Incorporating the benefits of vegetative filter strips into risk assessment and risk management of pesticides

Abstract

The pesticide registration process in North America, including the United States and Canada, involves conducting a risk assessment based on relatively conservative modeling to predict pesticide concentrations in receiving waterbodies. The modeling framework does not consider some commonly adopted best management practices that can reduce the amount of pesticide that may reach a waterbody, such as vegetative filter strips (VFS). Currently, VFS are being used by growers as an effective way to reduce off‐site movement of pesticides and they are being implemented on pesticide labels as a mitigation measure. Given the regulatory need, a pair of multi‐stakeholder workshops were held in Raleigh, North Carolina to discuss how to incorporate VFS into pesticide risk assessment and risk management procedures within the North American regulatory framework. Because the risk assessment process depends heavily on modeling, one key question was how to quantitatively incorporate VFS into the existing modeling approach. Key outcomes from the workshops include the following: VFS have proven effective in reducing pesticide runoff to surface waterbodies when properly located, designed, implemented and maintained; Vegetative Filter Strip Modeling System (VFSMOD), a science‐based and widely validated mechanistic model, is suitable for further vetting as a quantitative simulation approach for pesticide mitigation with VFS in current regulatory settings; and VFSMOD parametrization rules need to be developed for the North American aquatic exposure assessment.