Urban drainage channels as microplastics pollution hotspots in developing areas: A case study in Da Nang, Vietnam

This study provides information on the current situation of microplastics contamination in inland freshwater bodies in Vietnam. An urban drainage channel in Da Nang City was selected as a case study. Receiving mainly domestic wastewater and landfill leachate, the channel itself is becoming a microplastic pollution hotspot with a microplastic concentration of 1482.0 ± 1060.4 items m−3 in waters and 6120.0 ± 2145.7 items kg−1 in sediments. The dominant shapes of microplastics were fibers and fragments, in which the polymer types were mainly polyethylene, polypropylene, and polyethylene terephthalate. Microplastics with sizes ranging from 1000 to 5000 μm tended to be distributed primarily in surface waters, whereas particles from 300 to 1000 μm accumulated in sediments. The channel places Da Nang Bay at a high risk for microplastic pollution, with an estimated pollution load of approximately 623 × 106 items d−1 in dry weather. •Microplastics occurred in a drainage channel in Da Nang with high concentrations.•Fibers and fragments were predominant forms.•Main polymers types were polyethylene, polypropylene, and polyethylene terephthalate.•Significant difference in microplastic size distribution between waters and sediments•The channel conveys approximately 623 × 106 items d−1 to Da Nang Bay in dry weather.