Honey as a biomonitor for a changing world

Urban geochemistry is an emerging field in which key scientific and societal challenges, including rapid urbanization and population growth, compel investigation of readily accessible biomonitors to determine the source, transport and fate of heavy metal pollutants in cities. Lead isotopic analyses of honey have recently proven its efficacy as a biomonitor for Pb source apportionment applications. We collected honey directly from hives in six geographical sectors in Vancouver, British Columbia (Canada) to investigate the presence of potential pollutants from varying zoning districts: urban, industrial, residential and agricultural. Systematic variations in trace element concentrations and Pb isotopic compositions of the honeys reflect proximity to anthropogenic land-use activities such as shipping ports and heavy traffic. Honey sampled from downtown hives, near the Port of Vancouver, shows elevated trace element concentrations compared with suburban and rural honey, and distinctly higher Pb-208/Pb-206 (that is, less radiogenic) compared with local environmental proxies (for example, oysters, Fraser River sediment and volcanic rocks), indicating possible input from Asian anthropogenic sources. This study presents the first Pb isotope data for North American honey, and supports the combined use of trace elements and Pb isotopic compositions in honey as a geochemical biomonitor.