Effects of waste dumpsites on geotechnical properties of the underlying soils in wet season

Abstract

Indiscriminate disposal of waste and citation of open dumpsites are some of the key factors affecting the various soil geotechnical properties. Atterberg limit and consolidation tests were conducted to determine the effects of two open waste dumpsites (Uselu Market and New Benin) on geotechnical properties of their underlying soils. Soil sample collected from Uselu Market dumpsite in Benin City metropolis showed slightly lower hydraulic conductivity (K) of 1.0 10 -6 with plasticity index of 18.53% compared to sample collected 1.6 m from the same dumpsite which had high K value of 2.42 10 -3 with plasticity index of 6.9%. Soil sample collected from New Benin dumpsite in Benin City metropolis showed slightly lower K of 1.45 10 -6 with plasticity index of 13.8% than sample collected 1.6 m from the same dumpsite which had high K value of 2.14 10 -2 with plasticity index of 6.0%. X-ray florescent analyser (X-MET 7000) and direct soil pH meter were used to determine the composition of the aforementioned soil samples. The result of samples collected from both dumpsites indicated a low hydraulic conductivity compared to samples collected 1.6 m from both dumpsites. Also, the chemical composition and pH of both dumpsite underlying soils indicated high level of soil contaminants with pH of 3.3 and 3.5 which is very acidic unlike pH of other samples which were in the neutral range (6.8-7.1). Hence, a liner is recommended for all dumpsites or engineered landfill systems to mitigate against the challenges associated with open waste dumping system in the environment.