1.1 MB pdf - Bolsa Chica Lowlands Restoration Project

More documents

Recommendations

Info

SECTION 3: ANALYSIS preliminary screening. As expected, the corresponding number of Cells where the secondary screening levels (ER-Ms or LC 50 s) were exceeded was much smaller than for the preliminary screening level. Chemical group-specific discussions are presented below: Metals Exceedances of the preliminary screening levels (LC 20 , ER-L, or background levels) were observed in most Cells within the Bolsa Chica Lowlands. Exceedances of the preliminary screening levels were not observed in the seven Cells listed above or in Cell 6, Cell 37, Cell 49, Cell 58, or Cell 60 (Figure 3-7). One or more exceedances of the ER-M for individual metals were observed in only 4 Cells: Cell 1A, Cell 3, Cell 34, and Cell 35 (Figure 3-8). Petroleum Hydrocarbons Exceedances of the preliminary screening levels (LC 20 or ER-L) were observed in most Cells within the Bolsa Chica Lowlands. Exceedances of the preliminary screening levels were not observed in the seven Cells listed above or in Cell 9, Cell 10, Cell 13, Cell 19, Cell 25, Cell 31, Cells 38 through 45, Cell 50, Cell 51, Cell 61, Cell 62, or Cell 67 (Figure 3-9). One or more exceedances of the secondary screening levels (LC 50 ) for petroleum hydrocarbons were observed in only 6 Cells: Cell 1A, Cell 3, Cell 4, Cell 21, Cell 34, and Cell 36 (Figure 3-10). Chlorinated Pesticides Exceedances of the preliminary screening levels (LC 20 or ER-L) were observed in most Cells within the Bolsa Chica Lowlands. Exceedances of the preliminary screening levels were not observed in the seven Cells listed above or in Cell 4, Cell 6, Cell 14, Cell 21, Cell 25, Cell 31, Cell 37, Cell 39, Cell 47, Cell 62, or Cell 67 (Figure 3-11). One or more exceedances of the secondary screening levels (ER-M) for chlorinated pesticides were observed in 11 Cells: Cell 1, Cell 15, Cell 26, Cell 30, Cell 32, Cell 35, Cell 42, Cell 46, Cell 52, Cell 53, and Cell 58 (Figure 3-12). PCBs Exceedances of the preliminary screening levels (LC 20 or ER-L) were observed in fewer Cells within the Bolsa Chica Lowlands than for other chemical groups. Exceedances of the preliminary screening levels were observed in 6 Cells: Cell 1A, Cell 26, Cell 34, Cell 36, Cell 47, and Cell 52, as well as Inner Bolsa Bay (Figure 3-13). One or more exceedances of the secondary screening levels (ER-M) for PCBs were observed in only 2 Cells, Cell 26 and Cell 47 (Figure 3-14). Phthalates Exceedances of the preliminary screening levels (LC 20 ) were observed in fewer Cells within the Bolsa Chica Lowlands than for other chemical groups except PCBs. Exceedances of the preliminary screening levels were observed in 15 Cells: Cell 1A, Cell 3, Cell 7, Cell 9, Cell 12, Cell 21, Cell 26, Cell 32, Cell 34, Cell 36, Cell 42, Cell 45, Cell 48, Cell 49, and Cell 63, as well as Inner and Outer Bolsa Bay (Figure 3-15). One or more exceedances of the secondary screening levels (LC 50 ) for phthalates were observed in only 3 Cells: Cell 7, Cell 21 and Cell 36 (Figure 3-16). SAC/143368(003.DOC) 3-19 ERA REPORT 7/31/02
SECTION 3: ANALYSIS 3.1.4.2 Exposure Point Concentrations A conservative approach was used to define the exposure point concentrations for receptors in the Bolsa Chica Lowlands due to the future uses of the Lowlands as mitigation habitat and a wildlife refuge. The exposure point concentrations for abiotic media (intake or contact with sediment/soil, surface water, and pore water) were calculated based on the mobility of the receptor being evaluated and the availability of data (i.e., were sufficient samples available to calculate specific statistics?). The exposure point concentrations for biotic exposure media (i.e., intake of food items) were calculated from data collected over the entire site for each tissue type. This combination of tissue data was used primarily because the higher trophic level receptors are not limited to foraging within a single cell and may forage throughout the site. Abiotic Exposure Media The exposure point concentrations for abiotic exposure media (sediment/soil and surface water) that will be used in exposure and risk estimates for terrestrial and aquatic plants and invertebrates are the maximum detected concentration for each detected chemical in each evaluation area (e.g., Full-tidal). This value was selected because plants and invertebrates are either immobile or relatively sedentary receptors, so they do not spatially average their exposure over the medium in which they reside (Suter et al., 2000). The exposure point concentrations for fish were selected based on the physical limitations to their mobility (they are unable to move between cells), and the limited availability of surface water data. For most analytes and evaluation areas, sample sizes were not greater than 5 samples (Table 3-3) precluding the calculation of a 95-percent UCL. In addition, reference toxicity values were not available for some chemicals with greater than 5 samples (e.g., TPH diesel and waste oil). Based on the future uses of the Lowlands, the limited mobility of fish in the Lowlands, and the availability of surface water data, the observed maximum concentrations detected in each evaluation area were selected as the exposure point concentrations for fish. The exposure point concentrations for birds and mammals are the 95-percent UCLs of the arithmetic mean where a 95th UCL could be calculated and it was lower than the maximum reported concentration. If a 95th UCL could not be calculated or it was greater than the maximum, the maximum detected concentration was used. Duplicate samples were treated as unique samples and the maximum detected concentration (regardless of whether the duplicate or the original sample had the higher value) was used. The exposure point concentrations for abiotic media (i.e. maximum detected values and 95-percent UCLs) were presented in Table 3-2 (sediment/soil) and Table 3-3 (surface water). The use of maximum exposure concentrations was carefully considered along with the less conservative alternative approach of using the mean or the 95-percent UCL of the mean. The selected approach is consistent with standard practice. Plants and invertebrates are immobile or relatively sedentary receptors, so it is not reasonable to assume that they spatially average their exposure over the medium in which they reside (Suter et al., 2000). To determine which chemicals at the site may require cleanup, the maximum concentration is the most appropriate exposure measure. Because this site is intended to serve as mitigation habitat, and because it will become a wildlife refuge once remediation is complete, this approach is appropriate. ERA REPORT 3-20 SAC/143368(003.DOC) 7/31/02
Page 1 and 2:
REVISED FINAL VOLUME I Ecological R
Page 3 and 4:
CONTENTS 3. Analysis...............
Page 5 and 6:
CONTENTS 3-21 Summary of EC 50 s an
Page 7 and 8:
Executive Summary The Bolsa Chica L
Page 9 and 10:
EXECUTIVE SUMMARY The ERA report ev
Page 11 and 12: EXECUTIVE SUMMARY “focused sampli
Page 13 and 14: EXECUTIVE SUMMARY Exposure point co
Page 15 and 16: EXECUTIVE SUMMARY sample. However,
Page 17 and 18: EXECUTIVE SUMMARY The chemicals in
Page 19 and 20: SECTION 1: INTRODUCTION • Sedimen
Page 21 and 22: SECTION 1: INTRODUCTION Assessment
Page 23 and 24: SECTION 1: INTRODUCTION Based on th
Page 25 and 26: SECTION 1: INTRODUCTION 1.5 Organiz
Page 27 and 28: SECTION 2:PROBLEM FORMULATION The L
Page 29 and 30: SECTION 2:PROBLEM FORMULATION The e
Page 31 and 32: SECTION 2:PROBLEM FORMULATION 2.2.1
Page 33 and 34: SECTION 2:PROBLEM FORMULATION tern
Page 35 and 36: SECTION 2:PROBLEM FORMULATION backg
Page 37 and 38: SECTION 2:PROBLEM FORMULATION 2.4.1
Page 39 and 40: 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: SECTION 3: ANALYSIS 3.1.4 Exposure
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
Page 83 and 84: SECTION 4: RISK CHARACTERIZATION Ha
Page 85 and 86: SECTION 4: RISK CHARACTERIZATION Te
Page 87 and 88: SECTION 4: RISK CHARACTERIZATION to
Page 89 and 90: SECTION 4: RISK CHARACTERIZATION te
Page 91 and 92: SECTION 4: RISK CHARACTERIZATION Se
Page 93 and 94: SECTION 4: RISK CHARACTERIZATION Aq
Page 95 and 96: SECTION 4: RISK CHARACTERIZATION 4.
Page 97 and 98: SECTION 4: RISK CHARACTERIZATION pl
Page 103 and 104: SECTION 4: RISK CHARACTERIZATION Po
Page 107 and 108: SECTION 4: RISK CHARACTERIZATION De
Page 109 and 110: SECTION 4: RISK CHARACTERIZATION no
Page 111 and 112: CHAPTER 5: SUMMARY, CONCLUSIONS, AN
Page 113 and 114:
CHAPTER 5: SUMMARY, CONCLUSIONS, AN
Page 115 and 116:
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
show all

1.1 MB pdf - Bolsa Chica Lowlands Restoration Project

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?