Risk Assessment and Communication After Children’S Exposure to Environmental Toxicants

RISK ASSESSMENT AND COMMUNICATION AFTER CHILDREN’S EXPOSURE TO ENVIRONMENTAL TOXICANTS Erica L. Liebelt MD FACMT FAAP Department of Pediatrics and Emergency Medicine University of Alabama School of Medicine Children’s Hospital; Birmingham, AL A Project of the American College of Medical Toxicology funded by a cooperative agreement with the U.S. Agency for Toxic Substances and Disease Registry Medical Toxicologist Department of Pediatrics; Children’s Hospital Department of Emergency Medicine University of Alabama School of Medicine 1600 7th Avenue South, Midtown Center, Suite 205 Birmingham, AL 35233 Phone: 205-939-9587 Fax: 205-975-4623 Email: [email protected] 2 TABLE OF CONTENTS EXECUTIVE SUMMARY PART I RISK ASSESSMENT I. Taking an Exposure History II. Risk Assessment Process A. General Principles About Risk Assessment B. Step 1 - Hazard Identification C. Step 2 -Exposure Assessment 1. General Information 2. Special Considerations of Exposure Assessments in Children 3. External Exposure Monitoring in Children D. Step 3 -Toxicity Assessment 1. General Information 2. Special Considerations in Assessing Toxicity Due to the Biologic Environment of Children 3. Children’s Special Susceptibilities to Cancer in Risk Assessment E. Risk Characterization 1. General Information 2. Uncertainties and Weaknesses of the Risk Assessment Process 3. Reconceiving Risk Characterization III. New Approaches to Risk Assessment in Children A. Modifying the Risk Assessment Process for Children B. Using Biologic Markers in the Pediatric Risk Assessment Process IV. National Initiatives to Improve the Risk Assessment Process in Children V. Information Resources for the Risk Assessment Process and Pediatric Environmental Health VI. References Part II – RISK COMMUNICATION I. Introduction II. Background and Definition of Risk Communication III. What is Risk? A. Risk Acceptability and Risk Perception IV. The Process of Risk Communication A. General Principles About Risk Communication 1. Basic Communication Strategies 2. Risk Communication Problems 3. Cardinal Rules of Risk Communication B. Explaining Risk 1. General Principles 2. Risk Messages – Informing and Influencing 3. Communicating Technical Information 4. Explaining Uncertainty 3 5. Guidelines for Appropriate Use of Risk Comparisons C. Trust and Credibility D. Successful Risk Communication V. Information Resources for Risk Communication – Publications and Internet sites VI. References SUMMARY 4 EXECUTIVE SUMMARY Environmental toxicants are a persistent and increasing cause of preventable diseases in children. Childhood exposures are also known and suspected to be associated with adult-onset diseases. With technological advancements in our society, the number and variety of chemicals to which humans are exposed have increased significantly in the last 20 years. Children are exposed to a diverse number of environmental toxicants at home, school, play, and daycare settings as well as indirectly through their parents’/guardians’ occupational and environmental exposures. There are over 80,000 chemicals in commercial use today in the United States with hundreds of new chemicals being developed and released into the environment every year. In addition, children are at risk for exposure to nearly 15,000 high-production-volume synthetic chemicals, most of which have been developed in the past 50 years.95 Thus, the extent of children’s exposures to potentially toxic substances will undoubtedly continue to increase. Many of these materials are contained in household products and dispersed widely in the environment.26 A significant proportion of chemicals have never been tested for their potential toxicity, and thus potential dangers to children are unknown. 54, 116 Since the toxic effects of most of these chemicals, particularly long-term effects, are largely unknown, it is difficult to assess and communicate accurate concerns to health care providers and the public. Historical incidents demonstrating environmental poisoning of children provide the scientific foundation for further research into the relationship between environmental exposure and disease. Chemicals including PCBs (polychlorinated biphenyls), hexachlorobenzene, lead, and organic mercury have caused exaggerated toxicity in children compared to adults, illustrating the vulnerability and unique susceptibility of children. Unique exposure patterns, immaturities in physiological development, and different target organ susceptibilities as well as dependence on others to separate them from potentially harmful exposures make infants and children an especially vulnerable segment of population that requires special attention. Children’s environmental health issues are clearly an important health priority for the new millenium. Effects of environmental toxicants on children are a growing concern. It has been estimated that over a million children less 5 than the age of 6 live within one mile of toxic waste sites on the National Priority List. (The National Priority List is the Environmental Protection Agency’s listings of the most seriously contaminated hazardous waste sites in the country in need of cleanup because of their threat to human health and the environment. ) From a public health standpoint, what are the potential short- and longterm effects of these chemicals on developing children? Recent research has suggested that one of every 200 children in the United States now suffers from a developmental or neurological disability which was caused by an environmental toxicant.122 As a result of increasing awareness and publicity of environmental threats to children, pediatric health care providers (PHCPs) will need to be able to address questions and concerns from a child’s caretaker/parents as well as the local daycare and school. Parents may have specific requests for concrete information such as “What chemicals in our well water can be harmful to my children?”, “ or “What lead level will be harmful to my child?”. Other questions may be more difficult to answer; for example, “What is the chance my child will develop cancer from the contaminants found in our garden soil?” , “Is my child’s learning disability due to the carbon monoxide leak from our faulty furnace system?” or “What long-term effects might my child encounter from exposure to low levels of radon in the basement?”. It is of utmost importance for pediatricians and other pediatric health care providers to educate themselves and their colleagues about these issues which are threatening America’s 70 million children. General pediatric textbooks have little detailed information on environmental illness while original research and specific topics on these issues are dispersed throughout the literature and internet in sources not traditionally read or accessed by pediatric health care providers. Medical schools are estimated to provided no more than four to six hours of instruction in environmental and occupational health. Until the recent change in pediatric residency curriculum requirements and some teaching about lead poisoning, pediatric training programs were generally not teaching about children’s environmental health. The American Academy of Pediatrics recently published a Handbook of Pediatric Environmental Health which provides an excellent overview and concise summaries of environmental hazards to children, as well as practical information to be used in the office setting on diagnosing, 6 treating, and preventing childhood diseases associated with environmental exposures.41 However, once an environmental exposure has occurred or is suspected to have occurred, there is a need to provide an accurate assessment of the exposure and determine the risk of potential harmful effects for the child, if any. Furthermore, it is important to be able to communicate information to parents and the public about potentially hazardous environmental exposures in an accurate, ethical, and practical manner. The objective of this monograph is to discuss the processes of risk assessment and risk communication as they apply to children’s exposures to potentially toxic substances in the environment. The terms “children” and “child” refer to infants, children, and adolescents except where specific differences are noted. First, the basics of taking an exposure history will be reviewed in association with brief discussions of particular environmental toxicants that the pediatric health care provider should be familiar with. Next, the traditional components of quantitative risk assessment (QRA) will be outlined, discussing in detail these analyses and their limitations. Special characteristics of the pediatric population that need to be considered in assessing exposure and toxicity will also be discussed. Unique susceptibilities of children to cancer as they relate to environmental toxic exposures will be reviewed as well as the role of biological markers in pediatric risk assessment. New approaches to risk assessment in children will be proposed. National initiatives that include the pediatric population in the risk assessment process will be addressed. Finally, selected information resources that might be helpful in understanding risk assessment and the various analyses will be reviewed. The second section of the monograph will focus on the process and components of successful risk communication in relation to pediatric environmental health exposures. Specifically, it will discuss the multidimensional definition of risk and qualitative factors affecting people’s perception and acceptability of risk—

Load more