Water quality changes due to abattoir effluent: A case on Mchesa Stream in Blantyre, Malawi

Abstract

Abattoir effluent is known to degrade the quality of receiving water bodies. This study assesses the impact of effluent from Shire Valley Abattoir on the physico-chemical parameters of Mchesa Stream in Blantyre. Water samples were collected from five sampling sites along Mchesa Stream located at progressive distances from the discharge point. Sampling was done three times over a period of four months (June to September 2008). The physico-chemical parameters tested were: pH, biochemical oxygen demand (BOD), dissolved oxygen (DO), suspended solids (SS) and electrical conductivity (EC). The mean values of the measured parameters were as follows: BOD (381.1 mg L^-1); DO (3.6 mg L^-1); SS (312.8 mg L^-1); pH (7.6); and EC (105.6 μs cm^-1). The highest concentrations of BOD and SS were 612.3 mg L^-1 and 477.3 mg L^-1 respectively and were obtained at a point of effluent discharge into Mchesa stream. One-way ANOVA showed significant deviation from WHO standards for BOD, SS and DO (p < 0.05). This study shows that effluents from the Shire Valley Abattoir have partially contributed to the pollution of Mchesa Stream to levels which pose health and environmental hazards to the surrounding communities.

Key words: Abattoir, effluent, water quality, physico-chemical parameters, Mchesa stream, hazard.