Studying the combined phytotoxicity of PFOA with Fe2O3 or MnO2 nanoparticles (NPs) is paramount for addressing the remediation of PFOA-contaminated agricultural soils and assessing the efficacy of nanoparticle-assisted phytoremediation strategies. By exposing radish plants to PFOA with/without Fe2O3 or MnO2 NPs for 60 days, this study delved into radish biomass, PFOA accumulation, chlorophyll pigments, antioxidant defenses, and nutrient contents. Key findings showed that PFOA at environmentally relevant levels (20 mu g/kg) were highly toxic to radish plants. PFOA accumulated significantly in radish organs, especially in the shoots. Additionally, PFOA exposure had a detrimental impact on radish growth. However, the application of Fe2O3 and MnO2 NPs facilitated the translocation of PFOA up to shoots, thereby reducing its accumulation in the edible roots. Additionally, they could significantly increase radish biomass and mitigate the damages caused by PFOA, evidenced by lower MDA contents and higher amino acid contents. This study highlights the potential of nanoparticle-enhanced phytoremediation as an effective approach for PFOA-polluted agricultural soils. By promoting the translocation of harmful pollutants away from edible plant parts and enhancing plant growth and resilience, Fe2O3 and MnO2 NPs offer a promising avenue for sustainable soil remediation strategies.

Hexafluoropropylene oxide dimer acid (HFPO-DA), an emerging perfluoroalkyl substance (PFAS) that is replacing traditional PFASs, has a wide range of industrial applications and has been detected globally in the environment. However, it remains unclear whether HFPO-DA, is genuinely less toxic than perfluorooctanoic acid (PFOA) in terms of soil environmental hazards. Therefore, this study aimed to compare differences in toxicity between PFOA and its substitute, HFPO-DA, in a common species of earthworm, Eisenia fetida. Our findings revealed that both HFPO-DA and PFOA caused oxidative damage, apoptosis, reproductive disorders, and neurotoxicity in E. fetida at a concentration of 0.2 mg/kg following exposure for 28 d. Specifically, at the molecular level, PFOA resulted in a significant decline in total antioxidant capacity and lipid peroxidation, whereas HFPO-DA did not have the same effect. The Integrated Biomarker Response (IBR) index, based on the indicators studied, showed that HFPO-DA exhibited lower toxicity than PFOA. The transcriptomic results suggest that HFPO-DA can induce neurotoxicity, similar to PFOA; however, the specific mechanisms differ. Although HFPODA appears to be less toxic than PFOA to E. fetida, its potential hazards at the transcriptional level, affecting different pathways, require further investigation. This study provided new insights into the safety of HFPO-DA as a novel substitute for PFOA.

As a class of emerging persistent organic pollutants (POPs), per- and polyfluoroalkyl substances (PFASs) are widely detected in the soil environment, posing a significant threat to the soil ecosystem and human health. Therefore, it is necessary to study the ecotoxicological effects of PFASs in soil. In this study, we conducted a comprehensive review of the toxic effects of PFASs on earthworms at the individual and sub-individual levels, including survival status, body weight, reproduction, oxidative damage, genes, metabolism, and so on. Results showed that earthworms exposed to certain concentrations of PFASs display various pathological symptoms on their body surfaces, a decrease in body weight and reproductive rate, and even death. The LC50 values of PFOS to earthworms (365-1404 mg/kg) are consistently lower than those of PFOA (544-1307 mg/kg) under the same exposure condition, indicating a higher toxicity of PFOS compared to PFOA. At the sub-individual level, PFASs may induce oxidative stress, DNA damage, aberrant gene expression, and metabolic disruption in earthworms. PFOS induced disruption of the nervous and metabolic system, PFHxS disrupted energy balance and elicited inflammation, and PFBS induced cell apoptosis in earthworms. Compared to PFOS, PFHxS may induce a greater degree of oxidative stress and damage, and 6:2 Cl-PFESA (F-53B) exhibited a greater propensity to disrupt the extracellular matrix and induce cellular ferroptosis and apoptosis in earthworms. At environmentally relevant concentration levels, PFOA induces significant dysregulation of pathways related to amino acid, energy, and sulfur metabolisms within earthworms. Bioavailability and bioaccumulation capacity of PFASs are important factors in determining their toxicological effects in soil, which is influenced by the molecular structure of PFASs and the combined effects of various environmental factors, such as soil organic matter composition and content, pH, PFAS concentrations and exposure duration. Finally, existing research deficiencies and future directions about the toxicological research of PFASs on earthworms are proposed, aiming to offer reference for ecological risk assessment of PFASs-contaminated soil.