Geochemical assessment of heavy metal impact on soil around Ewu-Elepe Dumpsite, Lagos State, Nigeria

119 Ife Journal of Science vol. 22, no. 3 (2020) INTRODUCTION Solid waste collection and disposal have always being a universal problem. However, developed countries have found a way around their solid waste management problems while developing countries are still battling with theirs (Arneth et al., 1989; Adewole, 2009; Ogunseiju, 2014). Waste is most of the time contained in landfills with impermeable bottom liner and leachate collection centers to prevent environmental pollution in the developed countries, while open dumps are the most common methods of waste disposal in developing countries of the world. The reason why the open dump systems of waste management are being operated in developing countries is due to technical, financial, complex and the expensive engineering system involved in setting up a sanitary landfill (Ogunseyiju, 2014). Large population and obsolete techniques used in waste management complicate the problem in developing country. Waste disposal in landfills is an integral part of waste management strategy around the world. The production of by-products of organic and inorganic decomposition known as leachates in landfills pose a serious threat if released to the environment (Arneth et al., 1989; Kjeldsen, 1993). Physical, chemical and microbial processes are usually involved in the release of pollutants from the wastes into the environment (Kimmel and Braids, 1974). Leachates when released into the underlying groundwater forms a contaminant plume that can alter the physical, chemical and microbial properties of groundwater (Baedecker and Back; 1979; Ogunseiju, 2014). The result of mass transfer processes of contaminants into the leaching water percolating through the waste layer is described as leachate pollutant. Solid waste and sewage generation and their poor disposal mechanism in urban areas of most developing countries have become an inherent threat to the environment. Open dumps are usually sited in reserved areas such as outskirts of towns far from residential areas, but with the upsurge in cities population as a result of ruralurban migration, these reserved areas are being https://dx.doi.org/10.4314/ijs.v22i3.10