Lead Contamination in the Drinking Water of Pompeii

Duncan Keenan-Jones, John Hellstrom and Russell Drysdale

Was poisoning from lead pipes a risk for the people of ancient Pompeii? The question of lead poisoning in Roman water systems has been a matter of debate for some time (Kobert 1909; Gilfillan 1965; Waldron 1973, 392-393; Hodge 1981; Scarborough 1984, 475). The current consensus holds that a layer of calcium carbonate called sinter developed on the inside of lead pipes, protecting the drinking water from lead contamination. A study of ninety-two skeletons from Herculaneum, however, shows exceptionally high levels of lead concentrations in a contemporary and nearby population believed to have been supplied by the same aqueduct. These concentrations are higher even than modern workers who endured longterm exposure to lead (appendix 1). There were, however, several possible sources of lead poisoning in ancient Pompeii other than the lead pipe water supply. Our research has shown that very high levels of lead are found within the sinter deposits themselves at varying locations along the water distribution system within Pompeii. These facts bring into question the commonly held belief that sinter build up prevented lead contamination in Roman drinking water.

Therefore, the present study examines the issue of lead contamination in Pompeii’s water supply by attempting answer to two related questions. First, was sinter build up an effective protection against the absorption of lead in the water supply? Second, what was the source of the lead found in sinter deposits in Pompeii? To answer each of these questions, the potential sources of lead contamination must be isolated. The paper therefore begins with a discussion of the aqueduct systems that might have served Pompeii and their sources (parent water), as well as consideration of environmental contaminants and the city’s water distribution system itself. The second half of the paper details the results of our study of eighteen samples of sinter using a method called laser ablation inductively coupled plasma mass spectrometry in order to determine whether lead concentrations changed as the sinter deposits grew over time. To our knowledge, this is the first time such a method has been employed. Detailed discussion of the sampling strategy (appendix 2) and methodology (appendix 3) are found at the end of the paper.