Pollution Assessment with Respect to Five Heavy Metals in Urban Soils of the Greater Chennai Region, Southeast Coast of India

摘要

During the last few decades, contamination of air, water and soil has become the talk of the era due to high anthropogenic influence especially in the metropolitan cities. Taking this in mind, this study is taken place to identify the influence of anthropogenic activity by assessing pollution of selected heavy metals in an urbanized environment. Concentrations of five heavy metals (Cd, Pb, Zn, Cr, and Cu) in 155 urban soil samples collected from an area covering ca.595 km~2 across the Greater Chennai Region (GCR) at the coast of Bay of Bengal (Indian Ocean), with fourth highest population among metropolitan cities of India, helped to assess the level of pollution in superficial deposits. Their higher values in comparison with UCC, and more Cd in most of the samples from the northern part, could be from urban solid wastes that being dumped in various parts around the GCR. Enrichment factor (EF>40) and contamination factor (CF>6) were higher, and the ecological risk index (E_r) and global ecological risk index (RI) revealed considerable risk from Cd which might cause adverse health effects such as cardiovascular diseases and cancer. The higher impact of vehicular emissions shows positive correlation between Zn and Cu in the study area. Increase in Cd, Cu, Zn, and Cr compared to the similar study conducted about a decade ago suggested enhancement in unsegregated solid waste, vehicular activity, and small-and large-scale industries. Also, the reduction in leaded petrol usages might have decreased Pb content but the influence of thermal power plant continued to be dominant at northern GCR.In depth studies as well as proper waste disposal and treatment is needed to protect the environment from further contamination.