ASSESSMENT OF PHYSICO-CHEMICAL CHARACTERISTICS OF LEACHATE CONTAMINATED LATERITIC SOIL

Abstract

This research studied the physico-chemical characteristics of leachate contaminated soil. Leachate is known as an important source of environmental pollution, more especially groundwater, pollution due to the presence of organic and inorganic substances, including heavy metals. Leachate is a major problem for municipal solid waste landfills and causes significant threat to surface water and groundwater. Leachate is generated by excess rainwater passing through the waste body. The pollutants from the waste material are transferred to the percolating water by the combination of physical, chemical and microbial processes. Leachate is characterized as water-based solution of four groups of pollutants; dissolved organic matter, heavy metals, inorganic macro components, and xenobiotic organic compounds. The physio and bio-chemical analysis: BOD, COD, pH, EC, total hardness, nitrite, chloride, calcium and heavy metals such as Pb, Fe, Zn, and Cu were determined. From the results obtained, pH increases with increase in percentage contamination, from pH of 5 at 0% contamination to 5.62 at 100% contamination and cation exchange capacity also increased from an initial value of 187.613mg/l at 0% to 200.575mg/l at 100% contamination. These results show that the dumpsite has slight effects on the adjacent stream and underlying soil. Therefore, the implementation of a properly designed leachate collection system to prevent future risk of continuous contamination of the underlying soil and groundwater is important.