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.

Interesting....

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.


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