RESUMO
Neonicotinoid pesticides are highly hydrophilic systemic insecticides that have been extensively used worldwide. To evaluate their environmental risks, the concentrations of these pesticides in the aquatic environment must be monitored. Although the polar organic chemical integrative sampler (POCIS) has proved to be a suitable passive sampler for many highly hydrophilic compounds, Oasis HLB (Waters) POCIS has shown limitations for the monitoring of neonicotinoid pesticides, such as short linear uptake ranges. In the present study we optimized POCIS for neonicotinoid pesticides by selecting suitable adsorbents and filters. The ENVI-Carb (Supelco) nonporous carbon-based adsorbent demonstrated a good balance between strong sorption and high recovery. Static renewal experiments showed that the our POCIS device using ENVI-Carb with a polyethersulfone membrane filter had a 3 d (dinotefuran) to 28 d (clothianidin, imidacloprid, acetamiprid, and thiacloprid) linear range, which is longer than that of HLB POCIS (≤1 [dinotefuran] to 14 d). The POCIS using ENVI-Carb with a polytetrafluoroethylene membrane had higher sampling rates (0.270 L/d [clothianidin] to 0.686 [imidacloprid] L/d) than those of the HLB POCIS for short-term deployment. The time-weighted average concentrations in actual river water measured by the new POCIS were in good agreement with those obtained by repeated grab sampling, within 30%. Moreover, POCIS detected 2 neonicotinoid pesticides that were not detected by grab sampling. Thus, the proposed POCIS is a promising tool for the monitoring of neonicotinoid pesticides. Environ Toxicol Chem 2020;39:1325-1333. © 2020 SETAC.
