Sorbent impregnated polyurethane foam disk passive air samplers for investigating current-use pesticides at the global scale

A pilot study conducted at a subset of 20 sites operated under the GAPS (Global Atmospheric Passive Sampling) Network compared the performance of two types of passive samplers for measuring air concentrations of currently–used pesticides, during 3–month deployment periods. The conventional polyurethane foam (PUF) disk sampler was able to capture a range of targeted current–use pesticides CUPs (dacthal, trifluralin, chlorothalonil, chlorpyrifos, and pendimethalin) but experienced equilibrium for some compounds (dacthal, trifluralin, and chlorothalonil) during the deployment period. The second sampler type used was a modified PUF disk sampler impregnated with XAD powder [i.e. the SIP (sorbent–impregnated PUF) disk] to increase sorptive capacity. The SIP disk sampler accumulated greater amounts of most targeted CUPs when compared to the PUF disk sampler. Results of the study showed that chlorothalonil was the most abundant CUP reflecting its widespread use, globally; whereas dacthal exhibited greater global distribution, including presence at remote sites, reflecting its high potential for long–range atmospheric transport. A thorough calibration of both the PUF disk and the SIP disk samplers is required to further define uptake profiles and to determine their range of applicability for various CUPs.