As we've reported before, CPANA is in the process of conducting a year-long pre-drilling air quality benchmark study. We recently received results from the third month of monitoring.
CPANA uses a stainless steel sorbent tube placed in a secured location outdoors in Southern Lewisville, just down-wind from a future drill site. The tube passively soaks up contaminants from the air and is exposed for about a month. After exposure, the tube is sealed up and shipped to a laboratory where it is analyzed by thermal desorption - gas chromatography / mass spectrometry. The group is looking for the concentration of Benzene, and the top 9 other volatile organic compounds (VOCs).
The following compounds and concentrations were found for the sampling period of 9/19/2010 - 10/18/2010:
- Benzene was not detected. The limits of detection for this sample puts benzene below 0.05 ppb.
- Isopropyl Alcohol was detected at 0.23 ppb. This is standard rubbing alcohol used for medical procedures and as a household solvent or astringent. It can also be used as a fuel additive.
- Acetic Acid was found at 0.15 ppb. Commonly known as vinegar, but also used in industry as a feedstock. It can be found in nature as a fermentation byproduct of fruit spoilage. It may be used as a household cleaner or used in food preparation.
- Cyclohexanone was found at 0.13 ppb. A chemical precursor to the manufacture of nylon, this compound is a product of the oxidation of cyclohexane. LTESL (health) = 20ppb, under review.
- p-Xylene was found at 0.10 ppb. This solvent is similar to Benzene, but with two additional methyl groups added. The ortho, meta, and para isomers (the o, m, or p prefix) indicate where on the molecule the methyl groups are added. According to CDC, xylene is also found in automobile exhaust, and comes from industrial sources. LTESL (health) = 42 ppb for all 3 isomers.
- Pinene was found at .07 ppb. (This is a natural compound from pine trees, which are located near our sample box)
- Dodecane was found at 0.03 ppb. This is a 12 carbon alkane hydrocarbon that is a component of diesel and aviation fuel. LTESL is 350 µg/m3
- Isocyanato Cyclohexane was found at 0.03 ppb. A yellowish liquid with an irritating odor. Insoluble in water. Flash point 127°F. Very toxic by inhalation, skin absorption and ingestion. Used to make pharmaceuticals and agricultural chemicals. LTESL (health) is 0.4 ppb.
- Tridecane was found at 0.03 ppb. This is a 13 carbon alkane hydrocarbon that is a component of diesel and aviation fuel. It is also naturally produced by some stinkbugs as a defense. (Note that our sample box has screen to keep insects out, and we check for insects when we change tubes). LTESL is 350 µg/m3
No other compounds were detected in this sample. Concentrations are given in parts per billion (ppb). Overall MOU (margin of uncertainty) is +/- 16.8%. Laboratory results are attached.
