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.
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