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-12 in Dimock, Pennsylvania. The well was sampled by the EPA, DEP, and the local natural gas development company in January 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)
Chloride – 3.64 mg/L (OK) – drinking water standard is < 250 mg/L – this does not suggest any specific impact.
Sulfate – 5.20 mg/L (OK) – drinking water standard is < 250 mg/L – this does not suggest any specific impact.
Arsenic – 0.006 mg/L (Total) and 0.0058 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. It would be advisable to monitor the arsenic level of the well on an annual basis.
Barium - 0.707 mg/L (Total) and 0.716 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)
Boron – 0.0538 mg/L (Total) and 0.0522 mg/L (D) – no specific drinking water standard, drinking water standard is available. EPA appears to have a long-term health advisory of 2.0 mg/L, but other states have limits that range from 0.6 to 1 mg/L. Minnesota is the state with the lowest standard of 0.600 mg/L. Therefore, this does not appear to suggest any form of impact. (OK)
Calcium- 28.5 mg/L (Total) and 28.1 mg/L (D) – no specific drinking water standard, drinking water standard is available. (OK)
Iron – 1.24 mg/L (Total) and < 0.1 mg/L (D) – Iron is regulated as a secondary drinking water standard in Pennsylvania and the action limit is 0.3 mg/L. Therefore, the total iron content exceeds the secondary drinking water standard. Since the total value exceeds the limit and not the dissolved, this suggests that the primary recommendation would be to install a water treatment system to filter the iron colloids or particles from the water. The water probably has a reddish or brown appearance. Elevated level of iron is a common water quality problem in Northeastern Pennsylvania. Action is Recommended because of an aesthetic issue.
Magnesium- 4.77 mg/L (Total) and 4.67 mg/L (D) – no specific drinking water standard, drinking water standard is available. (OK)
Manganese – 0.12 mg/L (Total) and 0.139 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.
Nickel - 0.0012 mg/L (Total) and 0.001 mg/L (D) – no specific drinking water standard, drinking water standard is available, but the EPA has suggest a MCL of 0.1 mg/L. (OK)
Sodium – 19.3 mg/L (Total) and 19.3 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)
Strontium – 0.629 mg/L (Total) and 0.618 mg/L (D) – no specific drinking water standard, drinking water standard is available, but it is on the EPA Candidate List. The EPA recommends that drinking water levels of nonradioactive strontium should not be more than 4 mg/L. The report limit is consistent with background levels in Northeastern Pennsylvania. If the background level was above 4 mg/L, it would be advisable to test for radiological parameters, especially alpha/beta. (OK)
Uranium – 0.0018 mg/L (Total) and 0.0016 mg/L (D) – Uranium is regulated as a primary drinking water standard by the EPA and PADEP in Pennsylvania and the action limit is 0.030 mg/L. (OK)
Zinc – 0.0054 mg/L (Total) and < 0.002 mg/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 – 2.00 mg/L – No specific drinking water standard (OK)
Methane – 52 mg/L (supersaturated)– 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. (Action Needed)
Based on the ratio of methane to ethane, the ratio is 26. Since a ratio of methane to ethane of over 1000 typically suggests a biogenic source and a value of under 100 suggests athermogenic 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.
Total Dissolved Solids – 67 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)
Chloroethane – 0.0002 mg/L – there does not appear to be a drinking water standard and the primary route of entry into the body is inhalation. You can smell chloroethane at a level of 0.02 mg/L in water. “In groundwater, chloroethane changes slowly to ethanol and a chloride saltas a result of reaction with water and chloroethane can be formed through chlorination.” There does not appear to be an aesthetic issue, but additional monitoring would be advisable. No specific health concern, but monitoring recommended.
Methyl Chloride (Chloromethane)– 0.0006 mg/L – there does not appear to be a drinking water standard that is regulated by the EPA or PADEP. It appears that water companies throughout the country have reported detection of chloromethane in the water. It appears the EPA has provided a recommended lifetime health based exposure risk non-cancer for chloromethane of 0.030 mg/L. “ Most (99%) of the chloromethane in the environment comes from natural sources.” (OK)
Bromide – < 0.5 mg/L, In freshwater, bromide is typically less than 0.05 mg/L. Therefore, it would be advisable to retest using a method with a lower detection limit. If an ozone-based water treatment system is proposed, it may be best to have the bromide level of less than 0.0063 mg/L to prevent the formation of bromates. Additional Sampling at a lower detection limit – no health concern (OK).
Additional Comments Lithium - was reported at < 200 ppb or 0.2 mg/L. There are nocurrent federal standards for lithium in drinking water. To protect human health, EPA estimated that a lithium concentration in a potable water supply should not exceed 700 μg/l or 0.7 mg/L.
1. No major problems
2. Manganese and Iron were above the secondary drinking water limit and there may be a concern about the presence of nuisance bacteria. Action was recommended.
3. Arsenic detected at a level that was just the drinking water standard in Pennsylvania. It is possible that a treatment system to reduce iron and manganese may also indirectly reduce arsenic. Retest after installing treatment system.
4. Methane - The water is supersaturated and poses a hazard. **Action Needed**. Methane gas appears to have a thermogenic origin.
There are two main types of methane found in rock formations and groundwater. The types are based on a difference in origin, not composition:
a. 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).
b. 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.
5. Ethylene Glycol - the testing was not sensitive enough - recommended retesting using a more sensitive method, i.e., a low level of detection or using a different method.
6. Recommend testing the well water for forever chemicals (PFOA and PFOS).
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