ANALYTICAL TECHNIQUES APPLIED TO THE SPECIATION OF SELENIUM IN ENVIRONMENTAL MATRICES

The toxicity and essential nature of Se in the environment depend on i ts 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 i ndustrial, agricultural and natural processes. In order to evaluate th e effects of the different Se species on living organisms, sensitive a nalytical methods are required for their determination in complex envi ronmental matrices. An overview is given of the importance of Se speci ation and the distribution, accumulation and transformation of the spe cies in the environment. The state of the art of various techniques is discussed. The main sources of errors in each step involved in the an alytical methods are reported and the importance of quality control an d the need to use reference materials are also stressed.