Spatial patterns of tungsten and cobalt on leaf surfaces of trees in Fallon, Nevada

Abstract

Spatial patterns of airborne tungsten and cobalt are described from leaf-surface chemistry of trees in Fallon, Nevada, where a cluster of childhood leukemia has been ongoing since 1997. In earlier research, airborne tungsten and cobalt have been shown to be elevated in total suspended particulates, surface dust, and lichens from Fallon. To update data on the spatial patterns of airborne tungsten and cobalt in Fallon, leaves were collected in October 2007 from trees growing throughout Fallon. Collected leaves were measured for metals accumulated onto their surfaces. On Fallon leaf surfaces, tungsten and cobalt show maxima of 17 ppm and 6 ppm, respectively, near the center of town, north of Highway 50 and west of Highway 95. These two peaks overlap spatially, and given the dense and widespread pattern of collection, the source area of these two airborne metals can be pinpointed to the vicinity of a hard-metal industry located north of Highway 50 and west of Highway 95. Fallon is distinctive in west central Nevada for its elevated airborne tungsten and cobalt particulates, and given its cluster of childhood leukemia cases, it stands to reason that additional biomedical research is in order to test directly the leukogenicity of combined airborne tungsten and cobalt particulates.