Geological Society of America

T40 It’s the Dose That Makes the Poison: Advances in Exposure and Dose Assessment for Practical Medical Geology

Monday, 26 October 2020
5:30 PM - 8:00 PM
Meeting Rooms

MINERALOGY DRIVEN LEACHING OF URANIUM FROM AIRBORNE DUST IN SIMULATED BODY FLUIDS, AND POSSIBLE HEALTH IMPLICATIONS

Paper number: T40-4
Program: Technical Sessions
Time: 6:15 PM – 6:30 PM

Authors

Eshani Hettiarachchi Presenting Author
New Mexico Institute of Mining & Technology, SOCORRO, NM
Eshani Hettiarachchi Presenting Author
University of California San Diego, San Diego, CA
Shaylene Paul
Navajo Technical University, Crownpoint, NM
Milton Das
New Mexico Institute of Mining & Technology, SOCORRO, NM
Bonnie A. Frey
New Mexico Institute of Mining and Technology, Socorro, NM
Daniel Cadol
New Mexico Institute of Mining and Technology, Socorro, NM
Gayan Rubasinghege
New Mexico Institute of Mining & Technology, Socorro, NM

Abstract

The recent increase in cardiovascular and metabolic disease in the Navajo population residing close to the Grants Mining District (GMD) in New Mexico is suggested to be due to exposure to environmental contaminants, in particular uranium in respirable dusts. However, the chemistry of uranium-containing-dust dissolution in body fluids and the role of mineralogy are poorly understood, as is their impact on toxic effects. The current study is focused on the dissolution of respirable-sized U-containing-dust, collected from several sites near Jackpile and St. Anthony mines in the GMD, in two simulated lung fluids (SLFs): Gamble’s solution (GS) and Artificial Lysosomal Fluid (ALF). We observe that the respirable dust includes uranium minerals that yield the uranyl cation, UO₂²⁺, as the primary dissolved species in these fluids. Dust rich in uraninite and carnotite is more soluble in GS, which mimics interstitial conditions of the lungs. In contrast, dust with low uraninite and high kaolinite is more soluble in ALF, which simulates the alveolar macrophage environment during phagocytosis. Moreover, geochemical modeling, performed using PHREEQC, is in good agreement with our experimental results. Thus, the current study highlights the importance of site-specific toxicological assessments across mining districts with the focus on their mineralogical differences. Further, the on-going studies conducted with collected dust from same mines in simulated gastro-intestinal fluids suggest that leaching behavior similarly depends on composition of dust.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-359720

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