Effects of Adding MSW Compost, Lime and Commercial Soil Improvers on Soil Heavy Metal Concentrations

Abstract

In this study, it was aimed to improve the soil with low pH and high amount of heavy metals by using municipal solid waste compost, lime and commercial soil improvers (Terra B and Viro Bind). In this study, the forms of the metals in the soil were determined by using sequential extraction method. It was investigated how soil improvers added to soil change the forms of metals. It was also investigated how the addition of soil improvers (compost, lime and commercial soil improvers) to the soil affects the amount of metal deposited on the roots and stems of the plants (Zea mays). It has been observed that the improvers added to the soil increase the pH value of the soil as T50 > Compost > Lime > A2. The sequential extraction results revealed that exchangeable forms of the studied heavy metals were transformed into the organically bound form. When compared with the control, high concentrations of the metals (except Ni) were found in the Organic Matter (OM) bound and residual forms following the addition of commercial soil conditioners such as A2 and T50, respectively. For the metals measured in the study, with the addition of A2, 96% of Pb, 99% of Cu and Cd, 86% of Ni and 97% of Zn are transformed into OM bound and residual forms, and with the addition of T50, 80% of Pb, 99% of Cu, Cd and ZN, and 78% of Ni were converted to OM bound and residual forms. These results indicated that the application of 1.5% lime combined with 10% compost substantially enhanced plant growth in the contaminated soils.