Aquatic Environmental Contamination: The fate of Asejire Lake in South-Western Nigeria

Abstract

In Nigeria major cities face serious water pollution crises, in which lack of environmental control of water-dependent activities play an important part. This generates unpleasant implications for health and economic development since most urban and rural areas depend upon lakes and rivers for their water supplies. A study of catfish from Asejire Lake (located at the outskirt of Ibadan, a major city in Oyo State of South-West Nigeria) was carried out to assess the level of contamination due to effluents from various industries in Ibadan, Oyo State particularly the Nigerian Bottling Company, Plc (NBC). The industrial site is located close to the lake and is known to be passing effluent to it. Heavy metals analysis was carried out by the use of an atomic absorption spectrophotometer (AAS) using an airacetylene flame in the Alpha-4 ChemTech spectrophotometer. The result shows that Fe had the highest concentration (11.9 ppm), this was evidenced by an absorption peak at 406 nm and the high level of Fe after its AAS metal determination experiment. The other metals gave the following concentration: Ni (0.9 ppm), Mg (0.47 ppm), Mn (0.45 ppm), Zn (0.35 ppm), Ca (0.06 ppm), Cu and Co (0.00 ppm). These metals had a threshold in which the body can take before they will be lethal, as a result, accumulation and continuous consumption of these aquatics and drinking of the water can lead to coma or death. Fish stocks are at the upper end of the food chains and are vital food supplies to local populations and thus they present a major source of contaminants to local communities. Therefore this project highlights the need for environmental regulation and policy intervention in other to prevent the risk attached to accumulation of these contaminants via the water and the aquatic life. This paper focused on the instruments needed by the policy maker to be better informed and understand how to create a cleaner environment for people so as to increase the economy, health and well being of the people.

Key words: Asejire lake, pollution, contamination, catfish.