ANALYTICAL TECHNIQUES APPLIED TO THE SPECIATION OF SELENIUM IN ENVIRONMENTAL MATRICES

The toxicity and essential nature of Se in the environment depend on its concentration and the chemical forms in which it is present. Se and its derivatives may be widely dispersed throughout the environment as a result of anthropogenic inputs such as fossil fuel combustion and industrial, agricultural and natural processes. In order to evaluate the effects of the different Se species on living organisms, sensitive analytical methods are required for their determination in complex environmental matrices. An overview is given of the importance of Se speciation and the distribution, accumulation and transformation of the species in the environment. The state of the art of various techniques is discussed. The main sources of errors in each step involved in the analytical methods are reported and the importance of quality control and the need to use reference materials are also stressed.