| Abstract: | Organic solvents are commonly used in many sediment toxicity bioassays to facilitate the extraction and concentration of adsorbed contaminants from sediment samples. However, the inherent biotoxicity of most solvents to the bioassay organism may complicate greatly the interpretation of the toxicity test results. To alleviate this problem, a solvent-less extraction procedure was developed for use in the assessment of sediment toxicity. Basically, it involves the use of sonication and sodium ligninsulfonate to enhance the release of the adsorbed contaminants from the sediment. The procedure was applied to sediment samples collected from the St. Clair River at a site approximately 25 m offshore of Dow Chemicals (Sarnia, Ontario). Test results indicate that the most toxic components of the St. Clair River system near Dow Chemicals were associated mainly with the sediment fraction, and there appeared to be very little or no biotoxicity in the overlaying water column. Several of the major contaminants were identified as chlorinated hydrocarbons. The impact of these chemicals on the aquatic environment is discussed. © 1996 by John Wiley & Sons, Inc. |
