EVALUATION OF INDUSTRIAL DISCHARGE POINT SOURCE POLLUTION IN IKEJA INDUSTRIAL ESTATE, IKEJA, LAGOS, NIGERIA

Abstract

 

The rate of water pollution resulting from industrial effluents is on the increase in Nigeria. This study assessed the physico-chemical and heavy metal parameters from waste water and sediment samples from drainage discharge point of brewery, textile, paints, confectionary, and fibre-cement roof industries in Ikeja Industrial Estate, Lagos in dry and wet seasons. The samples were evaluated for their quality and the data obtained were compared with local and international regulatory standards. Among the parameters determined were colour, pH, temperature, electrical conductivity, total dissolved solid, biological oxygen demand (BOD), chemical oxygen demand (COD), chloride, sulphate, and phosphates using standard methods and procedures. The levels of heavy metals in the water and sediment samples were determined using atomic absorption spectrophotometer (AAS). The values of pH, temperature, BOD, COD, and orthophosphate P in the water samples were higher than the NESREA limit.  Results of analysis of variance (ANOVA) revealed that there was no seasonal significance difference in water and sediment samples (p > 0.05) in all the sampling points. The concentrations of Cd, Cu, Pb, Cr, Zn and Ni in water and sediment samples were higher than the NESREA standards in one or two sampling points along the drainage system. This study revealed that some of these industries still discharge untreated or partially treated waste water into the environment through the drainage system. There is need for regular monitoring and compliance enforcement by appropriate Government Regulatory Agencies on regulatory requirements.