After the persistent, bioaccumulative and toxic properties of legacy pesticides (e.g., organochlorine pesticides) were revealed, the agrochemical industry sought for alternatives of lower environmental impacts. A possible solution emerged in the early 1990s when the discovery of a novel insecticide class was reported. These systemic insecticides act as agonists of the nicotinic acetylcholine receptor, and were hence called neonicotinoids. Their low octanol-water coefficient makes them primarily water-soluble and weakly bioaccumulative. Early studies seemed to indicate relative safety of these compounds to non-target organisms, such as birds or mammals, conferring them a relative popularity in the global agrochemical market. However, recent reports have highlighted the toxicity potential of neonicotinoids, a well-known example being the Colony Collapse Disorder phenomenon that affect natural pollinators such as honeybees. Additionally, many other non-target invertebrates could also be affected, which could in turn impact higher trophic level organisms. These findings have prompted international agencies to establish environment quality standards (EQS) for surface water, which are sometimes above the predicted no effect concentration of aquatic invertebrate species. Therefore, analytical methods whose sensitivity only complies with the current water EQS may be of limited interest to predict the ecotoxicological impact of neonicotinoids. Fast and reliable analytical methods capable of achieving ultra-trace detection are therefore needed. Such sensitivity is rarely if ever achieved in previously published studies that require in addition tedious off-line steps. In the present work, a rapid, sensitive and reliable analytical method was developed for the ultra-trace quantification of neonicotinoid insecticides. The approach relies on automated sample pre-concentration and purification through on-line solid phase extraction coupled to ultra-high performance liquid chromatography tandem mass spectrometry. After optimization of the method robustness factors, the validation step was conducted over a range of aqueous matrices. The application of the newly-developed workflow should document the fate and exposition levels of neonicotinoid insecticides from agricultural water and soils to surface water and drinking water, which could open new avenues to monitor the status and transfer potential of neonicotinoid insecticides at real and effective ranges of concentrations.

Environmental monitoring of systemic insecticides in surface water ecosystems: Development and application of an ultrasensitive and automated analytical method

253rd National Meeting (2017)

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