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Duke study finds radium and elevated salinity in treated oil and gas wastewater; highlights need for revised water quality regulations

The views expressed are those of the author and are not necessarily those of Scientific American.

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Research by Duke scientists finds that oil and gas wastewater contains high levels of radium, bromide, and chlorine 0 even after treatment. Image: Environmental Science & Technology/Warner et. al.

This weekend I spoke with Dr. Avner Vengosh, one of the researchers from Duke University that published results of a study looking at wastewater quality from “fracking” operations in Pennsylvania. Their study, “Impacts of Shale Gas Wastewater Disposal on Water Quality in Western Pennsylvania”, was published this month in the journal Environmental Science & Technology.

The study was widely covered in the news and on various blogs, but there are some nuances that deserve a little more attention. The summary from Bloomberg:

Naturally occurring radiation brought to the surface by gas drillers has been detected in a Pennsylvania creek that flows into the Allegheny River, illustrating the risks of wastewater disposal from the boom in hydraulic fracturing.

Sediment in Blacklick Creek contained radium in concentrations 200 times above normal, or background levels, according to the study, published today in the journal Environmental Science and Technology. The radium, along with salts such as bromide, came from the Josephine Brine Treatment Facility about 45 miles (72 kilometers) east of Pittsburgh, a plant that treats wastewater from oil and gas drilling.

After reading the paper, I came away with three big takeaways:

  1. The research team found evidence of flow back and produced water from Marcellus shale gas operations based on chemicals and isotopic ratios associated with the Marcellus shale. These are the chemical and isotopic ‘fingerprints’ that allowed the scientists to identify Marcellus oil and gas wastewater in the mix of normal wastewater at the Josephine Brine Treatment Facility. The team found elevated levels of chloride and bromide, along with the strontium, oxygen, radium, and hydrogen isotopic compositions. It should be noted that radium (a radioactive element) is found naturally in the Marcellus shale brine and is technically called a NORM: naturally occurring radioactive material.
  2. Wastewater treatment plants are effective at removing 90% of barium and radium such that the effluent is well below the industrial waste discharge limits. The water exiting the wastewater treatment plant (effluent) only has 10% of the radioactive material left in it, which is within allowable limits but still poses a problem (see next point). The discharge limit for radioactive material is 2.2 Bq/l – well above what the team found for 226Ra (0.11 Bq/l-0.19 Bq/l) and for 228Ra (0.04 Bq/l-0.13 Bq/l) – note the volume basis. Also concerning is the highly saline effluent with elevated toxic metals like barium and strontium.
  3. Accumulation of radium in sediment exceeds U.S. regulations as does the solid/sludge precipitate and requires special disposal (cannot dump on soil or in a standard municipal landfill). During the treatment process, chemicals are added to the water to bond with chemicals, which precipitate out. The resulting solid/sludge is then sent for disposal. The Duke team notes that at 900 Bq/kg (note the mass basis), the sludge would need special waste processing. As for the sediment, even though the volumetric amount of radium leaving in the wastewater effluent is within current regulations, it does not remain in the liquid phase and is adsorbed in the river sediment near the discharge site. It then builds up and can be consumed by bottom feeders (and eventually other wildlife) or accumulate in freshwater plants. Sediment samples were recorded at 2,072 Bq/kg (228Ra) and 8,732 Bq/kg (226Ra) – up to 200 times the background levels measured upstream of the treatment facility.

The paper recommends advanced treatment technologies to “prevent discharge of contaminants (Ra and Br) to the environment in areas of shale gas development and hydraulic fracturing”. Dr. Vengosh elaborated (via email):

Our data show that halogens (chloride and bromide are not removed at all) and Ra was removed but not entirely. Removal of halogens would require different treatment technology, such as desalination. The technologies to treat such high level of salinity and radioactivity complex water do exist, the questions are the cost, implementation, and monitoring.

I asked Dr. Vengosh if industrial discharge limits should be revised to anticipate mixing and sedimentation. Here is his answer:

Yes! In our previous study on the impact of effluents from coal ash ponds in NC (Ruhl et al., 2012, see attached) we showed that arsenic is attached to particulate matter and redissolved under reducing conditions at the lake bottom sediments. Thus in spite of the relatively low content of As [arsenic] and Ra [radium] in the effluents their accumulation in river or lake sediments could cause a long-term environmental hazard.

A follow up question from me: “is this unique to this type of stream? Or put another way, with different stream and flow conditions, would the amount of accumulated Ra to be lower and within regulations?”. His reply:

I do not think so, we have results from a pond (not published yet) with similar Ra accumulation results. So radium (and other toxic metals like arsenic in oxic conditions) would tend to be attached to any suspended matter or sediments. The rate of the stream flow might cause a larger and perhaps more diluted zone of Ra accumulation, but the same process is expected.

The major impacts of radium accumulation appear to be localized to less than 200 meters downstream from the treatment facility, and not traveling in significant concentrations downstream and into other watersheds. However, significant amounts of shale-related water is sent through centralized waste treatment facilities and discharged to local streams.

Activities of 228Ra versus 226Ra (Bq/kg) in river sediments collected upstream, adjacent, and downstream of the wastewater discharge site.

These results indicate how quickly the industry has moved relative to the regulatory and scientific communities and the need for stricter regulations based on scientific data. Increased water reuse (or waterless fracking) would address this issue (previous research estimates that 70% of flowback and produced fluids are currently reused in the Marcellus Shale region) as would revised effluent limits for salinity, toxic metals, and naturally occurring radioactive materials.

David Wogan About the Author: An engineer and policy researcher who writes about energy, technology, and policy - and everything in between. Based in Austin, Texas. Comments? Follow on Twitter @davidwogan.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. CherryBombSim 5:25 pm 10/7/2013

    I am pretty sure that fracking companies do not add radium to their fluids (not absolutely sure, but I can think of no plausible reason they would do this), so any radium in the waste is coming from produced water (water that was in the formation originally). Produced water has been coming up oil and gas wells for over a century, so if this is a problem for fracked wells, it is also a problem for the thousands of normal wells that have been drilled.

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  3. 3. sault 5:58 pm 10/7/2013


    While oil and gas drilling waste is an issue for conventional wells, unconventional drilling techniques present different environmental hazzards. “Fracking” requires many times more water than conventional drilling and actually fractures the source rock in the reservoir holding the oil / gas (hence the name “fracking”). Accordingly, a lot more of the material from inside the reservoir comes back up the well instead of mostly the oil and gas itself in conventional drilling. In addition, some compounds that are not soluable in oil or not very mobile in a conventional natural gas reservoir are highly mobile in water, especially the high-pressure water laced with detergents, viscosity-lowering compounds, sand lubricants, etc. that shoots through the rock to fracture it and then shoots back up the well.

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  4. 4. sault 6:13 pm 10/7/2013

    “These results indicate how quickly the industry has moved relative to the regulatory and scientific communities and the need for stricter regulations based on scientific data.”

    This sentence NAILS the core problem that fracking has. Giving any company doing “fracking” activities a special exemption from the Clean Air Act and Clean Water Act was a bad idea in and of itself. But to make things worse, the industry has exploded (sometimes literally!) across the country over the past few years before we figured out how to get the whole process to work safely and cleanly. All the folks who’s well water has turned flammable, smelly, sludge-like or otherwise unpleasant from nearby fracking operations could not get their water tested before the industry moved in. Consequently, the fracking companies have used this fact as a cop-out to avoid accountability on the messes they have made.

    The same principle goes for methane leakage during all the steps of delivering natural gas to the end user, from initial drilling and transport to the residential gas lines that go to millions of homes. We are now figuring out that these methane leaks basically nullify any climate benefits from displacing coal with natural gas for electricity generation. While leak rates vary wildly across the industry, research suggests that a small minority of drillers cause the vast majority of the problem.

    We need to get the regulations back ahead of the industry so that we don’t inadvertantly cause more problems than we’re solving by swithcing to natural gas. Repealing the special exemptions from the Clean Air and Clean Water Acts that fracking companies enjoy would be a good start. We also need a lot more regulators watching over the industry so that a few shady companies can’t get away with cutting corners to get an unfair advantage over their competitors that mostly practice safe drilling techniques. We should never leave an incentive on the table that makes it profitable to pollute the environment and harm people’s health if we can help it.

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  5. 5. Moderate Libertarian 11:04 am 10/8/2013


    “All the folks who’s well water has turned flammable, smelly, sludge-like or otherwise unpleasant from nearby fracking operations could not get their water tested before the industry moved in.”

    Any well contamination that has occurred has been due to poor casing design or materials and not related to hydraulic fracturing itself, which takes place far below (about a mile) water tables. In the valid cases where water well contamination has occurred, due to poor casing, the offending company has settled with the plaintiffs. The flammable water you saw in Gasland is the result of the Weld Country resident sinking his water well into a methane bed. He was trying to get someone to pay for a new well back in the early 1980s when I lived in the neighboring county. He was on the local news.

    The methane emission research to which you refer is based on models that employ arguable default assumptions. The only peer-reviewed study using actual methane measurements found far fewer emissions than what the models predicted.

    While I agree that regulation and enforcement are appropriate, it should be done on the state level where they have boots on the ground and can actually inspect what they are regulating.

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  6. 6. Moderate Libertarian 11:10 am 10/8/2013

    For future articles on potentially controversial topics, I would suggest a more balanced approach, where the author gets more than one opinion on the research. I find too often that popular science publications interview a principle scientist, but don’t include any discussion on the quality of the research. Readers are then left with the impression that the science is “settled.”

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  7. 7. sault 12:36 pm 10/8/2013


    How is poor casing not related to fracking itself? you need to encase the well as a part of the drilling process, right? The fact remains that there are dozens of instances where people’s well water was fine before drilling started and then turned toxic / flammable after gas wells were drilled near them. And all the other wells are basically ticking timebombs because even the best well casing cannot hold its integrity forever.

    As for methane leaks, loss rates of up to 9% were ACTUALLY MEASURED at gas fields in Utah’s Unita Basin, so your belief that this figure was based on modeling is incorrect. The recent study showing lower leak rates (about 1%, or enough to counter 60 – 70% of the climate benefits of switching from coal to natural gas) came from a limited study where the fracking companies knew the scientists were coming and enacted best practices to minimize leaks.

    This feeds exactly into what I was saying. We know how to do fracking much safer and cleaner than what some of the bad actors in the industry practice. If you have a patchwork of 50 different solutions to the same problem, you’ll end up with maybe about 5 – 10 states doing it right and about 30 states that don’t give a crap and let the drillers act like its with wild west out there. The people in Nebraska aren’t magically resistant to Radium and the people in Pennsylvania don’t have some geographic advantage when it comes to tolerating benzene in their drinking water. The industry wants regulation at the state level because its WAY easier to buy off a state government and the patchwork standards that are completely irrational right now only serve to shield the bad actors in the industry from being accountable for their actions. If we had uniform standards across the country and enough federal regulators to enforce them, the industry wouldn’t have to worry about a few bad apples harming people and ruining its reputation.

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  8. 8. sault 12:41 pm 10/8/2013


    What is controversial about the observed evidence shown in this article? If Dr. Vengosh is finding Radium fingerprints of fracking wastewater outside of a water treatment plant, what exactly are you calling into question? With this type of study, either critique his methods or provide another study that refutes his conclusions. Otherwise, there is no room for corporate / political agendas on a science-based website.

    Link to this
  9. 9. mcspencer 10:09 am 10/9/2013

    Thanks for this in depth information. Here’s my take, also published Monday:

    Link to this

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