Microplastics, which are plastic debris with a particle diameter of less than 5 mm, have attracted growing attention in recent years. Its widespread distributions in a variety of habitats have urged scientists to understand deeper regarding their potential impact on the marine living resources. Most studies on microplastics hitherto are focused on the marine environment, and research on risk assessment methodology is still limited. To understand the distribution of microplastics in urban rivers, this study investigated river sediments in Shanghai, the largest urban area in China. Seven sites were sampled to ensure maximum coverage of the city's central districts, and a tidal flat was also included to compare with river samples. Density separation, microscopic inspection and μ-FT-IR analysis were conducted to analyze the characteristics of microplastics and the type of polymers. The average abundance of microplastics in six river sediment samples was 802 items per kilogram of dry weight. The abundance in rivers was one to two orders of magnitude higher than in the tidal flat. White microplastic spheres were most commonly distributed in river sediments. Seven types of microplastics were identified, of which polypropylene was the most prevailing polymers presented. The study then conducted risk assessment of microplastics in sediments based on the observed results, and proposed a framework of environmental risk assessment. After reviewing waste disposal related legislation and regulations in China, this study conclude that in situ data and legitimate estimations should be incorporated as part of the practice when developing environmental policies aiming to tackle microplastic pollution.

Microplastics in Freshwater River Sediments in Shanghai, China: A Case Study of Risk Assessment in Mega Cities

Microplastics in aquatic environment: Challenges and perspectives

Foliar uptake and leaf-to-root translocation of nanoplastics with different coating charge in maize plants.

Microplastics as a vehicle of heavy metals in aquatic environments: A review of adsorption factors, mechanisms, and biological effects

Microplastics as a vehicle of heavy metals in aquatic environments: A review of adsorption factors, mechanisms, and biological effects.

Microplastics and nanoplastics in the environment: Macroscopic transport and effects on creatures

Interactions between microplastics/nanoplastics and vascular plants.

Microplastics retention by reeds in freshwater environment

Recent advances on the transport of microplastics/nanoplastics in abiotic and biotic compartments.

Research progress of microplastics in soil-plant system: Ecological effects and potential risks.

Jiaxi Tao

Papers

Microplastics and nanoplastics in the environment: Macroscopic transport and effects on creatures

Interactions between microplastics/nanoplastics and vascular plants.

Microplastics retention by reeds in freshwater environment

Recent advances on the transport of microplastics/nanoplastics in abiotic and biotic compartments.

Research progress of microplastics in soil-plant system: Ecological effects and potential risks.