Date of Award

Spring 2021

Degree Type

Thesis

Committee Chair

Katie Hailer

First Advisor

Julie Hart

Second Advisor

Karen Wesenberg

Third Advisor

Alysia Cox

Abstract

Mining in Butte, Montana has been ongoing since the mid-19th century. The US Environmental Protection Agency (EPA) added the Butte Area to the National Priority List in 1983, designating it a Superfund site. Butte is currently part of the largest EPA Superfund site in the United States. The EPA lists arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) as metal contaminants of concern for residents living in proximity to the Butte Area Superfund site. However, very limited human biomonitoring has been conducted in Butte and studies that have been published focus on Pb and, to a lesser extent, As. No synergistic, antagonistic, or additive studies have been conducted, even though it is widely accepted that the exposure in Butte is a metal mixture scenario, rather than single element exposure. Metals that are trace micronutrients, such as copper (Cu), manganese (Mn), and zinc (Zn) have been largely unrecognized as possibly having negative health effects on residents of Butte, despite the fact the metals have been historically released into the soil, water, and air through active blasting and crushing of ore and are known to be potential neurotoxins. This study aims to gather data on metal distribution in soil and dust samples from a neighborhood near active mining operations, determine the bioavailability of the metals present, extract and quantify proteins and inflammatory markers from meconium samples, and investigate metal mixture interactions in human bronchial epithelial cells (BEAS-2B) and human embryonic kidney cells (HEK-293). A physiologicalbased extraction test (PBET), inductively coupled plasma mass spectrometry (ICP-MS), and inductively coupled plasma optical emission spectrometry (ICP-OES) were employed to assess metal distribution and bioavailability. To determine a link between metal exposure and possible health effects, inflammatory markers were measured by enzyme-linked immunoassays (ELISA), and metal-specific proteins were quantified by western blot assays. Metal distribution results showed that As, Mn, and Pb levels were highest in the soil samples, whereas levels of the Cd, Cu, and Zn were highest in the dust samples. The bioavailability of the metals was determined to be highest in the stomach phase for the dust samples and highest in the intestinal phase for the soil samples. Furthermore, expression of the mammalian proteins and cytokines of interest was affected differently by exposure to metal mixtures compared to single metal exposures.

Comments

A thesis submitted in partial fulfillment of the requirements for the degree of Interdisciplinary Masters of Science

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