STUDYING URANIUM CONTAMINATION ON TRIBAL LANDS IN COLLABORATION WITH UNDERGRADUATE RESEARCHERS

New Mexico EPSCoR’s STEM Advancement Program (STEMAP) provided undergraduate students with summer field and laboratory experiences with research teams involved in EPSCoR’s Energize New Mexico, including New Mexico Tech’s uranium research team. During the five years the program was offered, the team supported five students from the state’s non-graduate-degree granting institutions to study legacy issues on tribal lands of the Navajo Nation and Laguna and Isleta Pueblos. The research focused on understanding the fate and transport of environmental uranium. Uranium mining activities were extensive on several reservations in the 1950s to 1980s, and many of the sites have not been remediated.

In year one and two, three students examined uranium distribution downstream from uranium mining operations on Navajo lands, including locations on TseTah Wash and Cove Wash. The students sampled sediments and, where available, water within and near the stream beds and analyzed them for metals content. In year three, two students conducted a similar study on the drainages below the Jackpile uranium mine in Laguna and Isleta Pueblos. Distance from source areas was a weak predictor of uranium content in the fluvial sediments, but this signal was in many cases overwhelmed by the affinity of uranium to sorb to fine-grained sediment. An important implication is that while sand and aggregate removed from impacted channels may have low concentrations, the fine sediment that collects in low velocity zones such as stock ponds and dirt tanks may be of particular concern.

The team’s final project took a very different path with a project examining the dissolution of metals from dust and fine-grained sediment in two contrasting simulated lung fluids. In this case samples were collected at the Jackpile and St. Anthony uranium mines. Here, students observed different uranium dissolution characteristics depending on whether the source material was fine dust or fluvial silt, presumably bearing sorbed uranium complexes, or crushed mine waste and ore rock, presumably bearing uranium in a mineral phase.