Primary prevention of chemical contamination.

The current approach to addressing health and ecosystem risks from biosolids, or sludge, requires identification of so-called "safe" or "acceptable" levels of exposure and installation of controls to achieve such levels. This end-of-the pipe approach is inconsistent with the public health concept of primary prevention. Following an overview of the limitations in current approaches to understand and address risks of biosolids contamination, we present a new, preventative paradigm for addressing the hazards of sludge. We conclude that given the disparate and widely distributed sources of contaminants in biosolids and the amount of uncertainty in information about health and environmental effects, we need a new approach to this and other environmental dilemmas. This approach is embodied in the concept of the precautionary principle and public health goal-setting.