Tuesday, October 25, 2011

Study on Marcellus Drilling Impacts on Drinking Water

Penn State scientists just released a report on water quality in private water wells in rural PA before and after drilling of nearby Marcellus Shale gas wells. Although the study didn’t find significant contamination of drinking water wells, researchers caution that there needs to be more intensive study. 

They also noted unexpected high levels of bromide after drilling, and expressed concern for health impacts. In addition to testing water, the study also documented the enforcement of existing regulations and the extent of voluntary testing by homeowners.

The study, which took place in 2010 and 2011 focused on 233 water wells located in close proximity to Marcellus gas well pads. Phase I of the study (2010) tested 48 water wells within 2500 feet of a well pad both pre- and post-drilling. Phase II tested an additional 185 wells located within 5000 feet of a Marcellus gas well pad post-drilling.

A statistical analysis of pre- and post-drilling water chemistry did not find significant differences due to drilling or hydro-fracking when considering the pollutants “most prominent in drilling waste fluids.” Unlike the Duke study, this study found no significant increase in methane after drilling, and no significant correlations with distance from the well pad.

But, the researchers pointed out, this lack of data could be due to the lack of testing beyond 1000 feet. According to PA law the industry is presumed responsible for pollution of water supplies within 1000 feet of a well pad for six months after drilling. So, few people pay for testing beyond that distance.

One thing the scientists did find was increased levels of bromide in water wells after drilling and/or fracking. “These increases may suggest more subtle impacts to groundwater and the need for more research,” they write. Increased bromide levels were often accompanied by increased levels of sediment and metals in the water. These increased levels were observed within 3000 feet of the gas well pads – suggesting that 3000 feet is a more reasonable distance for testing than the current 1000 feet.

Bromide is rarely tested as part of the industry-sponsored pre-drilling baseline sampling. The PSU researchers selected bromide as a parameter for their study because it is typically not found in detectable concentrations in undisturbed groundwater and because it is found in relatively high concentrations in drilling gas wastes. For those reasons it serves as a good indicator of the influence of gas drilling on groundwater.

In the pre-drilling samples bromide levels were always well below detection levels (0.1 ppm). But in seven wells bromide was detected in measurable concentrations. Those wells were located within 1670 feet of five different Marcellus well pads that were operated by three separate companies.

While bromide does not present a health hazard by itself, it combines with disinfection agents to create a carcinogenic byproduct - and that concerns the researchers. They suggest two potential sources of the bromide: drilling mud and flowback fluids.

You can read more of their findings at


  1. The chemicals that were tested for which did not increase after fracing and are shown in paper (TDS, Cl, Ba, C, & methane) are all found in naturally occurring formation water. Therefore formation waters did not move upward into aquifer.

    Br increased in aquifers after fracking, showing that fracking fluid polluted the aquifer.

    Br in elemental form is not too toxic, but in frack fluids it is part of the biocide, which is toxic in even trace quantaties.

    The industry's base line test of aquifers does not include frack chemicals. It gives only the illusion of safety.

    1. Good work that is needed.

    It would have been good for PSU to document the type of activities that were used by those three companies. This could have generated a better idea of the practice that may have caused the problem. This could have lended support to : liners, closed loop drilling, use of only freshwater while drilling through the freshewater system, self-contained sites, etc. Also there was no comment regarding well location - side slope, upgradient, and/or downgradient.

    b. Why after completing Phase I - and identifing a bromide issue was not this parameter evaluated in Phase II - did i miss something. If the only fingerprint from Phase I was bromide - why not do it in Phase II - and funding is not answer.

    c. Did private well construction play a role?

    d. The actual water quality data for the six wells presented in Figure 9 should be provided.

    e. We recommended bromide monitoring in 2009.

    f. We are working on a state-wide citizen groundwater and surfacewater database - not funded, but a private well owner survey. This study suggest this type of work is needed- please support.

  3. If I understand correctly, Br++ is not present in the driller's mixture of fracking chemicals, but it comes to the surface in the return fluid ('produced water').

    Therefore it can serve as a 'marker', showing migration of material (formerly sequestered deep underground) into shallow formations.

    We have almost *no idea* of everything that might be contained in 'produced water' -- since we can only measure what we're able to test (and take the trouble to test). So, I take the appearance of Br++ as a very ominous sign. We should take no comfort in the finding that 'fracking fluid' hasn't been found; Br++ is a strong warning that 'something is happening' which is beyond our control, and possibly beyond our comprehension.

  4. I am guessing bromide is used in water as a biocide, maybe cement mix, and drilling mud.

    What actually surprises me is the concentration?
    How fast it moved?

    Bromide is more typically found in high concentration saline and brine water.

    If the frac fluid was present more would show up. It would be nice if PSU released the raw data, without names, addresses, etc, but it is confidential. If they released the raw data, it would be possible to at least look at the cation and anion concentration to a good pathway. Also - if the well site was known you could pull the MSDS sheet to look at the chemicals used. Was BioRid used for example?