The source of elevated constituents is speculative, but... - Part 4

The UT Arlington webpage describing the study titled "An evaluation of water quality in private drinking water wells near natural gas extraction sites in the Barnett Shale Formation" includes a link to the journal where the paper can be found.  I can't link to it, but it is free to download once you register.

In my last post I was looking at what the paper states and where in the paper the statement is located.  The paper concludes with this:

At a minimum, these data suggest that private wells located near natural gas wells may be at higher risk for elevated levels of constituents than those located further from natural gas wells

I ended my last post asking the question; does the data support that suggestion if you look at all the data available?

On the UT Arlington webpage, Brian Fontenot, the lead author, states:

“This study alone can’t conclusively identify the exact causes of elevated levels of contaminants in areas near natural gas drilling, but it does provide a powerful argument for continued research,”

With that in mind, I am looking at what powerful argument can be made to suggest that private wells located near natural gas wells may be at higher risk for elevated levels of constituents than those located further from natural gas wells?

To start, let's look at this summary table the paper uses after line 706:

Note: Ethanol and Methanol are in mg/L

Now if you recall what they tested for in my last post, you will also notice what they did not find. Here is what line 175 states they tested for:

Arsenic, selenium, strontium, barium, methanol, ethanol, TDS, and volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene, and xylenes (collectively referred to as BTEX) were the primary targets of chemical analyses.

The absence of VOCs is telling. Here is what the congressional report they cite says about BTEX:

The BTEX compounds – benzene, toluene, xylene, and ethylbenzene – appeared in 60 of the hydraulic fracturing products used between 2005 and 2009.  The hydraulic fracturing companies injected 11.4 million gallons of products containing at least one BTEX chemical over the five year period.

Here is what the paper reports on line 192:

We found no evidence of BTEX compounds using both LC-UV-MS and GCMS.

That statement tells me this:  If I sampled 92 individual groundwater wells in the Barnett Shale area.  And these wells were smack-dab in the middle of natural gas drilling boom happening between 1998 and the present, and I found no evidence of BTEX, I would conclude that my down hole activity and removal is not contributing to groundwater contamination.

Additionally, according to this table from the congressional report...

Source

...methanol appears to be the number one chemical component found in hydraulic fracturing fluids used between 2005 and 2009.  According to the table on line 706, methanol is 1.3 - 329 mg/L in the 92 samples compared to 1.2 - 62.9 mg/L in the samples collected where no active wells are located (reference area).

When looking at the results for the samples collected in Figure 2, line 632, it would appear that two samples are showing results considerably higher than the rest.  I have requested (and now received) a copy of the raw data to run median results as these two high values seem to be skewing the averages, which are reported as a mean.  I suspect that the medians for methanol in the active and reference areas are statistically the same.

Nevertheless, if you look at the methanol results, you will see that they do not show a significant difference between groundwater samples collected in unaffected areas.  This, to me, suggests that  "industrial accidents (e.g. equipment failure, faulty well casings, fluid spills, etc.) are not the cause for contaminants in the 92 groundwater samples collected.

But what about the elevated levels of arsenic, selenium, barium and strontium?  Yeah, about those...Okay, that needs to be explained.  But, once again, the absence of the other materials suggests that the contamination of these materials is not from industrial accidents.  That is, if these industrial accidents were commonplace, as the data showing the number of wells contaminated would indicate, we would also see high levels of methanol and BTEX.  In other words, an accident would not selectively release arsenic, selenium, barium and strontium without also releasing the more prevalent chemical components used in the hydraulic fracturing products.

Okay, so that's BTEX and methanol.  Let's look at the levels of arsenic, selenium, barium and strontium they report.

Next post: Part 5


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