PT16 Biological Testing Data in Sediment Management Decisions
Exhibit Hall
8:00 AM - Tuesday
(PT258) Changes in the United States Biological Testing Framework for Dredged Material Evaluations.
Steevens, J1, 1 U.S. Army Corps of Engineers, Waterways Experiment Station, Vicksburg, MS, USA
ABSTRACT- Recently, the guidance document entitled Evaluation of Dredged Material Proposed for Discharge in Waters of the United States has undergone significant modifications. The purpose of this revision is to update the approaches and supporting science that are used for evaluating sediments when making management decisions. The previous approach relied on statistical comparisons that resulted in classification of sediments as requiring contaminated sediment management, often when only one biological test result indicated significant toxicity. Restructuring of the approach has led to a more realistic 2-level system that incorporates many of the issues that were raised in the recent SETAC Pellston Workshop on the use of sediment quality guidelines. These changes include the adoption of a weight-of-evidence approach that relies on multiple lines-of-evidence. These lines-of-evidence include biological test data, such as sediment toxicity tests, elutriate tests, and bioaccumulation tests, in addition to analytical chemistry, physical date, and predictive models. Additional non-traditional lines of evidence include the use of analytical screening assays, chronic and sublethal toxicity tests, and enhanced modeling capabilities. Each line of evidence provides information that can be used to develop a comprehensive understanding of contaminant availability, toxicity, and potential for trophic transfer. The weight-of-evidence approach is a risk-based approach that provides a more useful method of assessing the potential for exposure and the probable risk of effects from chemical exposure. The new approach will lend itself to greater flexibility in interpreting biological test data and its subsequent use in making management decisions.
Key words: Contaminated, Dredged Material , Weight-of-Evidence