The Role of Risk Management Decisions in the Development of Sediment Quality Guidelines

Sediment quality guidelines (SQGs) are chemical concentrations in sediments that arc assumed to be associated with no or acceptable levels of adverse effects in benthic organisms. They have been proposed and published for numerous chemicals using various methodologies over the past few decades, and their use has inspired considerable debate within the scientific community. One commonly applied methodology for developing SQGs is the compilation and combination of various databases containing sediment chemistry measurements and co-located effects in aquatic organisms (i.e., Effects Range-Low [ER-LJ and Effects Range-Medium [ER-M] values used in the National Oceanographie and Atmospheric Administration Status and Trends Program). This methodology has been adapted recently to derive “consensus-based” SQGs (such as threshold and probable effect concentrations [TECs and PECs]) by compiling and combining previously derived SQGs. The derivation of such SQGs incorporates numerous unstated risk management decisions including the selection of which SQGs to use in the calculation of “consensus-based” SQGs, the choice of method used to determine central tendency, and the interpretation of toxicity test results (such as evaluating multiple species, multiple end-points, and control versus reference locations). Moreover, the application of SQGs to contaminated sediment remediation is also based on unclear risk management decisions. As a result, rather than providing the means for an objective evaluation of sediments, these SQGs and their application incorporate a great deal of subjectivity. The implications of using such SQGs in ecological risk assessments of aquatic systems are discussed.

Julie A. Rothrock and Paul D. Anderson

AMEC Earth and Environmental, Westford, MA

Copyright CRC Press 2004