Microplastic particles are a global concern due to their widespread and growing threat to marine and coastal environments. To improve knowledge of microplastic pollution in China, we investigated 25 sediment samples collected with a box corer in the Southern Yellow Sea and East China Sea off the coast of China. The microplastics were extracted from sediments via density separation, after which they were observed under a microscope and characterized according to shape, color, and size, while polymer type identification was performed using micro-Fourier transform infrared spectroscopy. The abundance of microplastics in the offshore region of the Southern Yellow Sea and East China Sea was mapped. The mean concentration of microplastics at the 25 sites was 13.4 ± 0.6 particles 100 g⁻¹ dry weight (range: 6.0–24.0 particles 100 g⁻¹ dry weight). Based on the categorization according to shape, color, and size, fiber (77%) was the most abundant shape, while blue (35%) and transparent (29%) were the most prevalent colors. In addition, the dominant size of microplastics was smaller than 1000 μm which accounted for 89%. Finally, polyethylene, polyethylene terephthalate, acrylic, polyester, cellulose, and cellophane were the most abundant types of microplastics identified. Our result highlighted the presence of microplastics in offshore sediments from the Yellow Sea and East China Sea, and provided useful information for evaluating the environmental risks posed by microplastics in China.

In comparison with marine environments, the occurrence of microplastics in freshwater environments is less understood. In the present study, we investigated microplastic pollution levels during 2015 in Taihu Lake, the third largest Chinese lake located in one of the most developed areas of China. The abundance of microplastics reached 0.01 × 106–6.8 × 106 items/km2 in plankton net samples, 3.4–25.8 items/L in surface water, 11.0–234.6 items/kg dw in sediments and 0.2–12.5 items/g ww in Asian clams (Corbicula fluminea). The average abundance of microplastics was the highest in plankton net samples from the southeast area of the lake and in the sediments from the northwest area of the lake. The northwest area of the lake was the most heavily contaminated area of the lake, as indicated by chlorophyll-α and total phosphorus. The microplastics were dominated by fiber, 100–1000 μm in size and cellophane in composition. To our best knowledge, the microplastic levels measured in plankton net samples collected from Taihu Lake were the highest found in freshwater lakes worldwide. The ratio of the microplastics in clams to each sediment sample ranged from 38 to 3810 and was negatively correlated to the microplastic level in sediments. In brief, our results strongly suggest that high levels of microplastics occurred not only in water but also in organisms in Taihu Lake.

Indoor airborne microplastics fibers (MPFs) are emerging contaminants of growing concern. Nowadays, air conditioners (ACs) are widely used in indoor environments. However, little is known about their impact on the distribution of indoor MPFs. In this study, we first disclosed the prevalence of MPF contamination in filters for indoor split ACs used in living rooms, dormitories, and offices. The average density of microfibers was 1.47–21.4 × 10² items/cm², and a total 27.7–35.0% of fibers were MPFs. Of these fibers, the majority were polyester (45.3%), rayon (27.8%), and cellophane (20.1%). We further tracked the long-term accumulation of MPFs on AC filters in three types of rooms, and demonstrated that dormitories showed relatively heavy accumulation especially after running for 35–42 days. Furthermore, we found that simulative AC filters which had been lined with PET MPFs could effectively release those MPFs into indoor air, propelling them away from the ACs at varying distances. Statistical analysis showed that the estimated daily intake of MPFs (5–5000 μm length) from AC filters would increase gradually with their usage, with the intake volume reaching up to 11.2 ± 2.2–44.0 ± 8.9 items/kg-BW/day by the 70th day, although this number varied among people of different ages. Altogether, these findings suggest that AC filters can act as both a sink and a source of microplastics fibers. Therefore, AC filters should be evaluated not only for their substantial impact on the distribution of indoor airborne MPFs, but also for their role in the prevalence of the related health risks.

Microplastic ingestion by the farmed sea cucumber is undocumented. Microplastics were isolated from the sea cucumber Apostichopus japonicus that was collected from eight farms along the Bohai Sea and the Yellow Sea in China. To examine microplastic ingestion, the intestines were isolated, digested and then subjected to the floatation test. The microplastic abundance in the sediment ranged from 20 to 1040 particles kg−1 of dry sediment, while the ingested microplastics ranged from 0 to 30 particles intestine−1. After filtering the coelomic fluid, the extracted microplastics from the coelomic fluid ranged from 0 to 19 particles animal−1. Thus, we speculated that microplastics may transfer to the coelomic fluid of sea cucumber. The ingested microplastics did not correlate with the animal body weight but was site dependent, suggesting that sea cucumber may serve as sentinel for microplastic pollution monitoring in the sediment. The microplastics were identified by Fourier transform infrared micro spectroscopy, and the polymer types were mainly cellophane, polyester, and polyethylene terephthalate. This study revealed that, microplastics widely existed in sea cucumber farms, and that sea cucumbers ingest microplastics as suitable with their mouth open. Moreover, the microplastics might transfer to the coelomic fluid of the sea cucumber. Further investigations are needed to assess the chronic effect of the microplastics on the growth and physiological status of the sea cucumber.

Plastic pollution is a growing global concern. In the present study, we investigated plastic pollution in 21 species of sea fish and 6 species of freshwater fish from China. All of the species were found to ingest micro- or mesoplastics. The average abundance of microplastics varied from 1.1 to 7.2 items by individual and 0.2–17.2 items by gram. The average abundance of mesoplastics varied from 0.2 to 3.0 items by individual and 0.1–3.9 items by gram. Microplastics were abundant in 26 species, accounting for 55.9–92.3% of the total number of plastics items in each species. Thamnaconus septentrionalis contained the highest abundance of microplastics (7.2 items/individual). The average abundance of plastics in sea benthopelagic fishes was significantly higher than in freshwater benthopelagic fishes by items/individual. The plastics were dominanted by fiber in shape, transparent in color and cellophane in composition. The proportion of plastics in the stomach to the intestines showed great variation in different species, ranging from 0.5 to 1.9 by items/individual. The stomach of Harpodon nehereus and intestines of Pampus cinereus contained the highest number of plastics, (3.3) and (2.7), respectively, by items/individual. Our results suggested that plastic pollution was widespread in the investigated fish species and showed higher abundance in comparison with worldwide studies. The ingestion of plastics in fish was closely related to the habitat and gastrointestinal tract structure. We highly recommend that the entire gastrointestinal tract and digestion process be used in future investigations of plastic pollution in fish.

Microplastic (MP) pollution is an emerging problem in the marine environment and the assessment of the presence and abundance of microplastics in wild organisms is essential for risk assessment. The occurrence of microplastics in four species of barnacles at 30 sites in Hong Kong waters was investigated. The median number of microplastics ranged between 0 and 8.63 particles g⁻¹ wet weight, or 0 and 1.9 particles individual⁻¹, with fibers being the most abundant type of microplastics. The chemical composition of 152 pieces out of 606 potential microplastics was analyzed using micro-Fourier Transform Infrared Spectroscopy (μ-FTIR). Fifty-two of them were synthetic polymers, 95 natural cotton fibers and five unknowns. Eight types of polymer were identified with cellophane being the most abundant (58%). Correlation analysis was conducted between the abundance of MPs in sediments obtained in our previous study and that in individual barnacle species in this study, and a positive correlation was established for the barnacle Amphibalanus amphitrite, highlighting the potential of using this species as a bioindicator of microplastics.

This study assesses the microplastics (MPs) levels in mussels (Mytilus galloprovincialis) and seawater from a southern Mediterranean lagoon (Bizerte lagoon, Northern Tunisia) and discusses the potential effects of its consumption on human health. Polyethylene was the most abundant in mussels and seawater, followed by polypropylene and cellophane. The lowest and highest average MPs concentrations were recorded in the lagoon channel and southern area of the lagoon, respectively, for both mussels (2.6 ± 1.7–12.0 ± 1.4 items mussel⁻¹) and seawater (0.2 ± 0.1–0.7 ± 0.2 items L⁻¹). Mussels in areas highly polluted with fibers and polyethylene were found to have higher potential to ingest and/or adhere higher numbers of these particles. The annual dietary intake of MPs by Tunisians through the consumption of local mussels was estimated at 4.2 items capita⁻¹ year⁻¹. Even though MPs are not biodegraded and can be excreted by humans, their potential human health risks are discussed in this paper.

Microplastics (MPs) in mariculture environments may have an impact on mariculture and ecosystems. This study sampled the sediments in mariculture ponds and offshore areas in Qingduizi Bay during winter and summer. The abundance, characteristics, spatiotemporal distribution and pollution risk of microplastics were analyzed. The results showed that the abundance of MPs in the mariculture pond and offshore area was 49.2 ± 35.9 items·kg⁻¹ d.w. and 17.1 ± 9.9 items·kg⁻¹ d.w.; the MPs were mainly composed of transparent fibers of thickness 2000–5000 μm, with the main polymers being polyethylene terephthalate (PET) and cellophane (CP). The spatial distribution showed a downward trend from the inside to the outside, but the difference was not significant when comparing different seasons. The pollution load index (PLI) risk assessment showed that all sampling sites were at Hazard Level I. This study can provide valuable information for the risk assessment of microplastic pollution in mariculture areas.

Microplastics have been an emerging threat to marine environments and marine life. Oysters as seafood are popular worldwide, yet also a high-risk group to accumulate pollutants due to their filter-feeding nature. In this study, edible oysters were collected from Yantai, a coastal city in China, to study the uptake, accumulation and translocation of microplastics in marine life, as well as their in vivo interactions with other persistent pollutants. Microplastics were found in all of the studied oyster tissue samples with an average concentration around 4.53 items/g wet weight (24.49 items/g dry weight). Microplastics were mainly translocated and distributed in the gills and mantle of the studied oysters in the form of fibers. The detected microplastics in the oysters were mostly cellophane and polyester as identified by the micro-Fourier transform infrared spectroscope. Cellophane tends to accumulate in gills, mantle and muscle while polyester tends to accumulate in digestive glands of the studied oysters. Excessive concentrations of trace metals (30.484, 4.415, 0.395 and 181.044 μg/g dry weight of Cr, Cd, Pb and Cu, respectively) were detected in the studied oysters using inductively coupled plasma mass spectrometry. Trace metals of Cr, Mn, Ni, Cu, Zn, Cd and Pb were found to be adsorbed on the surface of microplastics isolated from the oysters. There was a correlation between the in vivo concentration of microplastics and the in vivo concentration of four trace metals: Cd, Cr, Cu and Pb, which suggests potential in vivo interactions between microplastics and trace metals. This study can help to understand the impacts of microplastics and their joint toxicity with other pollutants on marine life, especially on aquaculture seafood. This study will be an important reference for the assessment of health risks associated with consumption of edible coastal oysters in China.