Naturally occurring environmental PFAS mixtures induce significant oxidative damage and nuclei fragmentation in Dendrobaena veneta

Abstract

Among persistent pollutants, perfluoroalkyl substances (PFAS) have garnered significant attention due to their ubiquitous presence in the environment and their established toxicity to humans. While numerous studies have investigated the impact of PFAS on various wildlife species, there remains a critical need to understand the specific responses of key bioindicator species. This study focuses on the earthworm Dendrobaena veneta as a crucial soil toxicity bioindicator to assess the potential toxicity of environmentally relevant PFAS mixtures. Earthworms were chronically exposed for 30 days to three PFAS mixtures at concentrations ranging from ng L⁻¹. Genetic damage was evident in coelomocytes, with a 50 % reduction in healthy nuclei. Evaluation of the reactive oxygen species (ROS) content revealed the mitochondria as the primary site of impact of PFAS. ROS production was higher in all PFAS-exposed groups. Antioxidant capacity was significantly impaired following PFAS exposure, indicating an ongoing response in exposed organisms. Furthermore, given the scavenger power against ROS, the content and gene expression of metallothioneins (MTs) were evaluated. The results reported a dose-dependent increase in expression levels at least 10 times higher under PFAS exposure. A similar trend was observed for the content of MTs, which increased in the three experimental groups 2-fold, 4-fold, and 6-fold, respectively.