Pesticides in Swiss orchards: from environmental reservoirs to human exposure.

One of the main challenges in understanding the fate and impacts of pesticides is to incorporate multiple environmental and human matrices and their interrelations. This study aimed to identify the most critical substances through detection frequency (DF) analysis of multiple environmental and biological matrices of Swiss study site containing orchards. A sampling campaign was conducted during the harvest season of 2021 that encompassed conventional and organic farming systems (FS), and 3 population groups (farmers, neighbors, and consumers). We analyzed 208 pesticide residues (active substances and metabolites) in a total of 62 environmental samples (soil, plant, indoor dust, water, and sediment) and 235 human samples (urine, feces, plasma, and wristbands). DDE p,p' was the substance with the highest DF in environmental samples (61%), followed by dicamba (55%), hexachlorobenzene (52%), difenoconazole (44%), and dieldrin (42%). For humans, 8 of the 20 most frequently detected substances are highly hazardous and 9 are probably hazardous to human health. Among the 6 substances detected in human blood, 2 are hazardous (piperonyl butoxide and hexachlorobenzene) and 2 are probably hazardous (fluopyram and DDE p,p'). Samples from organic FS are less contaminated than samples from conventional systems. Conventional farmers showed the highest DFs for several pesticide residues. 25% of compounds including banned substances detected in both compartments illustrates how legacy contaminants continue to dominate in the mixtures and circulate between environmental reservoirs and humans. Integrating pesticide insights from diverse matrices is crucial to advancing our understanding of pesticide exposure and designing more effective risk reduction strategies.