Related to natural gas development, the most frustrating part of this experience, for me, has been the lack of a fact-based review of the data. That is what you will find here - a fact based review with NO SPIN either way. I try not to make any judgments. The main goal of this evaluation is to understand the nature of the regional water quality and to provide a fact based review of the data. The results are compared to the EPA and Pennsylvania Drinking Water Standards. If no standard was available, we searched for a standard that has been established by another state or the World Health Organization.
First question is why? Because I do not have all the facts for each well for a number of reasons, which include inadequate or no baseline testing and lack of long-term information for each source. I was not on-site or part of the initial baseline testing or investigation, but I was invited on-site to witness the sampling that was conducted by the EPA. Therefore, the following is a review of this single sampling event.
The following is a summary of the water quality data that was generated by the EPA for a private water well identified as HW-8a in Dimock, Pennsylvania. The well was sampled by the EPA, DEP, and the local natural gas development company in 2012 after the natural gas drilling wells had been drilled, developed, installed, and some under production. The primary objective was to determine the presence of any residual impacts at that specific time.
A fact based review - Well by Well of the Available Well Water Data for the Dimock Area that was generated by the EPA. I was not involved with the sampling, but I was on-site during the sampling and field evaluation of one home. I was invited by the homeowner. We are still in the process of reviewing the data. The main goal of this evaluation is to understand the nature of the regional water quality and to provide a fact based review of the data. The results are compared the EPA and Pennsylvania Drinking Water Standards. If no standard was available, we searched for a standard that has been established by another state or the World Health Organization.
1. Without predrilling data, it is not possible to comment on the cause for any water quality problems. This has been a very frustrating issue for this area. In many cases, there was no to very little predrilling baseline testing conducted or the testing was inadequate and had "Zero" follow-up.
2. Where possible, I have noted situations where elevated levels of a water quality parameter exist in Pennsylvania.
3. If duplicate analysis provided, I attempted to use the highest reported value.
4. This evaluation was based on using the 2011 EPA Health Advisory (Source). For a more recent version of the EPA Health Advisory Click Here.
5. This is not about cause and effect; it is about a review of the data.
With the exception of the following parameters, the remaining values were reported as NOT Detected (U)
Total Coliform – (54 colonies per 100 ml – since EPA collected this sample at the end of the purging process – this suggests the well is vulnerable to near surface influence and the presence of total coliform would suggest the water is not potable. This is a very common problem in NEPA and about 30 to 50% of private wells have total coliform bacteria. The problem could be private well construction, type of well cap, or improper well siting. The primary recommendation would be to inspect the well, shock disinfect the well, and retest.
Note: Fecal coliform was negative.
Ethylene glycol – the reported value is < 10 mg/L – there is not standard, but the EPA has a guidance limit of < 7 mg/L. Other states have lower and higher standards:
New Jersey 0.300 mg/L (300 ppb) Arizona 5.5 mg/L (5500 ppb) New Hampshire 7.0 mg/L (7000 ppb) Florida, Massachusetts, and Minnesota14.0 mg/L (14,000 ppb)
At a minimum, I would recommend retesting for ethylene glycol and other glycol compounds using a method that is more sensitive or conducting some type of standard additions analysis.
Chloride – 4.29 mg/L (OK) – drinking water standard is < 250 mg/L – this does not suggest any specific impact.
Sulfate –10.4 mg/L (OK) – drinking water standard is < 250 mg/L – this does not suggest any specific impact.
Aluminum – 0.0375 mg/L (Total) and < 0.030 mg/L (D)- drinking water standard ranges from 0.05 to 0.2 mg/L. This parameter is regulated as a secondary drinking water standard, because of aesthetic reasons. (OK)
Arsenic – < 0.002 mg/L (Total) and < 0.002 mg/L (D) – drinking water standard is < 0.010 mg/L – this does not suggest any specific impact and arsenic is a common problem in NEPA – about 6 % of private wells have arsenic above 0.010 mg/L. This should be monitored annually (OK)
Barium - 0.036 mg/L (Total) and 0.0379 mg/L (D) – drinking water standard is < 2 mg/L – this does not suggest any specific impact and barium is typically detectable in non-saline impacted water at a level of less than 1 mg/L. (OK)
Calcium- 14.4 mg/L (Total) and 14.2 mg/L (D) – no specific drinking water standard, drinking water standard is available. (OK)
Copper – 0.0113 mg/L (Total) and 0.009 mg/L (D)- Copper is regulated as a primary standard (EPA and PA) and secondary drinking water standard in Pennsylvania. Primary standard 1.3 mg/L and secondary standard 1.0 mg/L. (OK)
Lead – 0.0028 mg/L (Total) and 0.0012 mg/L (D)- Lead is regulated as a primary standard (EPA and PA) at 0.015 mg/L, but the action level in PA for source water is 0.005 mg/L. Because of the hits for copper and lead, it is possible that the nuisance bacteria may be causing some corrosion related problems – Call MIC – Microbiologically Induced Corrosion – Problem recommend inspection of the well, camera survey, shock disinfection, and retesting. This is a common problem in NEPA. (Action Needed may be a warning sign of corrosion) - (OK)
Magnesium - 2.79 mg/L (Total) and 2.76 mg/L (D) – no specific drinking water standard, drinking water standard is available. (OK)
Manganese – 0.112 mg/L (Total) and 0.105 mg/L (D) – Manganese is regulated as a secondary drinking water standard in Pennsylvania and the action limit is 0.05 mg/L. Therefore, the total manganese content exceeds the secondary drinking water standard. Since the manganese is in a dissolved form, the water could become browner in color over time. Because the water coming out of the well has dissolved manganese, the water treatment system would require either chemical oxidation or some type of ion exchange system. Elevated level of manganese is a common water quality problem in Northeastern Pennsylvania. Action is Recommended, because of an aesthetic issue and it could be related to Iron-Related Bacteria and MIC.
Sodium – 2.67 mg/L (Total) and 2.60 mg/L (D) – – no specific drinking water standard, drinking water standard is available, but the EPA has added it to the Candidate List to provide more analysis. The EPA’s initial value of 20 mg/L has been clearly identified as not realistic. When chloride (salt is sodium chloride) is present at a concentration of over 250 mg/L, the water can have an “off” taste. At 400+ mg/L chloride, the water will definitely taste salty. (Source- Dr. Brian Redmond, Professional Geologist). (OK)
Zinc – 0.0086 mg/L (Total) and 0.0082mg/L (D) – Zinc is regulated as a secondary drinking water standard by the PADEP in Pennsylvania and the action limit is 5.0 mg/L. (OK)
Ethane – 0.350 mg/L – No specific drinking water standard (OK)
Methane – 9.2 mg/L – No specific drinking water standard, but the level indicates supersaturated conditions. This means the well pump is pulling in water that is not in equilibrium with the atmosphere. The well is above the new action limit of 7 mg/L and methane gas mitigation measures should be employed. These measures not only include venting the well, but also potentially modifying the well, installing treatment, or taking other action.
There are places in PA were baseline levels of methane gas are at or above 7 mg/L. In general, I would estimate that 1 to 3 % of private wells may have elevated levels of methane. In addition to modifying the well, it would be advisable to conduct isotopic analysis. Based on the ratio of methane to ethane, the ratio is 26.2. Since a ratio of methane to ethane of over 1000 typically suggests a biogenic source and a value of under 100 suggests a thermogenic source, the available information would suggest a thermogenic source for the gas. As a guide, it may be possible to use a ratio to suggest the source of the gas- “ if the ratio of methane to ethane is 25, the source is thermogenic, but if the ratio is over 2500, then it is biogenic" (Mr. Bob Pirkle, President of Microseeps, Inc.), but between 25 and 2500 this is where isotopic analysis is critical.
No specific health concern, but a health risk associated with the potential for a flammable environment. Action needed to properly vent gas from the well, perhaps modifying the well, water treatment to reduce methane level in the water to < 7 mg/L or more, and isotopic analysis recommended.
May be advisable to check the level of other gases, such as propane.
Biogenic formation of methane: methane produced by biological activity most typically in anoxic (without oxygen) settings via methanogenic bacteria.
Thermogenic formation of methane: the formation of methane is caused or associated with a chemical reaction combined with heat and pressure without the need for microbes.
There are two main types of methane found in rock formations and groundwater. The types are based on a difference in origin, not composition:
1. Thermogenic methane, which is formed from buried organic matter at considerable depths where the rocks are compressed and heated; this includes the methane found in coal, gas from some Devonian sandstones/shales, and gas from the Marcellus and Utica Formations. Methane is produced by the inorganic breakdown of organic matter (heat and pressure).
2. Microbial (previous term biogenic or bacterial methane) forms closer to the surface by the action of bacteria (**methanogens**- “bacteria that produce methane and cannot live in an environment with oxygen). This would include methane generated in landfills, lake sediments, wetlands/swamps, organic-rich glacial deposits, other recently buried organic deposits, and other carbon rich environments that are without oxygen. Microbial methane gas typically contains 20 percent to 30 percent less methane than is found in thermogenic natural gas.
Total Dissolved Solids – 62 mg/L – Total Dissolved Solids is regulated as a secondary drinking water standard by the PADEP in Pennsylvania and the action limit is 500 mg/L. (OK)
Anthracene the reported level was 0.00006 mg/L (0.06 ug/L). is an unregulated synthetic organic compound and polycyclic aromatic hydrocarbon. PAHs are created when products like coal, oil, gas, and garbage are burned but the burning process is not complete. There is no EPA or PADEP drinking water standard and the primary recommendation would be to retest the water. During retesting, it is critical to check for airborne sources of contamination during sampling. The EPA reports a trigger value of 1.3 mg/L, but I can not find a reference, but I did find a reference to a DWEL of 2.0 mg/L. It appears that the health-based screening requirement in California is 2.0 mg/L and a lifetime exposure limit is 10 mg/L- based on this information (OK).
Butyl benzyl phthalate – the reported level was 0.00011 mg/L – “Benzylbutylphthalate, also called n-butyl benzyl phthalate (BBP) or benzyl butyl phthalate, is a phthalate, anester of phthalic acid, benzyl alcohol and n-butanol.” The health based screening level appears to be 0.100 mg/L and the EPA Human Health Equivalent is 1.4 mg/L. Butyl benzylphthalate is an industrial solvent and additive used in adhesives, vinylflooring, sealants, car-care products and some personal care products. (OK)
4-chlorophenyl phenyl ether was reported at a level of 0.03 ug/L or 0.00003 mg/L. The preliminary research suggests that this chemical has a relatively low solubility and would have a tendency to bind to soil and sediment. In general, it is considered to be insoluble or have a low solubility in water. The U.S. EPA Storet Data Base, 1,333 samples, 1.1% positive, median concentration less than 10 ug/L or 0.010 mg/L. Because of the affinity to have only slight mobility in soil and water and because the well is vulnerable to near surface activity, it may be advisable to check the area around the well for evidence of surface contamination.
4-chlorophenyl phenyl ether is an anthropogenic compound, and is not known to exist in nature.” Florida appears to have established a standard of 0.010 ug/L. Based on the available standard, the level seems appropriate, but it would be advisable to monitor the quality of the water and inspect the area for signs of surface contamination. (OK)
Hexachlorobenzene (HCB) - was reported at 0.07ug/L or 0.00007 mg/L and the reported PADEP/ EPA has a MCL of 0.001 mg/L. (OK) Florida also has a standard of 0.001mg/L. (OK)
di-n-octyl phthalate (DNOP) - the reported value was 0.00008 mg/L and no trigger limit is reported. Exposure to di-n-octylphthalate occurs mainly from eating food or drinking water that is stored in plastic containers. There does not appear to be an action limit, but it would be advisable to monitor and conduct a site-specific survey. “This type of plastic can be used for medical tubing and blood storage bags, wire and cables, carpet back coating, floor tile, and adhesives. It is also used in cosmetics and pesticides.”
Pryene - the reported value was 0.00006 mg/L and the reported trigger limit is 0.087 mg/L. Florida has a health advisory level of 0.210 mg/L for Pryene. (OK)
Acetone - the reported value was 0.0008 mg/L and no trigger limit is reported, but PADEP has a Medium Specific Concentration (MSC) for aquifers with a TDS of < 2500 mg/L of 33.0 mg/L and Massachusetts appears to have a drinking water standard of 6.3 mg/L. (OK)
Nitrate+Nitrite – 0.19 mg/L, the drinking water standard for nitrate is 10 mg/L and nitrite is 1 mg/L. (OK)
a. Methane above the action limit – recommend venting and other modifications to the well and
regular monitoring. Gas appears to have a thermogenic origin and **isotopic** analysis recommended.
b. Retesting for glycol using a more sensitive method.
c. Hits for copper, lead, zinc, and aluminum may suggest corrosive water which is common in
NEPA. These parameters were not above a drinking water standard.
d. The water was positive for total coliform bacteria, water would be classified as not potable.
This would suggest that the well is vulnerable to contamination or impact and that the well could facilitate groundwater contamination. Well system needs to be inspected and possibly repaired.
e. Recommend testing the well water for forever chemicals (PFOA and PFOS).
Again – this is not about cause and effect- it is an honest review of the data. (Period)
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