A recent study has found that over 75% of honeys sampled worldwide contained pesticides that are harmful to bees. The pesticides found are known as neonicotinoids and have been shown to reduce cognitive functioning in bees, which many believe is the major cause of bee die-offs in recent years.
The study, published in the journal Science, sampled honeys from around the world and found that the concentration of pesticides was highest in North America (86%). The next highest levels were found in Asia (80%) and Europe (79%), with the lowest levels measured in South America (57%).
The study shows that we are not able to control the spread of pesticides as easily as we think, says Mark Winston, a bee researcher with Simon Fraser University.
“We used to think that neonicotinoids are only found in areas where they are heavily used on one particular crop,” Winston told the CBC, “but this study is consistent with others that have found neonicotinoids up to quite a few kilometres away from the place where they are used,” Winston said.
As plant pollinators, bees are vital to ecosystems and to human food production. But a nationwide American survey of beekeepers found that they lost 44% of colonies in 2015-2016.
In response, some cities and countries are moving to ban the pesticides that are believed to be contributing to the problem. The EU instituted a temporary three-year ban on using neonicotinoids on some crops in 2013, and a full ban has since been proposed. In Canada, neonicotinoids are fully banned in the cities of Montreal and Vancouver.
The pesticides found in the honey are not generally considered harmful to humans, although Winston says he tries to avoid eating foods containing lots of pesticides. He also says that it’s important to look at the issue holistically, as neonicotinoids can make bees more vulnerable to other pesticides.
“We really have to be looking at what happens when we put them all together,” he said.