1.1 MB pdf - Bolsa Chica Lowlands Restoration Project

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SECTION 4: RISK CHARACTERIZATION Fish Estimates of potential risk to fish (Table 4-4) indicated that dissolved copper and zinc pose a probable risk (Category A) to fish. Both exceeded the CA-WQS acute value (for which, the HQs were close to 1), however, zinc did not exceed the fish NOEC derived from toxicity bioassays. This is most likely due to the fact that there was no toxicity observed in the bioassay and the zinc concentration was low. Toxicity bioassays used surface water collected from Cell 11. Bioassays were conducted using topsmelt. Samples were not toxic to topsmelt at the highest concentration tested. Accordingly, the NOEC was 100 percent of sample and the LOEC was greater than 100 percent. 4.2 Risk Description The Risk Description evaluates the different sources of information concerning potential risks including HQ risk estimates, results of toxicity bioassays, bioaccumulation testing, and any observed ecological effects at the Lowlands to establish a weight-of-evidence for determination of COECs. The weight-of-evidence for sediment/soil and surface water is presented by area in the following subsections. The selected COECs are summarized for each area in Table 4-5 (sediment/soil for terrestrial receptors), Table 4-6 (sediment/soil for aquatic receptors and semi-aquatic birds), and Table 4-7 (surface water for aquatic receptors). Any chemical with hazard quotient exceeding 1 was identified as a COEC. In addition, chemicals showing significant bioaccumulation in Nereis were also retained as COECs. 4.2.1 Bolsa Bay Potential risks were evaluated for aquatic and semi-aquatic receptors in Bolsa Bay. All chemicals with HQs exceeding one were retained as COECs (Tables 4-6 and 4-7). A summary of the potential for risk is presented below for each exposure medium. 4.2.1.1 Sediment/Soil Review of the HQs for aquatic plants indicated that metals and selected PAHs [benzo(a)pyrene and benzo(g,h,i)perylene] in sediments pose a possible risk (Category B) COECs with the highest risk potential include arsenic and lead. Evaluation of exposures to aquatic invertebrates exposed to Bolsa Bay sediment samples indicated that selenium, nickel, and thallium had the highest potential for risks among the inorganics (Category A). Among the organics, pesticides (4,4’-DDD, 4,4’-DDE, chlordane, and total DDT), TPH-diesel, and waste oil were associated with the highest potential risks (Category A). Evaluation of potential risks for semi-aquatic birds indicates that metals and pesticides pose the highest risks (Category B – possible risk). 4.2.1.2 Surface Water Chemicals exhibiting the highest HQs and exceeding RTVs for different receptor groups consisted of metals, diesel, and waste oil. All chemicals with HQs greater than one were similar in risk level. Copper was the only chemical exceeding acute criteria. SAC/143368(004.DOC) 4-19 ERA REPORT 7/31/02
SECTION 4: RISK CHARACTERIZATION 4.2.2 Full Tidal Potential risks were evaluated for aquatic and semi-aquatic receptors in the Full Tidal area. All chemicals with HQs exceeding one were retained as COECs (Tables 4-6 and 4-7). A summary of the potential for risk is presented below for each exposure medium. 4.2.2.1 Sediment/Soil Review of the HQs for aquatic plants indicated that metals and selected PAHs in sediments pose a possible (i.e., both no effect and low effect levels were exceeded). COECs with the highest risk potential include arsenic, barium, mercury, benzo(a)pyrene and benzo(g,h,i)perylene. For aquatic invertebrates, the highest probable risks (Category A) were observed for metals, pesticides, and PAHs/diesel. The highest HQs were observed for dieldrin, chlordane (technical, alpha, and gamma), 4,4’-DDD, 4,4’-DDE, and 4,4’-DDT. Evaluation of potential risks for semi-aquatic birds indicates that metals – cobalt, copper, zinc - and dieldrin pose possible risks. 4.2.2.2 Surface Water Chemicals exhibiting the highest HQs and exceeding RTVs for different receptor groups consisted of metals, pesticides, diesel, and waste oil. Chemicals with the highest HQs consisted of diesel, chromium, and copper. Copper and endrin were the only chemicals exceeding acute criteria. 4.2.3 Future Full Tidal Potential risks were evaluated for terrestrial, aquatic, and semi-aquatic receptors in the Future Full Tidal area. All chemicals with HQs exceeding one were retained as COECs (Tables 4-5, 4-6, and 4-7). A summary of the potential for risk is presented below for each exposure medium. 4.2.3.1 Sediment/Soil -Terrestrial Receptors Chemicals with possible risks for terrestrial plants in the Future Full Tidal area are metals and PAHs. Most exceedances had HQs greater than 10. Chemicals with the highest exceedances consisted of arsenic, barium, chromium, cobalt, copper, lead, mercury, nickel, selenium, thallium, vanadium, zinc, benzo(a)pyrene, and benzo(g,h,i)perylene. Chemicals with the highest possible risks to terrestrial invertebrates included barium, beryllium, chromium, mercury, and vanadium. Chemicals posing possible risks to upland birds and mammals included several metals. 4.2.3.2 Sediment/Soil – Aquatic Receptors Chemicals posing possible and probable risks to aquatic plants are those listed above for terrestrial plants because the two receptor groups were evaluated using the same RTVs. Estimated risks for aquatic receptors indicated that metals (cadmium, chromium, copper, lead, mercury nickel, selenium, zinc), and pesticides (4,4,’-DDD, 4,4’-DDE, 4,4’-DDT, ERA REPORT 4-20 SAC/143368(004.DOC) 7/31/02
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REVISED FINAL VOLUME I Ecological R
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CONTENTS 3. Analysis...............
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CONTENTS 3-21 Summary of EC 50 s an
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Executive Summary The Bolsa Chica L
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EXECUTIVE SUMMARY The ERA report ev
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EXECUTIVE SUMMARY “focused sampli
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EXECUTIVE SUMMARY Exposure point co
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EXECUTIVE SUMMARY sample. However,
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EXECUTIVE SUMMARY The chemicals in
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SECTION 1: INTRODUCTION • Sedimen
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SECTION 1: INTRODUCTION Assessment
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SECTION 1: INTRODUCTION Based on th
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SECTION 1: INTRODUCTION 1.5 Organiz
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SECTION 2:PROBLEM FORMULATION The L
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SECTION 2:PROBLEM FORMULATION The e
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SECTION 2:PROBLEM FORMULATION 2.2.1
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SECTION 2:PROBLEM FORMULATION tern
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SECTION 2:PROBLEM FORMULATION backg
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SECTION 2:PROBLEM FORMULATION 2.4.1
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SECTION 2:PROBLEM FORMULATION The f
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SECTION 2:PROBLEM FORMULATION Benth
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SECTION 2:PROBLEM FORMULATION Fish
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SECTION 3: ANALYSIS The field sampl
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SECTION 3: ANALYSIS CAR Sites A tot
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Page 55 and 56: SECTION 3: ANALYSIS copper were det
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Page 59 and 60: SECTION 3: ANALYSIS the subsurface
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Page 75 and 76: SECTION 3: ANALYSIS the regression
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Page 81 and 82: SECTION 3: ANALYSIS dieldrin. These
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Page 117 and 118: SECTION 6 References Abbasi, S. A.
Page 119 and 120: SECTION 6: REFERENCES Dunteman, G.
Page 121 and 122: SECTION 6: REFERENCES Kauss, P. B.
Page 123 and 124: SECTION 6: REFERENCES RareFind. 199
Page 125 and 126: SECTION 6: REFERENCES U.S. EPA. 199
Page 127: SECTION 6: REFERENCES Wentsel, R. S
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