Microplastic (MP) is potentially harmful to lake ecosystems, with its uptake into the food web largely controlled by its residence time in the lake water column. Here we combine laboratory and ...virtual experiments to quantify residence times of small MP (<15 μm) in two contrasting model lakes; Lake Constance (large lake) and Esthwaite Water (a small lake). We compare MP residence times in a purely physical system with MP transport controlled by sinking and mixing to a model where, in addition to physical processes, zooplankton package MP into faecal pellets that are then egested into the water column. The laboratory experiments showed that MP settling velocities increased from ~5 × 10−6–10−3 mm s−1 for pristine MP to ~1 mm s−1 for MP embedded faeces. Modeled lake residence times for the 0.5 and 5 μm particles were >15 years in the abiotic models, while in the biotic simulations they were reduced to ~1 year. There was little difference between abiotic and biotic simulations for the 15 μm particles. The ratio of the MP zooplankton uptake velocity to the sinking velocity (v_up/vs_epi) was used to classify biological vs. physical transport pathways. For the 0.5 and 5 μm particles v_up/vs_epi was ≫1 in all cases for both lakes, while for the 15 μm MP there was a transition between biological and physical processes dominating residence times depending on zooplankton numbers. Our results suggest that packaging of small MP in faecal pellets by zooplankton will control its residence time in lakes. Moreover, the majority of small MP will cycle through organisms before reaching the sediment, increasing the likelihood of negative ecological effects and transfer in the food web.
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•Model suggests MP residence time in lakes controlled by zooplankton uptake.•MP imbedded in zooplankton faeces sink much faster than individual particles.•Lake residence times of small MP shorted from 15 years to <1 year•Small MP will cycle through the ecosystem before reaching the sediments.•Sinking also important for large particles (>15 μm)
This study assessed the ecological risk posed by microplastics in surface and subsurface seawaters in coastal, continental shelf, and deep-sea areas of South Korea. The target microplastics for risk ...assessment were specified as only non-spherical type microplastics in the size range 20–300 μm, because this type was predominantly observed in our study areas, and adverse biological effects have previously been reported. Exposure data for non-spherical microplastics were obtained from a previous study or were measured for microplastics of sizes down to 20 μm. A predicted no-effect concentration (PNEC) of 12 particles/L was derived by employing a species sensitivity distribution approach. Then the results were compared to the in situ observed concentrations at each site. The detected microplastic concentrations did not exceed the derived PNEC, i.e., the current pollution levels of fragment and fiber microplastics in the size range 20–300 μm would not pose a significant threat to the marine ecosystem in South Korea. However, predictions are that microplastic pollution will increase to 50-fold by 2100 at the current rates, and in this scenario, the microplastic concentration is expected to far exceed the derived PNEC values for marine ecosystems. It is therefore urgent to take precautionary actions to prevent a further increase in microplastic concentrations in these environments.
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•Predicted no effect concentration (PNEC) for non-spherical microplastic was derived.•The microplastic concentrations in Korean marine water was lower than PNEC.•No ecological risk in Korean saltwater environments is suspected.•The microplastic concentration is predicted to well exceed PNEC value by 2100.•Actions to prevent a further increase in microplastic concentrations should be taken.
Ecological risk assessment was conducted by matching size range and morphology of microplastics in both toxicity data and field monitoring data.
Currently, microplastics are a major challenge threatening marine environment. Given little information on their prevalence in the Persian Gulf, the present study as the first comprehensive study was ...conducted to evaluate microplastics abundance in surface waters. Neustonic samples were collected from 15 stations along the Persian Gulf. Visually separated microplastics were categorized according to their size, shape, and color. ATR-FTIR method was used to identify the composition of polymers. Microplastics were found in all sampling stations and their density varied from 1.5 × 103 to 4.6 × 104 particle.km-2 with a mean density of 1.8 × 104 particle.km-2. Fibers were the most dominant shape of microplastics (44.1%). Approximately 76% of the analyzed microplastics were polyethylene and polypropylene and the predominant colors of the microplastics were white and blue. Results of the study confirmed prevalence of microplastics in the Persian Gulf, and findings suggested a pressing need to investigate their effects on marine life and human health.
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•A comprehensive study on microplastics pollution in the surface waters of the Persian Gulf was don for the first time.•Microplastics were found in all the stations.•Fibers were the most abundance shapes of microplastics.•The most common polymer types in the samples were polyethylene and polypropylene.•The western part of the Persian Gulf polluted more than the eastern part.
Contamination of waters and soils with microplastics (MPs) is an emerging environmental issue worldwide. MPs constitute a cocktail of various additives and polymers besides adsorbing toxic heavy ...metals from the environment. This co-occurrence of MPs with heavy metals poses a threat to the health of organisms and is poorly understood. Ingestion of MPs contaminated with heavy metals may also result in subsequent transfer of heavy metals up in the food chain. MPs surfaces play a crucial role in the adsorption of heavy metals. Aged/biofouled MPs facilitate greater adsorption of metals and certain microplastic (MP) polymers adsorb some metals more specifically. External factors involved in the process of adsorption/accumulation of heavy metals are the solution pH, salinity, and the concentration of relevant heavy metals in the media. Desorption greatly depends upon pH of the external solution. This is more concerning as the guts/digestive systems of organisms have low pH which could enhance the desorption of toxic metals and making them accumulate in their bodies. The aim of this article is to discuss the abundance, distribution, adsorption, and desorption behavior of MPs for heavy metals, and their combined toxic effects on flora and fauna based on the limited research on this topic in the literature. There is an overarching need to understand the interactions of MPs with heavy metals in different ecosystems so that the extent of ecotoxic effects they pose could be assessed which would help in the environmental regulation of these pollutants.
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•Microplastics become more toxic after adsorbing heavy metals from the environment.•Certain MP polymers adsorb some heavy metals more specifically.•Adsorption depends upon aging of MPs, and pH and salinity of the media.•Desorption greatly depends upon the pH of the external solution.•MPs increase the bioaccessibility of heavy metals.
•MPs are quantified by particle number and mass using µFTIR imaging and Py-GCMS, respectively.•Low MP concentrations (0.174 MPs/L) in potable drinking water.•Detection of low MP loads in comparable ...concentrations with the two complementary techniques µFTIR and Py-GCMS.•32% of MPs were smaller than 20 µm.
While it seems indisputable that potable water contains microplastics (MP), the actual concentrations are much debated and reported numbers vary many orders of magnitude. It is difficult to pinpoint the cause of these differences, but it might be variation between waters, variation between quantification methods, and that some studies did not live up to rigorous analytical standards. Despite the urgent need to understand human exposure by drinking water, there is a lack of trustable methods generating reliable data. Essentially, proper MP assessment requires that quality assurance is in place and demonstrated, that an adequate volume of drinking water is assessed, and that differences in analytical methods are understood. This study presents a systematic and robust approach where MP down to 6.6 µm were assessed in potable water distribution systems in terms of quantity, size, shape, and material. For the first time, sub-samples were analysed by two of the most validated and complementary analytical techniques: µFTIR imaging and Py-GCMS. Both methods successfully determined low contents in drinking water. However, µFTIR and Py-GCMS identified different polymer types in samples with overall low MP content. With increasing concentration of a given polymer type, the values determined by the techniques became more comparable. Most detected MPs were smaller than 150 µm, and 32% were smaller than 20 µm. Our results indicate a potential annual uptake of less than one MP per person, suggesting that drinking potable water produced at a high-performance drinking water treatment plant represents a low risk for human health.
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Microplastic pollution is a problem of global scale, posing a threat to marine biota. To determine the current state of microplastic pollution on four popular sandy beaches of the coast of Lima, ...Peru, a sampling campaign was carried out in both intertidal and supralittoral zones. Microplastic abundance, type, size, color and distribution were recorded. The overall microplastic abundance was of the same order of magnitude as previous data obtained in Peru. Foams were the most abundant (78.3%) microplastic type. Statistical analyses revealed significant differences between sites and zones. High variability of microplastic abundance was found among adjacent beaches and zones. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed that all foams were identified as polystyrene. The present results revealed an alarming level of microplastics present on Peruvian sandy beaches, but information about the sources, local dynamics and impacts of microplastics in this region are scarce, and thus further research is needed.
•Microplastic abundance and distribution were assessed at 4 sandy beaches of Lima, Peru.•White coloured foams were the dominant microplastic type in all beaches.•FTIR analysis determined the polymer composition for every microplastic type.•Polystyrene was the most abundant microplastic.•High microplastic abundance in the intertidal zone is due to surface currents, artificial structures and styrofoam littering.
We developed a regional atmospheric transport model for microplastics (MPs, 10 μm to 5 mm in size) over Asia and the adjacent Pacific and Indian oceans, accounting for MPs’ size- and shape-dependent ...aerodynamics. The model was driven by tuned atmospheric emissions of MPs from the land and the ocean, and the simulations were evaluated against coastal (n = 19) and marine (n = 56) observations. Our tuned atmospheric emissions of MPs from Asia and the adjacent oceans were 310 Gg y–1 (1 Gg = 1 kton) and 60 Gg y–1, respectively. MP lines and fragments may be transported in the atmosphere >1000 km; MP pellets in our model mostly deposited near-source. We estimated that 1.4% of the MP mass emitted into the Asian atmosphere deposited into the oceans via atmospheric transport; the rest deposited over land. The resulting net atmospheric transported MP flux from Asia into the oceans was 3.9 Gg y–1, twice as large as a previous estimate for the riverine-transported MP flux from Asia into the oceans. The uncertainty of our simulated atmospheric MP budget was between factors of 3 and 7. Our work highlighted the impacts of the size and morphology on the aerodynamics of MPs and the importance of atmospheric transport in the source-to-sink relationship of global MP pollution.
This study was aimed to investigate the abundance and characteristics of microplastics (MP) in the sediment of Jagir estuary and Wonorejo coast, Surabaya, Indonesia. Sediment samples from 5 sites in ...the estuary and the adjacent coast were collected in replicates using Ekman dredge sampler. The MP particles were extracted using density separation method. Then the MP particles were counted and categorized according to shape, size, and color under a Zeiss Discovery V.12 stereomicroscope. Identification was done using Thermo Scientific Nicolet iS10 FTIR Spectrometer. The MP shapes comprised fiber (57%), film (36%), and fragment (7%). Abundance of the MP was highest in the Wonorejo coast sediment (590 particles/kg dry weight). The MP particles consisted of 68% large and 25% small sizes and comprised 56.7% polyester, 24.6% low-density polyethylene, and 18.8% polypropylene. The MP colors were 43% transparent, 21% black, 14% blue, 10% white, 8% red, and 4% yellow.
•Microplastic concentrations in the sediment increased toward the river mouth.•Microplastic abundance in the sediment of Wonorejo coast was higher than in Jagir estuary.•Large microplastic particles were predominant in the sediment of the estuary and the coast,•Fiber shaped microplastic of polyester type was found in highest abundance in all sampling sites
The extensive application of plastic in human life brings about microplastic (MP) pollution in the environment. Identifying the potential sources of MPs is necessary to diminish its pollution. In ...this study, the occurrence, composition and distribution of MPs in the influents and effluents from 9 domestic wastewater treatment plants (WWTPs), 5 industrial WWTPs, wastewater of 10 industrial plants, 4 livestock farms and 4 fish ponds in China were investigated. Water samples were enzymatically treated followed by digestion with hydrogen peroxide and density separation. MPs were characterized using micro-Raman spectroscopy and were categorized by shape, size and color. Results showed that MP abundance in the influents and effluents of domestic WWTPs was 18–890 and 6–26 n·L−1, respectively, with the removal efficiency ranging from 35 to 98%. The effluents of industrial WWTPs contained 6–12 n·L−1 and the levels of MPs in the wastewater of industrial plants, livestock farms and fish ponds were in the range of 8–23, 8–40 and 13–27 n·L−1, respectively. No significant differences of MP abundance were demonstrated among effluents or wastewater of different sources, indicating they all constitute sources of MP pollution. Polyethylene (PE), polypropylene (PP) and polystyrene (PS) made up almost 83% of the total MPs. Fragment and film were the most abundant shapes and the majority of MPs were smaller than 500 μm. Polymer type and shape in different sources did not vary statistically, however, there were slight differences among different sources concerning size and color of MPs. This study could fill MP data gaps regarding different sources, guide future monitoring work and policy making.
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•A wide campaign has been performed to reveal MPs in different wastewater sources.•Levels of MPs in the influents of domestic WWTPs varied from 18 to 890 n·L−1.•Abundance of MPs in effluents or wastewater from different sources was 6–40 n·L−1.•Type and shape of MPs from different wastewater did not significantly vary.•Size and color of MPs slightly differed among wastewater from different sources.
Littered plastics are partly introduced into water bodies, ultimately transporting this waste to the shores and oceans. At the shore, ultraviolet (UV) radiation (also present in other environmental ...compartments) and wave breaking cause plastics to degrade and fragment into smaller particles, called microplastics, if below 5 mm. Since these plastics’ surfaces can act as vectors for hydrophobic (toxic) chemical substances (e.g., per- and polyfluoroalkyl substances (PFAS)) and leach (toxic) chemicals into the water, the increase in the surface area through the fragmentation of plastics becomes relevant. Studies investigating different effects on the fragmentation of plastics have mostly disregarded a sufficient mechanical component for fragmentation, focusing on degradation by UV radiation. Therefore, this study investigated the impact of the mechanical fragmentation drivers, wave impact, and sediment abrasion on the fragmentation of expanded polystyrene (EPS), high-density polyethylene (PE-HD), and polyethylene terephthalate (PET) particles. In a newly designed test facility called Slosh-Box, the mentioned impacts were investigated concurrently. The results reveal that the mechanical impacts alone are sufficient for plastic fragmentation, and the test facility is suitable for fragmentation investigations. Furthermore, the increase in surface area was determined via scanning electron microscopy. For EPS, the surface area increased more than 2370-fold, while for PE-HD and PET, surface areas increased between 1 and 8.6 times. Concluding from the results, the new test facility is suitable for plastic fragmentation studies. In addition, sediment was revealed to be a relevant fragmentation driver, which should be included in every experiment investigating the fragmentation of plastic in a nearshore environment independent of other drivers like UV radiation.
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