Blogs

How my laboratory group in the College of Pharmacy at the University of New Mexico (UNM) came to be in Blue Gap Tachee, Arizona—a small chapter in the middle of the Navajo Nation—is a story for another time, but there were several factors sufficient enough to garner our interest:

1. There is a large abandoned uranium mine site;
2. Dozens of residents of the Blue Gap Tachee chapter were willing to attend chapter meetings to discuss the health effects of heavy metals and process for reclamation; and
3. It was obvious that the mine waste was directly feeding the main Tachee wash (also called an arroyo or dry river bed), which fed the entire canyon during rain events. No, it does not rain often, but this arroyo is clearly an important drainage point that the agricultural community utilizes for crops and livestock.

Not many people live in Blue Gap Tachee. On a clear day, when the air pollution is low, a particulate matter monitor provides an accurate count of passing vehicles in the four-hour period during the exposures. About six. The 2010 census lists the area’s population at a little over 1,100, which means the potential public health burden of this uranium mine is minor compared to, say, the levels of particulate air pollution seen in New Delhi or Shanghai, but mining is a global activity and very often the most impacted communities are indigenous, whether in the United States, Mongolia, Kazakhstan, or elsewhere. Five hundred or so uranium mines have been left abandoned throughout the Navajo Nation (with many more throughout the Western United States), but no active mining has been ongoing since the late 1980s. So, it was with some trepidation that our lab began its effort to study how metals from the abandoned mine contaminated nearby air and water and, therefore, could be affecting the health of the area’s population, but it is easy to find the motivation to help people, especially when those people are directly asking for your help.

The abandoned mine site we are studying—known as “Claim 28”—sits on the southern edge of a broad sandstone mesa west of Chinle and south of Kayenta, Arizona. For decades, the Blue Gap Tachee community has expressed concerns about contamination arising from the Claim 28 site, which sits upstream and often upwind of most of the people living here. Prior to our current research project, my colleagues Jose Cerrato, Johanna Blake, Sumant Avasarala, Chris Shuey, and Paul Robinson had begun to detail how heavy metal contaminants are still in high levels at the surface of the mine site and how these metals move downstream to the wash. However, no one had considered how metals from the mine site might travel as particulates in the air. To compress a long and painful story down to a single sentence, our lab received a National Institute of Environmental Health Sciences (NIEHS) grant to study this, in collaboration with the good folks at Michigan State University (Jack Harkema, Masako Morishita, and Jim Wagner), who loaned us the AirCARE1 mobile laboratory we would use for the research. It also should be noted that our Michigan State University collaborators, especially Ryan Lewandowski, suggested we would be cleaning the particle concentrator on a daily basis to keep it functioning. We have really not had to clean it much at all and it works great. Apparently, our particles are just not as sticky as those in Detroit and Los Angeles. Hotter, maybe.

Before I share more about our research into the uranium mine and its health effects, a few observations about this mobile laboratory project that will never make it into a manuscript:

• We parked the mobile laboratory right on top of a red ant hill. Not advised.
• Installing electricity to the trailer at the mine site was an ordeal. First, the trailer needs three-phase power, and only single phase was available. We solved that with some expense, but easily enough. The second, larger obstruction was getting a permit (for whatever it was we were doing) from the Navajo Tribal Utility Authority (NTUA). We thought we would only be there for three months, which requires a temporary-use permit, but it took six months to get the permit, such that the NTUA chastised us for trying to get the wrong permit. Clearly, we did not fit into any simple category on the permitting request, which made decision making by the NTUA difficult and ultimately required approval from the Navajo Nation president. I like seeing his signature on the approval, though. I may have to sell it on eBay when this is all done.
• When we had the trailer on the University of New Mexico campus, after it had been parked and electricity was installed, our parking attendants hunted me down. Despite ample parking availability in this area, the parking department wanted to charge a daily rate for all spots taken by the 53-foot trailer. No matter how important you think your research is, your institutional parking department will simply not care. As a hint, get chummy with your university’s CFO.
• At the Claim 28 site, we stay in a spare cabin of a local resident, Sadie Bill. The cabin is rustic and aged, but provides a major convenience since there is no such thing as Airbnb on the Navajo Nation. Two to four people are usually stationed in the cabin while we are running the mobile lab, as it is a four-hour drive from UNM. It has water—a sink and a toilet—but no water heater and no shower. And there is electricity. We started with the approach of “roughing it” with camping gear, such as a camp stove and sleeping bags. As the weeks went on, certain indulgences started appearing. A coffee pot. A hot water pot. A microwave. A large, flat screen TV. Xbox.
• As with most of life, duct tape and WD40 solve 90% of problems in the trailer.

Now, back to the uranium, which is an interesting metal in terms of toxicity and biological interactions. It poses risk not only as a radiological hazard, but also as a heavy metal. Naturally occurring uranium does not produce much radioactivity, as its composition is dominated by the ²³⁸U isotope (about 99%) rather than the ²³⁵U isotope used for energy. However, when I obtained samples of uranium ore via eBay, it did not go over well with my radiation safety officer.  

Uranium does not seem to absorb well when ingested, but it has a long residence time in the lung when inhaled. During large-scale mining from the 1940s through 1980s (in parallel with the Cold War), many people experienced high levels of occupational exposure. These exposures led to clear incidences of lung cancer and kidney disease. Decades later, colleagues at UNM are finding that uranium miners may be at increased risk of cardiovascular disease, even compared to people who mined other minerals. A recent county-level lung mortality analysis showed the four-corners region to be a hotspot for silicosis and sarcoidosis, likely related to occupational exposures. And this is consistent with another fact about these mines: Other contaminants, such as silica, vanadium, arsenic, and cadmium, are often present, as well. Claim 28, for instance, has a high vanadium content.

In discussions with the Blue Gap Tachee community, which often occur in the native Navajo language through interpreters, they have expressed many worries about how contaminants from the mine site may move through the water, soil, and air to cause health problems. It is an important, but challenging discussion, translating the language as well as the science. The Navajo people have seen several dramatic changes to their life experience in the past 50 years. There is an increased abundance of inexpensive processed food and the obesity and diabetes rate has increased considerably. In parallel, increased access to quality health care is extending the lifespan of the general population, which for better or worse leads to numerous aging-related diseases that were previously rare. Mining activities also caused diseases that the Navajo people had never seen before, like lung cancer and kidney disease. With the low population, it is very hard to epidemiologically ascertain what other new diseases may be related to low-level chronic exposures. Autoimmune diseases seem to be a major new issue. Neurological diseases, as well.

Listening to the community members’ concerns does not always provide a concrete roadmap for research. No one from this rural, largely agrarian region is asking whether uranium impacts their epigenetics or pluripotency, and I will never be able to tell them that uranium caused specific cases of asthma or dementia or diabetes in the face of all the other exposures, diet, and lifestyle choices that may have occurred. While our scientific objective is to provide quality information to help justify a government-funded cleanup of the site, an important role to me is to let the residents of Blue Gap Tachee know that toxicologists are willing to listen, contribute their expertise, and give voice to their concerns.

EDITOR’S SIDEBAR: A Geographic and Historic Overview of the Claim 28 Site

The Blue Gap Tachee originates in the northern part of the canyon and travels south, creating a deep cut through the otherwise flat central plain of the canyon floor. There are a lot of cow paths that descend the 15 or so feet into the arroyo and then back up the other side. Coming face-to-face with a wolf while constrained by those 15-foot walls has diminished my interest in taking any more of the casual jogs that I used to enjoy (Good doggie. Stay doggie). 

The mesa where Claim 28 sits rises up about 500 feet from the Blue Gap Tachee floor to an elevation of 7,200 feet, where the oxygen level is about 23% less than at sea level. Our research team has made the climb several times to explore, and it is always a little harder than it looks. If you follow the mesa to the north and east about six miles, it continues to climb in elevation, such that the cliff walls dramatically and majestically fall more than 1,000 feet down to the town of Rough Rock. This is just south of Monument Valley and west of Canyon de Chelly.

This whole region used to be underwater millions of years ago. It is interesting to imagine this landscape submerged—the mesa tops may have been islands, while the canyon floors, where people live now, would have been deep sea. Several years ago, in the Mesa Verde National Park, about 100 miles away from Claim 28 beyond the Lukachukai Mountains and San Juan River, my then-five-year-old son found a seashell fossil in a small sandstone rock at an elevation of about 7,000 feet. That rare, small fossil holds an unnaturally large influence on my perception of this planet and my son.

Like the Mesa Verde site, just adjacent to our work site, there is a small, isolated mesa which displays evidence of an ancestral Puebloan (still referred to as Anasazi by the local residents) dwelling. The summit is given the Navajo name “Taasahdi Dzil”—please do not ask me to pronounce it, as my Navajo is terrible. Along with the ruins of a dwelling, pottery shards are strewn about. Our Navajo partners have strong reservations against entering the dwelling or handling the pottery, but they did not mind our gently dusting off the shards, so all could have a better look at the intricate artwork. Needless to say, we did not take any souvenirs besides pictures—despite the remote nature of this site, I can only imagine how much looting has occurred over the past century.

Smarter people than I may have a way of assessing how old the site and pottery are, but I am guessing more than 800 years old. It is a small dwelling, nowhere near the grandiosity of the palaces at Chaco Canyon, Mesa Verde, or Aztec, New Mexico. Eking out a subsistence lifestyle in this parched region of the country is a sobering, yet comforting thought. There are enough resources here to sustain communities, but only just barely. The Anasazi disappeared—a reminder that this region can be extremely vulnerable to anything that disrupts the ecosystem balance, such as a prolonged drought. Or heavy metal toxicants. There is a major gap in the history of the ancestral Puebloan people. It is not known why they abandoned their elaborate stone dwellings or where they went. Assimilation into other tribes, such as the Navajo, Hopi, or Apache, seems rational, but when resources are tight, conflict between the tribes also may be a likely answer to what happened to the Anasazi.