WASHINGTON — When researchers collected honey samples from around the world, they found that three-quarters of them had a common type of pesticide suspected of playing a role in the decline of bees. Even honey from the island paradise of Tahiti had the chemical.
That demonstrates how pervasive a problem the much-debated pesticide is for honeybees, said authors of a study published Thursday in the journal Science. They said it is not a health problem for people because levels were far below governments’ thresholds on what’s safe to eat.
‘‘What this shows is the magnitude of the contamination,’’ said study lead author Edward Mitchell, a biology professor at the University of Neuchatel in Switzerland, adding that there are ‘‘relatively few places where we did not find any.’’
Over the past few years, several studies linked insecticides called neonicotinoids or neonics, to reduced and weakened honeybee hives, although pesticide makers dispute those studies. Neonics work by attacking an insect’s central nervous system.
Bees and other pollinators have been on the decline for more than a decade and experts blame a combination of factors: neonics, parasites, disease, climate change, and lack of a diverse food supply. Honeybees don’t just make honey; about one-third of the human diet comes from plants that are pollinated by the insects. Bees pick up the pesticide when they feed on fields grown from treated seeds.
The Swiss researchers asked other experts, friends, and relatives to ship honey samples. More than 300 samples arrived and researchers tested 198 for the most common types of neonics.