HISTORY
AND GEOLOGY OF THE NAVAL INDUSTRIAL RESERVE ORDNANCE PLANT (NIROP) NATIONAL
PRIORITY LIST SITE, FRIDLEY, MINNESOTA
Friday, February 27th @ 4pm
Davis Hall room 308 By: Harvey D. Pokorny, PGNAVFAC Mid-Atlantic, Great Lakes, Illinois
The 83-acre Naval
Industrial Reserve Ordnance Plant site (NIROP) lies approximately 700 feet
east of the Mississippi River in Fridley, Minnesota. The U.S. Navy and
its contractors produced advanced weapons systems at the industrial National
Priority List (NPL) site from 1940 to 2012. In 1981, trichloroethene (TCE)
was discovered in on-site groundwater wells and in the City of Minneapolis
drinking water treatment plant intake pipe, located within the Mississippi
River approximately 4,900 feet downgradient from the NIROP site. In 1983, investigations identified pits and
trenches in the "North 40" area of the NIROP site where drummed
wastes had been disposed. Contaminated soil and drums have since
been excavated from the "North 40" area and properly disposed
off-site.
In
August 1988, a remedial investigation and feasibility study revealed that impacted
groundwater originating from the site was flowing towards the Mississippi River
at TCE concentrations of up to 10,000 parts per billion (ppb). In contrast,
the Safe Drinking Water Act sets the maximum contaminant limit (MCL) at five
ppb PCE for potable water. Concentrations of TCE in area monitoring
wells adjacent to the river have since decreased to levels ranging between non-detect to
150 ppb, and TCE has not been detected in the city of Minneapolis
water intake pipe since the 1980s.
On September 28,
1990, EPA issued a Record of Decision (ROD) that presented a
cleanup remedy to hydraulically contain the groundwater contaminant
plume using an extraction well system. The Navy conducts cleanup
and groundwater monitoring action at the NIROP site through a partnering
arrangement with the U.S. EPA and the Minnesota Pollution Control Agency
(MPCA).
Groundwater treatment has been ongoing at NIROP since
September 1991 and continues today. Additional extraction wells were installed,
replaced, and/or taken out of service over the years, along with treatment
system upgrades designed to maximize system performance and gather additional
information. More than 4.3 billion gallons
of groundwater have been treated since 1991, resulting in a recovery of over 40,000
pounds of TCE. The treatment system is removing
contaminants between 25 and 100 feet in depth, but will take excessive time for
groundwater to reach cleanup goals at the current pace.
Groundwater remediation at the site is complicated by
glacial drift sediments intertwined with fluvial terrace channels on the east
and stacked channels closer to the Mississippi River edge. The
Navy is completing a source investigation featuring vertical sampling at 36
locations. A preliminary overview of
investigation results will be presented along with the geologic framework of
the site.
Biography
Harvey D. Pokorny, PG
Mr. Pokorny, a Professional
Geologist, is a native of the Chicago area.
He spent the initial 13 years of his geological career in the oil and
gas business working as an exploration geophysicist/geologist. Work was performed for independent oil and
gas firms both as a consultant and employee.
Since 1989, he has been
employed in the environmental business as a geologist/project manager. He has conducted Phase I environmental
assessments through completion of remedial action on multiple sites in multiple
states. The past seven years were spent with an emphasis on environmental oversight of construction projects. This work continues with his present
employer, NAVFAC Mid-Atlantic, located at Naval Station Great Lakes.
Mr. Pokorny’s area of expertise
is the geological sciences and application of same to the environmental
industry. He brings in a background of
chemistry and regulatory compliance to project management issues.
He received a Bachelor of
Science (1970) and Master of Science (1972) in Geology from Northern Illinois
University. He trained in the environmental sciences at
Colorado School of Mines. He is a
licensed professional geologist in Indiana and Illinois, a Certified Geologist
of American Institute of Professional Geologists, and an active member of the
American Association of Petroleum Geologists.
