Environmental Engineering Reference
In-Depth Information
leads to claims that problems caused by well failure or accidents involving
trucks carrying fracking chemicals are not ascribed to fracking.
38
One study of aquifers overlying the Marcellus and Utica shales in the
north-eastern US found ''systematic evidence of methane contamination of
groundwater associated with shale gas extraction''.
39
A review by Associated
Press (AP) of complaints about well-water contamination in Ohio,
Pennsylvania, Texas and West Virginia found many confirmed cases of water
pollution from oil and gas drilling. AP concluded that the review ''casts
doubt on industry suggestions that such problems rarely happen''.
40
Methane and fracking fluid may escape/contaminate water via a number
of different routes:
Migration down naturally occurring fractures in the rock or via exten-
sion of fractures created by fracking or via nearby abandoned wells;
Leaks via well-casings that have been inadequately completed or
which have subsequently failed (probably a greater risk than that
above); and
Leaks or spills of fracking fluid or 'produced water' above ground.
If there is a risk of contamination, what chemicals could be involved? A
major problem is that there is limited data on the chemicals that have been
used for fracking. This is because US law excludes fracking from federal
regulation by the Environmental Protection Agency. However disclosure is
required by some US states and some companies are posting the com-
position of the fracking fluid they are using online. In the UK, companies
will be required to publish the contents of fracking fluid.
One study in the US looked at 944 products containing 632 chemicals used
in natural gas operations and assessed the health impacts of 353 chemicals.
According to the authors ''more than 75% of the chemicals could affect the
skin, eyes, and other sensory organs, and the respiratory and gastrointestinal
systems. Approximately 40-50% could affect the brain/nervous system, im-
mune and cardiovascular systems, and the kidneys; 37% could affect the
endocrine system; and 25% could cause cancer and mutations''.
41
A study reported in the Journal of Endocrinology analysed water samples
taken from sites near active fracking wells in Garfield County, Colorado, and
from control sites in the same and an adjoining county.
42
The study found
that the samples from sites near active fracking wells contained higher levels
of endocrine-disrupting chemicals that could increase the risk of repro-
ductive, neurological and other diseases.
The fracking industry claims, rightly, that the chemicals used are only a
very small percentage of the total volume of liquid that is pumped under-
ground. However, given the volume of water used in fracking, this still
represents a very large quantity of chemicals. Fracking one well uses between
9 and 29 million litres of water, so even if chemicals account for only 0.5% of
the water volume, this means between 45 000 and 145 000 litres of chemicals
used per well.
