Social and Economic Dimensions of Environmental Policy: Lead Poisoning as a Case Study

PERSPECTIVES IN BIOLOGY AND MEDICINE Volume 41 ¦ Number 3 ¦ Spring 1998 SOCIAL AND ECONOMIC DIMENSIONS OF ENVIRONMENTAL POLICY: LEAD POISONING AS A CASE STUDY DAVID C. BELLINGER and JULIA A. MATTHEWS* Part One Nearly three decades ago, the microbiologist Rene Dubos expressed his puzzlement over the persistent problem of lead poisoning, saying that, ' 'The problem is so well-defined, so neatly packaged, with both causes and cures known, that if we don't eliminate this social crime, our society deserves all the disasters that have been forecast for it" (cited in [I]). The scientific basis for regulatory action to reduce lead poisoning, especially childhood lead poisoning, is unusually broad and deep compared to that available for other environmental pollutants. Nevertheless, the pace of efforts in this century to reduce the substantial morbidity associated with this disease has been sluggish. This issue, then, affords an opportunity to examine why the availability of a large body of supporting scientific data does not necessarily lead to timely changes in public health policy. Dimensions of the problem other than those of a purely medical/ scientific nature are likely to have played an important role in the neglect of lead poisoning. Like all public health issues, it can best be understood by considering aspects of its historical context. While a reductionist, purely *Department ofNeurology, Children's Hospital, Harvard Medical School, and Department of Psychiatry, University of Massachusetts Medical Center. The authors acknowledge the helpful comments of Paul Mushak, Herbert L. Needleman, and James Sargent. Correspondence: Neuroepidemiology Unit, Children's Hospital, 300 Longwood Avenue, Boston, MA 02115.© 1998 by The University of Chicago. All rights reserved. 0031-5982/97/4004-1031$01.00 Perspectives in Biology and Medicine, 41, 3 ¦ Spring 1998 | 307 toxicological approach focuses narrowly on the adverse health effects of lead exposure, a more broadly focused "ecological" approach seeks to understand causal pathways at the societal level and, specifically, to identify the social forces and economic institutions that created and maintained widespread lead exposure, particularly among certain segments of the population [2, 3]. For instance, in a study of the distribution of childhood lead poisoning in Massachusetts towns, Bailey and colleagues found that rates were higher in towns with an industrial heritage, a greater proportion of older housing, female-headed households, and African-Americans [4]. They argued that their results demonstrated how past patterns of industrial and urban development shape the patterns of future disease. In this paper, several hypotheses will be offered about the ways in which consideration of this larger context may account for the saltatory nature of efforts to address "the lead problem." Some history is necessary in order to set the frame for this discussion. Because of lead's many useful properties, it has been mined for at least 5,000 years. A plot of the time course of global lead production reveals a steady increase, with major shifts reflecting technological advances and changes in geopolitical or economic conditions, such as the Industrial Revolution in the 18th century and the introduction of lead as a gasoline additive in the early 20th century [5]. Accordingly, human activity has been the most important factor in the global biogeochemical cycling of lead. Currently approximately 1 million tons per year are dispersed into the biosphere , with the total over the past 5 millennia reaching about 300 million tons [6] . Isolated environmental media (e.g., snow strata, tree rings, marine sediments) provide an historical record of lead deposition rate. The rate has accelerated over the course of the 20th century, even in areas far removed from industrial and urban sources. The implications of this can be appreciated by estimating what an average human blood lead level would be if the lead ore within the earth's crust had never been disturbed. Using a linear biokinetic model, Mushak estimated that the "natural" blood lead level of young children in the prehistoric/preindustrial era was in the range of 0.06 to 0.12 micrograms per deciliter of whole blood (referred to as µg/dL) [7]. Based on the relationship between the concentration of lead in blood and bone in contemporary humans and the known level of lead in skeletons of humans who lived in the...