Biomonitoring of honey metal(loid) pollution in Northwest England by citizen scientists

Honey can be used to biomonitor contaminants, as honeybees can bioaccumulate both organic and inorganic (e.g., metal(loid)) contaminants from the total environment. Honey chemical composition can be influenced by natural and anthropogenic activities. Metal(loid) concentrations in honey samples collected by citizen scientist beekeepers in northwest England during fall 2018 were measured to assess potential sources from current and historical land use. Spatial distribution of honey metal(loid) concentrations was assessed using a geographic information system (GIS) using postal codes to identify beehive locations of citizen scientists and analyzed using inductively coupled plasma mass spectrometry (ICP-MS). GIS tools were used to correlate metal(loid) concentrations with local pollution point sources and soil geochemistry databases. The Greater Manchester area had higher mean As and Cd concentrations in honey (180 ug/kg and 398 ug/kg, respectively) compared to global means 25 ug/kg and 150 ug/kg, respectively), but mean honey Cu, Pb and Zn concentrations were lower (225 ug/kg, 260 ug/kg and 426 ug/kg, respectively) than global means (1005 ug/kg, 1470 ug/kg and 8545 ug/kg, respectively). Cadmium and Pb concentrations in honey measured in the Greater Manchester area were 398 and 260 ug/kg, respectively, which are up to two orders of magnitude higher than the recommended World Health Organization (WHO) and Food and Agriculture Organization (FAO) guidelines, which may warrant further study to determine potential health impacts from honey consumption. Landscape analysis showed no correlation between metal(loid) contaminants and beehive location. This baseline study demonstrates that honey collected by citizen scientists can be used as an effective environmental biomonitoring tool to analyze metal(loid) contaminants in urban areas.