title: Method for testing the aquatic toxicity of sediment extracts for use in identifying organic toxicants in sediments.
abstract: Biologically directed fractionation techniques are a fundamental tool for identifying the cause of toxicity in environmental samples, but few are available for studying mixtures of organic chemicals in aquatic sediments. This paper describes a method for extracting organic chemicals from sediments and then re-introducing them into water column toxicity tests in a way that mimics, at least in part, the partitioning processes that govern bioavailability in sediment. This involves transferring solvent extracts of sediment into triolein and then placing the mixture inside low-density polyethylene dialysis tubing in a configuration similar to semipermeable membrane devices (SPMDs) used for environmental monitoring. For four model compounds, SPMDs were shown to effectively maintain water column exposure in static systems for 10-14 d, with partition coefficients similar to K(OW). Toxicity tests indicated that the SPMDs were compatible with four of five freshwater organisms tested and could be used to measure both lethal and sublethal end points. An example application showed good correspondence between organism responses in intactsediment and extracts in SPMDsfor both field-collected and spiked sediments. The SPMD-based method offers a simple, flexible test design, amenable to several different test organisms, and the ability to work with complex mixtures of contaminants while maintaining partitioning behavior similar to that within intact sediments.
authors.affiliation: US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Laboratory, Mid-Continent Ecology Division, Duluth, Minnesota 55804, USA.
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Heinis
authors.forename: Terry L
authors.initials: TL
authors.lastname: Highland
authors.forename: David R
authors.initials: DR
authors.lastname: Mount
mesh_terms: D000818:Animals; D001682:Biological Availability; D018533:Biomass; D004026:Dieldrin / Q000633:toxicity*; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D005618:Fresh Water / Q000737:chemistry; D019015:Geologic Sediments / Q000737:chemistry*; D008567:Membranes, Artificial; D009930:Organic Chemicals / Q000032:analysis* / Q000493:pharmacokinetics / Q000633:toxicity; D018675:Toxicity Tests; D014304:Triolein / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000493:pharmacokinetics / Q000633:toxicity
chemical_list: D008567:Membranes, Artificial; D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; D014304:Triolein; D004026:Dieldrin