Abstract IA44: Disparate exposures of Native Americans to metal mixtures in abandoned mine waste in the West: Implications for cancer risk

Abstract

More than 160,000 abandoned hard rock mines are located in the Western United States that is home to the majority of Native American lands. These mines are estimated to result in more than 500,000 discrete contamination sources. More than 600,000 Native Americans live within 10 kilometers of these mines, which are known to have contaminated at least 40% of the headwaters of western U.S. watersheds. Abandoned gold mines and uranium mines dominate the inventory in proximity to tribal lands, with more than 4,000 abandoned uranium mines associated with more than 10,000 individual waste sites. The proximity of Native populations to these sources, and their greater reliance on local resources, creates a pattern of greater than anticipated exposures to the waste through multiple pathways including ingestion of unregulated drinking water, plant and animal products raised in contaminated soils, inhalation of windblown dusts containing waste metals, and direct contact with indoor dusts. Native communities have greatly reduced access to regulated drinking water sources, creating a reliance on unregulated sources potentially contaminated by waste. These waste sites all include a combination of heavy metals geologically collocated with the primary metal of concern, and often are combined with chemicals used in the extraction process. Data compiled by Indian Health Services illustrate significant health disparities within these communities, including a shorter life expectancy and double the mortality rate for those under 44 years of age. Cancer mortality rates for the Native American population increased over the 20-year period from 1990-2009, a period during which rates for the White population have decreased. Exposure to metals such as cadmium and arsenic has been directly linked to cancer mortality in Native populations, and epidemiologic data from one community proximal to an abandoned uranium mill report 4 of every 10 residents have died of cancer. Recent work in our laboratories has shown inhibition of DNA repair as well as dysregulation of immune function to be associated with exposures to these metal mixtures, providing possible pathways underlying increased cancer risk. Disparities do not end with exposures, but continue as patients seek care. With the closest treatment options often hundreds of miles away over extremely rough roads, using gasoline significantly more expensive than in many urban areas, the impact of increased risk continues to manifest throughout diagnosis and treatment. Citation Format: Johnnye Lewis. Disparate exposures of Native Americans to metal mixtures in abandoned mine waste in the West: Implications for cancer risk [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr IA44.