Pitt researchers find toxic metals move from soil to flowers, affecting bumblebees

A University of Pittsburgh study links toxic amounts of aluminum and nickel found in flowers to health problems in bumblebees.

Bumblebees risk ingesting toxic amounts of the metals in flowers growing in soil that was contaminated by exhaust from vehicles, industrial machinery and farm equipment, according to the study, which was published in Environmental Pollution, a research journal.

“Folks are just starting to look at how metal accumulation affects plants and insects that pollinate,” said George Meindl, co-author of the study and doctoral candidate in biology at Pitt.

The Pitt study found bumblebees can taste yet ignore metals such as nickel.

“Although many metals are required by living organisms in small amounts, they can be toxic to both plants and animals when found in moderate to high concentrations,” said Tia-Lynn Ashman, principal investigator of the study and professor and associate chair in Pitt's department of biological sciences. “These metals can interfere with insect taste perception, agility and working memory — all necessary attributes for busy bumblebee workers.”

Bees didn't sense aluminum, Meindl said.

Unlike honeybees, bumblebees are mostly natural pollinators. While the Pitt study involved bumblebees, Meindl said the heavy metals likely harm honeybees.

He said the research does not prove a connection between heavy metals and colony collapse disorder, a syndrome that has resulted in commercial beekeepers losing at least 30 percent of their bees each winter since 2006.

Researchers say CCD is caused by a mix of factors.

Beekeeper Brett Adee, whose Adee Honey Farms in Bruce, S.D., is the nation's largest, doubts that heavy metals play a role in the syndrome.

“That might be a concern in real industrial areas. Bees were kept exceptionally healthy for decades and there have been heavy metals around for years — probably more in the past than now. I don't think a change that was so fast, like CCD, could have been primarily caused by heavy metals,” said Adee, who lost 55 percent of his 70,000 bee colonies during the winter.

Rick Wills is a staff writer for Trib Total Media. He can be reached at 412-320-7944 or rwills@tribweb.com.