Polycarbonate microplastics induce oxidative stress in anaerobic digestion of waste activated sludge by leaching bisphenol A

• Published in: Journal of hazardous materials Vol. 443; p. 130158
• Main Authors: Chen, Hongbo, Zou, Zhiming, Tang, Mengge, Yang, Xiao, Tsang, Yiu Fai
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.02.2023
• Subjects: Biomass viability; Bisphenol A; Oxidative stress; Polycarbonate microplastics; Reactive oxygen species; Bisphenol A; Oxidative stress; Reactive oxygen species; Polycarbonate microplastics; Biomass viability
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2022.130158

Polycarbonate (PC) microplastics are frequently detected in waste activated sludge. However, understanding the potential impact of PC microplastics on biological sludge treatment remains challenging. By tracking the changes in methane production under different concentrations of PC microplastics, a dose-dependent effect of PC microplastics on anaerobic digestion of sludge was observed. PC microplastics at 10–60 particles/g total solids (TS) improved methane production by up to 24.7 ± 0.1 % (at 30 particles/g TS), while 200 particles/g TS PC microplastics reduced methane production by 8.09 ± 0.1 %. Bisphenol A (BPA) leached from 30 particles/g TS PC microplastics (1.26 ± 0.18 mg/L) down-regulated intracellular reactive oxygen species (ROS) production, thereby enhancing enzyme activity, biomass viability, and abundance of methanogenic (Methanobacterium sp. and Methanosarcina sp.), ultimately boosting methane production. Conversely, BPA leached from 200 particles/g TS PC microplastics (4.02 ± 0.15 mg/L) stimulated ROS production, resulting in decreased biomass viability and even apoptosis. Modulation of oxidative stress by leaching monomeric BPA is an underappreciated transformative mechanism for improving the mastery of the potential behavior of microplastics in biological sludge treatment. [Display omitted] •PC microplastics exhibited dose-dependent effects on sludge anaerobic digestion.•PC microplastics at 30 particles/g TS increased methane production by 24.7 ± 0.1 %.•BPA and PhOHs were the major chemicals leached from PC microplastics.•PhOHs had no obvious effect on sludge anaerobic digestion.•BPA induced variability of intracellular reactive oxygen species production.