Effect of Intermittent Flow on Metals Mobilized from Native American Abandoned Uranium Mine Waste Sites
Tuesday, February 23, 2016: 1:30 p.m.
Sumant Avasarala
,
Civil Engineering, University of New Mexico, Albuquerque, NM
Jose Cerrato
,
Civil Engineering, University of New Mexico, Albuquerque, NM
Abdul Mehdi Ali
,
Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM
Kateryna Artyushkova
,
Chemical Engineering, University of New Mexico, Albuquerque, NM
Ricardo Gonzalez Pinzon
,
Civil Engineering, University of New Mexico, Albuquerque, NM
Column experiments were conducted to study the effect of intermittent flow on the mobility of metals from abandoned uranium mine waste sites in Blue Gap Tachee (BGT), Arizona and Laguna, New Mexico during surface water infiltration to groundwater resources. Intermittent flow represents the rainfall patterns in the southwestern United States, involving alternate wet and dry cycles. In order to simulate these rainfall patterns, shorter wet periods of 15, 30, 60, 120, and 360 minutes, followed by longer dry periods of 24 hours, were adopted for the column experiments. The experiment involved sequential leaching of sediments from Laguna and BGT with 18MὨ water (pH 5.4), synthetic rain water (SRW, pH 5.6), 10mM bicarbonate solution (pH 7.9) and 10mM acetic acid (pH 3.4) solution that represent the environmentally relevant conditions as witnessed in BGT water samples (pH 3.8 and 7.4). With just 18MὨ water and SRW almost 90 µg/L of U, 4500 µg/L of V and 20 µg/L of As were released from BGT mine waste while the Laguna sample showed the release of 380 µg/L of U, 2 µg/L of V, and 40 µg/L of As. The released U concentrations were 3-13 times its EPA MCL for U which under natural circumstances could threaten the proximate communities. Bicarbonate and acetic acid extractions on the other hand released 3500-6000 µg/L of U, 50-3000 µg/L of V, and 14-35 µg/L of As from both Laguna and BGT mine waste respectively. For reference, the columns were also leached continuously with bicarbonate and acetic acid for a week (each), to identify if the phases were kinetically or thermodynamically controlled. A 1D reactive transport model is also being applied to better interpret the role of these interplaying mechanisms.
Sumant Avasarala, Civil Engineering, University of New Mexico, Albuquerque, NM
Sumant Avasarala is a graduate student in the Department of Civil Engineering of the University of New Mexico pursuing a Ph.D. towards understanding the fate and transport of metal mixtures from mine waste sediments in surface water and groundwater resources.
Jose Cerrato, Civil Engineering, University of New Mexico, Albuquerque, NM
Jose Cerrato’s research interest is related to biogeochemical processes at the interface of water and energy that affect the cycle of metals and radionuclides in the environment. He leads the E-H2O Research Group which applies spectroscopy, microscopy, aqueous chemistry, and molecular biology tools for the study of complex environmental interactions.
Abdul Mehdi Ali, Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM
Abdul Mehdi Ali is responsible for Analytical Chemistry Laboratory Management, which includes operation, maintenance, and troubleshooting of highly specialized computer controlled instruments. He is responsible for data processing, validation, and quality assurance and quality control measures, implementing approved analytical protocols, the laboratory quality assurance plan, and standard operating procedures for sample analyses.
Kateryna Artyushkova, Chemical Engineering, University of New Mexico, Albuquerque, NM
Kateryna Artyushkova is currently a Research Associate Professor in the Chemical and Nuclear Engineering Department at the University of New Mexico and Associate Director of the Center of Emerging Energy Technologies. Her research focuses on developing methodology for accelerating material design through structure-to-property modeling and characterization of functional materials using ex-situ and in-situ spectroscopic and microscopic techniques. She manages the surface analytical facility of the Center of Emerging Energy Technologies at UNM.
Ricardo Gonzalez Pinzon, Civil Engineering, University of New Mexico, Albuquerque, NM
Ricardo Gonzalez Pinzon is an assistant professor in the Civil Engineering Department of the University of New Mexico. His research interests are hydrologic transport, rainfall-runoff processes, stream ecology, groundwater-surface water interactions, smart tracers, and mathematical and computational modeling.
