More than 70% of pollen and honey samples collected from foraging bees in Massachusetts contain at least one neonicotinoid, a class of pesticide that has been implicated in Colony Collapse Disorder (CCD), in which adult bees abandon their hives during winter, according to a new study by Center faculty member Alex Lu, associate professor of environmental exposure biology at Harvard T.H. Chan School of Public Health.
“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 Dr. Lu, associate professor of environmental exposure biology in the Department of Environmental Health at Harvard Chan School and lead author of the study.
Since 2006, there have been significant losses of honey bee colonies. Scientists, policymakers, farmers, and beekeepers are concerned with this problem because bees are prime pollinators of roughly one-third of all crops worldwide.
Previous studies analyzed either stored pollen collected from hives or pollen samples collected from bees at a single point in time. In this study, the Harvard Chan School researchers looked at pollen samples collected over time—during spring and summer months when bees forage—from the same set of hives across Massachusetts. Collecting pollen samples in this way enabled the researchers to determine variations in the levels of eight neonicotinoids and to identify high-risk locations or months for neonicotinoid exposure for bees. To do so, the researchers worked with 62 Massachusetts beekeepers who volunteered to collect monthly samples of pollen and honey from foraging bees, from April through August 2013, using pollen traps on the landings of beehives. The beekeepers then sent the samples to the researchers.
The researchers analyzed 219 pollen and 53 honey samples from 62 hives, from 10 out of 14 counties in Massachusetts. They found neonicotinoids in pollen and honey for each month collected, in each location—suggesting that bees are at risk of neonicotinoid exposure any time they are foraging anywhere in Massachusetts.
The most commonly detected neonicotinoid was imidacloprid, followed by dinotefuran. Particularly high concentrations of neonicotinoids were found in Worcester County in April, in Hampshire County in May, in Suffolk County in July, and in Essex County in June, suggesting that, in these counties, certain months pose significant risks to bees.
The new findings suggest that neonicotinoids are being used throughout Massachusetts. Not only do these pesticides pose a significant risk for the survival of honey bees, but they also may pose health risks for people inhaling neonicotinoid-contaminated pollen, Lu said.
The data presented in this study should serve as a basis for public policy that aims to reduce neonicotinoid exposure.
Other Harvard Chan School authors of the study included doctoral student Chi-Hsuan Chang, research fellow Lin Tao, and research associate Mei Chen.
Funding for this study came from the Woodshouse Foundation and the Harvard-NIEHS Center for Environmental Health (P30ES000002).
The results of a study conducted by Harvard T.H. Chan School of Public Health indicate that over 70% of pollen and honey samples collected from foraging bees in Massachusetts contain at least one neonicotinoid pesticide, which is linked to Colony Collapse Disorder (CCD). CCD is a phenomenon in which adult bees abandon their hives during winter, leading to significant losses of honey bee colonies since 2006. Bees are prime pollinators of about one-third of all crops globally, making their survival critical. The study found that neonicotinoids were present in pollen and honey samples collected from bees in every month and location sampled in Massachusetts, suggesting that bees are at risk of exposure whenever they are foraging anywhere in the state. The most commonly detected neonicotinoid was imidacloprid, followed by dinotefuran. The study calls for public policy that aims to reduce neonicotinoid exposure to address the significant risk posed to the survival of honey bees and the potential health risks posed to people who inhale neonicotinoid-contaminated pollen.
“Distributions of neonicotinoid insecticides in the Commonwealth of Massachusetts: a temporal and spatial variation analysis for pollen and honey samples,” Chensheng (Alex) Lu, Chi-Hsuan Chang, Lin Tao and Mei Chen, Journal of Environmental Chemistry, online July 23, 2015, doi: 10.1071/EN15064
