Release Of Microplastics Research Articles

Assessment of microplastics release from polyester fabrics: The impact of different washing conditions

Synthetic fibers account for approximately 60% of the total global fiber production, and polyester (PET) and polyamide (PA) dominate. Synthetic fabrics are now widely used in clothing, upholstery, carpets and other such materials. Textiles based on these materials have the potential to release microplastics (<5 mm in size) into the environment during production and cleaning actions. These particles are released in sewage effluents, as washing machine filters and wastewater treatment plants are not specifically designed to retain them and represent an environmental pollution that continuously increases the scientific and societal concern about their effects on marine biota and ecosystems. This study was focused on the determination of the amount of microfibers release from 100% polyester fabrics, in different washing conditions (programs and temperatures), comparing the use of detergent alone vs detergent with a stain remover. Microplastics released were characterized and quantified with gravimetric analysis, different microscopic, spectroscopic and thermal techniques. Tests were carried out in replicates to assess the data reproducibility and to show statistical differences between washing conditions.

Microplastic pollution in a stormwater floating treatment wetland: Detection of tyre particles in sediment

Synthetic rubber particles released from car tyres are expected to be an important type of microplastics in the environment, with road runoff and stormwater likely to transport tyre particles to the aquatic environment. Stormwater treatment wetlands are one of the key methods for treating road runoff and stormwater, but the presence and concentration of synthetic rubber microplastics from tyre particles in wetlands are largely unknown. In addition, constructed floating wetlands can be built using recycled PET plastic bottles, raising concerns about potential release of microplastics to the environment. In this study, we measured the concentrations of microplastics in water and sediment from the inlet and outlet of a stormwater floating treatment wetland on Queensland's Gold Coast. An average of 0.9 ± 0.3 and 4.0 ± 2.4 microplastic particles/L were detected in the water phase in the inlet and outlet samples, respectively. The sediment contained an average of 595 ± 120 and 320 ± 42 microplastic particles/kg dry sediment in inlet and outlet sediments, respectively. Between 15 and 38% of microplastics in the sediment were identified by FTIR as synthetic rubber-carbon filled particles, most likely derived from car tyres. The presence of synthetic rubber microplastics confirms that tyres can contribute to microplastic pollution in stormwater, with road runoff likely to be an important pathway. No microplastics with the same characteristics and polymer composition as the floating wetland construction material were detected in the water and sediment samples, indicating that the microplastics in the water and sediment detected here did not originate from the floating wetland's material. However, further investigation of older treatment wetlands is required to better understand the potential role of floating treatment wetlands as a source of microplastics.

Dynamic probabilistic material flow analysis of rubber release from tires into the environment

The presence of microplastics in the environment is currently receiving a lot of attention. Rubber particles from tire wear have been estimated in several mass emission inventories to be a major contributor to the total microplastic release. This work used dynamic probabilistic material flow analysis to quantify the flows of rubber particles from tires to roads and further onto soils and surface waters of Switzerland. The model considered the whole life-cycle of tires from import over the use phase to the end-of-life and the re-use of scrap tires. Uncertainties of model parameters and data variability were considered by using a probabilistic approach. Mass flows onto soils and through road drainage by both uncontrolled dispersal and engineered systems are considered. In addition, the release of rubber from artificial turfs was included. The accumulation of rubber particles in the environment was quantified over the time frame from 1988 to 2018. The results show that in 2018, 1.29 ± 0.45 kg/capita of rubber was emitted from tire wear (97%) and rubber granules (3%). Street cleaning and waste water treatment removed around 26% of this rubber mass before finally reaching the receiving environmental compartment, resulting in an effective input of 0.96 ± 0.35 kg/capita of rubber in 2018 into the natural environment. Most of this mass (74%) was deposited on roadside soils (up to 5 m distance from road), 22% flowed into surface waters and the remaining part (4%) was emitted to soils. The dynamic modeling showed an increase of the input into the environment by about 10% from 1990 to 2018. The ban of sewage sludge application on soils resulted in a marked decrease in the amount transferred to soils after the year 2000. In total, 219 ± 22 ktonnes of rubber particles have accumulated in the environment since 1988 in Switzerland.

A Chemical Time Bomb: Future Risks of Microplastics

Despite the controversy, the ecological risk of microplastics research has increased sharply from only one in 1966 to 495 in 2018, according to Web of Science with microplastics as keyword. To date, an upward trend of global microplastics mass emission was confirmed by many environmental scientists. The ocean is the ultimate destination of land-based microplastics sources; therefore, most of efforts were concentrated on microplastics in aquatic environment. In this brief article, the global release of microplastics and flux into the ocean in the recent decade were estimated roughly. The plastics fragmentation in the marine environment only accounted for 22% of total microplastics release (assuming defined emission rate per capita and fragmentation rate of plastics). Future research is needed for microplastics generation and retention in the terrestrial system, especially indoor environments. The accumulated microplastics over the environmental self-purification capacity certainly increases stress for the marine, freshwater and terrestrial ecosystem.

Assessment of microplastic pollution: occurrence and characterisation in Vesij\xe4rvi lake and Pikku Vesij\xe4rvi pond, Finland

In the last few years, several studies have investigated microplastics (MPs) in marine ecosystems, but data monitoring and assessing the occurrence in freshwater environments are still scarce. The present study aims to investigate the occurrence, distribution, and chemical composition of MP pollution in Vesijärvi lake and Pikku Vesijärvi pond close to the city of Lahti (Finland) in winter. Sediment, snow, and ice core samples were collected near the shore of these two aquatic systems. MPs were analysed and identified by a non-destructive method using Fourier transform infrared spectroscopy (FTIR) 2D imaging. The mean concentrations of MPs detected in sediment, snow, and ice samples were 395.5 ± 90.7 MPs/kg, 117.1 ± 18.4 MPs/L, and 7.8 ± 1.2 MPs/L, respectively. FTIR results showed the predominant abundance of microplastics, such as polyamides (up to 53.3%), polyethylene and polypropylene (up to 17.1%), and natural fragments such as cellulose (up to 45.8%) and wool (up 18.8%) in the same size range. The potential release of MPs arising from stormwaters and sport and recreational activities was evidenced.

Removal of &gt;10 µm Microplastic Particles from Treated Wastewater by a Disc Filter

In this paper, we evaluate the performance of a disc filter that retains microplastic (MP) particles from treated wastewater. A focal plane array-based Fourier transform infrared imaging technique enabled MP quantification and an in-house-built software (MPhunter) facilitated automatic analysis of the obtained infrared spectra. The disc filter retained 89.7% of particles, and 75.6% of their mass. This removal efficiency is comparable to removal rates reported by previous studies. However, the presence of an unexpectedly large number of MP particles whose size substantially exceeded the pore size of the disc filter suggests that particles could either bypass or pass through the filter mesh, somewhat diminishing the performance of the filter. The concentration of MPs in the effluent was 3 MP/L, corresponding to an estimated mass concentration of 0.31 µg/L. The annual MP discharge from the studied WWTP after the disc filter was estimated to be 1.1 kg in 2017. It was hence not a significant contributor to MP emissions in Denmark. Although the operation of the disc filter seems to have been disturbed, it nonetheless achieved a high MP removal rate. Therefore, we conclude that it is a suitable technology to decrease the concentration of discharged MPs in wastewater effluents.

Does mechanical stress cause microplastic release from plastic water bottles?

Plastic particle ingestion has become of concern as a possible threat to human health. Previous works have already explored the presence of microplastic (MP) in bottled drinking water as a source of MP intake. Here, we consider the release of MP particles from single-use PET mineral water bottles upon exposure to mechanical stress utilizing SEM plus EDS, which allows the implementation of morphological and elemental analysis of the plastic material surface and quantification of particle concentrations in sample water. The aim of this study was to better evaluate the sources of MP intake from plastic bottles, especially considering the effect of daily use on these bottles such as the abrasion of the plastic material. For that, we analysed MP release of PET bottlenecks and HDPE caps on their surfaces after a series of bottle openings/closings (1 x, 10 x, 100 x). Furthermore, we investigated, if the inner surface of the PET bottles released MPs, counted particle increase of the water and identified MPs in the PET bottled water after exposing the bottles to mechanical stress (squeezing treatment; none, 1 min, 10 min). The results showed a considerable increase of MP particle occurrence on the surface of PET and HDPE material (bottlenecks and caps) after opening and closing the bottles. After 100 times the effect was impressive, especially on caps. Moreover, great differences exist in cap abrasion between brands which uncovers a discrepancy in plastic behavior of brands. Interestingly, particle concentrations in the bottled mineral water did not significantly increase after exposure to mechanical stress (squeezing treatment). The morphological analysis of the inner wall surface of the bottles supported this observation, as no stress cracks could be detected after the treatment, implying that the bottles itself are not a consistent source of MP particles after this extent of mechanical stress. However, chances of MP ingestion by humans increase with frequent use of the same single-use plastic bottle, though only from the bottleneck-cap system.

Mechanical formation of micro- and nano-plastic materials for environmental studies in agricultural ecosystems

Release of microplastics (MPs) and nanoplastics (NPs) into agricultural fields is of great concern due to their reported ecotoxicity to organisms that provide beneficial service to the soil such as earthworms, and the potential ability of MPs and NPs to enter the food chain. Most fundamental studies of the fate and transport of plastic particulates in terrestrial environments employ idealized MP materials as models, such as monodisperse polystyrene spheres. In contrast, plastics that reside in agricultural soils consist of polydisperse fragments resulting from degraded films employed in agriculture. There exists a need for more representative materials in fundamental studies of the fate, transport, and ecotoxicity of MPs and NPs in soil ecosystems. The objective of this study was therefore to develop a procedure to produce MPs and NPs from agricultural plastics (a mulch film prepared biodegradable polymer polybutyrate adipate-co-terephthalate (PBAT) and low-density PE [LDPE]), and to characterize the resultant materials. Soaking of PBAT films under cryogenic conditions promoted embrittlement, similar to what occurs through environmental weathering. LDPE and cryogenically-treated PBAT underwent mechanical milling followed by sieve fractionation into MP fractions of 840 μm, 250 μm, 106 μm, and 45 μm. The 106 μm fraction was subjected to wet grinding to produce NPs of average particle size 366.0 nm and 389.4 nm for PBAT and LDPE, respectively. A two-parameter Weibull model described the MPs' particle size distributions, while NPs possessed bimodal distributions. Size reduction did not produce any changes in the chemical properties of the plastics, except for slight depolymerization and an increase of crystallinity resulting from cryogenic treatment. This study suggests that MPs form from cutting and high-impact mechanical degradation as would occur during the tillage into soil, and that NPs form from the MP fragments in regions of relative weakness that possess lower molecular weight polymers and crystallinity.

Can the input of biocides and polymeric substances from antifouling paints into the sea be reduced by the use of non-toxic hard coatings?

Antifouling coatings are used to protect boat hulls from fouling organisms. The paints are designed to release biocides and by this prevent fouling organisms to attach. Until now the simultaneous release of the bulk plastic material has been over-looked. In this study the amount of antifouling paints on ships and leisure boats in Scandinavian countries and Germany has been compared and a calculation of the release of micro plastics has been performed. The result shows that use of a biocide-free hard coating will completely reduce outlet of biocides and the input of polymers will dramatically be reduced from at the most 5% in comparison to traditional paints where the release rate of plastics is estimated to be 70–85%. The advantage for the boat owners will be large since the hard maintenance work will be reduced, release of micro plastics will be low and thus lead to an improved environment.

Novel finishing treatments of polyamide fabrics by electrofluidodynamic process to reduce microplastic release during washings

Washing processes of synthetic clothes are considered the main source of microplastic pollution in the oceans, as during washing, microfibres are released and cannot be completely blocked by wastewater treatments plants, thus reaching the marine ecosystems. The development of mitigation approaches is strongly needed to prevent the impact of microplastics on marine environments. With the aim to protect the fabrics during the washing processes and then reduce the release of microfibres, in this work, new finishing treatments of polyamide fabrics were performed by an ElectroFluidoDynamic (EFD) method. This approach was used to obtain homogeneous coatings of biodegradable polymers, namely poly (lactic acid) and poly (butylene succinate-co-butylene adipate), on polyamide surface, without affecting the fabric hand and wettability. The treatments were very effective, able to significantly reduce the amount of microfibres released during washing tests, proving to be a promising application to mitigate microplastic pollution.

The contribution of washing processes of synthetic clothes to microplastic pollution

Microplastic pollution caused by washing processes of synthetic textiles has recently been assessed as the main source of primary microplastics in the oceans. Therefore, understanding the effective contribution of the washing process of synthetic clothes to this environmental problem, is of great importance. In this study, wash trials at real scale were performed on commercial clothes by using a household washing machine in order to gain reliable data about the release of microplastics, and to identify possible influences of textile characteristics on the release. The wastewater was collected and filtered through subsequent filters with decreasing porosity, and the amount and dimensions of microfibres were determined. Microfibre release was analysed in relation to the nature and characteristics of the washed clothes. Results showed that microfibres released during washing range from 124 to 308 mg for kg of washed fabric depending from the type of washed garment that corresponds to a number of microfibres ranging from 640,000 to 1,500,000. Some textile characteristics, such as the type of fibres constituting the yarns and their twist, influenced the release of microfibres during washing. A great amount of microfibres of cellulosic nature was also released during washing of clothes made with a blend of polyester/cellulose. Finally the most abundant fraction of microfibres shed was retained by filters with pore size of 60 µm, presenting an average length of 360–660 μm and an average diameter of 12–16 μm, indicating dimensions that could pass through wastewater treatment plants and pose a threat for marine organisms.

Exposure to microplastics (

The uncontrolled introduction into the environment of plastic polymers have caused the dispersion of plastic fragments, known as Microplastics (MPs), that represent an important topic for public health. This study was the first to investigate the cause of the release of MPs in mineral waters and to estimate the concentration of MPs smaller than 10 μm both in number of particles and in mass unit. This study was carried out using a patent method regarding the extraction and analysis of MPs in more kind of matrix. Therefore, aims of this study were a) to assess the number of MPs with diameters of between 0.5 and 10 μm in mineral waters contained in plastic bottles, b) to evaluate if the physical-chemical properties of mineral waters and bottle quality could influence the release of MPs and, finally, c) to estimate the human daily exposure to MPs due to mineral water consumption.The Mps were found in every sample. The main concentration of MPs was 656.8 μg/L ± 632.9 or 5.42E+07 p/L ± 1.95E+07. The main diameter of detected MPs was 2.44 μm ± 0.66 (where p/L, where p was the number of MPs). The Estimated Daily Intake (EDI) for adults and children were 1,531,524 p/kg/body-weight/day corresponding to 40.1 μg/kg/body-weight/day and 3,350,208 p/kg/body-weight/day corresponding to 87.8 μg/kg/body-weight/day, respectively.The number of MPs contamination in bottled mineral waters was strongly correlated to the pH of waters and to plastic density of bottle. Otherwise, micrograms of MPs per liter and the MPs diameters were strongly affected by plastic thickness. The most mineral water brand contaminated by MPs was the one whose bottles were made from poor quality plastic.In absence of reference values, it was no possible carried out a risk assessment for MPs exposure. It is fundamental to establish the reference method of analysis to monitoring every source of human intake.

On the Importance of Sanitary Sewer Overflow on the Total Discharge of Microplastics from Sewage Water

The paper provides an investigation and understanding of the significance of various wastewater flows on microplastics retainment and emission to the environment. WWTPs and sewer overflows as an important pathway of microplastics to the environment are assessed by considering the removal of microplastics in WWTPs with different treatment processes and several sewer overflow types and their contribution to microplastic loads to recipients. On the example of the Baltic Sea basin, presented results indicate a considerable discharge of microplastic from WWTPs despite the relatively good overall removal efficiency. Results show that the discharge of microplastics from sewer overflows can be in the same magnitude as from treated wastewater although the total flow is much lower than that of treated wastewater. Sewer overflow events frequently occur and are expected to increase due to climate change and urbanization, unless infrastructure is adapted. At the same time, sewer overflows are often neglected in conventional wastewater handling.

The fate of microplastics in an Italian Wastewater Treatment Plant

The emerged threat of microplastics (MPs) in aquatic ecosystems is posing a new challenges in environmental management, in particular the civil Wastewater Treatment Plants (WWTPs) which can act both as collectors of MPs from anthropic use and as a source to natural environments. In this study, MP fate was investigated in one of the biggest WWTPs of Northern Italy, built at the beginning of the 2000s and which serves a population equivalent of about 1,200,000, by evaluating their presence at the inlet (IN), the removal efficiency after the settler (SET) and at the outlet (OUT), and their transfer to sludge. Samples were collected in three days of a week and plastic debris was characterized in terms of shape, size and polymer composition using the Fourier Transform Infrared Microscope System (μFT-IR). The number of detected MPs was 2.5 ± 0.3 MPs/L in the IN, 0.9 ± 0.3 MPs/L after the SET and 0.4 ± 0.1 MPs/L in the OUT, indicating a total removal efficiency of 84%. However, considering that this WWTP treats about 400,000,000 L wastewaters/day, the potential release of MPs to the receiving aquatic system would be approximately 160,000,000 MPs/day, mainly polyesters (35%) and polyamide (17%). Furthermore, a great amount of MPs removed from wastewater was detected in the recycled activated sludge, with 113 ± 57 MPs/g sludge dry weight, corresponding to about 3,400,000,000 MPs deposited in the 30 tons of sludge daily produced by this WWTP. Given the possible re-use of WWTP sludge in fertilizers for agriculture, our results highlight that WWTPs could represent a potential source of MPs also to agroecosystems.

The effects of environmental conditions on the enrichment of antibiotics on microplastics in simulated natural water column

Concerns regarding the release of microplastics (MPs) into the environment led us to explore the relationship between the different environmental factors and physicochemical properties of MPs, as well as the change of interaction between MPs and organic pollutants. In this study, the effects of environmental factors (ageing conditions), such as pH, temperature, ionic strength, ageing time, and humic acid (HA) concentration, on the characteristics of MPs and their adsorption toward tetracycline (TC) were systematically investigated. The results showed that ageing factors such as pH, ionic strength, and temperature were found to have little impact on the adsorptive capacity of MPs for TC. However, MPs aged in HA solution exhibited a significant decreased adsorptive capacity for TC. HA, which has numerous functional groups, can cover the surface of MPs and change their hydrophobicity, thereby reducing the adsorption affinity to TC. The electrostatic repulsion between adsorbed HA and TC molecules may also decrease the adsorption of TC. In addition, the competing effect of HA for adsorption sites on the surface of MPs further reduces the adsorption of TC. The data presented in this work provide useful information for understanding the transfer of antibiotics by aged MPs, which is of fundamental importance to assess the environmental impact of MPs.

Wastewater treatment plants as a source of microplastics in river catchments

It is now well established that the oceans contain significant accumulations of plastic debris but only very recently have studies began to look at sources of microplastics (MPs) in river catchments. This work measured MPs up- and downstream of six wastewater treatment plants (WWTPs) in different catchments with varying characteristics and found that all led to an increase in MPs in rivers. Nevertheless, the data collected indicated that there were other important sources of MPs in the catchments studied and that these may include atmospheric deposition, agricultural land to which sewage sludge has been applied, and diffuse release of secondary MPs following the breakdown of larger plastic items. MPs were comprised mainly of fibres, fragments, and flakes with pellets and beads only dominating at one site. Variation in MP pollution occurred over time and this difference was greater at some sites than others. A key research need is the further study of MP sources in river catchments to facilitate management efforts to reduce their presence in freshwater and marine environments.

Arctic sea ice is an important temporal sink and means of transport for microplastic

Microplastics (MP) are recognized as a growing environmental hazard and have been identified as far as the remote Polar Regions, with particularly high concentrations of microplastics in sea ice. Little is known regarding the horizontal variability of MP within sea ice and how the underlying water body affects MP composition during sea ice growth. Here we show that sea ice MP has no uniform polymer composition and that, depending on the growth region and drift paths of the sea ice, unique MP patterns can be observed in different sea ice horizons. Thus even in remote regions such as the Arctic Ocean, certain MP indicate the presence of localized sources. Increasing exploitation of Arctic resources will likely lead to a higher MP load in the Arctic sea ice and will enhance the release of MP in the areas of strong seasonal sea ice melt and the outflow gateways.

Impact of water chemistry on surface charge and aggregation of polystyrene microspheres suspensions

The discharge of microplastics into aquatic environment poses the potential threat to the hydrocoles and human health. The fate and transport of microplastics in aqueous solutions are significantly influenced by water chemistry. In this study, the effect of water chemistry (i.e., pH, foreign salts and humic acid) on the surface charge and aggregation of polystyrene microsphere in aqueous solutions was conducted by batch, zeta potentials, hydrodynamic diameters, FT-IR and XPS analysis. Compared to Na+ and K+, the lower negative zeta potentials and larger hydrodynamic diameters of polystyrene microspheres after introduction of Mg2+ were observed within a wide range of pH (2.0–11.0) and ionic strength (IS, 0.01–500mmol/L). No effect of Cl−, HCO3– and SO42− on the zeta potentials and hydrodynamic diameters of polystyrene microspheres was observed at low IS concentrations (<5mmol/L), whereas the zeta potentials and hydrodynamic diameters of polystyrene microspheres after addition of SO42− were higher than that of Cl− and HCO3– at high IS concentrations (>10mmol/L). The zeta potentials of polystyrene microspheres after HA addition were decreased at pH2.0–11.0, whereas the lower hydrodynamic diameters were observed at pH<4.0. According to FT-IR and XPS analysis, the change in surface properties of polystyrene microspheres after addition of hydrated Mg2+ and HA was attributed to surface electrostatic and/or steric repulsions. These investigations are crucial for understanding the effect of water chemistry on colloidal stability of microplastics in aquatic environment.

Evaluation of microplastic release caused by textile washing processes of synthetic fabrics.

A new and more alarming source of marine contamination has been recently identified in micro and nanosized plastic fragments. Microplastics are difficult to see with the naked eye and to biodegrade in marine environment, representing a problem since they can be ingested by plankton or other marine organisms, potentially entering the food web. An important source of microplastics appears to be through sewage contaminated by synthetic fibres from washing clothes. Since this phenomenon still lacks of a comprehensive analysis, the objective of this contribution was to investigate the role of washing processes of synthetic textiles on microplastic release. In particular, an analytical protocol was set up, based on the filtration of the washing water of synthetic fabrics and on the analysis of the filters by scanning electron microscopy. The quantification of the microfibre shedding from three different synthetic fabric types, woven polyester, knitted polyester, and woven polypropylene, during washing trials simulating domestic conditions, was achieved and statistically analysed. The highest release of microplastics was recorded for the wash of woven polyester and this phenomenon was correlated to the fabric characteristics. Moreover, the extent of microfibre release from woven polyester fabrics due to different detergents, washing parameters and industrial washes was evaluated. The number of microfibres released from a typical 5kg wash load of polyester fabrics was estimated to be over 6,000,000 depending on the type of detergent used. The usage of a softener during washes reduces the number of microfibres released of more than 35%. The amount and size of the released microfibres confirm that they could not be totally retained by wastewater treatments plants, and potentially affect the aquatic environment.

Polyester Textiles as a Source of Microplastics from Households: A Mechanistic Study to Understand Microfiber Release During Washing.

Microplastic fibers make up a large proportion of microplastics found in the environment, especially in urban areas. There is good reason to consider synthetic textiles a major source of microplastic fibers, and it will not diminish since the use of synthetic fabrics, especially polyester, continues to increase. In this study we provide quantitative data regarding the size and mass of microplastic fibers released from synthetic (polyester) textiles during simulated home washing under controlled laboratory conditions. Consideration of fabric structure and washing conditions (use of detergents, temperature, wash duration, and sequential washings) allowed us to study the propensity of fiber shedding in a mechanistic way. Thousands of individual fibers were measured (number, length) from each wash solution to provide a robust data set on which to draw conclusions. Among all the variables tested, the use of detergent appeared to affect the total mass of fibers released the most, yet the detergent composition (liquid or powder) or overdosing of detergent did not significantly influence microplastic release. Despite different release quantities due to the addition of a surfactant (approximately 0.025 and 0.1 mg fibers/g textile washed, without and with detergent, respectively), the overall microplastic fiber length profile remained similar regardless of wash condition or fabric structure, with the vast majority of fibers ranging between 100 and 800 μm in length irrespective of wash cycle number. This indicates that the fiber staple length and/or debris encapsulated inside the fabric from the yarn spinning could be directly responsible for releasing stray fibers. This study serves as a first look toward understanding the physical properties of the textile itself to better understand the mechanisms of fiber shedding in the context of microplastic fiber release into laundry wash water.