CPANA today received the first set of results from a planned year-long screening of air quality before natural gas drilling takes place.
We are using an independent laboratory to analyze diffusion tubes which are exposed to the air near one of the proposed future drill sites. By getting a good benchmark of current air quality, we hope to be able to detect any changes in quality after drilling and gas production begins.
Initial Results:
The tube was analyzed for Benzene, and the top nine other volatile organic compounds (VOCs) found.
Benzene was below the limits of detection, which is 3.9 ng for the tube. According to the lab, this limit would be equivalent to about 0.076 parts per billion (ppb), which is well below the 1.4 ppb long-term effects screening level, and the short-term 54 ppb ESL. Because benzene was not detected, we know that our levels are below 0.076 ppb.
Only three other compounds were detected, and none exceeded long term or short term effects screening levels (ESLs):
- 1R-.alpha.-Pinene at 0.15 ppb (Long term ESL is 1.0 ppb)
- Toluene at 0.03 ppb (Long term ESL is 330 ppb)
- m/p- Xylene at 0.02 ppb (Long term ESL is 42 ppb)
Toluene and Xylene are both solvents used in a variety of products, and part of the BTEX (Benzene, toluene, ethyl-benzene,xylene) quartet of hazardous chemicals that are sometimes emitted from natural gas operations.
According to an EPA fact sheet on Toluene, automobile emissions are the principal source of toluene emissions in ambient air. According to CDC, xylene is also found in automobile exhaust, and comes from industrial sources. The CPANA air sampling station for this test is located away from idling automobiles and well setback from nearby streets.
Pinene is a natural compound produced by pine trees, some of which surround the testing site.
Sampling Method
Samples are taken by using a diffusion tube exposed to the ambient air in a locked, ventilated box near the proposed drill site. Diffusion tubes are stainless steel tubes containing a sorbent material that passively soaks up air contaminants over a specified time period. The tubes are maintained with a strict chain of custody, installed under seal and witnessed by at least two CPANA board members. The completed sample is mailed to an analytical laboratory with no ties to any of the local natural gas operators.
The initial sample was taken from 6/23/2010 - 7/24/2010. Overall MOU (margin of uncertainty) is +/- 16.8%. The laboratory is certified for the analytical work, but ppb numbers take into account exposure times provided by CPANA, and for which they have no control.
Laboratory results are attached.
