through explosive ditching and pumping, seem to
tion and concentration of WP in sediment and wa-
ter samples in detail and conducted a literature re-
be effective in reducing WP concentration. Espe-
view of the chemical and physical properties of
cially promising is the pond pumping remedia-
WP.
tion method, which removes overlying water
Biological and toxicological studies, which were
from contaminated sediments. First tried on a limit-
mostly conducted by the U.S. Fish and Wildlife Ser-
ed scale in 1997 as part of the feasibility study,
vice (USFWS) and Dartmouth Medical School
pumping reduced contamination in a large, highly
(DMS), primarily focused on characterizing WP tox-
contaminated pond by over 80% during one sum-
icity in mallards. Researchers from USFWS and DMS
mer. Dredging was dropped from consideration
conducted experiments to determine the lethal
following this test, and six pumps were deployed
dose of WP to mallards, the distribution of WP in
in 1998 with similar results.
tissues of ducks poisoned with WP, the risk of sec-
ondary poisoning to predators of ducks, the identi-
Regulatory actions
fication of biomarkers in birds poisoned with WP,
In June 1994, ERF was placed on the National
reproductive toxicity, the feasibility of treating WP-
poisoned birds, preliminary theories on the mech-
Protection Agency (USEPA). Designated as Oper-
anism of toxicity, and WP concentrations in tissues
able Unit C (OUC), ERF became a Federal Super-
of bird, invertebrate, and fish samples collected at
fund site, which mandates that the area be subject
ERF. Plant samples were also collected and analyzed
to the remedial response requirements of the Com-
for WP by CRREL. Waterfowl surveys, which includ-
prehensive Environmental Response, Compensation,
ed utilization of ERF, mortality rate, and distribution
and Liability Act (CERCLA), as amended by the Su-
and movements, were conducted by USFWS, the
perfund Amendments and Reauthorization Act of
New England Institute of Landscape Ecology
1986. Prior to the actual placement of ERF on the
(NEILE), and the U.S. Department of Agriculture
NPL, the U.S. Army Engineer District, Alaska,
(USDA), respectively.
hired a private consulting firm, CH2M Hill, to
review all previous studies and to aid in organizing
an effective and coordinated CERCLA remedial
Remedial investigations and feasibility studies
Several remedial methods were also evaluated
activity. In 1994, CH2M Hill, working in conjunc-
from 199194. Waterfowl deterrent methods--
tion with the agencies involved in the ERF inves-
such as hazing, exposure to methyl athranilate,
tigation, produced the Comprehensive Evaluation
and covering of contaminated areas with Concov-
Report (CER), which reviewed all work that had
er, AquaBlokTM, and BentoBalls--were inves-
been done through 1994. Quality assurance (QA)
tigated by the USDA. CRREL also studied using
plans (1994), as well as field working plans (1995),
various geosynthetic coverings for the contaminat-
following the CERCLA guidelines were also writ-
ed areas, as well as looked at methods to dry sedi-
ten. In 1997, the final draft of Operable Unit C, Final
ments in situ and drain ponds. Finally, CRREL de-
Feasibility Study Report and Operable Unit C, Remedial
veloped a database for ERF, using a Geological In-
Investigation Report became available. The final risk
formation System (GIS), to maintain and update
assessment report became incorporated in the Oper-
incoming data.
able Unit C, Remedial Investigation Report. The
CERCLA documents, Proposed plan for cleanup action
Studies conducted during 199598 mostly
at Operable Unit C and the Record of Decision for Oper-
focused on active remediation and monitoring its
able Unit C, are now also available to the public.
effects. In 1995, treatability studies, such as pond
With the signing of the Record of Decision (ROD)
draining by explosive ditching, dredging, and the
in October 1998, full-scale remediation of Eagle
enhancement of natural attenuation processes,
River Flats will begin. The preferred remediation
were conducted to determine how effective these
treatments are in reducing WP availability. Hazing
method is pond pumping, with the application of
and AquaBlokTM coverage were also evaluated for
AquaBlokTM in areas that pumping cannot address.
their effectiveness in breaking the contaminant
Effectiveness will be measured in two ways. Base-
pathway. Waterfowl surveys were continued to
line sampling for the contaminant will be carried
monitor the mortality, movement, and distribution
out in untreated ponds and ponds in the process of
of migrating birds.
being treated in the spring. In the fall, the treated
In 1996 and 1997, studies were again geared tow-
ponds will once again be sampled to determine the
ards treatment of contaminated areas to reduce WP
reduction in white phosphorus contamination.
availability. Dredging and draining of ponds, both
Waterfowl mortality will be monitored using radio-
3
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