ABSTRACT
More than 161,000 abandoned hard-rock mines are located in 12 Western states (General Accounting Office [GAO], 2014). Thirteen Western states have the highest percentage of Native American population in the country (U.S. Census Bureau, 2012), creating concerns about the potential for Native American communities in the West to experience disproportionate exposures to mixtures of heavy metals associated with developmental delays and disabilities. Abandoned uranium mines account for more than 4,000 of the 161,000 abandoned hard-rock mines (U.S. Environmental Protection Agency [U.S. EPA], 2008a). In Navajo Nation specifically, more than 500 abandoned mines remain as the legacy of ColdWar mining. These mine wastes represent mixtures of metals including not only uranium, but also arsenic, copper, and other heavy metals, as well as remaining radionuclides. No systematic investigation has been undertaken to understand how exposures in the numerous rural tribal communities in proximity to these wastes might affect health, especially in children. The mine sites are most often unmarked, unfenced, and the historical memory of their location is being lost in the communities. Our research team, working with many Navajo communities, has observed children in direct contact with these mixed metal wastes (see Figure 1). Many successive generations in the communities have grown up in close proximity to these wastes, both during the active mining era and now, when the unremediated legacy wastes remain in their communities (see Figure 2). In 2007, in response to numerous requests from Navajo Nation and affected communities (McSwain, 2007), Congress implemented
the first steps to address this problem through a Five-Year Plan to address uranium contamination on the Navajo Nation (U.S. EPA, 2008b). In 2010 the first health study was added to that plan to understand the relationship between exposures to uranium mining wastes, birth outcomes, and developmental delays in this population: the Navajo Birth Cohort Study (NBCS). Authors of this paper are members of the NBCS study team, including Dr. Lewis, NBCS Principal Investigator. No systematic assessment of the prevalence of adverse birth outcomes and developmental disabilities or delays has been done in this population, despite early suggestions of a potential link between these exposures and congenital malformations (Shields, Wiese, Skipper, Charley, & Benally, 1992).
