The Effects of Ferrous Sulphate Heptahydrate and Lead Nitrate On the Atterberg Limits and Consolidation Indices of Laterite

Abstract

Open dumping of wastes is a common practice in developing world. Leachates of varying chemical compositions including heavy metal are introduced into the soil from the dumped wastes. The adsorption of heavy metal ions and displacement of hydrogen ions in the soil may lead to changes in the geotechnical properties of the soil and affect the performance of the soil as foundation material. In this paper, the change in the Atterberg limits and consolidation indices of an artificially contaminated soil sample with iron and lead is presented. A selected soil sample was analysed in its uncontaminated state and the index and other geotechnical properties determined. The soil sample was contaminated with different concentrations of iron and lead and the soil samples were cured in separate sealed containers for 0, 28 and 72 days. The Atterberg limits and consolidation properties of the contaminated soil samples were determined using standard methods and compared to that of the uncontaminated soil. The results showed that the tested heavy metals have significant effect on the selected geotechnical properties of soil apart from posing only environmental threats with F=20.85; F_crit=3.48; p<0.05, (for iron contamination) and F=62.52, F_crit=3.48; p<0.05 (for lead contamination).