1.1 MB pdf - Bolsa Chica Lowlands Restoration Project

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CHAPTER 5: SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS The evaluation of background levels for inorganic constituents in sediments was completed using samples collected from onsite focused and random sample locations (including those within the proposed dredge area footprint). Maximum concentrations of chemicals considered to be background levels in surface and subsurface sediments and a combined value for all sediments were estimated; this was accomplished using cumulative distribution plots in which detected and non-detected results were evaluated together and separately to distinguish the impact of non-detected results on the distribution and estimated background concentrations. Maximum background values for the combined data set were estimated for arsenic (11 mg/Kg), barium (110 mg/Kg), beryllium (0.94 mg/Kg), cadmium (0.66 mg/Kg), chromium (43 mg/Kg), cobalt (10.1 mg/Kg), copper (26.1 mg/Kg), lead (48 mg/Kg), mercury (0.28 mg/Kg), nickel (30 mg/Kg), selenium (0.54 mg/Kg), silver (0.22 mg/Kg), thallium (0.61 mg/Kg), vanadium (75 mg/Kg), and zinc (103 mg/Kg). These site specific background levels were higher (2 to 6 times) than the preliminary background used in the Scoping Assessment (Table 2-12). The exposure profile outlined the receptors and exposure routes that were most likely to occur at the <strong>Lowlands</strong>, and the basis for the exposure point concentration as listed below: • Terrestrial plants - Direct contact via root uptake from sediment/soil. Exposure point concentrations based on the maximum reported value for each chemical detected. • Terrestrial invertebrates - Direct contact with and ingestion of sediment/soil. Exposure point concentrations based on the maximum reported value for each chemical detected. • Belding's savannah sparrow - Ingestion of terrestrial plants, terrestrial invertebrates, sediment/soil, and surface water. Exposure point concentrations based on the 95 th UCL value for each chemical detected. • American kestrel - Ingestion of terrestrial invertebrates, small mammals, sediment/soil, and surface water. Exposure point concentrations based on the 95 th UCL value for each chemical detected. • Black-crowned night-heron - Ingestion of aquatic invertebrates, fish, small mammals, sediment/soil, and surface water. Exposure point concentrations based on the 95 th UCL value for each chemical detected. • Black-necked stilt - Ingestion of aquatic invertebrates, sediment/soil, and surface water. Exposure point concentrations based on the 95 th UCL value for each chemical detected. • Least tern - Ingestion of fish, sediment/soil, and surface water. Exposure point concentrations based on the 95 th UCL value for each chemical detected. • Western harvest mouse - Ingestion of terrestrial plants, invertebrates, sediment/soil, and surface water. Exposure point concentrations based on the 95 th UCL value for each chemical detected. • Coyote - Ingestion of terrestrial plants, bird eggs, small mammals, sediment/soil, and surface water. Exposure point concentrations based on the 95 th UCL value for each chemical detected. SAC/143368(005.DOC) 5-3 ERA REPORT 7/31/02
CHAPTER 5: SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS • Aquatic plants – Direct contact/root uptake from sediment/soil and surface water. Exposure point concentration based on the maximum reported value for each chemical detected. • Aquatic macroinvertebrates - Direct contact with and ingestion of sediment/soil. Exposure point concentration based on the maximum reported value for each chemical detected. • Fish - Direct contact with surface water. Exposure point concentration based on the maximum reported value for each chemical detected. Ecological Effects Characterization The Ecological Effects Characterization focused on (1) evaluating site-specific effects data to determine the potential adverse effects that may result from different concentrations of chemical stressors, and (2) establishing a link between these effects and the assessment endpoints and ecological conceptual site model. The product of this portion of the ERA was the stressor-response profile that was combined with the exposure profile to conduct the Risk Characterization. The stressor-response profile summarized the potential effect levels for different receptors that are related to the assessment endpoints for the ERA. These effect levels included: • NOECs, NOAELs, LOECs, LOAELs and other toxicity-based endpoints – Obtained from the literature for terrestrial receptors (plants, invertebrates, birds, and mammals) (see Tables 3-25 through 3-28) • LC 20 s and LC 50 s for survival of aquatic invertebrates in sediment – Derived from the regression analyses conducted on amphipod toxicity bioassay results. (See Table 3-29) • NOECs for survival of aquatic invertebrates in sediment – Calculated from polychaete worm toxicity bioassay results (see Table 3-29) • EC 20 s and EC 50 s for larval development of aquatic invertebrates in pore water – Derived from the regression analyses conducted on bivalve toxicity bioassay results (see Table 3-30) • NOECs for survival and growth of fish in surface water – Calculated from fish toxicity bioassay results (see Table 3-30) • NOECs and/or LOECs for survival, growth, reproduction, and/or fecundity for aquatic invertebrates - Calculated from Ceriodaphnia and Mysidopsis toxicity bioassay results (see Table 3-30). Risk Characterization The Risk Characterization presents the evidence linking COPECs to potential adverse effects in the <strong>Lowlands</strong> including calculation of HQs and evaluation of site-specific toxicity bioassays and bioaccumulation studies to provide a weight-of-evidence for potential risks and identify COECs. The identification of COECs was presented in Figure 4-1. All COPECs that exceeded any available RTV as well as chemicals that showed significant bioaccumulation in Nereis clam worms were retained as COECs. The overall risk posed by a COEC in a given medium ERA REPORT 5-4 SAC/143368(005.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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SECTION 3: ANALYSIS 3.1.2 Data Eval
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SECTION 3: ANALYSIS questionable. T
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SECTION 3: ANALYSIS Pesticides were
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SECTION 3: ANALYSIS copper were det
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SECTION 3: ANALYSIS For five of the
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SECTION 3: ANALYSIS the subsurface
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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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