches: (1) Microtox screening assays for potential chemical interactions with sulfide compounds; (2)96-hour static renewal toxicity tests to determine water-only LC50s for the marine amphipod Leptocheirus plumulosus; and (3) 10-day spiked sediment tests with amphipods under oxic and anoxic conditions.
Summary/Accomplishments (Outputs/Outcomes):
Microtox
We determined the concentrations of As (V), As (III), and sulfides, which reduced the bioluminescence of Vibrio fisheri by 50 percent (EC50), using Microtox. After 30 minutes of exposure the trivalent form was shown to be more toxic than the pentavalent form. The EC50 for As (III) was 1.101 mg/L, whereas for As (V) it was 2.110 mg/L. These results are congruent with those previously obtained with the amphipod L. plumulosus. Sulfides had an EC50 of 311 mg/L. Exposure to As (III) and sulfide mixture indicated that the presence of sulfides decreased the toxicity of trivalent arsenic, shifting its EC50 to 1.725 mg/L but increased the toxicity of the pentavalent form to 0.796 mg/L.
96-Hour Toxicity Tests With Amphipods. The water-only LC50 for As (III) has been calculated at 700 μg/L. The LC50 for As (V) is over three times higher at 2400 μg/L.
10-Day Spiked Sediment Tests With Amphipods. We conducted 10-day experiments with amphipods evaluating the toxicity of As (III) in natural sediments at various sulfide concentrations to test the predictions of EqP. Exposure to As (III) in sediments in the presence of sulfides decreased amphipod mortality ten-fold and shifted the LC50 to 8000 ug/L. Therefore, our results support the predictions of the EqP for arsenite.
Journal Articles:
No journal articles submitted with this report: View all 17 publications for this projectSupplemental Keywords:
arsenic (III), arsenic (V), sulfides, Leptocheirus plumulosus, amphipods, equilibrium partitioning, aquatic ecosystem, ecotoxicology, heavy metals,, Health, RFA, Scientific Discipline, Water, Waste, POLLUTANTS/TOXICS, Risk Assessments, Environmental Chemistry, Contaminated Sediments, Geochemistry, Arsenic, Water Pollutants, arsenic mobility, contaminant transport, equilibrium partitioning, assessment methods, contaminated sediment, sediment quality survey, water quality, EqP, biogeochemistry, bioaccumulation, sediment transport, water treatment, ecology assessment models, superfund site, reservoir sediments, risk management, arsenic exposureProgress and Final Reports:
Original AbstractThe 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.