NANOPESTICIDE FATE AND TRANSPORT IN AGROECOSYSTEMS

Nanopesticides are an emerging class of pesticides associated with engineered nanoparticles that provide agricultural and environmental benefits. However, nanopesticide fate, transport, and persistence remain poorly understood. As do their potential impacts on the health of agroecosystems and influence on nutrient release. Therefore, this project investigated the fate, transport, and persistence of two widely available nanopesticides, an insecticide, nano-imidacloprid, and a fungicide, nano-copper hydroxide. The fate and transport in runoff water and soils of these nanopesticides, as well as their impacts on nutrients retention, were assessed through a field plot study over 2 growing seasons. Runoff from rainfall events and soil samples in 30 field plots with a combination of pesticide applications and a control were analyzed for pesticides and nutrients levels in replicates of six. Runoff of both pesticides was minimal, however, imidacloprid was observed to be primarily transported during the first flush rainfall event. Additionally, in the 2nd growing season under smaller rainfall events nano-imidacloprid was found to be transported less than standard imidacloprid. In contrast, nano-copper showed little runoff response, remaining in the soil after the growing season, but increased the export of both nitrogen and phosphorus species. Additionally, imidacloprid was observed to suppress runoff of copper from the field plots. These findings emphasize the necessity of properly timing imidacloprid application to prevent immediate losses to runoff, as well as the risks of continuous copper applications to soil productivity.