Five pesticides were detected in watermelons, namely carbofuran, chlorpyrifos, diazinon, dimethoate, and metalaxyl, while only three were found in durian samples, namely dichlorvos, dimethoate, and metalaxyl. Pesticide residues were detected in approximately 90 % of both the watermelon and durian samples tested. The results found in the present study indicate that pesticides are commonly used in the cultivation of watermelons and durians in Thailand. Dimethoate and metalaxyl appeared to be the most often used pesticides for these fruits’ cultivation. The mean level of dimethoate found in watermelons was 0.7 ppb, which was only 3.5 % of its recommended MRL.
The mean level of metalaxyl detected in watermelon samples was 7.1 ppb, which was approximately only 3.5 % of the recommended MRL of metalaxyl. This finding implies extremely low levels of pesticide contamination in the watermelons sold in Thailand.