Equilibrium partitioning sediment guidelines

Development and Application of Equilibrium Partitioning Sediment Guidelines in the Assessment of Sediment PAH Contamination... 

United States Environmental Protection Agency. Methods for the derivation of site-specific equilibrium partitioning sediment guidelines (ESGs)for the protection of benthic organisms nonionic EPA 822-R-00-002 U.S. EPA Office of Water Washington, DC. 2000. 

This last equation forms the basis for the EPA s sediment quality guidelines that are used to assess the potential toxicity of contaminated sediments. The idea is to simply measure Cs and foe, look up K0w in a table, compute the predicted Cw, and compare this result to established water quality criteria for the protection of aquatic life or human life (e.g., carcinogenicity risk factors). The use of this simple equilibrium partitioning expression for this purpose is currently the subject of much debate among scientists as well as policy makers. 

The TU approach, combined with equilibrium partitioning (EqP) and (Q)SAR modeling, was also used by Swartz and DiToro (1997) to develop the XPAII model to predict the toxicity of sediment-associated PAH compounds. A (Q)SAR and EqP method is also presented by Swartz and DiToro (1997) for modeling narcotic chemicals in sediments. In this approach, the sediment quality guideline for a mixture of narcotic chemicals that exhibit additive toxicity could be expressed as the sum of the fraction of the OC-normalized sediment concentrations divided by the SQG for each... 

Number of sediment EQS derivations completed to date 34 interim guidelines Approximately 20, mainly based on equilibrium partitioning Methodologies for metal mixtures, dieldrin, endrin, and PAH mixtures have been published with example calculations and values. 

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