Abstract

The wide use and application of Organochlorine pesticides (OCPs) is a menace to non-target aquatic biota. The study evaluated the levels of OCPs residues in Tympanotonus fuscatus and sediment within three (3) selected areas of the Lagos Lagoon, Nigeria using Gas Chromatography coupled with Electron Capture Detector (GC-ECD). The mean concentration of OCP residues detected in T. fuscatus and sediments were Lindane, Diedrin, Aldrin, Endosulfan (isomers alpha and beta endosulfan), and DDT (isomers orthopara and para-para DDT). Generally, the total OCP concentration was higher in T. fuscatus than in sediments while stations 1 had the highest concentration of ∑ OCPs in both tissue and sediment samples followed by stations 2 and 3. Endosulfan concentration was the highest followed by Dieldrin > DDT > HCH > Lindane in decending order. In sediment, the mean concentration of Lindane ranged from Not Detected (ND) to 342.0 ng g-1 while HCH ranged from 262 - 818 ng g-1. Total Endosulfan ranged from 776 – 4849 ng g-1 while DDT ranged from 349 – 2211ng g-1. Bioaccumulation Factor (BAF) values in descending order was as follows: Endosulfan > Beta _BHC > Endrin aldehyde with the highest BAF values recorded from Iddo (3). Additionally, concentrations of Dieldrin > Heptachlor > DDT were recorded in descending order at Unilag Lagoon front that exceeded the FEPA and USEPA Limit (BAF > 1); an indication that harmful effects are likely for aquatic species. Thus warrants proper and consistent monitoring of OCPs in the Lagos Lagoon.