Analysis of samples from National Honey Monitoring Scheme for pesticide residues to quantify pesticide exposure risk to honeybees

Defra require the development of indicators that can be used to monitor changes in the environment and progress towards the 25 Year Environment Plan (YEP) goals. Honeybees are key biological endpoint indicators for both regulatory testing and field exposure to agrochemicals. Due to their large foraging ranges and generalist feeding habits, honeybees can integrate information on exposure risk to these products at a semi-landscape scale. The citizen science based National Honey Monitoring Scheme (NHMS - an output of the ASSIST Achieving Sustainable Agricultural Systems project) provides a resource to quantify agrochemical residues in honey both at a national scale and over a temporal scale. This scheme has been running since 2018 (although pilot studies collecting honey nationally preceded this) with currently c. 1200 amateur and professional bee keepers providing honey samples and associated meta-data (location, honey yield, disease rates etc.). Bee keepers provide honey samples both for general interest and in exchange for metabarcoding of samples to quantify the floral origin of their honey. Here we pilot the potential use of the NHMS as a mechanism for assessing honeybee exposure risk to agrochemical residues both over time and at national scales. This was based on chemical analysis of 100 honey samples collected in 2019. For neonicotinoid pesticides we combined the results with historic residue analysis from 2014-2017. This latter assessment provided an indication of the viability of this approach to contribute to an H4 indicator of exposure and adverse effects of chemicals on wildlife.