Identification and Quantification of Dimethachlon Degradation Products in Soils and Their Effects on Soil Enzyme Activities

Abstract

In this study, high-performance liquid chromatography−high-resolution mass spectrometry (HPLC−HRMS, Q-Exactive Orbitrap) and Compound Discoverer 3.3 were used to screen dimethachlon degradation products in soils. Four metabolites 4-(3,5-dichloroanilino)-4-oxobutanoic acid (DCBAA), 3,5-dichloroaniline (3,5-DCA), succinic acid, and muconic acid were confirmed by primary and secondary ion mass spectrometry comparisons between standards and samples. A quantitative analysis method of dimethachlon residues and four metabolites in soils was developed using HPLC−HRMS. Dimethachlon degradation in agricultural soil indoor unsterilized, sterilized, and field environments in three typical areas was measured. Dimethachlon degraded fast with a half-life of less than 1 day in three nonsterile soils. The maximum DCBAA and 3,5-DCA residues during degradation could reach 22.5−35.2% of the initial concentration of the parent dimethachlon. The metabolite DCBAA had a greater impact on soil enzyme activity than the parent dimethachlon.

Development of Simultaneous Determination Method of Pesticide High Toxic Metabolite 3,4-Dichloroaniline and 3,5 Dichloroaniline in Chives Using HPLC-MS/MS

“…Since both 3,4-DCA and 3,5-DCA have higher bioaccumulation levels and more toxic health risks in humans than their parent compounds [23,24], they may damage the endocrine system when entering into the human and animal bodies through the food chain. In the production of agricultural products (e.g., chives), the extensive use of phenylurea herbicides and dicarboximide fungicides results in high environmental risks owing to their hazardous nature of toxic residues.…”