Tungsten: Environmental pollution and health effects

Tungsten, an element of moderate abundance in nature, is used widely by society in a variety of applications. The environmental and toxicological behavior of tungsten and its compounds remain, for the most part, unknown. Tungsten’s chemistry, one of the most varied and complex among the transition elements, is similar to that of molybdenum whose essentiality in living systems is well established. To date, tungsten’s essentiality is limited to some prokaryotic organisms and thus a biological role for this element in humans is difficult to establish. The earth’s crust is the pool of tungsten in the ecosphere where it exists in trace amounts. Tungsten and its compounds turn up in the other environmental domains via a variety of transformation and transport mechanisms of natural or anthropogenic source. Enrichment is observed in various environmental systems, however, its magnitude and extent are difficult to assess due to lack of available data. Tungsten effects on plants and microorganisms vary widely from adverse via indifferent to beneficial depending on prevailing conditions and genotype. Animal studies to determine possible human health and toxicity effects of tungsten and tungsten compounds are rather limited compared to other metal substances.