Organochlorine Residues in the Nigeria Environment: A Study on Residues in Adoka Rice Farm, Benue State

The use of pesticides containing organochlorine on farmlands is a means of improving agricultural yield, but analysis of pesticide residues is a way to determine the level of human exposure to these chemicals and hence their potential human health hazards. Increased use of pesticides results in contamination of the environment and the excess accumulation of pesticide residues in food products, which has always been a matter of serious concern. Soil samples were collected on the farm land to determine the concentration of organochlorine pesticides. Control samples were collected 5 km away where there was little or no application of organochlorine pesticides. Standard analytical methods were employed for the determination of some physicochemical parameters. Collected samples were analyzed for residues of organochlorine pesticides using GC - MS after careful extraction and cleanup. The results of the physicochemical analysis showed that the mean pH value of soil samples ranged from is 6.2 indicating slight acidity that were within WHO accepted limits. The mean total organic carbon (TOC) value is 14.57%, to while the mean cation exchange capacity (CEC) is 7.85 cmol/kg in soil. The mean Electrical conductivity carbonates content and moisture content also exhibit minimal significance in the soil. DDT was the only OCP detected in this analysis with average concentration of 10.5 mg/kg which is above the EU/WHO MRL of 0.05 mg/kg. Potential source analysis traced the occurrence of high residual levels of DDTs to historical applications. TOC was pointed as a significant variable controlling OCP distribution, and artificial influences possibly contributed to the fate of OCPs in the soils. The OCP contamination levels in the agricultural soils based on national standards are generally considered safe for crop production, but however, pose significant carcinogenic risks to exposed populations based on the calculated results of the ILCR parameters.