The military began substituting tungsten (left) for lead cores in bullets after 1999.

Tungsten May Not be Best Material for 'Green' Bullets

Researchers added small amounts of tungsten to the drinking water of laboratory mice and found that the material concentrated in their spleen and bones.

Scientists are reporting new evidence that a prime alternative material for bullets — tungsten — may not be a good substitute. The report, which found that tungsten accumulates in major structures of the immune system in animals, appears in ACS’ journal Chemical Research in Toxicology. To see the full article, click on the title: “Tissue Distribution of Tungsten in Mice Following Oral Exposure to Sodium Tungstate.”

Jose Centeno, who works at the Armed Forces Institute of Pathology, and colleagues explain that tungsten alloys have been introduced as a replacement for lead in bullets and other munitions. It resulted from concern that lead from spent ammunition could harm wildlife when it dissolves into water in soil, streams, and lakes. Scientists thought that tungsten was relatively non-toxic, and a “green” replacement for lead. Recent studies suggested otherwise, and with small amounts of tungsten also used in some artificial hips and knees, Centeno’s group decided to gather further information on tungsten.

They added small amounts of a tungsten compound to the drinking water of laboratory mice, used as surrogates for people in such research, and examined the organs and tissues to see exactly where tungsten ended up. The highest concentrations of tungsten were in the spleen, one of the main components of the immune system, and the bones, the center or “marrow” of which is the initial source of all the cells of the immune system. Further research, they say, will be needed to determine what effects, if any, tungsten may have on functioning of the immune system.

The authors acknowledge funding from the Naval Health Research Center Detachment — Environmental Health Effects Laboratory.

Source: American Chemical Society

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