Pesticide hotspot probability model

A high density of shallow pore water screening samples taken for a pesticide contamination study were applied to the development of a probability model spreadsheet. The JAGG model 1.5, developed by the Danish Environmental Protection Agency, was modified to pore water sampling instead of soil gas, to output the number of pore water samples necessary to detect a pesticide hotspot with a defined level of certainty. The spreadsheets calculate the grid size (representing one pore water sample per grid cell) required to detect a pesticide of a defined concentration at a defined certainty. In this study, the probability model was run for several concentration levels of two dominant pesticides, desphenyl choridazone (DPC) and mechloroprop (MCPP). The results of the spreadsheet provide a starting point for similar studies to locate and delineate pesticide contamination areas, and investigate the conceptual understanding of the contamination area.