Multiple pesticide residues in rice and chlorpyrifos persistence in peat soils

Pesticide contamination in food crops and agricultural soils poses a significant risk to food safety and environmental health. This study examined pesticide residues in rice cultivated on peat soils and investigated the persistence of chlorpyrifos in those soils. A total of 41 rice samples from peatland paddy fields were analyzed using GC-MS/MS and LC-MS/MS, revealing 19 different pesticide active ingredients. Propiconazole (71 %), azoxystrobin (56 %), and chlorpyrifos (49 %) were the most frequently detected compounds, with several residues exceeding maximum residue limits (MRLs). To explore the potential soil-to-plant transfer, 16 peat soil samples were analyzed specifically for chlorpyrifos. Despite discontinued use for over a year, chlorpyrifos was still detected above 0.01 mg/kg in 50 % of the soils. These results suggest that peat soils—with their high organic matter content and anaerobic conditions—can prolong chlorpyrifos persistence, potentially contributing to residual contamination in rice. The findings support the need for stricter pesticide monitoring, targeted soil assessments, and adoption of integrated pest management (IPM) practices to reduce health and ecological risks in peatland-based agriculture.