Microplastics and non-natural cellulosic particles in Spanish bottled drinking water.

This investigation explored the presence of microplastics (MPs) and artificial cellulosic particles (ACPs) in commercial water marketed in single use 1.5 L poly(ethylene terephthalate) bottles. In this work we determined a mass concentration of 1.61 (1.10-2.88) µg/L and 1.04 (0.43-1.82) µg/L for MPs and ACPs respectively in five top-selling brands from the Spanish bottled water market. Most MPs consisted of white and transparent polyester and polyethylene particles, while most ACPs were cellulosic fibers likely originating from textiles. The median size of MPs and ACPs was 93 µm (interquartile range 76-130 µm) and 77 µm (interquartile range 60-96 µm), respectively. Particle mass size distributions were fitted to a logistic function, enabling comparisons with other studies. The estimated daily intake of MPs due to the consumption of bottled water falls within the 4-18 ng kg-1 day-1 range, meaning that exposure to plastics through bottled water probably represents a negligible risk to human health. However, it's worth noting that the concentration of plastic found was much higher than that recorded for tap water, which supports the argument in favour of municipal drinking water.

Looking beyond the obvious: The ecotoxicological impact of the leachate from fishing nets and cables in the marine mussel Mytilus galloprovincialis.

Once in the marine environment, fishing nets and cables undergo weathering, breaking down into micro and nano-size particles and leaching plastic additives, which negatively affect marine biota. This study aims to unravel the ecotoxicological impact of different concentrations of leachate obtained from abandoned or lost fishing nets and cables in the mussel Mytilus galloprovincialis under long-term exposure (28 days). Biochemical biomarkers linked to antioxidant defense system, xenobiotic biotransformation, oxidative damage, genotoxicity, and neurotoxicity were evaluated in different mussel tissues. The chemical nature of the fishing nets and cables and the chemical composition of the leachate were assessed and metals, plasticizers, UV stabilizers, flame retardants, antioxidants, dyes, flavoring agents, preservatives, intermediates and photo initiators were detected. The leachate severely affected the antioxidant and biotransformation systems in mussels' tissues. Following exposure to 1 mg·L-1 of leachate, mussels' defense system was enhanced to prevent oxidative damage. In contrast, in mussels exposed to 10 and 100 mg·L-1 of leachate, defenses failed to overcome pro-oxidant molecules, resulting in genotoxicity and oxidative damage. Principal component analysis (PCA) and Weight of Evidence (WOE) evaluation confirmed that mussels were significantly affected by the leachate being the hazard of the leachate concentrations of 10 mg·L-1 ranked as major, while 1 and 100 mg·L-1 was moderate. These results highlighted that the leachate from fishing nets and cables can be a threat to the heath of the mussel M. galloprovincialis.

Beneath the water column: Uncovering microplastic pollution in the sublittoral coastal sediments of the Canary Islands, Spain.

Marine ecosystems pollution by microplastics (MPs) is a global problem of special concern. The present study examines the prevalence and distribution of MPs and cellulosic particles in sublittoral coastal sediments of the Canary Islands archipelago (Spain). At twenty-six different locations alongside seven islands, three samples were taken parallel to the shoreline between 1 and 10 m depth (n = 78). Sediment samples were primarily digested with a H2O2 solution followed by four flotations in a saturated NaCl solution. The mean concentration obtained was 3.9 ± 1.6 items/g of dry weight. A similar distribution pattern was observed across all islands concerning particles morphology, color, size and composition: mainly colorless/translucent and blue fibers (60.0%). Additionally, fragments were also found, and to a much lesser extent microbeads, films and tangled messes. MicroFourier Transform Infrared spectroscopy analysis of 12.5% of the fibers, showed that they were mainly cellulosic (54.5%) -either natural or semisynthetic- followed by polyester (22.7%) and acrylic (4.5%). The potential correlation between particle distribution in nearshore sediments and wave intensity was also explored. This work provides the first comprehensive report on the current MPs content of the seabed of the region.

A nationwide monitoring of atmospheric microplastic deposition.

Plastic production continues to increase every year, yet it is widely acknowledged that a significant portion of this material ends up in ecosystems as microplastics (MPs). Among all the environmental compartments affected by MPs, the atmosphere remains the least well-known. Here, we conducted a one-year simultaneous monitoring of atmospheric MPs deposition in ten urban areas, each with different population sizes, economic activities, and climates. The objective was to assess the role of the atmosphere in the fate of MPs by conducting a nationwide quantification of atmospheric MP deposition. To achieve this, we deployed collectors in ten different urban areas across continental Spain and the Canary Islands. We implemented a systematic sampling methodology with rigorous quality control/quality assurance, along with particle-oriented identification and quantification of anthropogenic particle deposition, which included MPs and industrially processed natural fibres. Among the sampled MPs, polyester fibres were the most abundant, followed by acrylic polymers, polypropylene, and alkyd resins. Their equivalent sizes ranged from 22 µm to 398 µm, with a median value of 71 µm. The particle size distribution of MPs showed fewer large particles than expected from a three-dimensional fractal fragmentation pattern, which was attributed to the higher mobility of small particles, especially fibres. The atmospheric deposition rate of MPs ranged from 5.6 to 78.6 MPs m-2 day-1, with the higher values observed in densely populated areas such as Barcelona and Madrid. Additionally, we detected natural polymers, mostly cellulosic fibres with evidence of industrial processing, with a deposition rate ranging from 6.4 to 58.6 particles m-2 day-1. There was a positive correlation was found between the population of the study area and the median of atmospheric MP deposition, supporting the hypothesis that urban areas act as sources of atmospheric MPs. Our study presents a systematic methodology for monitoring atmospheric MP deposition.

Occurrence and size distribution study of microplastics in household water from different cities in continental Spain and the Canary Islands.

The purpose of this study was to investigate the occurrence of microplastics (MPs) in drinking water in Spain by comparing tap water from different locations using common sampling and identification procedures. We sampled tap water from 24 points in 8 different locations from continental Spain and the Canary Islands by means of 25 µm opening size steel filters coupled to household connections. All particles were measured and spectroscopically characterized including not only MPs but also particles consisting of natural materials with evidence of industrial processing, such as dyed natural fibres, referred insofar as artificial particles (APs). The average concentration of MPs was 12.5 ± 4.9 MPs/m3 and that of anthropogenic particles 32.2 ± 12.5 APs/m3. The main synthetic polymers detected were polyamide, polyester, and polypropylene, with lower counts of other polymers including the biopolymer poly(lactic acid). Particle size and mass distributions were parameterized by means of power law distributions, which allowed performing estimations of the concentration of smaller particles provided the same scaling parameter of the power law applies. The calculated total mass concentration of the identified MPs was 45.5 ng/L. The observed size distribution of MPs allowed an estimation for the concentration of nanoplastics (< 1 µm) well below the ng/L range; higher concentrations are not consistent with scale invariant fractal fragmentation. Our findings showed that MPs in the drinking water sampled in this work do not represent a significant way of exposure to MPs and would probably pose a negligible risk for human health.

Ageing and fragmentation of marine microplastics.

The generation of small fragments from the environmental ageing of microplastics (MPs) is still a poorly known process. This work addresses the fragmentation of MPs obtained from marine debris consisting of polyethylene and polypropylene (PE and PP in environmental mixture) and polystyrene (PS) after exposure to accelerated ageing by irradiation and mechanical stirring. Number particle size distribution in the 1-100 µm range was assessed by combining laser diffractometry with particle counts from flow cytometry. The results showed the generation of a high number of small MP particles, which reached 105-106 items/mg of plastic with most fragments <2 µm. The results showed that environmentally aged MPs give rise to a larger number of small MPs in a pattern consistent with progressive fragmentation in the three spatial dimensions. The proportion of small MPs was much higher than that found in current sampling campaigns, suggesting a severe underestimation of the environmental presence of small MPs. We also demonstrated the generation of nanoplastics (NPs) in the fraction <1 µm from irradiated runs. The results showed that the mechanism that produced nanoplastics (NPs) from MPs was irradiation, which yielded up to 1011-1013 NPs/g with particle size in the few hundreds of nm range. Our results are relevant for the assessment of fate and risk of plastic debris in the environment showing that the number of small plastic fragments produced during the ageing of MPs is much larger than expect from the extrapolation of larger size populations.

Microplastics identification and quantification in the composted Organic Fraction of Municipal Solid Waste.

Composted Organic Fraction of Municipal Solid Waste (OFMSW) is used in agricultural soils as a source of organic matter and nutrients. Besides, its use avoids landfilling or incineration following the principles of circular economy. It is well established that source separated OFMSW is suitable for compost production, but its quality depends on their content in non-compostable materials. In this work, we selected and studied the final refined compost form five OFMSW facilities over a five-month period. The plants displayed differences in collection systems, concentration on non-desired materials, treatment technology and density of served population. The presence of plastic was studied using a separation and identification process that consisted of oxidation and flotation followed by spectroscopic identification. The results showed a concentration of plastic impurities in the 10-30 items/g of dry compost range. The concentration of small fragments and fibres (equivalent diameter < 5 mm) was in the 5-20 items/g of dry weight range and were dominated by fibres (25% of all particles <500 µm). Five polymers represented 94% of the plastic items: polyethylene, polystyrene, polyester, polypropylene, polyvinyl chloride, and acrylic polymers in order of abundance. Polyethylene was more abundant in films, polystyrene in fragments, polypropylene in filaments, and fibres were dominated by polyester. Our results showed that smaller plants, with OFMSW door-to-door collection systems produced compost with less plastic of all sizes. Compost from big facilities fed by OFMSW from street bin collection displayed the highest contents of plastics. No debris from compostable bioplastics were found in any of the samples, meaning that if correctly composted their current use does not contribute to the spreading of anthropogenic pollution. Our results suggested that the use of compostable polymers and the implementation of door-to-door collection systems could reduce the concentration of plastic impurities in compost from OFMSW.

Generation of nanoplastics during the photoageing of low-density polyethylene.

In this work, we studied the hydrolytic and photochemical degradation of three low-density polyethylene (LDPE) materials, within the size range of microplastics (MP). The MPs were exposed to mechanical agitation and UV irradiation equivalent to one year of solar UVB + UVA in a stirred photoreactor. Flow cytometry was used to track the formation of small (1-25 µm) MPs by applying Mie's theory to derive the size of MP particles from scattering intensity readings. The calculation was based on a calibration with polystyrene (PS) beads. The results showed that the generation of 1-5 µm MP reached 104-105 MPs in the 1-25 µm range per gram of LDPE. ATR-FTIR and micro-FTIR measurements evidenced the formation of oxygenated moieties, namely hydroxyl, carbonyl, and carbon-oxygen bonds, which increased with irradiation time. We also found evidence of the production of a high number of nanoplastics (<1 µm, NPs). The Dynamic Light Scattering size of secondary NPs was in the hundreds of nm range and might represent up to 1010 NPs per gram of LDPE. Our results allowed the unambiguous spectroscopic assessment of the generation of NPs from LDPE under conditions simulating environmental exposure to UV irradiation and used flow cytometry for the first-time to track the formation of secondary MPs.

Honeybees as active samplers for microplastics.

Microplastics are ubiquitous and their sampling is a difficult task. Honeybees interact with the environment inside their foraging range and take pollutants with them. In this work, we demonstrated for the first time that worker bees can act as active samplers of microplastics. We collected honeybees from apiaries located in the centre of Copenhagen and from nearby semiurban and rural areas. We showed the presence of microplastics in all sampled locations mostly in the form of fragments (52%) and fibres (38%) with average equivalent diameter of 64 ± 39 µm for fibres and 234 ± 156 µm for fragments. The highest load corresponded to urban apiaries, but comparable number of microplastics was found in hives from suburban and rural areas, which can be explained by the presence of urban settlements inside the foraging range of worker bees and to the easy dispersion of small microplastics by wind. Micro-FTIR analysis confirmed the presence of thirteen synthetic polymers, the most frequently of which was polyester followed by polyethylene and polyvinyl chloride. Our results demonstrated the presence of microplastics attached to the body of the honeybees and opens a new research pathway to their use as active biosamplers for anthropogenic pollution.

Occurrence and transport of microplastics sampled within and above the planetary boundary layer.

Nowadays, there is no direct evidence about the presence of microplastics (MPs) in the atmosphere above ground level. Here, we investigated the occurrence, chemical composition, shape, and size of MPs in aircraft sampling campaigns flying within and above the planetary boundary layer (PBL). The results showed that MPs were present with concentrations ranging from 1.5 MPs m-3 above rural areas to 13.9 MPs m-3 above urban areas. MPs represented up to almost one third of the total amount of microparticles collected. Fourier Transform Infrared Spectroscopy allowed identifying seven types of MPs with the highest diversity corresponding to urban areas. Atmospheric transport and deposition simulations were performed using the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. Air mass trajectory analyses showed that MPs could be transported more than 1000 km before being deposited. This pioneer study is the first evidence of the microplastic presence above PBL and their potential long-range transport from their point of release even crossing distant borders.

First detection of microplastics in the freshwater of an Antarctic Specially Protected Area.

Microplastics have been found in all environmental compartments investigated so far, even reaching remote areas. However, their presence in Antarctic freshwaters has not been yet reported. Here, we investigated the occurrence of microplastics in a stream from an Antarctic Specially Protected Area (Byers Peninsula, Livingston Island - ASPA No. 126), which is subject to stringent environmental protection measures as a result of which it is considered a pristine international reference site for inland waters research. Our results showed the presence of three types of microplastics in a freshwater seasonal stream, namely four polyester fibers, one black and three transparent; two acrylic fibers, one transparent and one red; and two transparent polytetrafluoroethylene films. The length and width of these fibers and films were in the 400-3546 µm (average 1118 µm), and 10-1026 µm (average 199 µm) ranges respectively. The concentration of MP was 0.95 items/1000 m3 with estimated variability in the 0.47-1.43 items/1000 m3 range. This is the first report of the presence of microplastics in Antarctic freshwater with the uniqueness that it is an Antarctic Specially Protected Area, meaning that plastic pollution reached even the most remote and pristine environments in the planet.

Microplastics in sediments of artificially recharged lagoons: Case study in a Biosphere Reserve.

We studied the occurrence of microplastics in sediments of artificially and non-artificially recharged lagoons from the network of endorheic wetlands called "La Mancha Húmeda", declared Biosphere Reserve by UNESCO. The particles sampled in this study covered the 25 µm-5 mm range. Films were the dominant microplastic typology in non-artificially recharged lagoons, while fibres and fragments were more abundant in those receiving wastewater. The concentration of microplastics in sediments reached up to 24.4 ± 5.2 microplastics/g, while plastic litter counts yielded <1 particle/g in non-wastewater receiving lagoons. Eleven types of plastic were identified using Micro-Fourier Transform Infrared Spectroscopy (micro-FTIR), the most abundant being the polyolefins polyethylene and polypropylene, and polyester and acrylic fibres. The statistical analysis of FTIR spectra confirmed the similarity between samples taken from recharged lagoons and wastewater treatment plant effluents. Overall, our results showed that endorheic lagoons are very sensitive to the accumulation of persistent pollutants, which include microplastics. The recharge of lagoons with wastewater effluents to maintain water levels, even if correctly treated according to current standards, is not a sustainable practice. Due to the closed character of endorheic basins, the continuous input of wastewater led to the accumulation of microplastics in sediments of wastewater receiving lagoons up to 40 times over non-recharged lagoons.

Fibers spreading worldwide: Microplastics and other anthropogenic litter in an Arctic freshwater lake.

We investigated the presence of microplastics and other anthropogenic litter in the sediments adhered to rocks of an Arctic freshwater lake at Ny-Ålesund (Svalbard Archipelago, 78°N; 11°E). Most of the sampled microparticles were fibers (>90%). The identification of polymer types and additives was performed by combining three spectroscopic techniques, namely Raman Microscopy, Fourier-Transform Infrared microspectroscopy (µFTIR) and Synchrotron Radiation µFTIR (SR-FTIR). SR-FTIR confirmed the presence of poly(ethylene terephthalate) fibers, while RAMAN spectroscopy provided evidence of fibers containing industrial additives. Our results estimated an average concentration of 400 microparticles/m2 of rocks identified as anthropogenic litter, which included an estimation of 90 microplastics/m2 identified as polyester fibers; the rest are mostly natural fibers with evidence of anthropogenic origin. Taken together, the results proved the occurrence of anthropogenic pollutants in remote polar areas. Their probable origin is the long range atmospheric transport.

Fate of microplastics in wastewater treatment plants and their environmental dispersion with effluent and sludge.

This work studied the occurrence of microplastics in primary and secondary effluents and mixed sludge of a WWTP as well as in processed heat-dried sludge marketed as soil amendment. Sampled microparticles were divided into fragments and fibres, the latter defined as those with cylindrical shape and length to diameter ratio >3. We showed the presence of 12 different anthropogenic polymers or groups of polymers with a predominance of polyethylene, polypropylene, polyester and acrylic fibres together with an important amount of manufactured natural fibres. The smaller sampled fraction, in the 25-104 µm range, was the largest in both primary and secondary effluents. Fibres displayed lower sizes than fragments and represented less than one third of the anthropogenic particles sampled in effluents but up to 84% of heat-dried sludge. The plant showed a high efficiency (>90%) in removing microplastics from wastewater. However, the amount of anthropogenic plastics debris in the 25 µm - 50 mm range still released with the effluent amounted to 12.8 ± 6.3 particles/L, representing 300 million plastic debris per day and an approximate load of microplastics of 350 particles/m3 in the receiving Henares River. WWTP mixed sludge contained 183 ± 84 particles/g while heat-dried sludge bore 165 ± 37 particles/g. The sludge of the WWTP sampled in this work, would disseminate 8 × 1011 plastic particles per year if improperly managed. The agricultural use of sludge as soil amendment in the area of Madrid could spread up to 1013 microplastic particles in agricultural soils per year.

Occurrence and identification of microplastics along a beach in the Biosphere Reserve of Lanzarote.

This work studied the accumulation of plastic debris in a remote beach located in La Graciosa island (Chinijo archipelago, Canary Islands). Microplastics were sampled in the 1-5 mm mesh opening range. An average plastic density of 36.3 g/m2 was obtained with a large variability along the 90 m of the beach (from 8.5 g/m2 to 103.4 g/m2). Microplastic particles preferentially accumulated in the part of the beach protected by rocks. A total number of 9149 plastic particles were collected, recorded and measured, 87% of which corresponded to fragments. Clear colours and microscopic evidence of weathering corresponded to aged plastics wind-driven by the surface Canary Current. The chemical composition of plastics particles corresponded to PE (63%), PP (32%) and PS (3%). Higher PE/PP ratios were recorded in the more protected parts of the beach, suggesting preferential accumulation of more aged fragments.