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Environmental
Assessment -- Chloride Testing
The
chloride test strips come from Hach (www.hach.com
-- search for chloride test strip) and what we use are the
low range test strips (30 mg/l to 650 mg/l). The strips have
a scale on them with an orange strip in the center that goes
nearly to the top. The orange strip turns white in response
to chlorides and all you have to do is read from the scale
how high the change occurs to get the concentration.
We
do water tests two ways -- either by getting a sample in a
container or by clipping the test strip onto a wood shim (from
Lowes or some other builders' supply) and sticking the shim
in the mud so that the bottom of the test strip is in the
water but not touching mud.
It's
important when testing a sample that the whole test strip
not be immersed. When the test is completed a black line appears.
That part of the test strip needs to be kept dry. We use binder
clips to help hold the test strip on a shim or on a container.
Soil
tests are a little more complex. We use plastic Ball freezer
containers from the grocery store -- small ones for soil samples
(purple lids) and larger ones for testing (green lids). At
home we dump the soil sample from the purple lid container
into the larger container and mix with an equal amount of
distilled water (also from the grocery store). The mixture
is shaken for 30 seconds and then let sit. Some samples settle
fairly quickly, some take a day or more. The test strip can't
be set in mud or silt or the crud will clog the titrator.
We use a clip to hold the test strip at the right level.
It
can take a while for a test using a test strip -- a few minutes
to what seems like an hour. Generally if there are high chlorides
the test is faster. The only issue with the test strips is
that they must be stored at 86 degrees or less. For summertime
we're putting just a few in a pill bottle and keeping that
in an insulated bag when we're out at a site.
Counting
shipping and test strip, a test costs about $1.40. Chlorides
are great for us since there are criteria for waste management
and water quality (both domestic and rivers and such) in West
Virginia. We figure if a soil test is over 30 mg/l then there
is probably contamination.
The
photographs shown below are from the sampling for the Environmental
Assessment for 47-079-00731 and 47-079-01492.
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A
chloride test strip held to a wood shim by a binder
clip. The shim is standing in a large puddle. A sample
number is written with a Sharpie on the shim.
What
looks like an oily sheen on the puddle is a type of
bacteria.
This
is sample W4, >650 mg/l.
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When
tapped with a stick, the bacteria's sheen breaks up
into blocks like this.
This
type of bacteria is attracted to water with high iron.
High levels of iron are found in brine and oil and gas
well waste.
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This
wood shim with a test strip is in a small stream.
This
is sample W3, >650 mg/l.
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We
collected a sample of water going into a culvert and
used a binder clip to hold the test strip to the cup.
The thick black line on the test strip shows that the
test is done.
This
is sample W5 and the result was 57 mg/l.
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Soil
samples are collected and recorded. Testing is at home
after mixing with distilled water.
This
is the fill slope showing drainage from the pit above
and to the right of Molly. Soil sample S6 (<30 mg/l)
is on the fill slope and away from visible drainage
signs.
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Sources
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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