Seasonal change of microplastics uptake in the Pacific oysters Crassostrea gigas cultured in the Yellow Sea and Bohai Sea, China

Temporal distribution of microplastics and other anthropogenic particles in four marine species from the Atlantic coast (France)

The characterization of microplastic (MP) contamination in marine species is increasing as concerns about environmental and food safety are more and more discussed. Here, we reported a quantitative and qualitative assessment of the contamination by anthropogenic particles (from visual sorting; AP) and MP (plastic-made) in the whole soft body or digestive tract of marine species. Four commercial species were studied, namely the Pacific oyster (Magallana gigas), the spiny spider crab (Maja sp.), the common sole (Solea solea) and seabass (Dicentrarchus labrax or punctatus). AP and MP uptake were studied over three to four seasons depending on the species. After tissues digestion, particles were extracted under a stereomicroscope and morphometric characteristics were reported. Then, polymers were identified by ATR-FTIR spectroscopy. Seasonal variations were mainly described in the Pacific oyster as AP uptake was lower in autumn and MP uptake was higher in spring. These variations may be linked to the reproduction and growth cycles of this species. Moreover, seabass ingestion was lower in autumn compared to winter. Contamination in spider crabs and soles showed either weak or no seasonal trends, both quantitatively and qualitatively. Overall, AP contamination in all studied species ranged from 1.17 ± 1.89 AP.ind-1 (in sole) to 4.07 ± 6.69 AP.ind-1 (in seabass) while MP contamination ranged from 0.10 ± 0.37 MP.ind-1 (in sole) to 1.09 ± 3.06 MP.ind-1 (in spider crab). Fibers were mostly reported in all species (at least 77.7%), along with cellulosic polymers (at least 43.7%). AP and MP uptake were detected in all species and at almost all seasons, with the only exception of the common sole during autumn. Therefore, this study emphasizes the ubiquity of AP and MP contamination in marine species and provides new knowledges about seasonal uptake by commercial species.

Seasonal variation in the abundance of microplastics in three commercial bivalves from Bandon Bay, Gulf of Thailand

This study investigated the abundance of microplastics in three commercial bivalves found at Bandon Bay. Spatial-temporal differences in the concentration of microplastics were evaluated during the dry and wet seasons. The results showed that the highest abundance of microplastics in oysters, blood cockles, and green mussels was observed in fishery and aquaculture areas during the dry season, with 1.42 particles/g (w/w), 1.01 particles/g (w/w) and 0.87 particles/g (w/w), respectively. Microplastics were more abundant during the dry season compared to the wet season (p < 0.05), with fibre being the predominant shape and black being the major colour of particles. Cellophane was the most common type of polymer in all bivalves. This result is an important reference for understanding the status of microplastics in three commercial bivalves during different seasons and in different human activities, which should aid in understanding the sources of microplastics in Bandon Bay.

Occurrence and accumulation of microplastics in commercial fish in the coastal waters of the Lvsi fishing ground in China

In recent years, there has been an exponential increase in the research popularity of microplastics (MPs) in offshore marine environments. However, there is still a gap in the research on the accumulation of MPs in different tissues of aquatic organisms and the trophic transfer of MPs between aquatic organisms. The common occurrence of MPs in the gills and guts of 11 species of commercial fishes was examined in the coastal waters of the Lvsi fishing ground (LSFG). The obtained results showed that >85 % of MPs existed in the gills and guts of these fish, and the abundance was 2.39 ± 1.38 pieces/fish and 2.56 ± 1.42 pieces/fish, respectively. Fibrous and blue are the most common colors and shapes of MPs, and PET is the main polymer type. At the species level, the abundance of MPs in the gills and guts of a few fishes (e.g., Larimichthys polyactis, Setipinna tenuifilis, Collichthys lucidus) decreased with increasing body length and body weight (P < 0.05). At the community level, this situation was not significant (P > 0.05). With increasing trophic level (TL), MPs tended to decrease in the gills (trophic magnification factor, TMF = 0.86) but did not significantly vary in the gut. We believe that MPs are multidimensional pollutants, and their accumulation in tissues/organs of organisms has not been accurately and qualitatively determined. To establish the relationship of MP transport and trophic transfer among water, sediments and organisms, we suggest that more efforts should be made to investigate MPs in aquatic organisms in the coastal waters of LSFG and to increase the examination of MPs in the water column and sediments. This study will help us improve our understanding of MPs pollution, and provide a good reference and basis for the management, monitoring and implementation of pollutants in marine organism of coastal water.

Spatial distribution of polystyrene nanoplastics and small microplastics in the Bohai Sea, China

Micro- and nano-plastic (MNP) pollution has attracted public concerns. Currently, most environmental researches focus on large microplastics (MPs), while small MNPs that have great impacts on marine ecosystems are rarely reported. Understanding the pollution levels and distribution patterns of small MNPs could help assess their potential impacts on the ecosystem. Polystyrene (PS) MNPs were often used as models to assess their toxicity, hence, we collected 21 sites in a Chinese sea area (the Bohai Sea) to analyze their pollution level and horizontal distribution in surface water samples, and vertical distributions in five sites with the water depth >25 m. Samples were filtered by glass membranes (1 μm) to trap MPs, which were frozen, ground, dried, and detected by pyrolysis-gas chromatography-mass spectrometry (pyGC-MS); while the nanoplastics (NPs) in the filtrate were captured with alkylated ferroferric oxide (Fe₃O₄) to form aggregates, which were separated by glass membrane (300 nm) filtration for pyGC-MS determination. Small PS MPs (1-100 μm) and NPs (<1 μm) were detected in 18 samples with the mass concentrations ranging from <0.015 to 0.41 μg/L, indicating that PS MNPs are widely present in Bohai Sea. Our study contributes to understanding the pollution levels and distribution patterns of MNPs (<100 μm) in the marine system and provides valuable data for their further risk assessment.