Coupling Droplet Drift with Subsequent Volatility Following a Pesticide Application to Address Impact to off-Site Non-Target Organisms.

Pesticides are often a necessary requirement for sustainable and increased agricultural production. This comes at a time when arable farmland is decreasing while the population continues to spiral upward. Agronomic crops are increasingly being bioengineered to tolerate specific herbicides in efforts to minimize weed pressure and ultimately increase agricultural production. Thus, a mechanism to address the impact of pesticides to non-target organisms living at or near the treated field is required to balance the requirements of pesticide use with environmental stewardship. Methodologies to quantify non-target organism exposure and risk must be versatile enough to address short and long term trends as the amounts and types of pesticides fluctuate dependent upon pest outbreaks, pest resistance, and current and future agronomic practices. This work describes a numerical system that investigates transport phenomena through air via coupling both drift deposition (drops) followed by subsequent volatility and air transport (vapor) for a single agriculturally treated field. Existing agricultural exposure models were used (DriftSim, AgDrift, ISCST3, CALPUFF6) and modified (if appropriate), with empirical and theoretical considerations for volatility predictions for deposited pesticide material, to specifically address vapor transport of pesticides. These models can be parameterized by laboratory and field observations or mechanistically based theoretical predictions. Discussions and examples are broken down into volatility categories (medium to low), illustrating the predicted impact of differing BMP’s on non-target exposure. This numerical system is flexible enough for any ingredient in a pesticide formulation, as long as appropriate input parameters that characterize the pesticide/adjuvant are prescribed.