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USE OF CHEMICAL MANIPULATIONS TO ALTER CONTAMINANT BIOAVAILABILITY: SEDIMENT TOXICITY IDENTIFICATION EVALUATION (TIE)
Citation:
Burgess, R M., K T. Ho, M Pelletier, J R. Serbst, S Ryba, M Cantwell, AND M. M. Perron. USE OF CHEMICAL MANIPULATIONS TO ALTER CONTAMINANT BIOAVAILABILITY: SEDIMENT TOXICITY IDENTIFICATION EVALUATION (TIE). Presented at 3rd International Conference on Remediation of Contaminated Sediments, New Orlena, LA, January 24-27, 2005.
Description:
A common method for determining whether contaminants in sediments represent an environmental risk is to perform toxicity tests. Toxicity tests indicate if contaminants in sediments are bioavailable and capable of causing adverse biological effects (e.g., mortality, reduced growth or reproduction) to aquatic organisms. Several environmental management and regulatory programs concerned with contaminated sediments use this approach for assessing risk. However, a limitation of the common toxicity testing approach is that it indicates only if toxicity is present in a given sediment sample. Toxicity test results do not provide information on the cause(s) of toxicity; that is, which specific toxic chemicals are responsible for observed effects. This type of information is of importance in deciding upon remedial actions at contaminated sediment sites. Toxicity Identification Evaluation (TIE) methods were originally developed for use with industrial and municipal effluents to determine the causes of toxicity in waters affected by these discharges. The TIE approach combines toxicity testing with environmental chemistry to selectively alter the bioavailability of specific classes of toxicants in a water or sediment sample. This presentation will focus on recently developed TIE methods for contaminated sediments. By selectively altering the bioavailability of potential toxicants followed by comparison to the toxicity of an unmanipulated sample, it is possible to characterize and identify the causes of sediment toxicity. Currently, interstitial water and whole sediment TIE methods are designed to detect toxicity caused by cationic metals, nonionic organic compounds and ammonia. Also, methods are under development for other toxicants including hydrogen sulfide and anionic metals. This presentation will discuss the specific TIE methods and report the findings of interstitial water and whole sediment TIE studies. The presentation will conclude with applications for interstitial water and whole sediment TIEs as well as research needs for the continued development of sediment TIE methods.