Study: Leaks from CO2 stored deep underground could contaminate drinking water

“Potentially dangerous uranium and barium increased throughout the entire experiment in some samples.”

DURHAM, N.C.Leaks from carbon dioxide injected deep underground to help fight climate change could bubble up into drinking water aquifers near the surface, driving up levels of contaminants in the water tenfold or more in some places, according to a study by Duke University scientists.

Carbon capture and storage (CCS) from fossil fuel plants has many problems that constrain its ability to be even 10% of the solution to the climate problem (as discussed here).  One of the biggest near-term problems is cost (see Harvard: “Realistic” first-generation CCS costs a whopping $150 per ton of CO2 “” 20 cents per kWh!).

But public acceptance (aka NIMBY) is also a huge problem — one that is likely to grow after the publication of this new study, “Potential Impacts of Leakage from Deep CO2 Geosequestration on Overlying Freshwater Aquifer” (PDF here).

What kind of contaminants could bubble up into drinking water aquifers:  “Potentially dangerous uranium and barium increased throughout the entire experiment in some samples.”

Here’s more of the Duke release on the study that “appears in the online edition of the journal Environmental Science & Technology, at”

Storing carbon dioxide deep below Earth’s surface, a process known as geosequestration, is part of a suite of new carbon capture and storage (CCS) technologies being developed by governments and industries worldwide to reduce the amount of greenhouse gas emissions entering Earth’s atmosphere. The still-evolving technologies are designed to capture and compress CO2, emissions at their source – typically power plants and other industrial facilities – and transport the CO2 to locations where it can be injected far below the Earth’s surface for long-term storage. The U.S. Department of Energy, working with industry and academia, has begun seven regional CCS projects.

“The fear of drinking water contamination from CO2 leaks is one of several sticking points about CCS and has contributed to local opposition to it,” says Jackson, who directs Duke’s Center on Global Change. “We examined the idea that if CO2 leaked out slowly from deep formations, where might it negatively impact freshwater aquifers near the surface, and why.”

Jackson and his colleague Mark G. Little collected core samples from four freshwater aquifers around the nation that overlie potential CCS sites and incubated the samples in their lab at Duke for a year, with CO2 bubbling through them.

After a year’s exposure to the CO2, analysis of the samples showed that “there are a number of potential sites where CO2 leaks drive contaminants up tenfold or more, in some cases to levels above the maximum contaminant loads set by the EPA for potable water,” Jackson explains. Three key factors – solid-phase metal mobility, carbonate buffering capacity and redox state in the overlying freshwater aquifer – were found to influence the risk of drinking water contamination from underground carbon leaks.

The study also identified four markers that scientists can use to test for early warnings of potential carbon dioxide leaks.  “Along with changes in carbonate concentration and acidity of the water, concentrations of manganese, iron and calcium could all be used as geochemical markers of a leak, as their concentration increase within two weeks of exposure to CO2,” Jackson explains.

The study was funded by the Department of Energy’s National Energy Technology Laboratory and Duke’s Center on Global Change.

The release notes:

“Based on incubations of core samples from four drinking water aquifers, we found the potential for contamination is real, but there are ways to avoid or reduce the risk,” says Robert B. Jackson, Nicholas Professor of Global Environmental Change and professor of biology at Duke. “Geologic criteria that we identified can help determine locations around the country that should be monitored or avoided.”

I doubt that monitoring by itself is going to satisfy many local residents — especially with the growing concern about impacts on fresh water from natural gas fracturing.  The fact that you may be able to detect a leak early isn’t the issue — the issue is whether your detection of the leak can lead to actions that would stop the leak, when it might just be too late.

What will need to happen, I think, is to see if there are a set of geological criteria that allow one to minimize or avoid this problem entirely.  This problem may not turn out to be fatal to CCS, but might well limit the places where sequestration is practical — either because the geology is problematic or the site is simply too close to the water supply of a large population.

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27 Responses to Study: Leaks from CO2 stored deep underground could contaminate drinking water

  1. Gord says:

    Has there been any research done on using old oil wells to store CO2?

    They have been sealed up for some time at high pressure.

  2. Doug M. says:

    Gord — I think injecting CO2 into older oil wells is actually a long-established method of extracting the remaining oil. Though I’m not sure how the CO2 injected for this purpose compares to the amount that could possibly be sequestered that way.

  3. David Smith says:

    I was mildly aware of work going on for years at Yucca Flats that was supposed to be the solution to longterm storage of nuclear waste which apparently failed in the eleventh hour and was abandoned. I fear that this will be the fate of CO2 sequestration. Powerful interests are willing this approach to work, not because the technology is reasonable and breakthroughs are near, but because they don’t like other solutions. In the eleventh hour, it too will fail, making the whole effort, in future retrospect, an incredible waste of time and resources that would have been more wisely spent on something else.

  4. cr says:

    OT, from the LAT:

    “Movie review: ‘Cool It’
    Danish academic Bjorn Lomborg’s controversial environmental ideas are explored in Ondi Timoner’s documentary that’s a dose of hope and creativity after the gloom of ‘An Inconvenient Truth.’…

    As the story shifts from Lomborg to the scientists experimenting with ways to offset global warming, we get a look at the possibilities. The range of ideas is eclectic, from the practical simplicity of cooling cities by changing the color of the streets to highly complex systems designed to alter atmospheric conditions. By suggesting there is light at the end of the global warming tunnel, Timoner has made “Cool It” a hopeful film. We just have to know where to look for the switch.”,0,2737605.story

    Nothing in there about how accurate (or inaccurate) this is.

  5. Mike Roddy says:

    People like Koch and Boyce from Peabody know perfectly well that CCS is a mirage, and can’t possibly pencil out. They talk it up strictly as an excuse to make more money for themselves in the next couple of decades. This is psychopathic behavior on their part.

    Notice that whenever they bring it up they skimp on the details. It’s like smokers used to say when I was a kid: “By the time I’m in middle age, they’ll have a cure for cancer”.

  6. Mike Roddy says:

    cr, #4:

    Lomborg is one of the most debunked authors in history. Even his footnote references are fabricated:

    He can sucker journalists and a lot of the unwary public, but to those of us who’ve been following him for a while his latest foray is like the return of a bad dream.

  7. Susan Anderson says:

    A teensy bit OT, but last night’s CSI (Nevada original) had quite a good expose of dangers of fracking in their storyline – rather well done. I heart Lawrence Fishburne.

    I’m afraid the descent into chaos is so disorderly what seems obvious to us is being absorbed piecemeal with almost complete lack of comprehension or sympathy to the disenfranchised, but I applaud the use of an issue like this in a popular TV series.

  8. OMG
    It’s MTBE all over again.

  9. David Stern says:

    It is certainly worth trying CCS as one of many technologies and these kinds of studies are also important, though I am more concerned about the effects of drilling for unconventional gas. Some investments in research and development pay off and some don’t. That’s the nature of the business.

  10. Susan Anderson says:

    For those challenged by acronyms: MTBE

    interesting story

  11. cr says:

    Mike @6

    I know that about Lomborg and you know that and people who pay attention know that. But obviously the LAT doesn’t know that. Having someone with no real background knowledge on him, or scientific knowledge, review that film was very bad. This isn’t Megamind, it’s propaganda.

  12. David B. Benson says:

    CO2 sequestration offshore in mafic rock is probably quite safe; nobody has tried it yet. See for in situ basalt weathering:
    Indeed, on-shore sequestration in ultramatic rock is probably quite safe and an accidental ex situ experiment has been underway for some time:

    Injecting CO2 into petroleum and methane producing formations is sure to work. If the methane, being lighter than CO2, stays underneath the capstone, so will the CO2. Unfortunately there simply isn’t enough of such formations.

    If injecting into ultramafic rock works as well as expected, there in enough exposed in Papua New Guinea alone to premanently remove all the excess CO2 from burning fossil fuels, past, present and future. It might be a bit expensive.

    What one hopes scales up, so is more than a laboratory scale effect, is

  13. David B. Benson says:

    I’m not enough of a geochemist to be sure, but I seriously doubt that supercritical CO2 pumped into deep saline formations will leak upwards at all. The reason that I read about is a slight chemical affinity of the CO2 for the molecules of the rock; there is a small attraction.

    More of a concern for sequestration on land is that the ground will noticably swell, probably a bad effect. To counteract this one needs to pump out a corresponding volume of the brine. That is certainly possible and is down in connection with petroleum recovery; see Bryan Lovell’s Challanged by Carbon: The Oil Industry and Climate Change. The problem then is moving the brine to deep off-shore.

  14. Colorado Bob says:

    Stephen Leahy –
    Here’s the list I started, 10 countries so far –
    Global Reports of the 2010 Coral Bleaching Event

  15. Leland Palmer says:

    Hi All-

    Like it or not, we’re going to have to do CCS in a big way, hopefully carbon negative CCS, if we want to live, IMO.

    Contamination of ground water?

    At least most of us will be alive to drink it, if we use biomass energy plus CCS to slow, stop and reverse global warming.

    Most people who have looked at the issue quantitatively say that absent CCS, costs to get back to 350 ppm rise asymptotically and make it effectively impossible to get there, without BECCS.

  16. Phil says:

    I can’t help but see CCS as yet another example of “tchnofix” magical thinking, alas.

    Any sequestered carbon has to stay put for tens, nay, hundreds of thousands of years.

    Given that, is it unreasonable to ask this question?

    If we want to guarantee that captured carbon stays put for 10,000 years plus, what sort of duration should the pilot programme have?

    A 100 year pilot seems a tad short to me.

    No, I think it is best that we realise NOW that we can’t have our cake and eat it; that the reason why this planet’s biosphere is hospitable to mankind is precisely because natural processes have sequestered a lot of carbon in the form of oil and coal.

    The problem is that we’re hell-bent on unsequestering carbon.

    The solution is to stop doing that.

  17. ToddInNorway says:

    I get the impression that the first reaction of the general public is to REJECT OUTRIGHT ANY project exploiting some aspect of the subsurface using geosciences and engineering which they simply do not understand or have no knowledge thereof.

    This is equivalent to rejecting AGW because we suspect the scientists either do not know what they are doing or are trying to manipulate us.

    Folks there are literally thousands of researchers around the globe working on the challenge and opportunity of CO2 underground disposal. The consensus is clear. There are good sites and there are bad sites. The key to success is to find the good sites and manage them properly. This is the case for shale gas, it is the case for geothermal wells, it is the case for underground waste disposal, it is the case for underground compressed air energy storage, it is the case for seasonal storage of natural gas in underground formations, it is the case for underground oil stores for emergency use, it is the case for long-term disposal of radioactive waste, it is the case of choosing a site for a tunnel, etc.Having said that, I respect that there are many very compelling reasons to not use CO2 capture and storage (CCS) for coal power. But the reasons to reject CCS for coal do not apply to the decision for CCS for natural gas power plants, or for biomass power plants, or for CCS applied to industrial ethanol plants. Indeed if we have a viable way to remove CO2 directly from the atmosphere, it could stored in the underground (where damn near all the carbon came from to begin with)and we might even be able to reverse the atmospheric and oceanic mess we are in.
    The main evidence that CO2 can be stored for millions of years is in the geological record collected at millions of wellbores around the world drilling miles in the underground. We know that there are sites where hydrocarbons have been trapped in underground formations for geologic time (millions of years), so the key is to understand how this came to be and apply those lessons in the appropriate way for any deep subsurface engineered storage project.

  18. Edward says:

    CO2 in water changes the solubility of other substances. Pressure also changes solubility, and not in the way that you would think. There is even a circumstance in which gold becomes soluble, involving temperature, pressure and CO2.

  19. Edward says:

    I just received and read the second draft of Barton Paul Levenson’s paper “Preliminary Analysis of a Global Drought Time Series” to be published in the Journal of Climate. The bottom line is that under BAU [Business As Usual] agriculture [and civilization] crash some time between 2050 and 2055.
    The confirming paper is available at:
    “Drought under global warming: a review” by Aiguo Dai

    It is only 40 years until 2050. It won’t do any good to start doing something in 2049. We must shut down the coal industry completely by the end of 2015. We have to go with technology we already have.

  20. Aaron Lewis says:

    In this instance, CO2 is a waste.

    “End of pipe” waste storage or treatment never works. CERCLA taught us that.

    Pollution prevention and waste minimization is always cheaper. Always!

  21. Lewis C says:

    The idea that CCS can address even 10% of global CO2 emissions was highly questionable before this finding that it could destroy the potable water aquifers that are among the most fundamental of society’s capital resources.

    This finding exacerbates the cost issue (cited at 20c/kwh):-
    by intensifying community resistance (aka Nimby) and significantly extending average pipeline requirements;
    and thus by increasing the ‘bottleneck’ issue of trying to provide infrastructure with capacity for a daily volume of CO2 equal to that of the entire global oil production (whose infrastructure has required over nine decades of highly profitable investment).

    Moreover, by raising coal usage around 30% per kwh yield CCS not only raises similar massive bottleneck issues for additional mining and transport, but also it greatly advances the date of ‘Peak Coal’ with resulting fuel price hikes and intensifying scarcity.

    [It maybe needs saying here that Peak Coal is no benefit at all to climate: it is roughly the halfway point of coal reserves’ extraction].

    I’m interested in just why governments are pouring billions into CCS research when its non-viability, even for 10% of the CO2 fraction of the GHG problem, is becoming so patently obvious. Several motivations are likely in play in varying combinations, including:-

    1/. Disinformation – if govt.s can’t say how coal power emissions will be sequestered, either their energy supply promises are nonsense, or their climate action promises are nonsense, or both.

    2/. Engagement – if govt.s can offer plausible clean coal to the coal lobby, with additional tonnage prospects, that lobby might be persuaded to stop obstructing climate action.

    3/. Moratorium – if govt.s can provide a plausible case for CCS and engage the coal lobby with its deployment, it becomes far easier to legislate that no new coal plants will be built without it (as in UK), and that old plants must retro-fit or close by a given date.

    If anyone has spotted other possible motivations (beside straight greenwash corruption) I’d be very interested to see them.



  22. i agree with David Smith point of view.
    reading through the release note makes me shiver for what the future could hold. i expressly quote it here:

    “Based on incubations of core samples from four drinking water aquifers, we found the potential for contamination is real…..

    why cant folks harness solar energy advantages that we are naturally endowed with. Do i have your vote?

  23. is it worth trying, i naturally ask?
    Most of the supposed technological fixes are bringing on more concerns than the problems they are out to solve. Take the issue of power for an example. Apart from the more renewable energy sources that are gaining slight momentum, we have naturally bedeviled our continents with nuclear wastes and other choices. if we consider solar energy advantages and leverage on the God-given, free-to-own solar power, we can save our climate and ourselves a lot

  24. ToddInNorway says:

    Hi Lewis C #21, CCS could be applied to biomass-fired power plants, thereby achieving a net removal of CO2 from the atmosphere. This is not geo-engineering in the sense of the various science fiction concepts on the table. Net removal of CO2 from the atmosphere will be needed to achieve the 350 ppm target. Because it looks like vast area of forests are essentially doomed to death in the next 10 years and cannot be saved, we could choose to use them for biomass-fired power with CCS and hopefully replace them in areas where forests have a chance to survive in the next 100 years.

    I do agree that CCS for coal is green-washing deception and technically-speaking a complete non-starter.

  25. Lewis C says:

    Todd at #22 –

    I’d agree that CCS could be applied to CO2 from biomass combustion, but I’ve yet to see how it would work financially. At what point will we see a carbon price on fossil fuels high enough to offset the projected $150/TC sequestered ?

    This ‘BECCS’ use of biomass also overlooks the opportunity costs of other approaches – most notably of biochar with its multiple benefits for both climate and agriculture and native forestry, with a substantial fraction of the wood feedstock’s potential energy being collected during pyrolisis to yield a wide range of fuels, plus energy and surplus heat.

    From this perspective it’s notable that it is the carbon fraction of biomass energy feedstock that entails the untenable cost of CCS, not the hydrogen fraction. Thus if the majority of the carbon is sequestered via the profitable sale of biochar, while remaining hydrocarbons are processed and profitably sold as fuels or power, then the entire operation moves from raised costs for carbon-negative biomass energy to raised profits for the same, as well as generating raised agricultural yields. These factors could massively accelerate its deployment worldwide.

    This is of course geoengineering via the ‘carbon recovery’ option, and needs to be actively welcomed as such. Its proper goal IMHO is surely 275ppmv rather than 350ppmv, given that the potentially ruinous Peat > DOC > CO2 feedback was first observed globally around ’61, when CO2 was around 315ppmv.

    I would entirely agree, with deep regret and implacable anger toward the profiteers responsible, that diseased, infested, poisoned and drought-killed trees should be harvested for energy & biochar asap after they’re identified.
    Failure to do so only allows pathogens and super-intense wildfires to spread into healthier forests, as well as ensuring that the identified trees’ unharvested carbon is released as CO2 and CH4 either by rot or combustion.

    To what extent replanting in situ will prove viable may well be a matter of local trial and error, since the climate will become increasingly unstable in the coming decades if no effective albido restoration techniques are accredited for global deployment.



  26. ToddInNorway says:

    Hi again Lewis C #25, thanks for the info. The eminent death of forests is truly shocking, saddening and ultimately results in unavoidable apocolyptic forest fires and subsequent environmental cataclysm. Maybe the site of a giant fire front at 1000 degrees celcius at a forest fire nearby would motivate more general public concern about AGW and ozone pollution.

    I know very little about biochar. My first thought is that any forest not anywhere close to a potential CO2 storage site and in danger of chronic disease, death and forest fire should be harvested using a biochar process. Otherwise I am not sure what would favor biochar over CCS+biomass in cases near attractive CO2 storage sites. My preference for CO2 storage is offshore in deep sub-seabed formations, where there are usually no fresh water resources.

  27. David B. Benson says:

    Here is an interview with a geologist who views sequestering CO2 in deep saline formations as presenting little risk of groundwater contamination. Despite Der Spegels opening editorializing, the geologist offers no opinion on nuclear power or its safety/risks.

    CCS Is One of the Few Options to Minimize CO2 Emissions:,1518,729388,00.html