Pesticide risk benefit analysis in drinking water and management implications

Water quality monitoring performed under the Safe Drinking Water Act at most community water systems is typically limited to four data points per year over a few years. Due to this limited sampling, likely maximum residues may be underestimated in risk assessment. In the first part of this dissertation, a statistical methodology is proposed to study both cross-sectional and longitudinal uncertainties in observed samples and their propagated effect in risk estimates. The second part of the dissertation provides an improved methodology for investigating the trade-offs between the health risks and economic benefits of using atrazine in the agricultural sector by incorporating public attitude to pesticide management in the analysis. Analysis of different scenarios indicate that if the society is willing to pay a price premium, risks can be reduced without a large reduction in the total economic surplus while net benefits may be higher. Finally, when a pesticide is banned, in an effort to reduce pesticide-related risk to the public, substitute pesticide(s) with different risks would likely replace the risk from the banned pesticide. About 80% of atrazine will likely be replaced by 2,4-D, bromoxynil, dicamba, and nicosulfuron. We found that banning atrazine will increase the risk from these substitute pesticides, but the cumulative risk from atrazine and the substitutes actually decreased slightly after the ban. The third part of the dissertation provides a framework that may be used as a regulatory decision support tool in studying the effect of banning a pesticide at the national level. In summary, this dissertation provides a scientific framework for uncertainty analysis, risk benefit analysis at national scale by incorporating social values, decision-making and policy implementation related to managing a pesticide of concern.