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SECTION 4: RISK CHARACTERIZATION Aquatic Invertebrates Acute effect levels (probable risk – Category A) were exceeded by 2 inorganic and 6 organic chemicals (Table 4-3). The ER-M was exceeded by 4,4’-DDD, 4,4’-DDE, chlordane (technical), chlordane-alpha, and total DDT. The HQs for these chemicals ranged from 1.2 to 3.6. The LC 50 was exceeded by selenium, thallium, and phenanthrene with HQs ranging from 1 to 1.9. Several chemicals showed possible risk (Category B) including 8 inorganics and 11 organics. The HQs for all these chemicals are less than 10. Both the ER-L and LC 20 were exceeded by nickel. Copper, lead, mercury, chlordane-gamma, and dieldrin exceeded the ER-L but not the LC 20 with HQs ranging from 1.0 (copper) to 60 (dieldrin). Beryllium, cobalt, thallium, vanadium, zinc, and 10 of the 11 organics exceeded the LC 20 but not the ER-L. HQs among this group ranged from 1.2 (vanadium) to 11 (for selenium). Several chemicals had some possible risk (Category C) or uncertain risk (Category U). Category C chemicals included 3 metals and 5 organics which were all PAHs. The NOEC HQs for these chemicals ranged from 2.3 (chrysene) to 71 (benzo(a)anthracene. The Category U chemicals had NOEC HQs ranging from 3.5 (barium) to 100 (indeno(1,2,3-cd)perylene. Semi-Aquatic Birds Risk estimates for semi-aquatic birds (Table 4-2) indicated that metals and pesticides pose the greatest potential for adverse effects. Terns were the most sensitive receptor with the exception of exposure to barium and cadmium for which the heron was more sensitive. As noted previously for the Future Full Tidal area, this is due to differences in concentrations of chemicals present in site-collected biota and the differences in dietary composition between the two receptors. Chemicals that showed possible risk (Category B) included cobalt, copper, lead, zinc, 4,4’-DDE, for both herons and terns as well as Aroclor 1254 for terns. The NOAEL HQs for these chemicals ranged from 1.9 for copper (heron) to 286 for zinc (tern). The LOAEL HQs ranged from 1.5 for copper (heron) to 858 for 4,4’-DDE (tern). Chemicals with some possible risk (Category C) included cadmium for heron and tern, and cobalt and lead for stilt. Several chemicals had uncertain risks (Category U) including barium, chromium, selenium, vanadium, 4,4’-DDD, and dieldrin. The NOAEL HQs for these chemicals ranged from 1.2 for chromium (stilt) to 300 for selenium (tern). 4.1.2.5 Gas Plant Pond Area Aquatic Plants Estimates of potential risk to aquatic plants in sediments of the Gas Plant Pond Area indicated that risks are primarily a result of metals and PAHs (Table 4-1). COPECs detected in the Gas Plant Pond Area that exceeded available chronic NOECs for aquatic plants consisted of selenium and nickel with HQs of 11 and 1.7, respectively. Chronic LOECs were exceeded by 11 chemicals indicating a possible risk (Category B). Of these chemicals, arsenic (41), benzo(g,h,i) perylene (23), and benzo(a)pyrene (21) had the highest HQs. Of those chemicals exceeding chronic LOECs, 5 were evaluated using an exposure point concentration that was ½ the reporting limit for a non-detect. SAC/143368(004.DOC) 4-11 ERA REPORT 7/31/02
SECTION 4: RISK CHARACTERIZATION Aquatic Invertebrates There were 4 inorganic and 14 organic chemicals that showed probable risk (Category A) by exceeding acute toxicity levels (Table 4-3). Chemicals that exceeded both the ER-M and the LC 50 included fluorene, phenanthrene, and low MW PAHs. The HQs for these chemicals ranged from 1.0 (phenanthrene) to 367 (fluorene). The HQs for comparisons to the ER-M tended to be lower than those for comparisons to the LC 50 . The largest difference occurs with fluorene, for which the ER-M HQ was 6.7 and the LC 50 HQ was 367. This indicates that the LC 50 s for some chemicals may be overestimated depending on the availability of data. The HQs for other chemicals exceeding either the ER-M or the LC 50 were all less than 10. Possible risk (Category B), whereby the ER-L or the LC 20 value for amphipod toxicity was exceeded, was observed for 9 inorganic and 5 organic chemicals. Both the ER-L and LC 20 were exceeded by nickel, zinc, and chrysene with HQs all below 2. The HQs for these chemicals were comparable between the ER-Ls and LC 20 s. Other chemicals exceeding the ER-L included copper, lead, mercury, silver, 4,4’-DDE, benzo(a)anthracene, and dieldrin with HQs ranging from <strong>1.1</strong> (silver) to 105 (dieldrin). Other chemicals exceeding the LC 20 consisted of beryllium, cobalt, and benzo(b)fluoranthene with HQs ranging from 1.4 (cobalt) to 7.1 (benzo[b]fluoranthene). Some possible risk (Category C) was observed for cadmium, benzo(a)pyrene, fluoranthene, pyrene, and high MW PAHs. These were all based on exceeding the no-effect level (Nereis NOEC), but not a low-effect level. The HQs for these chemicals ranged from 2.3 (high MW PAHs) to 102 (fluoranthene). Similarly, several chemicals (1 inorganic and 8 organics) showed uncertain risk (Category U) since the Nereis NOEC was the only RTV available. Three toxicity bioassays were conducted using the marine amphipod (Eohaustorius estuarius) with sediment collected from the ponds downgradient from the former Gas Plant (Table 3-14). Two samples were significantly different from controls for survival. None were significantly different for reburial. Semi-Aquatic Birds Risk estimates for semi-aquatic birds indicated that metals and pesticides pose the greatest potential for adverse effects (Table 4-2). The tern was the most sensitive receptor in most cases followed by the heron. Herons were more sensitive to arsenic and equally sensitive to cadmium. The stilt was the least sensitive, with only one exceedance for chromium. Chemicals with possible risk (Category B) consisted of cobalt, copper, lead, zinc, 4,4’-DDE, and Aroclor 1254 (heron and tern). The NOAEL HQs for these chemicals ranged from 2.9 for copper (heron) to 318 for zinc (tern). The LOAEL HQs ranged from <strong>1.1</strong> for Aroclor 1254 (heron) to 184 for 4,4’-DDE (tern). Two chemicals, arsenic (heron) and cadmium (heron and tern), showed some possible risk (Category C), and several chemicals showed uncertain risks (Category U). The NOAEL HQs for the Category U chemicals ranged from 1.4 for chromium (stilt) to 663 for selenium (tern). 4.1.2.6 Muted Tidal plus Rabbit Island Aquatic Plants Potential risks to aquatic plants were estimated through comparison to RTVs for terrestrial plants (Table 4-1). Calculation of HQs indicate that potential risks are primarily as a result of metals and PAHs. Both nickel and selenium exceeded chronic NOECs for aquatic plants ERA REPORT 4-12 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
Page 41 and 42: SECTION 2:PROBLEM FORMULATION Benth
Page 43 and 44: SECTION 2:PROBLEM FORMULATION Fish
Page 45 and 46: SECTION 3: ANALYSIS The field sampl
Page 47 and 48: SECTION 3: ANALYSIS CAR Sites A tot
Page 49 and 50: SECTION 3: ANALYSIS 3.1.2 Data Eval
Page 51 and 52: SECTION 3: ANALYSIS questionable. T
Page 53 and 54: SECTION 3: ANALYSIS Pesticides were
Page 55 and 56: SECTION 3: ANALYSIS copper were det
Page 57 and 58: SECTION 3: ANALYSIS For five of the
Page 59 and 60: SECTION 3: ANALYSIS the subsurface
Page 61 and 62: SECTION 3: ANALYSIS 3.1.4 Exposure
Page 63 and 64: SECTION 3: ANALYSIS 3.1.4.2 Exposur
Page 65 and 66: SECTION 3: ANALYSIS Model The gener
Page 67 and 68: SECTION 3: ANALYSIS 3.1.5 Exposure
Page 69 and 70: SECTION 3: ANALYSIS The toxicity bi
Page 71 and 72: SECTION 3: ANALYSIS The chronic tox
Page 73 and 74: SECTION 3: ANALYSIS conductivity wi
Page 75 and 76: SECTION 3: ANALYSIS the regression
Page 77 and 78: SECTION 3: ANALYSIS Scatter plots a
Page 79 and 80: SECTION 3: ANALYSIS concentrations,
Page 81 and 82: SECTION 3: ANALYSIS dieldrin. These
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Page 111 and 112: CHAPTER 5: SUMMARY, CONCLUSIONS, AN
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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