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TOXICITY CHARACTERIZATION PROCEDURES FOR ORGANIC TOXICANTS IN BULK SEDIMENTS
Citation:
Mount, D. R., L J. Heinis, T L. Highland, V R. Mattson, T J. NorbergKing, AND E N. Leonard. TOXICITY CHARACTERIZATION PROCEDURES FOR ORGANIC TOXICANTS IN BULK SEDIMENTS. Presented at 22nd Annual SETAC Meeting, Baltimore, MD, November 11-15, 2001.
Description:
We have been pursuing development of toxicant characterization, isolation, and identification procedures for organic toxicants that can be applied in the context of 10-d solid-phase sediment tests measuring survival and growth of freshwater in the context of 10-d solid-phase sediment tests measuring survival and gowth of freshwater invertebrates. Characterization tests have focused on materials to sorb organic toxicants from interstitial water. Ambersord 1500 has been shown to be effctive at reducing toxicity and/or interstitial water concentrations of several organic chemicals in solid phase tests. Unfortunately, this resin is no longer available. Two other Ambersol resins, 563 and 572, do not appear to be as effective at reducing toxicity. Experiments with coconut charcoal indicate that chemical sorption improves with decreasing particle size, but smaller particle sizes are also associatedwith artifactual toxicity in clean sediment to which they are added. Effectiveness depends on balancing sorption efficiency against organism tolerance of the charcoal addition. While these characterization tests use a sorption approach, isolation and identification work has centered on the use of semi-permeable membrane devices (SPMDs) into which sediment extracts are placed. These SPMDs serve as chemostats for waterborne exposures, creating exposure concentrations similar to those observed in intact sediments while allowing for fractionation studies to be conducted on the extracts. This approach is much more time- and resource-effective than respiking extracts onto clean sediments as we have done in the past.