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PAPERBACK + PDF your price: $142.50 add to cart PAPERBACK list:$121.75 Web:$109.58 add to cart PDF BOOK your price: $93.50 add to cart PDF CHAPTERS your price: $4.80 select Rights & Permissions Free Resources PDF EXECUTIVE SUMMARY Display this book on your site! Related Titles Health Risks from Dioxin and Related Compounds: Evaluation of the EPA Reassessment Models in Environmental Regulatory Decision Making Other Related Titles Science and Judgment in Risk Assessment (1994) Board on Environmental Studies and Toxicology (BEST) Web Search Builder Use this book's key terms to search within this book, across our collection, or across the Web. Skim This Chapter Skim this chapter and use this chapter's key terms to search within this book. Reference Finder Paste in your own text to find books that relate to your topic. Page 641   E-mail  Facebook  Digg  Stumble  Twitter More The following HTML text is provided to enhance online readability. Many aspects of typography translate only awkwardly to HTML. Please use the page image as the authoritative form to ensure accuracy. Page 641 Index A Acceptable daily intakes (ADIs), 30-31, 62 Acceptable risk, 3, 31, 180 Activity patterns, 5, 47, 53, 53-54, 114, 118, 119, 139 variability, 196, 199-200, 217 Age-dependent effects, 54-55, 141, 191, 219 Age-related differences, 200, 220, 511 Agency for Toxic Substances and Disease Registry, 10, 157 Aggregation, 6, 12-13, 79, 224-225, 240-242 chemical agents, 13, 89, 224-225, 226-229, 240 dose-response thresholds, 224-225, 228-229 exposure routes, 13, 41, 51-52, 119, 225-226, 240, 252 nonthreshold end points, 13, 225, 229-234, 240-241, 516-528 risk characterization, 234-240, 530-534 uncertainty, 165-166, 235-237 and variability, 13, 234, 237-240, 242, 530-534 Air-quality models, 50, 51-52, 86, 112, 114-119, 454-560, 544-545 complex terrain, 9, 115, 139, 199, 247, 249, 264, 378 Gaussian-plume models, 8, 9, 51, 52, 115, 116, 118, 119, 138-139, 140, 247, 249, 264, 376-378 industrial-source complex (ISC), 249, 377, 378, 482-483, 489, 565-566, 570-572 photochemical, 115, 118, 138 stochastic, 9, 52, 55, 116, 138-139 Ambient concentrations, 45, 86, 114, 150-151, 158 Animal studies, 26, 32, 58-60 cadmium, 100-101 carcinogens, 1, 2, 16, 59, 92-94, 92-100, 102, 229-231, 393, 395, 406-409 dioxins, 102-103 extrapolation from, 2, 5, 32, 58-59, 88-89, 119-120, 142, 210, 220, 449-451 carcinogenicity, 86, 88, 92-104, 120-126, 134, 140-142, 397, 435-436 Page 641 Front Matter (R1-R16) Executive Summary (1-15) 1 Introduction (16-22) Part I Current Approaches to Risk Assessment: 2 Risk Assessment and its Social and Regulatory Contexts (23-42) 3 Exposure Assessment (43-55) 4 Assessment of Toxicity (56-67) 5 Risk Characterization (68-78) Part II Strategies for Improving Risk Assessment: 6 Default Options (79-105) 7 Models, Methods, and Data (106-143) 8 Data Needs (144-159) 9 Uncertainty (160-187) 10 Variability (188-223) 11 Aggregation (224-242) Part III Implementation of Findings: 12 Implementation (243-268) References (269-286) Appendix A: Risk Assessment Methodologies: EPA (287-350) Appendix B: EPA Memorandum from Henry Habicht (351-374) Appendix C: Calculation and Modeling of Exposure (375-382) Appendix D: Working Paper for Considering Draft Revisions to the U.S. EPA Guidelines for Cancer Risk Assessment (383-448) Appendix E: Use of Pharmacokinetics to Extrapolate from Animal Data to Humans (449-452) Appendix F: Uncertainty Analysis of Health Risk Estimates (453-478) Appendix G: Improvement in Human Health Risk Assessment Utilizing Site- and Chemical-Specific Information: A Case Study (479-502) Appendix H-1: Some Definitional Concerns About Variability (503-504) Appendix H-2: Individual Susceptibility Factors (505-514) Appendix I: Aggregation (515-536) Appendix J: A Tiered Modeling Approach for Assessing the Risks Due to Sources of Hazardous Air Pollutants (537-582) Appendix K: Science Advisory Board Memorandum on the Integrated Risk Information System and EPA Response (583-590) Appendix L: Development of Data Used in Risk Assessment (591-598) Appendix M: Charge to the Committee (599-600) Appendix N-1: The Case for (601-628) Appendix N-2: Making Full Use of Scientific Information in Risk Assessment (629-640) Index (641-652)

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Page 641 Index A Acceptable daily intakes (ADIs), 30-31, 62 Acceptable risk, 3, 31, 180 Activity patterns, 5, 47, 53, 53-54, 114, 118, 119, 139 variability, 196, 199-200, 217 Age-dependent effects, 54-55, 141, 191, 219 Age-related differences, 200, 220, 511 Agency for Toxic Substances and Disease Registry, 10, 157 Aggregation, 6, 12-13, 79, 224-225, 240-242 chemical agents, 13, 89, 224-225, 226-229, 240 dose-response thresholds, 224-225, 228-229 exposure routes, 13, 41, 51-52, 119, 225-226, 240, 252 nonthreshold end points, 13, 225, 229-234, 240-241, 516-528 risk characterization, 234-240, 530-534 uncertainty, 165-166, 235-237 and variability, 13, 234, 237-240, 242, 530-534 Air-quality models, 50, 51-52, 86, 112, 114-119, 454-560, 544-545 complex terrain, 9, 115, 139, 199, 247, 249, 264, 378 Gaussian-plume models, 8, 9, 51, 52, 115, 116, 118, 119, 138-139, 140, 247, 249, 264, 376-378 industrial-source complex (ISC), 249, 377, 378, 482-483, 489, 565-566, 570-572 photochemical, 115, 118, 138 stochastic, 9, 52, 55, 116, 138-139 Ambient concentrations, 45, 86, 114, 150-151, 158 Animal studies, 26, 32, 58-60 cadmium, 100-101 carcinogens, 1, 2, 16, 59, 92-94, 92-100, 102, 229-231, 393, 395, 406-409 dioxins, 102-103 extrapolation from, 2, 5, 32, 58-59, 88-89, 119-120, 142, 210, 220, 449-451 carcinogenicity, 86, 88, 92-104, 120-126, 134, 140-142, 397, 435-436

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Page 642 formaldehyde, 96-99, 133 methylene chloride, 94-96 nickel compounds, 101-102 trichloroethylene (TCE), 99-100 Area sources, 3, 37, 38-39, 322, 545-546 Armitage-Doll model, 123, 202-203 Asbestos, 42n, 227, 228, 317 Atmospheric processes, see Air-quality models; Transport and fate Average values, 173, 192-193, 194, 195-196 B Bayesian models, 170, 187n Benchmark dose (BD), 64 Benign tumors, 88, 121 Benzene, 32, 33, 42n, 198, 199, 317-321 Beryllium, 42n, 317 Bias, 162, 164, 165 Bioaccumulation, 37, 40, 51, 52 Biological markers, 45, 151-152 Butadiene, 479 C Cadmium, 100-101 California, 35, 114, 152 Cancer and carcinogens, 1, 2, 16-17 animal studies, 92-100, 102, 229-231 extrapolation from, 86, 88, 92-104, 120-126, 134, 140-142, 397, 435-436 classification, 10-11, 58, 59, 60, 126-131, 142, 252, 421-427 dose-response relationship, 65-67, 85, 94-103, 236-237, 427-438 epidemiological studies, 1, 2, 16, 58, 88, 120, 207, 395, 398-404 individual species of suspect classes, 101-102 lifetime risk, 3, 19, 36, 250, 543, 552-553 mechanisms, 2-3, 9, 31, 98-99, 103, 104, 120-121, 123-126, 390-394 cell proliferation, 66-67, 99, 123, 228-229, 391-392, 415 multiple tumor risk, 13, 229-231, 240-241 regulatory approaches, 3, 17, 19, 31-33, 35, 36, 396 risk estimation, 69-70, 488-501, 552-553, 560-561, 567-568 guidelines, 34-35, 56, 87-88, 102, 236-237, 388-440, 600, 629 low-dose, 32, 85, 87, 228-229, 412-417 potency, 10, 102-103, 122-124, 126, 143, 265 unit risk estimate (URE), 10, 94, 103, 122, 124, 143, 314, 323, 543 sites of tumor formation, 121, 141 susceptibility, 200, 201-203, 207, 218-219, 505-512 synergistic interactions, 227-228, 511, 512 threshold doses, 29, 31, 65-66 Carbon monoxide, 198 Cell proliferation, 66-67, 99, 123, 228-229, 391-392, 415 Censuses of population, 113, 114 Central-tendency estimates (CTEs), 172-173, 618-621, 622, 635 Chemical Manufacturers Association (CMA), 111 Chemicals inducing alpha-2-93-94, 621 Children, 11, 210-211, 220, 252, 511 Cigarette smoke, 227-228 Clean Air Act, 3, 21, 36, 89, 91. See also Clean Air Act Amendments of 1990 Clean Air Act Amendments of 1990 (CAAA-90) Section 112 charge to NRC study committee, 4, 17-20, 82, 599-600 on environmental effects, 39-40 on individual risk calculation, 208, 217, 219

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Page 643 listed substances, 3, 36, 38, 84, 92, 145, 146, 148-149, 226, 250-251, 252, 541-542 margin-of-safety approach, 31, 37, 89, 609 on offsetting emissions, 38, 324 on role of risk- and technology-based standards, 3, 21, 28, 36-37, 38, 245, 294, 318-319, 321 Section 303 Risk Assessment and Management Commission, 19, 82, 600 Coke-oven emissions, 36, 42n Communication, see Risk characterization and communication Comparison of risk estimates, 12, 166, 183, 185-186, 260-261, 268. See also Hazard ranking; Risk ranking Complex terrain, 9, 115, 139, 199, 247, 249, 264, 378 Concentration models, see Air-quality models Continuous emission monitors (CEMs), 109 Convolution model, 380 Criticisms of risk assessment, 5-6, 40-42, 256, 258 Cumulative distribution function (CDF), 167-168 Cytochrome P450, 505-508, 510 D Data availability and quality, 9, 106, 137-138, 333-434 emissions, 9, 110, 138, 147-149 exposure, 152, 328 pollutant transport and fate, 150 population data, 112-114 toxicity assessment, 154 Data bases activity patterns, 114 emissions, 147-148, 347-348 literature reviews, 10, 253, 265 management, 156-157, 159, 266 validation, 106, 107, 254, 255 see also Integrated Risk Information System; Toxic Release Inventory Data collection priorities, 10-11, 145-146, 154-158, 344-348 emissions, 147, 155, 156 exposure, 145, 150-152, 155, 156 pollutant transport and fate, 149-150, 155, 156 toxicity assessment, 145, 153-154, 155, 156 Data needs, 6, 10-11, 79, 115, 144-145, 157-159 activity patterns, 114 emissions, 147-149, 158, 253, 591, 592 exposure, 150-152, 158, 594-596, 635 toxicity assessment, 152-154, 253, 265, 596-597 transport and fate, 149-150, 591, 593-594 see also Data availability and quality; Data collection priorities Database on Toxic Interactions, 227 Default options, 5, 7, 28-29, 32, 80-81, 85-87, 137-138 articulation of, 7, 8, 81, 87, 88-89, 104, 252, 254-255 criteria and principles, 6, 7, 8, 34, 79, 81-83, 87-90, 195 plausible conservatism, 7, 82, 83, 89, 601-626, 632-634 policy bases, 8, 81, 82, 87, 89, 104 scientific bases, 7, 8, 28-29, 82, 83, 87, 104, 610, 629-640 criticisms of, 6, 40-41, 254 departures from, 6, 7, 8, 28-29, 34, 79, 90-91, 105 criteria, 7, 8, 81, 90-91, 105, 254-255, 615-617, 629, 632-633 examples of, 92-104 petitioning, 267 scientific consensus for, 7, 8, 91, 105 and uncertainty analysis, 183-184, 185-186 extrapolation issues, 88, 90 animals to humans, 5, 88-89, 92-104

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Page 644 in iterative risk assessment, 243-244, 246-247 missing, 81, 105, 195, 207 recommendations, 8, 14, 104-105, 263, 613-617 susceptibility, 11, 207-209, 219-220, 222n, 252 see also Linearized multistage model; Maximally exposed individual Delaney clause, 17, 31 Demographics, 118, 139, 219 Detoxifying enzymes, 227, 508, 510 Developmental toxicity, 8, 234, 241 assessment guidelines, 35, 56-57, 63-64 Dibenzofurans, 103 Dioxins, 102-103 Disaggregation, 191-192, 194 Discrete variability, 503 Distribution of exposure, 5, 9, 53, 77, 204-205, 355 Dose-response assessment, 4-5, 26, 60, 152-153, 363-364 aggregation, 224-225, 228-229 carcinogens, 65-67, 85, 94-103, 236-237, 427-438 modeling, 26, 31, 103-104, 122-126, 133, 134 variability issues, 192-193, 221-222n noncancer endpoints, 60-64, 76 uncertainty issues, 62-63, 71, 163, 236-237, 241-242 see also Linearized multistage model; Potency estimates Dosimeters, 49 E Early-reduction program, 38 Elderly persons, 511 Electric Power Research Institute (EPRI), 116 Emission characterization, 5, 9, 23, 27, 47-48, 138 data availability and quality, 9, 110, 138, 147-149 data needs, 147-149, 155, 156, 158, 253, 591, 592 estimation methods, 5, 8, 48-49, 107-112 uncertainty analysis, 8, 9, 110, 112, 138, 453 itemization by chemical constituent, 111, 148 measurement methods, 5, 48-50, 109, 110-111 plant operation and disruptions, 48, 110-111, 197-198 variability, 189, 197-199 Emission factors, 48, 107, 109, 110, 111-112 Emission standards and limits, 3, 19, 20, 36 for area sources, 3, 37, 38-39, 322 for major sources, 3, 37 reporting requirements, 109, 110, 112, 148 technology-based, 3, 21, 28, 36-37, 38, 245, 294, 318-319, 321 see also Residual risk evaluation Environmental Defense Fund v. EPA, 89 Environmental effects, 38, 39-40, 226 Epidemiological studies, 26, 30, 32, 57-58, 104, 113-114, 136-137, 143, 153-154, 212, 220 cadmium, 100-101 carcinogens, 1, 2, 16, 58, 88, 120, 207, 395, 398-404 multiplicative interactions, 227-228 noncancer risks, 58, 61 susceptibility, 210 Ethyl Corp. v. EPA, 38, 89, 609 Ethylene oxide (ETO), 233, 233-234 Exponential models, 107-109, 110 Exposure, see Aggregation; Dose-response assessment; Exposure assessment; Routes of Exposure; Threshold dose hypotheses; Toxicity assessment; Variability, in exposure Exposure assessment, 3, 5, 26-27, 43-45, 48-49, 329-331, 364 calculation, 44, 375-376

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Page 645 maximally exposed individual (MEI), 9, 45, 46-47, 203-206, 217 criticisms of, 41 data needs, 145, 150-152, 155, 156, 158, 328, 594-596, 635 estimation methods, 44-45 biological markers, 45, 151-152 environmental monitoring, 26, 44-45, 150-151, 152, 158 guidelines, 44, 45, 68, 69-70, 76, 308-310 modeling, 5, 9, 44, 45, 50-55, 117-119, 139, 252, 330, 332, 376-381 activity patterns, 5, 47, 53, 53-54, 114, 118, 119, 139 Human-Exposure Model (HEM), 9, 117-119, 139, 140, 247, 319, 378-379 long-term, 54-55, 544, 547, 549-554, 558-561, 564-569 population data, 112-114, 117, 118, 139-140, 379 short-term, 55, 380-381, 544, 547, 554-557, 562-563, 569-574 uncertainty issues, 71, 163 and variability, 6, 11, 20, 79, 189, 196-200, 203-206, 216, 217-218 see also Air-quality models; Emission characterization; Routes of exposure; Transport and fate Exposure Factors Handbook, 195 Exposure-response relationship, see Dose-response assessment Extensive-hydroxylator phenotype, 200, 508 Extrapolation of data, 88, 90, 113, 220 among exposure routes, 134, 141, 450 animal to human, 2, 5, 32, 58-59, 88-89, 119-120, 142, 210, 220, 449-451 carcinogens, 86, 88, 92-104, 120-126, 134, 140-142, 397, 435-436 see also Linearized multistage model F Food Additive Amendments of 1958, Delaney clause, 17, 31 Food additives and contaminants, 30, 32 Food and Drug Administration (FDA), 32 Food chain accumulation, see Bioaccumulation Formaldehyde, 96-99, 133, 198, 199 Fugitive emissions, 47, 108-109, 111, 545-546 G Gaussian-plume models, 8, 9, 51, 52, 115, 116, 118, 119, 138-139, 140, 247, 249, 264, 376-378 Genetic mutation, 231-234, 241 Genetic susceptibility, 11, 201-203, 219, 505-511 Geographic information systems (GIS), 140, 330 Glutathione-S-transferase (GST), 95-96, 508, 510 Great Waters Study, 322-323 Guidance on Risk Characterization for Risk Managers and Risk Assessors, 20 Guidelines for risk assessment, 87, 90, 637 California, 35 carcinogens, 34-35, 56, 87-88, 102, 236-237, 388-440, 600, 629 developmental toxicity, 35, 56-57, 63-64 of EPA, 5, 34-35, 68, 104, 306-307 exposures, 44, 45, 68, 69-70, 76, 308-310 Interagency Regulatory Liason Group (IRLG), 32 Office of Science and Technology Policy (OSTP), 34, 35 Superfund sites, 35, 68, 70, 72, 73-74, 161, 226 toxicity, 56-57

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Page 646 uncertainty analysis, 12, 70, 72-75, 175-179, 185, 255-256, 257-258 see also Default options; Red Book H Habicht memorandum, 68, 76-78, 351-374 Harmonization of risk assessments, 183-184, 186 Hazard assessment, see Hazard identification; Toxicity assessment Hazard Assessment Documents (HADs), 251, 307-308, 314 Hazard identification, 4, 26, 27, 57, 152, 362-363 animal studies, 26, 32, 58-60 carcinogens, 1, 2, 16, 59, 92-94, 393, 395, 406-409 and carcinogen classification, 58, 59, 60, 126-127, 128, 421-427 epidemiological studies, 26, 32, 57-58 carcinogens, 1, 2, 16, 58, 88, 120, 395, 398-404 noncancer risks, 58, 59, 61 uncertainty issues, 71, 163 Hazard index, 69, 70, 250, 544, 557, 561, 563, 569, 572-574 Hazard ranking, 27, 37, 295, 315, 324-325 Heterogeneity dynamics, 202-203 High-end exposure estimate (HEEE), 9, 46, 47, 204-206, 217, 218, 369-370 Homeostasis, 131-132 Human-Exposure Model (HEM), 9, 117-119, 139, 140, 247, 319, 378-379 I Identifiability, 196, 213, 216-217, 503 Individual risk, 11, 69-70, 207-209, 218, 368-371 uncertainty and variability, 237-239, 532-534 Indoor sources, 9, 10, 49, 199-200, 262, 268, 379 Industrial-source complex (ISC) models, 249, 377, 378, 482-483, 489, 565-566, 570-572 Industrial Union Department, AFL-CIO v. American Petroleum Institute (Benzene decision), 33, 36 Inference guidelines, see Default options Ingestion, 226 Integrated Risk Information System (IRIS), 250-251, 261-262, 265, 323, 363-364, 583-590 Interagency Regulatory Liason Group (IRLG), 32 International Agency for Research on Cancer (IARC), 32, 58, 59, 126, 129 Iterative risk assessments, 14, 84, 89, 146, 154, 155, 157-158, 253-254, 634 emissions characterization, 147, 247, 249-250 environmental fate and transport, 149-150 exposure, 150-152, 247-250, 540-576 recommendations, 14-15, 263, 264, 266, 267 toxicity, 153-154, 250-251 L Lagrangian models, 52, 118, 138 Lead, 8 Lesser quantity emission rates (LQERs), 325-326 Lifetime cancer risk, 3, 19, 36, 250, 543, 552-553 Linearized multistage model (LMS), 9, 28, 65, 90, 103, 123, 124-125, 141-142, 613-614 departure from, 10, 28-29, 87-88, 98, 102, 142 and uncertainty analysis, 176-177 Lowest-observed-adverse-effect level (LOAEL), 30, 61-62, 63

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Page 647 M Major point sources, 3, 37, 545 Margin of safety, 30, 36 and central-tendency estimates, 618-619 under Clean Air Act, 3, 31, 36, 37, 89, 609 Mass balances, 1-7, 48, 107, 111 Material balances, see Mass balances Maximally exposed individual (MEI), 9, 37, 45, 46-47, 195, 203-206, 217 Maximum achievable control technology (MACT), 3, 37, 118, 321 Maximum tolerated dose (MTD), 120 Measurement methods, 5, 48-50, 107, 109, 110-111 Mercury, 42n, 317 Metabolic processes, 59, 94-96, 121, 122, 133-134, 411-412, 505-510 Meteorological variability, 198-199 Methylene chloride, 94-96 Microenvironments, 49, 53-54, 114, 199-200, 375-376 Missing defaults, 81, 105, 195, 207 Mixed-function oxidase (MFO) enzymes, 95-96 Mobile sources, 10, 20, 262, 268 Mobility and migration, 45, 54, 113, 118, 119, 139, 205, 217-218 Models and modeling, 9, 107-112, 137-138. See also Air-quality models; Animal studies; Default options; Dose-response assessment, modeling; Exposure assessment, modeling; Linearized multistage model; Model uncertainty; Parameter uncertainty; Pharmacokinetic models; Validation and evaluation Model uncertainty, 7, 11-12, 80, 83, 86, 87, 90, 165-166, 171-175, 185, 239 Molecular toxicology, 11, 143, 207, 219 Monitoring programs and methods, 26, 44-45, 109, 110-111, 150-151, 152 personal dosimeters, 44, 49, 151, 158 Monte Carlo models, 52, 177, 206, 330, 500 Moolgavkar-Venzon-Knudson model, 123, 195, 211 Multimedia risk assessment model, 453-461 Multiple exposure, see Aggregation Multiplicative models, 107, 109, 111 Mutagenesis, 231-234, 241 N N-acetylation polymorphism, 200, 508 National Ambient Air Quality Standard (NAAQS) Exposure Model (NEM), 117, 118, 247, 379 National Emission Standards for Hazardous Air Pollutants (NESHAPS), 42n, 72, 74-75, 166, 233 National Institute for Occupational Safety and Health, 143 National Institutes of Health (NIH), 34, 207, 219 National Research Council (NRC), see Red Book National Toxicology Program (NTP), 10, 122, 141, 157, 231-232, 251, 521, 522-523 Natural Resources Defense Council (NRDC) v. EPA, 3, 36, 37, 89, 317, 320, 609 New York, 137 Nickel, 101-102 Noncancer risks, 10, 39-40, 41, 58, 59, 61, 69-70, 76, 131-132, 142 dose-response assessment, 60-64, 76 nonthreshold, 231-234, 241 Noninhalation exposures, 10, 44, 119, 140, 226 Nonthreshold end points, 225, 229-234, 240-241, 516-528 No-observed-adverse-effect level (NOAEL), 30, 39, 61-64, 132, 142, 323

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Page 648 No-observed-effect level (NOEL), 30, 41, 61 Numerical integration, 177 O Occupational exposure and regulation, 30, 32, 33, 143 Occupational Safety and Health Administration (OSHA), 32, 33 Office of Air Quality Planning and Standards (OAQPS), EPA, 261, 268, 307-308, 309, 311, 329-330, 579 Office of Research and Development (ORD), EPA, 261, 268, 307 Office of Science and Technology Policy (OSTP), 34, 35 Offsetting emissions, 38, 260, 324 Ozone, 198, 200 P Parameter uncertainty, 74-75, 86, 165, 172, 173-175, 185, 187n, 238-239, 256, 454, 457-459, 614 Pathways of exposure, see Routes of exposure Peak-concentration sampling, 151 Peer review, 8, 91, 105, 261, 296-297, 617 Permissible exposure level (PEL), 62 Peroxisome proliferation, 100 Personal activity, see Activity patterns Personal monitors, 44, 49, 151, 158 Pesticides, 30, 32, 35, 39 Pharmacokinetic models, 95, 125-126, 220-221 physiologically based (PBPK), 66, 95, 96, 122, 165, 211-212, 431, 449-451, 617 in toxicity assessment, 2-3, 9-10, 66, 132-136, 141-142 Pharmacodynamics, 66, 125, 141-142 Photochemical air-quality models, 115, 118, 138 Physiologically based pharmacokinetic models (PBPK), 66, 95, 96, 122, 165, 211-212, 431, 449-451, 617 Plant operations and disruptions, 48, 110-111, 197-198 Plant Organization Software System (POSSEE), 111 Plausible conservatism, 7, 82, 83, 89, 237, 601-626, 632-634 Point estimates, 53, 110, 218 aggregation of, 235-236, 241-242 and risk management, 12, 41, 166-167, 179-181, 184-185 Pollutant transport and fate, see Airquality models; Transport and fate Polycyclic aromatic hydrocarbons (PAHs), 506-507, 508 Polymorphic phenotypes, 200, 505-510 Population data and models, 112-114, 117, 118, 139-140, 379 mobility, 45, 54, 113, 118, 119, 139, 205, 217-218 Population risk, 70, 209-210, 218, 371-372 children, 11, 210-211, 220, 252, 511 subgroup exposure and susceptibility, 11, 114, 191, 205, 253, 372-373 uncertainty and variability, 239-240, 531-532 Potency estimates, 10, 27, 38, 102-103, 122-124, 126, 143, 265 uncertainty analysis, 10, 143, 162 unit cancer risk, 10, 103, 122, 124, 143 variability, 189, 193, 218-219 Probability density function (PDF), 167-168, 171-175, 184, 186 Probability distributions, 161, 167-178, 180, 184, 454 generation of, 175-177, 465-467 subjective, 83, 170-171, 177, 178 Process-vent emissions, 47, 109 Public criticisms, see Criticisms of risk assessment R Race and ethnicity, 7, 114, 219 Radiomimetic activity, 2, 9, 31, 103, 125

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Page 649 Radon, 227-228 Randomness, 162, 164, 165 Red Book (1983 NRC report), 25, 33-34, 160 on default options, 85, 86-87, 90-91 risk assessment framework, 4-5, 23-24, 26-27, 306, 396, 637 on risk management, 5, 34, 41, 260 Reference concentrations (RfCs), 39, 70, 250, 265, 323, 543 Reference dose (RfD), 62, 63, 70, 142, 311-312 Regulatory policy and decision-making, 2, 3, 5, 7, 17, 18, 28, 36-39, 258-259 and carcinogens, 17, 31-33, 35, 396 and public perception, 262-263 resource allocation, 2, 19, 28, 246, 631 see also Default options; Emission standards and limits; Risk management Reproductive toxicity, 8, 63, 234, 241 Research activities and agendas, 27-28, 261-262, 268, 611-612, 617-618, 630, 638, 640 Residual risk evaluation, 3, 21, 37, 101, 118, 180, 245, 321, 327, 329, 540, 542 Resource Conservation and Recovery Act (RCRA), 35 Risk Assessment and Management Commission, 19, 82, 600 Risk Assessment in the Federal Government: Managing the Process, see Red Book Risk characterization and communication, 5, 23, 27, 68, 78, 80, 181, 183, 439-440, 630-631 and aggregation, 234-240, 530-534 EPA (Habicht) memorandum, 68, 76-78, 351-374 full disclosure, 77, 352-353, 355, 361-367 to managers, 13, 78, 80, 83-84, 310-312, 614-615, 630-632 presentation of estimates, 69-70, 76-78, 83-84, 351-374, 624-625 professional judgment, 77, 354 to public, 78, 144-145, 194, 252 recommendations, 13-14, 263 uncertainty analysis, 12, 15, 20, 27, 41, 70-75, 78, 83-84, 174, 180, 235-240, 263, 310-312, 362, 365-366 use of multiple descriptors, 77, 353-354, 355, 367-374 of variability, 11, 194, 212-213, 214-215, 221 Risk management, 18, 19, 28, 32, 41-42, 349-350, 360-361, 630-632 communication of risk to, 13, 78, 80, 83-84, 310-312, 614-615, 630-632 risk-reduction strategies, 196, 262 safety-factor approach, 30-31 separation from risk assessment, 5, 34, 77, 259-260, 267-268, 355, 358-360, 623 and uncertainty analysis, 41, 166-167, 171-175, 179-183 Risk ranking, 27, 37, 171, 183, 186-187, 296, 315, 325-326, 617 Rodents, 122, 141, 143 Routes of exposure, 10, 26-27, 43-44, 119, 140 extrapolation among, 134, 141, 450 multiple, 13, 41, 51-52, 119, 225-226, 240, 252 noninhalation, 10, 44, 119, 140, 226 and site of tumor formation, 121 S Safety-factor method, 30-31, 62-63, 224 Sampling, 109, 151 Science Advisory Board (SAB), EPA, 7, 8, 91, 105, 617 Screening assessments, 9, 14, 84, 156, 159, 217, 242, 245-246, 263, 326-327, 544, 549-563 Simulation of Human Air Pollution Exposure (SHAPE) Model, 117, 118, 379-380 Single point estimates, see Point estimates Site-specific data, 10, 109, 147-149, 158

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Page 650 Source Category Ranking System (SCRS), 325 Sources of hazardous pollutants, 3, 37, 47-48, 54, 545 area sources, 3, 37, 38-39, 322, 545-546 indoor, 9, 10, 49, 199-200, 262, 268, 379 mobile, 10, 20, 262, 268 Spatial variability, 191-192, 197-198 State Activity Pattern Study, 114 State government, 10, 42, 152, 157 State implementation plans (SIPs), 147-148 Stochastic modeling, 9, 52, 55, 116, 138-139 Storage-tank emissions, 47-48, 111 Strength of evidence, 10, 126-127, 128, 129 Structured activity relationships (SARs), 410-411 Subjective probability distributions, 83, 170-171, 177, 178 Subpopulation exposures and risk, 11, 114, 191, 205, 253, 372-373 Superfund Amendments and Recovery Act (SARA), 147, 148, 158, 313 Superfund-site risk assessment, 35, 68, 70, 72, 73-74, 161, 226 Susceptibility, 11, 30, 207-209, 219-220, 222n, 252 age-related, 200, 220, 511 to cancer, 200, 201-203, 207, 218-219, 505-512 genetic, 11, 201-203, 219, 505-511 identification of high-risk individuals, 196, 213, 216-217, 503 variability in, 6, 11, 40, 79, 196, 206-210, 213, 216-217, 218-221 Synergistic interactions, 40, 227-228, 511, 512 Systematic bias, 165 T Targeted fixed-point monitoring, 151 Technology-based regulation, 3, 21, 28, 31, 33, 36-37, 38, 245, 294, 318-319, 321 Temporal variability, 191, 197-198 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), 102-103 Theoretical upper-bound exposure (TUBE), 9, 46-47, 204 Threshold dose hypotheses, 8, 29-31, 39, 62-64, 131-132 multiple chemical exposure, 224-225, 228-229 Threshold limit values (TLVs), 30 Tiered modeling approach, 243-244, 326-327, 329. See also Iterative risk assessments Time-activity patterns, 47, 53, 114 Total Exposure and Assessment Methodology (TEAM), 49, 114, 117 Toxic-equivalency factor (TEF) method, 103 Toxicity assessment, 2-3, 23, 56-57, 295, 314, 323-324 carcinogen classification, 10-11, 126-131, 142, 252 carcinogens, 397-427 animal studies, 120-126, 140-142, 397 data needs, 145, 152-154, 155, 156, 253, 265, 596-597 extrapolation of animal studies, 119-120, 120-126, 140-142, 142 noncancer endpoints, 10, 131-132, 142 nonthreshold, 231-234, 241 pharmacokinetic models, 2-3, 9-10, 66, 132-136, 141-142 see also Dose-response assessment; Hazard identification; Potency estimates Toxic Release Inventory (TRI), 147-149, 158, 313 Toxic Substances Control Act (TSCA), 35 Transfer emissions, 48 Transport and fate, 23, 145-146 data needs, 149-150, 155, 156, 591, 593-594

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Page 651 variability, 189, 197, 198-199 see also Air-quality models; Exposure assessment Trichloroethylene (TCE), 99-100 Two-stage model, 123-124, 125 U Uncertainty, 11-12, 27, 28, 70, 137, 160-166, 252 communication of, 12, 15, 20, 27, 41, 70-75, 78, 83-84, 174, 180, 235-240, 263, 310-312, 362, 365-366 in dose-response assessment, 62-63, 71, 163, 236-237, 241-242 in emissions estimation, 8, 9, 110, 112, 138, 453 EPA approach, 6, 70, 72-75, 79, 166-167 in exposure assessment, 71, 163 guidance on analysis, 12, 70, 72-75, 175-179, 185, 255-256, 257-258 in hazard identification, 71, 163 in population data, 113-114 probability distributions, 161, 167-178, 180, 184, 454 generation of, 175-177, 465-467 recommendations, 12, 167, 168, 184-187 in Superfund-site assessments, 70, 72, 73-74, 161 and variability, 11, 162, 164, 180-181, 187n, 213, 221, 237-240, 242 see also Default options; Model uncertainty; Parameter uncertainty Uncertainty-factor approach, 39, 62-63, 142, 224 Unit risk estimate (URE), 10, 94, 103, 122, 124, 143, 314, 323, 543 Unleaded gasoline, 92 V Validation and evaluation, 6, 8-10, 79, 106-107, 136-143, 254-255 air-quality models, 114-119, 138-139 data bases, 106, 107, 254, 255 exposure models, 49-50, 114, 139-140, 264 extrapolation of animal studies, 119-136, 140-142, 212 Variability, 11, 188-191, 189, 195, 196, 221n in biological characteristics, 211-212, 220 communication of, 11, 194, 212-213, 214-215, 217-221 disaggregation, 191-192, 194 in emissions, 189, 197-199 in exposure, 6, 11, 20, 79, 189, 196-200, 203-206, 216, 217-218 activity patterns, 196, 199-200, 217 ignoring, 191, 194, 220 intraindividual, 11, 189 management strategies, 191-196 in potency, 189, 193, 218-219 spatial, 191-192, 197-198 in susceptibility, 6, 11, 40, 79, 206-210, 216-217, 218-221 to cancer, 200, 201-203, 207, 218-219, 505-512 defaults, 11, 207-209, 219-220, 222n, 252 distributions and dichotomies, 201-203, 206-210, 503 factors in, 200-201, 503-512 identifiable, 196, 213, 216-217, 503 temporal, 191, 197-198 and uncertainty, 11, 162, 164, 180-181, 187n, 213, 221, 237-240, 242 use of averages, 192-193, 194, 195-196 use of high end values, 193, 195-196, 217 Variance-component model, 380-381 Vinyl chloride, 42n, 133-134, 317, 320 Volatile organic compounds (VOCs), 111, 148, 149, 150 W Weight of evidence (WOE), 76, 126, 128, 311-312 Workshops, 8, 91, 105, 617 Worst-case exposures, 195-196, 369

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Representative terms from entire chapter:

uncertainty analysis