Last Wednesday, July 25th 2012 the U.S. Environmental Protection Agency announced that it has completed its sampling of private drinking water wells in Dimock, Pa. Based on the outcome of that sampling, EPA has determined that the levels of contaminants present do not require additional action by the Agency, the water with the existing private well treatment systems is safe to drink. Regional Administrator, Shawn M. Garvin, said “The sampling and an evaluation of the particular circumstances at each home did not indicate levels of contaminants that would give EPA reason to take further action. Throughout EPA's work in Dimock, the Agency has used the best available scientific data to provide clarity to Dimock residents and address their concerns about the safety of their drinking water.” The EPA’s news release is intended to end the story of Dimock, but bureaucratic speak is never really clear. So, let’s see if we can bring clarity and accuracy to the end of the story of Dimock, PA.
The Safe Drinking Water Act, SDWA, which is how the EPA looks at water quality, defines a contaminant as “any physical, chemical, biological, or radiological substance or matter in water” (U.S. Code, 2002; 40 CFR 141.2). This is a very broad definition of contaminant includes every substance (including minerals) that may be found dissolved or suspended in water, everything but the water molecule itself. However, the SDWA only has MCLs and secondary standards for 91 contaminants. Groundwater aquifers are potentially vulnerable to a wide range of man-made and naturally occurring contaminants, including many that are not regulated in drinking water under the SDWA. The presence of a contaminant in water does not necessarily mean that there is a human-health concern. Whether a particular contaminant in water is potentially harmful to human health depends on the contaminant’s toxicity and concentration as well as other factors including the susceptibility of individuals, amount of water consumed, and duration of exposure. EPA did a final round of testing of the private wells in the Dimock area to make sure that the water from the drinking water wells was safe to consume and all identified contaminants were within the acceptable level as determined by a risk analysis. Most private well owners rarely test their well water quality and very few ever consider testing for the entire suit of contaminants regulated under the SDWA let alone the list of potential contaminants that EPA tested for here.
Dimock, Pennsylvania is located in Susquehanna County near the New York border, overlies the Marcellus Shale and was an early area that had been developed with hydraulic fracturing or fracking. Dimock had been made famous for its appearance in the Josh Fox movie Gasland. In Dimock, Mr. Fox met families who demonstrated on camera how they were able to light their running tap water on fire due to the methane gas present in their wells. That was a rather spectacular display. Residents also claimed to be suffering from numerous health issues related to contamination of their well water. Methane is a simple asphyxiant that displaces oxygen from air. Methane released from water into an enclosed environment could cause serious symptoms. Exposure to low oxygen environments produces symptoms of central nervous depression, including nausea, headache, dizziness, confusion, fatigue and weakness. Even if there was no other contaminant of concern present in the water, the symptoms of central nervous depression could be very frightening.
Cabot began natural gas fracking in the Dimock area in 2008. On January 1, 2009, an explosion was reported in an outside, below-grade water well pit at a home located in Dimock. In Pennsylvania private drinking water wells are not regulated and are often the shallow, dug wells that are housed in a pit. The Pennsylvania Department of Environmental Protection (PADEP) collected samples from wells that provide drinking water to 13 homes located near the Cabot fracked gas wells, and these samples contained elevated levels of dissolved methane gas. (During the year the number of impacted homes would expand to 18 from 13.) The presence of dissolved methane and/or combustible gas was noted in the private wells within six months of completion of drilling of the Cabot gas Wells and Cabot was presumed to be responsible for the pollution, pursuant to Section 208(c) of the PA Oil and Gas Act, 58 P.S. §601.208(c). None of the homes dependent on their private drinking water well had done any extensive testing of their water quality before Cabot began fracking in the area and all contaminants found (except for fecal coliform) are sometimes naturally present in groundwater. The two important questions raised were is the water safe to drink and did Cabot cause any change in the water quality by fracking in Dimock. PADEP presumed Cabot responsible and cited them for improper or insufficient cementing of the well casings. In addition there had been several other violations for improper storage of drilling mud, diesel spills, failure to maintain records and driller’s logs.
In November 2009 the PADEP entered into a consent agreement with Cabot for methane and metals removal systems for eighteen private wells in the Dimock area. The agreement was later revised several times. The revised agreement required Cabot to pay the impacted families settlements worth twice their property assessed values, deposit the money into an escrow account and notify the residents that the money was available and to install a water treatment system (a filter or ion exchange system) in each impacted home. The agreement calls for each well owner to enter into the agreement with Cabot who was to install water treatment systems in their homes. Until the treatment systems were installed, Cabot was to provide delivered bottled water. There were no plans for confirmation testing to demonstrate the effectiveness of the filtration systems. There were eighteen private wells that were part of the PADEP /Cabot agreement. By 2011 only six well owners had signed agreements and had water treatment systems installed in their homes. However, most of these were buying bottled water because they did not feel confident that the treatment systems were effective. Water treatment systems are often simple and unimpressive in appearance and verification sampling should have been performed. Twelve of the private well owners had not signed the agreement Cabot and instead eleven (I could not trace the 12th ) had filed a civil suit against the company. These owners were being provided delivered water by Cabot. On November 30, 2011, with the approval of the PADEP, Cabot ceased delivering water to these homes. PADEP agreed to stopping the water deliveries because there had been sufficient time for residents to sign the agreement and that a remedy for private well owners had been provided. Clearly, many of the homeowners were not satisfied with the remedy offered.
Very public protests took place aided by environmental groups and anti-fracking grass roots groups and resulted in the EPA stepping in and reviewing all the data for the 18 wells. In their summery EPA notes that based on the maximum contaminant sampling results for the 18 wells sampled, levels of coliform bacteria, methane, ethylene glycol, bis (2-ethylhexyl) phthalate (DEHP), 2-methoxyethanoI aluminum were present. Coliform bacteria were found in half the wells and typically indicate a pathway exists for disease causing bacteria to contaminant the water supply, though it . E. coli bacteria and fecal bacteria are a subset of coliform bacteria that only occur in animal and human waste and are a threat to human health. The level of coliform bacteria found in two of the wells was too high to measure. After reviewing all the sample data, information and residents’ concerns by the EPA and ATSDR (a part of the U.S. Department ofHealth and Human Services) the regulators identified a significant group of private wells in the nearby area that had not been tested and were not part of the existing PADEP /Cabot agreement. In addition, the level of concern and frustration of the residents who were party to the PADEP /Cabot agreement prompted EPA to temporarily supply water to four homes and perform follow up environmental monitoring and water sampling and have ATSDR perform a full public health evaluation on the data from the site area. Because many of these compounds affect the same organ systems, ATSDR used suitable methods to evaluate the potential for synergistic actions and the cumulative concentration of all substances, and dissolved combustible gases was considered to protect against the buildup of explosive gases in all wells in the area.
Between January and March of 2012 EPA collected 61 separate groundwater samples, 6 duplicates for quality control testing and performed188 analyses for each sample, in some instances the samples were filtered and retested. These samples covered the water supply to 64 homes, and two rounds of sampling at four wells where EPA was delivering temporary water supplies because prior sampling data found elevated levels of contaminants in those wells. EPA found an elevated level of manganese in untreated well water at one of the wells. Two homes that obtain their water from that well have water treatment systems that can reduce manganese to levels that according to the EPA do not present a health concern.
Many of the perceived problems with well water are caused by the presence of iron and manganese. Iron and manganese can give water an unpleasant taste, odor and color. Manganese causes brownish-black stains on household items washed with the water. In addition, water contaminated with iron and manganese often contains iron or manganese bacteria which feed on the minerals. These bacteria do not cause health problems, but can form a reddish brown or brownish black slime in toilet tanks and clog filters. Iron and manganese often occur together and are naturally occurring elements commonly found in groundwater in many parts of the country. At levels naturally present in groundwater iron and manganese do not usually present a health hazard. However, their presence in well water can cause unpleasant taste, staining and accumulation of mineral solids that can clog water treatment equipment and plumbing. In addition, a persistent coliform (non-fecal) bacteria problem may be caused by iron bacteria. Under guidelines for public water supplies set by EPA, iron and manganese are considered secondary contaminants. The standard Secondary Maximum Contaminant Level (SMCL) for iron is 0.3 milligrams per liter (mg/L or ppm) and 0.05 mg/L for manganese. This level of iron and manganese are easily detected by taste, smell or appearance and thumbing through the results of the EPA sampling I saw manganese levels high enough to see and taste in drinking water.
In addition, to the elevated manganese, there were elevated levels of sodium not beyond what can occur naturally, elevated levels of arsenic not beyond what can naturally occur, but in at least one case significantly elevated over the other samples and above the SDWA MCL. Methane was present in several samples and can also be naturally occurring. Fecal coiform bacteria indicative of contamination from a septic system was present in one sample (that water is NOT safe) and coliform bacteria was present in several samples. Only one of their sodium levels was higher than mine which is naturally occurring, safe to drink and tastes good.
ATSDR performed the risk analysis on the results. Overall during the sampling in Dimock, EPA found elevated arsenic, barium or manganese, all of which are also naturally occurring substances, in well water at five homes at levels that could present a health concern according to ATSDR. In all cases the private wells either now have or will have their own treatment systems that can reduce concentrations of those metals to acceptable levels at the tap. EPA provided all the residents their sampling results and has no further plans to conduct additional drinking water sampling in Dimock or continue to provide drinking water. The water supply to these homes with their treatment systems is deemed to be safe by the EPA.
The bottom line is we really do not know definitively what impact if any Cabot caused to the groundwater. Cabot agreed that they failed to properly grout the gas wells and certainly they did not properly store and contain the fracking fluid. Publicized photos show jugs of dirty looking water reportedly from wells in the area and could be manganese and iron, fecal contamination, or dirt that entered the groundwater through surface infiltration of loosening of fines within the aquifer. EPA sampling is silent on water appearance. PADEP concluded that surface spills and shoddy construction practices by Cabot allowed natural gas from a shallow deposit above the Marcellus to drift into the drinking-water wells of residents. The non-quantified traces of chemicals that are sometimes used in fracking, and antifreeze and are common in fuel that had been reported in previous sampling were not found the EPA water samples. EPA found only naturally occurring heavy metals at levels of any concern.
For the past decade and a half, the US Geological Survey, USGS, has been studying groundwater quality in the United States. The presence of a contaminant in water does not necessarily mean that there is a human-health concern. Whether a particular contaminant in water is potentially harmful to human health depends on the contaminant’s toxicity and concentration in drinking water. Other factors include the susceptibility of individuals, amount of water consumed, and duration of exposure that is why the ATSDR performed their risk analysis. In their survey testing of groundwater in the United States the USGS has found most man-made contaminants at both trace and concentrations exceeding human health screening levels or MCLs in groundwater samples from unconfined aquifers. These man-made contaminants originate at the surface and the unconsolidated aquifers provided little natural protection from surface infiltration.
The shallow drinking water wells in Dimock make them particularly susceptible to contamination. The residents of Dimock did not regularly test their water quality historically. The bacterial concentrations found in early rounds of testing were troubling, though unlikely to have been caused by the fracking, but were indicative of susceptible and potentially poorly maintained or constructed wells. The fecal bacteria found in one well was a health hazard very unlikely to have been caused by fracking, but likely to be caused by a failing septic system. Prior studies of private well water in Pennsylvania have found that approximately one third of private wells test positive for total coliform bacteria (Swistock et al 2009). The highest incidence of coliform bacteria tends to occur with snow melts and rains that carry the bacteria from the surface, but can also occur with iron and manganese. Regularly testing your drinking water and maintaining any water treatment system in your home is an essential part of private well ownership.