NADD - An association for persons with developmental disabilities and mental health needs

From the NADD Bulletin Volume XI Number 6

Precautionary Principle - Supporting a Healthy Environment for All

Steven G. Gilbert, PhD, DABT, Institute of Neurotoxicology & Neurological Disorders

Introduction

"A thing is right when it tends to preserve the integrity, stability, and beauty

of the biotic community. It is wrong when it tends otherwise."

Aldo Leopold, 1949, A Sand County Almanac

Our interaction with the environment begins at conception and continues throughout our lives. A profound change occurred along with the chemical revolution, we are now exposed to a wide range and mixture of manufactured chemicals and environmental contaminates that we know cause learning and developmental disorders as well as other diseases (Gilbert, 2007b; Schettler, Stein, Reich, Valenti & Wallinga, 2000). The challenge is to reduce our exposure to these hazardous agents to ensure that all people can reach and maintain their full potential.

While we know from scientific research and tragic experience that exposure to some chemicals clearly causes learning and developmental disorders, for the vast majority of chemicals we have little knowledge of potential developmental effects. Figure 1 graphically depicts that of the approximately 80,000 registered chemicals we know very little about the potential hazards of the majority. The Toxics Substance Control Act (TSCA) passed in 1976 to give the Environmental Protection Agency (EPA) authority to regulate and request toxicity data from the chemical industry has largely failed adequately to provide information to protect the public. In contrast there is a very different and precautionary approach to regulating the safety and testing of medical drugs. The US Congress granted the Food and Drug Administration (FDA) authority to require information and data on both the efficacy (does it work) and safety (what are the side effects) of new drugs. The pharmaceutical and biotechnology industries are required to test their potential products prior to release to sale to the public. They do this research at their expense because they are the ones expected to make money from the product. We have adopted a very precautionary approach to drug development and human exposure.

Figure 1. What we do and don't know about chemicals that cause developmental disorders can harm us (from Gilbert, 2007).

The problem of not having sufficient information about the potential hazards of a chemical is compounded by not knowing what chemicals are in the products and thus we don't know what we might be exposed to. In the last year well known hazardous materials such as lead were found in baby toys. A very recent study has brought attention to a wide range of hazards in common products such as air fresheners (Steinemann, 2008). From conception onward throughout our lives we are exposed to a wide array of environmental contaminates and manufactured chemicals.

The challenge is to adopt a decision-making approach grounded in science but which also incorporates philosophical and ethical components that sufficiently value human and environmental health. The precautionary principle, initially developed in Europe, incorporates both a scientific and values-based approach as foundations to decision making.

Precautionary Principle and Ethics

"When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically."

Wingspread Statement, 1998

The unique strength of the precautionary principle is that it combines an ethical perspective while being grounded in science. Many of the public health and child health issues that we must confront are in large part a matter of applying existing knowledge to inform a policy-based decision. Garrett Hardin (1968) points out that many of the problems that we face, or that we have created, have no technical solutions but must be managed. For example, more research on child health is not required to make the policy-based decision to invest in reducing childhood lead exposure so that no child has a blood levels above 2 µg/dL(Gilbert & Weiss, 2006). Our decision making must be guided by our values and ethical considerations. Children have a right to develop in an environment in which they can reach and maintain their full potential(Gilbert, 2005a; Weiss, 2001). This right implies that we have a duty, an ethical responsibility, to protect the most vulnerable of our society. When we distribute lead, mercury, PCBDs or PCBs into the environment, or put them in consumer products, we are not only exposing our children to compounds that rob them of their potential we are also harming the much broader biotic community. While protecting our children, we must also acknowledge a responsibility to wildlife and the greater biotic community.

Most importantly, the precautionary principle implies that we need to take action to promote or protect public health even when there are uncertainties. The burden of responsibility to demonstrate safety is shifted to the proponents of an activity or use of a chemical. Currently the burden of demonstrating harm from exposure is borne by the public and our government agencies. Thus we spend millions of dollars over decades for research to demonstrate the harmful effects of low level lead exposure. Industries that used lead and facilitated its spread across the environment were not required to demonstrate safety or even required to help with the ongoing studies of potential hazards. The profits were privatized while our children and the environment bore the costs. Corporations have repeatedly been allowed to external costs while not accounting for the true costs to society, human health or the environment. Thousands of new chemicals are introduced into commerce each year with only minimal knowledge of their potential effects on human health or environmental consequences, which puts society in the position of proving harm after exposure. The five basic elements of the precautionary principle can be summarized as:

·Set public health goals.

·Taking preventive action in the face of uncertainty.

·Shifting the burden of responsibility (proof) of safety to the proponents of an activity.

·Exploring a wide range of alternatives to possibly harmful actions.

·Increasing public participation in decision making. (Gilbert, 2005b; Montague, 2008).

Public participation can be increased by modifying the classical risk assessment approach. Risk assessment is a process which evaluates the potential exposures and hazards of chemicals or activities to make a judgment on a likelihood of harm. There are many criticisms of risk assessment but one of the best was by stated by William Ruckelshaus (1st administrator of U.S. EPA) in 1984, "We should remember that risk assessment data can be like the captured spy: If you torture it long enough, it will tell you anything you want to know." Risk assessment is often characterized as a four step process. 1) Hazard identification - using structure activity relationship, cell culture, animal studies or human studies to characterize the hazard. 2) Exposure assessment - evaluates the type and means of exposure as well who or what might be exposed. 3) Dose / response assessment - determines appropriate end points or response and mathematically characterize the dose / response relationship, which usually means extrapolation to the lowest doses that might produce a response. 4) Risk characterization - brings all this information together to characterize the risk. The process is generally driven by experts that are forced to use the data they have, not the data they need, to make a determination of the most sensitive health effects.

An alternative approach is precautionary assessment (Gilbert, 2006). The goal of precautionary assessment (PA) is to move beyond risk assessment and allow communities and individual to incorporate their knowledge, values, and ethics into a more comprehensive evaluation of a hazardous condition. Precautionary assessment combines the philosophy and ethics of the precautionary principle with the standard scientific evaluation of the hazard and exposure. PA is built upon a belief that we have the knowledge and also a duty to prevent disease and promote human and environmental health. Precautionary assessment contains three basic elements: a) community and social issues, b) exposure issues, and c) hazard and toxicity issues. Each element is broken down into a series of questions that are scored numerically and summed to produce a summary score for each element. A lack of knowledge usually is indicated by applying the highest score. The PA is designed to help place the knowledge available within the context of the community. The PA allows a community to prepare an alternative to the classical risk assessment, pose questions, and seek additional information.

Health Effects of Chemicals

"Given the established knowledge, protecting children from neurotoxic environmental exposures from the earliest stages of fetal development through adolescence is clearly an essential public health measure if we are to help reduce the growing numbers of those with learning and developmental disorders and create an environment in which children can reach and maintain their full potential." (LDDI Scientific Consensus Statement on Neurodevelopmental Disorders [Gilbert, 2007])

There is an established consensus that a range of environmental contaminates and other chemicals can cause neurodevelopmental disorders (Gilbert, 2007). Early exposure to environmental contaminants such as lead, mercury, pesticides, alcohol, and others are associated with neurodevelopmental disorders, such as learning disabilities, autism spectrum disorder, attention deficit hyperactivity disorder (ADHD), intellectual disabilities, and developmental delays. There is also increased concern about a broad class of chemicals called endocrine disruptors such as phthalates and bisphenol-A (BPA) that can also influence development.

Children are more sensitive to chemical exposures than adults for several reasons. Most importantly many cells are dividing and changing during development. Billions of cells in the nervous system are forming new connections essential for learning and memory. Environmental contaminates can damage this process and cause disabilities or poor performance that last a life time. Immature organs can also respond differently. For example, children absorb about 50% of the lead they ingest while adults only absorb 10%. This is because lead substitutes for calcium and children need more calcium for their growing bodies. It is very important to recognize that children are not little adults.

The incidence of learning and developmental disabilities appears to be rising, affecting between five and 15 percent of all children under the age of 18 in the United States, or more than 12 million children under 18. In general, disabilities have increased significantly over the past four decades. This has led to increased costs and lost opportunities for society (Landrigan, Schechter, Lipton, Fahs, & Schwartz, 2002). The costs to society are conservatively estimated to be in the billions of dollars per year just from childhood exposure to environmental contaminants. Great attention must be paid to the true costs of an exposure to environmental contaminants. When this is done the return on investment in ending exposure pays enormous dividends to society and the individuals.

Policy Initiatives - Taking Action

Acknowledging that environmental contaminates cause learning and development disorders and acknowledging our ethical duty to protect the most vulnerable requires us to take action to protect the children of our society. Action can take many forms and include making personal efforts to adopt more healthy habits, conducting additional research, enacting regulatory changes to protect health, or working to educate the public about the health effects of chemicals. Recent state and national regulations have been passed to limit the amount of lead, cadmium, and phthalates in children's products after experiencing tainted products. A more fundamental change would be for the CDC to lower the childhood blood lead action level from 10 to 2 µg/dL (Hardin, 1968). The National Children's Study (n.d.) is just getting started to track a large number of children across the country to assess exposures and health outcomes. Comprehensive chemical policy reform is an essential action, which includes amending the Toxic Substances Control Act (TSCA). A policy statement (Gilbert, 2008) was derived from and accompanies the Scientific Consensus Statement on Environmental Agents Associated with Neurodevelopmental Disorders was signed by many leading scientists and public health professionals. "The goal of the policy statement is to help scientists, medical professionals, policymakers, public health advocates and the general public address the important issues raised by preventable environmental exposures that may contribute to learning and developmental disabilities." Education is also a critical factor. The world wide web offers many new opportunities to share and make information available. Blogs, social networking sites and wiki sites such as Toxipedia (www.toxiepdia.org) are just the beginning of the digital revolution.

Conclusion

To forge a more healthy and peaceful world we must unite the sciences with our values to emphasize the common interests we all share. The precautionary principle can serve as a guide to decision making that helps unite science and ethics. It provides a framework for engaging the community in the decision-making process. We have the knowledge and the resources to enact polices that are protective of public health and the environment. Our challenge is to look toward future generations as we work together for a sustainable environment in which all creatures can reach and maintain their full potential.

References

Gilbert, S.G. (lead author) (2008). Policy implications based on the scientific consensus statement on environmental agents associated with neurodevelopmental disorders. Developed by the Collaborative on Health and the Environment's Learning and Developmental Disabilities Initiative. (Available online at: http://www.iceh.org/pdfs/LDDI/LDDIPolicyStatement.pdf).

Gilbert, S.G. (lead author) (2007). Scientific consensus statement on environmental agents associated with neurodevelopmental disorders. Developed by the Collaborative on Health and the Environment's Learning and Developmental Disabilities Initiative. (Available online at: http://www.iceh.org/pdfs/LDDI/LDDIStatement.pdf.)

Gilbert, S.G. (2006). 'Precautionary assessment' - A new tool for making decisions. Rachel's Precaution Reporter #65. "Foresight and Precaution in the News and in the World." . http://www.precaution.org/lib/06/ht061122.htm (Environmental Research Foundation http://rachel.org/).

Gilbert, S.G. (2005a). Ethical, legal, and social issues: Our children's future. Neurotoxicology, 26, 521-530.

Gilbert, S.G. (2005b). Public health and the precautionary principle. Northwest Public Health.

Gilbert, S.G. & Weiss, B. (2006). A rationale for lowering the blood lead action level from 10 to 2 microg/dL. Neurotoxicology, 27, 693-701.

Hardin, G. (1968). The tragedy of the commons. The population has no technical solution; it requires a fundamental extension in morality. Science, 162, 1243-8.

Landrigan, P.J., Schechter, C.B., Lipton, J.M., Fahs, M.C., & Schwartz, J. (2002). Environmental pollutants and disease in American children: Estimates of morbidity, mortality, and costs for lead poisoning, asthma, cancer, and developmental disabilities. Environmental Health Perspective, 110(7) 721-8.

Montague, P.X. (2008). The precautionary principle in the real world. Environmental Research Foundation. http://www.precaution.org/lib/pp_def.htm .

National Children's Study (n.d.). http://www.nationalchildrensstudy.gov/.

Schettler, T., Stein, J., Reich, F., Valenti, M., & Wallinga, D. (2000). In harm's way: Toxic threats to child development. Cambridge, MA: Greater Boston Physicians for Social Responsibility.

Steinemann, A.C. (2008). Fragranced consumer consumer products and undisclosed ingredients. Environmental Impact Assessment Review.

Weiss, B. (2001). Ethics assesment as an adjunct to risk assessment in the evaluation of developmental neurotoxicants. Environmental Health Perspectives, 106 (Supp 6), 905-8.

For further information, contact Dr. Gilbert at sgilbert@innd.org.

The NADD Environmental Health Project, funded by the John Merck Fund, provides professionals, families, and the general public with relevant information concerning toxic agents and their affects on neuro-development. For further information visit www.thenadd.org and click on "Environmental Health Project," or contact Ed Seliger, Project Coordinator, at eseliger@thenadd.org.