Distribution and Incidence

The geographic distribution of lead poisoning is global, but it is not of equal frequency everywhere.

Because circumstances leading to lead exposure are of anthropogenic origin, the prevalence of plumbism correlates with practices and traditions of lead use. Predictably, the geographic pattern of such episodes has varied with time.

Although there are few recorded instances of major health problems due to lead in antiquity, some perspective on the extent of lead poisoning can be gained by reviewing lead production records. Figure VIII.77.1 represents an approximation calculated by C. C. Patterson and others. Because galena is the most abundant form of natural lead ore in Europe and Asia, and because its very low solubility produces little toxicity for its miners, one could reasonably surmise that lead poisoning probably was not common prior to the popularization of the smelting process about 3500 B.C.

The cupellation process, discovered about 3000 B.C., permitted the separation of the small amounts of the commonly "contaminating" silver from the much larger quantities of smelted lead, and was followed by a substantial increase in lead production as a by-product of the pursuit of silver in the Mediterranean area. We only speculate about the degree to which lead toxicity affected those involved in lead production in the Middle East and Mediterranean area during these periods, though the crude nature of the furnace facilities must have exposed many to a toxigenic degree.

Introduction of coinage during Greece's Classical Period resulted in a phenomenal increase in silver (and therefore, lead) production, which was exaggerated by Roman exploitation to the point of ore exhaustion, leading to a marked reduction of that form of mining after the decline of the Roman Empire. Reference to lead intoxication can be found in the various Greek and Roman writers of antiquity (details under History and Geography: Historical Antiquity). It was then not until the late Middle Ages that lead production rose again, this time in Europe, with recognition of lead's utility now justifying its acquisition for its own sake. Although the Spanish pursuit of silver in the New World was second only to that of gold, the miners' mortality was largely due to factors other than poisoning from lead in the ore, and heavy metal toxicity during the silver extraction process was related primarily to the mercury used after 1570. It was the Industrial Revolution, with its enormous surge in lead production, that was responsible for the recurrent endemics in France, Italy, Spain, Germany, and especially Great Britain, and later, their New World colonies. Even so, the 80,000 tons of lead generated annually worldwide at the apex of

Figure Vm.77.1. World lead production during past 5,500 years. [Adapted from Roger L. Boeckx. 1986. Report. Analytical Chemistry 58 (February): 275A, reprinted by permission from Analytical Chemistry, 1986, American Chemical Society.]

Discovery of cupellation

Introduction of coinage

Rise and fall of Athens A

Roman Republic and Empire

5500 5000 4500 4000 3500 3000 2500 2000 1500 1000

Corrected MC (solar) years before present

Discovery of cupellation

Introduction of coinage

Rise and fall of Athens A

Silver [ Industrial production »¡volution Exhaustion'" Germany of Roman Spanish production lead mines of silver in New World

Roman Republic and Empire

5500 5000 4500 4000 3500 3000 2500 2000 1500 1000

Corrected MC (solar) years before present

Roman productivity has expanded exponentially to reach more than 3 million tons worldwide today. With this exponential rise has come a staggering degree of lead exposure in the populations of Western nations.

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