Tuesday, March 29, 2011

Grabbing sludge with my bare hands

I was watching Undercover Boss this past Sunday about a guy named Bill Massa who just took on the CEO/President job at a company called Synagro billed as "America's largest waste treatment corporation today."

Normally I don't watch these types of shows, except for Dirty Jobs, because they are a bit too patronizing and...well kind of staged.  But the word "waste" piqued my curiosity.

Just like when watching Dirty Jobs, I cringed when I saw his employees direct him to perform certain tasks or told him about conditions on the job.

Here is a bit of news.  Wearing a hard hat and goggles does not mean you work for a safe company.  This is similar to putting up a silt fence around a construction project and believing it to be storm water compliance.

To be fair, we only get a small window into their operation, so there is stuff we are not seeing, but what I saw was enough to tell me that Synagro needs a stronger grasp on safety and OSHA to replace what they currently have in place now.  This is not to imply that things are bad, just that simple things that should be standard operating procedures were not being followed.

First. If you are going to pull a sample of raw sewage, wear gloves.  Yeah its funny watching him get poop all over his hands, but it's raw sewage, you know, containing poop which contains all types of nasty disease causing bugs.

Second.  When taking a sample from an auger that is still operating, requiring that you reach down into the troff, a dead-man's switch or something should be in place.  Safety is only an issue if someone gets hurt, and in this case, falling into that auger would most likely be serious.  Engineer out the problem, turn it off or provide something to prevent falling into the auger.

Third.  That area only has one person working there and she is required to collect a sample from an operating auger, climb stairs, operate machines, drive trucks, and who knows what else.  One person?  What mechanism is in place for her to get help if she has an accident or gets into a bad situation where she requires help?

Forth.  Note to employers: OSHA requires that you provide drinking water and bathroom facilities for your workers.  I'll cut you some slack on a short-term project, but when you are cleaning out large sludge ponds which requires your employees to be there for multiple weeks, get them a restroom and give them breaks. (Mr. Massa is correcting this error)

Fifth.  I am really curious as to how strong their lockout-tagout program is there, or even if they have one.

Sixth.  If you are finding tampon dispensers clogging up the machine, then there is no telling what else could also be in there.  Surgical gloves are not strong enough for reaching your hands into crevices to pull our clumps of dry crud.  Wear the proper gloves.

Seventh.  Paper dust masks?  Really?  With that much dust flying around and what that dust could contain?  If you are not going to put folks in at least a half-face with HEPA, at least put them in a N95 or N100.

Eighth.  One thing I hate about these shows is the cavalier way they portray going into a confined space, especially a permit required confined space.  I am going to assume that they did everything right on this one, but I wish they would have shown Mr. Massa going through confined space training, getting a safety briefing before he went in, signing the entry form, or receiving some information on the dangers of entering the confined space other than "if the strong smell of ammonia makes you woozy, tell me, we don't want you passing out into the sludge" (or something to that effect).

Eight is a pet-peeve of mine.  Confined spaces kill.  Don't believe me?  Watch this.

Oh, and for those of you who think OSHA just gets in the way of business, I offer this episode and Dirty "that burning you feel is the caustic" Jobs as proof that they are still very much necessary and needed.

Well anyway, here's to good leadership and a safer company under Mr. Massa.  I wish them well.

Saturday, March 26, 2011

Air in the Barnett Shale: Formaldehyde

Well heck, thought after 30 posts I was going to move on, but a question was asked on high formaldehyde concentrations in the one hour TO-11A formaldehyde samples at the Quicksilver (Gas Services) Lake Arlington (COFW5) site.


Here is what appears on page 164 of the BSEEC report:

Now when I looked at this, my first question was-  how does this site compare to the other sites from which formaldehyde samples were collected?  Well heck, only Chesapeake Arc Park (COFW4) was sampled for formaldehyde.  Here is what the BSEEC report states for this location (page 19)
One exception might be formaldehyde, which was detected in a downwind sample at a concentration slightly higher than those found upwind.
The next thing I look at is - how does the downwind sample compare to the upwind sample?  For COFW4, sample CAP4DC1 it was 12.19 ppbv - with upwind formaldehyde sample results of 7.79, 4.86, and 4.81 ppbv.  OK, so a bit elevated when compared to background (upwind samples).  This downwind sample location appears to be right next to the compressor engines.  So that's probably to be expected if they are not electric powered.

So what do we see when looking at COFW5, the Quicksilver Lake Arlington site?

  • Downwind samples at the fence line are 81,29, 4.86, 5.37 ppbv.
  • Downwind samples north of Highway 303 are 68.80 and 114.41 ppbv.
  • Eastern sample some distance from fence line  was 4.16 ppbv.
Assuming that the air is moving in a steady south to north direction, how does the fence line sample upwind compare to the downwind samples?
  • Upwind fence line sample (West) was 126.91 ppbv with the downwind fence line sample at 81.29 ppbv.
  • Upwind fence line sample (center) was 100.31 ppbv with the downwind fence line sample at 4.86 ppbv
  • Upwind fence line sample (East) was 4.26 ppbv with the downwind fence line sample at 5.57 ppbv
What I see here is an indication that there is a source of formaldehyde directly to the south of the O&G site.  And if you continue looking at the concentration of the formaldehyde moving in a south to north wind direction, you will see that the downwind fence line samples are less than the samples collected north of Highway 303 indicating that vehicles are a likely source of formaldehyde around that area.

So why are the upwind samples so high when there is nothing industrial nearby to the South?  Good question.  Here is what they say about that in the BSEEC report (page 21):
The formaldehyde concentrations at the three westernmost sampling stations, QLA5DW, QLA5UW, and QLA5UC, were very likely caused by emissions from an unidentified lowelevation source located to the near south/southwest of the NG Site. The depicted concentration pattern suggests that emissions from this unidentified source were transported northward in a well-defined plume, with the highest monitored concentration at QLA5UW (126.91 ppbv), a slightly lower concentration at QLA5UC (100.31 ppbv) to the east of the plume centerline, and a slightly lower concentration monitored at QLA5DW (81.29 ppbv) due to the continued dispersion of the northward advecting plume. Formaldehyde concentrations at sampling points located on or near the eastern portion of the NG Site (QLA5UE, QLA5DC, and QLA5DE) are indicative of background levels because those sampling sites apparently were not within the plume that affected the sampling points in the western portion of the sampling domain.
It's hard to make a determination on two sample locations and one sample event.  However, it would appear that there are other sources for the high concentrations of formaldehyde found in the samples at COFW5.

So what does all this mean to a person concerned about formaldehyde in the air they are breathing?  Well, it appears that it would most likely be there even if the Quicksilver (Gas Services) Lake Arlington (COFW5) site was not.  So the next question now becomes - at those levels is there a concern?

Here is what the EPA has to say about formaldehyde:
  • Formaldehyde is quickly broken down in the air, usually within hours.
  • Formaldehyde dissolves easily but does not last a long time in water.
  • Formaldehyde evaporates from shallow soils.
  • Formaldehyde does not build up in plants and animals.
OK, since we are dealing with ambient air, that's good news, especially the breaking down part and the lack of bio-accumulation.  What else does the EPA say?
Formaldehyde levels in outdoor air range from 0.0002 to 0.006 ppm in rural and suburban areas and 0.001 to 0.02 ppm in urban areas.
OK, definitely in an urban area, so 0.001 to 0.02 ppm is 1 to 20 ppb. Hmmm...some of those levels found are high compared to a "normal" urban setting.  

What does the EPA say about a "safe" exposure rate?
The EPA has determined that lifetime exposure to 1 ppm formaldehyde is not expected to cause any adverse effects.  The Occupational Health and Safety Administration (OSHA) has limited workers' exposure to an average of 0.75 ppm for an 8-hour workday, 40-hour workweek.
This would mean an exposure of 1000 ppb should not result in any adverse health effects.  Since the OSHA worker level is more conservative, lets go with that; 750 ppb.  So if these levels are the benchmarks for no adverse health effects, the levels in and around the Quicksilver (Gas Services) Lake Arlington (COFW5) site should pose no long term health effects.  

The TCEQ, on the other hand, has set the "safe" level of formaldehyde at 41 ppbv for short-term health and 8.9 ppbv for long-term health (AMCVs) which is considerably lower than what EPA determines as a "safe" level.

Well that's a bit of a difference and it appears that the air in this area exceeds the long-term health levels, if - and that's a big if - the one hour sample is representative of the air for 8760 hours in a year over a lifetime.  So because of this uncertainty we - yeah you guessed it - need more research at this location.

What about formaldehyde and cancer, especially the possibility that it may have been responsible for a "fast acting bone cancer?"  Here is what the EPA has to say about formaldehyde and cancer:
The Department of Health and Human Services (DHHS) has determined that formaldehyde is a known human carcinogen based on human and animal inhalation studies.  OK, cancer is bad, but what type of cancer?  Here is what the National Cancer Institute has to say about formaldehyde:

Basically, because formaldehyde breaks down quickly, its impact is mostly on the respiratory system, but may be responsible for myeloid leukemia in humans.  What about bone cancer?  The EPA reports:

...and here is what the EPA concluded about that meta study:
This study demonstrated that there was insufficient evidence to firmly associate occupational formaldehyde exposure with the observed cancers, even when considering that the SMRs for the unexposed workers were small.  No consistent correlation was noted between cumulative exposure and the risk of any cancer.  
In these epidemiological studies, workers - who are constantly and consistently exposed to formaldehyde - were looked at for an increase in cancer.  These individuals were exposed in the ppm range (1000 ppb).  So, based on this, it is unlikely that the ambient air concentrations found at the Quicksilver (Gas Services) Lake Arlington (COFW5) site for formaldehyde would contribute to an increase in cancer.

Still, if we are going to use the TCEQ's AMCV as our benchmark, there is something in this area contributing to a formaldehyde concentration above the AMCV.  This may be from the cars on Highway 330 or it may be from some "emissions from [an] unidentified source [that was] transported northward in a well-defined plume."  It does not appear to be from the COFW5 location based on the high upwind concentrations detected so the culprit is still out there.


Tuesday, March 22, 2011

Air in the Barnett Shale: Bibliography

Information on air quality in the Barnett Shale Area & Oil and Gas Production Environmental Issues in General.

TCEQ: Barnett Shale Air Sampling Map Viewer

TCEQ: Barnett Shale: Technical Questions Answered

RRC: Barnett Shale Information

RRC: Eagle Ford Information

RRC: Oil & Gas Permits

RRC: Oil and Gas Division - Texas Administrative Code-  Water Protection

RRC: Memorandum of Understanding between the Railroad Commission of Texas (RRC) and the Texas Commission on Environmental Quality (TCEQ)

Environmentally Friendly Drilling System (EFD)

Congressional Research Service:  Comparison of Selected Oil and Gas Regulations in Texas and Colorado

DISH: Alisa Rich & Wolf Eagle Environmental Reports for Town of Dish, Texas


Kleinfelder: January 2011: Town of Flower mound Limited Air Quality Evaluation

BSEEC: Ambient Air Quality study, Natural Gas Sites Cities of Fort Worth & Arlington, Texas, Barnett Shale Energy Education Council (BSEEC)

ERG: Natural Gas Air Quality Study Interim Report Executive Summary


Sunday, March 20, 2011

Air Quality in the Barnett Shale - Part 30: The End... finally!

It all started...so long ago...29 posts ago to be exact, not including this one.

There I was trying to get a bit of information on the air requirements for oil & gas fracing operations in Texas, when I stumbled across the final report Alisa Rich of Wolf Eagle Environmental prepared for the Town of Dish, Texas.  That started Post 1.

Now I promised myself I was not going to write a rant or indignation type of blog; that this blog was going to be nothing more than trying to explain complex environmental laws and regulations and how they impact day-to-day operations. I also wanted to talk about public health issues involving chemical exposure - a new-found interest for me after obtaining my MSPH last May.  Basically though, this blog is nothing more than my attempt to consolidate the information out there so that I understand the topic better.  If it helps someone else understand it better too, well than win-win!

Now what I found interesting in all this research (and after 29 posts I have looked at a lot of stuff on this topic) was this graph from the TCEQ:

As a scientist and as a guy who has spent his career looking at numbers to decide what is "dirty" and what is "clean," any time I see a downward trend (my paycheck excluded) I think "good!"  So "bad" ozone levels - which is basically VOCs - is on the downward slide.  And benzene, the most problematic of the VOCs in terms of health issues, is also on the decrease as well.  And at the same time, oil & gas production is on the rise.  Go figure.

Now you can explain this away anyway you want, economic downturn, manufacturing going to China, pollution control, increase enforcement, but the fact is, with an increase in oil & gas production in the Barnett Shale area, the air has not become more contaminated with these two dominant pollutants of concern.  Which means that the foot print of a well maintained oil & gas production site poses a minimal impact on air quality in this area based on the data we have....and we have a lot of data to bolster this.

I have read all of the reports referenced by all the parties involved.  I have looked up the procedures and read them.  I have looked up the citations and the references.  I have checked and double checked the calculations.  All of this has been done in an effort to either support or dismiss the scientific work presented.

I know - because I have been there and I work with hundreds of different people from different disciplines and organizations - that we humans make mistakes.  Sometimes through sheer incompetence (example), others because the issue was illusive, subtle, or extremely nuanced (i.e. Tedlar bag artifacts).

The whole point of this blog is to look at complex topics, tear them apart, and try to understand all the different things that impact it and give it substance and weight.  What you read here is not my expertise but my journey towards an understanding while I try to comprehend it better.  Because it interests me, it may be of interest to someone else as well, or, it may be helpful to someone trying to better understand an issue.

It may seem after 29 posts that I am being hypercritical of the work performed by Alisa Rich and Dr. Sattler.  I am not.  My critique is about the method and data they used, the assumptions they made, and the inferences drawn by these two professionals for their clients including the town of Dish, Texas and the FWLN.

Alisa Rich holds a Master in Public Health (MPH) and is working on a Ph.D.  For me to consider the possibility that she is not aware of the fundamental difference between an ESL and an AMCV is to say UNT's MPH program is derelict in it's course work.  And if that's not the case then what is it?  The reports she wrote for her clients ignore the basic principle of assigning and describing risk - something she should have learned while obtaining her MPH as well as during her time perusing her Ph.D.

And what about Dr. Sattler?  She is an engineer.  But not just an engineer, but a PE!  That's the top of the heap in terms of the ability to show competence and good engineering principles.  And to top it off she is a professor at a major Texas university.  To build a model around one single sample, to estimate an exposure concentration two miles away that is three times higher than the PEL, to ignore non-Gaussian dispersion in the other samples collected at the same time, and to continue using an ESL - derived for odor no less - for ambient air samples because you don't know if  "the technically competent people [at TCEQ] were involved in this [AMCV] decision."  How can a person with this standing and education and credential allow such questionable work to pass as valid?

And because of the work of these two environmental professionals, the FWLN presented their report to the FWISD recommending set-backs of one mile based on the potential for receptors - children - in this area to be exposed to carbon disulfide and carbonyl sulfide at levels way above those deemed harmful for an adult worker.

And to bolster this report as valid, two additional Ph.Ds signed on as part of the "team of scientists and experts – Dr. Ramon Alvarez, Dr. Melanie Sattler, Dr. David Sterling, and Carl Weimer – who donated their expertise and time to the League to produce this report."  These two Ph.Ds aren't slacks either.  Dr. Sterling is the "Chair of Environmental and Occupational Health, University of North Texas Health Science Center, Fort Worth."

So why should Deborah Rogers - the FWLN "liaison between the League and the team" - question what this team produced?  Why should anyone who reads the FWLN report question its validity with these experts on board?

And therein lies the problem.

If I have not made my case after 29 posts, well I don't know what more I can offer.  I can defend my critique of their work, its all there in cyber black and white.  If I am wrong, then show me so that I may correct it.  That's the intellectuality honest thing to do.  Right now the ball is in Dr. Sattler's court for her to defend her work as valid.

Which is why I took her up on that challenge she made in the Deposition:
I think my work stands up to anybody that has expertise in dispersion modeling.  If anybody was criticizing it, they probably didn't have --well, it wouldn't surprise me to see somebody without a scientific background criticize it, because they probably wouldn't understand it.
Well I don't have expertise in air dispersion modeling, but my white lab coat has allowed me to look at it objectively and question the premise of backing in an ambient air concentration to derive an emission rate.  Oh, and I do have the scientific background to criticize it because after 29 posts, you should see that I do understand it.

So here it is, once more:
In the Town of Dish, Texas report prepared for by Alisa Rich, the six samples collected and used to calculate the emission rate which was then used to develop the plumes, do not show Gaussian dispersion in the ratio of contaminates analyzed.  Explain?
In the FWLN you produced a model - Plot 1 - for carbon disulfide that is based on one sample collected on one day.  Please explain how Plot 1 can be determined to be representative of all the oil & gas production sites in the Barnett Shale area?
In the Town of Dish, Texas report, the model you produced is based on identification and quantification of carbon disulfide identified by the lab as a TIC.  In the FWLN report, Plot 1 utilizes a carbon disulfide identification and quantification that is identified by the lab as a TIC.  In the FWLN report, Plot 2 is based on a carbonyl sulfide identification and quantification from a sample collected in a Tedlar bag which is known to produce artifacts of carbonyl sulfide.  How confident are you in these concentrations you used to "back in" to your model to determine the emission rate?  What is the basis you use to support their validity?
In order for the Gaussian dispersion model to work for a year's worth of plumes, the emission rate must stay constant.  Please explain how in Plot 1 of the FWLN report, at two miles from the source the air concentration for carbon disulfide could be at three times the OSHA PEL without causing illness, death, or a significant odor problem in and around the source if that is, indeed, the correct emission rate?
You assume in all your models, including FWLN, that all of the contaminant found in the ambient air is coming from the O&G source.  When looking at other scientific papers where an ambient air sample is "backed in" there is an upwind sample collected so that background contamination - not from the source - is not included (subtracted out).  On what scientific basis does including background levels of contaminants in your emission rate calculation fall under?
That's all Dr. Sattler needs to respond to.  Five appropriate and scientifically-based questions dealing with her work.

If these are non-issues, well you got me on that.  But I think they are real issues that need to be addressed in order to conclude that the need for a one-mile set-back is valid.  Even Dr. Sattler acknowledged this in her Deposition:
I just think with this [FWLN] study imminently going to provide results of lots of data, that it's prudent to -- to get the results of that study, so that if it recommends a setback distance of 400 feet, say, from a well, we could try to locate the well 400 feet from wherever it is.
"Prudent" to base the recommendation on the results, which I assume means results that can be held up to scrutiny and critique.

And in case you have no idea why this matters to me, read my post on "why bother writing about this."

And to bolster what I wrote back then, read this story on chronic fatigue syndrome that appeared in the Chicago Tribune (I read it today in Sunday's local paper The Eagle.)

And to further support the reason: (4/3/11) "Health officials struggling to contain a measles outbreak that's hit hard in Minneapolis' large Somali community are running into resistance from parents who fear the vaccine could give their children autism." (1)

So lets put an end to bad science, dubious science, misleading science, incompetent science, and just plain ol' science to bolster an agenda.

Regarding the impact of oil & gas on the air in Barnett Shale....me thinks this dead horse done been whipped enough!


Thursday, March 17, 2011

Air Quality in the Barnett Shale - Part 29: Where should we go from here?

So what do we know?

After reading the Wolf Eagle Environmental reports for the Town of Dish, Texas, after reading the Fort Worth League of Neighbors report to the Fort Worth Independent School District, after reading the TCEQ report on the Health Effects for Barnett Shale, after reviewing the ERG report and BSEEC report regarding air in the Barnett Shale, I can state pretty much unequivocally:
We have enough samples to show that the oil & gas production sites in this area are not emitting contaminants into the air at levels that would pose a health concern, provided...they are adequately maintained.
So the statement from the TCEQ on 10 Sep 2010:
“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.”
 ...is valid today, especially now that we have all this data.  Let's put looking for carbon disulfide and carbonyl sulfide to bed.  It is not a health issue at these low levels, regardless of its source.  The TCEQ seems to also agree with this:

So that is what we do know about these levels of contaminants in the air.  You can continue to sample and it will not add any more substance or weight to what is known already.

But there is something else we know from reading all these reports and memos.  These oil & gas operations do put stuff into the air, especially when they are not properly maintained.  And for that reason, a stronger commitment to reduce the amount of contaminants over all - their environmental 'footprint' - should be the focus for the community and the operators going into the future.

According to the ERG report, based on emission rates calculated through a more sound methodology then "backed in" ambient air sample results, the operations they tested put VOCs, TOCs, and HAPs into the area's air.  And when you multiply that by the number of operations...:

...it adds up.

And when you look at what proper maintenance was able to provide in terms of reduced emissions (Sadlier/Honeycutt: Barnett Shale Study), it becomes apparent that maintenance...:

...and new green completions...:

...must become the industry standard; adopted and wholeheartedly supported by both big and small producers.

So where should we go from here?  Reduce the overall air emission footprint and provide proper and continuous maintenance.

Or as Buzz Lightyear might say:

 "To infinity...and beyond compliance!"

Next Post: Air Quality in the Barnett Shale - Part 30: The End... finally!


Monday, March 14, 2011

Air Quality in the Barnett Shale - Part 28: Why Plot 2 used Carbonyl Disulfide

I was a bit curious as to why the FWLN Report sent to the FWISD included one model for carbon disulfide (Plot 1) and another model for carbonyl sulfide (Plot 2).  Everything up to this point had focused on the health concerns for carbon disulfide.

So I looked closer at the FWLN findings:


And then I looked at the statements printed on a green background in the report:

Okay...so it is all about the carbon disulfide.  So why produce Plot 2 for carbonyl sulfide?

Well duh!  Carbon disulfide was not detected by TO-15 in 46 out of 48 samples (see post) and ASTM Method D5504-08 detected carbon disulfide but had to qualify it as an artifact (see post).

But sample QLA5DC-1 did not have that inconvient qualifier:

So as I'm reading this and looking at the data, my mind is forming the question of; if there is no carbon disulfide detected in the BSEEC samples collected from different sites over different days, and carbon disulfide is the contaminant of concern, why spring carbonyl sulfide into the mix and continue to direct attention to carbon disulfide?

Doh!  Then it hit me.  FWLN is looking at carbonyl sulfide as a "byproduct" of carbon disulfide.  In other words, if you find carbonyl sulfide there must have been - or is - carbon disulfide!  Very astute FWLN!  Only you probably didn't figure on me checking into this, did you?

Yes, indeed, carbonyl sulfide is a "byproduct" of carbon disulfide.  It is produced when carbon disulfide is purposely manufactured.  Lets see what the EPA has to say on this:

You know what else the EPA has to say about carbonyl sulfide?
In the United States, the reported concentration of carbonyl sulfide in the air in rural areas was 0.27-0.80 microgram/m3.  Levels were 1.17 micrograms/m3 in Philadelphia, PA; 1.21 micrograms/m3 in Wallops Island, VA; and 1.37 micrograms/m3 in Lawton, OK.  Reported concentrations of carbonyl sulfide over salt marshes, which are major natural sources, range from about 60 to 180 micrograms/m3, and 14 to 19 micrograms/m3 over the ocean (HSDB 1994).
Well if I am going to be objective here, I need to follow this lead....

Okay...so finally we have something that indicates that we may have an issue with a contaminate in the Barnett Shale area above normally expected background.  And even if you subtract the maximum amount attributed to the artifact, in sample QLA5DC-1 you would still have 105 ug/m3.  That's more than comes off a salt marsh based on the EPA's research.

So lets work with this.  But first we need to make a few points clear.  First the presence of carbonyl sulfide in the ambient air samples collected has nothing to do with carbon disulfide.  And second, the non-detection of carbon disulfide in the BSEEC report using method TO-15 indicates that carbon disulfide is not present.

So the question I can reasonably ask now is carbonyl sulfide a concern? 

Now we are back to the one sample - low n's - issue.  However, carbonyl sulfide was detected above the artifact concentration of 25 ug/m3 in 6 of the 18 samples indicating a possible concentration above the levels found in an urban environment.  So lets assume that 130 ug/m3 (53 ppbv) is a valid number for carbonyl sulfide in the ambient air collected by BSEEC.

What does the BSEEC Report have to say about this:

Looks like the BSEEC folks got their units mixed up. This means that I need to check to see if the AMCV they report is in ppbv or ug/m3.  And guess what I find when I check?  There is no AMCV for carbonyl sulfide.  So where did "1800 ppbv" come from?

Well if I can find the acute ReV that would be the AMCV.  Search....nothing.  What about the RfC?  Checking the IRIS website....nothing, in fact they state:
The health effects data for carbonyl sulfide were reviewed by the U.S. EPA RfD/RfC Work Group and determined to be inadequate for the derivation of an inhalation RfC. The verification status for this chemical is currently not verifiable. No EPA documentation presently exists for this chemical.
Okay...so where did the BSEEC folks get a short-term AMCV of 1800 ppbv?  Well as of right now I have no idea.  I did find a short term ESL value that the TCEQ has derived in a 2008 memo:

So even at 130 ug/m3 (53 ppbv) the amount detected is well below the health-based ESL concentration of 540 ppbv which is 70% of the AMCV.....540 / 0.3...that equals 1800...hey...that's the AMCV the BSEEC folks reported!  

Okay, that gives us a value we can defend as health-based, assuming TCEQs POD and UFs are correct...they seem well supported.  And if the carbonyl sulfide ESL is listed for odor at 55 ppbm, it makes sense that the health-based threshold would be higher:
The short-term ESL is the lowest value of acute odor-, vegetation- and health-based ESLs. (Factsheet)
And at the highest carbonyl sulfide concentration detected - 53 ppbv - that amount is 10 times lower than the health-based ESL of 540 ppbv and more than 33 times lower than the ambient air concentration - the true health-based threshold - of 1800 ppbv.

Y'all double check my math (remember math makes my head hurt) to make sure I'm seeing this right....

Lab reports 53 ppbv...TCEQ states health-based ESL is 540 ppbv...at 540 ppbv the AMCV would be 1800 ppbv...okay...so the carbonyl sulfide in the Barnett Shale samples is well below health based levels.

So what does Dr. Sattler and the FWLN have to say about the carbonyl sulfide in their Report?

Huh?  How could the oil & gas source that produced sample QLA5DC-1 produce an emission rate that produces a model that that predicts concentrations one mile from the source that are "6 times greater than the health benchmark for carbonyl sulfide?"  At 1800 ppbv that would mean one mile out you would have concentrations at 10,800 ppbv?  Even if she incorrectly used the health-based ESL of 540 ppbv, that would show concentrations at 3,240 ppbv one mile from the source.

How is that physically even possible?

Maybe I'm missing something here, how can directly downwind from the source  - 50 -75 feet away - we find an actual concentration 130 ppbv but are able to get a concentration significantly higher further from the source?  How can the calculated emission rate from this actual value extend downwind one mile from the source at a concentration 6 times greater than what produced it at 50-75 feet away?  The same emission rate is being used, correct?  Doesn't Gaussian dispersion show the highest downwind concentrations nearest the source?

Wait a minute...Dr. Sattler is calculating an air concentration in and around the source (red area on her plot) of 655 ug/m3.  That's six times higher than the actual concentration detected within the red colored area around the source.  Now I'm really confused.  I mean the emission rate is staying constant, correct?  And the downwind concentration used to "back in" to obtain the emission rate is 130 ug/m3.  So with that "backed-in" emission rate, you would calculate 130 ug/m3 for the red area.  Yet in Plot 2, that area has a concentration of  655 ug/m3:

Okay...so lets assume Dr. Sattler's maximum 1 hour concentration for carbonyl sulfide is possible.  Would that maximum level pose a health-based concern?
  • The highest concentration Dr. Sattler reports in Figure 1 is 655 ug/m3 or 267 ppbv.
  • The maximum concentration of 267 ppbv is less than the ESL of  540 ppbv.
  • 267 ppbv is less than one half the amount of the health based ESL
  • 267 ppbv is less than six times the health based ambient air concentration of the AMCV.

So why would Dr. Sattler and the FWLN insist that the concentrations one mile from the source could be as high as "6 times the health benchmark for carbonyl sulfide?"  Well lets look at Dr. Sattler's Report on Plot 2 to see what's up about this:
The 1-hour Texas Commission on Environmental Quality (TCEQ) Effects Screening Level (ESL) for carbonyl sulfide is 135 µg/m3; one of the sample concentrations exceeded this level.
.... ah...that's why!  Dr. Sattler is using an odor ESL threshold for the "health benchmark" that is being exceeded:

...and if you will recall, "The short-term ESL is the lowest value of acute odor-, vegetation- and health-based ESLs."

So even if Dr. Sattler's model is correct, the carbonyl sulfide in Plot 2 does not pose and adverse health risk.

And if that is true...and the fact that 46 our of 48 BSEEC TO-15 samples showed non-detect for carbon disulfide, and the two samples that were positive were less than 0.3 ppbv... then there is no health based concern for carbon disulfide or for carbonyl sulfide and the requirement to have a one-mile setback based on the health concerns for these two contaminants is not warranted or substantiated by any of the data provided in the FWLN or BSEEC or ERG reports.

And just so we are clear on this.  The need to provide - or not provide - a setback for O&G operations is not being argued here.  The basis for a one mile setback recommendation due to health-based concerns regarding carbon disulfide and/or carbonyl sulfide is.

And that's all I can really say about this....

Next Post: Air Quality in the Barnett Shale - Part 29: Where should we go from here?


Saturday, March 12, 2011

Air Quality in the Barnett Shale - Part 27: Plot 2; Artifact or the real deal?

Well apparently my attempt at humor and self-depreciation as a means to entertain and inform on the complex - and really dry - world of health, air monitoring, and air dispersion modeling made me look like a fool in the eyes of the FWLN.

So today I am writing my blog while dressed in a long sleeve shirt - with tie - slacks, and my recently polished dress shoes (black to match my belt according to my wife).  And to complete this outfit of visual competency and authority, I have put on my white lab coat, the one with my name embroidered over the pocket!

Hopefully this will get my street cred' back.  You know, nothing says "scientist" like a white lab coat!  In fact, look at what these two guys at Columbia Analytical Services are wearing:

You know what else you can find on their website?  This:

Do you know what "COS" and "CS2" is?  Well since I am wearing a white lab coat, I do.

  • COS = Carbonyl sulfide
  • CS2 - Carbon disulfide
Do those two chemicals sound familiar to you?  Well they do to me:

This post today is only going to focus on Plot 2 of the FWLN report.  Plot 2 is based on the concentration of carbonyl sulfide found in sample QLA5DC-1.  

According to the white lab coats at Columbia Analytical Services, there are two factors in play when a Tedlar bag is used to collect a gas sample.
  1. Concentration range is from ppm to percent (1 percent = 10,000 ppm)
  2. Artifacts may be produced which include carbonyl sulfide and carbon disulfide
If you will recall from my last post, artifact formation is a concern and was noted by the laboratory.  You can read more about issues with Tedlar bags at this website.  And when you look at the BSEEC report you will see that they used Tedlar bags:

...and artifacts were acknowledged:

...and the concentrations were reported as ppbv (which are 1000 times smaller than a ppm):

Now all of this give me pause - and when I am wearing my white lab coat - my scientist-senses start to tingle (analogous to Spider-Man's spider-sense telling him that something is wrong) - or it could just be my cell phone set on vibrate.  Anyway....

So what's the issue?  Seems that Plot 2 which was used in the FWLN shows "multiples [that] were 6 times the health benchmark for carbonyl sulfide."  

And how did they arrive at this "6 times" number?  Using a "backed in" emission rate calculated by Dr. Sattler as described in her 3/7/11 draft report titled "Dispersion Modeling of Carbonyl Sulfide Emissions from a Natural Gas Compressor Station near Lake Arlington."  (link not available).

In this report Dr. Sattler describes the sample concentrations for carbonyl sulfide she used as follows:

...which corresponds to these samples in the BEECE report:

...which are associated with these two laboratory reports:

Upwind Sample

Downwind Sample
Now there are two factors seen above that get my spider-senses....err my white lab coat senses buzzing.  The first is that there is no data qualifier "+" for the carbonyl sulfide quantification as there is for carbon disulfide.

Note 3/14/11: Spoke with the lab this morning.  the reason that there is no qualifier is that they set the highest number attributable to an artifact at 25 ppb.  This qualifier number is dependent on the Tedlar bag used.  So the quantity of 130 ppbv may be only as high as 105 ppbv if the bag did produce artifacts of carbonyl sulfide.  By the way, I just noticed that the laboratory that performed the analysis was the same lab with the white lab coat guys that produced the table I used above.  It's a small world.

Was this an oversight or were they able to exclude the possibility of an artifact in this sample?  The reason that I question this is that the possibility of the carbonyl sulfide being an artifact is noted in samples:
QA52DW-1, EMR3DE-1, EMR3DW-1, CAP4UC-1, CAP4DC2-1, CAP4DC2-DUP1, DLB6U-1, DLB6DE-1, DHH7U-1, CLP9UC-1, XRA4UE-1, and XRA4DE-1
In other words, out of 18 samples 12 identify the carbonyl sulfide as a "possible Tedlar bag artifact."  I will be contacting the laboratory next week to see if I can find out if this was in error.

The second reason I question the validity of these carbonyl sulfide results is that even though the laboratory may feel quite confident in the numbers they have reported for ASTM Method D5504-08 for sulfur compounds:

...while wearing my white lab coat, I went and read the ASTM method.  

...and here is what I found out:

...so we have to assume that both the sampler and the laboratory understood this and took the proper precautions.  Okay, so lets assume they did.  What next?

...well the test is for the gas itself...may not be appropriate for ambient air samples...still...rang is 0.01 ppm...what's that in ppb?....if 1000 ppb = 1 ppm, the range is down to 10 ppb...okay that means the 130 ppb is 130/1000 = 0.13 ppm....kind of close to the method's limit....okay....odd though, the lab's MRL states they can "confidently" go down to 0.0078 ppm.

So once again we are looking at the identification and quantification of a contaminant of concern that is questionable.  I am unsure why ASTM  D5504-08 was utilized in the first place.  Most likely it was to look for sulfur contaminants that are common to natural gas and are not picked up by EPA Method TO-15.  In any case, the use of a Tedlar bag was possibly the wrong choice if carbon disulfide and carbonyl sulfide were to be reported.

Hey....but wait a second....isn't TO-15 appropriate for carbon disulfide and carbonyl sulfide?

And didn't BSEEC run a TO-15 analysis on sample QLA5DC-1 from which Dr. Sattler obtained the quantity for her backed in emission rate calculation for her carbonyl sulfide model shown in plot 2?

...which means there should be a lab report for this sample showing the quantity of carbon disulfide and carbonyl sulfide in the same air on the same day.  And this sample is the correct method and does not have any footnotes calling into question its validity, such as a "possible artifact."  So looking at the lab results for sample QLA5DC-1 we see:

Doh!  They didn't analyze for carbonyl sulfide!  Had they tested for carbonyl sulfide with TO-15 it would have been much more definitive and I could have ended this post right here and now stating that the carbonyl sulfide reported was indeed an artifact. If only it would be that easy....

Still, there is good evidence to think it is - most likely - an artifact.  

The TO-15 method has a detection limit for carbon disulfide of 0.236 ppbv.  The TO-15 results for 46 one hour samples show non-detect and two samples show carbon disulfide at less than 0.61 ppbv.  Now compare this to the detection of carbon disulfide with ASTM Method D5504-08 which found carbon disulfide in 12 out of 21samples with a high concentration of 11 ppbv.

And with my white lab coat on - complete with embroidered name over the pocket - I am able to look at this and boldly state that Plot 2 in the FWLN report is based on a positive identification of carbonyl sulfide and a quantitative amount that is suspect.

And if Peter Parker (aka: Spider-Man) - who himself is a scientist - was looking at this, he too would see not a criminal number, but a number that is suspect.  Call it his spidey-sense, objectivity, or just plain-ol' scientific common knowledge, but that's what any good scientist would conclude - even one that uses self-depreciation and comic book characters to try and drive home his point.

The thing is, we scientists are only as good as the numbers we use and the place we get our data from.  And because of this, the air dispersion model that generated Plot 2 that was based on the results from sample QLA5DC-1, which was derived using ASTM Method D5504-08 from samples collected in a Tedlar bag which - according to other scientists wearing white lab coats - are designed for samples in the ppm range and are also known to produce artifacts of COS and CS2, which - while wearing my white lab coat - I have identified as the two culprits of concern in the FWLN report regarding the need for set-backs; carbonyl sulfide and carbon disulfide, makes the model's predictions of "multiples [that] were 6 times the health benchmark for carbonyl sulfide" suspect.

So what are we left with now?  

If the FWLN report is based on Plot 1 for carbon disulfide which was derived from one single sample collected on one single day (see post) and Plot 2 is based on carbonyl sulfide derived from using ASTM Method D5504-08, then nothing definitive, conclusive, alarming, substantiating, or realistic regarding set-back distance can be ascertained.

Next Post: Air Quality in the Barnett Shale - Part 28: Why Plot 2 used Carbonyl Disulfide

Thursday, March 10, 2011

Air Quality in the Barnett Shale - Part 26: That's a lot of n's!

In my last post I looked at the quality of the data presented in the ERG report and the TCEQ report for air quality in the Barnett Shale.

Looking at how the data was obtained is important to understanding how valid it is.  Along with this is the number of individual data points - or n's - were collected.

Since we are making an assumption, such as the air "does not pose a health hazard" or the air is "2 times above a threshold where irreversible effects can occur" the quality of the data and the representation of the data to what is actually found becomes critical.

Alisa Rich in her report to the Town of Dish, Texas, modeled the air using only six samples - collected on one day - and analyzed with the wrong method, concluding

Dr. Sattler, using one sample - collected on one day - and analyzed with the wrong method, concluded in the FWLN report:

And with these two assumptions, FWLN had enough information to support their contention that the air quality in the Barnett Shale in the Fort Worth Area is significantly impacted:

I contend that because of the lack of representative sampling (too few n's) and the incorrect laboratory analysis (TO-14 instead of TO-15) the data Rich and Sattler generated is invalid and, therefore, their model's predictions are invalid, which makes these types of statements regarding carbon disulfide in the Barnett Shale area false.

So what do we know about the air in the Barnett Shale and the emissions from oil & gas production sites?

Quite a lot, actually.  Both the Barnett Shale Energy Education Council (BSEEC) TITAN Engineering report and the ERG report - referenced in the FWLN report - provide a considerable amount of data (lots of n's). And that data can be supported as valid because the reports can show precision and accuracy (which Alisa Rich and Dr. Sattler cannot).

Now you can choose to ignore the BSEEC and ERG's data, but the only grounds to do so is because you suspect some kind of conspiricy between O&G and them.  Possible, but not very plausible.  A conspiracy to distort, fake, or hide sample data implies both a lot of conspirators who will presumably attempt to conceal what they have done, and a lot of readers who can be successfully persuaded that the data in these two reports have been purposely distorted.

If you think there is a conspiracy by BSEEC and/or ERG to fake this information then you can stop reading now and go back to your land of implausibility.  Like I said earlier in my posts on the air in the Barnett Shale area, I assume that the data provided by Alisa Rich and Dr. Sattler has not been purposely manipulated.  It may be invalid, but I don't think it has been faked, tainted, or manipulated.  The same is true for BSEEC and ERG's data.  I assume it to be truthful and honest.

The BSEEC tested the air over four time periods in June, at nine (9) different locations.  EPA Method TO-15 found the following results for 93 samples (n's) of carbon disulfide:

The BSEEC report identified the following concentrations for carbon disulfide and carbonyl sulfide tested using ASTM Method D 5504-08 for sulfur compounds .  Please note that the number "4" by the quantity indicates:

Which means that it may have come from the bag itself and not from the air sampled:
A significant factor in the selection of filter media used for air sampling is the formation of artifacts due to the sorption of sulfur and nitrogen oxides on the filter. These artifacts can erroneously increase measured particulate concentrations. (1)
Here is what the BSEEC reported:

Thats over 21 samples (n's) for carbon disulfide, and of these samples, nine (9) were non-detectable.  Assuming that the concentration reported for this method were not artifacts, the highest concentration of  carbon disulfide was 11 ppbv.  

It should also be noted that only Tables 10, 14, 20, 23, and 26 showed a higher concentration of either contaminant downwind as compared to upwind ("D" = downwind in sample number)  The highest carbon disulfide concentration, 11 ppbv, was found in the upwind sample!

So the BSEEC report brings us a total of 114 n's for carbon disulfide.

Now lets look at the ERG Report, also referenced in the FWLN report.  ERG sampled nine (9) unique O&G sites plus one site designated as background:

At these sites a total of 92 detections for carbon disulfide were found with an average concentration of 0.243 ppbv and the highest concentration detected as 1.64 ppbv for a 24-hour sampling period:

So what do we know about the concentration of carbon disulfide in the air around oil & gas production facilities in the Barnett Shale?

Out of 206 samples (n's) the maximum concentration of carbon disulfide found in the air in the Barnett Shale area was no higher than 11 ppbv.

If Dr. Sattler's contention is true that from her one sample used in the FWLN was found to produce an emission rate that could produce up to 78 ppm (that's 78,000 ppb).  At the backed in calculated emission rate that she believes is emitting carbon disulfide, don't you think we would have seen concentrations above 11 ppbv in at least one of the 206 samples?

And the reason we are not seeing anything higher than 11 ppbv (or 10.8 if we assume the TIC she reported is accurate) is for one simple reason;  you cannot back in an ambient concentration into a Gaussian air dispersion model without placing directly downwind from the site and subtracting the upwind concentration from the result: (2)

The presence of carbon disulfide in the Barnett Shale area, regardless of source, is consistently way below the permitting ESL and the health based AMCV.

206 n's tell us this...and that's a lot of n's!

Next post: Air Quality in the Barnett Shale - Part 27:  Plot 2; Artifact or the Real Deal