Occurrence and distribution of glyphosate, polar pesticides and their metabolites in honeybees (Apis mellifera): a monitoring study in six different Italian regions

The widespread use of agrochemicals has raised concerns about their impact on non-target species, particularly pollinators such as honeybees (Apis mellifera). This study investigates the occurrence and distribution of glyphosate, other polar pesticides, and their metabolites in honeybees across six regions of northern and central Italy: Lombardy, Emilia Romagna, Lazio, Tuscany, Umbria, and Marche. Honeybees serve as effective bioindicators of pesticide contamination, offering insights into environmental and ecosystem health. A total of 314 bee samples were analyzed and categorized into two groups: dead/dying bees and live bees from healthy hives. Advanced analytical techniques, including liquid chromatography-tandem mass spectrometry (LC-MS/MS) and ion chromatography-high resolution mass spectrometry (ICHRMS), were used to detect glyphosate, fosetyl, glufosinate, ethephon, and their metabolites. Results revealed glyphosate contamination in 33.4 % of the samples, predominantly in Lombardy and Emilia Romagna, where herbicide use is highest. Fosetyl residues were also detected but were more localized. Notably, there was no significant difference in glyphosate presence between dead/dying and live bees, suggesting chronic exposure rather than acute toxicity. However, higher pesticide concentrations in dead/dying bees indicate potential sublethal effects contributing to colony distress. This study underscores the importance of monitoring polar pesticides in pollinator populations and advocates for more sustainable agricultural practices. Honeybees can effectively serve as bioindicators of environmental contamination, reinforcing the One Health approach, which links environmental, animal, and human well-being. Continuous surveillance is crucial to mitigating pesticide risks and ensuring pollinator conservation.