1.1 MB pdf - Bolsa Chica Lowlands Restoration Project
1.1 MB pdf - Bolsa Chica Lowlands Restoration Project
1.1 MB pdf - Bolsa Chica Lowlands Restoration Project
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SECTION 4: RISK CHARACTERIZATION<br />
Upland Bird<br />
Evaluations for upland bird receptors (Table 4-2) indicated that there was some possible risk<br />
(Category C) to arsenic, cobalt, lead, and zinc; and uncertain risk (Category U) for<br />
chromium and selenium. Sparrows were more sensitive and had NOAEL HQs ranging from<br />
1.4 (arsenic) to 7.2 (chromium).<br />
Mammals<br />
Evaluations for mammals in the Gas Plant Pond Area (Table 4-2) indicated that arsenic<br />
poses a possible (Category B) risk, and barium, lead, and zinc pose some possible risk<br />
(Category C). Chemicals that exceeded NOAELs, but did not have LOAELs (Category U<br />
risk) included cobalt, selenium, and vanadium. NOAEL HQs were typically higher for the<br />
mouse and ranged from 2.7 (cobalt) to 37 (barium). NOAEL HQs for coyotes ranged from<br />
1.3 (zinc) to 3.5 (barium). In addition to the inorganic COECs, dieldrin also showed some<br />
possible risk to coyotes (HQ=1.9).<br />
4.<strong>1.1</strong>.3 Muted Tidal Plus Rabbit Island<br />
Terrestrial Plants<br />
Evaluations for terrestrial plants (Table 4-1) indicated that both nickel and selenium<br />
exceeded chronic NOECs with HQs of 5 and 8.4, respectively. Chemicals exceeding chronic<br />
LOECs included 14 inorganics and 3 organics with HQs ranging from 1 for cadmium to<br />
480 for lead. These chemicals are considered to pose a possible risk to terrestrial plants<br />
(Category B). Of those chemicals exceeding chronic LOECs, 4 were evaluated using an<br />
exposure point concentration that was ½ the reporting limit for a non-detect.<br />
Terrestrial Invertebrates<br />
Estimates of potential risks to terrestrial invertebrates (Table 4-1) indicated that risk for zinc<br />
was uncertain because it exceeded a chronic NOEC (HQ=1.4), but a LOEC was not available.<br />
Eight other inorganics and 1 organic posed a possible risk based on exceedance of a chronic<br />
LOEC. HQs for these chemicals ranged from 1.3 to 34, with barium (HQ=34) and lead<br />
(HQ=19) showing the greatest potential for risk.<br />
Upland Birds<br />
Evaluations for upland birds showed that lead posed possible risk (Category B) to the<br />
sparrow with a NOAEL HQ of 14 and a LOAEL HQ of 1.4 (Table 4-2). Cobalt and zinc<br />
posed some possible risk to upland birds, and chromium posed an uncertain risk to<br />
sparrows. NOAEL HQs ranged from 1.3 for zinc (kestrel) to 14 for lead (sparrow).<br />
Mammals<br />
Risk estimates for the harvest mouse and the coyote (Table 4-2) indicated that barium and<br />
lead posed some possible risk (Category C) to the mouse with HQs of 20 and 5, respectively.<br />
Barium was the only COEC identified for coyotes. Chemicals with uncertain risk (Category<br />
U) included cobalt and vanadium.<br />
4.<strong>1.1</strong>.4 Seasonal Ponds<br />
Terrestrial Plants<br />
Evaluations for terrestrial plants (Table 4-1) showed that nickel and selenium exceeded chronic<br />
NOECs with HQs of 10 and 11, respectively. Chemicals that exceeded chronic LOECs (possible<br />
risk – Category B) included 12 inorganics and 2 organics. HQs ranged from 2.1 for molybdenum<br />
SAC/143368(004.DOC) 4-5 ERA REPORT<br />
7/31/02
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