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The Philippines is primarily an agricultural country in which most Filipinos depend on the health of the soil for livelihood. Plastic pollution adversely affects agriculture by degrading soil quality, fertility, and crop growth. However, the prevalence of plastic particles such as mesoplastics (>5 mm to 25 mm) and microplastics (<5 mm) in agricultural soils in the Philippines remains poorly understood. This study investigated the prevalence of mesoplastics and microplastics in agricultural soils in Iligan City, Philippines. We collected soil samples from the six sampling stations in high-elevation and low-elevation sites. Mesoplastics and microplastics were examined through manual sorting, categorized based on color, shape, and size, and identified using Fourier-transform infrared spectroscopy (FTIR). Mesoplastics were found to be more prevalent, averaging 2.22 items/kg compared to microplastics 0.83 items/kg. Mesoplastics were mainly white-colored (42%), mostly fragmented (55%), 5–10 mm in size (55%), and were predominantly polypropylene (85%). Microplastics were mainly transparent (40%), composed of fragments and film shapes(46%), and 3–4 mm (93%) in size. Polyethylene was the abundant microplastic polymer type (47%). It was observed that the low-elevation sites had a higher abundance of plastic particles, stressing the need to address local factors in tackling plastic pollution. [ABSTRACT FROM AUTHOR]

Plastic pollution has become one of the major environmental issues affecting the oceans. Millions of tonnes of plastic pollution enter the oceans every year and much of that ends up on coastlines. Microplastics and mesoplastics contamination is of particular concern, however, despite increased research, much remains unknown about their scale, distribution and impacts around the world. This study sought to determine whether a citizen science approach to coastal microplastic and mesoplastic data collection could address some of these shortcomings. We designed, developed, and tested a novel protocol that would allow volunteers to collect and record reliable data. Using the final protocol, a total of 910 samples have been collected by volunteers from 32 countries over the period of the research. This study showed that by incorporating user-centred design with established scientific methods and adapting the protocol design through user feedback, volunteers can collect data, make meaningful contributions to the gaps in scientific knowledge, benefit personally and increase their understanding of the impacts of microplastics in the environment. [ABSTRACT FROM AUTHOR]

Plastic plays an important role in agriculture, but its use has become a concerning source of pollution. While new (bio)degradable, alternative plastics are being developed and used as mulching films, their ecological impacts, in particular under field conditions, are not well understood. Furthermore, there is a notable lack of knowledge on how plastic pollution affects soil invertebrate communities. Most existing studies primarily focus on microplastics, often neglecting the impacts of mesoplastics. This study therefore compared the separate effects of two conventional (polyethylene and polypropylene) and two alternative (polyethylene containing biodegradable additives and compostable polylactic acid) mesoplastic films on plant performance (biomass, seed yield) and soil mesofaunal assemblages in a field experiment. The mesoplastics were applied at 0.1% (w/w), prior to soil being planted with Hordeum vulgare (spring barley), which was grown to maturity, for 11 weeks. Generally, there were no measurable differences between the conventional and alternative plastic treatments, however, barley exposed to mesoplastics showed reduced biomass, seed yield, and chlorophyll content, along with increased oxidative stress. Soil fauna, particularly Collembola, had lower richness and abundance when exposed to both plastic types, but assemblage structure and composition remained unchanged after 11 weeks. This study is pivotal in highlighting that both conventional and alternative plastics can similarly affect plant health and soil ecosystems. The evidence provided is essential for refining future risk assessments of agricultural plastic pollution and underscores the urgent need for more sustainable practices and materials in agriculture. [Display omitted] • Barley exposed to mesoplastics showed reduced biomass and seed yield. • Mesoplastics decreased barley chlorophyll content and increased oxidative stress. • Mesoplastics decreased soil fauna richness and abundance, especially Collembola. • Conventional and alternative plastics similarly affected plant health and soil fauna. [ABSTRACT FROM AUTHOR]

Pollution of water by plastic contaminants has received increasing attention, owing to its negative effects on ecosystems. Small plastic particles propagate in water and can travel long distances from the source of pollution. In order to research the settling motion of particles in water flow, a small-scale experiment was conducted, whereby spherical plastic particles of varying diameters were released in an open-channel flow. Three approaches were investigated to numerically simulate the motion of particles. The numerical simulation results were compared and validated with experimental data. The presented methods allow for deeper insight into particle motion in fluid flow and could be extended to a larger scale to predict the propagation of mesoplastics in natural environments. [ABSTRACT FROM AUTHOR]

This study aims to determine whether differences exist between the presence of microplastics and mesoplastics in fishes of coral reef and mangrove ecosystems, in Isla Grande, Colombian Caribbean. The collection of three species of coral reef (Centropomus undecimalis, Caranx hippos, and Lutjanus synagris) and three species of mangrove from coral reef (Centropomus undecimalis, Eugerres plumieri, and Archosargus rhomboidalis) were found to have ingested microplastics and mesoplastics, with a significantly higher in the mangrove species than in the coral reef species (1.9 vs. 1.6 items/individual). Furthermore, the average abundance and weight of microplastics and mesoplastics were significantly higher in females than in males (p < 0.05) and the abundance of microplastics and mesoplastics in the intestines was significantly higher than in the stomach (p < 0.05). PE, polyester, PVC, and PET were the most abundant polymers among common plastics found in species of the two habitats. Our findings highlight the importance of more rigorous plastic waste management strategies in areas nearby the coast and mangrove habitats. [ABSTRACT FROM AUTHOR]

• Variability in river profiles may affect the fate of plastic items in different layers in the water column. • Hard plastics were more frequently found at the river surface, while soft plastics were more frequently detected near the bottom of the river. • Estimates of plastic concentrations solely based on surface transport could result in an under- or overestimation of riverine plastic transport. • A homogeneous vertical distribution of plastics may be characterized by high-peak discharge events. Rivers act as an important transportation pathway for land-based plastic litter to the ocean. Recently, rivers have also been identified as potential sinks and reservoirs for plastics. Knowledge of plastic transport over different depth profiles in rivers remains limited. In this study, we evaluated the vertical distribution of macro- and mesoplastics, using a larvae net and a trawl net in the river Rhine and its two major branches, i.e. Waal and IJssel. Subsequently, to estimate the relationship between the surface transport of plastic items, i.e., floating items, compared to the transport in deeper layers in the water column, including suspended and bed-transported plastic, an extrapolation factor was derived per day for the middle and bottom nets divided by those found in the surface net. The observed macro- and mesoplastic OSPAR categories collected in different layers in the water column were rather consistent between different sampling techniques. Fragments of soft mesoplastic falling under the category "Plastic film plastics 0–2.5 cm (soft)" were recorded most frequently in the investigated rivers with our monitoring techniques. During larvae net monitoring, hard plastics were more frequently found at the river surface than at the middle or bottom of the river for both macroplastic and mesoplastics, while soft plastics were more frequently detected near the bottom. For larvae net monitoring, the extrapolation factor, reflecting the concentration ratio of macroplastic items transport at different depths, i.e., from the surface downwards to the middle and the bottom ranged between 0.38 to 2.2 and 0.36 to 5.7, respectively. The extrapolation factor of mesoplastic transport from the surface downwards to the middle and the bottom ranged between 0.70 to 1.84 and 0.69 to 2.57. During trawl net monitoring, the extrapolation factor, reflecting the concentration ratio, for macroplastic ranged between 0.82 and 1.30, and for mesoplastic between 0.52 and 1.40. Overall, the findings of this study show that estimates of plastic concentrations solely based on surface transport could result in an under- or overestimation of riverine plastic transport. [Display omitted] [ABSTRACT FROM AUTHOR]

• A total of 4390 meso /microplastic (MMP) particles were collected at 35 sites in 17 rivers. • The masses of all the MMP particles were directly measured by an ultramicrobalance. • The MMP mass was linearly regressed on its projected surface area on a log scale. • The mass concentrations were accurately estimated by linear regression models. • The regression models were quite reasonable for idealized geometric relationships. The quantification of the mass of meso /microplastic (MMP) particles is crucial for assessing the global inventory of ocean plastics and assessing environmental and human health risks. Herein, linear regression models between mass and projected surface area on a log scale were established by directly measuring the masses of 4390 MMP particles collected at 35 sites in 17 Japanese rivers with an ultramicrobalance. The linear regression models estimated mass concentrations more accurately than any previous method based on geometric volume assuming several three-dimensional shapes. Additionally, linear regression models were quite reasonable for determining the geometric relationships of idealized cuboid particles. The slope of the linear regression models was dependent on the three-dimensional shapes of the particles, and their intercept was determined according to their third dimension. Moreover, the third dimension led to uncertainty in the mass estimation of particles; thus, the accuracies of the previous methods were relatively poor. Nevertheless, two limitations for mass measurement by linear regression models were identified, which determined the size range of the MMP particles on the projected surface area (ranging from 10−4 mm2 to 102 mm2) that is applicable for mass estimation of the particles collected from riverine and marine environments. Our results could be used to accurately estimate the mass concentrations in aquatic environments and provide insights into the geometric relationships between the mass and size of MMP particles. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • First lichen passive biomonitoring of plastic pollution in remote areas. • 253 microplastics trapped by 90 lichen samples in natural, protected, urban areas. • Increasing (double) accumulation of MPs from the natural site to the urban site. • First mesoplastics found on lichens from airborne pollution. • Shortest fibers at the natural site, longer fibers at the urban site. Currently, natural and urban ecosystems are affected by different types of atmospheric deposition, which can compromise the balance of the environment. Plastic pollution represents one of the major threats for biota, including lichens. Epiphytic lichens have value as bioindicators of environmental pollution, climate change, and anthropic impacts. In this study, we aim to investigate the lichen bioaccumulation of airborne microplastics along an anthropogenic pollution gradient. We sampled lichens from the Genera Cladonia and Xanthoria to highlight the effectiveness of lichens as tools for passive biomonitoring of microplastics. We chose three sites, a "natural site" in Altipiani di Arcinazzo, a "protected site" in Castelporziano Presidential estate and an "urban site" in the centre of Rome. Overall, we sampled 90 lichens, observed for external plastic entrapment, melt in oxygen peroxide and analysed for plastic entrapment. To validate the method, we calculated recovery rates of microplastics in lichen. Particularly, 253 MPs particles were detected across the 90 lichen samples: 97 % were fibers, and 3 % were fragments. A gradient in the number of microplastic fibers across the sites emerged, with increasing accumulation of microplastics from the natural site (n = 58) to the urban site (n = 116), with a direct relationship between the length and abundance of airborne microplastic fibers. Moreover, we detected the first evidences of airborne mesoplastics entrapped by lichens. On average, the natural site experienced the shortest fibre length and the centre of Rome the longest. No differences in microplastics accumulation emerged from the two genera. Our results indicated that lichens can effectively be used for passive biomonitoring of microplastic deposition. In this scenario, the role of lichens in entrapping microplastics and protecting pristine areas must be investigated. Furthermore, considering the impact that airborne microplastics can have on human health and the effectiveness of lichens as airborne microplastic bioindicators, their use is encouraged. [ABSTRACT FROM AUTHOR]

Plastics, particularly mesoplastics, dominate beach debris and act as carriers of hazardous chemicals, either initially present in plastics or absorbed from the surrounding environment. In this study, mesoplastics were collected from five beaches in the southern region of Spain to investigate their potential impact on marine life. In vitro assays employing fish liver cells (PLHC-1) were conducted to evaluate the toxicity of methanolic extracts derived from intact mesoplastics and after simulated photodegradation. LC-MS analysis of the methanolic extracts revealed the presence of organophosphate esters, phthalates, and phthalate alternatives. The extracts from photodegraded plastics generally showed higher cytotoxicity, ability to generate reactive oxygen species (ROS), and genotoxicity (micronuclei formation) than those from intact mesoplastics. All the extracts induced EROD activity in PLHC-1 cells, indicating the presence of significant amounts of CYP1A inducers in beach mesoplastics. Thus, mesoplastics contain chemicals able to induce cytotoxicity and genotoxicity in PLHC-1 cells, and further photodegradation of mesoplastics facilitates the release of additional chemicals, increasing the overall toxicity. This work also highlights the usefulness of cell-based assays to better define the risks of plastic pollution. [Display omitted] • Plastic extracts triggered toxic effects in fish liver PLHC-1 cells. • Increased toxicity detected after photodegradation of beach mesoplastics. • Organophosphate esters and phthalates detected in beach plastics. • Weak correlation observed between plastic additives analyzed and toxicity. [ABSTRACT FROM AUTHOR]

Meso- and microplastics (MMPs) have attracted attention as globally dispersed environmental pollutants. However, little is known about the transfers of MMPs between aquatic and terrestrial systems. A large watershed-estuarine area of Bohai Sea was used as a case study, and soils and sediments were sampled adjacent to each other at a wide range of sites. MMPs were detected in all sediments (6.7–320 MMPs/kg) and soils (40–980 MMPs/kg), with the average abundance in soils double that in sediments on a dry mass basis. MMPs < 1 mm were most abundant and the dominant shape was film in both sediments and soils. Over twenty polymer types were detected and their compositions in sediments and soils were different. MMP abundance in sediments was lower in the upper catchment than the lower catchment, while the abundance of soil MMPs was the opposite. Despite the proximity of the sampling locations, no clear relationship was identified between the soil and sediment MMPs, suggesting low transfer between the two compartments and high heterogeneity of the sources. The missing associations between aquatic and terrestrial MMPs should be systematically examined in future studies, which is crucial for understanding the environmental fate and impacts of MMPs. [Display omitted] • Relationships between aquatic and terrestrial meso-microplastics (MMPs) are studied. • Average abundance of MMPs in soils doubles that in sediments on a dry mass basis. • Film MMPs <1 mm are the most abundant in both sediments and soils. • Sediment and soil MMPs show different distribution, polymer types, and colors. • No association is found between adjacent sediment and soil MMPs. [ABSTRACT FROM AUTHOR]

Meso- and microplastics (MMPs) have attracted attention as globally dispersed environmental pollutants. However, little is known about the transfers of MMPs between aquatic and terrestrial systems. A large watershed-estuarine area of Bohai Sea was used as a case study, and soils and sediments were sampled adjacent to each other at a wide range of sites. MMPs were detected in all sediments (6.7–320 MMPs/kg) and soils (40–980 MMPs/kg), with the average abundance in soils double that in sediments on a dry mass basis. MMPs < 1 mm were most abundant and the dominant shape was film in both sediments and soils. Over twenty polymer types were detected and their compositions in sediments and soils were different. MMP abundance in sediments was lower in the upper catchment than the lower catchment, while the abundance of soil MMPs was the opposite. Despite the proximity of the sampling locations, no clear relationship was identified between the soil and sediment MMPs, suggesting low transfer between the two compartments and high heterogeneity of the sources. The missing associations between aquatic and terrestrial MMPs should be systematically examined in future studies, which is crucial for understanding the environmental fate and impacts of MMPs. [Display omitted] • Relationships between aquatic and terrestrial meso-microplastics (MMPs) are studied. • Average abundance of MMPs in soils doubles that in sediments on a dry mass basis. • Film MMPs <1 mm are the most abundant in both sediments and soils. • Sediment and soil MMPs show different distribution, polymer types, and colors. • No association is found between adjacent sediment and soil MMPs. [ABSTRACT FROM AUTHOR]

Much of the plastic waste entering the sea is thought to be transported from land by rivers, yet little is known about the distances over which rivers transport plastic. To address this knowledge gap, we collected surface water samples from the Orange-Vaal River at the end of the wet and dry seasons. The Vaal River drains South Africa's main urban-industrial centre, whereas the upper Orange River is sparsely populated. Below their confluence, the river flows through increasingly arid regions with very low human populations before entering the Atlantic Ocean. We collected bulk water samples from 33 bridges to test for microplastic and microfibre (0.025–1 mm) pollution and conducted observations for macrodebris (>50 mm). Where possible, we sampled for plastic fragments (>1 mm) using a neuston net. Microfibres and microplastics were found at every site (1.7 ± 5.1 L−1, >99% fibres) and accounted for 99% of the number of items recorded. Microfibres and microplastics were particularly abundant in the lower reaches during the period of low flow prior to the wet season flush. Macrodebris and larger microplastics were orders of magnitude less abundant (observations: 0.0002 ± 0.0007 items·m−2; neuston net: 0.34 ± 0.93 items·m−2). However, at sites where larger items were found, they comprised most of the mass of plastic. Larger plastics were found mostly at sites in the upper reaches of the Vaal River. Our results suggest that, while the Orange-Vaal River system may be a source of microfibres to the Atlantic Ocean, larger plastic items typically only travel short distances. The Orange-Vaal River system therefore does not appear to be a major source of plastics into the Atlantic Ocean, at least under regular flow conditions. Unlabelled Image • Microfibres found at all sites and in 90% of replicates • Macroplastics and larger microplastics retained close to point sources • Mostly microfibres found at the Orange River mouth • Estimated annual export of 1.7 (1.1–3.1) t of microfibres to the Atlantic Ocean [ABSTRACT FROM AUTHOR]

Plastic pollution is a global problem with great local and regional variability. Plastic litter reaches beaches directly and indirectly through different pathways, due to both terrestrial and marine pressures. In this study, we assess and characterize meso and microplastic pollution on four Uruguayan oceanic beaches along a gradient of tourist use within a complex regional coastal marine system. In Punta del Diablo we found a total mean density of 106 items m−2 of different debris (pellets, fragments, and foams) with different polymeric compositions, and diverse persistent bioaccumulative and toxic chemicals (PAHs, PCBs, OCs, heavy metals). However, the trend of plastic debris densities along this gradient was not what was expected. Fabeiro , one of the sites furthest from the urban center, had the highest total mean density of plastics (292 items m−2) suggesting that marine influences (winds, currents, and beach orientation) have a preponderant role in the distribution of micro and mesoplastics. Meanwhile, the density in the urban site (Pueblo) was highest during summer (March, 201 items m−2), 200 times higher than the density observed in winter (July, 1 item m−2). Although this difference could be associated to the peak season (southern summer), the analysis of types of plastics (171 pellets m−2 vs. 8 cigarette butts m−2) suggested a predominance of marine inputs. Seasonal changes in the configuration of the beaches due to natural geomorphological dynamics imply alternating states (Source or Sink of debris) that also affect the final density of plastics in the system. The relative importance of both sources is highly variable throughout the year and understanding them may directly improve beach management and stranded coastal plastic litter cleaning. Unlabelled Image • Trend of plastic debris densities along the use gradient were not as expected. • Marine coastal currents are particularly important in the distribution of MPs. • Beach alternate states (Source/Sink) affect the balance of plastics in the beach system. • Could coastal dynamics be a key element for ecosystem-based adaptation (EbA) strategies for stranded plastic litter? [ABSTRACT FROM AUTHOR]

Small plastic debris is one of the most significant emerging pollutants, due to their extreme durability and synthetic nature, possessing a tremendous threat to the aquatic environment. In the present study, sediments of river Ganga at a lower stretch were analyzed for distribution of meso and microplastics at seven different locations viz. Buxar, Patna, Bhagalpur, Nabadwip, Barrackpore, Godakhali and Fraserganj. All the sediments were found to contain mesoplastics (>5 mm) and microplastics (<5 mm) particles with varying degree of the mass fraction (11.48 to 63.79 ng/g sediments), numerical abundance (99.27–409.86 items/kg) and morphotypes. Analysis of the mesoplastics with FT-IR revealed polyethylene terepthalate (39%) as the major contributing plastic debris in the sediments followed by polyethylene (30%). Statistical analysis revealed a strong correlation between microplastics abundance and the pollution traits, BOD and available phosphate, of water and sediment, respectively. This study exhibits the spatial distribution of meso and microplastics in the highly populated locations along the river Ganga emphasizing the attention to be given to this emerging pollutant in the inland river system underlining their role as a transporter of plastic fragments finally to the ocean. Unlabelled Image • Meso and microplastics distribution in Ganga River sediments was estimated. • Polyethylene terephthalate and polyethylene were found to be dominant plastic debris. • Film and fiber plastic debris were dominant types in the sediments of Ganga River. • A strong correlation exists between microplastics abundance and pollution traits. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) and mesoplastics are able to sorb harmful substances and often contain additives, e.g., endocrine disrupting chemicals (EDCs), that can cause adverse effects to organisms. The present study aims to determine EDC concentrations and their endocrine activities in leachates of field-collected marine MPs and mesoplastics under stress conditions that are known to occur during the plastic life cycle. Estrogens were the dominant EDCs on plastic particles and were either concentrated from the surrounding water or originated from plastic manufacturing. Bisphenol A had the highest detection frequency (75%) with an average concentration of 475 ± 882 μg/kg, followed by bisphenol S, octylphenol and nonylphenol. Moreover, smaller marine MPs leached greater quantities of EDCs because the sorption from surrounding seawater is more efficient for smaller particles. It was found that normal life stresses such as microwaving (MW) and autoclaving (AC) can decrease EDC concentrations, but solar irradiation (solar) can increase EDC concentrations in leachates. Even though organisms with higher metabolic ability exhibited greater estrogenic effects, the comprehensive toxicity of plastic leachates after common life treatments was still limited (below the EC 10 value) if 0.1% is taken as the EDC uptake from plastic. In future studies, the accurate contribution of plastic bound EDCs needs to be further explored, and the monitoring of MPs and mesoplastics in the human diet remains important because the concentrations of these plastics may change in the future. Unlabelled Image • Estrogens are dominant EDCs on marine micro- and mesoplastics. • Smaller microplastics released more EDCs and had higher detection frequencies. • Microwaving and autoclaving decreased but solar irradiation increased EDCs. • Micro-/mesoplastic-containing seafood cooking led to negligible estrogenic effects. [ABSTRACT FROM AUTHOR]