INTRODUCTION
Lead poisoning is currently thought to be one of the most serious diseases of environmental and occupational origin because of its high prevalence, environmental pervasiveness, and persistence of toxicity in affected populations. Lead poisoning affects virtually all human biochemical processes and organ systems, and it can lead to a broad range of serious and often irreversible sequelae in reproduction and effects in the cardiovascular, hematopoetic, and central nervous systems. Of special concern is lead's impact on children, whose nervous systems are particularly sensitive. Among the most deleterious neuropsychological effects of lead poisoning on the very young are learning and reading disabilities, reduced psychometric intelligence, and childhood behavioral disorders. All of these have been recognized over time to occur at progressively lower levels of exposure, and all may be predictive of serious behavioral and other disorders later in life. Although more is known about the health effects and exposure pathways of lead than most other environmental contaminants, the global dimensions of the problem remain poorly understood and documented.
Yet, lead poisoning is also an entirely preventable disease. Cost-effective technical and nontechnical measures to reduce sources of exposure are available. Because it is difficult and costly to control lead once it is released—and because medical treatment does not fully reverse health effects—the most useful strategies of disease prevention are directed toward controlling lead at its primary sources, for example, through engineering measures in the workplace or replacement of lead with safer substances. There are a number of improved practices that can reduce exposures in cases where lead cannot be replaced. These practices include education and training, surveillance of exposures and health effects, and, in occupational settings, use of personal protective equipment for workers exposed to lead.
In most countries of the world, however, the technical means and knowledge required to recognize and reduce environmental and occupa-
tional exposures to lead do not exist. National policymakers are thus seriously disadvantaged in their ability to make adequate assessments and appropriate decisions about public health investments and allocations of human and financial resources. As a result, opportunities to incorporate primary prevention of environmental diseases into economic and social development programs may be missed. Assistance organizations at all levels, including international development and technical assistance agencies, local nongovernmental organizations (NGOs), and community-based environmental action groups have similar, corresponding difficulties. Recognizing this, in 1993 the Board on International Health of the Institute of Medicine proposed an international symposium and associated workshops on the topic of lead and health. The objectives of the activity were twofold: to provide a forum for the exchange of current information on major sources and toxic effects of lead exposure and to offer a neutral venue for North and Latin American and Caribbean policymakers, private sector representatives, research scientists, community representatives, and health professionals to identify cost-effective strategies for reducing lead exposures in the hemisphere. The symposium was to: (1) review and assess what is known about the magnitude of lead toxicity as a public health problem in selected countries of the Americas; (2) review and assess what is known about the sources of lead in the Americas, levels in various environmental media, and the uses of lead that increase human exposure; (3) evaluate transnational impacts of lead, including environmental fate and transport, and transboundary movements of lead in commerce, including recycling and waste disposal; and (4) develop a framework for the identification, analysis, and articulation of integrated control strategies to reduce environmental and occupational exposures to lead and consequent human disease. The conference was designed to build on the solid evidentiary base provided, in part, by past efforts of the National Academy of Sciences (NRC, 1980, 1993) and other influential bodies (Alliance to End Childhood Lead Poisoning and EDF, 1994; ATSDR, 1988; CDC, 1991; National Center for Lead-Safe Housing, 1995; OECD, 1994).
The Board decided to focus on lead exposure reduction in the Americas for four general reasons:
One, many countries in North and Latin America and the Caribbean are beginning to respond to environmental concerns and are looking for guidance in the allocation of funds for environmental research and intervention. The region has already seen agreements between the public and private sectors with respect to reducing environmental lead.
Two, the growing liberalization of U.S. trade with Mexico and the other Latin American countries—and the environmental challenges this presents, both with respect to the environment and to the transborder movement of goods and wastes—requires timely development of acceptable, consistent, and cost-effective strategies for preventing diseases in the region.
Three, the close cultural similarities among countries in the region will increase the likelihood that lead poisoning prevention strategies successful in one region of the Americas will provide a useful framework for public health policy elsewhere in the hemisphere. Examination of the successful dialogue between the public and private sectors in Mexico in reformatting ceramic glazes, for example, may offer a model for comparable successful strategies in other countries of the Americas.
Four, this project builds on a growing portfolio of IOM activities, conducted in collaboration with institutions in Mexico and Canada, that focus generally on review of transfers of knowledge of health risks and benefits related to the economic, social, and cultural integration of Mexico, the United States, and Canada that is occurring as a result of accelerating trade liberalization. This growing partnership was deepened by the decision of the IOM and the National Institute of Public Health of Mexico to collaborate in hosting the conference, which was ultimately held at the National Institute of Public Health's main campus in Cuernavaca, Morelos, Mexico.
The advisory committee of 11 members from Latin America, the Caribbean, and North America was chosen to oversee the planning and implementation of the symposium and workshops. The committee had a broad range of expertise in international health, public health, health policy, toxicology, environmental and occupational epidemiology, environmental engineering, economics, and community-based intervention strategies for environmental risk reduction.
The committee met first in November 1994 in Washington, D.C., to plan the agenda for the symposium and workshops. The subsequent conference was held over a three-day period, 8-10 May 1995. Days 1 and 2 of the symposium each began with a plenary session featuring presentations on the health effects and treatment of lead toxicity, the prevalence and severity of lead toxicity in the hemisphere and issues of data quality, and major sources and pathways of lead exposure. There were also four case studies of lead exposure interventions highlighting examples of voluntary industry initiatives and the roles of the federal sector, international organized labor, and community activism and education in promoting
reduced exposure levels. In addition to the 10 plenary presentations, 28 posters presenting data on various aspects of lead and health in the Americas were on display throughout the conference. Afternoons featured six working group sessions on the following topics: gasoline; paint; ceramicware glazes; industrial and occupational health; food, water, and waste disposal; and techniques for improved lead surveillance and monitoring. Each session was responsible for identifying specific action steps that could be tailored by participants to regional, federal, or local needs, as required, to reduce human lead exposure across the Americas. The final plenary session on Day 3 featured the presentations of the working groups and identification of action steps that were common across all six groups. The conference also offered a workshop on Analytic Methods for Blood Lead Measurements sponsored by the U.S. Centers for Disease Control and Prevention (CDC).
This report of the conference, which is being published in both English and Spanish versions, contains four chapters and six appendixes. Chapter 1 summarizes the findings, conclusions, and recommendations of the symposium participants for the prevention of lead poisoning in the Americas. Chapter 2 describes the history of public health concerns about lead poisoning and the voluntary and regulatory steps taken to date to reduce human lead exposures. Chapter 3 provides summaries of the plenary session presentations, and Chapter 4 summarizes the findings of the six working groups. The report also features six appendixes: Appendix A provides a list of references cited; Appendix B offers descriptions of the poster presentations; Appendix C summarizes the workshop on Analytic Methods presented by the CDC; Appendix D offers brief descriptions of federal and private organizations involved in lead poisoning prevention activities in the hemisphere and provides contact information for readers interested in obtaining further information; Appendix E offers the conference agenda; and Appendix F the list of conference attendees with contact information for each.
The committee recognizes that the strategies for recognizing and eliminating lead poisoning agreed upon by the symposium participants are based predominantly on the successful experiences of the United States, Europe, and those of the Finnish Lead Program in the developing world as reported Dr. Jorma Rantanen, the keynote speaker. It was the consensus of participants, however, that these successful experiences are both relevant and applicable to prevention and control of lead poisoning in the Americas. The committee also recognizes that the general set of prevention and control strategies identified by symposium participants will need to be adapted, at least in part, for and by specific countries. It will have to take into account
differences in cultures and politics, levels of technological development and economic resilience, predominant sources of lead, and the distribution of exposures. Also, in every country, individuals from a variety of disciplines, working at different levels in the public and private sectors, will need to be substantively involved in the tailoring and implementation of these action steps. Regional, country, and local policymakers should include in their decisionmaking the broad range of interested, and affected, parties, including health care providers and representatives of community-based environmental action groups. In particular, it is important to involve leaders in industries and businesses that use or produce lead in their merchandise or as a by-product of manufacturing or use. It was the consensus of conference attendees that the building of such broadbased coalitions is crucial to the acceptance and success of actions to reduce environmental and occupational lead exposures across the countries of the Americas.
