Sediment quality criteria: A review with recommendations for developing criteria for the Hanford Site.

摘要

Criteria for determining the quality of liver sediment are necessary to ensure that concentrations of contaminants in aquatic systems are within acceptable limits for the protection of aquatic and human life. Such criteria should facilitate decision-making about remediation, handling, and disposal of contaminants. Several approaches to the development of sediment quality criteria (SQC) have been described and include both descriptive and numerical methods. However, no single method measures all impacts at all times to all organisms (U.S. EPA 1992b). The U.S. EPA's interest is primarily in establishing chemically based, numerical SQC that are applicable nation-wide (Shea 1988). Of the approaches proposed for SQC development, only three are being considered for numerical SQC on a national level. These approaches include an Equilibrium Partitioning Approach, a site-specific method using bioassays (the Apparent Effects Threshold Approach), and an approach similar to EPA's water quality criteria (Pavlou and Weston 1984). Although national (or even regional) criteria address a number of political, litigative, and engineering needs, some researchers feel that protection of benthic communities require site-specific, biologically based criteria (Baudo et al. 1990). This is particularly true for areas where complex mixtures of contaminants are present in sediments. Other scientifically valid and accepted procedures for freshwater SQC include a background concentration approach, methods using field or spiked bioassays, a screening level concentration approach, the Apparent Effects Threshold Approach, the Sediment Quality Triad, the International Joint Commission Sediment Assessment Strategy, and the National Status and Trends Program Approach. The various sediment assessment approaches are evaluated for application to the Hanford Reach and recommendations for Hanford Site sediment quality criteria are discussed.