Determination of emamectin benzoate residues in topsoil and surface water of crop production areas in Thailand

Abstract

Emamectin benzoate (EB1), one of the most heavily imported agrochemicals in Thailand, ranks among the top three pesticides by import volume and expense. This study quantified EB1 residues in soil and surface water from 70 farms that applied EB1 during the 2022 rice and corn growing seasons. Samples were collected after the harvest season and analysed using high-performance liquid chromatography with ultraviolet detection at 254 nm. EB1 was detected in 97% of soil samples, with a mean concentration of 1.41 mg/kg (range: 0.05–8.82 mg/kg, standard deviation: 0.59 mg/kg). Water samples had a lower limit of qualification of 1 mg/kg, and limit of detection of 0.33 mg/kg. However, the study was limited to agricultural areas within the Nikompatthana subdistrict, Bang-Rakam district, Phitsanulok, Thailand. To broaden the research scope and possibly the generalizability of the data, future studies should expand sampling to other farms in different regions of Thailand to assess the spatial variability of EB1 contamination. Furthermore, a longitudinal study monitoring EB1 residues in soil and water over multiple growing seasons is necessary to understand the persistence and degradation of this pesticide in the environment. A comprehensive assessment of human health and the ecological risks associated with EB1 exposure should also be conducted. Additionally, strengthening regulations, raising public awareness regarding the potential risks of pesticide use, and promoting sustainable agricultural practices are crucial steps in mitigating the adverse effects of EB1.