Characterization and risk assessment of microplastics in laver from the Yueqing Bay

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

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

Microplastics (MPs) are ubiquitous in the aquatic environment and have received widespread attention worldwide as emerging pollutants. Urbanization and anthropogenic activities are the main sources of MPs in rivers; however, the MPs in plateau rivers with less human activities are not well understood. In this study, the pollution of MPs in the surface water and shore sediment of the Lhasa River from the Qinghai-Tibet Plateau was investigated, and a risk assessment was conducted. The abundance of MPs in the surface water and shore sediment of Lhasa River were 0.63 n/L and 0.37 n/g, respectively. MPs in surface water were mainly dominated by films (43.23%) and fibers (31.12%) in shape, transparent (54.25%) in color, and 0-0.5mm (75.83%) in size, while MPs in the shore sediment were mainly fibers (43.69%) and fragments (36.53%), transparent (71.91%), and 0-0.5mm (60.18%). PP and PE were the predominant polymer types, accounting for 44.55% and 30.79% respectively in the surface water and 32.51% and 36.01% respectively in the shore sediment. More notably, the polymer pollution index (H) of MPs in the Lhasa River was at hazard level III due to the high risk caused by PVC, but the pollution load index (PLI) was low at hazard level I. This study reveals that the remote river in the Qinghai-Tibet Plateau are polluted by MPs, and their potential risks to the vulnerable ecosystem deserve attention.

The water environment capacity of urban parks is small, and their self-purification ability is poor. They are also more likely to be affected by microplastics (MPs), which cause an imbalance of the water micro-ecosystem. Based on the functional characteristics of parks (comprehensive park, community park, and ecological park), this study investigated the distribution characteristics of MPs in the water of Guilin parks through spot sampling, microscopic observation, and Fourier transform infrared spectroscopy. In addition, the pollution risk index and the pollution load index were used to evaluate the pollution risk of MPs.The results showed that the abundances of MPs in the park surface water and sediments ranged from 104.67-674.44 n·m-3 and 95.57-877.78 n·kg-1, respectively. There were four main shape types of MPs:fragments, fibers, films, and particles. MPs were dominated by fragments and fibers with small sizes (<1 mm). The polymers of MPs were polyethylene and polyethylene terephthalate. There were significant differences in the abundance of MPs in the water of different functional parks, and the abundance of MPs in comprehensive parks was the highest. The abundance of MPs in park water was closely related to the function of the park and the number of people entering the park. The pollution risk of MPs in the surface water of Guilin parks was low, whereas the pollution risk of MPs in sediments was relatively high. The results of this study indicated that tourism was an important source of MPs pollution in the water of Guilin City parks. The pollution risk of MPs in the water of Guilin City parks was mild. However, the pollution risk of MPs accumulated in small freshwater waters of urban parks requires continued attention.

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

Microplastics (MPs) pollution is considered as a globally pervasive threat to aquatic ecosystems and many studies reported this pollution in different aquatic ecosystems. However, studies on MPs pollution in wetlands are still scarce. Therefore, the aim of present study was to investigate the presence of MPs in the surface water, sediment and different fish species of Amir-Kalayeh wetland, Northern Ian. Surface water and sediment samples were collected from six stations during June to July 2022. Moreover, the gills and gastrointestinal tract (GIT) of 54 fish specimens belonging to four species including Cyprinus carpio, Tinca tinca, Esox lucius and Silurus glanis were analysed. MPs were detected in all samples with an average of 2.15 ± 1.98 items/m3 for surface water, 51.66 ± 32.20 items/kg dry weight for sediments, 0.17 ± 0.17 items/individual for fish GIT and 0.12 ± 0.12 items/individual for fish gills. There was no significant relationship between MPs abundance in surface waters and sediments as well as between MPs abundance in environmental matrices and fish (P > 0.0.5). In terms of feeding habit, no significant differences were observed between the number of MPs found in omnivorous and carnivorous fish species (P > 0.05). Moreover, no significant relationship was detected between the MPs abundance in fish tissues and body size (P > 0.05). MPs were mainly fibers, mostly transparent, and in a range size of 70-5000 µm. The dominant MPs type was nylon in all samples. This study will help increase our knowledge about MPs pollution in inland freshwater systems and suggests that management policies take essential steps to reduce this insidious problem in freshwater ecosystems.

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.

Unravelling land-based discharge of microplastics in River Basantar of Jammu & Kashmir, India: Understanding sinking behaviors and risk assessments.

Microplastic (MP) pollution is now a global critical issue and has been the subject of considerable worry for multiple various types of habitats, notably in lagoons which are coastal areas connected to the ocean. MPs are of concern, particularly because floating MP in surface water can be ingested by a number of marine organisms. There are several lagoons along Southeast Asia's coastline, but Songkhla Lagoon is Thailand's only exit with a rich biodiversity. To date, there has been little research undertaken on MP in this lagoon, so there is a pressing need to learn more about the presence of MP in the lagoon's water. We investigate MPs in the surface water of Songkhla Lagoon, Thailand. Sampling took place at ten stations in the lagoon during the wet season in December 2022 and the dry season in February 2023. Samples were digested with hydrogen peroxide to remove organic matter followed by density separation using saturated sodium chloride. MPs were visually examined under a stereo microscope to describe and determine the shape, size, and color. Polymer type was identified using a micro Fourier transform infrared (FTIR) spectrometer. Moreover, the in-situ of water quality of the surface water was measured using a multi-parameter probe. A Mann-Whitney U test was performed to investigate the variations in MP levels and water quality parameters between the wet and dry seasons. Correlation analysis (Spearman rho) was used to determine the significance of correlations between MP and water quality (p < 0.05). MPs were detected at all ten of the sites sampled. The most abundant MPs were small size class (<500 µm, primarily consisting of fibers). Five types of polymers were seen in surface water, including polyethylene terephthalate, rayon, polypropylene, polyester, and poly (ethylene:propylene). Rayon and polyester were the dominant polymers. Additionally, the most dominant color of MPs in the wet and dry season was black and blue, respectively. The mean contents of MPs in the wet and dry season were 0.43 ± 0.18 and 0.34 ± 0.08 items/L, respectively. The Mann-Whitney U test suggested a significant difference between water quality in the wet and dry seasons (p < 0.05). Correlation analysis (Spearman rho) indicated a negative significant difference relationship between the MPs and the values of total dissolved solid (TDS) in the wet season (r = -0.821, p = <0.05), revealing that the large amounts of MPs may possibly be dispersed within surface water bodies with low TDS concentrations. Based on the overall findings, MP pollution in the surface water of the lagoon is not found to be influenced by the seasonal context. Rivers flowing into the lagoon, especially the U-Taphao River, may be a principal pathway contributing to increased MP pollution loading in the lagoon. The results can be used as baseline data to undertake further research work relevant to sources, fates, distribution, and impacts of MPs in other coastal lagoons.

Bangladesh is a deltaic country in Asia, and its riverine systems ultimately drain into the Bay of Bengal. Plastic is a severe environmental issue for coastal-marine ecosystems due to the indiscriminate usage and discarding of plastic items in the upstream river that eventually find their route into the Bay of Bengal. Microplastics (MPs)are widespread pollutants in almost all environmental compartments, including aquatic environments. This study aimed to quantify and understand the distribution of microplastics in surface water and sediments of the river Karnaphuli, a tidal confluence river adjacent to the Chattogram seaport city of Bangladesh, a highly inhabited and industrial area on the southeast coast of the Bay of Bengal. A manta trawl net (300-µm mesh size) was used to collect surface water samples, while an Ekman dredge was used to collect sediment samples. The concentrations of microplastics in the surface water of the river Karnaphuli during late monsoon, winter, and early summer were recorded to be 120,111.11, 152,222.22, and 164,444.44 items/km2, respectively, while in sediments, those were recorded to be 103.83, 137.50, and 103.67 items/kg, respectively. A higher abundance of microplastics was observed in downstream surface water (228,888.88 items/km2) and sediments (164.17 items/kg). Smaller sizes (0.3 to 0.5mm) of microplastics were predominant, fibers or threads were the frequent types, and black was the most common color in the river Karnaphuli. The Fourier transform infrared analysis revealed that polyethylene terephthalate (surface water: 22%, sediments: 19%), polyamide (surface water: 15%, sediments: 13%), polyethylene (surface water: 12%, sediments: 18%), polystyrene (surface water: 13%, sediments: 11%), and alkyd resin (surface water: 13%, sediments: 10%) were the most prevalent polymers in the river Karnaphuli. Moreover, there was a moderate positive correlation between MPs abundance in surface water and sediments. Therefore, improved long-term research (in different seasons with horizontal and vertical monitoring) is necessary in order to accurately determine the flux of microplastics from the river Karnaphuli to the Bay of Bengal.

Rivers are major sources of marine microplastics. To investigate the influence of building use on river microplastic pollution, this study focused on the Chongqing section of the main stream of the Yangtze River. Surface water and sediment microplastic samples were collected and analyzed alongside building use data to explore the relationship between microplastic abundance and building use at different spatial scales. The results showed that: (1) The abundance of microplastics in surface water and sediment in the Chongqing section of the Yangtze River exhibited an inverse distribution pattern. In the upper reaches, the central urban area of Chongqing showed significantly higher microplastic levels in surface water (6,811 ± 3,101 n/m ³) compared to the lower reaches, confirming the direct input effect of high-intensity human activities. The accumulation of microplastics in sediment was greater in the northeastern section of Chongqing compared to the lower reaches (89.6 ± 69 vs. 45.4 ± 28 n/kg), indicating a hydrodynamic-driven sedimentation lag effect. (2) The influence of building use on microplastic abundance in surface water was significantly scale-dependent. Industrial buildings within a 2 km buffer zone explained up to 61.16% of the observed variance, suggesting cross-medium migration through atmospheric sedimentation and sewage pipe network. (3) Compared to land use types, building uses dominate the abundance distribution of microplastics in surface water at larger buffer radius (1–2 km), indicating that high-intensity human activities have a greater impact on spatial differentiation of microplastic pollution. It is recommended to implement hierarchical control measures along the Chongqing section of the Yangtze River. A 2-km ecological buffer zone is set up in industrial agglomeration areas to strictly supervise wastewater discharge from plastic products enterprises. Rainwater bioretention facilities are built within 1 km of densely populated areas to intercept microplastics from domestic sources, such as laundry fibers. This study explores the mechanism by which building use affects river microplastic pollution, providing valuable insights for microplastics control in large river basins worldwide.

Effects of irrigation on the fate of microplastics in typical agricultural soil and freshwater environments in the upper irrigation area of the Yellow River

Occurrence and risk assessment of microplastics in surface water, sediment, and biota of Surma River, Bangladesh.

Rivers and lakes are important channels for the migration, transformation, and transportation of microplastics （MPs） pollution from land sources into the sea. A large number of studies have investigated the pollution characteristics of MPs in different watersheds, but little to none have considered the driving factors for spatial distribution based on network analysis. In this study, Taihu Lake, Taipu River, and Huangpu River in the Yangtze River Delta were selected as the target area. Microplastics were analyzed based on field sampling, stereomicroscopy, and Fourier transform infrared spectroscopy. According to the results, MPs were 100% detected at all sampling sites. The abundance of MPs in the surface water of Taihu Lake [（7 076±1 886） n·m-3] was significantly higher than that of the Taipu River [（4 400±2 839） n·m-3] and the Huangpu River [（2 800±1 315） n·m-3], indicating a significant spatial distribution difference. The particle size of MPs was mainly distributed in the range of 0.1-0.5 mm, with transparent, black color, and fibers as the main MPs. Polyethylene terephthalate （PET）, polystyrene （PS）, and polyamide （PA） were the major contributors of polymers, accounting for 59.5%, 10.4%, and 8.67%, respectively. Correlation analysis showed that the MPs abundance was significantly positively correlated with total nitrogen （TN）, Co （R=0.436,P&lt;0.05）, and Cd （R=0.478,P&lt;0.05）, whereas they were negatively correlated with Cu （R=-0.456,P&lt;0.05）. The MPs abundance was also significantly negatively correlated with the distance from sampling points to the factory area （R=-0.796, P&lt;0.001）. Industrial point source emissions played an important role in the migration and occurrence of MPs. The co-occurrence patterns of MPs, metal elements, and water quality index were explored based on network analysis. TN and PS were the core influencing factors. Compared with other studies in the Yangtze River Delta, the risk pollution load index of surface water MPs in the watershed was 1&lt;PLIZONE&lt;2, which was characterized as light pollution. The overall ecological risk of MPs in the surface water of the research basin was relatively low.

Microplastic pollution in surface water from east coastal areas of Guangdong, South China and preliminary study on microplastics biomonitoring using two marine fish