Nanopolystyrene size effect and its combined acute toxicity with halogenated PAHs on Daphnia magna

• Published in: The Science of the total environment Vol. 912; p. 169435
• Main Authors: Sun, Qing, Yang, Yu-Ting, Zheng, Zi-Yi, Ni, Hong-Gang
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.02.2024
• Subjects: Animals; Antagonistic; Combined toxicity; Daphnia; Daphnia magna; Halogenated polycyclic aromatic hydrocarbons; Nanopolystyrene; Polycyclic Aromatic Hydrocarbons - analysis; Polycyclic Aromatic Hydrocarbons - toxicity; Polystyrenes - toxicity; Size effect; Water; Water Pollutants, Chemical - analysis; Combined toxicity; Antagonistic; Nanopolystyrene; Size effect; Halogenated polycyclic aromatic hydrocarbons
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.169435

Nanoplastics (NPs, diameter <1 μm) not only have toxicity but also change the toxicity of other pollutants in water. To date, the nanopolystyrene (nano-PS) size effect and its combined toxicity with halogenated polycyclic aromatic hydrocarbons (HPAHs) remain unclear. In this study, the single toxicity, combined toxicity, and mode of action of the binary mixture of polystyrene (PS) and HPAH were examined. At the same time, the nano-PS size effect on combined toxicity was also discussed. According to our results, the 48 h acute toxicity test results showed that 30 nm PS was highly toxic (EC50–48 h = 1.65 mg/L), 200 nm PS was moderately toxic (EC50–48 h = 17.8 mg/L), and 1 μm PS was lowly toxic (EC50–48 h = 189 mg/L). The NP toxicity decreased with increasing size. HPAHs were highly toxic substances to Daphnia magna (EC50–48 h = 0.12–0.22 mg/L). The mode of action of PS and HPAHs was antagonistic according to the toxicity unit method (TU), additive index method (AI), and mixture toxicity index method (MTI). The size effect of nano-PS operates via two mechanisms: the inherent toxicity of nano-PS and the sorption of pollutants by nano-PS. The former impacts the combined toxicity more than the latter. In the binary mixed system, the larger the particle size and the higher the proportion of NPs in the system, the less toxic the system was. Linear interpolation analysis can be used to predict the combined toxicity of a mixed system with any mixing ratio. [Display omitted] •The nanopolystyrene (nano-PS) toxicity decreased with increasing size.•Larger particle size and higher proportion of nano-PS lead to less combined toxicity.•Sorption and own toxicity of nano-PS have opposite effects on the combined toxicity.•The inherent toxicity of nano-PS impacts the combined toxicity more than its sorption.•The MoA of mixtures of HPAH and nano-PS should be antagonism.