By Ronald E. Bishop, Ph.D., CHO, March 26, 2012
Observations on Selected USEPA Summaries of Well Water Analysis from Dimock, Pennsylvania, 2012.
I have reviewed biological and chemical analysis summaries of Dimock homeowners’ wells identified by the USEPA as HW-02, HW-04, HW-06, HW-08a, HW-12 and HW-17. These are my observations:
The methods used to determine coliform and heterotrophic bacteria were very poorly performed: results from ten out of the twelve analyses reported were either rejected or clearly inconsistent. Therefore, they provide no basis to assess the presence or absence of microbes in the well water samples.
Minimum detection limits for glycol ethers and other detergents were unacceptably high. Therefore, no conclusions regarding pharmacologically significant concentrations of glycol ethers (particularly the endocrine disruptor 2-butoxyethanol) can be made from these results.
Methane concentrations were reported at over 7 parts per million (ppm or mg/L) in 4 of these wells: HW-02 (18 mg/L), HW-06 (23 mg/L), HW-08a (15 mg/L) and HW-12 (52 mg/L, a detonable concentration after outgassing at surface temperature and pressure). Ethane: methane ratios in these water samples ranging from 0.035 to 0.038 implicate thermogenic origins for these gases. Therefore, these reports provide evidence that nearby access to deep gas reservoirs may have negatively impacted the quality of water in these wells. Any suggestion that water from these wells is safe for domestic use would be preliminary and inappropriate.
Non-zero concentrations of polycyclic aromatic hydrocarbons (PAH’s) were reported in HW-02, HW-04, HW-06 and HW-8a; they included anthracene, benzo(a)pyrene, benzo(g.h.i)perylene, dibenzofuran, phenanthrene and pyrene. These PAH’s are significant carcinogens from chronic exposure at any concentration. Further, non-zero concentrations of chloroethane and chloromethane were found in HW-12, the water well with the highest ethane and methane concentrations of all those reported here. Although not classifiable as human carcinogens, these componds may harm selected internal organs. Therefore, the use of water from these five wells without further testing to establish seasonal variation or biochemical safety would be inappropriate.
Supra-MCL levels of arsenic, fluoride, lithium and sodium (in addition to ethane and methane) were found in well HW-06. This particular combination of analytes would be consistent with the introduction of gas drilling / hydraulic fracturing additives into this water well. Therefore, further study of this possibility is warranted.
In summary, the decision of the USEPA to certify these six wells in Dimock, PA as “safe” was, in this reviewer’s opinion, premature and inappropriate for at least five of the six wells reviewed here.