Neonicotinoid insecticides (NEOs) are emerging pesticides of concern due to their potential toxicity to non-target species (e.g., bees, fish and birds). As an important producer and user of NEOs, China has very limited information on human exposure to NEOs. Therefore, we first conducted a nationwide survey, indicated a widespread exposure to NEOs in China. Total urinary NEO concentrations (ΣNEOs; sum of six NEOs) were dominated by clothianidin (CLO, median: 0.24 ng/mL), imidacloprid (IMI, 0.21 ng/mL), thiamethoxam (THM, 0.15 ng/mL) and dinotefuran (DIN, 0.14 ng/mL) collectively accounting for 98% of the concentrations. Significantly positively correlations among NEOs (r = 0.135 to 0.661, p &lt; 0.05) suggested the exposure sources of NEOs are common or related. Significant sex related differences (ΣNEOs, IMI and THM, p &lt; 0.05) and region-specific differences in urinary NEOs concentrations were observed within China. Calculated daily intake of IMI on the basis of body weight indicated a low health risk from current level of exposure to IMI in China. Following exposure, NEOs get metabolized in human bodies. In comparison of NEOs, urinary NEOs metabolites (m-NEOs) were found as 4.95 to 37.7 times higher than their corresponding parent NEOs in the same sample set. The ratio of Σm-NEOs/ΣNEOs was significantly (p &lt; 0.01) higher in females than in males, suggesting unique exposures or metabolism in females. Therefore, the metabolites including N-desmethyl-acetamiprid (N-dm-ACE), 5-hydroxy-imidacloprid (5-OH-IMI), 1-methyl-3-(tetrahydro-3-furylmethyl) guanidine (DIN-G), and 1-methyl-3-(tetrahydro-3-furylmethyl) (DIN-U), should be considered in future biomonitoring and toxicity studies.

Urinary levels of neonicotinoid insecticides and their metabolites in China: The first baseline national survey and new recommendation for future biomonitoring study

ACS Spring Meeting 2021

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