UNM Professor is Focused on Fate of Uranium in Water

April 21, 2014

José M. Cerrato, a new assistant professor in the UNM Department of Civil Engineering, has a smile that lights up a room when he talks about his work.

"I feel blessed to have this job because it is not merely technically teaching a subject," he says. "It is impacting people's lives."

Cerrato came to UNM from Washington University in St. Louis, Mo. where he was working as a post-doctoral researcher. He was a member of the Stanford Synchrotron Radiation Lightsource Science Focus Area (SSRL SFA) Research Team, sponsored by the U.S. Department of Energy, investigating the stability of uranium (IV) products resulting from in-situ bioremediation. Cerrato is originally from Honduras, where he received his bachelor's degree in civil engineering.

"I decided to work on water and environmental issues in Honduras and that inspired me to get a degree in environmental engineering," Cerrato said. He was awarded a Fulbright - Organization of American States Scholarship and received his master's and Ph.D. from Virginia Tech where he focused on the biogeochemistry of manganese and other metals in drinking water systems. He is a former fellow of the Virginia Tech EIGER NSF Integrative Graduate Education Research Traineeship (IGERT).

At UNM he is a member of a team of researchers from New Mexico Tech and UNM working on a major National Science Foundation NMEPSCoR grant to identify strategies for the development of long-term energy resources in New Mexico. He is the lead principal investigator (PI) of the E-H2O Research Group, a member of the Center for Water and The Environment, and a research project principal investigator for the University of New Mexico (UNM) Metals Exposure and Toxicity Assessment on Tribal Lands in the Southwest (METALS) Research Center.

The Uranium Transport and Site Remediation team is looking carefully at how uranium moves in the environment. Since uranium (VI) is usually soluble in water, researchers are looking at ways to transform it to uranium (IV), a much less soluble form. Another alternative to immobilize soluble uranium is through the precipitation of less soluble forms of uranium (VI). Ultimately the team would like to understand whether there is a way to contain the element safely in the natural environment.

Uranium fate and transport is a critical issue in New Mexico because decades of uranium mining have left contaminated underground aquifers in the northwest quadrant of the state. Water with high concentrations of uranium is toxic to humans and animals because it can cause serious kidney problems and cancer.

Cerrato will be working in the laboratory to understand how uranium moves at the interface of soil and water. The team is particularly interested in exploring how bacteria might be used to change uranium (VI) into uranium (IV) and whether uranium (IV) can be stabilized so it does not move freely in the environment. "The question we have as engineers is how do we know that this uranium (IV) is going to be stable for a long time," he said.

In the past, much of the uranium mining in New Mexico has been on land owned by Native Americans and the U.S. government. Both groups are interested in the results of the research because there is renewed commercial interest in uranium mining in the state.

Preliminary studies have already been conducted under the auspices of the NM EPSCoR Uranium Transport and Site Remediation team and the UNM METALS Center to characterize abandoned mine wastes. These preliminary studies were performed with permission of the Navajo Nation EPA and in collaboration with officers and residents of the Tachee-Blue Gap Chapter of the Navajo Nation in Apache County, Arizona, and staff of UNM METALS Center partner Southwest Research and Information Center (SRIC).

Mine waste samples were collected from the abandoned Claim 28 mine and related sites near Tachee Wash, along with samples of local non-impacted soils. Metal content of soil and waste samples were determined by X-ray photoelectron spectroscopy and X-ray fluorescence in collaboration with Abdul-Mehdi Ali, senior research scientist in Earth and Planetary Sciences, Kateryna Artyushkova, research associate professor in the UNM Dept. of Chemical Engineering, and Sumant Avasarala, Ph.D. student in the Dept. of Civil Engineering who is sponsored by NM EPSCoR.

These analyses determined that wastes contain 0.01 % uranium(VI), 0.49% arsenic(0), and 1.03% vanadium(V) by weight, while all these metals were below detection limits in samples of non-impacted soils. Metals identified in abandoned mine wastes could be released to surface water and groundwater sources and into the local air shed, posing risks to human health through multiple pathways.

The NM EPSCoR Uranium Transport and Site Remediation team is in the first year of a five-year grant so initial results are expected to be released in the next year and a half.

Cerrato is a faculty affiliate of the Latin American & Iberian Institute.