specific to an area of ERF or to the application of a
Pumps are also installed to drain areas of
specific remedial alternative. It must be achieved
pond groups that do not drain via the man-
on the basis of information about ERF as a whole
made ditch. The pond draining allows the
sediment to dry so that the existing WP can
because the ducks have been observed to fly all
sublimeoxidize. After a few years of pond
over the flats, and WP has been detected in many
draining, AquaBlokTM is then spread over
areas. The following monitoring will be per-
any remaining contaminated areas. Detailed
formed annually to improve understanding of
monitoring is included in this alternative.
the baseline condition and to determine progress
Hazing is also performed as a temporary
toward achieving RAO number 1 for alternatives
interim measure.
2 through 5:
Alternative 5, AquaBlokTM. The product is
Telemetry. As discussed in the RI report,
applied over the surface area of the pond
birds are captured, small radio transmitters
groups. Detailed monitoring is included in
are attached to them, and then they are
this alternative. Hazing is also performed as
released in the area in which they were cap-
a temporary interim measure.
tured. In this study approximately 100 to
A review will be conducted after 5 years of
150 mallards will be tracked during the 2-
remedy implementation and monitoring to deter-
month fall migration period.
mine whether RAOs are being met.
Aerial bird population surveys. Annual popu-
lation surveys will provide knowledge of
Environmental impacts
trends in the use of ERF, which can help in
ERF supports a diverse community of water-
understanding specific or unusual results
fowl and shorebirds. Observations have shown
form the telemetry studies.
that the ducks prefer specific types of habitat:
Aerial photography. Aerial photography pro-
sedge marsh, permanent ponds, and intermittent
vides confirmation information about bird
ponds. This preference for habitat types has been
populations at specific ponds when it is
considered in this FS.
coordinated with the aerial bird surveys.
Remedial alternatives 3 and 4 involve draining
The evaluation of RAO number 2, reduction of
the selected pond or pond group. These treat-
hot zones, is maintained by updating a yearly
ments are expected to modify ERF habitat to
inventory of treated hot ponds that have success-
varying degrees. Pond draining by pumping
fully reduced WP exposure pathways in imple-
(alternative 3) is expected to lead to only tempo-
menting alternatives 2 through 5. Monitoring for
rary changes in the habitat, whereas pond drain-
reduction in WP exposure pathways (the third
age by breaching (alternative 4) is expected to
RAO) will be achieved by sampling for WP and
result in a more permanent change in habitat. High
conditions that foster containment or sublima-
residual risk is expected to remain as a result of
tionoxidation of WP in sediments.
AquaBlokTM application under alternative 5.
A breached pond will fill and drain with lower
Detailed analysis
high tides than a pond drained by pumping.
The NCP requires that each alternative be anal-
Changes in plant species composition would be
yzed on the basis of nine decision making criteria:
most dramatic under alternative 4 and will mod-
Overall protection of human health and the
ify the habitat quality for selected bird species. In
environment.
addition, it is unlikely that breached ponds can be
Compliance with applicable or relevant and
restored. The erosion patterns that would be cre-
appropriate requirements (ARARs).
ated over time reduce the feasibility of reversing
Long-term effectiveness and permanence.
the process and restoring the ponds (as perma-
Reduction of toxicity, mobility, or volume
nent or intermittent ponds) once remediation of
through the use of treatment.
the ponds is completed.
Short-term effectiveness.
Implementability.
Monitoring strategy
Cost.
Because of the nature of the RAOs, the contam-
State acceptance.
ination at ERF, and the remedial alternatives,
Community acceptance.
detailed monitoring will be necessary to deter-
The first seven criteria are used in the detailed
mine if and when the RAOs will be met. The first
analysis of the remedial alternative in this FS. The
RAO, reducing dabbling duck mortality, is not
last two will be evaluated following receipt of
13
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