Earth and Planetary Sciences ETDs

Publication Date

Summer 7-15-2024

Abstract

The inhalation of windblown particulate matter (PM) derived from abandoned uranium mines (AUMs) is a potential environmental health risk to Native American communities that live in proximity to these sites. However, the aeolian transport of metal-bearing PM from AUMs, as a potential exposure pathway, has not been investigated in any detail. In this study, we sampled airborne particulate matter within the Jackpile Mine located on the lands of the Pueblo of Laguna, New Mexico using passive sampling methods to understand the characteristics of dust within the mine site. The objective was to determine the elemental concentrations, mineralogy, and morphology of particulate matter from the abandoned Jackpile uranium mine. The novelty of the study lies in its innovative approach to collecting dust from the Jackpile Mine and conducting a thorough analysis of the particulate matter within the collected samples. This analysis aims to determine whether the mine is producing toxic, metal-bearing particulate matter that could impact the Pueblo of Laguna community.

A comprehensive investigation of the minerals and metals present within dust collected from the Jackpile Mine was performed using scanning electron microscopy (SEM) and inductively-coupled plasma mass spectrometry (ICP-MS) analyses. Dust filters were collected monthly from August 2023 to May 2024 with a total of 80 samples analyzed. Results show that the bulk mineralogy of the dust consists of naturally occurring minerals typical of aeolian dust in the desert Southwest USA (silicates, sulfates, carbonates). Uranium-bearing ore minerals were not found by SEM analyses of the dust particulates. . Similarly, the major elements that were extracted at the Jackpile Mine, such as uranium and vanadium have elemental concentrations that are at or below their crustal averages. However, SEM analysis of the dust did reveal the presence of metal-bearing particulates linked to a range of potential anthropogenic activities. Copper, zinc, chromium, nickel, iron and tin metal PM10 and PM2.5 grains were found during qualitative SEM energy dispersive spectroscopy (EDS) analysis. The morphology of these metal-rich grains, most notably the spherical grains, seems to be associated with combustion and metallurgy activities. Furthermore, ICP-MS revealed that many metals, including molybdenum, arsenic, copper, zinc, nickel, chromium, tin, and cadmium have concentrations above their crustal averages. Most of these metals are not directly associated with the mine or past mining activities, emphasizing inputs from other anthropogenic sources. These results show for the first time that the risks of exposure to windblown hazardous minerals originating from the mine are minimal and are similar to exposures experienced by most of the US population in general. This study therefore directly addresses concerns within the Pueblo of Laguna community regarding exposure to contaminated dust derived from the mine.

Degree Name

Earth and Planetary Sciences

Level of Degree

Masters

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Adrian Brearley

Second Committee Member

Jose Cerrato

Third Committee Member

Eliane El Hayek

Fourth Committee Member

Thomas De Pree

Fifth Committee Member

Joe Galewsky

Project Sponsors

UNM Metals Exposure and Toxicity Assessment on Tribal Lands in the Southwest Superfund Research Program, Museum Research Traineeship, Center for Regional Studies, Research Exploration Connetion

Language

English

Keywords

Metals, Particulate Matter, Dust, Superfund Site, Jackpile Mine, Pueblo of Laguna, Uranium

Document Type

Thesis

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