Impact of Rare Earth Mining and Processing on Soil and Water Environment at Chavara, Kollam, Kerala: A case study

摘要

The mining and processing of rare earth minerals along the coastline of Chavara, Kollam, Kerala has been a significant step in self reliance for the country in terms of being a strategically important industry but at the same time the grave enviromental consequences because of the improper manangenent of the industrial waste from the titanium dioxide (TiO_2) pigment producing industry is a cause of concern. This has led to the geo-environmental degradation of surrounding area which is also a high background radiation area. This study attempts to compare the geochemical variation in the soil due to contamination and the extent of water pollution from different water sources in the study area. Analysis of the surface soil (0-30cm) from contaminated land and inhabited land (supposedly less contaminated) provide a measure of the total concentrations of the elements present in the soil. XRF results indicate the increase in the concentrations of toxic heavy metals (e.g. Fe, Cr, V, Ni, Cu, Zn, Pb, Sr etc.) while concentrations of essential elements (e.g. K, Ca, Si, Ti, Zr) decreased due to contamination. Elements Mg, Ag, Au, Hf, Te, Nd, Yb, Ga present in inhabited area soil were found to be absent in contaminated soil. Co, Sn, W, Se, Br, Sm, Tb, Dy were detected only in contaminated soil. SEM analysis of the soil from residential area showed distinct mineral assemblage and that of contaminated soil, the signs of chemical weathering . The observed health problems in the local area indicate urgent need for health risk assessment and subsequent remediation of contaminated soil.