Abstract

 There is increasing support for the use of a "best professional judgment triad" weight of evidence approach for evaluating aquatic sediment quality. This approach is based on an integrated use of sediment toxicity/source of bioaccumulatable chemicals, organism assemblage, and chemical information to determine the potential for constituents in sediments to be adverse to the beneficial uses of the water body in which the sediments are located. This triad approach is a far more reliable approach for evaluating whether a chemical constituent(s) associated with a sediment is adverse to sediment/water quality than a chemical-specific numeric sediment quality guideline. Significant problems occur, however, with the use of this approach by some in incorporating chemical information into the triad. The use of total concentrations of constituents and/or the exceeding of a co-occurrence based so-called sediment quality guideline is technically invalid. Such an approach can distort the triad sediment quality evaluation since it incorporates information into the triad that is not related to the impact of the chemicals on aquatic life-related beneficial uses. The chemical information that should be used in a triad evaluation is that of the chemical forms of the constituents of concern in the sediments that can be adverse to aquatic life. Sediment TIE information should be used as a chemical component of a triad. Examples of appropriate and inappropriate uses of chemical information in a sediment quality BPJ triad are provided.