Identification and distribution of microplastics in sediments in the mangrove area of Nusawiru Batukaras Pangandaran

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.

Effects of cascade dams on the occurrence and distribution of microplastics in surface sediments of Wujiang river basin, Southwestern China

Fishery activities are an important source of microplastic pollution in coastal areas but have received little attention. The Beibu Gulf, a traditional fishing ground of China and the China-Indo Peninsula, was selected in this study, and the focus was on the impacts of fishery activities on the horizontal distribution of microplastics in sediment. The results showed that the dominant contaminants (polypropylene fibers and polyethylene fibers) might originate from the abrasion of fishing gear and contributed to 61.6% of the total abundance of microplastics in surface sediment. The abundance of polypropylene fibers and polyethylene fibers exhibited a strong correlation (R2 = 0.8586, p = 0.015) with values of fishery yields of different districts, which highlighted the effects of different fishery activities on microplastic contamination in marine sediment. Microplastics could be "hidden" in deep sediment to a depth of 60 cm. The estimated storage of microplastics in deep sediment (185 tons) was 5 times that in surface sediment. The assessment of microplastic storage worldwide might be underestimated because most previous studies only examined surface sediment. The abundance distribution and size distribution of microplastics in the sediment core suggested long-term burial of microplastics in deep sediment. Bioturbation might be responsible for the vertical transport of microplastics, leading to "fresh microplastics" preservation in "old sediment".

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

Microplastic pollution in sediments from the Bohai Sea and the Yellow Sea, China

Co-occurrence of microplastics and heavy metals in a freshwater lake system in Indian Himalaya: Distribution and influencing factors

The mangrove ecosystem, due to its specialized root system, affects the distribution of sediment particles and pollutants in the water column, including microplastics. The objective of this study was to determine the influence of mangrove structure on the accumulation and distribution of microplastics in sediments associated with mangrove forests in the Colombian Pacific. For this purpose, sampling plots were established in sites with higher and lower tree densities, as well as with higher and lower anthropogenic interventions in Buenaventura and Tumaco bays. In each plot, sediment samples were collected and the structure of the mangrove forest was determined. Microplastics were extracted by density separation and each particle was counted and classified according to its morphology. Permanovas were used to evaluate spatial variations and generalized additive models (GAMs) were used to determine the influence of mangrove structure on microplastics accumulation in sediments. Buenaventura Bay had 306% more microplastics compared to Tumaco Bay; mangrove forests with higher tree density accumulated up to 104% more microplastics in sediments compared to forests with lower tree density, due to the energy reduction capacity of water that favors the retention of sediments and associated pollutants. The number of microplastics found in the present investigation [21.61 (RD 12.15) and 7.06 (RD 4.15) particles kg−1, for Buenaventura and Tumaco bays, respectively] is close to that found in forests in Iran and Indonesia [27.5 and 28.09 (SD 10.2) particles kg−1], and lower than that reported in mangrove forests in China and Brazil (15821 and 2868.5 particles kg−1).

The presence of microplastics, which was defined as small pieces of plastic less than 5 mm in size, in the aquatic environment has become a global concern these days. Once in the aquatic environment, microplastics might float in the water column or sink to the bottom sediment, depending on the particle density. This study was conducted in the coastal waters of Bengkalis Island in early 2020 with the aim to determine the occurrence and distribution of microplastics in sediment from six stations with suspected different sources of pollutant input. Sediment samples were taken using the PVC pipe at the depth of 0-10 cm, brought back to laboratory, observed the types and calculated their abundance. The results of the study showed that the highest abundance of microplastics was found at station 6 (83.33 and 26.67 particles/kg for fiber and film) and the lowest abundance was at stations 2 (30.00 particles/kg for fiber) and station 3 (10.00 particles/kg for films). The abundance of fiber type between stations was significantly different (p<0.05), but not for film type (p>0.05). The abundance of microplastics based on colour in each type showed that the highest abundance was in blue colour for fiber and white colour for film type. The abundance of microplastics in the northern part was found to be significantly (p<0.05) higher than in the southern part of Bengkalis Island which was assumed to be due to differences in oceanographic characteristics in both areas such as differences in the type and size of the sediment substrate.

Occurrence and distribution of microplastics in sediments of a man-made lake receiving reclaimed water

Microplastic distribution in large shallow lake sediments: Variations with offshore distance and implications for microbial communities.

Distribution of microplastics in benthic sediments of Qinghai Lake on the Tibetan Plateau, China

Physical and anthropogenic drivers shaping the spatial distribution of microplastics in the marine sediments of Chilean fjords

Sediment trap and net plankton samples were collected monthly for a year at three depths in a marine bay (Dabob Bay, Washington). These materials and subsamples from a sediment box core were analyzed for lignin oxidation products as well as elemental and stable carbon isotope compositions. The sediment core was compositionally uniform over its entire 50‐cm length. The elemental and lignin compositions of the sediment trap and core samples indicate nitrogen‐rich (atomic C : N ≅ 7.5) plankton‐derived organic matter mixed with vascular plant debris.At most, vascular plant debris accounts for 10% (nonwinter months) to 35% (winter months) of the total organic carbon in the upper water column (30 m) sediment trap samples and consists predominantly of gymnosperm wood along with some nonwoody gymnosperm tissues and angiosperm woods. Bulk land‐derived organic matter in Dabob Bay contains a maximum of 50% vascular plant debris and comprises an average of one‐third of the total organic carbon in the sediment trap samples and two‐thirds of the total organic carbon in the underlying sediments. Lignin in the sediment trap and core samples shows evidence (from elevated vanillic acid:vanillin ratios) of white‐rot fungal degradation before (but not after) introduction to the water column at the study site. Vascular plant debris introduced to the bay has already lost almost half of its initial bulk polysaccharide. Glucose yields are particularly low whereas rhamnose and fucose are obtained in excess of expected yields and must have additional sources.Lignin and neutral sugars together account for &lt;20% of the total organic carbon in the sediment trap and core samples. Overall, the sediments of Dabob Bay compositionally resemble the gymnosperm wood‐rich particulate material introduced to the overlying water column during winter and poorly record the input of plankton and other types of vascular plant debris during nonwinter months.

Spatial and temporal distributions of microplastics and their macroscopic relationship with algal blooms in Chaohu Lake, China