Uranium is a naturally occurring, radioactive element. This element is often found in nature and can be mined and processed into a metal.1 The processed metal has played a major role in military weapons programs and power generation. But today its legacy  lives on in people’s homes and drinking water. Researchers are continuing to explore the journey of uranium’s migration into drinking water, the possibility for harm, and the innovation necessary for clean-up.

How does uranium get into drinking water? From Water Near Weapons Factories, Phosphate-Fertilized Farms, and Uranium Mines

Uranium appears naturally in rocks, soil, and groundwater. The element is typically in very low levels that do not pose a risk to humans and animals.1 The Environmental Protection Agency (EPA) has set the maximum contaminant level for uranium in drinking water as 30 µg per liter.2 Despite that limit, levels of uranium may be higher than normal near factories that process uranium. Uranium is used to build weapons. Farms also use uranium in phosphate fertilizer. Lastly, uranium is processed in uranium mines.1 Uranium-contaminated soils can pollute groundwater near these sites, which may then appear in drinking water supplies and water sources used for irrigation and homes.2

For example, families and individuals in the Navajo Nation live near uranium mines and mills, where approximately 30 million tons of uranium ore were extracted between 1944 and 1986. Although the mines are closed today, 500 abandoned mines remain on the land, and groundwater has elevated levels of radiation.4 The EPA has warned that people living near the mines are at risk of drinking contaminated water by using unregulated water supplies or not following safe water collection practices.4

In addition, high levels of uranium have recently been reported in farming regions of the western United States, which are due to over-pumping of natural groundwater reserves that have uranium content. In some regions, drought or irrigation needs may cause water scarcity. In an effort to collect water groundwater pumping pulls surface water deep into the Earth, which is then tapped by wells that supply drinking water.5 In 2015, researchers at the University of Nebraska reported that nearly two million Americans in California’s Central Valley and the Midwest live within a half-mile of groundwater containing unhealthy levels of uranium, so concerns about uranium-contamination are widespread.5

What are the effects of uranium contamination? Kidney Damage and Risk of Cancer, and Lots of Money

The Centers for Disease Control and Prevention (CDC) has classified the chemical effects of drinking uranium as a greater concern than the effects of possible radiation from contact exposure.2 Although bathing and showering with uranium-contaminated water does not pose a serious health risk, drinking contaminated water can lead to several issues.2 Kidney damage is the most likely outcome of exposure to uranium-contaminated drinking water. The CDC also cautions that drinking water with uranium may increase an individual’s estimated lifetime risk of cancer because of the radioactive elements (although the base of evidence supporting this claim is not definitive at this time).5

Beyond the health impact, there are also social and economic effects of uranium contamination. Like any type of drinking water contamination, the problem poses serious cost to taxpayers. For example, in 2015, the city of Modesto, California, spent over a half million dollars to blend the water of a uranium-contaminated well with other water sources to dilute the uranium to safe levels.5 In fact, Modesto’s cost of diluting its water supply is only a drop in the bucket of total costs for the state: The California Water Resources Control Board has reported that the state has spent over $16.7 million since 2010 to address public water systems with high levels of uranium.5

What are possible solutions to uranium contamination? Test Your Water

Fortunately, there are actions individuals can take to test and to treat their own water, which is especially important for homes with private wells. People with private wells must routinely test their own water supply, and certified water testing laboratories can test for the presence of uranium. If there is a level of exposure above the allowable amount, people must install a household water purification unit, connect to a public water supply (which is already tested and treated), or use bottled water if no other option is available.6

Like in Modesto, cities and states can also take action against contaminated sources of drinking water by diluting the supplies down to safe levels or closing contaminated wells altogether; however, testing and treatments are expensive and may not eliminate the source of contamination.5 Federal laboratories are also working to clean up contaminants left behind by governmental weapons programs, such as by excavating and transporting contaminated soil. Again, this intervention is also expensive and may present issues for safe relocation and disposal of the uranium-contaminated soil.

Another Solution: Innovative Technology

Researchers at Stanford University and the Oak Ridge National Laboratory are developing a possible solution to these issues by converting dissolved uranium into a solid form that is not transmittable by water.3 The research group created a recirculation loop, so contaminated groundwater was brought to the surface, treated, and reinjected in an ongoing fashion for over a year. The treatments included removing contaminants, adding acidity and ethanol to the recirculating water, and growing microbial agents that converted the uranium to an immobile form.3 This means that after a year of treatment, the uranium remained like a rock in the soil without dissolving into the groundwater. Ultimately, the team was successful in reducing uranium contamination in a sample of groundwater from over 1,000 times the drinking water regulatory limit down to 30 µg per liter.3

Uranium is widely present in drinking water, and individuals who have private wells, live near current or former uranium mines and processing plants, or who live near farms should be especially vigilant. We can be encouraged, though, as researchers and public officials make progress in addressing this issue and reducing uranium contamination.

References

1. Stephanie Pappas. July 24, 2017. “Facts About Uranium.” Live Science. https://www.livescience.com/39773-facts-about-uranium.html
2. Centers for Disease Control and Prevention. Jan. 10, 2017. “Community Water.” https://ephtracking.cdc.gov/showUraniumHealth.action
3. Hannah Hickey. May 19, 2006. “For uranium cleanup… a bacteria?” Stanford News. https://news.stanford.edu/news/2006/may24/criddle-052406.html
4. Environmental Protection Agency. “Cleaning Up Abandoned Uranium Mines.” https://www.epa.gov/navajo-nation-uranium-cleanup/cleaning-abandoned-uranium-mines
5. Associated Press. December 8, 2015. “‘You can get cancer’: Uranium contaminates water in the West.” CBS News. https://www.cbsnews.com/news/uranium-contaminates-drinking-water-in-us-west/
6. North Dakota Department of Health. October 2015. “Uranium in Drinking Water Fact Sheet.” https://deq.nd.gov/Publications/WQ/1_GW/uranium/UraniumInDrinkingWaterFactSheet.pdf

On August 5, 2015, 3 million tons of toxic sludge leaked into the Animas River in Colorado, giving its waters a bright yellow hue. According to most news sources, the leak was caused by a team of workers employed by the Environmental Protection Agency.1 The Gold King Mine has been leaking fluids into its surrounding area since its shuttering in 1923. This has resulted in the formation of dozens of toxic wells in its immediate vicinity. In order to contain this environmental disaster, work crews from the EPA have been attempting to “slurp out the worst pools of sludge and dispose of them properly.”2

But while they were working near Silverton, some of their heavy equipment “disturbed an earthen wall that secured the liquid, releasing an up to 80-mile ribbon of pollution downstream.”2 The contaminated water contains high levels of heavy metals, “including lead and arsenic.”1 A few days later, water tests after the spill indicated that levels of arsenic and lead were respectively at “300 and 3,500 times the normal levels.”2

EPA Promises to Do Better, But Farmers and City Near Gold King Mine Suffer

Since then, the EPA has owned up to causing the incident. Also, EPA has promised prompt rectification measures and the establishment of new oversights to better prevent a similar spill.2 That aside, the incident compromised the livelihood of many farmers situated along the Animas River and its tributaries. The incident also affected the city of Durango was also affected. That city draws a significant amount of its water supply from the Animas River. And much of its tourist trade depends on “water-based recreation.”3

Fortunately, no one died because of this spill. So far, current reports indicate that park agents and biologists working for La Plata County have found no significant amounts of dead fish or animals in or beside the polluted water bodies. This means that the polluted water poses little danger to fish or other wildlife.4 But the long term consequences of this incident remain to be seen.

Arsenic Spilled into the Animas River

Despite the well known, adverse health effects of exposure to heavy metal contaminants, worldwide people continue using heavy metals today. For example, one major pollutant is arsenic. Arsenic spilled into the Animas River. A metalloid, arsenic occurs naturally in rock, soil, water, and air. Its inorganic form is present in groundwater used for drinking in several countries all over the world. Meanwhile, its organic compound is primarily found in fish.5 It can also come into contact with humans through pesticides, wood preservatives, and contaminated food and water. Moreover, contaminated “soils such as mine-tailings… [are another] potential source of arsenic exposure.”5

Similarly, inorganic arsenic is also extremely toxic. “[I]ntake of large quantities leads to gastrointestinal symptoms, severe disturbances of the cardiovascular and central nervous systems, and eventually death. In survivors, bone marrow depression, haemolysis, hepatomegaly, melanosis, polyneuropathy and encephalotopathy may be observed.”5 Individuals exposed to arsenic through drinking water face “excess risk of mortality from lung, bladder, and kidney cancer.”5

Mines Leak Lead, Which Could Hurt Children in Particular

The other major pollutant, lead, is another common metal used frequently in many modern day products. Most notably, burning petrol produces in lead emissions. Similarly, working in mines, smelters, or battery plants may expose individuals to lead. All of these places give off high levels of lead emissions that suffuse their surrounding area. This causes airborne lead to “be deposited on soil and water, thus reaching humans via the food chain.”5 Acute lead poisoning causes headaches, irritability, abdominal pain, and various nervous system-related symptoms. In particular, lead poisoning more drastically harms children. In addition to other symptoms, children may suffer from behavioral disturbances as well as learning and concentration difficulties. Long-term exposure to lead can result in permanently diminished mental faculties in adults and stunted growth in children.5

Mines Must Manage Their Waste Water – Passive and Active Treatment

Since exposure to heavy metal contaminants can result in such harms to human health, mines must scrupulously manage their waste water. Most mining operations recognize this and develop “water management plans to minimize the potential for water contamination… and to prevent the release of polluted water into the environment.”6 Some mines use water control techniques, such as diverting surface and drainage water from the mine site, recycling water used for processing ore, using evaporation ponds for contaminated water, and installing liners and covers on waste rock and ore piles to prevent them from coming into contact with groundwater.6

Whereas other mines take their measures one step further by treating the contaminated water produced by their operations with technologies that can be categorized as either active or passive. In active water treatment, acidic mine waters are treated with alkaline compounds such lime, limestone, or caustic soda. The elevation of the pH levels causes dissolved metals to precipitate and to sink to the bottom of the sedimentation ponds that hold this water. Subsequently, people can remove these sediments. Other technologies such as ion exchangers, membrane filters, and reverse osmosis might also be used to achieve a similar effect.6

In contrast, passive water treatment relies on “natural physical, chemical, and biological processes that remove water… [contaminants] without additional physical or chemical inputs… [Some] of these processes include bacteria-controlled metal precipitation, contaminate uptake by plants, and filtration through soil and sediments.”6 Thus, these mines rely on constructed wetlands in which natural mechanisms filter and purify contaminated water. After that, the water can rejoin other water bodies. But passive water treatment requires constant, challenging water monitoring. As a result, it can be ineffective when dealing with highly acidic water.

Gold King Mine, Trying Everything But the Balance Did Not Work

Around Gold King Mine, the work crews were trying to control the contaminated water with a variety of the aforementioned methods. Mainly, they used evaporation ponds and combined active and passive water treatment processes in a bid to induce metal precipitation. Despite their efforts, a sudden accident and error in judgment on their part caused massive quantities of lead and arsenic to flow into the Animas River.

Although the effects of the spill have so far been relatively minor, no one knows the long-term consequences yet. Mining is an essential aspect of the global economy. As a consequence, calls to curtail or reduce mining operations are unreasonable and unproductive. Nonetheless, mines could definitely benefit from improved sustainable water management technologies directed at the prevention of any contamination issues. Save the WaterTM is a non-profit organization focused on the development of water science. Any contributions you can make to our research and development endeavors will help us to prevent an incident like the Animas River spill from ever occurring again.

References

1. Kaylee Heck. August 10, 2015. “Three Million Gallons of Contaminated Water Turns River Orange in Colorado.” ABC News. http://abcn.ws/1gsZJSo
2. Tony Dokoupil. August 10, 2015. “EPA owns up to toxic sludge leak tainting Colorado river.” MSNBC. http://www.msnbc.com/msnbc/epa-owns-toxic-sludge-leak-tainting-colorado-river
3. Erinn Morgan. August 10, 2015. “Durango copes with ‘orange nastiness’ of toxic sludge river pollution.” http://bit.ly/2GuubtL
4. Alex Johnson. August 11, 2015. “Colorado River Spill: Early Tests Show Little Threat to Fish, Wildlife.” NBC News. http://nbcnews.to/1gweP9P
5. Lars Järup. December 1, 2003. “Hazards of heavy metal contamination.” British Medical Bulletin. http://bmb.oxfordjournals.org/content/68/1/167.long
6. Miningfacts.org. “How is water managed and treated in mining?” http://www.miningfacts.org/Environment/How-is-water-managed-and-treated-in-mining/