This
was correspondence written in response to a discussion where a legislative body
wanted to ban the spread of natural gas brine of roads.
This issue needs to be looked at objectively as with any
other decision making process regarding the management of wastewater. It
means looking at permit limits or standards; in this case, specifically the
role of standards for human health protection. Standardized values remove
emotional subjectivity from the decision making processes and rely on
scientific values. As with any issues that rely on science, there have been too
many decisions are being made on emotion and not facts.
Impacts to Health are the Reason that the use of brine
is questioned
As with any decision regarding chemical exposure and
human health the principles of risk assessment need to be applied; in this case
a simple exposure assessment should be included in the discussion. This part of
the discussion has been largely ignored
by people opposed to the spreading of brines.
An risk or an exposure assessment would seek to answer
question posed by most people – What will be the impact of the brines on my
health? In a more toxicological mind frame the question would be “what is
concentration of the chemicals of concern at the point of ingestion? - And at
concentration would there be an impact to health? The answer to this question
should guide the conversation, instead on the abstract discussion on the
“innate” toxicity of the produced water.
Travelling through the environment changes chemicals
If the brine is spread on the roads then the
concentration should calculated after a fate and transport model is run to
determine what the concentration of the chemicals would be at the point of
ingestion (in this case a drinking water well). From the general discussion on
this topic that has been prevelant at the informational forums, there is an
erroneous assumption that the chemical concentrations of brine would NOT change
from that in the produced water (average values can be found in various
literature sources). This is categorically not true. This assumption
completely negates the natural processes and the science behind environmental
distribution, biodegradation, soil adsorption, volatilization and all the other
physical and chemical reactions that these assumed “toxic” chemicals would have
to go through before they enter into the groundwater and travel the
distance(long or short) to someone’s water well where there is a potential of
for consumption.
Common conclusions about gas brines ignore facts
Other issues not taken into account are,
- Dilution factor associated with the precipitation (snow) or ice. In some cases it can be as high as 500 to 1. This does not assume that dilution is a solution but a diluted solution has a better chance for the body to metabolize and eliminate efficiently.
- Biodegradation of some of the components that have the potential to be found in the produced water; for example the biocides and some of hydrocarbons (biodegradation natural or by ambient micro-organisms). Incidentally the same biocides are used in cooling towers and then ultimately discharged into surface waters.
- Volatilization of the dilute concentrations of some of hydrocarbons off the road surface.
If we used the kind of decision making process and
thinking that is currently occurring with the misinformation circulating, then
it would wrong for any type of permitted industry or manufacturing plant to
release any type of chemical compounds to surface water because of the innate
“toxic” nature of some of the chemicals contained in certain industrial
wastewater streams. It would also be unacceptable for anyone to drink coffee considering
how innately toxic caffeine is with a LD50 of about 200 mg/kg while the biocide
DBNPA (used in hydraulic fracturing) has an LD50 of 290 mg/kg
If the question is the concentrations of the chemicals
in the brine, then that would vary from source to source. How about using the
worst case scenario to determine the potential health impact? Take the
concentration of the most potent chemical of concern, its dilution off the road
surface, biodegradation etc. and a person’s water well, 10 feet off the roadside
and calculate the potential impact to get a better understanding of what really
happens to these brine and road salt once it is spread on the roads.
Some interesting reports
REPORTS:
This one titled: An Investigation of Naturally Occurring
Radioactive Materials (NORM) in Oil and Gas Wells in New York State April 1999
and revised in 2004.
“While NORM-contaminated equipment has been a concern in
North Sea oil well drilling, the results of this investigation show that NORM
contamination of New York State equipment is insignificant. New York State well
drilling equipment and wastes do not constitute a health risk for the State’s
residents nor present a potential degradation of the State’s environment.”
Granted this report did not address shale brines but it
looked natural gas brines in New York State. It used (7.4 pCi/g) resulting 3
mR/year as the worst case scenario and found it to below the 10mR/year standard
in from the TAGM.
Information on the Quantity, Quality and Management of
Water Produced during Gas Production
“The quality of produced water from oil and gas
production is generally poor, and in most situations, it cannot be readily used
for other purposes without prior treatment.”
Does not discount uses but recommends prior treatment.
This Committee discounts all use.
Has some interesting facts on brine usage in Michigan
albeit it old information
This correspondence does not agree with or disagree with
the use of brines on the county’s road, all it does is present some of the
logical thought that goes into determining whether a chemical (brine or road
salt) would have an impact on human health of not.
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