Associations between pesticides in honeybees/hive products and adjacent land use in a rural region of Taiwan

Pesticide contamination in honeybees may be impacted by land covers surrounding the apiaries. We conducted a field study to explore the associations between pesticides in honeybees/hive products and land use (i.e., upland field, orchard, forest) in eastern Taiwan. Twelve apiaries collaborated with this study, providing bioindicating samples of honeybees (healthy, sick, dead) and hive products (beeswax, bee pollen), which were collected during the blooming season (May through September). Samples were analyzed for 14 pesticides (six insecticides, five herbicides, three fungicides) using gas or liquid chromatography coupled with mass spectrometry. Geographic information system technology was employed to determine the proportions of different land covers within the designated buffer zones. All sample matrices except healthy bees carried high pesticide levels, with mean total concentrations exceeding 270 ng/g. Significant correlations (ρ > 0.59, P < 0.05) were observed between pesticides in the apiarian samples and upland fields, suggesting a contribution of pesticides from upland field farming. Negative correlations (ρ < −0.58, P < 0.05) were found between fungicide levels in the samples and the presence of forests within the buffer zones, indicating minimal agricultural activity in forested areas. Orchards appeared to have little direct impact on pesticide levels in the bioindicators; while negative correlations were noted between pesticides and orchards in the long-distance buffer zones, they may have been confounded by other factors. Overall, our findings suggest that land use may play a role in pesticide contamination in honeybees and hive products, but the associations may be influenced by non-agricultural pesticide sources.