Arsenic: occurrence, toxicity and speciation techniques

The occurrence of arsenic in natural water has received significant attention during recent years. Arsenic exists in the environment in a number of valency states. The valency state of arsenic plays an important role for its behavior and toxicity in the aqueous system. The toxicity and bioavailability of arsenic can only be determined if all its forms can be identified and quantified. Therefore, the aim of this article is to provide a general description of the occurrence of arsenic in the environment, its toxicity, health hazards, and measurement techniques for speciation analysis. Different techniques used for speciation of arsenic, viz., spectrometric, chromatographic, electrochemical, etc. have been discussed.