US EPA

Risk assessment methods have been developed which can be used to calculate criteria for controlling toxic pollutants in municipal wastewater sludges. hese methods consist of algorithms, ranging from simple to complex, which allow calculation of exposure and risk from various sludge disposal practices. hese calculations may show a need for management practice controls or for numerical limits on specific pollutants. Criteria for land-applied or distributed and marketed sludge may take the form of application rate limits (kg/ha) or concentration limits, calculated to control pollutant levels in the food chain or off-site movement in air or water. riteria for landfilled sludge are defined in term of acceptable leachate concentrations, as determined by an appropriate leachate characterization test, to prevent excessive groundwater contamination of vapor emission. ncineration criteria are expressed as limitations on stack emission rates (g/sec), based on predicted air concentrations at ground level. riteria for sludge which is ocean-disposed at the 106-Mile Site are calculated in terms of sludge concentration and total daily pollutant input to the site, in order to protect marine life and human consumers of seafood. hese risk assessment methods were developed in a research environment in order to promote scientific consistency in the regulatory process.

Bruins, R., L. Fradkin, AND J. Stara. SUMMARY OF RISK ASSESSMENT METHODOLOGIES FOR MUNICIPAL SLUDGE REUSE OF DISPOSAL OPTIONS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/D-89/016 (NTIS PB89218168).

In: Proceedings of the National Conference on Municipal Sewage Treatment Plant Sludge Management, Series No. 17, Hazardous Materials Control Res. Inst., Silver Spring, MD, 1987, pp.21-24