Residues of currently used pesticides in soils and earthworms: A silent threat?

Summary

Critical knowledge gaps about environmental fate and unintentional effects of currently used pesticides (CUPs) hamper the understanding and mitigation of their global impacts on ecological processes. We investigated the exposure of earthworms to 31 multiclass CUPs in an arable landscape in France. We highlighted the presence of at least one pesticide in all soils (n=180) and 92% of earthworms (n=155) both in treated crops and nontreated habitats (hedgerows, grasslands, and cereals under organic farming). Mixtures of at least one insecticide, one herbicide, and one fungicide (> limit of quantification) contaminated 90% of soils and 54% of earthworms at levels that could endanger these nontarget beneficial soil organisms. A high risk of chronic toxicity to earthworms was found (46% of samples) both in treated winter cereals and nontreated habitats considered as refuges. This may alter biodiversity, hinder recovery, and impair ecosystem functions. These results provide essential insights for sustainable agriculture and CUP regulation, and highlight the potential of pesticides as agents of global change.