Investigation of uranium accumulation in sheep bones and cooked mutton

Werner, Emily Kathryn (2023) Investigation of uranium accumulation in sheep bones and cooked mutton. Masters thesis, Northern Arizona University.

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Abstract

The Navajo people consider mutton to be culturally important and have for generations. Mutton is sheep meat and bones that are used in cooking on the Navajo Nation. In 1948, uranium mining by the US government began on the tribal land of the Navajo. In the 1980’s, when the uranium market no longer required such a demand, all the mines were left exposed and abandoned allowing for uranium to become a part of the ecosystem in the southwest; there has only been recent remediation efforts on cleaning up these mine sites. These uranium mine tailings have been contaminating the soil, plants, water, and animals on the Navajo Nation as a result of the lack of remediation. The uranium travels through the water and soil and into plants that are ingested by sheep which are then eaten by the Navajo peoples, potentially causing uranium related illnesses and contamination to tribes in the southwest. In sheep, the uranium can accumulate in their bone and continue to be distributed through their bodies. In this project microwave digestion and inductively coupled plasma mass spectrometry (ICP-MS) were used to quantify the amount of uranium found in sheep meat and bone. Studies have shown that uranyl ions can exchange with calcium in the bone making it a target organ. It was found that sheep bones in Cameron, Leupp, and Eagar had average uranium concentrations of 30.04ng/g, 28.5ng/g, and 48.6ng/g, respectively. A standard reference material (SRM4356) was also analyzed and had an average uranium concentration of 65.74ng/g. Statistically, t-tests (alpha value of 0.05) proved sheep bone from Eagar was different than Leupp and Cameron but similar to SRM4356. Cameron and Leupp were both statically different from SRM4356. Additionally, to find out how much uranium is ingested by Navajo people consuming contaminated mutton, five kinds of cooked mutton (crockpot, boiled, pan-fried, oven-roasted, and grilled) were analyzed. Mutton cooked by crockpot and boiled methods had the highest uranium concentrations of 5.362ng/g and 13.55ng/g and were statistically different than the other methods (alpha value of 0.05). Grilled mutton had the lowest concentration of uranium, 0.2679ng/g even compared to the raw meat and was statistically different than the other methods. By quantifying the contamination amount, additional precautions, and valid advocacy for cleaning up the sites may be achieved.

Item Type:	Thesis (Masters)
Publisher’s Statement:	© Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords:	Mutton; Navajo Nation; Sheep bone; Uranium;
Subjects:	T Technology > TD Environmental technology. Sanitary engineering
MeSH Subjects:	C Diseases > C04 Neoplasms
NAU Depositing Author Academic Status:	Student
Department/Unit:	Graduate College > Theses and Dissertations College of the Environment, Forestry, and Natural Sciences > Chemistry and Biochemistry
Date Deposited:	07 Aug 2026 16:39
Last Modified:	07 Aug 2026 16:39
URI:	https://openknowledge.nau.edu/id/eprint/6334

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