![[logo] US EPA](../gif/logo_epaseal.gif){kind=logo}
Use of Regional Data to Evaluate and Develop Sediment Quality Guidelines
Steven M. Bay 1, Doris E. Vidal 1, and Peggy L. Myre 2
1 Southern California Coastal Water Research Project, Westminster, California
2 Exa Data and Mapping Services, Edmonds, Washington
Many types of sediment quality guidelines (SQGs) are available for the interpretation of sediment chemistry. However, information describing the accuracy of the different SQGs for predicting sediment toxicity or benthic community degradation is limited, often resulting in controversy regarding which guideline is appropriate for use. One factor further complicating the decision is that site-specific or regional differences in habitat or contamination characteristics may affect the performance of SQGs, thus creating uncertainty regarding their suitability. The availability of synoptic sediment quality data from regional monitoring and other assessment programs provides the opportunity to evaluate SQG performance on a regional level and identify the best SQGs for specific applications.
A dataset consisting of matched coastal southern California sediment chemistry and acute amphipod toxicity measurements for 1100 samples was developed using EMAP and other regional monitoring data, as well as dredge material characterization information. This dataset was used to evaluate the performance of six SQG approaches, including the effects range-median (ERM), consensus median effect concentration (MEC), equilibrium portioning for organics (EqP), apparent effects threshold (AET), and logistic regression model (LRM). The efficiency, sensitivity, and specificity was determined for each SQG. Empirical approaches such as the ERM showed better performance than the EqP and AET. Comparisons with the NOAA Sedtox database indicated that regional differences in the southern California data influenced the performance of the SQGs. The southern California dataset was also used to identify optimized application thresholds for the SQGs and to develop regional guidelines that had improved performance.
Keywords: sediment, sediment quality guideline, toxicity, and chemistry