Assessment of Organochlorine Pesticide (OCP) residues in water, sediments and fish from Bonny Estuary, Nigeria

Abstract

Organochlorine pesticide (OCP) residues from water, sediment and fish in Bonny estuary were assessed quarterly from 2016 to 2017 to ascertain their concentrations in the matrices with respect to the regulatory limit by Nigeria legislation. Surface water samples were obtained directly from three locations using cleaned 1.5litres plastic vessels, while Sediment samples were collected at 10cm depth using triple sediment corer. Fish specimens: Tilapia, mullet and shrimps were obtained from fishers during the field trip. OCP in the samples were determined, using Gas Chromatography-Mass Spectrometry (GC-MS). The OCP concentration in sediment ranged from 0.7ppm (2016) to 0.59ppm (2017), biota (16ppm-Tilapia sp.,17ppm-Mullet, and 14ppm-Shrimps), and water(>10ug/l) Five pesticide residues; DDE, DDT, endosulfan sulphate, sulfan 1, endrin aldehyde occurred commonly in all the three biota. The result indicated a percentage increase in concentration of 10.3% (Tilapia), 44.5% (Mullet), and 94.06% decrease (Shrimps) from 2016 to 2017.

Keywords: Organochlorine pesticides (OCP), Bonny estuary, Persistent organic pollutants (POP)