The hundreds of tons of lead that burned in the April 2019 fire and almost destroyed the Notre-Dame cathedral in Paris creates a dangerous dust that ended up in parks, buildings, and playgrounds and triggered health alarms. Now, say scientists, part of this lead has found its way to a surprising place: honey produced by urban beehives.
A study conducted this week in Environmental Science & Technology Letters found that honey collected from the fire northwest of the cathedral against the wind contained, on average, almost three times as much lead as before the fire.
As an investigator, continue to look for the origins of the fire that devastated the 850 year old cathedralScientists, architects and historians examine the fragile structure of the building and the rubble. Other research has focused on the pollution caused by the 460 tons of lead that were burned that night.
The honey study, conducted by Kate Smith and Dominique Weis from the University of British Columbia, is one of the first to study the relationship between fire pollution and the impact on residents through a product that they can take directly.
The lead concentration of the honey – an average of 2.3 nanograms per gram – was below consumption standards, said Ms. Smith, a doctoral student in geosciences and lead author of the study.
She said the higher lead levels corresponded to the geographic distribution of the cloud of dust carried by the fire over Paris.
“The evidence is fairly strong that the fire caused the lead increase seen in honey,” said Ms. Smith.
Urban beekeeping has grown rapidly in cities like Paris in the past decade, and the city has recently estimated that it has more than 1,000 beehives. Bees have settled on the roofs of the gilded Opera Garnier and in renowned restaurants, in the flowery Luxembourg Gardens and also in Notre-Dame, where 200,000 bees that lived on the roof survived the fire.
The study on the Parisian beehives related to 36 honey samples collected in July 2019, a few months after the fire. Pre-fire samples were used as a reference.
It was found that not only before the fire, but also afterwards, the honey collected from Notre-Dame’s wind contained three times as much lead as in samples collected elsewhere in central Paris. In a beehive, the values were almost nine times normal.
Ms. Smith said that while the levels measured in honey were safe, the Parisians were right to be concerned about alarming lead levels after the fire. “Lead is known for its toxicity,” said Ms. Smith. “The health risk is not reduced simply because the lead was not recently deposited.”
Ms. Smith’s research focuses on how bees can act as sensitive pollution detectors. When bees search for pollen or nectar, they pick up tiny particles of lead and other metals, and the honey they produce provides a snapshot of the immediate surroundings of their beehive.
Researchers remain concerned about the effects of Notre-Dame fire pollution.
In a study by Lead levels in Paris soil Columbia University scientists released earlier this month found that people living within 1,100 meters and facing the wind of fire were likely to experience more lead failures than previously announced.
Previous research on the French news website Media Part and later the New York Times found unsafe lead levels in dozens of places in Paris, including schools, parks, and daycare centers.
The city and state authorities only ordered lead tests one month after the fire. It took four months to completely decontaminate the neighborhood of the cathedral.
When ingested, lead can cause cognitive damage, especially in children. City officials have acknowledged that Paris needs a more comprehensive lead reduction plan, and scientists are investigating whether rainwater falling from the roof of Notre-Dame may have polluted the Seine for centuries.
Professor Weis, the study’s other lead author, was in Paris the day after the fire and said she was far from the cathedral for fear of exposure to lead. Although the lead levels measured in honey were “80 drops of water in an Olympic swimming pool”, they should still serve as a warning.
“It is not dramatically high for Paris and it does not mean that the honey cannot be eaten,” added Professor Weis about the lead levels. “But honey is the canary in the coal mine.”