Lead

Sources of Exposure to Lead

There are three primary avenues of exposure to lead: (1) environmental sources that are more or less shared by all persons in a given population; (2) occupational exposures from manufacturing or handling lead and lead products; and (3) pediatric exposures, due to the special environmental, behavioral, and metabolic features of early childhood.

Until a few decades ago, people living in industrialized nations routinely faced lead levels higher than those in industrial settings where lead was used, as a result of exposure via air pollution, water supply systems, adulterated foods, medicines, and other sources. Assays of historical lead pollution show a steady increase in bioavailable lead in the general environment from early-modern times, accelerating dramatically in the middle of the 20th century with increased consumption of leaded gasoline. In addition to such airborne sources, lead made its way into foods via insecticide residues and pigments and into drinking water via solid-lead or lead-soldered water supply pipes. Lead-tainted alcohol is implicated in widespread chronic illness from the 18th century through the early 20th century, and alcohol distilled illegally in lead-soldered automotive radiators (e.g., ‘moonshine’) continues to produce occasional outbreaks of saturnism.

At the beginning of the 20th century, the health burden of these universal exposures remained largely hidden beneath the crushing mortality and morbidity from lead in the workplace. From 1910 to 1930, federal mortality statistics reported more than a hundred lead-poisoning deaths annually. But these reports drastically underreported lead-poisoning cases; Leake, a New York physician, complained in 1927 that ‘there are many plants… from which no lead cases are reported, except those failing to ‘get by’ the coroner’ (Leake, 1927). In the Progressive Era (ca. 1890– 1913), the fatal conditions in America's lead factories prompted a number of government-sponsored investigations, such as those conducted by Alice Hamilton. The resulting social and political pressure, together with a constricting labor market and the adoption of workers’ compensation laws, prompted manufacturers to adopt basic improvements in ventilation and processes. Workers’ compensation laws also transformed factory culture, as an empowered force of industrial hygienists sought to control the physical and fiscal costs of occupational sickness. Together, these factors dramatically lowered American workers’ exposure to bioavailable lead.

It took considerably longer to fully assess and respond to the ubiquitous dangers lead posed children. Young children in urban and suburban environments were exposed to most of the ‘universal’ sources adults faced, prompting one astute pediatrician, Ruddock, in 1924 to alert his peers that ‘the child lives in a lead world.’

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