Controversial pesticides found in honey samples from six continents

James Marshall
Октября 5, 2017

In three years they amassed 198 samples from every continent except Antarctica, and tested them for neonicotinoids.

She said: "The discovery of bee-harming pesticides in honey samples across Europe reinforces the need for a complete and permanent ban on these chemicals". This information could help governments worldwide weigh the risks and benefits of using neonicotinoids and help scientists trace their path into the honey we consume.

The first global honey survey testing for these controversial nicotine-derived pesticides shows just how widely honeybees are exposed to the chemicals, which have been shown to affect the health of bees and other insects. Almost half of the samples tested contained levels of neonicotinoids at least as high as those thought, on the basis of previous research, to impair bees' brain function and slow the growth of their colonies.

The presence of pesticides varied regionally - 86 percent of the North American samples contained at least one of the five commonly used neonicotinoids that the study measured, while only 57 percent of South American ones did. "Anybody could have guessed that", says lead author Edward Mitchell, a biologist at the University of Neuchâtel in Switzerland. "We now have a worldwide map of the situation". Some studies have suggested that exposure to neonicotinoids lowers honey bees' nutritional status and impairs their immunity.

"The fact that 45 ideal of our samples showed multiple contaminations is worrying and indicated that bee populations throughout the world are exposed to a cocktail of neonicotinoids", the paper states. These levels are below the highest concentrations of pesticide residue allowed for food or feed by the European Union (EU), but could have dire consequences for the world's declining bee population.

The extent of the contamination, even in honey from remote places - including islands in the middle of the Pacific Ocean and off the coast of West Africa - is surprising, says Amro Zayed, an insect researcher at York University, UK.

Alexander Aebi, a scientist from University of Neuchâtel who took part in the study, says this research confirmed his team's fears: that the majority of their samples were contaminated by at least one molecule. "I was also shocked to see that there is no region in the world that is not exposed to neonicotinoids".

Now it is illegal to use the pesticides thiamethoxam, clothianidin and imidacloprid, on mass-flowering crops that attract bees. Some chemicals can boost each others' toxic effects over time, says Connolly.

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