Section 319
NONPOINT SOURCE PROGRAM SOCCER STORY
Activated Carbon and Soil Treatment Restores Water Quality
\A/ t h H I H Historical leaking storage tanks and the demolition of a seal ren-
VV3I6rDOay irnprOVGQ derjng p|ant resulted in water quality impairments in the St. Paul
Salt Channel. As a result, the channel was placed on Alaska's 2002 303(d) list of impaired waters for
petroleum hydrocarbons, oil and grease. Efforts to restore water quality in the channel involved two
remediation actions—excavating and treating 9,234 cubic yards of soil by the National Oceanic and
Atmospheric Association (NOAA), and installing sandbags, filled with activated carbon, around the
periphery of the channel in two parallel trenches to filter the remaining groundwater flowing into the
channel. In response to NOAAs remediation action plan, Alaska's Department of Environmental Quality
(ADEC) moved this waterbody to a Category 4b ("impaired water with other pollution controls") in its
2002 Integrated Report. Sampling in August 2007 showed no contamination and that the channel met
Alaska's water quality standards (WQS) for petroleum hydrocarbons, oil and grease. Consequently, this
pollutant was removed from the list of impairments in 2008.
Problem
St. Paul Island lies in the Bering Sea, approximately
800 miles southwest of Anchorage, Alaska. The St.
Paul Salt Channel (also known as the Salt Lagoon
Channel) is tidally connected to the Salt Lagoon, St.
Paul Harbor and the Bering Sea. A contaminated
site (called the Salt Lagoon Diesel Seep) along the
east bank of the St. Paul Salt Channel contributed
petroleum products to the water.
The Salt Lagoon Diesel Seep area was formerly
the location of a seal by-products processing plant
that dated to 1918. The plant rendered fur seal
carcasses to oil and animal feed or meal. In 1977
the Tanadgusix (TDX) Corporation took control of
the plant. In 1984 the United State's decision not to
extend the Interim North Pacific Seal Convention
ended commercial seal harvests. Consequently, TDX
ended operation of the by-products plant in 1984 and
demolished the building in 1988. During the demo-
lition, the plant's boiler system spilled and leaked die-
sel fuel at the site. This added contamination on top
of what had accumulated over the previous 70 years.
For example, in 1957 a cracked valve on a fuel line
released 10,000 gallons of diesel fuel—only 2,000
gallons of which was recovered. By the time the
site was abandoned in 1988, contamination spread
across an area approximately 120 feet by 120 feet,
and at a depth of 3 to 5 feet (surface to groundwater).
NOAA acknowledged that it was responsible for the
site. Therefore, ADEC's Division of Spill Prevention
and Response, Contamination Sites Program issued
a notice of Violation/Request for corrective action by
NOAA. In 1999 NOAA discovered that the contamina-
tion was more widespread than previously thought.
Persistent oil sheens on the channel prompted tests,
which found that total aqueous hydrocarbons (TAqH)
exceeded the state numeric WQS of 15 micrograms
per liter (jug/L). Additionally, the channel failed to
meet Alaska's narrative WQS for petroleum hydro-
carbons, oil and grease, which states, "there may
be no concentrations of petroleum hydrocarbons,
animal fats, or vegetable oils in shoreline or bottom
sediments that cause deleterious effects to aquatic
life, and surface waters and adjoining shorelines
must be virtually free from floating oil, film, sheen,
or discoloration." As a result, ADEC listed 0.23 acres
of St. Paul Salt Channel on the 2002 303(d) list of
impaired waters for not supporting its designated
uses of growth and propagation of fish, shellfish,
other aquatic life and wildlife.
Project Highlights
In 2004 NOAA excavated 9,234 cubic yards of
petroleum-contaminated soil down to the water
table and thermally treated it off-site to volatilize,
desorb and combust the petroleum contaminants.
NOAA restored the bank of the channel with rock,
sand, and filter fabric and restored vegetation on
the top of the shoreline. The second major remedia-
tion effort involved installing two parallel rows of
granulated activated carbon on the downward slope
of the former by-products plant site. The activated
carbon in the sandbags filters any remaining pollut-
ants from the groundwater before they can enter
the channel (Figures 1 and 2). NOAA continues to
monitor the St. Paul Salt Channel for visual and
chemical signs of contamination.
-------
Results
NOAA's efforts to restore St. Paul Salt Channel
were successful. Water quality monitoring showed
that the channel met Alaska's WQS for petroleum
hydrocarbons, oil and grease. On February 13,
2006, ADEC concurred with NOAA that no further
actions are needed for the Salt Lagoon Diesel
Seep site. Continued semiannual monitoring, as
well as visual inspections for sheens on the chan-
nel, confirmed that concentrations of petroleum
hydrocarbons remain below 15/jg/L and that no
animal fats or vegetable oils remain in shoreline or
bottom sediments that cause deleterious effects
on aquatic life. Therefore ADEC removed petro-
leum hydrocarbons, oil and grease from the list of
impairments in 2008.
Partners and Funding
In October 2007, NOAA completed the successful
cleanup of all 58 sites on St. Paul Island to protect
human health, welfare, safety and the environment.
ADEC oversaw the cleanup to ensure that it adhered
to Alaska state standards. Local communities, in
cooperation with NOAA and ADEC, also helped the
restoration process by raising awareness of the
problem and offering assistance in solutions. Since
1996, $64 million in federal monies were approved
as a special appropriation for the Pribilof Islands, of
which St. Paul Island is a part.
Figure 1. The Salt Lagoon Diesel Seep area after
NOAA removed contaminated soil and restored the
St. Paul Salt Channel shoreline.
9.0
8.0
7.0
6.0
5.0
4.0
MHW 3.0
MIL 2.0
1.0
MLLW 0
-1.0
-2.0
-3.0
-4.0
• Approximate vegetation limit
Zone of Excavation of Petroleum
Contaminated Soil and Sediment*
10
-20 -15 -10 -505
Typical Shoreline Cross Section Prior to Restoration
MHW = Mean High Water MTL= Mean Tide Level MLLW= Mean Level LowWater
15
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1-0
0
-1.0
-2.0
-3.0
-4.0
Restored bank elevation varies from
approx. 5.5 to 7.5 feet ablve MLLW'
2.5'thick layer cf"B" rock
Vthick layer of sand fill
Erosion Control Matting
Topsoil & vegetation wrapped
in erosion control matting /
Scoria backfill
-20 -15 -10 -5
Shoreline Restoration After Excavation
Sandbags filled with Granular
Activated Carbon (GAC Barrier)
-Feet
20
10
15
Figure 2. Cross-section of the shoreline in the contaminated area before (left) and after (right) restoration efforts. The
contaminated soil was removed and replaced with rock, sand and a granular activated carbon barrier.
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-08-001L
September 2008
For additional information contact:
Louis Howard
Alaska Department of Environmental Conservation
907-269-7552
louis.howard@alaska.gov
------- |