Franklin Expedition deaths likely caused by zinc deficiency, finds new study

Were the Franklin Expedition deaths caused by a zinc deficiency?

Scientists have drawn new conclusions as to the fate of the members of the ill-fated Franklin Expedition, all from analysis of a 170-year old thumbnail.

In a study published in the Journal of Archaeological Science: Reports, led by Dr. Jennie Christensen of Stantec and TrichAnalytics, the researchers, including scientists from the University of Saskatchewan were able to employ a synchrotron particle accelerator to analyze samples inside the sliver of nail from able seaman John Hartnell, whose body was discovered on Beechey Island where Franklin and crew spent the winter of 1845-46 after their two ships became ice-bound in September of 1845.

Previous analysis in the early 1980s of the bodily remains suggested that the cause of death might have been lead poisoning, attributed to the crewman’s consumption of preserves from cans with improperly applied lead sealant.

But the new results indicate otherwise: the nail tissue was found to contain high levels of lead, say the authors, but the crewman’s lead levels were found to have only spiked above normal during the last few weeks of his life, a sign of dramatic weight loss which can cause lead stores in the bones to leach into the bloodstream. The new study’s authors now believe that tuberculosis brought on by a prolonged zinc deficiency was the more likely cause of death.

“That zinc deficiency would explain that he had a very low immune function,” says Laurie Chan, study co-author from the University of Ottawa. “In the tough environment, he probably contracted infections and died from (tuberculosis).”

“The process of starvation from tuberculosis in Hartnell resulted in the exponential release of previously stored lead from his bones into the blood. Lead concentrations were only high and increasing at the end of his life when he was already likely near death. This explains why previous researchers discovered high lead concentrations in soft tissue; however, they erroneously concluded it was due to recent exposure,” says Christensen.

The nail fragment also told researchers that Hartnell did not consume much meat over his final days, a perplexing fact considering that both ships were well-stocked with meat preserves. “We see a clear decline of meat consumption,” said Chan. “If all the canned food (had lasted) he should not have that problem. It’s probably because some of the canned food was spoiled.”

The wrecks of two ships, the HMS Erebus and HMS Terror were recently discovered by search expeditions in 2014 and September of 2016, respectively. All of the 129 crewmen and officers of the expedition are suspected to have perished in the Arctic.

Other theories of the sailors’ demise have been offered.

One recent study by researchers at the University of Glasgow in Scotland argues that the cause of death for some of the crewmen and officers could have been accidents and injuries suffered during hunting expeditions, rather than illness or lead poisoning.

The authors contend that of the 24 men who had died by the time the crew abandoned their ice-bound ships in 1848, 15 were officers, a disproportionate number, which might indicate something other than illness at root. “It would be difficult to find a particular health factor that would suggest the crews were in any particular difficulty health-wise at the time of leaving the ships,” says Keith Millar, lead author of the study.

Scientists hope that with the use of advanced technology, more about the Franklin Expedition will come to light.

“New techniques, new scientific innovations, help us look into this in different ways,” said Joyce McBeth, assistant professor of geological sciences at the University of Saskatchewan and co-author of the new study. “These techniques were not used back in the ’80s, back when this was first done, so with new developments in science, we’re able to ask different questions than we asked previously.”

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