January 19, 2009

Tungsten not as ‘green’ as once thought

U.S. scientists say the metal tungsten -- used in everything from light bulbs to jewelry to bullets -- is not as environmentally friendly as once believed.

Believing tungsten was relatively non-toxic and insoluble in water, the U.S. military in the 1990s developed so-called green bullets containing tungsten as an alternative to lead-based ammunition, Chemical & Engineering News reported Monday.

Studies now show, however, some forms of tungsten move easily through soil and groundwater and can stunt the growth of plants and cause reproductive problems in earthworms.

Tungsten, also used in welding and metal cutting, has been reclassified by the U.S. Environmental Protection Agency as an emerging contaminant of concern, though scientists still believe it is less toxic than lead or mercury, the News reported.