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 />
bioassays were not toxic to test organisms at the highest concentration tested, so NOECs<br />
were 100 percent of the sample and the LOECs were greater than 100 percent.<br />
Fish<br />
Copper (total and dissolved) was the only chemical with probable risk to fish (Table 4-4).<br />
Arsenic, lead, nickel, 4,4’-DDT, and dieldrin showed possible risk (Category B). The chronic<br />
CA-WQS HQs for these chemicals were all less than 10 with the exception of 4,4’-DDT (13).<br />
There were also several chemicals with some possible risk (Category C). The NOEC HQs<br />
for these ranged from 1.0 (dissolved lead) to 6.3 (zinc). Chemicals with uncertain risks<br />
(Category U) had fish NOECs less than 10 except for TPH-diesel (1,491) and waste oil (754).<br />
Toxicity bioassays were conducted on surface waters collected from Cell 63 (topsmelt). The<br />
bioassays using topsmelt resulted in no adverse effects on test organisms using 100 percent<br />
sample. The NOEC was then 100 percent of sample and the LOEC was greater than<br />
100 percent.<br />
4.1.3.4 Garden Grove-Wintersburg Flood Control Channel<br />
Aquatic Plants<br />
Estimation of potential risks to aquatic plants showed that copper was the only chemical<br />
that had a probable risk (Category A) with an acute CA-WQS HQ of 3.5 (Table 4-4). Possible<br />
risk (Category B) was indicated for dissolved copper, nickel, zinc, and dieldrin. Dissolved<br />
copper exceeded both the lowest chronic value for plants and the CA-WQS chronic value<br />
with HQs of 4.7 and 1.5, respectively. Nickel (6.6) and dieldrin (52) also exceeded the CA-<br />
WQS chronic level, but not the plant lowest chronic value. Zinc exceeded the plant lowest<br />
chronic value, but not the CA-WQS chronic value.<br />
Aquatic Invertebrates<br />
Copper was the only chemical with probable risk to aquatic invertebrates (Table 4-4). There<br />
were several chemicals with possible risk (Category B). The LOEC HQs for these chemicals<br />
were less than 10 with the exception of 4-nitrophenol (23) and dieldrin (52). Arsenic (total<br />
and dissolved), chromium, dissolved cobalt, and zinc all had some possible risk<br />
(Category C). The NOEC HQs for these chemicals range from 1.4 (dissolved arsenic) to<br />
45 (4-nitrophenol).<br />
Toxicity bioassays were conducted with surface water collected from Cell 52. Given the total<br />
dissolved solids (electrical conductivity), Mysidopsis were used instead of Ceriodaphnia. As<br />
such, the test waters were adjusted for salinity. The results indicated that samples were not<br />
toxic to organisms at the highest concentration tested; therefore, the NOEC was 100 percent<br />
of the sample and the LOEC was greater than 100 percent of the sample.<br />
Fish<br />
Risk evaluations for fish indicated that copper was the only chemical with probable risk<br />
(Category A) to fish (Table 4-4). Chemicals with possible risk included dissolved copper,<br />
nickel, and dieldrin. The CA-WQS chronic HQs for these chemicals ranged from<br />
1.5 (dissolved copper) to 52 (dieldrin). Cadmium, lead, and zinc showed some possible<br />
risk (Category C) with fish NOEC HQs ranging from 2.9 to 6.7.<br />
SAC/143368(004.DOC) 4-17 ERA REPORT<br />
7/31/02
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