1.1 MB pdf - Bolsa Chica Lowlands Restoration Project

SECTION 1: INTRODUCTION
The ERA and CSP are being conducted for the Bolsa Chica Lowlands, as described in the
original and revised Work Plans for the project (CH2M HILL, 1998a and 2000). This ERA is
the fourth in a series of reports and data deliverables. Previous reports included the Scoping
Assessment (CH2M HILL, 1998b), the sediment sampling analyses results for proposed
dredge areas that were based on a separate sampling plan (Kinnetic Laboratories/ToxScan,
Inc. and CH2M HILL, 1999), and the Ecological Effects Characterization (EEC)
(CH2M HILL, 1999), which presented the first two major components of the ERA-the
Problem Formulation and the Analysis.
1.1 Objectives and Scope
The overall objective of the ERA is to define the nature of site contamination in order to
develop site-specific, clean-up criteria and goals to protect fish and wildlife and their food
chains in the Bolsa Chica Lowlands. The overall objective of the CSP will be to define the
extent of site contamination. Two of the main tasks to accomplish this objective were to
conduct field sampling for contamination and test for toxicity or bioaccumulation of
contaminants in the Lowlands. The resulting information, which supplemented existing
data from the Lowlands, was used to:
• Aid in the Preliminary Level II Preacquisition Environmental Contamination Survey for
portions of the Bolsa Chica Lowlands where existing data are insufficient, especially for
the Fieldstone Property and Lowland Pocket areas.
• Support the ERA by providing data over wider areas of the Lowlands than has been
available and by providing the chemical and bioassay/ bioaccumulation data necessary
to assess ecological risks and determine clean-up criteria.
• Provide additional data at known or suspected contaminated sites within the Bolsa
Chica Lowlands, to determine the nature and extent of this contamination.
• Obtain supplemental physical and environmental contaminant data to aid in the design
of wetland restoration, including dredging permitting and disposal/reuse options.
The EEC Report (CH2M HILL, 1999) provided information related to these first three
purposes. The specific objectives of that report were to:
• Incorporate and update the information from the Scoping Assessment to provide the
Problem Formulation for that report and the future ERA.
• Present results of the ERA Sampling and Analyses (as described in the Work Plan and
summarized subsequently) to provide the Exposure Characterization and the Ecological
Effects Characterization for information collected onsite.
This ERA completes the process begun in the EEC Report (CH2M HILL, 1999) and, in
combination with the dredge area characterization report (Kinnetic Laboratories/ToxScan,
Inc., and CH2M HILL, 1999), fulfills all four purposes listed previously. The specific
objectives of this ERA report are to:
• Incorporate environmental data from the ERA Sampling and Analyses, the Focused
Sampling and Analyses, and relevant data from the Tetra Tech Phase II Environmental
SAC/143368(001.DOC) 1-3 ERA REPORT
7/31/02