Want to know how polluted your city is? Just ask the bees

Aside from their essential role as polinators, new research shows the insects may have another role to play

Urban-dwelling bees not only can help measure a city's pollution levels, they also can help pinpoint its source, according to a new study from the University of British Columbia.

The secret: The bees' honey, and what levels of particular elements are in it.

The UBC researchers collected honey from beehives in six neighbourhoods across Metro Vancouver, tested it for levels of lead, copper and other elements, then carried out isotope analysis to find out where they came from.

“The instruments ... are very sensitive and measure these elements in parts per billion, or the equivalent of one drop of water in an Olympic-sized swimming pool,” Dominique Weis, the report's senior author and director of UBC's Pacific Centre for Isotopic and Geochemical Research (PCIGR), said in a release from UBC.

As it happened, the Vancouver bees' honey told a tale of a metropolis with "extremely clean" air, and the researchers' methods were precise enough that they could detect higher densities depending on how close they were to downtown Vancouver.

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For lead in particular, they found the traces detected in Vancouver bees' honey didn't seem to come from local sources, and when compared to lead samples taken from trees in Stanley Park, evidence suggested an origin far from the shores of B.C.

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“We found they both had fingerprints similar to aerosols, ores and coals from large Asian cities,” said Weis. “Given that more than 70 per cent of cargo ships entering the Port of Vancouver originate from Asian ports, it’s possible they are one source contributing to elevated lead levels in downtown Vancouver.”

The scientists joined forces with local non-profit Hives for Humanity, which promotes urban beekeeping, and they say it's the kind of thing that could help boost citizen science.

“One of the exciting parts of this study is that it bridges science with community interests,” Kate E. Smith, the lead author of the study, said. “Honey sampling can easily be performed by citizen scientists in other urban centres, even if they lack other environmental monitoring capabilities.”

The study was published earlier this month in Nature Sustainability

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