Release of microplastics from typical rainwater facilities during aging process

• Published in: The Science of the total environment Vol. 813; p. 152674
• Main Authors: Zhang, Xiaoran, Liu, Chao, Liu, Junfeng, Zhang, Ziyang, Gong, Yongwei, Li, Haiyan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.03.2022
• Subjects: Aging; carbon; cleavage (chemistry); drainage; environment; Environmental Monitoring; flood control; Fourier transform infrared spectroscopy; Microplastic; Microplastics; particle size; Plastics; pollution; poly(vinyl chloride); Polyethylene; polypropylenes; rain; Rainwater facility; Release; risk; roughness; stormwater; Water Pollutants, Chemical - analysis; X-ray photoelectron spectroscopy; Aging; Rainwater facility; Microplastic; Release
• DOI: 10.1016/j.scitotenv.2021.152674
• ISSN: 0048-9697; 1879-1026

As the demand for urban flood prevention and drainage increases, a large number of plastic rainwater facilities are in use. Microplastics will be released inevitably into stormwater systems during aging and hydraulic scouring processes, which could cause potential pollution risk. This study simulated the release behavior of microplastics from three typical plastic rainwater facilities including a rainwater inspection well, rainwater storage module, and rainwater pipe (mainly composed of high-density polyethylene, polypropylene, and polyvinyl chloride, respectively) under the effects of aging and hydraulic scouring. After 15–45 days of UV aging and 72 h of hydraulic scouring, the surfaces of the three facilities were found to exhibit increases in roughness, cracks, folds, and cavities, with the most pronounced changes occurring in the rainwater storage module. As the aging time increased, oxygen-containing functional groups formed and led to carbon chain scission. Fourier transform infrared spectroscopy (FTIR), two-dimensional correlation spectroscopy (2D-COS) and X-ray photoelectron spectroscopy (XPS) of facility surfaces showed that the formation of oxygen-containing functional groups was an important factor affecting the release of microplastics. The amount of microplastics released from the three facilities ranged from 160 to 1905 items/g (microplastics/facilities), following in the order of rainwater inspection well > rainwater storage module > rainwater pipe. The particle size of the released microplastics ranged from 3 to 1363 μm, with 10–30 μm accounting for the greatest proportion of particles, 50.10%. The size of microplastics released from the rainwater inspection well and rainwater storage module increased with the aging degree, while the release from the rainwater pipe decreased. The release behavior depends mainly on the composition of the materials and the aging time. Thus, microplastics can be released from plastic rainwater facilities under suitable conditions. The results can be used to further evaluate microplastic pollution caused by urban rainwater facilities. [Display omitted] •O-containing groups on facility surfaces are key to the release of microplastics.•Released microplastics range from 160 to 1905 items/g following HDPE>PP > PVC facility.•Released microplastics range from 3 to 1363 μm, predominant with 10–30 μm fraction.•Release of microplastics increases with aging time, especially for the small size.•Release of microplastic mainly depends on the composed materials and aging time.