A Study of the Photodegradation Carbofuran and its Metabolites in Paddy Water Samples

Abstract

Rice fields are one of the agricultural sectors in Malaysia that are heavily pesticide-treated. This study aimed to determine how carbofuran degrades in paddy water and how carbofuran metabolites such as carbofuran-phenol and 3-keto carbofuran reacted during the degradation. The experiment was conducted in two distinct conditions: the first water sample was exposed to sunlight, while the second water sample remained in the dark. During the 56 days of observation, the study discovered carbofuran decomposed slowly in both conditions. The water sample exposed to sunlight showed a faster degradation rate (0.04/day carbofuran) than the water kept in the dark (0.0186/day). The results also demonstrated that photolysis and hydrolysis enhanced the carbofuran degradation in the water. Both 3-keto carbofuran and carbofuran-phenol were detected as metabolites with low concentration levels, ranging from 0.03±0.301 to 0.23±0.142 ppm. These metabolites are considered 'emerging pollutants' as they can be detected in the environment and may post-treat as much as the parent compounds themselves. Hence, this study is trying to fill the research gap to assess the route and rate of carbofuran and its transformation products.