1.1 MB pdf - Bolsa Chica Lowlands Restoration Project

SECTION 3: ANALYSIS
These nine primary principal components were back-correlated with the original variables
in the dataset (Table 3-24). The first principal component is highly correlated with
petroluem compounds (e.g., PAHs, TPH, waste oil, etc.) and may be interpreted as a
measure of petroleum contamination. The second principal component best correlates to
metals (nickel, vanadium, mercury, zinc, and lead) and total PCBs. The third component is
positively correlated to organochlorines and copper and negatively correlated to petroleum
compounds. Component 4 is negatively correlated to PAHs and positively correlated to
organochlorines and metals (Table 3-24). Component 5 is positively correlated to inorganics
and negatively correlated to organochlorines.
3.2.2 Stressor-Response Profile
The stressor-response profile presents the results of the stressor-response analysis. It results in
a set of reference toxicity values (RTVs) that were then used as the basis for estimating risks to
representative species at the Bolsa Chica Lowlands. The RTVs were selected primarily from
the site-specific dose-response information, in addition to other available sources, including
toxicological databases, wildlife toxicological reviews, and scientific literature.
The most conservative of the reliable RTVs generally were used, because of the stated future
land use (mitigation and wildlife refuge). The RTVs were selected according to a specified
hierarchy. This was presented for aquatic organisms (sediment and surface water exposure)
in Sections 2.3.3 and 3.2.2, and for terrestrial organisms in Section 3.2.2. The RTVs included
both acute and chronic effect levels. The selection of RTVs for the various receptor groups is
presented below. In addition, the GIS application and Tables 3-25 to 3-28 identify the RTVs
that were used in the risk calculations. RTVs representing no observed adverse effect levels
(NOAELs), NOECs, lowest observed adverse effect levels (LOAELs), or LOECs are
preferred over those for lethal doses or concentrations (such as LD 50 or LC 50 ).
The RTVs for terrestrial plants and invertebrates exposed to sediment/soil were obtained
from several sources, including wildlife toxicity reviews, literature searches, and toxicity
databases, such as PHYTOTOX and the database compiled by Efroymson et al. (1997a and
1997b). The RTVs are presented in Table 3-25 for terrestrial plants and in Table 3-26 for
terrestrial invertebrates.
The RTVs for birds and mammals exposed to sediment/soil and surface water were
obtained from several sources, including wildlife toxicity reviews, literature searches,
Health Effects Assessment Summary Tables (HEAST), Integrated Risk Information System
(IRIS), and toxicity databases, such as TERRETOX. The most conservative RTVs were
typically selected for terrestrial receptors with the following two additional criteria: Where
possible, a) values that were based on test species most similar to representative Bolsa Chica
species were selected, and b) sources reporting both a NOAEL and a LOAEL were generally
preferred. The RTVs are presented in Table 3-27 for birds and in Table 3-28 for mammals.
The RTVs for aquatic organisms (e.g., benthic macroinvertebrates) exposed to sediment
were obtained from the dose-response regression analyses conducted on the amphipod
survival and reburial bioassays and Nereis bioaccumulation studies described in the
previous section. The ER-L and ER-M values from Long et al. (1995), and Long and Morgan
(1990) where not available in Long et al. (1995), are also included as reference benchmarks.
RTVs obtained from Long and Morgan (1990) include 4,4’-DDD, 4,4’-DDT, chlordane, and
SAC/143368(003.DOC) 3-37 ERA REPORT
7/31/02