Toxicity of triclosan adsorbed in microplastic in fish hepatoma cell line, PLHC-1

Triclosan (TCS), a widely used antibacterial agent in personal care products, is frequently detected in water bodies along with microplastics, particularly polypropylene (PP). These microplastics can absorb and transport chemical pollutants, potentially affecting the distribution of these contaminants and increasing ecological risks. However, the role of PP microplastics in the movement of TCS and their effects on aquatic organisms remain largely unexplored. This study investigated the adsorption of TCS onto PP microplastics under different pH conditions and evaluated the cytotoxicity and oxidative stress induced by TCS-adsorbed PP in the fish hepatoma cell line PLHC-1. TCS adsorption onto PP microplastics was studied under different pH conditions, with characterization performed using Fourier-transform infrared spectroscopy (FT-IR). To determine biological toxicity, PLHC-1 cells were exposed to PP microplastics with adsorbed TCS, and cell viability along with intracellular reactive oxygen species (ROS) production was measured. FT-IR spectroscopy showed characteristic TCS-associated peaks on PP under the unadjusted pH condition (pH 6.67), whereas these peaks were not clearly observed under the acidic condition (pH 3.96). The presence of TCS-adsorbed PP microplastics led to a significant reduction in the viability of PLHC-1 cells, which was dependent on the concentration of TCS. For PP/TCS prepared using 160 μg/mL TCS, cell viability decreased to approximately 50%, while intracellular ROS increased to 539.62% of the control. The study's results indicate that PP microplastics can associate with TCS and the resulting PP/TCS material retains biologically relevant cytotoxic and oxidative effects in PLHC-1 cells. This suggests that PP microplastics could serve as carriers for toxic substances in aquatic environments, thereby increasing the ecological threats to aquatic organisms.