Fracking and Groundwater Contamination: The Known and the Unknowns

By Roberta Attanasio, IEAM Blog Editor

Peak oil, or peak water? Peak water might be the (unfortunate) answer. Alternative sources of energy may become more widely available, but there are no alternatives to water. The ongoing depletion of groundwater contained in aquifers—one of the most important sources of water on our planet—is a significant threat to our future. Many countries are already near or beyond peak water, and results from recent studies show that significant segments of Earth’s population are consuming groundwater all too quickly, without knowing when it might run out.

CA dust bowl sign

A common sight along California’s interstate 5, throughout California’s agricultural heartland. Credit: Joshua L, CC BY 2.0.

Even in the United States, many areas are already experiencing groundwater depletion—mostly caused by sustained overpumping. Increased demands on groundwater resources have overstressed aquifers all around the nation, not just in arid regions. The vast Central Valley aquifer system that underlies California’s heartland, has been named one of the most stressed worldwide. It is heavily utilized for agriculture, and the overpumping keeps escalating due to the record-breaking drought, which is exacerbated by record hot conditions. The disturbing experts’ viewpoint is that California’s farmers “are eroding their buffer against future droughts and hastening the day when they will be forced to let more than a million acres of cropland turn to dust because they have exhausted their supplies of readily available groundwater.” There is no doubt that water is the new gold.

However, we are not only pumping too much, we are also putting this scarce resource at risk to compromise the remaining groundwater by polluting it with toxic chemicals, most notably through fracking.

fracking waste pipe

Fracking fluid and other drilling wastes are dumped into an unlined pit located right up against the Petroleum Highway in Kern County, California. Credit: Faces of Fracking, CC BY-NC-ND 2.0.

Fracking, or hydraulic fracturing, is the process of extracting oil or natural gas by injecting wells with fracking fluids, which contain water, sand, and toxic chemicals, at extremely high pressure. Fracking a single well requires between two and five million gallons of local freshwater, and generates enormous amounts of contaminated wastewater. The wastewater is kept in lined pools above ground or is injected deeper into the earth using waste-injection wells. As expected, there have been highly controversial incidents of reported groundwater contamination.

Last summer, California state officials suddenly shut down several waste-injection wells in Kern County. According to state documents obtained by the Center for Biological Diversity, almost three billion gallons (the equivalent of 454 Olympic swimming pools) of oil industry wastewater containing fracking fluids and other pollutants were dumped into Central Valley aquifers—legally protected under the federal Safe Drinking Water Act—through at least nine injection disposal wells. The Central Valley Water Board tested eight water supply wells out of more than 100 in the vicinity of the disposal injection wells. In half the water samples, arsenic, nitrates, and thallium exceeded the maximum contaminant level.

The state of California was delegated primary responsibility for implementing the Class II oil and gas underground injection control program of the federal Safe Drinking Water Act in 1983. Thus, dumping wastewater into Central Valley aquifers has been called an illegal activity by the Center for Biological Diversity. However, a few months ago, SFGate reported that companies were allowed by the state to drill these wells into aquifers suitable for drinking or irrigation: “The problem developed over decades, starting with a bureaucratic snafu between state and federal regulators. It was made worse by shoddy record keeping and, critics say, plain negligence.”

What’s the industry point of view on groundwater contamination? Rock Zierman, chief executive officer of the California Independent Petroleum Association, which represents smaller oil companies in the state, told SFGate: “If we’re not able to put the water back, there’s no other viable thing to do with it. If you were to shut down hundreds of injection wells, obviously that’s a lot of jobs, a lot of tax revenue.” Does that mean it’s OK to contaminate groundwater and accept consequences such as a dwindling drinking water supply, irrigation of crops with polluted water, and barren croplands?

In 2014, the U.S. Environmental Protection Agency (EPA) directed the state of California to submit a Revision Plan for the underground injection control program. The state submitted its Program Revision Plan on February 6, 2015 and is now required to meet a February 15, 2017 compliance deadline under heightened EPA oversight. But how frequent is groundwater contamination caused by fracking around the country? It’s hard to know, because researchers are unable to investigate many of the suspected contamination cases. Why? Settlement details are sealed from the public when energy companies settle lawsuits with landowners.

Eric Wohlschlegel, a spokesman for the American Petroleum Institute, in an interview released to the New York Times in August 2011, dismissed the assertion that sealed settlements have hidden problems with gas drilling. He added that countless academic, federal, and state investigators conducted extensive research on groundwater contamination issues and found that drinking water contamination from fracking is highly improbable. However, a 1987 report had already highlighted a case of groundwater contamination in West Virginia. And, in December 2011, the EPA released a report indicating that contaminants included in fracking fluids polluted central Wyoming underground water, likely as a result of the gas-drilling process. The report was expected to be a turning point in the heated debate on the contribution of fracking to contaminating groundwater, but it was touted as inconclusive and lost ground.

Now the debate can count on new undeniable findings. Contamination caused by Marcellus Shale gas production has been reported for Pennsylvania groundwater. Results from a recent peer-reviewed study demonstrate that natural gas and other contaminants migrated laterally through kilometers of rock at shallow to intermediate depths, impacting an aquifer used as a potable water source. The study’s authors concluded that data from similar incidents should be released publicly in order to avoid similar problems through use of better management practices.

There are reasons to hope for a reversal in oil and gas industry denial of groundwater contamination and its related environmental and public health effects. Long-awaited re­ports are providing momentum to fuel the already hot debate on groundwater pollution caused by fracking.

On June 4, 2015, the EPA released its assessment of the risks the fracking process poses to the nation’s drinking water supply. The report executive summary states: “There are above and below ground mechanisms by which hydraulic fracturing activities have the potential to impact drinking water resources.” The summary also states: “We did not find evidence that these mechanisms have led to widespread, systemic impacts on drinking water resources in the United States.” However, it points out: “We found specific instances when one or more mechanisms led to impacts on drinking water resources, including contamination of drinking water wells.”

fracking aerial

Fracking-dense countryside, showing web of roads, pipelines and well pads. Credit: Simon Fraser University – University Communications, CC BY 2.0.

A detailed examination of the chemical pollution impacts of fracking, commissioned by CHEM Trust and released on June 21, 2015, states that “Fracking has the potential to have a massive impact on the countryside and those who live in it – be it people, livestock or wildlife. The potential scale of fracking operations is huge, creating major water pollution risks from the large amount of chemicals used, and wastewater generated.”

Finally, on July 9, 2015, the California Council on Science and Technology released its long-awaited final assessment of fracking in California. It highlighted the use of highly tox­ic chem­ic­als, which are mostly uncharacterized in terms of potential ef­fects on groundwater, wild­life, and crops. The report concluded that these effects remain “uninvestigated, unmeasured, and unknown. Basic information about how these chemicals would move through the environment does not exist.” In the other words, the report’s major findings seem to be that we are clueless about the potential effects of fracking on the environment. The report also points out that over half of the wastewater is disposed of in pits that allow water to percolate into the ground, where it could easily contaminate groundwater.

gas drilling pond aerial

Gas drilling well pad and ponds. Credit: Beyond Coal and Gas, CC BY 2.0.

Jane Long, the report’s co-lead, told the Los Angeles Times that researchers did not find strong evidence of fracking fluids in irrigation water. However, she added: “What we did find was that there was not any control in place to prevent it from happening.” Senator Fran Pavley pointed out in a press release that fracking, as well as all oil and gas drilling and waste-disposal activities, should be done transparently. “Government agencies, the public in general, and residents living near well sites need to know in detail about the presence of dangerous chemicals mixed in water used in fracking and then pumped to the surface as byproducts,” she said, adding that she will make every effort to pass legislation that takes into account recommendations from the report, including the phasing out of about 900 percolation ponds that threaten to taint groundwater.

On December 17, 2014, Governor Andrew M. Cuomo’s administration announced that it would ban hydraulic fracturing in New York State. On June 1, 2015, Maryland’s ban on hydraulic fracturing became law—in stark contrast with the law signed by Texas Governor Greg Abbott on May 18 that precludes cities and towns from passing ordinances that prohibit fracking and regulate underground activity. This measure effectively banned fracking bans, like the one passed by the city of Denton, Texas, last November. If history is any indication, the fracking debate will go on, fiercely and untamed, for years to come, and will involve scientists, regulators, residents, environmentalists, and—of course—the oil and gas industry.

In 2010, Rex W. Tillerson, the chief executive of ExxonMobil, said at a Congressional hearing on drilling: “There have been over a million wells hydraulically fractured in the history of the industry, and there is not one, not one, reported case of a freshwater aquifer having ever been contaminated from hydraulic fracturing. Not one.” As this statement has now been demonstrated to not be true, let’s prioritize protecting our groundwater and stop polluting it.

9 thoughts on “Fracking and Groundwater Contamination: The Known and the Unknowns

  1. BillK

    There a few good things happening: A) Low oil prices are slowing down the fracking industry. Sorry for those involved in the industry (at all levels) that will economically suffer after years of gain, but this is good for the environment. B) Because of the downturn, frackers are becoming more creative, as they need to save money. Instead of using precious clean water they’re turning to toilet water. In Texas, some frackers will be using municipal reclaimed water coming from sewage plants that treat human waste. C) The Obama administration proposed last month to cut methane emissions from US oil and gas production by half over the next decade. The fracking industry will be required to repair leaks and capture gas that escapes from wells. D) Not so good: development and use of renewable energy is too slow. Renewable energy is what will make fracking and similar practices obsolete and useless.

  2. Leanna El-Sheikhdeeb

    Reading through this article, I felt disappointed with all of the different actions going on. Water is one of the most limited sources that we have and we can not make more of it. When something is worth such an incredible value, we do not damage it and we try to sustain it as much as we can. The world only has access to about one-thirds of the remaining freshwater because the other two-thirds are locked up in glaciers and ice caps. Rivers in Rio Grande and Colorado are discharging little to no water because of over pumping groundwater. With ground water and aquifers, the amount of water taken out must be returned or the level of water must return to a certain point before pumping again to prevent running out. Also with climate factors, scientists have been giving us precautions that their will be more droughts and storms and natural disasters that might be more than what they predict or less. This means we need to really be careful of our actions and need to make further plans to sustain water as much as possible.
    Over pumping is becoming a huge issue but now we are also damaging the only water we have. This seems as if we are being lazy with trying to figure out other solutions to deal with scarce resources. Fracking requires at least a couple of millions of gallons of freshwater and still generates wastewater which does not make sense. It is almost as if we have a problem and to deal with it we dump it in a huge amount of freshwater that is now becoming limited and developing a even bigger problem of contaminated wastewater. California is a main state that is experiencing this problem and they are also one of the states that is running out of water. Shouldn’t there be any rules or laws set on fracking by each state or by United States as a whole? In some states you can not collect rain water but in some states you can dump waste water in aquifers? This does not make sense. Yes, we were having a huge oil problem but now with lowering oil prices we do not need to cause such extremities. This still goes back to the same thing that keeps popping up which is to resolve one problem by causing another. There needs to be action plans done not only for California but for the rest of the United States. We are consistently pointing the finger of why water is running out but not how to solve it. We are in need of this water for survival, for our crops, for the environment and the other organisms in it. Education needs to be the first thing to show everyone what is happening with pollution, dumping, fracking, and wasting. We can try to restore rivers near by the communities experiencing flood damage or set up water catchments for storm runoff in streets and parking lots. Things taking a bad turn doesn’t always the outcome will be bad. It just means that we need to get a hold on things and make changes. It happened economically for the United States causing attention and now with water.

    1. Dessica H.

      Yes, it seems to me that the government and the EPA need to buckle up and conduct a series of toxic waste assessments on soil and water in and around fracking plants. Leaving the unknown effects of fracking unknown will harm the environment, plants, animals, insects, and most important the water that sustains the environment. The EPA can start by researching the most hazardous chemicals that can be produced by fracking such as possible nitrates, sodium cyanide, ethylene glycol, lead, and radioactive material. Scientists have determined fracking can possibly increase naturally occurring radioactive material such as uranium, radium and radon (1, 2). High levels of naturally occurring radioactive material has toxic effects to the environment, potentially causing cancer in animals and humans (1, 2). Most drilling sites are in impoverished rural areas where accessing healthcare is difficult (1). The toxic effects of fracking can increase health disparities in surrounding communities that are already at a high risk due to poverty and lack of access to healthcare (1).

      1. Finkel, ML., & Hays, JJ. Commentary: Environmental and health impacts of ‘fracking’: why epidemiological studies are necessary. Epidemiol Community Health jech-2015-20548.7 Aug

      2. Brown VJ. Radionuclides in Fracking Wastewater: Managing a Toxic Blend. Environmental Health Perspectives. 2014;122(2):A50-A55.

  3. Feyishayo Dahunsi

    This article highlights the critical endangerment of the world’s most valuable resource, water. With so much little water remaining that is actually accessible it is more important than anytime in human history to wisely use and conserve what we have left. Methods such as fracking are extremely harmful because it not only requires excessive amounts of freshwater but it ends up producing contaminated water and alternating the natural cleansing process of aquifers upon which we rely so heavily for drinking water. It seems that there must be a give and take in this particular situation. Continue to pollute and waste our dwindling water supply for the purpose of acquiring and using up other precious and exhaustible natural resources like oil or natural gas. The other option would be to start conserving our water supply and greatly reduce activities like fracking that damage the environment for the purpose of oil and instead relying on other alternative forms of energy. This can be accomplished with not only more awareness of the issue, but more strict penalties imposed on states who fail to regulate such acts.
    “The industry suggests pollution incidents are the results of bad practice, rather than an inherently risky technique.”(Shukman n.p.) Furthermore, the industries benefiting from fracking practice will be the last ones to admit how harmful their techniques are. Consequently it is really up to the states under the direction of the federal government to more closely examine fracking from the largest corporations to the smallest ones.

    Shukman, David. “What Is Fracking and Why Is It Controversial?” BBC News. BBC, 27 June 2013. Web. 15 Oct. 2015. .

  4. Bart Wilder

    The current water crisis is another problem that demands the full attention of our government. I find it very alarming that there has been several incidents concerning fracking and ground water contamination. The most alarming incident involved the one in California, due to the fact they are in a current drought with water shortages. This is another case, where money and greed trumps the lives of people, and I feel like the big oil companies should be held accountable for their actions, regardless if its a mistake or not. Doctors cannot make mistakes with patients or they could end up being sued or lose their medical license. So why should the big companies go unscathed. Furthermore, I think the EPA should put more policies in place to reduce the over pumping of aquifers. One suggestion, should be that states should be able to share water, when droughts occur, rather than continue to deplete their own water supply while in drought.

  5. Shawn Friedland

    Fracking oil using contaminated water seems unnatural and counterproductive to the global problem we are facing in the world. As someone who just learned about fracking, it amazed me that we are drilling for oil that we do not need and using water that we really do need to get oil out of the ground. Pumping in toxicants and carcinogens in the water used to frack oil just seems so counterproductive to me. I understand it is an easy and accessible way to get oil from underground and oil companies are really taking advantage of fracking in the US, but it is a very short-term, selfish solution for energy that is causing huge problems for communities that live near those fracking sites. They are suffering from contaminated water going into their groundwater, wells, fields and the animals drinking the toxic runoff water from fracking. Most people in urban areas do not realize the devastating effects fracking has on the rural part of the country. People are actually drinking the wastewater produced by fracking and eating crops that were watered in polluted farms, or consuming meat that is contaminated by the water used in fracking and animals drinking the water.

    In all, there needs to be further education and awareness of what is going on. I have not heard the term fracking before reading this. I think most of the US population is in the same situation as me. Further awareness of what is going on with using toxic water for getting oil from underground, wasting our water reserves for getting oil that we do not need and the lobbying being done by oil companies needs to be brought forth and taken seriously by the population and the government. Furthermore, the EPA should have tighter regulations on fracking. With billions of gallons of water being used that are not able to return to the water cycle, we are just adding more insult to injury on our water crisis. Fracking also produces ozone which is detrimental to the environment and people, especially those suffering from asthma.

  6. Karlode Wekulom

    I don’t know the extent at which freshwater is becoming unavailable to California residents; if it’s a state-wide problem or a problem for a few counties. My guess would be problem for a few counties because if it’s a statewide problem, it’ll receive national attention putting California lawmakers on their heels.
    This obviously is not the case on the issue of fracking. Based on my read, officials danced around the “theory” that fracking contaminates groundwater. For example, “We did not find evidence that these mechanisms have led to widespread, systemic impacts on drinking water resources in the United States.”… “We found specific instances when one or more mechanisms led to impacts on drinking water resources, including contamination of drinking water wells.” Statements as such make me feel like politics is in play. It’s also evident in the fact that they don’t make the findings from their research public. What are they hiding? This issue has been going on for a little over 30years and yet we don’t have an answer if fracking contaminates groundwater. As of July 2015 California Council on Science and Technology released a final assessment of fracking in California and concluded that its effects remain “uninvestigated, unmeasured, and unknown. Basic information about how these chemicals would move through the environment does not exist.”
    It’s a shame that people’s lives are being put at risk and nothing is being done about it. Plants and animals will also suffer from the effects of fracking. I recommend these oil companies come-up with a safer method of drilling for oil and gas. Billions of gallons of water are being wasted and toxic chemicals are also put in environment. In my opinion this will have a negative effect to groundwater but I guess lawmaker and officials can’t see that.
    There’s a saying that goes “You don’t know what you have until you lose it”. Hopefully California lawmakers and officials will realize they have a home before groundwater is depleted and the soil becomes infertile. Yet another educating article and definitely a good read.

  7. Beth Stokes

    Fracking has really only been used since the early 80s (1) and has not been around long enough to see the full effects of its use. Further compounding the issue is should fracking be regulated and if so, by whom? While the EPA has been involved with the aftermath of fracking, federal regulation of fracking would prove to be difficult when states have very different opinions on whether or not to allow it. For example Texas has passed legislation PREVENTING moratoriums on fracking while other states have moved to ban the practice entirely (2). Banning fracking shouldn’t necessarily be the issue but regulating the use of the resources and waste products should be. The Clean Water and Safe Drinking Water Acts already act federally to protect water resources but fracking is exempt from many aspects of these laws (3). Not only are millions of gallons of water being used and contaminated in this process, there are many chemicals that are used, many of which are not disclosed to the public (4) and likely federal regulators as well. Then there is the issue of the wastewater generated from fracking. This water is tainted with whatever chemicals were used in the first place and any other contaminants that picked up during the fracking process. The fact that injecting this waste water back in aquifers is the most environmentally friendly option (5) disturbing. I suppose if the aquifer is full enough, adding contaminated water to it isn’t a huge deal. BUT aquifers around the world are not being used in a sustainable fashion and depending on the kinds and amounts of elements and chemicals being injected, this could lead to major environmental and health effects on a global scale.

    Oil companies are promoting fracking as an environmentally friendly method of obtaining methane but in reality, it is not safe for the environment or for the public. There have been numerous reports of health related issues for people living near fracking fields. There are also likely to be numerous health issues we won’t even know about for many generations (6, 7). Until we decrease our reliance on fossil fuel based energy, this is going to continue to be an issue.


  8. AL H

    The human race is in danger! The leaders, the ones in the public eye are only allowing the public to know what they want them to know! RESEARCH is important!

    It is sad to know that the threatened water supply is further threatened through the actions of our leading industries and that the CEO’s of these companies will sell a dream, instead of reality, to the public. If the EPA steps in and regulations are being put into action, there is a reason. Fracking is obviously a problem that is contaminating aquifers and wells and will affect not just us, but our predecessors, as well. I am happy to know that some states are putting laws into place to eliminate this source of water pollution. As I was reading about a study done at Duke, where 68 private drinking water wells in northeastern Pennsylvania and New York were investigated and the methane contamination increased sharply with proximity to natural gas drilling and hydraulic fracturing (“fracking”) sites, the closer the well was to an active drilling site, the more likely the methane was detected 1, I am convinced of the severity of the issues that may be resulting from fracking, including the possibility of ingesting toxic chemicals and other waste materials that will serve transcribe in to a health issue, whether it is long-term or short-term. The ordeal in California last summer is also reassurance that we are harming our water resources and assisting in this steady depletion of water supply. We must protect our water supply and our safety and to do this we need the harmful things, such as, fracking to be under strict regulations, since it is obvious that the leaders in the industries are not to be trusted when it comes to our safety.

    1.Holzman, D.C. “Methane Found in Well Water Near Fracking Sites .” Environ Health Perspect 119.7 (2011).


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