"What we have found is a high degree of pollution", said Edward Mitchell, biology expert at the University of Neuschtel, Switzerland.
Concentrations found in 198 samples of honey from different parts of the world are not risky for humans - their effect is below the European Union norm. An updated assessment that is slated to appear in the journal Environmental Science and Pollution Research found even stronger evidence that the insecticides are harmful, and reportedly concludes: "The consequences are far reaching and can not be ignored any longer".
They found that three quarters of all the honey samples contained at least one neonicotinoid. They looked for traces of five of the most commonly used neonicotinoids: acetamiprid, clothianidin, imidacloprid, thiacloprid and thiamethoxam.
About 75 per cent of the world's honey is contaminated with bee-harming pesticides, a key factor behind the global decline of the crucial crop pollinators, a study has found.
"An interesting point raised in this study is that honey could be used as a tool to sample environmental contamination".
Of the contaminated samples, 30 percent contained a single neonicotinoid, 45 percent contained two or more, and 10 percent contained four or five. The highest concentrations were in honey samples from North America, Asia, and Europe.
"The study found that almost half of the honey samples exceeded a level of the pesticide that some previous research said weakens bees", asserted the report, adding: "But the pesticide makers say otherwise".
Jeffrey Donald, a spokesman for Bayer Crop Science which makes the neonic clothianidinsaid, said the study "perpetuates the myth that exposure to low levels of neonicotinoids implies risk, even though there is no compelling scientific evidence to support this conclusion".
However the impact of neonics on pollinators such as bees has always been a troubling subject for scientists around the world.
"This is an important paper if for no other reason that it will attract a great deal of attention to the mounting problem of worldwide dependence on agrochemicals, the side effects of which we know relatively little", Cameron said in an email.
Nearly half of all samples globally, contained more than one type of the pesticides, evidence that bees were often foraging in multiple sites affected by pesticides. "It was just too strong".