1.1 MB pdf - Bolsa Chica Lowlands Restoration Project

SECTION 3: ANALYSIS
preliminary screening. As expected, the corresponding number of Cells where the
secondary screening levels (ER-Ms or LC 50 s) were exceeded was much smaller than for the
preliminary screening level. Chemical group-specific discussions are presented below:
Metals
Exceedances of the preliminary screening levels (LC 20 , ER-L, or background levels) were
observed in most Cells within the Bolsa Chica Lowlands. Exceedances of the preliminary
screening levels were not observed in the seven Cells listed above or in Cell 6, Cell 37,
Cell 49, Cell 58, or Cell 60 (Figure 3-7).
One or more exceedances of the ER-M for individual metals were observed in only 4 Cells:
Cell 1A, Cell 3, Cell 34, and Cell 35 (Figure 3-8).
Petroleum Hydrocarbons
Exceedances of the preliminary screening levels (LC 20 or ER-L) were observed in most Cells
within the Bolsa Chica Lowlands. Exceedances of the preliminary screening levels were not
observed in the seven Cells listed above or in Cell 9, Cell 10, Cell 13, Cell 19, Cell 25, Cell 31,
Cells 38 through 45, Cell 50, Cell 51, Cell 61, Cell 62, or Cell 67 (Figure 3-9).
One or more exceedances of the secondary screening levels (LC 50 ) for petroleum
hydrocarbons were observed in only 6 Cells: Cell 1A, Cell 3, Cell 4, Cell 21, Cell 34, and
Cell 36 (Figure 3-10).
Chlorinated Pesticides
Exceedances of the preliminary screening levels (LC 20 or ER-L) were observed in most Cells
within the Bolsa Chica Lowlands. Exceedances of the preliminary screening levels were not
observed in the seven Cells listed above or in Cell 4, Cell 6, Cell 14, Cell 21, Cell 25, Cell 31,
Cell 37, Cell 39, Cell 47, Cell 62, or Cell 67 (Figure 3-11).
One or more exceedances of the secondary screening levels (ER-M) for chlorinated
pesticides were observed in 11 Cells: Cell 1, Cell 15, Cell 26, Cell 30, Cell 32, Cell 35, Cell 42,
Cell 46, Cell 52, Cell 53, and Cell 58 (Figure 3-12).
PCBs
Exceedances of the preliminary screening levels (LC 20 or ER-L) were observed in fewer Cells
within the Bolsa Chica Lowlands than for other chemical groups. Exceedances of the
preliminary screening levels were observed in 6 Cells: Cell 1A, Cell 26, Cell 34, Cell 36, Cell
47, and Cell 52, as well as Inner Bolsa Bay (Figure 3-13).
One or more exceedances of the secondary screening levels (ER-M) for PCBs were observed
in only 2 Cells, Cell 26 and Cell 47 (Figure 3-14).
Phthalates
Exceedances of the preliminary screening levels (LC 20 ) were observed in fewer Cells within
the Bolsa Chica Lowlands than for other chemical groups except PCBs. Exceedances of the
preliminary screening levels were observed in 15 Cells: Cell 1A, Cell 3, Cell 7, Cell 9, Cell 12,
Cell 21, Cell 26, Cell 32, Cell 34, Cell 36, Cell 42, Cell 45, Cell 48, Cell 49, and Cell 63, as well
as Inner and Outer Bolsa Bay (Figure 3-15).
One or more exceedances of the secondary screening levels (LC 50 ) for phthalates were
observed in only 3 Cells: Cell 7, Cell 21 and Cell 36 (Figure 3-16).
SAC/143368(003.DOC) 3-19 ERA REPORT
7/31/02