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

Simple, cost-effective techniques are needed for land
managers to assess the environmental impacts of oil and gas
production activities on public lands so that sites may be
prioritized for further, more formal assessment or remediation.
These techniques should allow the field investigator to extend
the assessment beyond the surface disturbances documented by
simple observation and mapping using field-portable instruments
and expendable materials that provide real-time data. The
principal contaminants of current concern are hydrocarbons,
produced water, and naturally occurring radioactive materials
(NORM). Field investigators can examine sites for the impacts
of hydrocarbon releases using a photoionization detector (PID)
and a soil auger. Volatile organic carbon (VOC) in soil gases
in an open auger hole or in the head space of a bagged and
gently warmed auger soil sample can be measured by the PID.
This allows detection of hydrocarbon movement in the shallow
subsurface away from areas of obvious oil-stained soils or oil
in pits at a production site. Similarly, a field conductivity
meter and chloride titration strips can be used to measure salts
in water and soil samples at distances well beyond areas of
surface salt scarring. Use of a soil auger allows detection of
saline subsoils in areas where salts may be flushed from the
surface soil layers. Finally, a microRmeter detects the
presence of naturally occurring radioactive materials (NORM) in
equipment and soils. NORM often goes undetected at many sites
although regulations limiting NORM in equipment and soils are
being promulgated in several States and are being considered by
the USEPA. With each technique, background sampling should be
done for comparison with impacted areas.
The authors examined sites in the Big South Fork National
River and Recreation Area in November of 1999. A pit at one
site at the edge of the flood plain of a small stream had
received crude oil releases from a nearby tank. Auger holes
down gradient from the pit showed the presence of anomalous
concentrations of VOCs at depths of 3 feet for a distance of
about 50 feet. PID readings at other sites showed 1) one
reclaimed site where hydrocarbon biodegradation was incomplete;
2) one reclaimed site where biodegradation had left no traces of
VOCS; and 3) two sites where traces of substantial offsite
migration of hydrocarbons occurred. Produced water salts at one
site have migrated many 100s of feet downvalley from the area of
salt scarring and tree death adjacent to the pits. Naturally
occurring radioactivity (NORM) at most sites was at background.
One site showed anomalous radioactivity related to NORM in a small brine pit. Some of this NORM has moved downslope from the
outlet pipe to the pit.