Teeth reveal hard lives of medieval lead mining communities

Part of medieval Derbyshire may have had worse pollution than during the Industrial Revolution - and women may have suffered the most, archaeologists have found.

The Peak District was a centre for lead production in the Roman period but details of it restarting after the imperial era were unclear.

Analysis of lead deposits in teeth from burials in the area indicate rising levels of contamination as mining restarted in the mid 7th Century, reaching a peak in the 13th Century, at levels which outstrip those from the Victorian era.

On top of this, female skeletons showed higher lead levels and an earlier age of death, which may be linked to re-exposure during pregnancy, researchers said.

Lead was a major product of Roman Britain, used in water pipes, wine vessels, cosmetics and roofing, but the industry seems to have slumped as imperial administration failed.

While it was known the Derbyshire industry had become a major player in medieval Europe, it was not clear when it began to recover - nor the impact on the local environment.

Answering this question had been hampered by the practice of reworking Roman and medieval mines and resmelting the lead waste in the 16th to 19th Centuries, researchers said.

Now, a team led by the University of Nottingham has used a novel source of information - analysis of pollution in tooth enamel - to identify when the mines reopened.

Tooth enamel forms during childhood, giving a durable record of the environmental chemicals absorbed during these early years.

Christopher Loveluck, professor of Medieval European Archaeology at the University of Nottingham, said: "What we were measuring was the lead concentrations incorporated into the teeth when the individuals were children.

"So that incorporation could have happened either from a lead contaminated environment or it could have happened as a result of children actually helping process lead, which basically means smash it up into smaller pieces for smelting.

"And it showed the levels were off the scale".

Dating the graves showed lead production restarted in the mid 7th Century but did not affect everyone equally.

Loveluck said: "We found particularly men who had been accompanied with ostentatious weapons, they had very low levels of contamination, whereas individuals who didn't have any grave goods in the early to mid 7th century often had higher levels of contamination.

"Interestingly, women had higher levels of contamination too, which would suggest that a lot of the wealthier adult men may have been administering lead mining and smelting but that a lot of less wealthy children, including girls, may have been more involved in sort of crushing ore after it had been mined out.

"Additionally, the females studied seemed to have died younger - between 17 and 25 - and these graves were close to those of younger children, which may indicate the lead absorbed during childhood had a serious impact during pregnancy."

Dr Anna Bloxam, co-director of the Castleton excavations, said: "We know from modern studies that lead can have profoundly harmful effects on the health and development of children - there is no safe level of exposure.

"All the individuals included in our study survived into adulthood, but they were exposed to lead while they were young and growing.

"We can tell from their skeletons that most of the men we studied lived until middle or old age, whereas the women primarily died much earlier, in young adulthood."

Lead contamination levels rose as the industry expanded, but what surprised researchers were the concentrations found.

Loveluck said: "By 1200, everybody's contaminated at levels, really, which are higher than those of the Industrial Revolution between 1750 and 1900.

"What that really tells us is that some of our notions about the Industrial Revolution specialisation and pollution do not seem to be correct - there wasn't a linear increase in contamination as industry expanded.

"In certain industries, there is a much bigger impact on the environment earlier on and that's certainly the case in the Peak District."

Such was the extent of the contamination that Alpine ice cores and sediment cores from European river channels, lakes and peat bogs have identified a particular rise in atmospheric lead pollution, which is attributed to British production around 1200.

Bloxam said: "Our results indicate that in these mining communities, girls and boys alike were raised in dangerously polluted home environments.

"This exposure will likely have caused negative health effects in life, and perhaps contributed to higher rates of premature death among women of child-bearing age."

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