Public Health Risk Assessment for Human Exposure to Chemicals

by Asante-Duah, Kofi

• ISBN13: 9781402009211
• ISBN10: 1402009216
• Format: Paperback
• Copyright: 2002-11-01
• Publisher: Kluwer Academic Pub

Summary

Risks to humans as a consequence of chemical exposures are a complex issue with worldwide implications, especially in our modern societies. The effective management of human exposure to a variety of chemicals present in various sectors of society has indeed become a very important public health policy issue - and risk assessment promises a systematic way for developing appropriate strategies to aid public health risk management decisions. Risk assessment generally serves as a tool that can be used to organize, structure, and compile scientific information in order to help identify existing hazardous situations or problems, anticipate potential problems, establish priorities, and provide a basis for regulatory controls and/or corrective actions. In fact, with the control and containment of most infectious conditions and diseases of the past millennium having been achieved in most developed countries, and with the resultant increase in life expectancies, much more attention seems to have shifted to degenerative health problems. Many of the degenerative health conditions have been linked to thousands of chemicals regularly encountered in human living and occupational/work environments. It is important, therefore, that human health risk assessments are undertaken on a consistent basis - in order to determine the potential impacts of the target chemicals on public health. This book provides a concise, yet comprehensive overview of the many facets/aspects relating to human health risk assessments in relation to chemical exposure problems. It presents some very important tools and methodologies that can be used to address chemical exposure and public health risk management problems in a consistent, efficient, and cost?effective way. Overall the book represents a collection and synthesis of the principal elements of the risk assessment process that pertain to human exposures to chemicals in the human living and work environments. It offers an understanding of the scientific basis of risk assessment and its applications to public health policy decisions. Audience: The subject matter of this book should be of interest to many a professional encountering risk assessment in relation to environmental contamination and public health risk management programs &e especially public and occupational health practitioners; environmental consultants; environmental attorneys; public policy analysts; and various health, environmental, and consumer advocacy interest groups. The book is also expected to serve as a useful educational and training resource for both students and professionals in the health-related and environmental fields &e who have to deal with human exposures to chemicals, public health risk assessment issues, and/or environmental health management problems.

Table of Contents

Preface	xiii
Acknowledgements	xv
Introduction	1	(18)
Coming to Terms with the Several Chemicals in Modern Society	2	(5)
The Nature of Chemical Hazards and Human Response from Exposure to Chemical Substances	7	(8)
Classification of Chemical Toxicity	8	(1)
Factors Influencing Chemical Toxicity to Humans and Human Response to Chemical Toxicants	9	(1)
Distribution and Storage of Toxicants in the Human Body	10	(1)
Scope of Chemical Hazard Problems: Lead Exposures as an Example	11	(4)
`The Dose Makes the Poison' -- So, What Dose is Safe Enough?	15	(1)
Managing the Chemical Exposure Problem: The Need for Public Health Risk Assessment	16	(2)
Suggested Further Reading	18	(1)
Human Exposure To Chemicals	19	(24)
An Overview of Human Contact Sites and Target Organs Most Susceptible to Chemical Exposures	19	(6)
Fundamentals of Human Physiology	20	(4)
Target Organ Toxicity	24	(1)
General Types of Human Exposures	25	(4)
The Nature of Chemical Exposure Problems	29	(5)
Human Exposures to Airborne Chemical Toxicants	30	(1)
Water Pollution Problems and Human Exposures to Chemicals in Water	31	(1)
Contaminated Soil Problems and Human Exposures to Chemicals on Land	32	(1)
Human Exposures to Chemicals in Foods	33	(1)
Public Health and Socio-Economic Implications of Chemical Exposure Problems	34	(6)
The General Nature of Human Health Effects from Chemical Exposures	38	(2)
Assessing Public Health Risks	40	(1)
Suggested Further Reading	41	(2)
Principles and Concepts in Risk Assessment	43	(28)
Fundamental Principles of Chemical Hazard, Exposure, and Risk Assessments	43	(8)
The Nature of Chemical Hazard, Exposure, and Risk	44	(2)
Basis for Measuring Risks	46	(2)
What is Risk Assessment?	48	(1)
The Nature of Risk Assessments	49	(1)
Recognition of Uncertainty as an Integral Component of Risk Assessments	50	(1)
Fundamental Concepts in Risk Assessment Practice	51	(4)
Qualitative versus Quantitative Risk Assessments	51	(1)
Conservatisms in Risk Assessments	52	(1)
Individual versus Group Risks	53	(1)
Consideration of Risk Perception Issues	54	(1)
Risk Acceptability and Risk Tolerance Criteria	55	(2)
The de Minimis or `Acceptable' Risk	56	(1)
General Attributes of Risk Assessment	57	(4)
The Purpose	58	(1)
The Attributes	59	(1)
Risk Assessment versus Risk Management	60	(1)
Risk Assessment as a Diagnostic Tool	61	(7)
Baseline Risk Assessments	62	(1)
Comparative Risk Assessments	62	(2)
Public Health Risk Assessments	64	(3)
Risk Assessment Implementation Strategy	67	(1)
Risk Assessment as an Holistic Tool for Environmental and Public Health Management	68	(1)
Suggested Further Reading	69	(2)
Principal Elements of a Public Health Risk Assessment For Chemical Exposure Problems	71	(16)
Characterization of Chemical Exposure Problems	71	(2)
Factors Affecting Exposure Characterization	72	(1)
The Risk Assessment Process	73	(4)
Hazard Identification and Accounting	74	(1)
Exposure-Response Evaluation	75	(1)
Exposure Assessment and Analysis	76	(1)
Risk Characterization and Consequence Determination	76	(1)
General Considerations in Public Health Risk Assessments	77	(6)
Determining Exposure-related Health Effects	78	(1)
Evaluating Factors that Influence Adverse Health Outcome	79	(4)
Human Health Risk Assessment in Practice	83	(3)
Suggested Further Reading	86	(1)
Chemical Hazard Determination	87	(18)
Chemical Hazard Identification: Sources of Chemical Hazards	87	(1)
Data Collection and Evaluation Considerations	88	(4)
Data Collection and Analysis Strategies	89	(1)
Reporting of `Censored' Laboratory Data	90	(2)
Statistical Evaluation of Chemical Sampling Data	92	(7)
Parametric versus Nonparametric Statistics	93	(2)
Statistical Evaluation of `Non-detect' Values	95	(1)
Selection of Statistical Averaging Techniques	95	(4)
Estimating Chemical Exposure Point Concentrations from Limited Data	99	(3)
Determination of the Level of Chemical Hazard	102	(1)
Suggested Further Reading	103	(2)
Exposure Assessment: Analysis Of Human Intake of Chemicals	105	(32)
Fundamental Concepts and Requirements in the Human Exposure Assessment Process	105	(6)
Factors Affecting Human Exposure to Chemical Hazards	106	(1)
Development of Human Exposure Scenarios	106	(2)
Chemical Intake versus Dose	108	(1)
Chronic versus Subchronic Exposures	109	(1)
Incorporating Chemical Bioavailability Adjustments into Exposure Calculations	109	(1)
Chemical Transformation Products in Risk Assessment: Incorporating Chemical Degradation into Exposure Calculations	110	(1)
Human Exposure Quantification: The Exposure Estimation Model	111	(11)
Potential Receptor Inhalation Exposures	113	(3)
Potential Receptor Ingestion Exposures	116	(5)
Potential Receptor Dermal Exposures	121	(1)
Establishing `Exposure Intake Factors' for Use in the Computation of Chemical Intakes and Doses	122	(10)
Illustrative Example for Inhalation Exposures	123	(5)
Illustrative Example for Ingestion Exposures	128	(1)
Illustrative Example for Dermal Exposures	129	(3)
Receptor Age Adjustments to Human Exposure Factors	132	(1)
Spatial and Temporal Averaging of Chemical Exposure Estimates	132	(3)
Suggested Further Reading	135	(2)
Evaluation of Chemical Toxicity	137	(36)
Fundamental Concepts and Principles in Toxicology	137	(7)
Mechanisms of Toxicity	138	(1)
Categorization of Human Toxic Effects from Chemical Exposures: Carcinogenicity vs. Non-carcinogenicity	138	(2)
Manifestations of Toxicity	140	(1)
Dose-Response Relationships	141	(3)
Carcinogen Classification Systems	144	(5)
Weight-of-Evidence Classification	145	(3)
Strength-of-Evidence Classification	148	(1)
Evaluation of Chemical Toxicity	149	(6)
Hazard Effects Assessment	150	(2)
Dose-Response Assessment and Quantification	152	(3)
Determination of Toxicological Parameters for Human Health Risk Assessments	155	(16)
Toxicity Parameters for Non-carcinogenic Effects	155	(6)
Toxicity Parameters for Carcinogenic Effects	161	(4)
The Use of Surrogate Toxicity Parameters	165	(6)
Mechanisms of Action and the Determination of Human Health Hazard Effects	171	(1)
Suggested Further Reading	172	(1)
Chemical Risk Characterization And Uncertainty Analyses	173	(40)
Fundamental Issues and Considerations Affecting the Risk Characterization Process	173	(10)
Corrections for `Non-Standard' Population Groups	174	(2)
Adjustments for Chemical Absorption: Administered vs. Absorbed Dose	176	(1)
Aggregate Effects of Chemical Mixtures and Multiple Exposures	177	(2)
Fundamental Considerations in the Health Assessment of Carcinogens	179	(4)
Carcinogenic Risk Effects: Estimation of Carcinogenic Risks to Human Health	183	(5)
Population Excess Cancer Burden	184	(2)
Carcinogenic Risk Computations: Illustration of the Processes for Calculating Carcinogenic Risks	186	(2)
Non-cancer Risk Effects: Estimation of Non-carcinogenic Hazards to Human Health	188	(5)
Chronic versus Subchronic Non-carcinogenic Effects	190	(1)
Non-carcinogenic Hazard Computations: Illustration of the Processes for Calculating Non-carcinogenic Hazards	191	(2)
Risk Presentation	193	(8)
Graphical Presentation of the Risk Summary Information	196	(5)
Uncertainty and Variability Issues in Risk Assessment	201	(5)
Types and Nature of Variability	201	(1)
Types and Nature of Uncertainty	202	(1)
Common Sources of Uncertainty in Public Health Endangerment Assessments	203	(3)
The Need for Uncertainty and Variability Analyses	206	(1)
Characterization of Data Variability and Uncertainties	206	(5)
Qualitative Analysis of Uncertainties	207	(1)
Quantitative Analysis of Uncertainties	208	(3)
Presenting and Managing Uncertain Risks: The Role of Sensitivity Analyses	211	(1)
Suggested Further Reading	212	(1)
Determination Of `Acceptable' And `Safe' Levels Of Chemical Exposure	213	(24)
Requirements and Criteria for Establishing Risk-Based Chemical Exposure Levels	213	(4)
Miscellaneous Methods for Establishing Environmental Quality Goals	214	(3)
Assessing the Safety of Chemicals in Consumer Products	217	(1)
Determination of `Tolerable' Chemical Concentrations	217	(1)
Determination of Risk-Based Chemical Exposure Levels	218	(6)
RBCELs for Carcinogenic Constituents	219	(3)
RBCELs for Non-carcinogenic Effects of Chemical Constituents	222	(2)
Establishing Risk-Based Cleanup Limits for Contaminated Lands	224	(5)
Soil Chemical Limits for Carcinogenic Contaminants	226	(1)
Soil Chemical Limits for the Non-carcinogenic Effects of Site Contaminants	227	(2)
Establishing Risk-Based Cleanup Limits for Contaminated Waters	229	(3)
Water Chemical Limits for Carcinogenic Contaminants	229	(2)
Water Chemical Limits for the Non-carcinogenic Effects of Site Contaminants	231	(1)
A `Preferable' Health-Protective Chemical Level	232	(3)
The Modified RBCEL for Carcinogenic Chemicals	232	(1)
The Modified RBCEL for Non-carcinogenic Constituents	233	(1)
Incorporating Degradation Rates into the Estimation of Environmental Quality Criteria	234	(1)
Public Health Goals vs. Risk-Based Chemical Exposure Levels	235	(1)
Suggested Further Reading	235	(2)
Design Of Public Health Risk Management Programs	237	(20)
Risk Assessment as a Cost-Effective Tool in the Formulation of Public Health and Environmental Management Decisions	237	(2)
Comparative Risk Analysis: Application of Environmental Decision Analysis Methods to Public Health Risk Management Programs	239	(6)
Cost-Effectiveness Analysis	240	(1)
Risk-Cost-Benefit Optimization	240	(1)
Multi-attribute Decision Analysis and Utility Theory Applications	241	(4)
The General Nature of Risk Management Programs	245	(2)
A Framework for Risk Management Programs	247	(2)
Risk Communication as a Facilitator of Risk Management	249	(2)
Designing an Effectual Risk Communication Program	250	(1)
The Use of Contemporary Risk Mapping Tools: GIS in Public Health Risk Management Applications	251	(4)
Utilization of GIS in Risk Assessment and Environmental Management Programs	252	(3)
The Role of GIS Applications in Environmental Management	255	(1)
Suggested Further Reading	255	(2)
The Role Of Risk Assessment In Public Health Policy Decisions	257	(18)
General Scope of Public Health Risk Assessment Practice	257	(7)
Illustrative Examples of Public Health Risk Assessment in Practice	258	(6)
The Public Health Risk Assessment Paradigm	264	(8)
Suggested Further Reading	272	(3)
List of References And Bibliography	275	(22)
Appendix A: Glossary of Selected Terms and Definitions	297	(28)
Appendix B: Selected Tools, Chemical Exposure Models, and Chemical Databases for Public Health Risk Policy Decision-Making	325	(12)
Appendix C: Toxicity Index Parameters for Selected Chemicals	337	(4)
Appendix D: Selected Units of Measurements & Noteworthy Expressions	341	(4)
Index	345