A new study confirms what others have shown before - a high level of tungsten and cobalt in Fallon, where a childhood leukemia cluster has sickened 17 children. Three have died since 1997.
Researchers said the latest study was done by collecting surface
dust from various surfaces around the community 60 miles of Reno.
However, scientists said the testing doesn't pinpoint the origin of
the metals, or whether they are linked to the cancer cluster.
The latest results of dust collected in 2005 support findings of two previous studies, said Dr. Paul Sheppard, a researcher at the University of Arizona and one of the study's main authors.
"This is yet another study giving evidence of the elevated levels of tungsten and cobalt in Fallon," he said. "We have co-aberration from the three studies," he told the Lahontan Valley News.
One of the previous studies revealed high levels of tungsten and cobalt in algae and moss at elevations above 3,900 feet. The other was an airborne study.
Sheppard said the latest study indicates tungsten levels at 934
parts per million, and cobalt at 93 ppm.
But since there's no current data on safe non-occupational exposure levels, the numbers only indicate high levels and suggest more biochemical testing should be conducted, he said.
"The occupational exposure is not transferable to outdoor non-occupational exposure standards," he said.
Elevated levels of tungsten have also been found in biological samples taken from Fallon residents and in local water supplies.
Dr. Gary Ridenour of Fallon, who assisted in the study, said much of the particles in the samples was probably old stuff around the town before better EPA standards were being used at Kennametal, a Fallon manufacturer of tungsten-carbide products used in tools.
Sheppard and Dr. Mark Witten, also from the University of Arizona, were the principal investigators on the study.
Others involved include Dr. Robert Speakman from the Museum Conservation Institute, the Smithsonian Institution in Suitland, Md.; Dr. Michael Glascock from the Research Reactor Center at the University of Missouri; and Calvin Farris from the University of Missouri.