Grantee Research Project Results
2004 Progress 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 , Manhattan College
Current 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 Period Covered by this Report: June 27, 2004 through June 26, 2005
Project Amount: $389,391
RFA: Superfund Minority Institutions Program: Hazardous Substance Research (2002) RFA Text | Recipients Lists
Research Category: Land and Waste Management , Safer Chemicals , Hazardous Waste/Remediation
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 currently is a significant problem at Superfund sites. Reliable methods, however, for determining the sediment concentrations at which arsenic poses an environmental risk, especially in the presence of sulfides, 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 EqP model is tested using three approaches: (1) Microtox screening assaysto establish potential chemical interactions of arsenic with sulfide compounds; (2) 96-hour water-only exposures to determine the LC50 concentrations of As(III) and As(V) with amphipods; and (3) 10-day amphipod tests with As(III) or As(III)/sulfide spiked sediments.
Progress Summary:
I. 96-Hour Toxicity Tests With Amphipods
Definitive tests with As(V) showed that the LC50 concentration is 2,400 μg/L; approximately 3 times higher than the LC50 for As(III).
II. Microtox
We determined the concentrations of As(V), As(III), and sulfides that reduce 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 1.439 mg/L. These results are congruent with those previously obtained with the amphipod Leptocheirus plumulosus. As(III) was 3.4 times more toxic, however, toward the amphipod, but it was only 1.3 times as toxic as As(V) toward the bacterium. Sulfides had an EC50 of 311 mg/L. Exposure to As(III) and a sulfide mixture indicated that the presence of sulfides decreased the toxicity of trivalent arsenic after 30 minutes of exposure but increased the toxicity of the pentavalent form.
Partitioning of Arsenic (From HM3AsO3) in Artificial Sediment
We determined the pore water arsenic concentrations over a 10-day period as a function of varying sediment arsenic loads. We examined the effects of batch renewals on arsenic concentration in the overlying water and investigated the role of aeration and feeding regime on sulfide levels in the sediment. We concluded that single batch renewal was required to reduce overlying water As(III) levels below the LC50 concentration before the organisms were added. One day of aeration was necessary to make the overlying water oxic and appropriate for Leptocheirus. Feeding did not contribute any appreciable concentrations of sulfides. Equilibration of As(III) in sediments required 1 week.
Future Activities:
We will investigate the relationship of As(V) and sulfides as a function of time using Microtox. We will conduct 10-day experiments with amphipods by evaluating the toxicity of As(III) in natural sediments at various sulfide concentrations to test the predictions of equilibrium partitioning.
Journal Articles:
No journal articles submitted with this report: View all 17 publications for this projectSupplemental Keywords:
arsenic (III), arsenic (V), sulfides, Microtox, Vibrio fisheri, Leptocheirus plumulosus, amphipods, equilibrium partitioning, aquatic ecosystem, ecotoxicology,, RFA, Health, Scientific Discipline, Waste, Water, POLLUTANTS/TOXICS, Contaminated Sediments, Environmental Chemistry, Geochemistry, Arsenic, Risk Assessments, Water Pollutants, reservoir sediments, contaminant transport, Superfund sites, contaminated sediment, sediment transport, risk management, EqP, sediment quality survey, superfund site, arsenic mobility, assessment methods, water quality, ecology assessment models, biogeochemistry, water treatment, arsenic exposure, equilibrium partitioningRelevant Websites:
http://www.profweb.ws/~ioanna.visviki/research.htm Exit
Progress 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.