From the
Reno Gazette-Journal:
Laboratory mice developed leukemia-like blood symptoms after Arizona scientists exposed the rodents to
tungsten at levels common in the air and water in Fallon and then exposed them to a common respiratory virus.
The experiments are part of research into the Fallon leukemia cluster that has sickened 17 children and killed three since 1997. The last case in the cluster was diagnosed in 2004.
Mark Witten and Paul Sheppard of the University of Arizona, who have been investigating childhood leukemia clusters in Fallon and Sierra Vista, Ariz., since 2002, exposed mice to tungsten and to a virus.
Four of the six mice have increased numbers of white blood cells, one of the primary indicators of leukemia, Witten said.
"This is the first time it's been shown that an element in nature, in this case tungsten, can possibly cause cancer," he said.
He said the mice will be humanely destroyed and their bone marrow will be analyzed to look for "blasts," abnormal white cells that are the telltale signs of leukemia. The bone marrow also will be checked for traces of tungsten, he said.
The scientists are scheduled to report their results at Experimental Biology 2009, an April 22 conference in New Orleans. The summary of the study was reviewed by a scientific panel before it was accepted for presentation. Cynthia Fastje, who conducted the experiments with Witten, is an author of the report.
Kennametal Inc., which has had a plant in Fallon since the 1960s and operates a refinery north of town, has used tungsten, cobalt and other metals to manufacture products. Previous studies have described the "heavy metals plant" as a "candidate source" of the airborne metal, though Kennametal hasn't been named in the reports.
In previous interviews, Kennametal officials said its plant meets or exceeds all air pollution laws and its presence in the community isn't related to the childhood cancer cluster.
Don Vetter, Kenametal spokesman in Reno, said Wednesday the firm can't comment because nothing has so far been published and the presentation hasn't been delivered.
Tungsten is a naturally occurring element used to make strong metal alloys. Microscopic amounts can be found in soil nearly everywhere in the West, but studies showed Fallon and Sierra Vista have abnormally high levels of the metal in their air. Sheppard and Witten's other Fallon studies have indicated the airborne particles are composed of processed tungsten, not natural tungsten ore.