EPA Science Inventory

PREDICTING SEDIMENT METAL TOXICITY USING A SEDIMENT BIOTIC LIGAND MODEL: METHODOLOGY AND INITIAL APPLICATION

Citation:

DI TORO, D. M., J. A. MCGRATH, D. J. HANSEN, W. J. BERRY, P. R. PAQUIN, R. MATHEW, K. B. WU, AND R. C. SANTORE. PREDICTING SEDIMENT METAL TOXICITY USING A SEDIMENT BIOTIC LIGAND MODEL: METHODOLOGY AND INITIAL APPLICATION. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 24(10):2410-2427, (2005).

Description:

An extension of the simultaneously extracted metals/acid-volatile sulfide (SEM/AVS) procedure is presented that predicts the acute and chronic sediment metals effects concentrations. A biotic ligand model (BLM) and a pore water–sediment partitioning model are used to predict the sediment concentration that is in equilibrium with the biotic ligand effects concentration. This initial application considers only partitioning to sediment particulate organic carbon. This procedure bypasses the need to compute the details of the pore-water chemistry. Remarkably, the median lethal concentration on a sediment organic carbon (OC)–normalized basis, SEM*x,OC, is essentially unchanged over a wide range of concentrations of pore-water hardness, salinity, dissolved organic carbon, and any other complexing or competing ligands. Only the pore-water pH is important. Both acute and chronic exposures in fresh- and saltwater sediments are compared to predictions for cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) based on the Daphnia magna BLM. The SEM*x,OC concentrations are similar for all the metals except cadmium. For pH = 8, the approximate values (μmol/gOC) are Cd-SEM*x,OC 100, Cu-SEM*x,OC 900, Ni-SEM*x,OC 1,100, Zn-SEM*x,OC 1,400, and Pb-SEM*x,OC 2,700. This similarity is the explanation for an empirically observed dose–response relationship between SEM and acute and chronic effects concentrations that had been observed previously. This initial application clearly demonstrates that BLMs can be used to predict toxic sediment concentrations without modeling the pore-water chemistry.

Purpose/Objective:

To present an extension of the simultaneously extracted metals/acid-volatile sulfide (SEM/AVS) procedure that predicts the acute and chronic sediment metals effects concentrations

Record Details:

Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Start Date: 10/01/2005
Completion Date: 10/01/2005
Record Last Revised: 08/07/2006
Record Created: 10/18/2005
Record Released: 10/18/2005
OMB Category: Other
Record ID: 141710

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LAB

ATLANTIC ECOLOGY DIVISION