Palmer writes: "New rules proposed by the federal government last year could help reduce the threat of groundwater pollution in drought zones - although industry is fighting to weaken them, along with its Republican allies in Congress."
Orphan Mine, a former uranium mine on the South Rim of the Grand Canyon. (photo: Alan Levine/Flickr)
Why Are We Polluting Groundwater in Drought Zones?
11 September 15
Uranium mining threatens aquifers that could provide the drought-stricken West with emergency water supplies.
ining uranium, the fuel for nuclear reactors, is a dirty business. Following World War II, mining companies extracted millions of tons of uranium from Navajo tribal lands in the West, contaminating homes and water supplies in the process. It went on for decades, and Navajo miners developed lung cancer at very high rates.
Today, even as the U.S. nuclear power industry struggles to survive, uranium mining continues. The techniques are more modern, but conservationists say the threat could be just as insidious: polluting water supplies in drought-ridden parts of the country where drinking water is already alarmingly scarce.
New rules proposed by the federal government last year could help reduce the threat—although industry is fighting to weaken them, along with its Republican allies in Congress. And critics say the proposed regs might not be strong enough, anyhow. Ironically, this might all be happening to extract a resource we barely need anymore—at the risk of one that we most certainly do.
Uranium mining has followed roughly the same arc as oil and gas drilling in this country. Around the turn of the 20th century, finding oil was like finding arrowheads: All you had to do was scratch the ground in California, Texas, or Oklahoma, and there it was. Nowadays, the easy-to-get oil is gone, and more intrusive methods like deep-sea drilling and hydraulic fracturing, or fracking, are needed to keep wells flowing.
Uranium mining started out similarly low-tech in the 1950s, with heavy machinery extracting uranium from open-pit mines close to the surface. Today, as with oil, the United States has just about exhausted those accessible, concentrated sources of uranium, forcing miners to get creative.
The industry must now work with what geologists call “roll-fronts.” These are relatively thin uranium deposits that formed deep underground over the course of thousands of years. Typically just 10 to 30 feet in height—too small to be harvested by human miners—the roll-fronts can only be extracted by chemical means.
The process used today is called in situ recovery, or ISR, mining. (Opponents use the more chemically descriptive phrase “in situ leaching,” or ISL.) The mining company drills four or five holes, called injection wells, and then pumps down a mix of an oxidizing agent (often hydrogen peroxide or simple oxygen) and water. Pressure from the constant influx of fluid forces the solution to percolate through the uranium-rich layer of earth toward another hole, called the production well, which carries it up to the surface. At this point, the company reverses the chemical reaction that dissolved the uranium, using a separate chemical to precipitate the metal out of the water. The water, now stripped of most of the uranium, heads back into the well to continue the cycle.
Uranium miners say the ISR process is less environmentally damaging than open-pit mining. This is, in some ways, a reasonable claim. Single open-pit mines in New Mexico have upset as much as 3,000 acres of land. Waste from the mining process is diverted into ditches and unlined ponds containing radioactive materials. For decades, the federal government exerted almost no control over these mines—and now it’s spending hundreds of millions of dollars cleaning up the sites.
The benefit of ISR mining, say advocates, is that it is nearly a closed loop: The oxidizing solution goes in and brings the uranium out, and when it’s over the area is flushed out with clean water.
In reality, ISR mining isn’t so tidy, and the few peer-reviewed studies available suggest that leaching uranium out of rocks contaminates the surrounding groundwater for decades. As Western states deal with increasing levels of drought, that’s a problem.
Before a company can begin mining for uranium, it’s supposed to prove to the U.S. Environmental Protection Agency that the water in the surrounding aquifer isn’t a good candidate for drinking or other human uses.
Some aquifers naturally have very high salt levels; others are contaminated with radon, uranium, and other heavy metals. The assumption is that there’s no point in protecting an aquifer from uranium mining when nature has already polluted it beyond usefulness. Proving that an aquifer is polluted from the get-go, however, is trickier than it sounds. For one thing, aquifers can stretch for miles, changing in shape and composition throughout.
“In the desert, where you have arroyos and river deltas, there is no homogeneity to an aquifer,” says Rich Abitz, a geochemist who specializes in making models of how hazardous and radioactive chemicals pass through the environment. “An aquifer has multiple layers of silt, sand, gravel, clay, and flow zones within the active channels.”
To characterize the state of an aquifer, uranium companies typically drill a few test wells, then report the water chemistry to the federal government. Most experts call this approach inadequate. “It’s not enough to put in one or two monitoring wells,” says Thomas Borch, an expert in soil contamination at Colorado State University. “You see huge changes in the concentration of radium and uranium in an aquifer depending on where you sample it. What we’re doing is not sufficient to determine the variability and properly characterize the condition of the water at baseline.”
Borch and his colleague James Stone, of the South Dakota School of Mines and Technology, have taken samples at hundreds of sites within an area that a uranium company might consider a single ore zone, and they found that the concentrations of radium and uranium can differ by a factor of 100. In addition, exploring for uranium can itself affect water chemistry. Drilling wells exposes an aquifer to oxygen, and oxidation is exactly the process ISR mining relies on to draw uranium out of the rock and into the water.
“When companies begin exploration, they lay out a 500-by-500-foot grid to identify where the ore bodies are located,” says Abitz. “This is when the baseline measurements should be done, before they drill thousands of bore holes, which releases uranium into the water. They’re disturbing the aquifer prior to baselining. It’s not scientific.”
The uranium-mining companies have themselves produced proof of this problem through a bureaucratic accident. In 2011, Uranium Energy sought permission from the EPA to begin ISR mining in Goliad County, Texas, in an aquifer that most hydrologists believed was nearly pristine. After drilling exploratory and baseline water chemistry wells, the company reported to the EPA that the water was, in fact, rich in uranium.
The agency delayed approval, taking more than 15 months to make a decision. At the end of that period, the EPA forced the company to repeat its sampling. The second set of tests showed uranium levels that were low enough to satisfy drinking-water standards, suggesting that it was the drilling itself—not natural processes—that had drawn the uranium into the water. When the oxidizing process was over, the uranium content returned to its naturally low level.
Despite this troubling revelation and months of hand-wringing, the EPA eventually caved to state and industry interests and allowed mining to go forward, infuriating local residents.
Even when a roll-front provides miners with the uranium they’re after, supplies won’t last forever. After a few months or a couple of years (at most), the watery solution being pumped to the surface contains less and less of the metal, and recovering it is no longer economically viable.
Under current law, however, the mining company can’t simply turn off the pumps and walk away. ISR mining fundamentally changes the chemistry of the groundwater. Oxidation, which draws uranium from the surrounding rock, is probably still occurring within the aquifer, and the metal could still be leaching into groundwater. So the cleanup process, known as remediation, begins.
Most remediations involve two steps. The company first flushes the wells with huge amounts of clean water in an attempt to remove the oxidizing agent and any contaminated groundwater. This process requires millions of gallons of water, which can’t be used again.
Reverse osmosis is the next step. While the technology can be complicated, the theory is not. The company pumps the water that remains in the aquifer through a system of tiny pores to remove as many impurities as possible. Before injecting the water back into the ground, a reducing agent may be added to counteract whatever oxidizing potential is left in the water. This reverse-osmosis process typically runs for a full decade.
Remediation is water- and time-intensive, but does it work? The answer is pretty disturbing: No one knows. There have been only a handful of major studies on the efficacy of the uranium-mining remediation process.
One of the rare peer-reviewed studies, led by Colorado State University’s Thomas Borch and published in 2012, suggests that remediation isn’t particularly effective. Borch and his colleagues used public records to compare the pre- and post-mining water chemistry in a Wyoming well. The “baseline” measurement revealed a uranium concentration of 0.05 milligrams per liter. In February 1999, after eight years of remediation, the uranium concentration was 3.53 milligrams per liter, more than 70 times the pre-mining levels.
To put those numbers into further context, the EPA’s maximum acceptable concentration for uranium in drinking water is 0.03 milligrams per liter. The mining process therefore took water that, with some treatment, might have been safe to drink, and rendered it non-potable for generations.
“Reverse osmosis is good at taking salts out of concentration,” says Borch. “That’s a big deal, because salts ruin agricultural fields. But it can’t get uranium back to baseline levels.”
The aquifer’s problems aren’t limited to uranium. Borch’s study showed that even after years of remediation, radium, arsenic, iron, selenium, barium, and several other contaminants remained high above EPA-recommended levels for drinking water.
“Whiskey is for drinking; water is for fighting.”
Mark Twain allegedly made this statement about the West. Although the authenticity of the quote is in dispute, it sums up the region’s situation fairly well. Drought and water-related strife go hand in hand. Now add uranium mining into the mix. Of the 10 sites currently licensed by the Nuclear Regulatory Commission to conduct ISR uranium mining, all but two are in New Mexico or Wyoming.
Wyoming has experienced seven severe multiyear droughts over the past century. The most disastrous of them began around the last turn of the century and persisted, with only sporadic relief, for 14 years. The state’s farmers suffered badly, with ranchers thinning their herds by 20 percent and most other forms of food production slowing significantly.
Although this dry spell was covered as a freak event in the media, the state has a long history of terrible drought and is the fifth-driest state in the Union. Further, records drawn from tree rings suggest that droughts in the 1200s and 1500s far surpassed anything the state has seen in the last few decades.
New Mexico is even worse off. In 2013, the Los Angeles Times entitled an article “New Mexico Is the Driest of the Dry.” Coming from a newspaper in California—a state that’s dealing with its own water disaster—that is a telling statement. At the time of the report, New Mexico’s reservoirs were at 17 percent of normal, and towns were trucking in water so residents would have something to drink. Some scientists say that the state’s drought is not temporary—parts of New Mexico are experiencing permanents change from grassland to desert. The future for the state’s water is extraordinarily dim.
This is the context in which ISR uranium mining is taking place. These are the factors that must be considered when deciding whether to write off aquifers for decades. Unfortunately, experts say, our laws aren’t consistent with the starkness of this reality.
EPA regulations state that any aquifer containing 10,000 milligrams of dissolved solids (typically salt) per liter of water is automatically not a candidate for drinking water and is open to industrial uses. Even at that level, though, you could make a case that we shouldn’t abandon those aquifers. Although seawater is typically above 35,000 milligrams of dissolved solids per liter, Saudi Arabia is turning hundreds of millions of gallons of it into drinkable water every day. It’s expensive and energy-intensive, but it’s possible.
The rules that apply to aquifers with less than 10,000 milligrams of dissolved solids per liter are largely discretionary. Legally, regulators can write off sub-10,000 quality aquifers only if they are isolated and offer no possibility whatsoever that they’ll be useful to humans in the future. That judgment, however, leaves substantial room for interpretation, and, in practice, energy companies tend to get whatever they want.
“We looked for a denial—an example of an application to extract minerals from an aquifer that was turned down,” says Geoffrey H. Fettus, an attorney at NRDC who works on nuclear issues (disclosure). “We could find none.”
Giving uranium miners access to these mines is akin to opening a Pandora’s box of pollution. Nuclear Regulatory Commission rules state that the uranium miner must return water quality in the aquifer to the levels they found before drilling. If the company proves it cannot achieve those levels, it can fall back on a less aggressive standard: making sure that uranium and other chemicals are reduced to the maximum levels set by regulation. And if even those levels are “not practically achievable,” the company can propose its own contaminant-concentration levels—whatever it believes is safe for the surrounding ecosystems and communities. This is known as the “alternative concentration limit,” or ACL.
In practice, there’s nothing “alternative” about the ACL. No uranium-mining company has ever returned an aquifer to pre-mining concentrations of uranium or other chemicals. Nor has a uranium miner managed to achieve the regulatory maximum levels intended as a fallback. In every single instance, the industry has resorted to the ACL. And the Nuclear Regulatory Commission has let them.
Does the United States even really need the uranium? Despite the enthusiasm of a few vocal supporters like Tennessee Senator Lamar Alexander or Arizona’s John McCain, the future of nuclear energy in the country is uncertain at best. It has been 19 years since a new domestic reactor came online. Due to safety concerns and cost overruns, the country largely gave up on nuclear in the 1980s.
So why the enthusiasm for ISR uranium mining? A strange form of forgetfulness swept across the country about 10 years ago. Call it nuclear amnesia. In the face of climate change, the world needed low-carbon energy, and there stood the nuclear industry, ready to let bygones be bygones. People decided to forgive—or at least forget—all the reasons we abandoned nuclear in the first place.
The delays and the cost overruns that plagued previous reactor projects were assumed, without any evidence, to be a thing of the past. Utilities submitted plans to build dozens of reactors. During this second honeymoon, widely referred to as the U.S. nuclear renaissance, uranium prices surged in anticipation of future demand.
The demand never materialized, and it probably never will. When financiers took a sober look at the case for nuclear reactors, they blanched. Almost all the planned reactors were abandoned, save four that are being built in South Carolina and Georgia. Predictably, all four are behind schedule and overbudget.
Unless the government comes in with massive subsidies, wiping out nuclear power’s inherent economic drawbacks, the industry appears to be dying in the United States. The Clean Power Plan isn’t likely to provide those incentives. Many states can achieve the targets for less money—and with less risk—through energy efficiency and investments in wind and solar. The four new reactors currently under construction (if they are ever completed) cannot begin to compensate for the eventual decommissioning of the 100 or so existing reactors that has already begun. By midcentury, nuclear reactors are likely to contribute a negligible proportion of U.S. electricity, and demand for uranium will dive.
The small amount of uranium the United States would need in the coming decades is easily obtainable on the international market. In fact, our country is already a niche producer of uranium. The leading uranium supplier in the world, by far, is Kazakhstan, with annual production in excess of 23,000 metric tons. The United States produces about one-twelfth as much. Even if we don’t want to rely on authoritarian Kazakhstan for fuel, there are good alternatives. Canada extracts nearly five times as much uranium as the United States, and Australia is also a prolific miner of the metal. Uranium mining is a risky proposition wherever it occurs, but there are places in the world where it’s less likely to threaten supplies of drinking water.
A complete withdrawal of the United States from the uranium game would have virtually no effect on electricity rates. The price of nuclear power comes overwhelmingly from the building of the plant itself. Since uranium contributes a tiny amount to the overall cost, paying a premium to buy from elsewhere will barely register on consumers’ bills.
While the benefits of ISR mining are deeply questionable, the environmental costs are becoming ever clearer to people living near the mining sites. Journalist Abrahm Lustgarten has documented the brewing Western controversy over uranium mining for ProPublica. The most problematic example is in Goliad County, Texas, where, as I mentioned earlier, state officials sought to exempt a pristine aquifer from pollution restrictions.
The EPA initially balked, because the aquifer was neither remote nor particularly briny. In fact, many people drew their drinking water from nearby aquifers, and opponents argued that the company could not prevent excursions—the vertical or sideways migration of the mining chemicals and uranium into the drinking-water supply.
“This is a health issue as much as a water-supply issue," Art Dohmann, president of the local water-management agency, told Lustgarten in 2012.
For the duration of the project—and probably for the rest of their lives—Goliad residents will worry about the consequences of ingesting uranium and radium. Although the two elements are naturally occurring, the human body is only able to tolerate small amounts of them. Elevated doses of uranium can profoundly damage the kidneys, and long-term exposure is believed to raise the risk of cancer.
Radium is an even greater concern, because it’s even more radioactive than uranium. Ingested radium emits alpha particles, and some long-term studies of people exposed to high levels of the substance suggest that it can depress the immune system, increase the risk of breast, bone, and liver cancer, as well as cause anemia and cataracts.
Advocates of uranium and radium mining would argue that these risks are overstated, because the scientific literature is rather thin. That’s partially true—most of the studies are on rodents or a small number of people who consumed relatively low levels of the radioactive chemicals. But the reason for the limited studies is that doctors have had little opportunity to conduct long-term studies on the ingestion of radioactive chemicals, because the government has been successful in limiting exposure.
With the rise of ISR uranium mining, those “opportunities for research” may soon expand, and not just in Goliad County. Wyoming’s Powder River Basin has become a uranium hot spot. Ranchers are supplementing their income with money from mining companies, although often with trepidation. “It's probably worthwhile for this generation,” John Christensen, a large landowner in the Powder River Basin, told Lustgarten. “You just don't know about future generations.”
The EPA’s proposed uranium-mining rules, released on the last day of 2014, address some of the concerns with ISR, but critics argue that they’re not enough. The proposal would allow companies to rely on computer models to shorten monitoring periods, but vague language opens up a major loophole. “The EPA didn’t say what kind of model to use,” says James Stone, who studies heavy-metals transport at the South Dakota School of Mines and Technology. “A model is only as good as the data you put inside it.”
Some scientists also say the rule doesn’t adequately guard against the migration of contaminants outside the well, because miners won’t be required to fully study nearby aquifers before drilling. “If you have an oxidizing zone, down-gradient from the well, the uranium will travel,” says Borch. “That’s why we advocate to characterize not just the roll-front itself, but areas up-gradient and down-gradient from it.”
The EPA’s rules are a good first step, says NRDC’s Fettus, but he warns that there are shortcomings. “There’s a loophole that could allow some existing mines to dodge the requirements by phasing in and out of operation, and the EPA needs to stick with long-term water-quality monitoring backed by sound science,” he says. “Nearby communities deserve that much."
The next few months will be decisive for uranium mining in the United States. And more data is on the way, as professors Borch and Stone (who have secured the cooperation of a major mining company) prepare to release the largest-yet study on the effects of ISR mining on groundwater. The EPA rules will likely be finalized in late 2015 or early 2016. And a major lawsuit over the regulation of the ISR mining —in which NRDC is a party—is wending its way through the Nuclear Regulatory Commission’s Byzantine appeals system.
A study released this year predicted that the West would experience a megadrought during this century—a level of dryness not experienced since the pre-Columbian era. We may have to tell our grandchildren that we risked the one resource we knew they would desperately need, all so we could extract one we could easily have lived without.
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