OSU scientists use honey to trace heavy metal contamination

Scientists from Canada and the United States are using honey from neighborhood beekeepers to test for the presence of heavy metal pollution – a new application of a technique that uses isotope analysis to search for low levels of lead, zinc, copper and other elements.

The study is thought to be the first of its kind in North America using honey as a biomonitor. It was led by researchers at the University of British Columbia, including Kate Smith, who is the first author and a Ph.D. student, and Oregon State University.

Results of the research were published last week in Nature Sustainability.

“Urban geochemistry is an emerging field, but because it focuses on concentrated population centers, it can be very complicated,” said Alyssa Shiel, an Oregon State geochemist and co-author on the study. “You have to factor in the local infrastructure – including roads, industrial areas and residential areas – as well as historical land use.

“But the positive thing is the study shows that we not only can identify low levels of heavy metals; we also can use the ‘isotopic fingerprints’ to give us a strong idea as to where they came from.”

The study focused on beehives in six neighborhoods in Vancouver, British Columbia. The researchers say honey collected from local hives provides a good indication of nearby conditions because honeybees typically utilize pollen and nectar within a range of 1-2 miles.

The researchers carried out their study using sophisticated instruments that measure the elements in parts per billion, said UBC’s Dominique Weis, project lead PI. It is the “equivalent of one drop of water in an Olympic-size swimming pool.”

The researchers found traces of lead in the honey, but those isotopic fingerprints did not match any local, naturally occurring lead sources, suggesting a fairly clean local environment. However, some of the honey – as well as trees they tested in Vancouver’s Stanley Park – revealed isotopic fingerprints with some lead that was chemically similar to aerosols, ores and coal from large Asian cities.

The good news is that it was in small enough amounts that it shouldn’t be a human health concern, the researchers noted. It would take consumption of about two cups of honey per day to exceed tolerable levels.

“This is a great example of how citizen science can play a role in helping researchers address issues around the world,” Shiel said. “Urban beekeeping is on the rise, and honey is an untapped resource that can be used as a biomonitor.”

Shiel is on the faculty of Oregon State’s College of Earth, Ocean, and Atmospheric Sciences.