1.1 MB pdf - Bolsa Chica Lowlands Restoration Project

CHAPTER 5: SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS
concentrations to those below acute or chronic effects levels. This reduction in risk will
contribute to achievement of the management goals for the site, which are stated as follows:
• Sediment, surface water quality, and food source conditions capable of supporting
terrestrial, aquatic, and semi-aquatic plant and wildlife populations that would typically
be found in Full Tidal and Managed Tidal coastal wetland habitats, and non-tidal
Seasonal Ponds.
• Sediment, surface water quality, and food source conditions supportive of individuals of
special-status biota and migratory birds protected under the Migratory Bird Treaty Act
likely to be found in Full Tidal and Managed Tidal coastal wetland habitats, and nontidal
Seasonal Ponds.
5.3 Recommendations
Chemicals that were not identified as COECs fall into two categories: (a) those that have low
or no potential for exposure or risk and (b) those that have no known reference toxicity
values for the receptors we evaluated. The development of clean-up strategies for these
chemicals is not recommended.
Chemicals identified as COECs in the Bolsa Chica Lowlands are recommended for further
evaluation or remediation. Clean-up goals should be developed based on the receptors that
may be at risk.
The integrated nature of the exposure (through surface water, sediment/soil and food web
pathways) demonstrates a need to remove the contamination at the source. In most
instances, clean-up of COECs in the sediment/soil would provide the greatest opportunity
to reduce the risk through improving the habitat and reducing the exposure potential to
lower trophic organisms and thus reducing the contamination throughout the food chain.
The following factors should be considered in the development of clean-up goals:
• Magnitude of observed concentrations and toxic concentrations as defined by the
reference toxicity values in this ERA
• Likelihood of persistence of contamination without remediation
• Functional value and uniqueness of the Bolsa Chica site in relation to the surrounding
area
• Recovery potential of the site
• Short-term and long-term impacts of clean-up on the site habitat and larger ecosystem
• Effectiveness of a clean-up effort; that is, whether there are other continuing, nearby
contaminant releases that will continue to adversely affect the ecosystem after cleanup is
implemented
The results of the ERA provide adequate information to evaluate the need for clean-up and
appropriate levels of clean-up. However, additional delineation of individual sites is needed
to determine the bounds of the clean-up effort.
SAC/143368(005.DOC) 5-7 ERA REPORT
7/31/02