Occurrence and distribution of microplastics in an urban river: A case study in the Pearl River along Guangzhou City, China

In recent years, microplastics have emerged as a new marine pollutant and have attracted wide research attention. As the main activity areas of human beings in the coastal environment, gulfs have always been the hotspots of marine pollution. However, the distribution of microplastics in most small and medium-sized coastal environments has been rarely reported in China. To understand the characteristics of microplastic pollution in small and medium-sized inshore bays in China, the main types, abundance, and spatial distribution characteristics of microplastics in the surface water and sediments in Haizhou Bay of Jiangsu province were studied by qualitative and quantitative methods. The results showed that the abundances of microplastics in the surface water and sediments of Haizhou Bay were (2.60±1.40) n·m-3 and (0.33±0.26) n·g-1, respectively. In the domestic offshore environment, the abundance of microplastics was at a low level in the surface water, but at a high level in the sediments in Haizhou Bay (0.33-545.00 n·m-3 and 0.07-2.58 n·g-1, respectively). The range of size distribution of microplastics in water and sediments was 0.08-13.48 mm and 0.04-14.74 mm, respectively. More than 60% of the microplastics in water and sediments were small particles of sizes less than 2.00 mm. The shape of microplastics in Haizhou Bay was mainly fibrous, accounting for 92%. The main colors were blue and black, accounting for 70%. The materials were mainly man-made fibers and PET, accounting for 79.4%. There was a significant correlation between the distribution of microplastics in surface water and suspended matter concentration (P<0.05). The distribution of microplastics in sediments was affected by many factors, and its distribution pattern between the distribution of microplastics in surface water and the distribution of particle size in sediments was quite different. Through analysis of the morphological characteristics and composition of microplastics, the results showed that the microplastics in Haizhou Bay mainly come from mariculture and coastal land sources.

Microplastics (MPs) are globally recognized as an emerging environmental threat, particularly in the aquatic environment. This study presents baseline data on the occurrence and distribution of MPs in sediments and surface water of major rivers in southwestern Nigeria. Microplastics were extracted by density separation and polymer identification using Fourier transformed infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR). The abundance of MPs in surface sediment and water samples across all locations ranged from 12.82 to 22.90 particle/kg dw and 6.71 to 17.12 particle/L during the dry season and 5.69 to 14.38 particle/kg dw and 12.41 to 22.73 particle/L during the wet season, respectively. On average, fiber constituted the highest percentage of MP in sediments (71%) and water (67%) while foam accounted for the lowest values of 0.6% and 1.7%, respectively. Polypropylene(PP) and polyethylene (PE) were the main MPs across all locations based on Fourier transform infrared spectroscopy (FTIR). MPs of size < 1mm were the most abundant (≥ 55%) on average in both water and sediments. The study identified run-off from human activities and industrial wastewater as potential sources of MP exposure based on positive matrix factorization. The study suggests assessing the impact of different land-use activities on MPs occurrence and distribution in addition to quantifying MPs in seafood as a way forward in food safety management systems for further studies. This study confirmed the occurrence and widespread distribution of MPs in surface water and sediments and provides a database on MP pollution in Nigeria.

Occurrence, characterization, and source delineation of microplastics in the coastal waters and shelf sediments of the central east coast of India, Bay of Bengal.

Distribution and risk assessment of microplastics in Liujiaxia Reservoir on the upper Yellow River

Microplastic pollution characteristics and ecological risk assessment in the Wuding River Basin, China

A case study of distribution and characteristics of microplastics in surface water and sediments of the seas around Shenzhen, southern coastal area of China

Distribution of microplastics in surface water and sediments of Qin river in Beibu Gulf, China

Microplastic is an emerging global pollutant that have attracted a great deal of attention from researchers and the public. Guangdong Province has a large population and a relatively well-developed economy, but lacks a modern pollution control system. Guangdong has a long coastline with varying levels of pollution, and little research has been conducted on microplastics. Therefore, we investigated the level of microplastic pollution in coastal areas of Guangdong Province, and the abundance of microplastics in surface waters and sediments at 13 sampling sites. The abundance of microplastics in surface water and sediment samples ranged from 850 to 3500 items/L and 433.3 to 4166.3 items/kg, respectively. Fiber is the main type of microplastics in both surface water and sediment. The sampled microplastics were typically transparent. Raman results show that the surface water sample mainly includes rayon (38.2%), polyethylene terephthalate (16.4%), and ethylene/vinyl acetate copolymer (12.7%). This study used the pollution load index method to evaluate the pollution risk of microplastics along the coast of Guangdong, and provided the basis for the formulation of environmental policy.

The occurrence and abundance of microplastics in surface water and sediment of the West River downstream, in the south of China

Influence of ongoing discharge from multiple wastewater treatment plants on microplastic patterns in small-scale receiving rivers

Rivers have been a subject of great concern in recent years as they have been found to be the critical path for the transmission of microplastics from terrestrial land to the ocean. However, the pollution status of microplastics and their behavior in the surface waters and sediments of urban rivers located in different urban areas remain unclear. In this study, 16 samples of surface water and sediment from eight rivers in the central and suburban areas of Shanghai Megacity were obtained and analyzed. High-speed cameras and Fourier transform infrared spectrometers were used to identify the abundance, size, color, shape, type, and other characteristics of microplastics in these samples. The results showed that the average abundance of microplastics in the surface waters of urban rivers in Shanghai Megacity was (7.5±2.8) pieces·L-1, while the corresponding average abundance in the sediment reached (1575.5±758.4)pieces·kg-1 (wet weight). The abundance of microplastics was found to increase with the decreasing particle diameter. Among which, microplastics with a size of less than 500 μm, as well as the fibrous shape, transparent color, and Polyester composition, have always dominated in the urban rivers in Shanghai megacity. Comparably, microplastics in the sediments were more diverse in their morphology features and polymer compositions. Microplastic pollution in the urban rivers in Shanghai megacity was severe in comparison to that in other urban rivers worldwide. Among various urban rivers, the distribution of microplastics with different morphology features and polymer compositions is greatly influenced by a number of factors including the source (e.g., mainly laundry wastewater, personal care products, and refuse plastic waste), hydrodynamic conditions, and the physical and chemical properties of plastics. Furthermore, the pollution behavior (i.e., source, transmission, and fate) of microplastics occurring in urban rivers is discussed, and the potential impacts of various environmental factors are explained.

Urban natural wetland as a sink for microplastics: A case from Lalu Wetland in Tibet, China

BackgroundThe Yangtze Estuary acts as gateways where microplastics transport from freshwater into marine environments, with one of the largest discharge volumes in the world. The occurrence of microplastics in surface water and sediments of the Yangtze Estuary has been reported. However, little is known about microplastics in and around Chongming Island in the estuary. In this study, the distribution of microplastics in surface water and sediments of Chongming Island was investigated and compared in different environmental medium.ResultsAbundances of microplastics in surface water and sediments were in the ranges of 0–259 items m− 3 and 10–60 items kg− 1 dry weight, respectively. Microplastics were more abundant in the surface water of the Yangtze River shores than in the inland rivers (p < 0.01). Proportions in fiber form in surface water and sediment were 33% and 67%; and those in fragment form were 39% and 24%. Most particles (> 72%) were < 1 mm in the longest dimension; 65% were white and 30% were transparent. Of the 11 compositions identified, polyethylene, polypropylene, and α-cellulose predominated in both phases.ConclusionThis is the first study to focus on microplastics in inland watercourses on Chongming Island and along the Yangtze River’s shores in both phases. There were differences between the island and estuary in composition and density due to the distinct vertical mixing processes. The in situ filtration of surface water (100 L) sampling method was well employed in various freshwater environments and free of plastic materials in front of the filter, analysis results of which provided an important baseline reference for evaluating microplastic pollution in the Yangtze Estuary.

Microplastic abundance, distribution and composition in water, sediments, and wild fish from Poyang Lake, China

Microplastics are considered emerging pollutants and already currently present in measurable quantities in aquatic ecosystems. However, information on the current status of microplastic pollution in the upper Yangtze River, the most important water body in China, is insufficient. In the present study, the abundance and distribution of microplastics in the surface water and sediments were investigated to obtain the characteristics of microplastic pollution in Yangtze River along Chongqing City. Ten sampling sites along Yangtze River in the Chongqing urban area were selected to collect surface water and sediment samples. Abundance and morphological characteristics of microplastics were determined by counting using a digital stereo microscope. Micro-Fourier transform-infrared spectroscopy (μ-FTIR) analysis was used to identify polymer type of the microplastics. The abundance of microplastics ranged within 46.7–204 n L−1 and 100–583 n kg−1 dw (dry weight) in the surface water and sediment samples, respectively. Fibers and films were dominant in most of samples, and the average proportion of fibers reached 74.3% in surface water. Whether in surface water or sediments, most of the microplastics were less than 0.7 mm in size, and the average proportion of microplastics with a size of less than 0.3 mm reached 62.6% in the sediment samples. Moreover, fibrous and small were the primary characteristics of the microplastics. Polypropylene, polyvinyl chloride, high-density polyethylene, polyester, and wool fibers were identified in the surface water samples. The Yangtze River along Chongqing City is contaminated by microplastic, like many urban rivers. Anthropogenic activities, including sewage treatment effluents, might be the main sources of microplastic pollution in Yangtze River (Chongqing urban section). This study reveals the contamination and characteristics of microplastics in the Yangtze River along Chongqing and supplies important data for further research on microplastics in Yangtze River’s basin.