Insecticide Residues in Eggplant Fruits, Soil, and Water in the Largest Eggplant-Producing Area in the Philippines

Abstract

This study looked into the insecticide residues in eggplant, soil, and water samples in the largest eggplant-producing community in the Philippines as well as to analyze the fate of insecticides. The study area consisted of eggplant farms in a community in the largest eggplant producer in the Philippines. A total of 20 of the environmental samples were taken from the farms and analyzed using gas chromatography. The samples were distributed spatially over a mean distance of 451 m (s.d. = 20.2 m). For eggplant pesticide application, the mean spraying time of the farmers was 1.4 (sdv = 0.53) h/day, 4.13 (sdv = 1.9) days/week, 3.79 (sdv = 0.22) weeks/month, and 1 year/cropping season. Forty percent of the farm samples of eggplants had positive reading of insecticides cypermethrin and chlorpyrifos between 0.02 and 0.03 mg/kg. There was no positive reading for the 20 water samples. There was only one positive reading of chlorpyrifos in one farm out of 20 soil samples at 0.03 mg/kg. Although Prevathon and Malathion were used by all the farms for eggplant pesticide application, the liter-years of exposure to pesticide was very low for both (0.06, 0.56). Although Brodan and Magnum were not prevalently used, they had the highest liter-years of exposure to pesticide at 4.73 for chlorpyrifos, and 6.09 for cypermethrin. The amount and duration of use of insecticide is important in the determination of its persistence in vegetables and in the environment. In this study, Brodan was the largest and longest used insecticide for eggplants which explains why there was reading for both cypermethrin and chlorpyrifos in the eggplants, but none for Malathion and chlorantraniliprole. The presence of insecticide in water, soil, and plants is also based on its environmental fate. Pesticide regulation and pesticide residue monitoring have been pursued to varying degrees of success in the Philippines, but implementation is considered inadequate. The study also suggests for better implementation of pesticide regulation.