The elements considered in this chapter, Li, Be, B, Al, V, Cr, Co, Ni, Se, Sr, Ag, Sn, Sb, Ba, and Tl, occur at the trace or ultratrace level in the crust, with the exception of aluminium which is a major component. Alteration processes involving crustal material bring such elements into the aquatic environment, where they are usually present, including aluminium, at parts-per-billion (ppb - µg/l) or parts-per-trillion (ppt - ng/l) concentrations. However, much higher, undesirable concentrations may occur in some environments, and are caused by: the weathering of mineralised and metal-rich rocks; mining and industrial activities which release trace elements at a rate greater than the natural weathering processes; and high temperature waters which favour the solubility of many trace elements. Table 1 shows the estimated concentrations of trace elements in the aquatic environment, as compared to their abundance in the crust, These values can vary significantly due either to natural processes or to the release from contaminated areas. Nowadays, aqueous inorganic contaminants represent an environmental hazard; industrialised countries in particular face serious contamination levels, and in undeveloped countries there is hardly any attempt at environmental protection. Although the effects of most trace elements in water on the biosphere and human health are not well known yet, many of the elements considered are believed dangerous or potentially harmful. Guidelines for the protection of aquatic life and human health have been established by national and international organisation – such as the U.S. Environmental Protection Agency, the World Health Organization, and the Commission of the European Communities, and values of their recommended concentration in drinking water are shown in Table 2 (10, 11, 12, 13). The guideline values have been changing through time, and more severe regulation has been established as knowledge on the effects of trace elements on the biosphere increases.
Trace elements: Li, Be, B, Al, V, Cr, Co, Ni, Se, Sr, Ag, Sn, Ba, and Tl
CIDU, ROSA
2000-01-01
Abstract
The elements considered in this chapter, Li, Be, B, Al, V, Cr, Co, Ni, Se, Sr, Ag, Sn, Sb, Ba, and Tl, occur at the trace or ultratrace level in the crust, with the exception of aluminium which is a major component. Alteration processes involving crustal material bring such elements into the aquatic environment, where they are usually present, including aluminium, at parts-per-billion (ppb - µg/l) or parts-per-trillion (ppt - ng/l) concentrations. However, much higher, undesirable concentrations may occur in some environments, and are caused by: the weathering of mineralised and metal-rich rocks; mining and industrial activities which release trace elements at a rate greater than the natural weathering processes; and high temperature waters which favour the solubility of many trace elements. Table 1 shows the estimated concentrations of trace elements in the aquatic environment, as compared to their abundance in the crust, These values can vary significantly due either to natural processes or to the release from contaminated areas. Nowadays, aqueous inorganic contaminants represent an environmental hazard; industrialised countries in particular face serious contamination levels, and in undeveloped countries there is hardly any attempt at environmental protection. Although the effects of most trace elements in water on the biosphere and human health are not well known yet, many of the elements considered are believed dangerous or potentially harmful. Guidelines for the protection of aquatic life and human health have been established by national and international organisation – such as the U.S. Environmental Protection Agency, the World Health Organization, and the Commission of the European Communities, and values of their recommended concentration in drinking water are shown in Table 2 (10, 11, 12, 13). The guideline values have been changing through time, and more severe regulation has been established as knowledge on the effects of trace elements on the biosphere increases.
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