Residue determination and dietary risk assessment of mesotrione, nicosulfuron, atrazine and its four metabolites in maize in China

Abstract

IntroductionTo improve maize yield in China, multiple herbicides have been simultaneously applied to control more weeds. However, this combined application raises concerns about potential residues and their subsequent risks to human health. Therefore, evaluating the residues and dietary risk of new herbicide formulations is critical for the sustainability of maize production.MethodsUsing UHPLC-MS/MS, we developed quick methods for the determination of residues of mesotrione, nicosulfuron, atrazine and its four metabolites with acceptable accuracy and precision. The limits of quantification (LOQs) were 0.01 mg/kg for mesotrione and atrazine-desethyl-desopropyl, and 0.005 mg/kg for nicosulfuron, atrazine, 6-deisopropyl atrazine, 2 hydroxyatrazine, and deethylatrazine. Field trials were conducted at 12 different locations in China. And the risk quotient (RQ) model was used to evaluate the chronic risk of residues of these herbicides.ResultsThe residues of straw samples were in the ranges of <0.01 mg/kg for mesotrione, <0.005–0.010 mg/kg for nicosulfuron, and <0.037–0.254 mg/kg for accumulated atrazine. In green straw, the observed ranges were <0.01 mg/kg for mesotrione, <0.005–0.007 mg/kg for nicosulfuron, and <0.037–0.211 mg/kg for accumulated atrazine. Meanwhile, for both green and fully-grown maize, residues were <0.01 mg/kg for mesotrione, <0.005 mg/kg for nicosulfuron, and <0.037 mg/kg for accumulated atrazine. And all RQ values of green and fully-grown maize were below 100%.ConclusionBased on the RQ model, the dietary risk of exposure to three herbicides through maize was acceptable by consumers. This study helps guide the rational use of mesotrione, nicosulfuron and atrazine to ensure the safe production of maize and our human health.