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Environmental
Assessment
For
some well sites our reporting includes a broader assessment.
This assessment includes more thorough examination of the
site and surroundings and in some cases tests for chlorides.
More
thorough examination of the site (including outside of the
pad) helps us understand the history of the site and its relationship
to water (including distance and slope). The latter is useful
for analysis when a SPCC violation is possible.
Certain
sites, where warranted, will also have soil (and water when
applicable) tested to note the presence of chlorides. Elevated
chlorides indicates likely pollution from well activities
such as drilling or contamination by brine. We consider chlorides
presence as an indicator of possibly more serious pollution.
Tools
We use a Magellan Spor Trak GPS for recording locations of
important features and/or locations where we take samples.
Chlorides
testing is done using Hach
Quantab chloride titrator strips. We use the low range
(30 mg/l to 600 mg/l) strips. Soil normally has less than
30 mg/l. We're aware of salt scarred sites' soil where no
vegetation grows having 250 mg/l chlorides and higher.
Each
sample is placed in a numbered container and the GPS location
is taken. Positions in relation to the wellhead are recorded
(bearing, distance and location). Sketch maps are also made.
Soil
samples are brought back home and prepared for testing. In
a larger container soil sample is mixed with equal volume
of distilled water and let settle for 48 hours. The end of
the test strip is positioned in the cleared liquid at the
top. Water samples are tested directly, either at the site
or at home.
More
information about how
we test for chlorides is on this page.
Completed
Assessments
We have three Environmental Assessments completed for 2009.
The Environmental Assessment
for 47-039-02026 found elevated chloride in the soil at
three locations: near the separator (a brine leak), at the
location of an earlier brine/condensate leak from the storage
tank, and at an exposed workover pit. The Environmental
Assessment for 47-079-00731 and 47-079-01492 tracks high-chloride
pollution from a closed pit across hundreds of feet until
it reaches the Pocatalico River in diluted form. The Environmental
Assessment for 47-039-05714 investigates exposed pit waste
at a well site drilled several years previously. After chloride
tests were used to sample a number of locations, a soil sample
was taken from the site for laboratory analysis. The laboratory
found elevated levels of arsenic and lead, with the arsenic
exceeding state soil to groundwater screening levels almost
three times and residential soil 41 times higher. Both lead
and arsenic exceed soil screening levels for ecological effects.
At
all of these sites, where the chloride level in soil was elevated,
we found a large number of animal (mostly deer) tracks. Deer
and other animals are attracted to salts and minerals in the
soil and where these occur naturally they are called licks.
Unfortunately, the high chloride waste at natural gas sites
also includes other chemicals which are potentially extremely
toxic.
Sources
Campbell,
Tyler A., et al. 2004. "Unusual
white-tailed deer movements to a gas well in the central Appalachians."
Wildlife Society Bulletin 32(3), pages 983-986.
Otton,
James K. and Zielinski, Robert A. 2000. Simple
techniques for assessing impacts of oil and gas operations
on Federal Lands: a field evaluation at Big South Fork National
River and Recreation Area, Scott County, Tennessee (online
edition). Denver, CO: U.S. Department of the Interior,
U.S. Geological Survey, Open-File Report 00-499.
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