Pollution Load of Heavy Metals in Ilupeju, Ikeja and Isolo Industrial Wastewaters and Seasonal Impacts on Quality of Water Downstream and Upstream in Lagos Metropolis

International Journal of Environmental Pollution and Environmental Modelling, Vol. 3(2): 73-82 (2020) (Original Paper) Pollution Load of Heavy Metals in Ilupeju, Ikeja and Isolo Industrial Wastewaters and Seasonal Impacts on Quality of Water Downstream and Upstream in Lagos Metropolis Daniel Gbadesere Akintunde 1*, Olukayode Bamgbose 2 1 Department of Chemistry, Federal College of Education (Technical) Akoka Lagos, Lagos State, Nigeria. Department of Environmental Management and Toxicology, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria. 2 E-Mail: , Received 24.02.2020; Accepted 25.06.2020 Abstract: Profiles of heavy metals in Ilupeju, Ikeja and Isolo industrial wastewaters and seasonal impacts on quality of water downstream and upstream in Lagos metropolis were determined. Wastewater samples from industrial estate were collected at the point of discharge of effluents into the streams and at spatial interval of 50 to 200 meters upstream and downstream of the discharge point over a two- year period (2005-2007) .The effluents were analyzed for heavy metals using standard methods. At the point of wastewater discharge into water bodies, during dry and rainy seasons, only Manganese showed significant difference (p < 0.05) in the first year in Ikeja. In dry and rainy seasons, the level of iron fluctuated from 8.95 ± 0.18 mg/L upstream to 8.96 ± 0.88 mg/L downstream in Ikeja; 1.40 ± 0.17 mg/L to 15.94 ± 1.56 mg/L in Ilupeju and 9.10 ± 0.64 mg/L to 4.98 ± 0.76 mg/L in Isolo industrial zones. In all the industrial areas considered, all the heavy metals have high accumulation factor at one season or the other except chromium and zinc. Accumulation factor for manganese increases in order of 2.38<4.10<4.70 in Ilupeju, Ikeja, Isolo respectively and in the order of 2.21<3.91<4.04 for copper in Isolo, Ilupeju, Ikeja respectively. However, iron had highest accumulation factor of 11.38 in the rainy season for Ilupeju. The upstream and downstream levels of chromium, manganese, iron and lead were higher than permissible level with traces of cadmium. The upstream and downstream water quality was poor and not suitable for drinking and routine purposes hence control of industrial wastewater is necessary to asswage its impact on proximate river bodies. Key words: industrial wastewaters, effluents, discharge point, upstream, downstream, accumulation factor, heavy metals, seasonal variation. INTRODUCTION Occurrence of heavy metals in waters and biota usually indicate the presence of natural and anthropogenic sources [1]. The major natural sources of metals in waters occurs when rocks and soils are directly exposed to surface water resulting in chemical weathering of minerals and soil leaching [2]. The anthropogenic sources are associated mainly with industrial and domestic effluents, urban storm, water runoff, landfill leachate [3-4]. Heavy metals are found in significant quantities particularly in effluents from printing, pulp and paper, metal manufacturing, paints and pigment and mining industries [2, 5]. The discharge of various treated and untreated liquid wastes from these industries into water bodies account for large amount of metals in the rivers and lakes. The existence of heavy metals in aquatic environments has led to serious concerns about their influence on plant and animal life. Some metals such as copper, zinc and iron are biochemically classified as essential elements. Their presence in trace amounts play an important role in different physiological processes of living organisms. One the other hand, other elements such as lead and cadmium are non-essential to the body. The exhibit extreme toxicity even at trace levels [6-7]. The need to prevent their accumulation should therefore be given utmost priority. All heavy metals exist in surface waters in particulate, colloidal and dissolved phases. Rivers are a dominant pathway for metals transport and this was the reason trace metals were regarded as significant pollutants of even some small riverine systems [8-11]. Extent of mixing with water current, dilution factor, direction of water flow, synergistic effect of heavy metals and rapid industrialization are known factors that contributed to high levels of metal in water [12-13].The aggravated levels of metals in industrial wastes * Corresponding E-mail: This study is a part of Ph.D Thesis. 73 International Journal of Environmental Pollution and Environmental Modelling, Vol. 3(2): 73-82 (2020) are often toxic and could persist in the environment for a long time because of slow degradation thus causing hazards to human health, living organisms and ecosystem [14]. In Lagos with teeming population and diverse industrialization, levels of heavy metals in industrial wastewaters can be affected by seasonal changes. This study thus determines the impact of industrial wastewaters on upstream and downstream water quality as season changes. The choice of these three industrial areas was necessary by reason of size and diversity of industries releasing copious wastewaters into proximate streams thus causing changes in water quality. Regular assessment is necessary to check uncontrolled release from the industries and assess the performance of regulatory and supervisory bodies. STUDY AREAS The study was conucted in three major industrial areas in Lagos city namely: Ikeja, Ilupeju and Isolo industrial areas (Figures 1-3). Ikeja is located 30km North of Lagos Island and spans a total area of 325sqkm, bounded on the North, South, West and East by Agege / Ifako Ijaiye; Oshodi/Isolo; Alimosho respectively [15]. The major industrial sectors ranges from pharmaceutical, food and beverages, pulp and paper, textiles, dyeing, chemical to electrical appliances. All the wastewaters discharged from different industries in the area are connected by a network of canals and sewers and channeled directly into Iya Alaro River. The river meets Shasha River at the Northern part of Lagos and flows to join Aromire River in the vicinity of Nigerian Bottling Company along WEMABOD site. The downward flow creeps through Oregun and Ojota and finally empties into Lagoon (Figure 1). In- between Oregun and Ojota, along Access Road, the water is being used by dwellers for washing and fishing purposes. Ilupeju is located 10km North of Lagos City Core. The key processing industrial sectors include engineering products, cosmetics, foods and beverages ,plastics, printing and textile industries [16].The sewers carrying the effluents pass through Oshodi/Anthony expressway and channeled into Arowojobe River until it eventually empties into the Lagoon (Figure 2). Isolo is located 10 km North of Lagos City. It is bounded on the North, South, East and West by Ikeja, Mushin,Oshodi and Okota respectively. The major industrial sectors include textiles, plastic, clothing, beverages, leather, steel and aluminium. The processing industries have their effluents discharged into Osolo River which flows from Fatai (...truncated)