PURE: a web-based decision support system to evaluate pesticide environmental risk for sustainable pest management practices in California.

Farmers, policy makers, and other stakeholders seek tools to quantitatively assess pesticide risks for mitigating pesticide impacts on ecosystem and human health. This paper presents the Pesticide Use Risk Evaluation (PURE) decision support system (DSS) for evaluating site-specific pesticide risks to surface water, groundwater, soil, and air across pesticide active ingredient (AI), pesticide product, and field levels. The risk score is determined by the ratio of the predicted environmental concentrations (PEC) to the toxicity value for selected endpoint organism(s); except that the risk score for the air is calculated using the emission potential (EP), which is a pesticide product property for estimating potential volatile organic compound (VOC) emissions by California Environmental Protection Agency (CEPA). The risk scores range from 0 to 100, where 0 represents negligible risk while 100 means the highest risk. The procedure for calculating PEC in surface water was evaluated against monitoring data for 41 pesticide AIs, with a statistically significant correlation coefficient of r=0.82 (p<0.001). In addition, two almond fields in the Central Valley, California were evaluated for pesticide risks as a case study, where the commonly acknowledged high-risk pesticides gained high risk scores. Simazine, one of the most frequently detected pesticides in groundwater, was scored as 74 (the moderate high risk class) to groundwater; and chlorpyrifos, one of the frequently detected pollutants in surface water, was scored as 100 (the high risk class) to surface water. In support of pesticide risk quantitative assessment and use of reduced-risk pesticide selection, the PURE-DSS can be useful to assist growers, pesticide control advisors, and environmental protection organizations in mitigating pesticide use impacts on the environment.