The Ambient Water Quality Criteria that were promulgated by the U.S. Environmental Protection Agency in 1980 included water concentration levels which, for many pollutants, were so low as to be unmeasurable by standard analytical methods. Criteria for controlling toxics in municipal sludge would likely pose similar problems of sampling and analysis. Risk assessment methodologies recently developed by the U.S. EPA provide criteria derivation procedures for each of the following sludge management practices: land application (including distribution and marketing), landfilling, incineration, and ocean disposal. These methodologies recommend that numerical limits on toxicant concentrations in sludge, or on rates of toxicant disposal, should be used to minimize risk to human health and the environment. Implementation of these numerical criteria would require refinement of sampling and analytical techniques for sludges, and various types of field validation studies would be needed to ensure that the criteria are appropriately protective.

Caption title. "EPA/600/D-89/031." "Presented in: Chemical and Biological Characterization of Sludges, Sediments, Dredge Spoils and Drilling Muds, ASTM STP 976, J.J. Lichetenberg etal, EDS., American Society for Testing and Materials, Philadelphia, PA 1988, pp. 465-471." Microfiche.