Are Children More Vulnerable to Environmental Chemicals?

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Edited by Daland R. Juberg, Ph.D.

Foreword by former U.S. Surgeon General Dr. C. Everett Koop

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Executive Summary

Public concern about environmental health threats to children has intensified in recent years and has caused scientists, politicians, regulators, and public health officials to take notice. The issue is whether young children, infants, and fetuses are at an increased health risk from environmental chemicals, either because they have a heightened susceptibility to such compounds, and/or because they have higher relative exposures to environmental chemicals than do adults. From a public health perspective, this is a legitimate question. And because both as a society and as individuals, we place great value on providing a safe environment for children, it is important to determine whether this concern is scientifically valid.

Protecting children from environmental chemicals has become the singular focus for many advocates who believe that children are at a greater risk from environmental exposures and that strict regulatory action must occur. We are at a juncture where emotion, fear, and uncertainty compete with scientific data, toxicological principles, and principles of risk analysis. Because this is an important public health question, the American Council on Science and Health (ACSH) has evaluated this topic from several critical perspectives.

From an exclusively scientific perspective, Part I of this comprehensive assessment concludes that for the vast majority of substances that are commonly referred to as "environmental chemicals" there is not enough supportive scientific evidence to suggest that children are uniquely susceptible. Further, Part I reveals the following:

People have a fear of the unknown and unfamiliar, which includes chemicals and the hazards they might pose. As a result, public perceptions of child susceptibility to chemicals are heavily influenced by psychological factors rather than dispassionate assessments of actual health risk.

There is little toxicological evidence to support the premise that children are consistently more susceptible to environmental chemicals than adults. Increased child susceptibility has been shown for a few specific chemicals, and in these cases measures should be taken to proactively protect children from exposure to such compounds. Based on data from laboratory animals and from an understanding of pharmacological action in humans, however, children may be either more or less susceptible to the potential health effects of chemicals, depending on the specific chemical and the level and timing of exposure.

There are few empirical data to support the claim that children have greater exposure to environmental chemicals than adults. This is because their exposure, with few exceptions, has not been systematically measured. While children may have greater contact than adults with some aspects of the environment, the reverse is also likely for other aspects. In addition, toxicologists now recognize that the bioavailable dose of chemicals (amount of metabolized chemical that the body actually absorbs) may be a more relevant indicator of potential health risk than is simple exposure. Such data are currently limited for both children and adults and should be further collected.

Chemical contamination of the environment in the U.S. has declined over the past 20 years due to decreased inputs, regulatory initiatives, and pollution prevention efforts. As a result, chemical concentrations in the environment, such as in air, water, and soil, and in aquatic and wildlife species are generally declining as well. As a result of this cleaner environment, levels of certain persistent chemicals in humans have also decreased, including lower blood lead levels (in children and adults) and decreasing PCB (polychlorinated biphenyls) and DDT (dichlorodiphenyl trichloroethane) concentrations in human breast milk. Thus, concern over child susceptibility is increasing at a time when ecosystem health is improving and human exposure to environmental chemicals is declining.

Some claim that childhood diseases and disorders such as asthma, intellectual deficits, and cancer are associated with "environmental factors," which is a broad term. Environmental factors include lifestyle, such as diet and exercise, as well as biological, physical, and chemical agents all of which may influence childhood development. Despite the common perception that "environmental factors" is synonymous with "environmental synthetic chemicals," there is limited empirical evidence for an etiological role for such chemicals in childhood diseases.

Concern for children's susceptibility to chemical hazards has focused primarily on a few specific chemicals or chemical groups such as lead, PCBs, and pesticides. For lead, there is a recognized physiological basis for children's increased susceptibility; however, for PCBs and pesticides, a similar basis is not known to exist. For other commonly cited potential hazards such as phthalates, there is no consistent evidence of human harm, including for children.

The possible risks to children's health from endocrine modulating substances ("endocrine disrupters") found in the environment have generated considerable scientific debate and media attention. These substances, at high concentrations, have been associated with adverse or toxic effects in certain wildlife species. While some people have also tried to link endocrine modulators to negative human health outcomes, such as cancer in hormonally sensitive tissues, declining sperm counts in men, and disruption of the normal course of sexual development in young girls and boys, the weight of scientific evidence does not support these claims.

Parents frequently assume voluntary risks for their children (excessive sun exposure, contact sports, bicycle riding without helmets) but are less tolerant of perceived involuntary risks (environmental chemical exposure), despite the fact that the former often represent greater risks to a child's health. While failing to put children's risk in perspective is common, it is vital to help children, parents, and policymakers distinguish between known and hypothetical risks.

From advocacy and regulatory perspectives, Part II of this review explains how activist groups use alleged risks from chemicals and other environmental fears to manipulate parents' very legitimate and appropriate concerns for their children's health. Most often, these campaigns are an effort to promote legislation, regulation, and litigation that is based not in science, but rather in a political agenda opposed to technology, free markets, and scientific progress. Part II illustrates how children have become victims of these crusades. Further, Part II discloses the following:

Children have been portrayed as victims by anti-chemical campaigns throughout history. This originated out of real concerns such as those about the milk supply but developed into hypothetical risks from Coca-Cola and pesticides. By examining such instances in the past, one can see how activists' use of children as pawns evolved and has escalated in recent decades, as their campaigns have become more sophisticated.

The media play a decisive role in disseminating well-orchestrated scare campaigns focusing on children's exposure to man-made chemicals or to products containing them. In a highly competitive business, the media serve as gatekeepers of health information, and reports of children's risks gain significant and vital audience attention.

The U.S. government plays a significant role in the campaign against chemical use, with children's health serving as an important vehicle. The U.S. Environmental Protection Agency (EPA) has aggressively contributed to the campaign, with some assistance from other federal agencies. The EPA's most significant accomplishment to date is to institutionalize special concern for potential threats to children's health from man-made chemicals in the environment.

As with so many other public health false alarms, the attack on the new biotechnology also known as bioengineering, gene splicing, or genetic engineering is less about real concern for children's health than about environmental activists' willingness to exploit children's issues for their own agenda.

Environmental chemicals are only one type of hazard that children and infants may face. However, environmental chemicals often pale in comparison to other children's health risks, such as automobile and bicycle accidents, sports injuries, drowning, and accidental poisoning. Understanding and giving proper attention to real children's health risks, versus those risks that are hyped into fears, is critical so that environmental chemical risks can be seen in the proper perspective and children's health can be maintained.

The belief that children are consistently at increased risk from environmental chemicals is too widely cast and not supported by scientific evidence. There are cases in which certain children may be more susceptible than adults to an environmental hazard. However, the same could be said for people of any age depending on the health status of the individual, the specific agent in question, and the exposure scenario. Discussions of child susceptibility should be focused on specific agents under specific exposure scenarios, including in utero exposures, and should bring all of the scientific evidence to bear on an assessment of risk. Based on existing data and multidisciplinary scientific evaluation, there is little basis for the belief that an impending crisis looms with respect to children's health from environmental chemicals. In order to achieve sound public health policies, we must evaluate environmental health issues based on scientific standards, not ill-conceived but well-coordinated efforts to substitute emotional currency for established scientific criteria. Understanding the underlying agendas of activist and regulatory groups further clarifies the misleading information often given to the public. Doing so will ensure that children's environmental health issues are properly prioritized within the larger perspective of overall childhood risks.

Table of Contents
Children's Health: A Cause for Concern
C. Everett Koop, M.D., Sc.D.

Executive Summary

Part I:
A Scientific Assessment of Children's Susceptibility to Environmental Agents

Daland R. Juberg, Ph.D.

Chapter 1
The Role of Anxiety and Fear in Perceptions of Risk and Vulnerability
Elissa P. Benedek, M.D. and Beth K. Clark, Ph.D.

Chapter 2
Toxicology and Children's Health
Michael A. Kamrin, Ph.D.

Chapter 3
Exposure Assessment an Important Component of Health Risk
Daland R. Juberg, Ph.D.

Chapter 4
Current Trends in the Study of Ecosystem Health and Contaminants in the Environment
Daland R. Juberg, Ph.D.

Chapter 5
Facts and Myths About Childhood Ailments and Diseases Frequently Linked to Environmental Exposures: Cancer, Asthma, Intelligence Deficits, Attention Deficit Hyperactivity Disorder, Autism
Miles M. Weinberger, M.D.

Chapter 6
Examples of Alleged Chemical Threats to Children: Lead, Pesticides, PCBs, "Endocrine Disruptors," Phthlates
Daland R. Juberg, Ph.D.

Chapter 7
The Latest Example of Alleged Chemical Threats: Endocrine Modulators
Ruth Kava, Ph.D., R.D. and Daland Juberg, Ph.D.

Chapter 8
Putting Children's Risks from Chemicals into Perspective
Kimberly M. Thompson, Sc.D.

Part II:
Advocacy and Regulatory Issues

Ashlee Dunston

Chapter 9
From Real Dangers to Phantom Risks: Historical Perspective on Environmental Threats to Children's Health
Ronald Bailey

Chapter 10
The Role of the Media
Bonner R. Cohen, Ph.D.

Chapter 11
The Role of the Government
Steven J. Milloy

Chapter 12
Children, Fear, and Biotechnology
Henry Miller, M.D. and Gregory Conko

Chapter 13
Real Risks Vs. Hyped Fears: Priorities in Caring for Your Children
Kristine Napier, M.P.H., R.D.

Parting Thoughts