Nanoplastics influence the perfluorooctane sulfonate (PFOS) mediated toxicity on marine mussel Perna viridis: Single and mixture exposure study

Abstract

Nanoplastics (NPs, <1000 nm) may adsorb organic pollutants in the aquatic environment, thereby, influencing their bioavailability to organisms. This study aims to investigate the individual and combined toxicity of perfluorooctane sulfonate (PFOS) and virgin yellow-green fluorescent polystyrene NPs (200 nm) at sub-lethal doses on the marine mussel Perna viridis. Our results demonstrated that both PFOS single and PFOS-NP co-exposure at 1000 μg/L significantly increased PFOS distribution in the gills, gonads, and visceral mass (p < 0.05), compared to the control. Further, PFOS single and PFOS-NP co-exposures at 100 and 1000 μg/L significantly increased the reactive oxygen species (ROS) levels in mussel tissues that consequently altered the responses of antioxidant entities including MDA, CAT, SOD, GR, and GST. The transcriptional profiling of oxidative stress-related genes (cyp4, hsp22, hsp60, gst-omega, and gst-pi), showed significantly downregulated expressions at the lowest level of co-exposure (PFOS 10 μg/L) in all tissues, especially in gills, compared to the control group. Overall, the enhanced integrated biomarker response (EIBR) revealed PFOS-NP co-exposure at 1000 μg/L, as the most stressful circumstance to induce mixture toxicity, at which more structural damage to the gills and gonads were observed than single PFOS/NPs exposure. In summary, the co-exposure significantly enhanced the PFOS bioaccumulation and ROS levels in mussel tissues, resulting in altered antioxidant and genetic responses, suggesting that NPs could affect the distribution of PFOS between P. viridis and seawater. Hence, further studies should be conducted to unveil the interactive toxic effects of NPs and PFOS on marine organisms.