The increased production of shale gases nationwide has often resulted in complaints by homeowners in some areas that their drinking water wells have been contaminated by nearby hydraulic fracturing activity. As regular readers of this blog know, I have been reviewing the recently released studies by the Environmental Protection Agency (EPA) which attempt to determine in four different areas of the country whether hydraulic fracturing for oil and gas (hydrofracturing or fracking for short) has been the cause of water well contamination. This blog post reviews the EPA’s “Retrospective Case Study in Wise County, Texas: Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources.”

Northern Texas and southern Oklahoma have had traditional oil and gas development areas for nearly a hundred years. Hydraulic fracturing of the Barnett Shale in these areas has brought a boom of new gas development. Hydraulic fracturing started in the Barnett Shale earlier than in most other areas where shale gas formations are located and it really ramped up around the middle part of the last decade.

The EPA selected Wise County in northern Texas for one of their “retrospective” studies. EPA calls them “retrospective” because they are trying to determine, after the fact, whether hydrofracturing activities caused water well contamination. A herculean feat, since there is usually a lack of data on the groundwater in the areas being studied before hydraulic fracturing took place. There were complaints in three different locations in Wise County of drinking water contamination after hydrofracturing. Wise County is just north of Dallas/Fort Worth. Having spent some time in Texas, the area is what I think most people imagine a Texas landscape to look like – flat with lots of cows and lots of oil wells. It is a pretty rural place and most people depend on groundwater for water supply. They have an excellent aquifer in this area of Texas. It is called the Trinity Aquifer and it is kind of famous among us water folk. It is a prolific aquifer producing large quantities of fresh to slightly salty water. It’s used not only for private wells but for municipal wells and industrial wells too. It has been extremely over pumped and the water table has been lowered pretty seriously. In Wise County the Trinity Aquifer is about 700 to 1000 feet below the surface, while the Barnett Shale is 7000 to 8000 feet below the surface – quite a distance between the two.

One of the three areas where there were complaints of water well contamination was near a small lake next to a gas well pad where a fish kill had occurred. The complaint was a concern with the odor and taste of the water. Two other areas had complaints of odor and corrosion of appliances. One of those two areas also had complaints of the water tasting salty. To determine if there had been an impact on the wells, EPA had to rely pretty much on old fashioned water quality work. The reason was that in testing the water wells for organic chemicals used in hydrofracturing there were no contaminants EPA could link back to the shale gas development, nor was there enough methane gas in the water wells to even analyze to determine whether its isotopic signature for the constituents of methane (Hydrogen and Carbon) were similar to that of the Barnett Shale. Methane can form in groundwater from natural bacteria decomposing organic material and the very low methane levels seen in the water wells tested in Wise County were the same as wells in the Trinity aquifer elsewhere. EPA considered the methane in the Wise County wells as normal for the area and not an indication of contamination from methane in the deeper gas formation.

As I’ve explained in previous posts, scientists can use the ratios of different isotopes of an element to determine how and where the isotope originated. For this study, EPA looked at the isotopic signatures for the isotopes of water – hydrogen and oxygen – and strontium. Of the 16 water wells EPA sampled in Wise County, 13 had the same isotopic signature for hydrogen, oxygen and strontium as that generally found in the Trinity aquifer, but 3 wells in one location were significantly different. In fact these 3 wells became really the source of EPA’s interest. Two of these wells were from the location where homeowners complained of a salty taste to the water. The other well tested was a water supply well in the same area. The supply well was not just drilled into the Trinity aquifer but had been left open in rock formations above the Trinity to draw as much water from various aquifers large and small in order to provide a substantial amount of water. When EPA started their water quality parameter investigation of these three wells, they found water in the two homeowner wells to be different from the water in the supply well.

The water types in most of the wells in all three locations with groundwater complaints were either a sodium bicarbonate or calcium bicarbonate, except in the location with the three wells that EPA was now beginning to consider impacted; there about 20 % of the water type was sodium chloride type water. We know sodium chloride as salt. Hence the salty taste. EPA was able to assemble a number of historical water datasets from the area. EPA also looked at the current water quality in other wells in the area to determine background. When scientists talk about background for water, they are referring to the regular, run of the mill, day to day water quality for groundwater in an area. In other words they are looking to establish the waters present natural chemical composition.

The water from the two potentially impacted homeowner wells had significantly different pH and specific conductance from the historical water data. Specific conductance is a measurement of water’s ability to conduct an electric current. High specific conductance means there are a lot of ions in the water. A lot of ions basically mean there are a lot of dissolved solids in the water. The two wells had higher chloride, bromide, sulfate, potassium, magnesium, sodium, strontium, barium, and boron than historical water data. You get the picture. EPA was now beginning to think that the two homeowner wells had been impacted by brine.  Although the supply well was different in some aspects from background, it was not similar to the water quality issues that the two homeowner wells had.

EPA then looked around for the possible cause of brine intruding into these two homeowner wells. They noted a lot of possibilities, but whittled them down to brine from the Barnett shale or another deep formation coming up through either natural fissures in rock, a historic well or maybe a new well that wasn’t cased properly; leaks from surface impoundments being used to store formation water from the Barnett shale or reserve pits being used to hold cuttings from the borehole of a gas well; a nearby injection well for disposing of brines from the Barnett shale which are brought up during drilling and production; or leachate from a closed landfill within a mile of the wells.

In determining the source, EPA looked at various ratios of one constituent to another. These ratio comparisons have been developed by various researchers to determine if there has been brine entry into a freshwater aquifer. Yes there have been years of studies by those crazy water scientists looking at ratios of the amount of chlorides over the sum of anions in water compared to total dissolved solids; ratios of the amount of chloride to bromide and chloride to iodide; and the amount of potassium over rubidium compared to potassium. I am not kidding you here; people spend their days researching this stuff and coming up with curves in order to compare water samples to various brines. There are curves for brines from the Barnett Shale and other oil and gas formations, curves for road salt, curves for landfill leachate. And these fun loving water scientists put together what they call mixing curves. How much water from the Barnett Shale, landfill leachate, etc. would result in what changes to freshwater. You can put your home well water on the mixing curve and see from where any sort of brine might have come. EPA did the comparison of water from the two homeowner wells and brine from the Barnett Shale and found it to fall on the mixing curve. EPA’s conclusion was that the brine intrusion into the homeowner’s wells was from the Barnett Shale. And the supply well, where did it fall? It apparently looked more like landfill leachate.

How could brine from the Barnett Shale have intruded into these two homeowners wells? EPA couldn’t say and with good reason. This was a “retrospective” study. There was no water quality work done before hydrofracturing began in the area or prior to the installation of the brine injection well. So EPA could make no specific conclusions.

I think it is becoming increasingly clear. EPA says impacts to groundwater quality from hydrofracturing do not occur often. However EPA has now found a number of cases where they have concluded that there are impacts. But the source of the impacts cannot always be readily determined because of the lack of groundwater quality characterization and water well sampling prior to and after hydraulic fracturing activity. If we see new regulation in the next few years as a result of EPA’s studies, I am hoping it will be a requirement for good water quality studies before and after hydraulic fracturing.

The Environmental Protection Agency’s (EPA) “Retrospective Case Study in Southwest Pennsylvania: Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources” is a work of nuance and intrigue. An exciting read. Well maybe not to everyone, but for me, it was science done at its best. The scientists used a multiple line theory of investigation to track down the cause of complaints of contaminated water in homeowner’s wells in southwest Pennsylvania. The complaints were similar. After hydraulic fracturing for gas in the Marcellus Shale had occurred nearby, homeowners found water from their wells turbid and odiferous. Their water tasted bad plus it left unsightly stains.

The EPA, as regular readers of this blog know, has been conducting “retrospective” studies of areas with significant complaints of groundwater impacts from hydraulic fracturing to determine if there was actually an impact to people’s drinking water wells and how it might have occurred. The study in southwest Pennsylvania was conducted in Washington County which is a short drive from Pittsburgh. I have visited Washington County and it is a pretty, rolling hill, rural sort of place that has a long history of coal mining and oil and gas development. The first oil well was drilled there sometime in the late 1800’s. Most people get their drinking water from the Monongahela River, but about a quarter of the residents are using groundwater. The groundwater there is pretty shallow, about 50 to 160 feet below the surface and the Marcellus Shale is pretty deep, about 5000 to roughly 7500 feet. The groundwater is generally pretty good, if you are going to drink groundwater. Most domestic wells are primarily producing a nice calcium bicarbonate type water and a lesser number of wells produce a sodium bicarbonate or calcium sulfate type. The problem with groundwater in Washington County is that it has a lot of naturally occurring iron and manganese. The groundwater also has naturally occurring methane gas. Remember methane is one of the components of natural gas but it can also be produced by bacteria as they decompose organic matter.

First, to determine if people’s drinking water wells had been contaminated by hydraulic fracturing fluid, the EPA analyzed for 133 organic compounds commonly used in hydraulic fracturing fluid. This doesn’t mean that companies are using 133 different chemicals every time they conduct hydraulic fracturing. Usually they use less than 10, but the chemical content of the fluid can vary depending on what the company is trying to achieve. So you’ve got to do a full analysis. I am happy to report that EPA found no organic contaminants they could trace to hydraulic fracturing in anybody’s water well.

EPA also analyzed the water for 102 other constituents including metals, stable isotopes, radionuclides, and your basic water quality constituents such as calcium, sodium, chloride and the like. Since there was no smoking gun of organic contamination from hydraulic fracturing in the wells, EPA looked at the results of stable isotope analysis, specifically the stable isotope signatures for the components of water in the drinking water wells – which we all know to be hydrogen and oxygen. The Marcellus Shale has water as well as gas. It is a brine type of water with lots of dissolved solids and other constituents such as sodium, chloride and bromide which make it briny. The brine is called formation or produced water and comes up oil and gas wells during hydrofracturing (remember this tidbit because we’ll come back to it later). Anyway the hydrogen and oxygen stable isotopes of the Marcellus brine and other deep rock formations are very different from shallow groundwater. If there was any movement of the formation water along with hydrofracturing fluid into shallow groundwater, it would show up in these analyses. Even a small amount of this briny fluid entering shallow groundwater would significantly change the stable isotope signature of hydrogen and oxygen in the drinking water wells. Again no bullet holes or dead bodies were found. Hydrogen and oxygen isotopes in people’s drinking water were the same as shallow groundwater in similar aquifers where no hydrofracturing has ever occurred.

Not to be deterred in their investigatory work, the EPA then looked at the stable isotopes of methane. As I mentioned earlier, methane is a component of natural gas and it is also formed by bacterial decomposition of organic material (these are commonly referred to as biogenic methane). The later is very common and occurs in wetlands and other places where you don’t have a lot of free oxygen, such as a groundwater well. Methane, which is composed of carbon and hydrogen, has very distinct stable isotope signatures for those components depending on whether it was produced at depth in an oil and gas formation or at the surface in a groundwater well. Unfortunately there were only two wells sampled that had sufficient methane in the water to analyze for stable isotopes. One sample showed clearly that it was biogenic methane; the other sample was less clear.

So EPA conducted a more definitive stable isotope test. This test was for what is called: dissolved inorganic carbon. Methane is considered organic carbon. There is another carbon that is associated with calcite in the rock formation. Calcite is what makes up limestone. It is calcium carbonate. As it moves along in an aquifer, the carbon in carbonate is oxidized, which results in the formation of carbon dioxide. When the carbon dioxide enters a water well (or other oxygen depleted location) the bacteria love it and use it to make biogenic methane, resulting in enriched inorganic carbon. Dissolved inorganic carbon produced this way has a very distinct isotopic signature compared to the inorganic carbon you find in the brine from the Marcellus Shale. The isotopic signature for dissolved inorganic carbon in the two wells tested was the same as other shallow groundwater in similar rock formations where no hydraulic fracturing has taken place and was totally different from the signature of dissolved inorganic carbon from the Marcellus. Evidence of contamination of people’s drinking water wells from hydrofracturing failed to appear.

Strontium isotope analysis of drinking water also failed to show impact from hydrofracturing. The radionuclide radium was then looked at because the Marcellus brine has some pretty extraordinary levels of both radium 226 and 228. Again there was nothing unusual in the drinking water wells to show impacts to groundwater from hydrofracturing.

The interesting find EPA made was simply using good old fashioned water quality data. EPA had several sets of historical water quality data from the area that had been collected decades before hydraulic fracturing even occurred in Washington County. EPA looked at such mundane water quality constituents as chloride, bromide, sodium and calcium and found that two springs in the southern part of Washington County exhibited some strange behavior during the collection of the 3 sets of samples EPA took over a year and a half period. The springs initially had elevated chloride and calcium levels exceeding both historical groundwater data and other groundwater data from wells EPA had sampled. Even more mysterious, those spurious high numbers decreased during the next two sampling rounds. It looked like the type of data you get when sampling groundwater after a spill. EPA looked around for what might be causing such an anomaly. It didn’t take long to find that both springs were close by and downgradient from an impoundment and reserve pit which had been used during the construction and hydrofracturing of a gas well. Remember the tidbit I told you to about where the briny formation water comes back up the hole during hydrofracturing and well production. The surface impoundment was used to store this water. So finally, here was a culprit. There was an extremely limited effect, since it was local and didn’t impact anyone’s personal water well. But obviously the use of a surface impoundment in this particular case caused leaching into groundwater and impacts to the two springs.

So if EPA couldn’t find any suspects from all of this incredible sleuthing, what did they say caused all of the homeowner’s water quality problems after hydraulic fracturing of the Marcellus Shale in southwest Pennsylvania? Here the EPA kind of failed me. They went into the territory of speculation. It is a good speculation though. It’s based on scientific literature and a good knowledge of groundwater reactions. Being water scientists, the EPA investigators looked at the water complaints, saw that there was a lot of naturally occurring iron and manganese in the groundwater and used their noggins to deduce that staining, taste and odor issues were probably a result of high levels of iron and manganese in the water.  In fact, when they tested the water for iron and manganese, they ran both a filtered and an unfiltered sample. The unfiltered sample was much higher for both of these constituents in the water, which leads them to believe the increased turbidity was the result of a lot of undissolved iron and manganese particulates entering the water wells. What was causing the sudden turbidity? EPA made note in their report that other studies have shown the drilling process for an oil and gas well produces a lot of vibrations and that has resulted in mobilization of iron and other rock constituents, like manganese, into water wells resulting in a lot of turbidity in those wells. So there you go, no contamination from hydraulic fracturing in southwest Pennsylvania, but possibly just poor water quality as the result of the drilling of the gas well. Little consolation for the homeowners who had to put up with foul taste and having their laundry stained, but thank goodness they aren’t drinking something really foul from the hydrofracturing fluid.

Stray natural gas is common in northeast Pennsylvania. It existed before hydraulic fracturing for gas began in the area. The Marcellus Shale is the main rock formation from which natural gas is being extracted, but all the formations above the Marcellus also have natural gas. The Lockhaven and Catskill are the main drinking water formations that people in the area drill into for water supply and are located several thousand feet above the Marcellus Shale. There is plenty of water monitoring data showing natural gas already existed in the water supply formations before hydrofracturing occurred in the area. But between 2009 and 2011, the Pennsylvania Department of Environmental Protection investigated somewhere around 90 complaints of stray gas in domestic water wells. Obviously something new was happening.

When I envision stray gas, I always get this picture in my head of stray cats. You leave the door open one day and your cat slips out. It becomes a stray, living in the woods, killing songbirds for food, trespassing into people’s backyards, and generally making a nuisance of itself. Stray natural gas is really the same thing, you don’t do such a good job cementing your casing and you leave the door open for natural gas to come up the sides of the casing, it enters into groundwater rock formations and sometimes travels through natural fractures in the rock, it slips into people’s water wells and sometimes their basements, it can cause groundwater in the well to become discolored and turbid as iron and other minerals precipitate out of the water, and it generally makes a nuisance of itself because after all natural gas can explode.

The Environmental Protection Agency selected Northeast Pennsylvania for one of their five “Retrospective Studies.”  The selections were made based on complaints of water well contamination in areas that were undergoing hydraulic fracturing for oil and gas. The study being “retrospective” was designed to determine through various chemical tests whether the Environmental Protection Agency could determine if the gas in people’s water wells in northeast Pennsylvania came from hydrofracturing activities in the area.

Based on the Environmental Protection Agency’s research, two main water types are being used for water supply in the study area. There is a nice calcium bicarbonate water in the upland areas and in the river valleys a sodium chloride or sodium bicarbonate type water. Geologists in the area have proposed that rivers followed weaker naturally fractured rock to form the valleys. The geologists further theorize that brines from lower rock formations moved upward through these highly fractured rocks underneath the valleys into the shallower drinking water formations, hence the chloride and sodium. Methane is common in the valley groundwater both in wells and in springs but is uncommon in the upland wells.

The main line of evidence that hydraulic fracturing in the area is the cause of stray gas in water wells comes from stable isotope work conducted by the Environmental Protection Agency and others. In a previous post I mentioned that stable isotopes have a signature. Remember from high school or college science: atoms have electrons, neutrons, and protons. So let’s take carbon as an example, it has 6 neutrons and 6 protons. That is called carbon 12. Get it, six and six is twelve. Okay, about one percent of carbon has 7 neutrons and 6 protons. It is called carbon 13. Since it has one less neutron, carbon 12 is lighter and reacts a little quicker in chemical bonding than its heavy brother. So various compounds that contain carbon have different amounts of carbon 13 to 12 based on their origin. These ratios are expressed in parts per thousand and give a signature that can be used in this case to determine the origin of methane.

Methane, a component of natural gas, is a compound of carbon and hydrogen. Hydrogen also has a stable isotope signature. Methane can be produced by bacteria in surface water. Methane in natural gas and methane produced by bacteria have two different carbon and hydrogen signatures. Methane is just one component of natural gas. Other components include ethane, propane and butane which are also compounds of carbon and hydrogen. And guess what? Each component of natural gas has a very specific ratio of carbon isotopes in relation to the other components for most of the oil and gas deposits around the world. Except in gas shales like the Marcellus where the ratio is reversed. If you got this reversal of the methane and ethane isotopic signatures in water wells, you would know immediately from where the gases originated. The problem is that there is usually not enough ethane found in water wells to analyze.

Okay enough for our background science. The Environmental Protection Agency tested 36 drinking water wells over a one and a half year period. They did three rounds of sampling and analysis. All wells sampled were within a mile of a hydraulic fracturing site. In addition to stable isotopes, the drinking water was tested for chemicals used in hydrofracturing fluid. The good news is that no drinking water wells tested were found to have hydrofracturing chemicals in them.

Some of the 36 drinking water wells the Environmental Protection Agency tested had natural gas that originated in deep rock formations. Three wells had isotopic signatures of natural gases from rock formations above the Marcellus and five had isotopic signatures of possibly the Marcellus or other deep rock formations. What is the cause of the movement of the stray gas? The Environmental Protection Agency cites a 2012 report by the Groundwater Protection Council that blames inadequate cementing of the casing that allowed gas to move from depth into shallower formations. However, the Environmental Protection Agency says that without having been able to sample the water wells before the hydraulic fracturing occurred in the area, it is difficult to determine exactly what the impacts have been to drinking water in the area.

It sounds to me like there is a strong need for groundwater assessment and sampling before hydraulic fracturing is conducted in an area instead of having to ferret out environmental impacts after the fact. The Environmental Protection Agency cites a study in Northeast Pennsylvania done by an oil and gas company prior to fracturing a well 800 feet from a drinking water well. Multiple rounds of sampling were conducted before and after the hydrofracturing occurred. Data showed a 7 fold increase in methane and a 1000 fold increase in ethane in the drinking water well after the hydraulic fracturing took place. Isotopic testing showed the gas entering the drinking water well came from deep gas bearing rocks but not the Marcellus itself. Little consolation to the homeowner I suspect who probably didn’t care where the gas came from, just that it hadn’t been there prior to hydrofracturing.

Can hydraulic fracturing for oil and gas cause groundwater contamination? This is the question I have been waiting to find out from the U.S. Environmental Protection Agency’s hydrofracturing scientific investigation and studies. Of course if you have a spill, there is always the potential for contamination. But does the actual process of inducing fractures through injecting water and chemical additives under pressure down a well actually cause contamination, either from the hydrofracturing fluid or natural gas migrating into the groundwater. I’ve read through the Environmental Protection Agency’s “Draft Assessment of the Potential Impacts of Hydraulic Fracturing for Oil and Gas on Drinking Water Resources.” I didn’t have to read all 998 pages, just the Executive Summary and the Chapter on Injection. The answer is there are documented cases where the hydrofracturing process itself has contaminated groundwater. Incidences, as the Environmental Protection Agency has stated before, are rare. The evidence comes primarily from the case studies that the Environmental Protection Agency conducted. They have released the case studies as well as the Draft Assessment and I plan to take a look at the case studies in the next few weeks and provide more information on how they determined contamination did or did not come from the hydrofracturing process.

The Environmental Protection Agency always does a good job on their reports. The Draft Assessment is an excellent compilation of the scientific literature on the subject. They have summarized dozens of published research papers. As you can imagine, there has been a lot of recent research in the area of hydraulic fracturing and its possible impact on drinking water. The Draft Assessment also looks at data on well construction and practices. This data was gathered through a survey of service companies that perform hydraulic fracturing for oil and gas companies. The Environmental Protection Agency used the collected data to determine what practices are being used to protect groundwater. As advertised in the Study Plan for the current report, a numerical model was conducted and has been published in the scientific literature. I hope to get a copy of that in the next few months and take a look at it.

The Environmental Protection Agency also gives a litany of possible ways natural gas and chemicals from fracturing fluid could enter the groundwater. These include everything from poor cementing of the casing protecting groundwater to casing failure during hydrofracturing. You could say that the Environmental Protection Agency has validated Murphy’s Law: anything that can go wrong will go wrong.

Right now the Draft Assessment is undergoing review. With the amount of scientific literature quoted in the report, the review needs to be conducted before I write anything further on the Assessment Report as interpretations made in the report may change. So I’m going to concentrate on reviewing and writing about the case studies while that process is ongoing.

The Environmental Protection Agency finally released their “Draft Assessment of the Potential Impacts of Hydraulic Fracturing for Oil and Gas on Drinking Water Resources” last Thursday June 4, 2015. They held two webinars on Friday about the contents of the report. If you’ve been reading this blog for a while, you knew that the report was due for release, you’ve also gotten the background on what the Environmental Protection Agency has been studying and why. If you are a new reader of this blog, go back and check out previous posts. The posts will give you information on the studies the Environmental Protection Agency has been conducting.

I was excited to see the report come out even though it is 998 pages and I am committed to reading the whole thing. In addition, the Environmental Protection Agency published a bunch of new scientific papers on hydrofracturing. So I will be reading up for a while on all this new scientific information. I will be posting about the contents of the report so you can get the in-depth information without having to read the whole 998 pages yourself. The Environmental Protection Agency will be accepting comments until August 28, 2015.

The Environmental Protection Agency said that their studies found no widespread contamination of drinking water resources by hydraulic fracturing. That is a pretty strong statement. However, The Environmental Protection Agency also stated their studies have identified vulnerabilities that need to be addressed by state regulators when permitting hydraulic fracturing wells. So it was a good news, bad news sort of message. Look for future posts on this blog about the report results.

This post is part of a series on EPA’s Hydraulic Fracturing Study. Previous posts will give you more detail on the specific case studies EPA is conducting and you may want to read them prior to reading this post.

EPA is running a number of standard water quality tests as part of their water well sampling for their case studies. These tests characterize the water. Standard measures for water are things like temperature, pH, Total Dissolved Solids (you’ll see this referred to as TDS), specific conductivity, alkalinity, turbidity, dissolved oxygen, oxidation/reduction potential, ferrous iron, and hydrogen sulfide.  EPA will also be looking at existing water quality data collected for the case study areas by government agencies whose business is to characterize water resources. Your average person only generally knows they have hard water, or too much lime that leaves a ring in their bathtub, or their water smells like rotten eggs. They don’t know if they have a bicarbonate or alkaline water, or low dissolved oxygen, or hydrogen sulfide. But your water scientist will. These are water characteristics that they use to describe water. Get one of these water scientists at a dinner party and they will be telling you how your favorite European mineral water gets its taste. EPA’s water scientists will look for changes in water quality characteristics or unusual test data and deduce if something may be going on in the well they are testing.

EPA is testing a large number of chemicals that hopefully aren’t characteristic of your average drinking water. These are mostly chemicals associated with the components of hydrofracturing fluid. Hydrofracturing fluid is generally over 98 percent water but the remaining 2 percent is composed of additives that help the engineer get the oil and gas out of the rock and into the oil and gas well. The additives EPA is testing for are chemicals such as glycols, acids, surfactants, volatile and semi-volatile organic compounds. Volatile organics are things like toluene and styrene. Semi-volatile organics are things like 1,2,4-trichlorobenzene. These are not good to drink.

There are also natural substances commonly found in the flowback water that are removed from the rock during the fracturing process. Some of these are being tested for as well. These are arsenic, manganese and iron. And EPA is testing for chloride and bromide which are characteristic of the flowback water as well. If you have been reading this series of posts on hydrofracturing you will remember that EPA has concerns about adequate treatment of chloride and bromide from flowback water at Publically Owned Treatment Works. Natural organic material is also being tested. And EPA is testing for methane, ethane, and propane which are all components of natural gas.

Finally EPA is testing for: stable isotopes of the components of water, which we know are hydrogen and oxygen; stable isotopes of hydrogen and carbon, which you may not know are the components of methane; and strontium. The easiest explanation of why EPA is analyzing for them is because stable isotopes have different ratios depending on how they were produced and where they came from.

This is kind of an aside, but did you know certain companies who require their products to contain a specific proprietary ingredient that only they make often check stable isotopic ratios of their product manufactured by contractor entities? Why? To see if the contractors are using the proprietary ingredients! They can tell by the stable isotopic ratio.

In EPA’s case they are looking at what the usual stable isotopic ratios are for water, methane and strontium in the case study area. If EPA’s well samples in the case study area then show differences from what the normal isotopic ratios are, it is an indication something might have been introduced. In other words it is an indicator of contamination.

Oh wait I forgot, EPA is also testing for NORM. Remember that from an earlier post? It is the naturally occurring radioactive material.

All in all this is a lot of testing and it will be done at several EPA laboratories.  EPA should have a very good picture of whether water in people’s wells has been contaminated and it should help them draw some conclusions on potential sources of the contamination.