Temporal Variability of Tungsten and Cobalt in Fallon, Nevada

Abstract

BackgroundSince 1997, Fallon, Nevada, has experienced a cluster of childhood leukemia that has been declared “one of the most unique clusters of childhood cancer ever reported.” Multiple environmental studies have shown airborne tungsten and cobalt to be elevated within Fallon, but the question remains: Have these metals changed through time in correspondence with the onset of the leukemia cluster?MethodsWe used dendrochemistry, the study of element concentrations through time in tree rings, in Fallon to assess temporal variability of airborne tungsten and cobalt since the late 1980s. The techniques used in Fallon were also tested in a different town (Sweet Home, OR) that has airborne tungsten from a known source.ResultsThe Sweet Home test case confirms the accuracy of dendrochemistry for showing temporal variability of environmental tungsten. Given that dendrochemistry works for tungsten, tree-ring chemistry shows that tungsten increased in Fallon relative to nearby comparison towns beginning by the mid-1990s, slightly before the onset of the cluster, and cobalt has been high throughout the last ~ 15 years. Other metals do not show trends through time in Fallon.DiscussionResults in Fallon suggest a temporal correspondence between the onset of excessive childhood leukemia and elevated levels of tungsten and cobalt. Although environmental data alone cannot directly link childhood leukemia with exposure to metals, research by others has shown that combined exposure to tungsten and cobalt can be carcinogenic to humans.ConclusionContinued biomedical research is warranted to directly test for linkage between childhood leukemia and tungsten and cobalt.

Biological monitoring of tungsten (and cobalt) in workers of a hard metal alloy industry

“…This in part is due to a lack of suitable methods for its determination in both workroom air and biological matrices other than the relatively recent and expensive techniques based on ICP-MS (Keith et al 2007). The occurrence of some childhood leukemia clusters in US areas characterized by high environmental W pollution has recently stimulated a toxicological interest about the element (Koutsospyros et al 2006;Sheppard et al 2007), which may replace molybdenum in human tissues and thus interfere with molybdoenzymes (xanthine oxidase, xanthine dehydrogenase and sulfur oxidase) (Koutsospyros et al 2006). By applying an accurate ICP-MS method, we could determine urinary W in both the worker and the reference group.…”

In vitro profiling of epigenetic modifications underlying heavy metal toxicity of tungsten-alloy and its components

“…Neurological and chronic respiratory problems in metallurgy workers, miners, and in a French soldier exposed to tungsten have been reported Jordan et al, 1990;Marquet et al, 1996). Tungsten exposure via drinking water has been associated with onset of acute lymphocytic leukemia clusters (Rubin et al, 2007;Sheppard et al, 2007;Steinmaus et al, 2004). Tungsten is known to alter phosphatedependent biochemical pathways in a cell-type-dependent manner that may negatively affect downstream cellular functions (Johnson et al, 2010).…”

Use of Dendrochronology and Dendrochemistry in Environmental Forensics: Does It Meet theDaubertCriteria?

“…For example, tree-ring studies have been used to monitor areas contaminated with arsenic (Cheng et al, 2007); fossil fuels (Baes III and Ragsdale, 1981;Balouet and Oudijk, 2006;Balouet et al, 2007;Balouet et al, 2008), heavy metals (Zou et al, 2004;Punshon et al, 2005;Devall et al, 2006;Sheppard et al, 2007), chlorinated solvents (Balouet et al, 2007;Larsen et al, 2008), nutrients (Vroblesky and Yanosky, 1990;Vroblesky et al, 1992), precipitation acidity (Kwak et al, 2008), and radioactive isotopes (Edmunds et al, 2001;Kalin, 1995;Kagawa et al, 2002;Mazeika et al, 2007;Rao et al, 2002). Tree-core studies also have been used to map the subsurface distribution of contamination by chlorinated solvents (Vroblesky et al, 1999;Schumacher et al, 2004;Vroblesky et al, 2004;Doucette et al, 2007;Graber and Soprek, 2007).…”