Development of Methodology for Determining Risk Assessment When Sludge is Applied to Land

摘要

This project explored the feasibility of developing a risk assessment methodology that could be applied to sludge management decision making. It examined cadmium, since this substance is one of the best studied and most extensively reported contaminants. The methodology developed allows determination of the proportion of the population experiencing given levels of exposure to a toxic substance under specified management strategies. In addition, it provides for the evaluation of the damage caused by such exposure. When both the dosage-response analysis and the exposure population analysis are joined, the distribution of population into levels of response can be established. Each requires separate categories data. The first is the result of controlled experiments and carefully designed epidemiological statistical studies. The second consists of ongoing data bases on a national scale, including both measurements of background levels of the toxic substance and data on the actual levels at the various stages of the disposal and dispersal procedures. This report establishes that these data bases are required. The problems associated with both categories of data are considered and discussed.