Tungsten-alloy shrapnel might cause cancer.An alloy containing tungsten tungsten (tŭng`stən) [Swed.,=heavy stone], metallic chemical element; symbol W; at. no. 74; at. wt. 183.85; m.p. about 3,410°C;; b.p. 5,660°C;; sp. gr. 19.3 at 20°C;; valence +2, +3, +4, +5, or +6. , cobalt, and nickel turns wounds cancerous within a few months, a test in rats shows. The finding raises questions about the current military practice by many countries of using this alloy in bullets and other ammunition as a replacement for uranium and lead.
Biochemist John F. Kalinich of the Armed Forces Radiobiology Research Institute The Armed Forces Radiobiology Research Institute (AFRRI) is a triservice laboratory chartered by the U.S. Congress in 1961, conducts research in the field of radiobiology and related matters essential to the operational and medical support of the U.S. in Bethesda, Md., and his colleagues surgically embedded pellets of the alloy, which is 91 percent tungsten, into the animals' leg muscles. Separate groups of rats received pellets made of predominantly of nickel or tantalum tantalum (tăn`tələm) [from Tantalus], metallic chemical element; symbol Ta; at. no. 73; at. wt. 180.9479; m.p. 2,996°C;; b.p. 5,400±100°C;; sp. gr. 16.65 at 20°C;; valence +2, +3, +4, or +5. , a heavy metal.
Within 5 months, all the rats getting the tungsten-alloy pellets died of cancers that had spread from their wounds to their lungs. The nickel pellets also caused fatal cancers at the animals' wound sites, but not in their lungs. The rats with embedded tantalum didn't develop any malignancy malignancy: see cancer. and lived for a year. The researchers report the findings in an upcoming Environmental Health Perspectives.
Tungsten has no history of causing cancer, but nickel and cobalt do. "Whether the presence of tungsten is the key factor in the alloy's carcinogenicity carcinogenicity /car·ci·no·ge·nic·i·ty/ (kahr?si-no-je-nis´i-te) the ability or tendency to produce cancer.
the ability or tendency to produce cancer. needs further research," Kalinich says.