Zeitschrift für Geologie und Geophysik
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Comprehensive Assessment of Heavy Metals in Soils

Satyendra Nath Chakrabartty*

Assessment of Heavy Metal (HM) pollution of soil could be index based or model driven. Each suffers from methodological limitations. Classification of regions with respect to different indices gave different results. The paper suggests an assumption-free method to get comprehensive index as geometric mean of chosen indices to reflect overall pollution status of HMs in soil as a Composite Index (CI), avoiding selection of weights and scaling.

The proposed aggregation is applicable for all types of indices including those having skewed distributions and can be applied even for data with small sample size. With reduced level of substitutability among component indices, the method facilitates formation of chain indices, satisfies time reversal test, and identifies the critical areas and contribution of the indices to . It produces no bias for polluted or non-polluted regions since effect of outliers is not much. It allows ranking and classification of regions in terms of values and assesses paths of improvement for each region over time. Possible to undertake statistical testing of for the i-th and j-th region at a particular time or for a particular region at two time periods. Since evaluation criteria/base period values vary across countries, meaningful comparison of countries can be made in terms of progress made on Year-to-Year basis. Based on theoretical advantages, the proposed aggregation by Geometric Mean (GM) is an improvement over the existing methods of finding overall pollution status of HMs in soils and is recommended.