SYMPOSIA PAPER Published: 01 January 1988

An Evaluation of the Screening Level Concentration Approach for Validation of Sediment Quality Criteria for Freshwater and Saltwater Ecosystems


The U.S. Environmental Protection Agency (EPA) has initiated an effort to develop sediment quality criteria for both freshwater and marine ecosystems. The Screening Level Concentration (SLC) approach is one of several methods EPA is evaluating for calculating sediment quality criteria. The SLC approach uses field data on the cooccurrence in sediments of benthic infaunal invertebrates and different concentrations of the nonpolar organic contaminant of interest. The SLC method is designed to estimate the highest concentration (normalized to sediment organic carbon concentration) of a particular nonpolar organic contaminant in sediments that can be tolerated by approximately 95% of benthic infauna. As such, the SLC value could be used in a regulatory context as the concentration of a contaminant in sediment that, if exceeded, could lead to environmental degradation.

This paper describes the method for calculating the SLC and evaluates the SLC approach empirically for nonpolar organic contaminants in freshwater and marine sediments in terms of its statistical properties and its dependence on the characteristics of the data base. SLCs are calculated for five contaminants in freshwater sediments (total polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane (DDT), dieldrin, chlordane, and heptachlor epoxide) and nine contaminants in saltwater sediments (total PCBs, DDT, naphthalene, phenanthrene, fluoranthene, benz(a)anthracene, chrysene, pyrene, and benzo(a)pyrene). The method used to calculate SLCs is illustrated for total PCBs in freshwater and saltwater sediments. Differences in SLC values for PCBs and DDT between freshwater and saltwater sediments are discussed. The SLC approach demonstrates sufficient merit to warrant further evaluation and elaboration. Given a large enough data base and minor modifications of the methods for calculating an SLC for a specific contaminant, the approach can provide a conservative estimate of the highest concentration, normalized to sediment organic carbon, that 95% of the benthic infauna can tolerate in sediment.

Author Information

Neff, JM
Battelle, Department of Ocean Sciences, Duxbury, MA
Cornaby, BW
Battelle, Department of Environmental Sciences, Columbus, OH
Vaga, RM
Battelle, Department of Environmental Sciences, Columbus, OH
Gulbransen, TC
Battelle, Department of Ocean Sciences, Duxbury, MA
Scanlon, JA
Battelle, Department of Ocean Sciences, Duxbury, MA
Bean, DJ
Battelle, Department of Environmental Sciences, Columbus, OH
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Developed by Committee: E47
Pages: 115–127
DOI: 10.1520/STP34034S
ISBN-EB: 978-0-8031-5043-0
ISBN-13: 978-0-8031-0978-0