Update II (8:11p.m. EDT; Mar. 15) Here is the latest EPA statement:

From: “Seneca.Roy@epamail.epa.gov” <Seneca.Roy@epamail.epa.gov>
Date: Thu, 15 Mar 2012 15:55:26 -0400
Subject: EPA statement on initial water sampling results in Dimock

On Jan. 19, as a result of requests from residents and a review of the data we had in hand, EPA announced it would perform water sampling at approximately 60 homes in the Carter Road/Meshoppen Creek Road area of Dimock, Pa. to further assess whether any residents are being exposed to hazardous substances that cause health concerns.

The first round of sampling results is now available for the first 11 homes that were tested during the week of Jan. 23. Sampling results from these 11 homes did not show levels of contamination that could present a health concern. Samples from six of the 11 homes did show concentrations of sodium, methane, chromium or bacteria, but concentrations were all within the safe range for drinking water. The sampling results also identified the presence of arsenic at two homes.

Out of the 11 homes tested, there are currently three homes receiving an alternate water supply provided by EPA. EPA will continue to provide water to these homes while we perform additional sampling to ensure that the drinking water quality at these homes remains consistent and acceptable for use over time. EPA is also taking a second round of samples from the two homes where arsenic was detected, and although the levels meet water standards, we will resample to better characterize the water quality of these wells. After receiving results from the second round of sampling, EPA will re-evaluate the need to continue providing an alternate water source.

EPA has offered to meet with all the residents to go over their data and answer any health-related concerns. As further quality assured data becomes available for the remaining homes, we will share with the homeowners in an expedited manner. Our actions will continue to be based on the science and the law as we work to help get a clear picture of water quality for these homes in Dimock.

Roy Seneca
EPA Region 3 Press Officer
Office of Public Affairs
seneca.roy@epa.gov
(215) 814-5567

Update I (6:10p.m. EDT; Mar. 15) The Associated Press reports that the U.S. Environmental Protection Agency today declared that well water testing at 11 homes in Dimock, PA show no signs of contamination from natural gas development. This represents the first release of information associated with testing conducted by the U.S. EPA in Dimock, PA.   More results are expected to be released in the coming weeks.

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We have already raised questions about U.S. EPA’s efforts in Dimock, Pa.  We won’t reiterate those questions but we did take a closer look at the history of contaminants that EPA’s correspondence claimed could be related to natural gas development necessitating continued water deliveries.  To help provide context on elements in the groundwater in northeastern Pennsylvania, and Susquehanna County, it is helpful to review historical facts and reports of groundwater quality by organizations like the U.S. Geological Survey, the Pennsylvania Department of Conservation and Natural Resources and others.

Before we dig into the history, it is helpful to have an understanding of how our nation protects water.  The Safe Drinking Water Act (SDWA) puts standards in place for drinking water contaminants in public water systems, including contaminants in question in Dimock. These are also used as guidance for private drinking water wells. Drinking water standards are the primary mechanisms used in SDWA.  When a contaminant has a primary drinking water standard it is set because it has a “specific” impact on public health.  According to U.S. EPA, a secondary contaminant, is far less severe and is put in place for considerations other than public health:

National Secondary Drinking Water Regulations (NSDWRs or secondary standards) are non-enforceable guidelines regulating contaminants that may cause cosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor, or color) in drinking water. EPA recommends secondary standards to water systems but does not require systems to comply. However, states may choose to adopt them as enforceable standards.”  Pennsylvania has an enforceable standard.

Now on to the data.

Manganese: According to ATSDR, a federal agency charged with preventing harmful exposures and diseases related to toxic substances, manganese is “routinely contained in groundwater”.  According to U.S. EPA’s Drinking Water Health Advisory for manganese:

manganese is an essential nutrient for humans and animals and adults consume between 0.7 and 10.9 mg/day in the diet, with even higher intakes being associated with vegetarian diets.

EPA’s recommends a concentration of manganese in drinking water not to exceed 0.05 mg/L. This recommendation is to avoid staining of clothing and fixtures and is believed to be more than adequate to protect human health.  There is no health based limit.

Manganese was found at .062 mg/l, .66mg/l and 1.36 mg/l in resident 4,6 and 7 respectively.  The EPA memo indicated the resident at well 7 is facing an imminent and substantial health threat.  According to EPA’s advisory for manganese try telling that to a vegetarian who apparently could consume more than 10.9 mg/day.

Arsenic:  ATSDR (page 21) lists arsenic as being abundant in the natural environment and U.S. EPA has indicated “Arsenic tends to occur more frequently in ground water supplies [than public water supplies]”.  EPA has a primary drinking water standard for  arsenic at .010 parts per million (10 parts per billion).  Arsenic was found in one well, Resident 8, at a level of .037 mg/l, above its MCL of .010 mg/l

Arsenic is so common that just due east  in New Jersey samples show its presence exceeding MCL’s in over 30% of private water wells in some municipalities.  Curiously, U.S. EPA is not providing water supplies or usurping state regulatory authorities there to correct this problem.

Sodium: There is no SDWA standard for sodium.  However, EPA has studied the presence of salt in drinking water.  According to U.S. EPA:

sodium posed a unique challenge for the Agency priority setting and contaminant candidate listing process. On one hand, high levels of salt intake may be associated with hypertension in some individuals. On the other hand, sodium levels in drinking water are usually low and unlikely to be a significant contribution to adverse health effects.

EPA faced a dilemma on whether or not to list sodium. A decision not to list would be justified by the fact that much is known about sodium, and it does not appear to be a drinking water risk comparable to other priority contaminants. In fact, this was the logic supporting the decision not to include sodium on the previous drinking water priority list in 1991

According to EPA, in wells for Resident 4 and Resident 6 sodium was found at 82.9 mg/l and 131 mg/l, respectively.  The SDWA secondary standard is 20 mg/l.  Even where EPA found the highest levels of sodium they indicated it “could represent a noteworthy source of intake for individuals on sodium-restricted diets.”  Read: those with high blood pressure, or kidney problems, shouldn’t drink too much of Resident 4 or 6’s water.

So, the question remains how prevalent are these things in northeastern Pennsylvania’s groundwater? And, are there other explanations, outside of natural gas development, as to why these minerals are present in Dimock?

A quick review of data shows manganese is pretty widespread throughout the Commonwealth. According to Penn State University’s “A Quick Guide to Groundwater in Pennsylvania” manganese is the 7^th most frequent pollutant in private groundwater wells present in approximately 6-7% of samples conducted throughout the state. 

 So we know manganese is present in Pennsylvania but a closer look is still needed.  We dug a little deeper and thought we would see if we could find data on its presence in the Catskill Formation (the source of the drinking water wells in Dimock).  Our efforts led us to this Pennsylvania Department of Conservation and Natural Resources report that closely examined several aquifers in the State including the Catskill.  The report found (page 59):

One hundred complete chemical analyses were used to evaluate the quality of water from the Catskill Formation.  The following constituents were found in concentrations exceeding EPA recommended amounts: manganese (25 samples), Iron (14 samples), dissolved solids (4 samples), chloride (2 samples), and Arsenic (1 sample).

On page 55.  “The water is usually of good quality, but high amounts of iron and manganese are a common problem”.

Based on this data alone, it seems clear there is a natural history of manganese in the area. But what about arsenic?  While respected institutions like Dartmouth indicate arsenic is one of the most abundant materials in the earth’s crust, the question remains how prevalent is it in Pennsylvania? This Pennsylvania DEP press release and this USGS report conducted in 2006 help to answer this question.  The USGS report for example,  found Arsenic in 18 out of 143 water wells, representing over 10% of the sample across an eight county region.  Detectable concentrations were found in, you guessed it, the Catskill Formation.  Here 4 wells out of 57 tested had detectable concentrations of arsenic, an even higher rate of detection approaching nearly 15%.  All of these numbers exceed what could be considered a national average of about 7% arsenic contamination in private water wells  according to a comprehensive study by USGS.  To gain a little more clarity a visual representation, like this nationwide, county-by-county, map of the highest naturally occurring concentrations of arsenic, could be helpful.  Pay close attention to northeast Pennsylvania which, you will see, contains a significant concentration of arsenic in groundwater.

Seems that a cursory review of reliable, and historical, data show that manganese and arsenic have been in the groundwater here well before any Marcellus development arrived in the area. This is an unfortunate fact considering Pennsylvania, is one of only two states, that don’t have standards for private water well construction to safeguard homeowners from these naturally occurring contaminants.  We remain unconvinced natural gas development is to blame for two widely dispersed natural contaminants.  Especially considering these materials weren’t used in a single stage of the development process.

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