Impact of Abattoir Effluent on the Physico-Chemical Parameters of Gbagi Stream (Odo-Eran), Ibadan, Nigeria

Abstract

The qualities of surface water bodies are being negatively impacted as untreated effluents are discharged into them through various sources. The effect of abattoir effluent on the physicochemical parameters of Gbagi stream, Ibadan, Nigeria was carried out bimonthly from March 2008 to January 2010. The physico-chemical qualities of water along the upstream and downstream sections of the river course were determined using standard methods. The results of the physicochemical parameters investigated were as follows: pH, 6.2-8.20; dissolved oxygen, below detection limit–4.67 mg/L; biochemical oxygen demand, 23.25–141.21 mg/L; chemical oxygen demand, 132.81–540 mg/L; chloride, 24.53–94.16 mg/L; phosphate, below detection limit–383.67 mg/L; sulphate, 100.00–2731.25 mg/L; lead, below detection limit–0.6355 mg/L; copper, below detection limit–0.4386 mg/L; iron, below detection limit–18.21 mg/L; zinc, below detection limit–18.9510 mg/L; nickel, below detection limit–0.2389 mg/L and cadmium,  below detection limit–0.0910 mg/L. Compared to the limits set by National Environmental Standards and Regulatory Enforcement Agency (NESREA) in Nigeria, the mean values of physicochemical parameters  were significantly higher (p<0.05) than the recommended limits set for effluent discharged into surface water bodies, except for pH that fell within the limits and dissolved oxygen that was lower than the limits. The need for treatment and monitoring of abattoir effluent before being discharged into water bodies and stringent enforcement of laws are recommended.