Microplastics in wastewater and sludge from centralized industrial wastewater treatment plants in Ho Chi Minh City, Vietnam

Microplastic pollution is a growing concern, with wastewater treatment plants (WWTPs) acting as both barriers and sources. This study quantified microplastics in two centralized industrial WWTPs in Ho Chi Minh City, Vietnam. Microplastic concentrations ranged from 0.3 to 40.4 items L −1 in wastewater and 29.6–92.0 items g −1 dry weight in sludge, predominantly fibres. Despite high removal efficiencies, 1.7 × 10 6 microplastics were discharged daily. Potential risks from sludge were also discussed. Robust multivariate regression analysis of 43 WWTPs worldwide underscored the influent concentrations as the strongest predictor influencing effluent concentrations and offering insights into potential evidence-based strategies aligned with Vietnam's 2030 plastic reduction goals. • Microplastic concentration was from 0.3 to 40.4 items L −1 in wastewater. • Sludge cake contained 29.6 to 92.0 microplastics g −1 d.w. • There was potential for microplastic contamination of various environments from WWTPs. • Influent concentration was the most influencing factor in effluent concentration.