Organophosphate pesticide residues in surface water and bilih fish (Mystacoleucus padangensis Blkr.) in Lake Singkarak, West Sumatra

Abstract

Organophosphate pesticide is a pesticide derivate that is used widely by farmers because it has a high killing power against insects and easily disappears from plants. Organophosphate pesticide residues can accumulate in the environment and also cause acute and chronic poisoning in humans. Singkarak Lake in West Sumatra Province is surrounded by many agricultural and farming areas. One of fisheries resources that can be affected by activities at those areas is Bilih fish (Mystacoleucus padangensis). The study aims to determine the levels of organophosphate pesticide residues in Singkarak Lake’s water and Bilih fish. Seven organophosphate pesticide compounds: Diazinon, Fenitrothion, Methidathion, Malathion, Chlorpyrifos, Parathion, and Profenofos were analyzed. In June 2021, surface water and Bilih fish samples were collected from 10 sampling locations in Singkarak Lake. The organophosphate pesticide in the samples was determined using gas chromatography. The results showed that residues were detected in water samples of four locations (Ombilin, Tikalak, Sumani, and Paninggahan), but not in the other six locations (Batu Taba, Sumpur, Guguak Malalo, Saniang Baka, Muaro Pingai, and Tanjung Mutuih) as well as below 1 ppb. Methidathion, Malathion, Chlorpyrifos, and Parathion were detected in lake water at range 2 to 8 ppb. Except for the Bilih fish sample from Ombilin, the majority of the samples contained organophosphate residues. Diazinon, Fenitrothion, Methidathion, Chlorpyrifos, Parathion, and Profenofos were the organophosphate derivate found in the fish samples. Malathion compound was not found. The organophosphate residue concentration in Bilih fish ranged from 2 to 70 ppb.