Uptake, translocation and metabolism of acetamiprid and cyromazine by cowpea (Vigna unguiculata L.)

Abstract

Acetamiprid (ACE) and cyromazine (CYR) are the two pesticides that are used relatively frequently and in large quantities in cowpea growing areas in Hainan. The uptake, translocation and metabolic patterns and subcellular distribution of these two pesticides in cowpea are important factors affecting pesticide residues in cowpea and assessing the dietary safety of cowpea. In this study, we investigated the uptake, translocation, subcellular distribution, and metabolic pathway of ACE and CYR in cowpea under laboratory hydroponic conditions. The distribution trends of both ACE and CYR in cowpea plants were leaves > stems > roots. The distribution of both pesticides in subcellular tissues of cowpea was cell soluble fraction > cell wall > cell organelle, and both transport modes were passive. A multiplicity of metabolic reactions of both pesticides occurred in cowpea, including dealkylation, hydroxylation and methylation. The results of the dietary risk assessment indicate that ACE is safe for use in cowpeas, but CYR poses an acute dietary risk to infants and young children. This study provided a basis for insights into the transport and distribution of ACE and CYR in vegetables and contributes to the assessment of whether pesticide residues in vegetables could pose a potential threat to human health at high concentrations of pesticides in the environment.