Using Lichen Chemistry to Assess Airborne Tungsten and Cobalt in Fallon, Nevada

Abstract

This paper describes the use of lichen chemistry to assess airborne tungsten and cobalt in Fallon, Nevada, where a cluster of childhood leukemia has been on going since 1997. Lichens and their rock substrates were collected from Rattlesnake Hill within Fallon as well as from four different rock outcrops located north, east, south, and west of Fallon and at least 20 km away from the town center. In the lichens themselves, W and Co are significantly higher within Fallon than in the combined control site outside of Fallon. In the rock substrates of the lichens, no differences exist in W and Co. The W and Co differences in lichens cannot be attributed to substrate geochemistry. Fallon is distinctive in west central Nevada for high airborne W and Co, and given its cluster of childhood leukemia, it stands to reason that additional biomedical research is in order to test directly the leukogenicity of combined airborne W and Co.

Spatial patterns of tungsten and cobalt in surface dust of Fallon, Nevada

“…Fallon is distinctive from nearby comparison towns in Nevada as well as from outlying desert areas because of significantly elevated tungsten and cobalt in total suspended particulates and in lichens (Sheppard et al 2006(Sheppard et al , 2007. This present study fine-tunes the spatial patterns of tungsten and cobalt using surface dust within Fallon.…”

“…Rocks collected within Fallon as well as from desert sites around Fallon show normal concentrations of tungsten and cobalt (Sheppard et al, 2007). Soils of residential Fallon and nonresidential outlying (Sheppard et al 2006(Sheppard et al , 2007. …”

“…Prior research has included drinking water (Moore et al 2002), jet fuel (US ATSDR 2002), pesticides (US CDC 2003a), surface water (U.S. ATSDR 2003a), outdoor air (US ATSDR 2003b), surface soil and indoor dust (US ATSDR 2003c), potential lingering effects of underground nuclear bomb testing in the area (Seiler 2004), and groundwater (Seiler et al 2005). Although few definitive conclusions have been made, significantly elevated airborne tungsten and cobalt levels have been identified in airborne particulates within Fallon relative to comparison towns (Sheppard et al 2006) and in lichens within Fallon compared to outlying desert areas (Sheppard et al, 2007). Toxicological research on effects of tungsten and cobalt on leukemia has been recommended, as has additional environmental research in Fallon to improve understanding of its airborne tungsten and cobalt.…”

Temporal Variability of Tungsten and Cobalt in Fallon, Nevada

“…Fallon is distinctive spatially by its elevated airborne tungsten and cobalt relative to comparison towns and outlying desert areas (ATSDR 2003a; CDC 2003b; Sheppard et al 2006a, 2007c). Now, based on replicated tree-ring chronologies of multiple metals and backed up with an independent test of dendrochemistry of tungsten around a known source of tungsten, Fallon is also distinctive temporally by its increase in tungsten beginning by the mid-1990s as well as by its elevated cobalt since at least the early 1990s.…”

“…A theory known as population mixing has also been proposed for Fallon (Kinlen 2004; Kinlen and Doll 2004). Among other environmental findings, a consensus has emerged that the heavy metal tungsten is elevated in Fallon (CDC 2003a; Sheppard et al 2006a, 2007b, 2007c). Cobalt also is elevated in Fallon (ATSDR 2003a; Sheppard et al 2006a, 2007b, 2007c).…”