Toxicología ambiental y analítica

Environmental Impact of Abattoir Waste Discharge on the Quality of Surface Water and Ground Water in Abeokuta

Abstract

Ojekunle OZ and Lateef ST

The problem of getting quality water is increasing as untreated effluents are discharged into water bodies. The study aims at assessing the impact of various abattoirs wastewater on ground and surface water bodies in Abeokuta. Water samples were collected randomly in 9 different locations of Abeokuta (4 stream and 3 groundwater samples as well and 2 around abattoir vicinity as controls of surface and groundwater). All the samples were collected on the same day in the morning and were analysed for physical, chemical and microbiological load. The water quality parameters measured includes; Colour, Odour, pH, EC, Temperature, TDS, Cl2, DO, BOD, COD, TS, TSS, NO3, PO4, Heavy Metals (Pb, Zn, Cu, Cd, Fe), microbiological analysis. The parameters were analysed using standard procedures and the results were analysed using descriptive and inferential statistics. The ranges of the means values of all the parameters measured for pH, Temperature, Hardness, TDS, Cl2, NO3, PO4, BOD5, DO, COD, TS and TSS were 7.23-7.36, 27.3°C-28.0°C, 164- 323 mg/L, 102-518 mg/L, 20-70 mg/L, 0.005-0.706 mg/L, 0.212-0.850 mg/L, 0.570-7.400 mg/L, 1.0-6.8 mg/L, 72-504 mg/L, 0.260-0.520 mg/L, 15.4-16.1 mg/L and that of heavy metal were; 0.03-0.19 mg/L, 0.020-0.090 mg/L, 0.010-0.030 mg/L, 0.0-0.700 mg/L, 0.040-4.960 mg/L for Pb, Zn, Cu, Cd, Fe respectively while that of the Faecal Coliform was 100- 300 cfu/ml respectively. The results of the study revealed that all of the measured parameters show significant difference in their mean except Cl2, EC, PO4 TDS and Temperature. From the results, it was discovered that the concentration of Hardness, Pb, Cu, Pb, Zn, Cd, Fe and Faecal Coliform exceeded the permissible limits of both the WHO and FEPA standard for drinking and wastewater effluent. Pollution of ground and surface water through discharge of waste is an evidenced by the high concentrations of pollution indicators, nutrients and trace metals above the acceptable limits.