Chromium in Anthropogenically Polluted and Naturally Enriched Soils: A Review

Abstract Chromium (Cr) is a very important element examined for last decades on many expert fields. Its toxicity, mobility and bio-availability are strongly dependent on its oxidation state, Cr(III) and Cr(VI). Hexavalent form Cr(VI) is a known carcinogen with many harmful effects on living organisms, on the other hand trivalent Cr(III) form is an important micronutrient necessary for lipid metabolism. Contamination of the environment by Cr may come from anthropogenic industrial pollution or from naturally enriched sites, especially ultramafic rocks and their derived soils. Environmental conditions of soils and water represent a very complex system, which makes reliable assessment of its fate and potential toxicity and transport a really difficult task. A number of studies have been performed to describe Cr behaviour in these systems, as well as to optimize its determination, especially speciation methods. The main objective of this contribution is to summarize and present the today’s knowledge about the occurrence, speciation, and behaviour of Cr in soil environment, with a specific emphasis to description of differences between naturally enriched and anthropogenically contaminated soils.