The ethical issues in uranium mining research in the Navajo Nation

Uranium and Associated Heavy Metals in Ovis aries in a Mining Impacted Area in Northwestern New Mexico

The objective of this study was to determine uranium (U) and other heavy metal (HM) concentrations (As, Cd, Pb, Mo, and Se) in tissue samples collected from sheep (Ovis aries), the primary meat staple on the Navajo reservation in northwestern New Mexico. The study setting was a prime target of U mining, where more than 1100 unreclaimed abandoned U mines and structures remain. The forage and water sources for the sheep in this study were located within 3.2 km of abandoned U mines and structures. Tissue samples from sheep (n = 3), their local forage grasses (n = 24), soil (n = 24), and drinking water (n = 14) sources were collected. The samples were analyzed using Inductively Coupled Plasma-Mass Spectrometry. Results: In general, HMs concentrated more in the roots of forage compared to the above ground parts. The sheep forage samples fell below the National Research Council maximum tolerable concentration (5 mg/kg). The bioaccumulation factor ratio was >1 in several forage samples, ranging from 1.12 to 16.86 for Mo, Cd, and Se. The study findings showed that the concentrations of HMs were greatest in the liver and kidneys. Of the calculated human intake, Se Reference Dietary Intake and Mo Recommended Dietary Allowance were exceeded, but the tolerable upper limits for both were not exceeded. Food intake recommendations informed by research are needed for individuals especially those that may be more sensitive to HMs. Further study with larger sample sizes is needed to explore other impacted communities across the reservation.

Why Has It Taken So Long to Address the Problems Created by Uranium Mining in the Navajo Nation?

Following the start of uranium mining after World War II, progress toward addressing the hazards it created for workers and nearby communities was slow, taking many decades. This essay asks why it took so long and suggests several factors that might have contributed.

Applying bioethical principles to place-based communities and cultural group protections: the case of biomonitoring results communication

In this article, an argument is made for extending bioethical principles to place-based community and cultural group protections when there are conflicting perspectives on reporting individual results of biomonitoring studies. Bioethical principles of beneficence, nonmaleficence, respect for autonomy, and justice can incorporate participatory decision-making and understandings of the group conditions of individual research participants, particularly for research studies with vulnerable groups. Arguments for and against biomonitoring communication to individual participants are reviewed here. Assessments of risks and benefits of biomonitoring communication can be improved by considering the contextual conditions of cultural groups and place-based communities. Providing participatory decision-making with all stakeholders about biomonitoring communication can provide more fair benefits than adopting a general, prescriptive clinical standard that favors only group report-backs when clinical utility is low and the scientific understandings of low dose exposures of chemical contaminants to humans are still uncertain.

Photoactivated uranyl ion produces single strand breaks in plasmid DNA

Uranium is an important emerging toxicant whose use has outpaced the rate at which we are learning about its health effects. One unexplored pathway for uranium toxicity involves the photoactivation of uranyl ion by UV light to produce U(5+) and oxygen radicals. The purpose of this study was to provide proof of principle data by testing the hypothesis that coexposures of DNA to uranyl acetate and UVB irradiation should produce more DNA strand breaks than individual exposures. Results supported the hypothesis and suggest that investigations of uranium toxicity be expanded to include skin as a potential target organ for carcinogenesis, especially in populations with high uranium and high UV radiation exposures.

Early child development and developmental delay in indigenous communities

Developmental delay is common and often responds to early intervention. As with other health outcomes, the prevalence of developmental delay may be socially determined. Children in many Indigenous communities experience increased risk for developmental delay. This article highlights special conditions in Indigenous communities related to child development. It addresses the challenges of screening and evaluation for developmental delay in the context of Indigenous cultures, and in settings where resources are often inadequate. It is clear that careful research on child development in Indigenous settings is urgently needed. Intervention strategies tied to cultural traditions could enhance interest, acceptability, and ultimately developmental outcomes in children at risk.

Drinking water with uranium below the U.S. EPA water standard causes estrogen receptor-dependent responses in female mice

BACKGROUND

The deleterious impact of uranium on human health has been linked to its radioactive and heavy metal-chemical properties. Decades of research has defined the causal relationship between uranium mining/milling and onset of kidney and respiratory diseases 25 years later.

OBJECTIVE

We investigated the hypothesis that uranium, similar to other heavy metals such as cadmium, acts like estrogen.

METHODS

In several experiments, we exposed intact, ovariectomized, or pregnant mice to depleted uranium in drinking water [ranging from 0.5 microg/L (0.001 microM) to 28 mg/L (120 microM).

RESULTS

Mice that drank uranium-containing water exhibited estrogenic responses including selective reduction of primary follicles, increased uterine weight, greater uterine luminal epithelial cell height, accelerated vaginal opening, and persistent presence of cornified vaginal cells. Coincident treatment with the antiestrogen ICI 182,780 blocked these responses to uranium or the synthetic estrogen diethylstilbestrol. In addition, mouse dams that drank uranium-containing water delivered grossly normal pups, but they had significantly fewer primordial follicles than pups whose dams drank control tap water.

CONCLUSIONS

Because of the decades of uranium mining/milling in the Colorado plateau in the Four Corners region of the American Southwest, the uranium concentration and the route of exposure used in these studies are environmentally relevant. Our data support the conclusion that uranium is an endocrine-disrupting chemical and populations exposed to environmental uranium should be followed for increased risk of fertility problems and reproductive cancers.