Neonicotinoids and their metabolites in vegetables and fruits in Shenzhen: Human exposure and health risks

Neonicotinoids (NEOs) are widely present in vegetables and fruits, and their metabolic processes result in the presence of metabolites (m-NEOs) in vegetables and fruits as well. The toxicity of m-NEOs to the human body is comparable to or even greater than of the parent neonicotinoids (p-NEOs). However, research on m-NEOs in vegetables and fruits remains limited. Herein, we analyzed 8 NEOs and 7 m-NEOs in 490 vegetable samples and 149 fruit samples gathered from Shenzhen, China. Then we calculated the estimated daily intake (EDI), as well as the hazard quotient (HQ) and hazard index (HI) for both children and adults in order to evaluate the potential health risks. Thiamethoxam (THM) and imidacloprid (IMI) were the most frequently detected NEOs in vegetables (70.6 %) and fruits (68.5 %), respectively, with THM exhibiting the highest average concentration (37.52 μg/kg) in vegetables and clothianidin (CLO) showing the highest average concentration (9.55 μg/kg) in fruits. Further analysis revealed that the concentrations of m-NEOs in vegetables and fruits were lower than those of NEOs. However, significant positive correlations (P < 0.05) were observed between m-NEOs and their respective p-NEOs, probably as a result of the conversion of p-NEOs through metabolism in both vegetables and fruits. Cumulative risk assessment indicated that the median HI values for both children and adults were generally below the safety threshold (4.92 × 10−4 to 3.02 × 10−3), but maximum HI values associated with vegetable consumption exceeded the acceptable daily intake for both children and adults. While the HI values in vegetables and fruits mainly primarily stemmed from NEOs, the potential health risks posed by m-NEOs warrant ongoing assessment.