As population increases and society becomes more complex, scientifically based risk assessments are assuming increasing importance in determining how society treats its agriculture. The risk assessments used to develop regulations for urban sewage sludge as a soil amendment on agricultural lands are an interesting and important case in this regard.
Despite the mundane and unpleasant character of sewage sludges, their disposal is a serious social and scientific issue. (Sewage sludge is composed of the solids and liquids which remain after treatment by modern wastewater treatment plants.) Because sludges contain a multitude of inorganic, organic, and biological pollutants that flow down the urban drain, determining the risks associated with their use as a soil amendment for agriculture poses serious difficulties
Restrictions on ocean dumping of urban wastes has made disposal of sludges a substantial problem. In 1987 the US Congress mandated the Environmental Protection Agency (EPA) to develop standards for the land application of sludge. In 1993, the US EPA published the new "Standards for the Use or Disposal of Sewage Sludge (40CFR part 503)." To develop these regulations the US EPA engaged in an extended and complex risk assessment of fourteen exposure pathways. In comparison to those current in Europe and Canada, the new US EPA standards dramatically increase allowable concentrations of pollutants in land applied sludges.
Since that time social and scientific debate has surrounded the new regulations. This panel will elucidate the domestic and international controversy associated with the US EPA sludge risk assessments and the regulations derived from them.
Al Medvitz (Rio Vista, CA). Medvitz has been a rancher and farmer raising lambs and dryland grains on the western edge of California's central valley for the past 11 years. He is active in the state and local farm community on matters of land use, marketing, and environmental issues. Prior to farming, he was on the faculty at Boston University.
Murray McBride and David Bouldin (Dept. of Soil Crop and Atmospheric Science, Cornell University). McBride is a Professor of Soil Chemistry in the Dept. of Soil Crop and Atmospheric Sciences at Cornell University. He has a PhD from Michigan State University. His 25 year research career has a focused on the chemistry of trace elements, toxic heavy metals, and organic chemicals in soils and clay materials. Bouldin is Professor Emeritus in the Dept. of Soil Crop and Atmospheric Sciences at Cornell University.
Lewis is a research microbiologist. He received a PhD from U. of Georgia in ecology.
Uta Krogmann (Rutger U, Cook College) and Ellen Harrison (Cornell U). Krogmann is an Assistant Professor and Extension Specialist in solid waste management at Rutgers University, Cook College. She received her PhD in Civil Engineering from the Dept. of Urban Environmental Technologies, TUHH, Hamburg Germany. Harrison is Director of the Cornell Waste Management Institute, a program of the Center for the Environment at Cornell University. She received her Master's in geology from Cornell.
Michael Baram (Boston U). Baram is a Professor of Law and the Director of the Center for Law and Technology at Boston University Law School. He is also a partner in the firm of Bracken and Baram. His specialty is environmental law and corporate liability. He has served on several National Academy of Sciences committees including the panel that evaluated the land application rules.