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 />
Potential risks to upland birds and mammals were in the some possible range (Category C)<br />
for metals. Arsenic in mice was the only chemical with a probable risk (Category B –<br />
exceedance of a LOAEL).<br />
4.2.5.2 Sediment/Soil – Aquatic Receptors<br />
Potential risks to aquatic plants are the same as those reported for terrestrial plants in the<br />
previous subsection because both receptors were evaluated using the same RTVs.<br />
For sediment-related risks to aquatic invertebrates, probable risks were estimated for metals<br />
(arsenic, chromium, selenium, thallium), pesticides (4,4’-DDD, total DDT), petroleumrelated<br />
chemicals (acenaphthene, fluorene, napthalene, oil and grease, phenanthrene,<br />
TPH-diesel, waste oil, low MW PAHs, total PAHs), total PCB, and di-n-octylphthalate.<br />
Possible risks (Category B) were estimated for several other metals, pesticides, and PAHs.<br />
Estimated risks to semi-aquatic birds were in the possible range for several metals (cobalt,<br />
copper, lead, zinc), as well as 4,4’-DDE and Aroclor 1254.<br />
4.2.5.3 Surface Water<br />
Potential risks to aquatic organisms exposed to surface water were limited to diesel and<br />
waste oil. Both had possible risks.<br />
4.2.6 Muted Tidal Plus Rabbit Island<br />
Potential risks were evaluated for terrestrial, aquatic, and semi-aquatic receptors in the<br />
Muted Tidal and Rabbit Island area. All chemicals with HQs exceeding one were retained as<br />
COECs (Tables 4-5, 4-6, and 4-7). A summary of the potential for risk is presented below for<br />
each exposure medium.<br />
4.2.6.1 Sediment/Soil – Terrestrial Receptors<br />
Estimated risks to terrestrial plants were in the possible range (Category B) for metals and<br />
PAHs. Chemicals with the highest estimated risk consisted of arsenic, barium, copper, lead,<br />
benzo(a)pyrene, and benzo(g,h,i)perylene.<br />
Chemicals that showed potential risks to terrestrial invertebrates were limited to metals,<br />
most with lower HQs. The highest HQs were observed for barium and lead. Potential risks<br />
to upland birds and mammals showed possible risks from lead. Some possible risks were<br />
estimated for other metals. The highest HQs were observed for barium and lead.<br />
4.2.6.2 Sediment/Soil – Aquatic Receptors<br />
Potential risks to aquatic plants were the same as those listed above for terrestrial plants<br />
because they were evaluated using the same RTVs.<br />
For sediment-related risks to aquatic invertebrates, probable risks (Category A) were<br />
estimated for metals (chromim, cobalt, copper, lead, nickel, selenium, thallium, and zinc),<br />
pesticides (4,4’-DDD, 4,4’-DDE, 4,4’-DDT , chlordane [alpha, gamma, technical], dieldrin,<br />
endrin, endrin aldehyde, endrin ketone, total DDT ), petroleum (acenaphthylene, fluorene ,<br />
oil and grease, phenanthrene, TPH diesel, waste oil, low MW PAHs), and other organics<br />
(di-n-ocylphthalate, total PCB). Possible risks (Category B) were estimated for several other<br />
metals and PAHs. Potential risks to semi-aquatic birds were in the possible range for several<br />
ERA REPORT 4-22 SAC/143368(004.DOC)<br />
7/31/02
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