Chemical Speciation of Chromium in Water: A Review

The investigation of a groundwater resource impacted with Cr(VI) requires analysis of groundwater for Cr(VI) and total Cr. Most notably, Cr(III) is considered to be a trace element essential for the proper functioning of living organisms, whereas Cr(VI) may exert toxic effects on biological systems. The nature and behavior of various Cr forms found in wastewater can be quite different from those present in natural waters because of altered physicochemical conditions of the eluents originating from various industrial sources. The chromium content in surface waters is usually at the low mu gL(-1) level, typically between 0.3 and 6 mu gL(-1). Speciation of Cr(III) and Cr(VI) has been a longstanding analytical challenge. The selective determination of Cr(VI) is of particular importance because of its toxicity. Due to the importance of Cr(III) and Cr(VI), the accurate and sensitive determinations of these ions are the important part of the analytical chemistry. Chromium speciation is very important in different branches of natural sciences. Therefore, total chromium measurements alone cannot determine the actual environmental impact. This requires speciation techniques with sufficient selectivity and high sensitivity. Speciation of trace levels of chromium in water sample requires high-capacity separation and high sensitivity detection. The authors present a review of presently available analytical possibilities of chromium speciation investigations in water samples.