Assessment of ameliorative effects of organic dietary interventions on neonicotinoid exposure rates in a Japanese population

Abstract

Neonicotinoid insecticides (NNIs) are a popular class of insecticides used in various pest management regimens worldwide. Biomonitoring studies continuously report high exposure rates of NNIs in various human populations across the globe. Yet, there is no validated countermeasure for combating the recent exponential rise in NNI exposure rates observed in human populations. The current study assessed the impacts of organic dietary interventions on NNI exposure rates in a Japanese population. A total of 103 volunteers were recruited into the study. Subjects were either served with Organic diets for 5 and 30 days or conventional diets. A total of 919 repeated urine samples were collected from the participants and then subjected to LC-MS/MS analysis to determine urinary concentrations of 7 NNIs parent compounds and an NNI metabolite. Eight NNIs were detected; with a decreasing detection frequency (%Dfs) pattern; desmethyl-acetamiprid (dm-ACE) (64.96%) > dinotefuran (52.12%), imidacloprid (39.61%) > clothianidin (33.95%) > thiamethoxam (28.51%) > acetamiprid (12.62%) > nitenpyram (5.33%) > thiacloprid (2.83%). Dinotefuran, dm-ACE, and clothianidin recorded the highest concentrations in the subjects. The %Df of NNIs in the 5-days or 30-days organic diet group were lower than those of the conventional diet consumers. The organic diet group showed lower rates of multiple NNI exposures than those of the conventional diet consumers. The mean and median cumulative levels of NNIs (median IMI_eq) were significantly lower in the organic diet group than the conventional diet group (p < 0.0001). The estimated daily intakes (EDIs) of NNIs were higher in adults than children, but less than 1% of NNI cRfDs, except for clothianidin, which exhibited a %cRfD of 1.32 in children. Compared to the conventional diet group, the 5- and 30-day organic dietary intervention showed drastic reductions in NNI EDIs. Findings from the present study give credence to organic dietary interventions as potential ameliorative strategies for NNI exposure rates in human populations.

Keywords: Conventional diet; Estimated daily intakes (EDI); Health risk assessment; Neonicotinoid insecticide; Organic diet; Relative potency factor (RPF).