Air Quality in the Barnett Shale - Part 11: Is there a real concern for DISH, Texas?

So what do we know so far regarding the real health concerns for the citizens of the Town of DISH, Texas?:

• Benzene and other chemicals were found in the seven samples collected during one 24 hour sampling event conducted by Wolf Eagle Environmental.
• The TCEQ has sampled the air in the Town of DISH, Texas and reports hourly values below the short-termAir Monitoring Comparison Values (AMCV)  
• The TCEQ has sampled the air in the Town of DISH, Texas and reports hourly values below the short-termAir Monitoring Comparison Values (AMCV)  

Here is what I gathered from the TCEQ website for air monitoring at DISH, Texas:

Note: Report generated on Dec 16, 2010.  Monthly and Yearly data reported for BTEX.

As you can see, the amount of BTEX (Benzene, Toluene, Ethylbenzene, and Xylene) is under the AMCV for each chemical.  That's a good sign.  But lets make the assumption that the 24 hour results reported by Wolf Eagle Environmental are what the citizens of DISH, Texas are being exposed to on a regular basis.  Would there be a health concern?

That's a difficult one to make a call on.  In fact it is so uncertain that even Wolf Eagle Environmental and Wilma Subra in any of their reports do not make any claim what-so-ever as to these levels creating a undo health risk.  All that is said is that they exceed the ESL for some of the chemicals found.

The TCEQ, on the other hand, does state:

"24-hour air monitors in the Barnett Shale area are showing no levels of concern for any chemicals." and "there are no immediate health concerns from air quality in the area" and "that when they are properly managed and maintained, oil and gas operations do not cause harmful excess air emissions.”

Now I know better than to rest my case on one set of data.  However, I have at my disposal - and anyone clicking the links I cite does as well - a whole bunch of data or 'n'.  This gives me more confidence to agree with the statement TCEQ has issued above.

There is one more issue in play that leads me to conclude that the air is safe and that the folks in the Town of DISH, Texas are not going to experience " health concerns from air quality in the area."

Exposure is but one step of the K.C.Donnelly Risk Paradigm I discussed in Part 2.

What needs to happen after exposure to a chemical takes place is uptake.  That is, the chemical has to enter into the body where the dose, time, and pharmacokinetics now come into play.

The question becomes, OK, if they are exposed, how much are they actually getting into their system?  In order for a health effect to manifest, uptake must take place.  And if uptake has taken place, we can measure the actual concentration of the chemical in the blood stream or tissue.

And wouldn't you know it, that has been done.

Much of the concern about natural gas operations has been centered in DISH, so in early 2009, the Texas Department of State Health Services performed blood tests on 28 DISH residents (representing about 13 percent of the town’s population).

Test results showed that the exposure of DISH residents to VOCs was similar to that of the general U.S. population, and that exposure to certain contaminants was no higher than that of the general U.S. population.

The study further found that the only residents who had higher levels of benzene in their blood were smokers. Cigarette smoke contains benzene, so finding this in smokers’ blood is not unusual, the department noted. (1)

So now what do we know?

• We know that we have detected chemicals contaminants in the 24 hour samples collected by Wolf Eagle Environmental
• We can assume exposure has taken place.
• We can show - through blood tests - that exposed citizens have levels of contaminants no higher than those of the general US population.

So what can we conclude from all this?  That excluding odor, noise, and catastrophic events, the TCEQ is correct in asserting "that when they are properly managed and maintained, oil and gas operations do not cause harmful excess air emissions.”


Next Post: Air Quality in the Barnett Shale - Part 12: Oil & Gas, it's better if you go green!

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Air Quality in the Barnett Shale - Part 10: How not to describe Toluene

So here I am on my 10th rant...err, I mean post.  What started all of this was a simple Google search looking for information on air quality and oil & gas exploration/production involving frac'ing in Texas.  What I found mentioned over and over again mentioned sampling performed in the Town of DISH, Texas by Wolf Eagle Environmental.  Reading their report, written by an MPH named Alisa Rich, I come across a number of descriptions as to the hazards posed by the contaminants detected in the seven samples they took in the Town of DISH, Texas back in September of 2009.

The one on Toluene was what started these posts.  Nothing makes me madder than when someone who is in the know reports faulty, misleading or incorrect information to the general public.  As an MPH she knows better.  Although what she said was factually true, the context it was put in was misleading:

Lets look at a different chemical to illustrate how misleading a statement like this can be:

Phosphoric Acid - CAS Number 7664-38-2  

Corrosive. Causes skin and eye burns. Harmful if inhaled or swallowed. Irritating to respiratory system. Prolonged exposure may cause chronic effects.  This product is considered hazardous under 29 CFR 1910.1200 (Hazard Communication).  Risk of serious damage to eyes. Do not get this material in contact with eyes.  Causes skin burns. Harmful if inhaled. Inhalation of vapors or mists of the product may be irritating to the respiratory system. Prolonged inhalation may be harmful. Do not breathe dust/fume/gas/mist/vapors/spray.  Harmful if swallowed. Components of the product may be absorbed into the body by ingestion. Ingestion may produce burns to the lips, oral cavity, upper airway, esophagus and  possibly the digestive tract. Circulatory collapse. Unconsciousness, possibly death. Do not ingest. Components of this product are hazardous to aquatic life. May cause long-term adverse effects in the environment. (1)

Pay particular attention to the section in red.  Wow!  That phosphoric acid must be really bad stuff!  Now lets look at a can of Coke, or Pepsi, or Dr. Pepper, or any other carbonated drink.

So will drinking a can of Coke cause you to suffer "Circulatory collapse. Unconsciousness, possibly death?"  

No.

Is Coke, which contains phosphoric acid, "Harmful if swallowed?"

No.

Does ingestion of this product "produce burns to the lips, oral cavity, upper airway, esophagus and  possibly the digestive tract?"

No.

And the reason?  The dose!  In other words, there is a "safe amount" of phosphoric acid that a person can be exposed to.  Carbonated drinks contain that "safe amount."

So were the citizens of DISH, Texas exposed to an amount of Toluene that would/could present any of the hazards described in Wolf Eagle Environmental's report?

No. (2)(3)

And yet both Alisa Rich and Wilma Subra presented to the Town of DISH, Texas reports that imply that the amount of contaminants detected in the seven samples exposed the citizens to "a neurotoxin." (4)

If we go back to looking at chemical exposure in terms of exposure to a dog, in DISH, Texas a dog was indeed found to be present.  Even if we assume worst-case as the TCEQ did in their memo - increasing the amount of chemicals detected in a 24 hour sample to 24 times the levels detected - what was detected at the Town of DISH, Texas by Wolf Eagle Environmental, was a dog that looks like this:

But the way their report was worded, it describes a dog that looks like this:

So as Wilma Subra concludes in her report:

The data from the report should be used to educate community members living in the area with the highest concentrations of chemicals and chemicals in excess of TCEQ ESLs in the air they are being exposed to.

Well you now have the data and the correct context to help make a proper determination as to the risk posed by the oil & gas production that is taking place.


Next post: Air Quality in the Barnett Shale - Part 11:  Is there a real concern for DISH, Texas?


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Air Quality in the Barnett Shale - Part 4: Exceeding TCEQs Short-term ESLs

So what do we know so far:

1. Wolf Eagle Environmental and Wilma Subra used sample results collected from one 24 hour sampling event to compare against Long-term ESLs that are used to evaluate modeled 1-year concentrations.
2. For the seven sample locations, there were a total of 13 times where a chemical detected exceeded the TCEQ's Short-term ESL.
3. TCEQ states that exceeding the ESL "does not necessarily indicate a problem but rather triggers a review in more depth."
4. TCEQ states that “[a]fter several months of operation, state-of-the-art, 24-hour air monitors in the Barnett Shale area are showing no levels of concern for any chemicals. This reinforces our conclusion that there are no immediate health concerns from air quality in the area[.]"

Lets assume that the values obtained from this single 24-hour sampling event represent the amount the citizens of DISH are exposed to, day in, day out.  Because this was a sample collected over a 24 hour period, the 1 hour concentration is equal to 1/24 of the concentration detected and reported.  So, if the highest concentration of benzene reported by Wolf Eagle Environmental was 77.7 ppb (Airfield @1:29) the one hour concentration would be 77.7 / 24 =  3.24 ppb.


Note 2/14/11: I looked at it as an average concentration,  The way TCEQ looked at it, was that there was a single one hour level which was diluted with 23 hours of "clean air."  In re-looking at this, because we are comparing a sample concentration to a one hour ESL (the amount that would be the highest concentration in an hour whereby no adverse health effects would be found) the TCEQ assumption fits better than my averaging assumption.

The reason we divide by 24 is because the sample canister was left on for 24 hours. The Short-term ESLs used by the TCEQ are based on the concentration that would be present in a one hour block of time.  Because we use ppb - or parts of contaminant per billion parts of air - to make comparisons, leaving the canister open for more than one hour would take in more parts of contaminant but the total volume of air would remain the same.  

Canister Sampling is  method of taking a sample of air that uses a stainless steel canister that has been scrupulously cleaned and is under a vacuum. The operator opens the valve on the canister, allowing the air sample to rush into the canister to fill the vacuum. When the canister is opened all at once allowing the air to be sampled over the span of a few seconds, [TCEQ] terms this an instantaneous sample.  A controller can be put on the canister sampler controlling (slowing) the flow of air into the canister over a prescribed time, i.e. 30 minutes, 1 hour, or 24 hours. The samples in the canister are then analyzed on another instrument, typically a gas chromatograph (GC).

TCEQ also recognized this flaw in Wolf Eagle Environmental's reporting but gave them the added benefit of conservatively assuming "that the chemical had a maximum concentration for one hour and was not detected for the remaining 23 hours."  In their memo dated October 29, 2009, TCEQ, in order to compare Wolf Eagle Environmental's 24-hour concentrations with a 1 hour value, multiplied them by 24.  In this manner, the TCEQ compared reported concentrations of the ambient air at the Town of DISH that were 24 times higher than actually detected!  They did, however, note: "This may or may not represent actual conditions."

So now we can add one more to the list of what we know so far

5. Sampling and analysis reported 24 hour concentrations which were compared to ESL values that represent the concentration collected in a one hour period of time.

 Ready for another one?  Yes, there is a number 6.  One more error in their reporting of certain chemicals exceeding TCEQ's ESLs.  The ESLs they used to compare with in their "Revised Air Study Documents" were the wrong type of values to use.


According to the TCEQs AMCV document called "Uses of Effects Screening Levels (ESLs) and Air Monitoring Comparison Values (AMCVs) Revised (May 2010)" Although the same Short-term and Long-term were used for both air permitting and air monitoring, air concentrations of chemicals collected in air monitoring samples represent emissions from multiple chemicals and from different facilities and sources.  For review of air monitoring data, the health-based ReV is appropriate.

ReVs [reference values] are designed to protect the most sensitive individuals in a population by inclusion of uncertainty/variability factors (UFs). UFs account for differences between study animal and human species, variability within the human species, and uncertainties related to the applicability and completeness of the available data. Since UFs are incorporated to address data gaps, variability, and other uncertainties, exceeding the ReV does not automatically indicate that an adverse health effect would occur.

For air permit applications, site-wide modeled concentrations for one chemical at a time are evaluated.  Therefore, for air permitting, an additional buffer is applied to the acute or chronic ReV to calculate the acute and chronic ESLs. The final acute and chronic ESLs developed using the Guidelines are 70% lower than the respective acute and chronic ReV.
  

Because there are "significant differences between performing health effect reviews of air permits and the various forms of ambient air monitoring data," the [TCEQ] has begun using the term “air monitoring comparison values” (AMCVs) in evaluations of air monitoring data.  

AMCVs are chemical-specific air concentrations set to protect human health and welfare. Exposure to an air concentration at or below the AMCVs is not likely to cause adverse health effects in the general public, including sensitive subgroups such as children, the elderly, pregnant women, and people with preexisting health conditions. AMCVs are a collective term that refer to all values used by [TCEQ] staff to review ambient air monitoring data.

The use of different values and different terminology is appropriate because the air monitoring and air permitting programs perform different functions in the protection of human health and welfare."

• The short-term AMCV, based on acute exposure health and welfare data, is compared to monitored concentrations that can be instantaneous or up to 1-hour, which represent a point in time for a specific location.
• The short-term ESL, based on acute exposure health and welfare data, is compared to the modeled 1-hour Maximum Ground Level Concentration (GLCmax).
• The long-term AMCV, based on chronic health and welfare data, is used to evaluate annual averaged monitored concentrations or annual concentrations averaged over multiple years (if available), which represent multiple points in time for a specific locations.
• The long-term ESL, based on chronic or lifetime exposure health and welfare data, is compared to the worst-case annual GLCmax.

So basically, the work performed by Wolf Eagle Environmental looked at the contaminants detected and reported them as if they were being addressed for an air permit.  Lets assume that the values obtained did represent the concentration in air that a citizen of the Town of DISH was going to be exposed to.  What then?

Getting back to benzene and xylene (m & p), how many times was there an exceedence?  And by how much?

Now remember, there are two things in play here.  1st, the ppbv results shown are for 24 hours worth of sampling and could be 24 times higher than what you would have seen if the sample was collected for just one hour.  And 2nd, the ESLs are 70% lower than the reference values.  So, because none of these values exceed the AMCV, we can safely say that exposure to an air concentration at or below the AMCV is not likely to cause an adverse health effect in the general public, including sensitive subgroups such as children, the elderly, pregnant women, and people with preexisting health conditions.

Ignoring the incorrect sampling...ignoring the incorrect comparison, and assuming that these values represent the amount a citizen of the Town of DISH is exposed to, will there be any negative health concerns from these contaminants?

Here is what the TCEQ states in their memo:

The highest potential 1-hour maximum benzene concentration [actual x 24] is below the health effects level observed in short-term animal and human studies; however, it is possible that adverse health effects could occur from exposure to this concentration. It was not possible to determine if residents were exposed to this concentration of benzene based on the information provided.

Here is what I say - and I am not going to far out on a limb: Not likely - because even if you multiplied the contaminate concentrations by 24 like the TCEQ, and even if they exceeded the ESL and the AMCV, there is a margin of safety - uncertainty - built into these comparison values.  It all comes down to how we calculate risk and the value we use in the calculation for the ESL and AMCV.  It's all about the reference value - the ReV.

Air Quality in the Barnett Shale - Part 5:  'n' is for sample size.

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Air Quality in the Barnett Shale - Part 1: Introduction

It all starts like this.....

Researching air quality in areas where frac'ing is taking place in Texas to obtain natural gas.  Came across TCEQ web page titled "A Commitment to Air Quality in the Barnett Shale" that states:

“After several months of operation, state-of-the-art, 24-hour air monitors in the Barnett Shale area are showing no levels of concern for any chemicals. This reinforces our conclusion that there are no immediate health concerns from air quality in the area, and that when they are properly managed and maintained, oil and gas operations do not cause harmful excess air emissions.”

All is good!  Reading further, they mention that much of the concern has been from a town called DISH.  Yeah, DISH - they changed the name for free access to satellite TV as publicity for the company with the same name.

Going to the Town of DISH's website, I see a link called "Dish Air Quality Results" which brings me to a page with a number of reports.  Clicking "Dish, Texas Ambient Air Monitoring Analysis" I get a report by Wilma Subra titled "Evaluation of Town of DISH, Texas Ambient Air Monitoring Analysis" which summarizes the conclusion of a report by a company called "Wolf Eagle Environmental" which had been hired by the Mayor, Calvin Tillman, to perform ambient air monitoring analysis in the Town of DISH.

In the summary of the final report - and reiterated by Ms. Subra - the following statement is made:

"Air analysis performed in the Town of DISH confirmed the presence in high concentrations of carcinogenic and neurotoxin compounds in ambient air near and/or on residential properties.  The compounds in the air indicate quantities in excess of what would normally be anticipated in ambient air in an urban residential or rural residential area. Many of these compounds verified by laboratory analysis were metabolites of known human carcinogens and exceeded both Short-term and Long-term effective screening levels (ESL) according to TCEQ regulations."

OK, so the TCEQ says there are "no levels of concern for any chemical" but Ms. Subra and Wolf Eagle Environmental say the air contains "the presence in high concentrations of carcinogenic and neurotoxin compounds" and they "exceeded both Short-term and Long-term effective screening levels (ESL) according to TCEQ regulations."  So which is it?  Exposure at no level of concern or exposure to carcinogenic and neurotoxin compounds?

Hmmm?  What carcinogenic and neurotoxin compounds were detected in the air samples taken by Wolf Eagle Environmental?  Reading the report a little further I find Benzene and Toluene identified as two of the chemicals of concern found in the samples at "high" concentrations.  OK...what do they have to say about these two chemicals presenting a health concern at concentrations in the parts per billion (ppb) range...

...ding! ding! ding! warning! my "no they did not just say that did they?!" alarm goes off - in particular - over this one statement made by Ms. Subra in her report (emphasis mine) as well as one by Wolf Eagle Environmental:

"The air sample from Air Field - corner SE contained 8 chemicals that exceed the TCEQ ESLs.  Benzene, a know human cancer causing agent, was present in the highest concentration of all stations sampled.  The concentration of Benzene in the air exceeded the Short-term ESL by 1.45 times and the Long-term ESL by 55 times the standard.  The Benzene concentration at this sample location was 6 times the next highest Benzene concentration (at 9203 Chisum).  Xylenes (m & p), a neorotoxin, was present in the highest concentration of all stations sampled and exceeded the Long-term ESL by 2 times." [Subra]

 There is evidence that chronic occupational exposure to Xylenes is associated with neurological effects. [Wolf Eagle Environmental]

There is not too much that gets my blood boiling more than using factual and correct information in a way that is misleading and/or incorrectly used.  All this does - purposely or unwittingly - is perpetuate unnecessary confusion and/or fear in the public affected.  This is inexcusable in a scientific paper - especially when placed there by "experts" that should know better than to use wording that can easily be misconstrued by a public not very knowledgeable in understanding toxicity, toxicology, and risk.

So who are these experts?

• The Wolf Eagle Environmental report was signed by Alisa Rich who is working on her PhD and also, like me, is a MPH.  
• Ms. Subra owns a "chemistry lab and environmental consulting firm" and "provides technical assistance to citizens, across the United States and some foreign countries, concerned with their environment by combining technical research and evaluation. This information is then presented to community members so that strategies may be developed to address their local struggles."  She also received the MacArthur Fellowship Genius Award.

Great, I am going up against a PhD and a Genius.  But I am not daunted.  You can read my credentials by looking at my CV in the tab above.  All I have to challenge them with is a MSPH, but after these next few posts, you can either agree with my indignation over how they worded their reports or you can choose to accept what is unequivocally implied from their conclusion. All I am attempting here is to help "ordinary" citizens understand, cope with and combat environmental issues" using data and information in the correct context and actual reality in which it is found.

So before we move on to the next post, let me spell out my bias.  I have no "dog in this hunt" in any way, shape or form.  I am pro business AND pro environment.  I am a scientist and a passionate defender of public health.  I take my MSPH and CHMM credentials serious and would never do anything to purposely taint them by not telling the truth, the whole truth, and nothing but the truth.  In short, it is my attempt here to be nothing more than an honest broker.

Edited 2/16/11 in green

Next Post.  Air Quality in the Barnett Shale - Part 2:  Exposure to a toxic chemical.


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