text: In the United States, the ECOTOX, ERED (sediment) and Toxicity Residue Databases are used by many regulatory agencies such as state environmental quality agencies and the EPA to determine regulatory environmental toxicant concentration levels. Under the Clean Water Act the EPA has used the ECOTOX database among other information to set wastewater toxicant concentration standards for industry as well as water quality standards for all contaminants in surface waters. Under the CWA, individual states must regulate water quality criteria at or below the concentrations set forth by the EPA. Sediment toxicant concentrations, however, are generally not regulated in the same way. The determination of sediment quality criteria and sediment toxicity testing is highly complex and is often regulated by states or some state run environmental agency. Sediment toxicity evaluations of contaminated sediments are very site specific and toxicant effect levels are often much more variable than those of surface waters. For this reason it may be nearly impossible to develop feasible acceptable sediment concentration regulations that apply to all aquatic systems or regions.
  Acceptable concentrations or sediment quality guidelines have been developed and are used in risk assessments and the management of dredged materials. "Sediment quality guidelines" (SQGs), as defined at the 2002 Society of Environmental Toxicology and Chemistry (SETAC) Pellston Workshop, are numerical chemical concentrations intended to be either protective of biological resources, or predictive of adverse effects to those resources, or both. SQGs for assessing sediment quality relative to the potential for adverse effects on sediment-dwelling organisms have been derived using both mechanistic and empirical approaches.