Distribution Characteristics and Source Analysis of Microplastics in Urban Freshwater Lakes: A Case Study in Songshan Lake of Dongguan, China

A study on transboundary governance of marine plastic debris-the case of an adjacent waters between China and Taiwan

This study aimed to construct a transboundary marine governance mechanism in the Kinmen-Xiamen waters through literature review, field survey, in-depth interview, and expert opinion survey. The study finds that monsoons, ocean currents, and tides are the main factors affecting the drift of marine debris in the Xiamen Sea area to the beaches of Kinmen. The marine debris mainly included marine plastic debris (MPD), bamboo, and wood in Kinmen and was documented impacting a variety of species, including the horseshoe crab to marine mammals the IndoPacific dolphin. In addition, the problem of marine micro-plastic pollution is becoming increasingly worrisome and hazardous to rare creatures in the Xiamen Sea area. The pollution sources of MPD in Xiamen Bay included coastal tourism activities, micro-plastic discharged from sewage treatment plants, plastic waste produced by lost and discarded marine aquaculture, and plastic drifting terrestrial waste transported from the Jiulong River Basin. Our results show that microplastic pollution in the Kinmen-Xiamen waters may have a greater impact on marine ecology and the surrounding environment. The relevant transboundary marine governance mechanisms are discussed in this study.

Research status and prospects of microplastic pollution in lakes

As an emerging pollutant, microplastics have attracted widespread concern around the world. Research on microplastics was first conducted in oceans, and in recent years, inland water, especially lakes, has gradually become a hot spot. This paper systematically reviews the sampling, separation, purification, and identification technologies used to assess microplastics in lakes and summarizes the occurrence of lake microplastics worldwide. The results show that microplastics are widespread in lake water and sediment. There are obvious geographical differences in the occurrence of microplastics. The abundance of microplastics in different lakes varies greatly. The forms are mostly fibrous and fragments, and the main polymers are polypropylene (PP) and polyethylene (PE). Previous papers have failed to comment in as much detail on the microplastic sampling techniques employed within lake systems. The sampling and analysis methods are critical to accurately evaluating contamination results. Due to the widespread presence of microplastics and the lack of uniform standards, there are various sampling methods. Trawls and grabs are most widely used in the sampling of lake water bodies and sediment, and sodium chloride and hydrogen peroxide are the most widely used media for flotation and digestion, respectively. In the future, it will be critical to establish unified standards for lake microplastic sampling and analysis technology, further explore the migration mechanism of microplastics in lake systems, and pay attention to the impact of microplastics on lake ecosystems.

Microplastics (MPs) distribution in Surface Sediments of the Freidounkenar Paddy Wetland

There is an urgent need to increase knowledge on the distribution of microplastics (MPs) in wetlands because these are sites of special ecological value and the ever-growing use of plastic can threaten such fragile ecosystems. This research assesses, for the first time, the occurrence of MPs in surface sediment of the Freidounkenar International Wetland (Northern Iran), a valuable habitat for migratory birds. A total of 1368 MP/kg were identified in the surface sediments of the wetland. The distribution of MPs in sediments per area was Ezbaran (36.5%), Western Sorkhrood (32.0%), Freidounkenar (20.1%) and Eastern Sorkhrood Ab-bandans (11.4%). The most contaminated sites were located close to agricultural fields, Damgahs (agroecosystems for birds), fishing areas and roads. Fibers and white-transparent and black-grey MPs constituted the dominant MPs in the surface sediment. The most abundant MPs were < 250 μm and these were made of nylon, polypropylene-low density polyethylene copolymer, polystyrene, low density polyethylene and polypropylene. The identification of MPs was carried out visually and supported with Scanning Electron Microscopy (SEM)-Energy Dispersive X-Ray (EDX) and micro-Raman techniques. There were weathering signs in large proportion of the MPs, according to SEM analysis, which evidences their formation from the degradation of other plastics. This is a comprehensive study on MPs in surface sediment of this sensitive internationally recognized ecosystem with high ecological value.

Distribution, characteristics, and risk assessments analysis of microplastics in shore sediments and surface water of Moheshkhali channel of Bay of Bengal, Bangladesh

Microplastic pollution in various ecosystems has gained significant attention across the globe. Due to ubiquitous abundance, terrestrial and aquatic ecosystems at regional scales are polluted via uncontrolled anthropogenic actions. Therefore, this study investigates microplastic pollution and distribution in sediments and surface water of the Moheshkhali channel of Bangladesh, Bay of Bengal, along with their shape, size, color, and polymeric analysis. It has been observed that both sediments and surface water are significantly contaminated with microplastics at 14 sediments and 12 surface water sampling sites. 291 particles of microplastic were observed in two quadrants, separated 10-m away from each other, across 14 sediment sampling sites, with average concentrations registered in the range of 6.66 to 138.33 particles/m². At the same time, 163 particles were observed across 12 sampling sites in the surface water, ranging from 0 to ~0.1 particles/m³. Various shapes, like films, fragments, fiber/lines, foams, and pellets (resins), were observed extensively in the Moheshkhali channel. Besides, various risk assessments, like contamination factors, polymeric risk assessment, pollution risk index, and pollution load index, were analyzed for each sampling site across the channel. Pollution load index (PLI) of shore sediments and surface water were 2.51 and 1.67, respectively, indicating significant pollution in the Moheshkhali channel. This research investigation provides insight into anthropogenic activities and baseline microplastic pollution in the Moheshkhali channel of Bangladesh, which helps to prepare robust strategies for conservation and management to deal with such environmental issues.