ABSTRACT:

The Florida Department of Environmental Protection (FDEP) conducts annual probabilistic surveys of Florida’s freshwater resources (flowing waters consisting of rivers, streams, and canals, lakes, and unconfined aquifers). FDEP incorporated organo-nitrogen and organo-phosphorous pesticides, their degradants, and the neonicotinoid imidacloprid into their probabilistic sample surveys for unconfined aquifers in 2015, flowing waters in 2016, and lakes in 2017. Pesticide use intensities (kilograms per hectare) were derived for three classes of pesticides (herbicides, fungicides & insecticides) by creating chloropleth maps of estimated usage versus total agricultural area within 29 drainage basins. Total fresh water concentrations of the most frequently detected pesticides were derived by dissolving data at the sampling locations and aggregating their values. Two graduated symbol maps present these results graphically, one map depicts total number of detections for each sampling location and the other map shows total concentrations of the most frequently detected compounds. The investigation shows the occurrence of these pesticides and their degradants within and among Florida’s freshwater resources and its relationship to pesticide use.