To improve the efficiency of electrokinetic remediation of contaminated soil, by introducing single pollutant cadmium and setting up a self-made device test, electrokinetic remediation technology was applied to artificially simulated contaminated soil to explore the influence of three different two-dimensional electrode arrangements [triangle (2-e-1), rectangle (2-e-2) and hexagon (2-e-3)] on electrokinetic remediation of cadmium contaminated soil in this paper. The cathode of the test device was made of high purity (99.9%) graphite electrode, and the anode was made of stainless steel electrode. Under the condition that the voltage gradient, electrode material, electrolyte and electrification time of the three groups of tests were consistent, the current change, pH value, conductivity, total cadmium content and cadmium morphology of the three groups of tests were compared. The experimental results showed that the triangle (2-e-1) group, the current increased slowly during the process of power on, the pH value of soil was over acid, and the transformation rate of various forms of cadmium contained in the soil after the restoration was low. The current change rate of the rectangular (2-e-2) electrode arrangement was the highest, the soil environment was super alkaline, and the removal rate of cadmium was an average level. The hexagonal electrode arrangement (2-e-3) led a large current drop rate and a weakly alkaline pH environment, the removal efficiency of cadmium at sampling points (S1 and S2) near the anode was as high as 95.54%, and the comprehensive removal rate of cadmium at each sampling point reached 89.6%, moreover, the pollutant removal was uniform and efficient.

Soil pollution is a worldwide problem caused by both natural and anthropogenic activities. This has resulted in health and physiological problems to both plants and animals. This study investigated heavy metals in soils within the immediate vicinity. Soils from Seven APIIC zones in Visakhapatnam were collected and analysed for physicochemical characteristics and heavy metals. The data obtained were subjected to the pollution index model and multivariate statistical analysis. The data obtained showed that the soils are rich in zinc, and heavy metals are above trace level with a minor positively skewed distribution. The analysis of pollution index, geoaccumulation index and ecological risk factors in soils in all the locations showed that they are mainly contaminated and polluted by Cd followed by Zn. The mean heavy metal concentrations around APIIC can be arranged in increasing order as Cr < Co < Pb < Cu < Cd < Zn. Element pairs such as Zn-Pb, Zn-Cu, Zn-Cd, Pb-Cu, Pb-Cd, Cu-Cr, Cd-Co and Cr-Co showed strong positive correlation coefficient “r” indicating their association in the study area. The observed concentrations of heavy metals revealed that soil contamination has been increasing and measures must be taken to ensure the adoption of more environment-friendly practices.

In this project, the study of soil characteristics due to the municipal solid waste was carried out in a selected location around the recently closed Municipal Solid Waste (MSW) dumpsite located opposite to Periya Eri in Chromepet, Chennai. Soil samples were collected from the selected location, i.e. 2 sites within 1500m from the dumpsite and another 2 sites beyond 1500m from the dump yard. Total 12 soil samples from 4 sites were collected from a ground depth of 0-30cm, 30-60cm and 60-90cm below the surface. The collected soil samples have been analyzed for pH, moisture, total organic matter, ash content, total organic carbon, specific gravity, conductivity and bulk density and the result were compared with the standards. The study suggested, providing Permeable Reactive Barriers (PRBs) around the solid waste dump site/landfill for reducing the leachate concentration before entering to the soil and thus soil contamination can be minimized to some extent and this technology is cost-effective and eco-friendly since the materials used in the barriers are locally available and low-cost which is sustainable and protect human health, nature and the environment. This study indicated that soil properties did not reach high pollution levels, and therefore posed a low eco-risk potential in surface soil near the landfill.