Sediment Quality Criteria: Numeric Chemical– vs. Biological Effects–Based Approaches

The US EPA and state regulatory agencies are developing sediment quality criteria and standards for the protection of water quality from sediment-associated contaminants. Many of the approaches being pursued rely in whole or substantive part on the bulk concentrations of selected chemical contaminants in the sediment as a basis for determining those sediments sufficiently contaminated to warrant remedial action. Principles of aqueous environmental chemistry and toxicology of chemical contaminants and practical experience demonstrate that such an approach is an unreliable basis for assessing potential water quality impacts of sediment-associated contaminants. Instead, assessments should be made on the basis of biological effects that are related to beneficial uses of the receiving water. This paper summarizes technical deficiencies with current approaches for sediment quality criteria and standards development and suggests an alternative, biological effects-based approach that utilizes existing well-established procedures for the evaluation and management of contaminated sediments.