A Bayesian Framework for Estimating Disease Risk Due to Exposure to Uranium Mine and Mill Waste on the Navajo Nation

Abstract

Summary More than 1100 abandoned mines, milling sites and waste piles from the uranium mining period are scattered across the Navajo Nation, resulting in exposures to environmental metals, including uranium. The Diné Network for Environmental Health project began in response to concerns regarding the community health effects of these environmental exposures on chronic disease. The paper presents the results of the initial Diné Network for Environmental Health survey of 1304 individuals living on the Navajo Nation. We examine the relationship between uranium mine waste exposure and kidney disease, diabetes and hypertension. These chronic diseases are found at high prevalences in the study population, present major public health risks and have been linked to metals exposures in other studies. We model the exposure–outcome relationship by using a multivariate model for the three binary responses. We implement a Bayesian multivariate t‐model, which has marginal log‐odds ratio parameter interpretations and is computationally efficient. In examining environmental exposures, appropriately adjusting for potential confounders is pivotal to obtaining policy relevant effect estimates. We use Bayesian model averaging to account for uncertainty in the functional form for confounding adjustment within a small set of measured confounders. Using this multivariate framework, we find evidence of associations between these chronic diseases and both historic mining era and legacy mining exposures.

Inhibition of poly(ADP-ribose)polymerase-1 and DNA repair by uranium

“…Many of these abandoned waste sites are located on or in proximity to Native American lands in the West where existing disparities in health raise additional concern of vulnerability to environmental toxicant insults. Studies by our group and others have indicated that community members living in proximity to uranium contaminated sites have an increased likelihood of developing chronic diseases including hypertension, kidney disease, and diabetes (Wagner et al, 2010; Hund etal., 2015); as well as immune dysfunction and autoimmunity (Lewis, 2013; Lu-Fritts et al, 2014). Our research group has also found that urine uranium concentrations within the Navajo population are greater than the national norms, underscoring the need for additional studies within these exposed communities (Lewis, 2013).…”

“…Human exposure to uranium is often linked to occupational exposures such as mining activities, living in proximity to mine waste sites, or increased use of depleted uranium for industrial or military purposes (Craft et al, 2004; Brugge et al, 2005; Miller and McClain, 2007; deLemos et al, 2009; Briner, 2010; Brugge and Buchner, 2011; Hund et al, 2015). Natural uranium is a heavy metal predominantly comprised of two isotopes, 235U and 238U.…”

Residential proximity to abandoned uranium mines and serum inflammatory potential in chronically exposed Navajo communities

“…We recently reported that uranium mining exposure was associated with hypertension in the Navajo population. 6 A handful of studies found links between arsenic exposure and circulating biomarkers of inflammation (e.g., intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), C-reactive protein (CRP)). 7,8 However, assessment of single circulating factors (e.g., cytokines, etc.)…”

Reactive Transport of U and V from Abandoned Uranium Mine Wastes

“…1, 2 For instance, the negative health impacts of human exposure to uranium (U) and vanadium(V) through inhalation and ingestion have been well documented. 3, 4 Uranium and V co-occur at numerous abandoned mine waste sites on the Navajo Nation territory near the four corners region of the southwestern U.S. 5, 6 Uranium and other co-occurring metals from these mine wastes can be released into neighboring water resources affecting their water quality.…”