Pesticides, lead and pollutants in honey: what has been measured

The short answer

Bees forage over several square kilometres, and what lands on flowers or blows in the air ends up in small amounts in nectar, pollen and wax. So honey can contain pesticide residues and metals. The question is how much, and the surveys below give measured answers. None of them measures what is in a particular jar.

Pesticide residues

The largest worldwide survey tested 198 honeys for five neonicotinoid insecticides. Three-quarters contained at least one, nearly half contained two or more, and one in ten contained four or five. Where they were found, the average was 1.8 nanograms per gram — below the maximum residue levels set for human consumption.

The authors' conclusion was about bees, not people. Honey is what a colony eats through the winter, so residues in it measure the bees' exposure, and they found that exposure worldwide. Whether a given level harms bees is a separate question, answered by different studies; the neonicotinoid and pesticide-mixture guides cover that evidence.

Metals, and honey as a record of the city

Researchers in Vancouver sampled honey, bees, pollen and propolis across the metropolitan area. Honey from urban and industrial sites carried more lead, zinc, vanadium and titanium than suburban and rural honey. The differences showed up at the scale of about a kilometre, which makes a hive a cheap monitor of its neighbourhood. Across 246 honey samples collected from 2014 to 2019, lead ranged from 1 to 181 ng/g. The researchers also found the bees were not taking up enough lead, cadmium or copper to harm the colony.

The top of that range is above the 0.10 mg/kg (100 ng/g) limit Great Britain sets for lead in honey sold as food. That comparison is HoneyHQ's, not the study's. The study was not a food-safety survey: it mapped metals, and one high sample says nothing about typical urban honey. It is still a reason why honey from beside a smelter, a port or a busy road is not the same product as honey from open country.

A wider study compared honey from four countries and more. In New York City, metals tied to traffic and infrastructure were more concentrated than in honey from upstate. At the largest scale, the isotopic make-up of the lead separated North American, European and New Zealand honey. The pattern still reflects the leaded petrol burned through the twentieth century, decades after it was phased out.