site model, preliminary human health and envi-
lower precision, accuracy, and completeness than
ronmental risk assessments, and discussion of
data collected to determine toxicity and cleanup
levels. Examples of screening-level data include
potential remedial technologies; and described
the following:
the data needed for key decisions of the CERCLA
Presence or absence of WP.
process. It was used to guide planning for the
Nonparametric observations such as forag-
1994 field season.
ing behavior.
In 1995, the data review consisted of the fol-
Field measurements (for example, pH, salin-
lowing steps:
ity, temperature).
Review existing data. The data review
included the data summarized in the CER
and the data presented in the preliminary
CH2M Hill (1995) Eagle River Flats. Final 1995
reports prepared by researchers involved in
Work Plan. Contract Report to U.S. Army Corps of
the 1994 field and laboratory work.
Engineers, Alaska District, and U.S. Army, Alaska.
Determine site decisions. The evaluation
June.
focused on the supporting data necessary to
Project objectives
determine which areas require remediation
During the past 10 years, considerable data
and which remediation methods are appro-
have been collected at the ERF. In the early years,
priate for consideration.
the objective was to collect data that could help
Develop evaluation matrices. Three matri-
identify the cause or causes of the acute waterfowl
ces and criteria were developed to assess
mortality observed at the ERF. With the identifica-
data gaps. Further details are provided be-
tion of WP as the causative agent, the focus of the
low.
studies shifted to understanding how WP moves
Evaluate data needs and availability. The
and is lost in the wetland environment, as well as
existing information was evaluated in the
studying the toxicology to discover the mecha-
context of the matrices, and criteria were de-
veloped in the previous step. Further details
nism of action and the doseresponse relation-
are discussed below.
ship. A few studies began to investigate potential
The results of the risk assessment, which are
remedial measures.
supported by the conceptual site model (CSM),
With the inclusion of Fort Richardson on the
have the greatest influence on determination of
as a contaminated site under the Federal Compre-
areas requiring remediation. The information cat-
hensive Environmental Response, Compensation, and
egories for these assessments are the nature and
extent of contamination (contaminant character-
has shifted to site remediation and compilation of
ization), the fate and transport processes that
the data needed to support site remedial deci-
sions. Two key decisions for site remediation are
exposure and effects of receptors. These categor-
the identification of areas that need remediation
ies were further divided for the analysis of data
and the choice of remedial actions to achieve the
gaps. The availability of information was consid-
remedial action goals.
ered for several different geographical areas of
the ERF, particularly areas that have been assess-
The following are study objectives in 1995:
ed in the past. The results are summarized.
Identify data gaps that need to be filled to
In general, the critical data gaps are those cells in
support the key CERCLA decisions.
the matrix where the impact is High, and the confi-
Execute the field and pilot studies that will
dence is Low. Other critical data gaps are those cate-
fill those gaps.
gories that have not yet been characterized in areas
where high usage have been observed. In summa-
Scope of work
The process by which the data gaps were iden-
ry, this analysis shows that additional information
tified is described below. An overview of each
is needed on the following:
study planned for 1995 is provided. These studies
Horizontal extent of WP on Racine Island.
are intended to fill the data gaps identified. Specif-
This data gap will not be addressed in 1995.
ic 1995 project scopes of work can be found.
Vertical extent of WP in areas with high
In 1994, the Eagle River Flats Comprehensive
waterfowl use. This data gap will not be
Evaluation Report (CER) summarized the studies
addressed in 1995; however, a treatability
performed before 1994; presented a conceptual
study will be conducted to evaluate a
9
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