The joint research of the nonprofit Hives for Humanity and the Pacific Centre for Isotopic and Geochemical Research lab at the University of British Columbia has produced some interesting conclusions about urban beehives. It turned out that, besides satisfying our sweet cravings and providing us with honey-related health benefits, urban honey can provide another, unusual service. It can serve as a pollution indicator.
The study has been published in Nature Sustainability, and it is the first of its kind in North America. The team tested the honey from six Vancouver neighborhoods from varying districts (urban, industrial, residential and agricultural) for levels of lead, copper, zinc, and other pollutants. Lead (Pb) is a well-known pollutant in urban and industrial areas, capable of causing neurological damage and other health issues when the levels are high.
In general, the study showed that the concentration of pollutants – especially lead – increased if the hives were close to heavy traffic, areas with high urban density, and shipping ports. For example, in the honey from hives closer to the metro, there was a higher chance of finding elevated lead concentrations.
The honey collected near the Port of Vancouver showed elevated trace element concentration, and interestingly, higher levels of certain lead isotopes (206Pb, 208Pb) than in any other local environmental proxy (oysters, river sediment, volcanic rocks). The team concluded that the lead could have come from Asian anthropogenic sources.
The hives at the edge of Vancouver, near the neighboring agricultural towns, produced honey with higher levels of manganese. That is a characteristic sign of pesticide use in the area.
What makes honey such an effective tool for detecting and “storing” local pollution?
When a pollutant is released into a particular environment, it enters the soil, the air, and water – therefore, it gets picked up by plants and accumulates in their pollen. Bees repeatedly collect pollen within one or two-mile radius from their home. Thus, a chemical blueprint of their immediate environment is stored in the honey made from that pollen.
It is important to note that the findings of this study, and other similar studies worldwide, do not indicate the quality and safety of honey. The polluting elements are found only in traces, well below the limits considered safe human consumption. Apart for a few spikes in pollution here and there, according to its honey, Vancouver seems to be a very clean city – and therefore a good home for bee hives.
A way to step up the research would be to note the specific isotopic signatures of a wide range of pollutants in the city and then pinpoint them inside the local honey. The project could take years, but it should give the city officials and citizens a unique “honey-colored” pollution map – and a good insight into the sources of pollution.
The study is an important contribution to the emerging field of urban geochemistry, which often relies on readily available biomonitorsto determine the source and the lifecycle of pollutants in cities.
Smith, K.E. et al. 2019. Honey as a biomonitor for a changing world. Nature Sustainability 2, 223–232 (2019) https://www.nature.com/articles/s41893-019-0243-0
Sloat, S. 2019. Urban Honeybees Are Precise Pollution Detectives. Lead Study Finds. Inverse. https://www.inverse.com/article/53950-bee-hive-honey-pollution-monitors
Kaufman, R. 2017. Can Honeybees Monitor Pollution?. Smithsonian Magazine https://www.smithsonianmag.com/innovation/can-honeybees-monitor-pollution-180967431/