Grant: Engage Grants Program

We are developing a new passive water sampler to measure the neonicotinoid insecticide thiamethoxam, and will use it to evaluate sources as well as input and elimination rates of this chemical from the lower Red River watershed in Manitoba. Neonicotinoids are typically applied as treatments on seeds, and provide protection for crop plants as they grow and mature. They can leach from seeds and be released into the aquatic environment via processes such as runoff of water from fields. These insecticides are very toxic to pollinating insects, such as bees. They are extremely controversial because some claim that they are responsible for die-offs of bee colonies, which can result in significant economic losses. However, it is not at all clear if these die-offs are due to the presence of neonicotinoids, or other factors such as loss of grazing habitat for bees. Indeed, there is relatively little known about how these chemicals behave in environmental waters. This is due, in part, to the fact that most monitoring programs for pesticides take discrete grab samples. While useful, this form of sampling can provide no information about chemicals for which concentrations can change significantly over time, such as pesticides during different parts of the growing season. Passive samplers, on the other hand, can uptake chemicals using no moving parts or power, to provide a continuous time-weighted-average concentration that would result in better monitoring of chemicals of concern. In partnership with Sygenta Canada, Inc., we are evaluating the organic Diffusive Gradients in Thin Films (o-DGT) passive water sampling device. Unlike other samplers, the rate at which o-DGT collects chemicals only depends on its diffusion rate, which can be measured and predicted. It does not depend on factors such as water flow that can be difficult to predict. We will calibrate this device in the laboratory for neonicotinoids, and determine input and removal rates of this chemical in a representative Canadian watershed. This work would provide Canadians with knowledge of a sampler invaluable for contaminant monitoring studies, and insights into the factors affecting levels of this insecticide in our waters for better environmental protection.