DOW Insider
DIVISION OF WILDLIFE INVESTIGATES SOURCE AND
CONTROL OF CONTAMINANT IN SEPTIC SYSTEM
The Division of Wildlife has temporarily suspended chronic wasting disease (CWD)
sampling activities at its Wildlife Health Laboratory in Fort Collins until
the source of a contaminant in the septic system is confirmed. In the
course of securing approval for an Underground Injection Control (UIC)
permit for its laboratory, the Division has learned that the disinfection
process being used to clean laboratory surfaces in conjunction with the
collection of samples for CWD testing may be the cause of elevated levels of
a chemical known as Di (2-ethylhexyl) Phthalate (DEHP).
Elevated DEHP levels in laboratory waste water were first detected during
routine water quality tests performed by inspectors from the U.S.
Environmental Protection Agency (EPA). The finding was a surprise because
the disinfection process suspected to be the source of DEHP is also used by
other laboratories doing similar work and has been approved by EPA.
“From the water testing data provided by EPA and our own follow-up
assessments, it seems pretty clear that the use of the disinfectant is
linked to the DEHP levels,” said Dr. Laurie Baeten, WHL veterinarian. “We
suspect the disinfectant is reacting with the spraying equipment, the paint
on the floor or something else within the lab to generate the DEHP.”
DEHP is a chemical in the phthalate family. These compounds are found in
common products such as polyvinyl chloride (PVC), rubber, cellulose and
styrene. According to the EPA, DEHP may have potential adverse short- and
long-term health effects when ingested at elevated levels in drinking
water. However, DEHP has been found to adhere to soil and sediment so is
not likely to leach into groundwater, and it is readily degraded by microbes
within a short period of time.
The Division already has taken several actions to lower DEHP levels in the
septic tank, based on the pattern of DEHP concentrations found at different
steps during the lab disinfection process. Water levels in the contaminated
tank are being maintained at levels that prevent further discharge into the
leach field. Supplements have been added to the tank to promote microbial
activity. In addition, laboratory activities that require use of the
disinfection procedures suspected to be releasing DEHP have been temporarily
suspended. Testing of wastewater taken from the septic tank within a week
after implementing these modifications showed that DEHP levels already had
dropped by about 85%, but were still above the EPA’s acceptable maximum
contaminant level (MCL). Once the DEHP levels in the septic tank fall below
that level, Division officials hope that the lab will be able to resume
discharges into the associated leach field.
The Division is also in the process of installing lysimeters around the
leach field associated with the septic system. Lysimeters are devices
placed in the soil that will allow the collection of fluids passing through
the soil. This will allow the Division to measure DEHP levels in the leach
field and downgrade groundwater.
Once the source of DEHP is more clearly understood, the Division plans to
modify its methods for CWD sampling and decontamination in order to
eliminate further production of DEHP from the laboratory. Division
officials hope to resolve this issue soon so that sampling activities can
resume before deer and elk hunting seasons begin next fall.
For more information on the DOW, please visit the DOW’s Web site at:
http://wildlife.state.co.us.
Division of
Wildlife
For more information about Division
of Wildlife go to:
http://wildlife.state.co.us.