CHUCK'S CONOCO
FORT BERTHOLD INDIAN RESERVATION
PARSHALL, NORTH DAKOTA
Parshall
March 2009
ACCOMPLISHMENTS
• Removed 5 USTs
• Excavated 900 yd3 of PCS
• Selected MNA as remedial strategy
• Issued NFA letter
• Abandoned all project wells
• Well closure documents submitted to ND Board of Water Well
Contractors
EPA Region 8 performed this work in partnership with the Three
Affiliated Tribes and with contract support from Avanti Corporation.
PLANNED ACTIVITIES/
FUTURE STRATEGIES
None. The EPA Region 8 UST program has closed the site.
SITE HISTORY
Four of the five underground storage tanks (USTs) located on-site were
removed in 1999. Contamination was found in the vicinity of the former
diesel tank and in areas downgradient from the tank. Approximately 900
yd3 of petroleum contaminated soil (PCS) from the former UST area was
removed. Analytical results from samples collected after the excavation
indicated that high levels of petroleum contamination were still present.
Quarterly groundwater sampling evaluated the seasonal variation in water
table elevations with respect to contaminant concentration, variation in
groundwater flow, and to monitor the effects of natural attenuation to
contaminant concentrations. Following four quarters of contaminant
concentrations below maximum contaminant levels, EPA issued a "No
Further Action" (NFA) letter in 2007. All six monitoring wells (MWs)
were abandoned in 2007.
TIME LINE
4 of 5 USTs removed (5th UST is .
functional heating oil tank)
r
Federal LUST Funding
eligibility determination
• Groundwater
monitoring
r
"No Further Action" letter
issued by EPA * site closed
1994 1995 1996 1997 1998 1999 2000 2001 2002 2002 2002 2003 2004 2005 2006 2007 2008 2009 2010
Feb. Oct. Dec.
Site assessment
discovered
contamination
J
L
6 MWs installed
— 900yd3
of PCS removed
\ CHUCK'S CONOCO LUST SITE
•? EPA Region 8 UST Program Technical Contact | Mr. Raymond Faliskie | (303) 312-6124 or faliskie.raymond@epa.gov | www.epa.gov/region8/ust/
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