METALS Research Programs

Environmental Project 1

Immobilization of Uranium, Arsenic, and Co-occurring Metals in Mine Wastes

Investigators:

Jose Cerrato, PhD

Scott Fendorf, PhD

Background:

Exposure to metal mixtures (i.e., uranium (U), arsenic (As), and vanadium (V)) through drinking water poses a risk to Navajo and Laguna Pueblo communities that live near abandoned mine waste sites. Reaction mechanisms involving metal mixtures of ubiquitous secondary mineral phases and the adsorption of locally abundant minerals (e.g., limestone, iron oxides) and plants can potentially reduce metals exposure risk.

Our study:

Dr. Jose Cerrato and his team hypothesize that ubiquitous minerals in mine waste sites can be used to immobilize metal mixtures under surface oxidizing conditions.  Their initial research suggests that the dissolution of U-V and As-Fe mineral phases in mine wastes, combined with rain patterns unique to semi-arid climates, control the release of U and other metals that accumulate in local plants. Using cutting-edge techniques in environmental science and engineering, the research team is investigating reactions and mechanisms at the molecular level to understand macro-scale processes influencing water quality.

Significance:

This research project will develop cost-effective remediation strategies to immobilize metals and prevent degradation of community water sources. The participating Navajo and Pueblo communities and UNM METALS scientists are producing new knowledge that can be applied to remediation strategies for thousands of other existing abandoned mine waste sites. The project will have an invaluable impact on the Native American communities that live in the proximity of abandoned mine waste sites.

Contact:

jcerrato@unm.edu

 

Environmental Project 2

Toxic Metals in Airborne Particulate Matter Originating from Abandoned Uranium Mine (AUM) Sites

Investigators:

Melissa Gonzales, PhD         

Adrian Brearley, PhD

Joseph Galewski, PhD

Background:

Abandoned uranium mines (AUMs) located on tribal lands pose both environmental contamination and public health risks as a result of airborne transport of particulate matter (PM) bearing uranium (U), vanadium (V), copper (Cu), arsenic (As), and other metals. The characteristics of toxic metal mixtures transported from AUM, and the potential for inhalational exposures has not been investigated in a rigorous manner.

Our Study:

This project examines the particle size distributions, mineralogic characteristics, and transport of metal-bearing particulate matter (PM) originating from AUM sites, and the exposure potential to vulnerable tribal populations living nearby. Using state-of-the-art monitoring, chemical, imaging and atmospheric modeling techniques, this project provides valuable information about the the concentrations, speciation, valence, solubility, and other characteristics, of metals by size fraction. These data, currently collected from Blue-Gap Tachee on Navajo Nation and from Laguna Pueblo, are essential to evaluate real-world community exposure and toxicity risk for PM exposure. This work will inform policy regarding risk reduction strategies for tribal communities living in proximity to abandoned mine sites.

Significance:

This project provides comprehensive exposure estimates for toxic metals in PM experienced by tribal communities living in close proximity to AUM. The results will reduce uncertainty regarding the metal content, exposure concentrations and potential toxicity of AUM-related PM exposures in risk reduction and prioritization strategies.

Contact:

MGonzales@salud.unm.edu

 

Biomedical Project 1

Modulation of Uranium and Arsenic Immune Dysregulation by Zinc

Investigators:

Debra MacKenzie, PhD

Laurie Hudson, PhD

Eszter Erdei, PhD

Background:

Working with Native American communities, UNM METALS has obtained evidence for community level exposures and health risks associated with more than 1,100 abandoned uranium mine (AUM) waste sites on their tribal lands. We have further confirmed that community members are exposed to uranium and other metals beyond national norms. To date, there are no significant, community-based health studies describing both exposure and immunologic and cellular outcome measures in these impacted tribal communities.  

Our Study:

Our research shows that certain metals interact with key targets in the cell to disrupt function, specifically zinc-dependent protein function. Dr. Debra MacKenzie, Laurie Hudson, and Dr. Erdei are testing the hypothesis that metals disrupt multiple classes of zinc-binding proteins and that zinc supplements will reduce toxicity to cellular and immunologic functions resulting from metal exposures.

Significance:

This study represents the first human intervention (clinical trial) of zinc supplements to mitigate the adverse effects of mixed metal exposures. The outcomes from these studies will be significant by testing metals and metals mixtures of concern to communities to elucidate impact on and mechanisms of immune dysregulation as detected in exposed populations, and testing the feasibility of a mechanism-based intervention to alleviate the adverse effects of metals exposures.

Contact:

DMackenzie@salud.unm.edu

 

Biomedical Project 2

Mechanisms of Immune Dysregulation Produced by Uranium, Arsenic and Metal Mixtures

Investigators:

Scott Burchiel, PhD

Jim Liu, PhD

The Problem:

Native American communities in the southwestern United States are concerned that uranium and arsenic exposures arising from abandoned uranium mine (AUM) sites might have a role to play in the increased prevalence of metal-associated diseases including immune dysfunction.  Based on published and current research, immature T- and B-cells are extremely sensitive to As toxicity and could be targets of U. Preliminary data indicate that U may interact with As to produce immunotoxicity via both genotoxic (DNA damage) and non-genotoxic (IL-7 signaling) mechanisms.

The Study:

UNM METALS SRP investigators Dr. Scott Burchiel, Dr. Jim Liu and their research teams aim to understand the how arsenic and uranium exposures, alone and in combination may lead to immune dysfunction through T- and B-cell toxicity.

They hypothesize that these lymphoid cells are particularly susceptible to metals toxicity because they lack the ability to export metals. In addition, they are investigating how uranium alone or in combination with other metals interact with zinc finger proteins, such as poly-ADP-ribose polymerase (PARP), to produce toxicity.

Significance:

This work is providing critical mechanistic insights into the potential immunotoxicity of U, its interactions with As and a framework for understanding how interventions, such as Zn supplementation could be used to prevent toxicity.

Contact:

SBurchiel@salud.unm.edu