Study of Organochlorine Pesticide Residues Analysis in Water, Fish and Sediment using GC-ECD in River Loko, Nasarawa State, Nigeria

Abstract

Levels of organochlorine pesticide (OCPs) residues in sediment, water and fish in River Loko, Nasarawa State, Nigeria, were evaluated for possible pollution of the aquatic system. Water and sediment samples were collected from the river at 3 locations. Fish caught in the river were bought from fishermen at the bank of the river. The samples were collected in rainy season and preserved according to standard methods. Liquid-liquid extractions of samples were carried out, and then quantified using gas chromatography coupled with electron capture detector (GC-ECD). The OCPs levels ranged from 0.06 to 1.53 µɡ/Kɡ in sediment, 0.03 to 1.34 µɡ/Kɡ in water and 0.02 to 1.34 µɡ/Kɡ in fish.  2, 4-Dichlorophenoxacetic acid (2,4-D) was the most accumulated OCP in sediment (1.64±0.10 µɡ/Kɡ), water (1.34±0.08 µɡ/Kɡ), and fish (1.34 µɡ/Kɡ). Concentrations of OCPs generally varied in the order of sediment > water > water ~ fish.  ANOVA shows that concentrations of OCPs in water and fish  were significantly (p ≤ 0.05) lower compared to sediment, except for mecoprop, imidacloprid, 2,4-D, and aldrin, which were not significantly different in the samples. Pearson correlation matrix for OCPs in water and sediment show moderate to very strong and positive correlations except for mecoprop (-0.705), alachlor (-0.217), imidacloprid (-0.082), permethrin (-0.339) and aldrin (-0.795).Concentrations of OCPs were within the FAO/WHO acceptable limits except for aldrin, mecoprop, metolachlor, simazine, DDT and dieldrin. Regular monitoring of the quality of River Loko becomes necessary due to accumulation of OCPs.