Bees and Pesticides: 70% Contamination in Massachusetts

Pesticides are in most pollen and honey samples collected from foraging bees in Massachusetts, researchers from Harvard T.H. Chan School of Public Health said recently in learnings published in the Journal of Environmental Chemistry.

That is, more than 70 percent of the samples contained at least one neonicotinoid, a class of pesticides that has been implicated in Colony Collapse Disorder (CCD). In CCD, adult bees abandon their hives during winter.

"Data from this study clearly demonstrated the ubiquity of neonicotinoids in pollen and honey samples that bees are exposed to during the seasons when they are actively foraging across Massachusetts. Levels of neonicotinoids that we found in this study fall into ranges that could lead to detrimental health effects in bees, including CCD," said Chensheng (Alex) Lu, an associate professor at Harvard Chan School and lead author of the study, in a release.

The significant losses of honey bee colonies since 2006 have scientists, policymakers, and others concerned because bees pollinate roughly one-third of crops worldwide.

Researchers analyzed pollen samples collected over time, during spring and summer when bees are busy foraging, from the same set of hives across the state of Massachusetts. In this way, scientists were able to find variations in the levels of eight neonicotinoids and determine high-risk locations or months for exposure for bees, the release said.

All in all, they looked at 219 pollen and 53 honey samples from 62 hives, from 10 out of 14 counties in the state. In each location and month, neonicotinoids were found, suggesting that bees are at risk of the pesticide exposure any time they forage anywhere in Massachusetts, according to the release.

Imidacloprid and dinotefuran were the most commonly detected neonicotinoids, the release noted.

The pesticides that seem to be pervasive throughout the state pose a risk for the survival of honey bees, as well as a health risk for humans inhaling neonicotinoid-contaminated pollen, Lu said, in the release. "The data presented in this study should serve as a basis for public policy that aims to reduce neonicotinoid exposure," he said.

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