The incidence of plastic ingestion by fishes: from the prey's perspective

Ecological risk assessment of microplastics and mesoplastics in six common fishes from the Bay of Bengal Coast

Plastic particles have emerged as a growing threat to both ecosystems and human well-being, as they are being ingested and accumulate at different trophic levels. However, microplastic and mesoplastic contamination and its risk to coastal and marine water fish have not been well studied, particularly in the northern Bay of Bengal. In this study, the presence of small-scale plastic particles (micro- and meso-sized) in the gastrointestinal tract (GIT) and muscles of six edible fish species from the northern Bay of Bengal Coast were identified and analyzed. The overall range of microplastics was 1.74 ± 0.23-3.79 ± 2.03items/g in muscle and 0.54 ± 0.22-5.96 ± 3.16 items/g in the GIT, with 16.38 ± 8.08-31.88 ± 12.09 items/individual. No mesoplastics were found in muscle tissue, but they were present in the GIT at concentrations ranging from 0.33 ± 0.27 to 0.03 ± 0.02 items/g and from 0.51 ± 0.05to 1.38 ± 1.01 items/individual. Lepturacanthus savala accumulated the most microplastics in muscle, and Harpadon nehereus had the least. In addition, the highest levels of mesoplastics were detected in the GIT of Polynemus paradiseus and the lowest was detected in the GIT of Lutjenus sanguineus. Omnivorous fish showed higher plastic concentrations than carnivorous fish, which was linked to dietary habits, feeding strategies and digestive processes. Plastic material predominantly accumulated in the GIT rather than in the muscle. The majority of ingested plastic particles were fibres (95.18 %), were violet in color (34 %), and were < 0.5 mm in size (87 %). The dominant microplastic polymers included 38 % PE, 15 % PP, 33 % PU, and 14 % CES. In contrast, the prevalent mesoplastic polymers comprised 45 % PE, 19 % PP, 13 % PS, 16 % PA, and 7 % PET. Subsequently, a hazard analysis using the polymer hazard index (PHI) revealed that plastic contamination was of distinct hazard categories for different polymer types, ranging from grade I (<1) to grade IV (100-1000). The assessment of the contamination factor (1 < CF < 3) and pollution load index (PLI > 1) indicated moderate contamination of fish by the ingestion of plastic debris. This study provides the foremost evidence for the presence of mesoplastics and microplastics in coastal and marine fish in the study region, paving the way for future investigations and policy implementation.

Effect of micro-plastic particles on coral reef foraminifera

Foraminifera are single-celled protists which are important mediators of the marine carbon cycle. In our study, we explored the potential impact of polystyrene (PS) microplastic particles on two symbiont-bearing large benthic foraminifera species-Heterostegina depressa and Amphistegina lobifera-over a period of three weeks, employing three different approaches: investigating (1) stable isotope (SI) incorporation-via 13C- and 15N-labelled substrates-of the foraminifera to assess their metabolic activity, (2) photosynthetic efficiency of the symbiotic diatoms using imaging PAM fluorometry, and (3) microscopic enumeration of accumulation of PS microplastic particles inside the foraminiferal test. The active feeder A. lobifera incorporated significantly more PS particles inside the cytoplasm than the non-feeding H. depressa, the latter accumulating the beads on the test surface. Photosynthetic area of the symbionts tended to decrease in the presence of microplastic particles in both species, suggesting that the foraminiferal host cells started to digest their diatom symbionts. Compared to the control, the presence of microplastic particles lead to reduced SI uptake in A. lobifera, which indicates inhibition of inorganic carbon and nitrogen assimilation. Competition for particulate food uptake was demonstrated between algae and microplastic particles of similar size. Based on our results, both species seem to be sensitive to microplastic pollution, with non-feeding H. depressa being more strongly affected.

Monitoring plastic pellet pollution in coastal environments through handheld Raman spectroscopy: Data from the Mediterranean coasts (Southern Italy)

This paper examines the distribution and chemical properties of beached plastic pellets along the Ionian and Tyrrhenian coasts of Southern Italy. Three locations have been sampled: Agnone Bagni (SR) and Paradiso (ME) on the Ionian coast of Sicily, Baia del Tono in Milazzo (ME) on the Sicilian Tyrrhenian coast, and Pizzo Calabro (VV) in Calabria on the Tyrrhenian coast. Variations in shape, size, compactness, color, and other physical features, correlated with residence times and transport, has been highlighted. Raman spectroscopy, used in a portable configuration, enabled rapid identification of polymer types, demonstrating its utility for on-site plastic pollutant monitoring. Polyethylene and polypropylene were the predominant polymers. Principal component analysis of the spectra determined the optimal chemometric classification of pellets by composition, avoiding interference or distortion. In conclusion, the study provided preliminary insights into pellet abundance, composition, weathering extent, and distribution across these shorelines, underscoring the importance of regular beach monitoring.

Tracing beach litter sources: Drink lids tell a different story from their bottles

Water and soft drink bottles made from polyethylene terephthalate (PET) sink at sea unless they contain trapped air, whereas their lids are made from polymers that float and can drift long distances. We sampled loose lids and bottles at 21 South African beaches to compare their origins. The proportions of foreign-made bottles and lids were correlated, and increased away from urban centres, indicating that much land-based litter strands close to source areas. Over 80 % of foreign-made drink bottles and 90 % of lids came from Asia, but most bottles were manufactured in China, Malaysia-Singapore and the UAE, and were dumped from ships. By comparison, most loose lids were in poor condition after being carried across the Indian Ocean from Indonesia by the South Equatorial Current. Reducing PET drink bottles at sea requires enforcement of regulations banning dumping at sea, whereas reducing their lids requires better control of littering in source countries.

Illegal dumping from ships is responsible for most drink bottle litter even far from shipping lanes

Recent studies using bottles as tracers have shown that illegal dumping from ships is responsible for the rapid increase in drink bottles washing up on oceanic islands and at remote continental beaches away from local litter inputs. However, these studies have been in areas with moderate to high levels of shipping activity. I examined bottles stranded on the Pitcairn Islands in the central South Pacific, which are far from major shipping routes. Drink bottles from Asia dominated, with most coming from China. The top four brands (three Chinese and one multinational) were the same as at Tristan da Cunha in the central South Atlantic Ocean, which lies on the shipping route between South America and Asia. Bottle ages also were similar at Pitcairn and Tristan, indicating that vessels are the main source of bottles at both islands. Stricter controls are needed to reduce illegal dumping of plastics at sea.

A critical review on the evaluation of toxicity and ecological risk assessment of plastics in the marine environment

The increasing production of plastics together with the insufficient waste management has led to massive pollution by plastic debris in the marine environment. Contrary to other known pollutants, plastic has the potential to induce three types of toxic effects: physical (e.g intestinal injuries), chemical (e.g leaching of toxic additives) and biological (e.g transfer of pathogenic microorganisms). This critical review questions our capability to give an effective ecological risk assessment, based on an ever-growing number of scientific articles in the last two decades acknowledging toxic effects at all levels of biological integration, from the molecular to the population level. Numerous biases in terms of concentration, size, shape, composition and microbial colonization revealed how toxicity and ecotoxicity tests are still not adapted to this peculiar pollutant. Suggestions to improve the relevance of plastic toxicity studies and standards are disclosed with a view to support future appropriate legislation.

The role of microbe-microplastic associations in marine Nematode feeding behaviors

Fauna across many taxa and trophic levels have been shown to consume microplastics (MPs) in experiments, providing evidence that supports field-based gut content assessments. Multiple explanations exist regarding why fauna consume MPs, one of which posits that microbial growth on MPs may facilitate faunal ingestion. However, laboratory assessments on the reasons why MPs are consumed remain limited. Here, we assessed if the presence of microbes on MPs altered marine nematode feeding behaviors across current and potential future concentrations of MPs in a local system. We used a microcosm experiment in which field-collected sediment was spiked with bacterially treated or untreated fluorescent plastic microbeads (1.0-5.0 μm) in concentrations of 102, 104, and 106 per microcosm, representing local and potential future concentrations of MPs. Ingestion by the dominant interstitial fauna was investigated after 0, 3, and 7 days using bright field microscopy. Nematodes were the only fauna across microcosms that consumed MPs, but this consumption was variable and there were no apparent trends across exposure time, bacterial treatment, or MP concentration. There were also no genera- or feeding-type-specific trends in the number of MPs consumed, though four of the top five nematode genera that consumed MPs were pollution-tolerant genera. Our study demonstrates that microbe-MP associations do not drive marine nematodes to eat MPs, especially at local field concentrations. While there were no trends across any of the nematode genera in our study, we recognize that unrealistic MP concentrations in other studies may provide alternative explanations for nematode consumption of MPs.

The bioaccessibility of adsorped heavy metals on biofilm-coated microplastics and their implication for the progression of neurodegenerative diseases

Microplastic (MP) tiny fragments (< 5 mm) of conventional and specialized industrial polymers are persistent and ubiquitous in both aquatic and terrestrial ecosystem. Breathing, ingestion, consumption of food stuffs, potable water, and skin are possible routes of MP exposure that pose potential human health risk. Various microorganisms including bacteria, cyanobacteria, and microalgae rapidly colonized on MP surfaces which initiate biofilm formation. It gradually changed the MP surface chemistry and polymer properties that attract environmental metals. Physicochemical and environmental parameters like polymer type, dissolved organic matter (DOM), pH, salinity, ion concentrations, and microbial community compositions regulate metal adsorption on MP biofilm surface. A set of highly conserved proteins tightly regulates metal uptake, subcellular distribution, storage, and transport to maintain cellular homeostasis. Exposure of metal-MP biofilm can disrupt that cellular homeostasis to induce toxicities. Imbalances in metal concentrations therefore led to neuronal network dysfunction, ROS, mitochondrial damage in diseases like Alzheimer's disease (AD), Parkinson's disease (PD), and Prion disorder. This review focuses on the biofilm development on MP surfaces, factors controlling the growth of MP biofilm which triggered metal accumulation to induce neurotoxicological consequences in human body and stategies to reestablish the homeostasis. Thus, the present study gives a new approach on the health risks of heavy metals associated with MP biofilm in which biofilms trigger metal accumulation and MPs serve as a vector for those accumulated metals causing metal dysbiosis in human body.

Microplastics pollution in freshwater fishes in the South of Italy: Characterization, distribution, and correlation with environmental pollutants

In this study, we investigated the presence, abundance, and chemical nature of microplastics (MPs) in the freshwater fish gastrointestinal tract in the South of Italy, and evaluated the possible correlation between MPs and environmental pollutants. Fifty specimens belonging to five species (Scardinius erythrophthalmus, Barbus barbus, Rutilus rubilio, Leuciscus cephalus, Salmo trutta), from twenty sites were collected. MPs chemical feature was identified by means of Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) and Raman microscopy. MPs were represented by 34.86 % fragments, film, and foam (all together MPs) and 65.14 % by fibers (MFs). The mean number of MPs/MFs per fish ranged from 6.25 ± 4.35 in R. rubilio and 2.26 ± 1.94 in B. barbus. The highest number of MPs/MFs per g of GIT was found in R. rubilio (9.07 ± 9.66), and the lowest in S. erythrophthalmus (0.75 ± 0.53). The highest number of MPs/MFs per fish species was found in L. cephalus (16), and the lowest in S. erythrophthalmus (4). Black predominated in every type of plastic debris identified, followed by blue and white, respectively for MFs and MPs. Polyethylene (PE), polyethylene terephthalate (PET), polystyrene (PS), and polypropylene (PP), were the main plastic polymers found. At fish sampling sites, comparing concentrations in soils of potentially toxic elements and persistent organic pollutants with the number of MPs/MFs in fish, a significant correlation was noted with polychlorinated biphenyls (PCBs) and, in particular, with PCB 105, PCB 118, PCB 156, PCB 157, and PCB 167. A strong correlation was also observed with all types of polycyclic aromatic hydrocarbon (PAHs) particularly with benzo(ghi)perylene, dibenz(a,h)anthracene, benzo(b)fluoranthene, benz(a)anthracene, benzo(a)pyrene, and pyrene. The results of this study would be useful to draft management and action plans, promote intervention plans aiming at removing threats to species and habitats, and address ways of renaturalization.

Diet and Plastic Ingestion in the Blackmouth Catshark Galeus melastomus, Rafinesque 1810, in Italian Waters

Galeus melastomus is the most common Pentanchidae in the Mediterranean Sea. A scavenger and opportunistic feeder, and despite the wide distribution, little is known about its feeding habits in Italian waters. The main purpose of this study was to investigate the diet of the blackmouth catshark by analysing the stomach contents. The specimens analysed were obtained from five populations of the Tyrrhenian and of the Ionian Seas, collected from a depth between 40 and 700 m. A total of 259 stomachs were analysed. The stomach contents were grouped into macro-categories and identified to the lowest taxonomic level possible. Crustaceans such as Parapenaeus longirostris, the Cephalopods Heteroteuthis dispar and Onychoteuthis banksii, and Osteichthyes, mostly Myctophidae, were identified. Plastic debris was also found among the stomach contents and classified according to its colour and shape. Osteichthyes represent the most abundant item (44%), above all the Myctophidae family, except for the catshark population from Tuscany, in which the most frequent species were Cephalopods, such as Abralia veranyi and Heteroteuthis dispar. Differences in the plastic debris contents were also observed between the Tuscany population and other populations. These could be explained as a probable consequence of the different depths at which the blackmouth catshark populations were sampled.

Global occurrence, drivers, and environmental risks of microplastics in marine environments

With an increasing quantity of plastic waste being discharged into the oceans, marine microplastic (MP) pollution has received widespread attention. However, the global occurrence characteristics, environmental risks, driving factors, and source-sink relationships remain unclear. In this study, we conducted a meta-analysis based on 165 articles about marine MP pollution. It was found that the global marine MP abundance displayed a significant spatial heterogeneity, and the distribution pattern was influenced by offshore distance, population density, and economic development. The morphological characteristics of MPs showed a significant difference between seawater and marine sediment, and small-size MPs (<1 mm) accounted for the majority of all MPs in the marine environment. The environmental risk assessment revealed that most of the marine MP pollution still remains at low concentrations in the global context, with the Polyurethane (PU), Polyacrylonitrile (PAN), and Polyvinyl chloride (PVC) types of MPs showing high environmental-risk contributions. In addition, land-based waste and marine operations, which were considered to be the dominant sources of marine MPs, primarily aggregated at nearshore submarine areas, in the water column, and in the deep-sea bottom environment. This study suggested that the combination of a meta-analysis and Monte Carlo simulation can provide much valuable information regarding the global occurrence characteristics and environmental risks of marine MPs.

Biofilm formation strongly influences the vector transport of triclosan-loaded polyethylene microplastics

This study aimed at evaluating the influence of biofilm in the role of microplastics (MPs) as vectors of pollutants and their impact on Daphnia magna. To do this, virgin polyethylene MPs, (PE-MPs, 40-48 μm) were exposed for four weeks to wastewater (WW) from influent and effluent to promote biofouling. Then, the exposed PE-MPs were put in contact with triclosan. Finally, the toxicity of TCS-loaded and non-TCS loaded PE-MPs were tested on the survival of D. magna adults for 21 days. Results from metabarcoding analyses indicated that exposure to TCS induced shifts in the bacterial community, selecting potential TCS-degrading bacteria. Results also showed that PE-MPs were ingested by daphnids. The most toxic virgin PE-MPs were those biofouled in the WW effluent. The toxicity of TCS-loaded PE-MPs biofouled in the WW effluent was even higher, reporting mortality in all tested concentrations. These results indicate that biofouling of MPs may modulate the adsorption and subsequent desorption of co-occurring pollutants, hence affecting their potential toxicity towards aquatic organisms. Future studies on realistic environmental plastic impact should include the characterization of biofilms growing on plastic. Since inevitably plastic biofouling occurs over time in nature, it should be taken into account as it may modulate the sorption of co-occurring pollutants.

Laboratory simulated aging methods, mechanisms and characteristic changes of microplastics: A review

Microplastics (MPs) aging occurs in all environmental medias and affects the environmental behaviour and toxicity of MPs. Due to the extremely slow process of aging, laboratory simulated aging methods have had to be used to research the properties, behaviour, toxicity and effects of aged MPs. However, multiple laboratory aging methods with different mechanisms have led to divergent viewpoints on the characteristics, behavior and toxicity of aged MPs. Therefore, this paper reviewed the main laboratory MPs aging methods and mechanism, including those that involve UV, advanced oxidation processes (AOPs), sunlight or simulated sunlight, chemical treatment, heat, plasma radiation, etc. As a technology with a low time cost, AOPs have potential and are recommended. Physical, chemical, and coupled aging significantly alter MPs surface topography and functional groups, which affect MPs adsorption, migration and toxicity. However, the effects of aging on environmental behaviour and toxicity are highly uncertain. The carbonyl index (CI) and O/C ratio are generally applied to evaluate the MPs aging degree. This review highlights the need to provide adequate information on coupled simulated aging methods to allow better elucidation of the underlying mechanisms of aging and its effect on MPs environmental behaviour and toxicity.

Far from urban areas: plastic uptake in fish populations of subtropical headwater streams

This study investigated the occurrence of plastic particles in the digestive tracts of fish from headwater streams in a human-thinly populated region of the subtropical Sinos River basin in southern Brazil. In total, 258 individuals from 17 species were collected using electric fishing. Thirty-eight percent (38%) of the specimens contained plastic particles. All of them were fibers, with a maximum count of 43 per individual. Plastic fibers were the fourth most abundant food category. Results showed that the uptake of these plastic particles was proportional to the number of ingested food items. Fiber counts in the guts correlated with the uptake of Trichoptera, which are invertebrates using plastic particles to construct their protective cases. No significant difference in plastic uptake was detected between benthic and water column fish. No evidence of bioaccumulation of plastic particles was found in the intestines. The distance from urban areas was not related to the number of ingested plastic particles, concluding that plastics are ubiquitous and available to biota, even in remote locations. The most probable source of these particles is residences close to the streams which discharge the sewage of washing machines without any treatment.

Sources, sinks and transformations of plastics in our oceans: Review, management strategies and modelling

Currently, 60-80 % of litter is plastic, and almost 10 % ends up in the ocean directly or indirectly. Plastics often suffer from photooxidation producing microplastics and these microplastics derived from the breakdown of larger plastics are called secondary microplastics. These compounds simply cannot be extracted from the oceans, and once mixed, they enter the food chain and may have toxic effects. This work reviews the current existing information on the topic in the scientific literature. Then, the current plastic management strategies in the marine environment are analysed, with the objective of identifying possible needs and improvements from a sustainable point of view, and to define new approaches. Simultaneously, a material flows analysis in different media of the marine environment is carried out using system dynamics. A preliminary model of plastics mobilization into the ocean to other media of the marine environment (like sediments and biota) is developed and validated with the existing data from the previous steps of the work. This work expands the current knowledge on the plastics management, their transformations and accumulation in the marine environment and the harmful effects on it. Likewise, preliminary dynamic model of mobilization of plastics in the ocean is implemented, run, and validated. The developed model can be used to predict trends in the distribution of the plastics in the ocean with time. In addition, the most important reservoirs of plastics in the ocean can be observed. Although plastics undergo transformations in the marine environment, it is not a means of disposal since most of them are non-biodegradable. Most plastics accumulate on the seabed. The proportion of microplastics found in sediments is higher than that of macroplastics.

Microplastic pollution in the surface waters of Vava'u, Tonga

Marine plastic pollution, particularly microplastics, has been recognised as a global issue in the recent years, but research efforts in the Pacific are lagging. We carried out research on microplastics contamination of surface waters of the Vava'u archipelago, Tonga. Since microplastics smaller than the standard mesh size (333-335 μm) are readily reported in the literature on microplastics, we used a finer plankton net (100 μm) to determine the proportion of captured microplastics smaller than 300 μm. Isolated microplastics were counted and measured using stereomicroscope with polymer identification performed by FTIR spectroscopy. The analysis revealed high microplastics concentrations (329,299.7 ± 40,994.2 pcs km^-2 or 1.05 ± 0.13 pcs m^-3). The proportion of particles smaller than 300 μm was 40 %. The predominant type of microplastics in surface waters were small bits of white film, which we associated with cement-filled white bags used to construct docks throughout Vava'u, often heavily eroded.

Caddisfly Larvae are a Driver of Plastic Litter Breakdown and Microplastic Formation in Freshwater Environments

Plastic litter is now pervasive in the aquatic environment. Several marine and terrestrial organisms can fragment plastic with their feeding appendages, facilitating its breakdown and generating microplastics. However, similar studies with freshwater organisms are extremely limited. We explored the interactions between the caddisfly larvae Agrypnia sp. and polylactic acid (PLA) film. The use of plastic by larvae to build their protective cases was investigated, along with their ability to fragment the plastic film as they do with leaf litter. Caddisfly consistently incorporated PLA into their cases alongside leaf material. They also used their feeding appendages to rapidly fragment PLA-forming hundreds of submillimeter-sized microplastics. Although larvae showed a preference for leaf material when constructing cases, plastic use and fragmentation still occurred when leaf material was replete, indicating that this behavior is likely to occur in natural environments that are polluted with plastics. This is thought to be the first documented evidence of active plastic modification by a freshwater invertebrate and therefore reveals a previously unidentified mechanism of plastic fragmentation and microplastic formation in freshwater. Further work is now needed to determine the extent of this behavior across freshwater taxa and the potential implications for the wider ecosystem. Environ Toxicol Chem 2022;41:3058-3069. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Quantifying the risk of plastic ingestion by ichthyofauna in the Balearic Islands (western Mediterranean Sea)

This study investigates the risk plastic debris ingestion poses to coastal marine taxa in the Balearic Islands in the western Mediterranean Sea. Here, we use species observations and environmental data to model habitat maps for 42 species of fish. For each species, we then match estimates of habitat suitability against the spatial distribution of plastic debris to quantify plastic exposure, which we further combine with species-wise ingestion rates to map the risk of plastic ingestion. The results indicate that the risk of plastic ingestion is particularly high in the north-west and south-east regions and the risks varied strongly between species, with those at higher trophic levels being the most vulnerable overall. Extending this work to other coastal regions within the Mediterranean Sea and beyond will allow managers and policymakers to target the most appropriate areas and types of interventions for mitigating plastic pollution on coastal diversity in the marine environment.

Bottled & canned - Anthropogenic debris as an understudied ecological trap for small animals

Nowadays, littering is one of the biggest challenges that environmental conservation is facing. Although beverage containers, such as bottles and cans, belong to the most common threats in this context, their effect on animals has been poorly studied. The aim of this study was to assess the diversity and mortality level of the animal taxa entering discarded containers and to investigate which container features influence the number and functional composition of the trapped animals. The study was conducted in 10 urban woodlands in the city of Wrocław, Poland. In total, 939 open containers were collected. In 56% of them, a total number of 10,162 dead individuals (10,139 invertebrates and 23 vertebrates) was found. The most common amongst them were insects (orders: Coleoptera, Diptera, Hymenoptera), malacostracans (Isopoda), arachnids (Opiliones, Sarcoptiformes) and gastropods (Stylommatophora). The number of dead animals was affected positively by the container capacity and was significantly higher in glass and plastic bottles when compared to aluminium cans. At the same time, the presence of a neck negatively affected the number of dead animals. Container capacity was also positively correlated with the abundance of the most common functional groups: predators, phytophages and saprophages. Moreover, colourless and green, but not brown, containers were a significant predictor for the abundance of the latter two groups. Our study revealed that discarded containers constitute an ecological trap for many groups of animals. There is an urgent need to reduce the amount of rubbish in the environment by, for example, the implementation of regional and international regulations addressing the problem of littering, or organising repeated clean-up and educational activities.

Distribution characteristics of microplastics in the soil of mangrove restoration wetland and the effects of microplastics on soil characteristics

The dense vegetation in the wetland could effectively retain microplastic particles, and the distribution of microplastics varied significantly under different planting densities. In addition, microplastics in the soil environment can affect soil properties to a certain extent, which in turn can affect soil functions and biodiversity. In this study, we investigated the distribution of soil microplastics in a mangrove restoration wetland under different planting densities and their effects on wetland soil properties. The results indicated that the average abundance of soil microplastics was 2177.5 n/500 g, of which 70.9% exhibited a diameter ranging from 0.038-0.05 mm, while the remaining soil microplastics accounted for less than 20% of all microplastics, indicating that smaller-diameter microplastics were more likely to accumulate in wetland soil. The microplastic abundance could be ranked based on the planting density as follows: 0.5 × 0.5 m > 1.0 × 0.5 m > 1.0 × 1.0 m > control area. Raman spectroscopy revealed that the predominant microplastic categories in this region included polyethylene terephthalate (PET, 52%), polyethylene (PE, 24%) and polypropylene (PP, 15%). Scanning electron microscopy (SEM) images revealed fractures and tears on the surface of microplastics. EDS energy spectra indicated a large amount of metal elements on the surface of microplastics. Due to the adsorptive features of PET, this substance could influence the soil particle size distribution and thus the soil structure. All physicochemical factors, except for the soil pH, were significantly affected by PET. In addition, the CV analysis results indicated that soils in vegetated areas are more susceptible to PET than are soils in bare ground areas, leading to greater variation in their properties.

Characterization of foamed plastic litter on Danish reference beaches - Pollution assessment and multivariate exploratory analysis

Foamed litter comprise a significant amount of the pollution at beaches globally. This group represents a variety of foamed items and fragments originating from different applications and sources. Although foamed plastic contributes importantly to the marine environmental pollution, there is generally limited knowledge of the composition of this litter pool. The aim of this study was to characterize item types and polymer materials of foamed litter from six Danish reference beaches during the period 2018-2021. The foamed litter were classified into ten categories, including identifiable items, as well as fragments of foamed PS, or pieces of other foamed polymers of rigid or flexible sponges. Foamed PS (42%) and PUR (49%) were identified as the dominant polymers by FTIR analysis. Multivariate exploratory analysis was performed to investigate PUR foam, and specific spectra features for rigid and flexible foam were demonstrated. Furthermore, we assessed different correlation methods for identification of PUR foams.

Effect of particle size on the colonization of biofilms and the potential of biofilm-covered microplastics as metal carriers

Upon release into the aquatic environment, the surface of microplastics (MPs) can be readily colonized by biofilms, which may enhance the adsorption of contaminants. In this study, industrial-grade polystyrene (PS) of about 4 mm in size (MP4000-1), food-grade PS of about 4 mm in size (MP4000-2), and Powder PS of about 75 μm in size (MP75) were co-cultured with a model freshwater fungus, namely Acremonium strictum strain KR21-2, for seven days to form biofilms on their surface. We also determined the changes in surface physicochemical properties of the biofilm-covered MPs (BMPs) and the heavy metal adsorption capacity of the original MPs and BMPs. The results revealed that the biofilms improve the adsorption of heavy metals on MPs, and the particle size of MPs plays a crucial role in biofilm colonization and adsorption of heavy metals by BMPs. MP75 can carry more biofilm on its surface than that of the two MP4000s and form heteroaggregates with biofilms. In addition, there were more functional groups on the surface of BMP75 than on the surface of the two BMP4000s, which could promote the electrostatic interaction and chemical association of heavy metals. Moreover, BMP75 exhibited a higher capacity to adsorb Cu and reduce Cr (VI), which may be related to the functional groups in its biofilm. Overall, this study showed that after biofilms colonization, BMPs of smaller size have more significant potential as a metal vector, and the particle size deserves more scientific attention during the risk assessment.

Microplastics in the Deep: Comparing Dietary and Plastic Ingestion Data between Two Mediterranean Bathyal Opportunistic Feeder Species, Galeus melastomus, Rafinesque, 1810 and Coelorinchus caelorhincus (Risso, 1810), through Stomach Content Analysis

Marine plastic pollution is currently an issue of mounting concern around the world. Stomach content of marine fish has been increasingly used as a valid proxy for detecting the presence of such a pollutant in marine biota, both for coastal and deep-water environments. Although ingestion of microplastics has been reported in an increasing number of species, the patterns of ingestion still remain unclear, depending closely on the interaction between the species and types of microplastics involved. In this context, we analysed and compared the stomach contents of two bathyal dwelling opportunistic feeder species namely Galeus melastomus and Coelorinchus caelorhincus. In particular, we analysed microplastic items according to their dimension, morphology and colour, and diet’s variation with size obtained through prey identification. Both species showed a higher frequency of occurrence of the blue filament-like middle-sized microplastics (1.01–4.75 mm) compared with the other categories, although this pattern was much more marked in C. caelorhincus than in G. melastomus. The latter conversely showed a larger array of ingested plastic items in terms of shape and colour. Matching plastic ingestion with dietary data suggested potential predator confusion occurring in C. caelorhincus through active mis-selection of a defined type of microplastic instead of some particular family of polychaetes, which resemble in shape, size, and color to that type. Otherwise, G. melastomus appeared more prone to a random ingestion of a larger array of microplastic items because of a more generalistic and less selective feeding strategy. Although further validation is needed, stomach contents of the two species showed evidence strong enough to be considered as potential bioindicator species of microplastic pollution, as required by the Marine Strategy Framework Directive for monitoring this pollutant in the marine environment.

Fate of plastic in the environment: From macro to nano by macrofauna

Plastic ingestion has been widely investigated to understand its adverse harms on fauna, but the role of fauna itself in plastic fragmentation has been rarely addressed. Here, we review and discuss the available experimental results on the role of terrestrial and aquatic macrofauna in plastic biofragmentation and degradation. Recent studies have shown how biting, chewing, and stomach contractions of organisms shatter ingested plastic along their digestive tracts. Gut microbial communities can play a role in biodegradation and their composition can shift according to the type of plastic ingested. Shifts in molecular weights, chemical bond forming and breaking, and changes in thermal modification detected in the plastic debris present in the faeces also suggest active biodegradation. A few studies have also shown interactions other than ingestion, such as burrowing, may actively or passively promote physical plastic fragmentation by fauna. We suggest that further investigations into the role of fauna in physical fragmentation and chemical degradation linked to active ingestion and gut associated microbiota metabolism, respectively, should be conducted to better evaluate the impact of these mechanisms on the release of micro- and nano-plastic in the environment. Knowledge on macrofauna other than marine invertebrates and terrestrial soil dwelling invertebrates is particularly lacking, as well as focus on broader types of plastic polymers.

Baseline Marine Litter Surveys along Vietnam Coasts Using Citizen Science Approach

Marine litter is a significant threat to the marine environment, human health, and the economy. In this study, beach litter surveys along Vietnamese coasts were conducted in a local context to quantify and characterize marine litter using the modified GESAMP marine litter monitoring guideline. A total of 21,754 items weighing 136,820.2 g was recorded across 14 surveys from September 2020 to January 2021. Plastic was the most abundant type of litter by both quantity (20,744 items) and weight (100,371.2 g). Fishing gear 1 (fishing plastic rope, net pieces, fishing lures and lines, hard plastic floats) and soft plastic fragments were the most frequently observed items (17.65% and 17.24%, respectively). This study not only demonstrates the abundance and composition of marine litter in Vietnam, it also provides valuable information for the implementation of appropriate preventive measures, such as the redesign of collection, reuse, and recycling programs, and informs policy and priorities, with a focus on action and investment in Vietnam. Moreover, insights from this study indicate that citizen science is a useful approach for collecting data on marine litter in Vietnam.

A Meta-Analysis of the Characterisations of Plastic Ingested by Fish Globally

Plastic contamination in the environment is common but the characterisation of plastic ingested by fish in different environments is lacking. Hence, a meta-analysis was conducted to identify the prevalence of plastic ingested by fish globally. Based on a qualitative analysis of plastic size, it was determined that small microplastics (<1 mm) are predominantly ingested by fish globally. Furthermore, our meta-analysis revealed that plastic fibres (70.6%) and fragments (19.3%) were the most prevalent plastic components ingested by fish, while blue (24.2%) and black (18.0%) coloured plastic were the most abundant. Polyethylene (15.7%) and polyester (11.6%) were the most abundant polymers. Mixed-effect models were employed to identify the effects of the moderators (sampling environment, plastic size, digestive organs examined, and sampling continents) on the prevalence of plastic shape, colour, and polymer type. Among the moderators, only the sampling environment and continent contributed to a significant difference between subgroups in plastic shape and polymer type.

Microplastics in a pelagic dolphinfish (Coryphaena hippurus) from the Eastern Pacific Ocean and the implications for fish health

Microplastic pollution in fish is a growing concern worldwide due to its implication for human health. Microplastic contaminations and impacts were investigated in 15 wild-caught commercially important dolphinfish (Coryphaena hippurus L.) from the Eastern Pacific Ocean waters. 1741 suspected particles were extracted from gills, esophagus, stomachs, intestinal tracts, and muscle of C. hippurus. Only 139 of them were identified as microplastics by microscopic inspections and micro-Raman spectroscopic analysis. 10, 34, 51, 35, and 9 out of these 139 microplastic particles were extracted from the gill, esophagus, stomach, intestinal tract, and muscle respectively. Overall, microplastics were detected in 15 out of 15 fish (100%), with ~9.3 pieces per individual on average. The prevalence and high incidence of occurrence of microplastics in the C. hippurus suggest that this pelagic species are at high risk of exposure to microplastic pollutions. The chemical composition of microplastics was made of polyester (PES, 46.8%), polyethylene terephthalate (PET, 38.1%), polypropylene (PP, 7.9%), polystyrene (PS, 5.0%), polyethylene-polypropylene copolymer (PE-PP, 1.4%), and polyethylene (PE, 0.7%). 36.7% and 13.7% of microplastics in the fish were 1-2.5 mm and 2.5-5 mm, respectively. Microplastics of 0.1-0.5 mm and 0.5-1 mm roughly shared equally the remaining 50%. Molecular docking results implied that interaction of the four dominant microplastic polymers (PES, PET, PP, and PS) with cytochrome P450 17A1 would lead to impairment of the reproductive function of C. hippurus. The findings provide insights on the harms from microplastic exposure, along with quantitative information of occurrence, abundance, and distribution of microplastics in the fish tissues, which will ultimately improve understanding of bioavailability and hazards of microplastics to the organisms and beyond to human via food chain transfer.

Incidence of plastic ingestion by the shortfin mako, Isurus oxyrinchus, off the northeast coast of Taiwan

This present study documents the incidence of plastic digestion by shortfin mako shark (Isurus oxyrinchus), caught by the Taiwanese small-scale tuna longline fishery in the Northwest Pacific Ocean (between the northeast coast of Taiwan and Japan). In 20 stomachs of shortfin mako, nearly 10% of samples contained at least one piece of plastic debris. The ingested plastic debris was found in the forms of films (5.0 cm) and fragments (3.0 mm) and was identified as polypropylene (PP) based on its polymer characteristics. The results from the analysis provide evidence for the anthropogenic origin and potential intake pathway of direct engulfment of ingested plastics. Our results also confirmed the low incidence of plastic ingestion in shortfin mako, suggesting that pelagic marine species may be relatively less affected by plastic pollution. Future research efforts are thus needed to assess the long-term impact of plastic pollution on marine species.

Ecotoxicological and physiological risks of microplastics on fish and their possible mitigation measures

Microplastics (MPs) are widely distributed and extensively found within marine ecosystems, and approximately 8 million tons of plastics are being dumped into the sea annually. Once reached the marine environment, plastics tend to get fragmented into smaller particles through photo-degradation, mechanical and biological processes. These MPs have raised concerns globally due to their potential toxic impacts on a wide variety of aquatic fauna and humans. Ingested microplastics can cause severe health implications in fishes, including reduced feeding intensity, improper gill functioning, immuno-suppression, and compromised reproducibility. Several studies were also conducted to scrutinize MPs trophic transfer through the food chain from primary producers to top predators and their bioaccumulation. This paper briefly summarizes all the possible sources, routes, bioavailability, trophic transfer, and consequences of microplastics in fishes. The review article also intended to highlight various mitigation strategies like implementing Four R's concept (refuse, reduce, reuse, and recycle), integrated strategies, ban on single-use plastics, use bioplastics, and create behavioural changes with public awareness.

Evidence of microplastic ingestion by cultured European sea bass (Dicentrarchus labrax)

The presence of microplastics (MPs) in the marine environment is a concerning topic due to the ecotoxicological effects and possible seafood contamination. Data is needed to evaluate human exposure and assess risks, in the context of a healthy and beneficial seafood consumption. While microplastic ingestion by wild fish has been reported since the early 70's, farmed fish are rarely investigated. Here, for the first time the presence of microplastics in fish cultivated in the coastal water of Tenerife (Canary Island, Spain) was evaluated. From 83 examined individuals, 65% displayed microplastics in their gastrointestinal tracts, with averages between 0.6 ± 0.8 (SD) and 2.7 ± 1.85 (SD) particles per fish. The total number of microplastics detected was 119. Fibres (81%) and fragments (12%) were the predominant shapes. FTIR analysis showed that fibres were mostly composed by Cellulose (55%) and Nylon (27%), whereas fragments by PE (25%) and PP (25%).

Review of the artificially-accelerated aging technology and ecological risk of microplastics

After being discarded into the environment, the microplastics (MPs) will undergo weathering effects. However, the low degradation rate of MPs in natural processes greatly limits the understanding of long-term aging behavior. By critically reviewing 82 articles in Web of Science from 2015 to 2020, the paper summarized different laboratory technologies including light irradiation, chemical oxidation, heat treatment and γ-ray irradiation to simulate and accelerate the aging of MPs, and evaluated the feasibility by comparison with natural processes. The advantages of laboratory technologies are that aging conditions can be artificially controlled and that the labor and time costs can be saved, whereas the laboratory system is too simple to simulate complex aging processes in the environment. We further reviewed the potential impacts of aging process on the risks of MPs (i.e. physical injury, combined toxicity with external pollutants and chemical risk of additives and low-molecular products). The overall risks are seemingly enhanced by aging process due to the high ingestion by organisms, the strong interaction with pollutants and the release of MP-derived organic compounds. Further studies on the aging behavior of MPs should be focused on the laboratory techniques that can simulate multiple processes of natural aging, the long-term fragmentation behavior of MPs, the effect of aging on growth rate of biofilm in MPs and ingestion property by organisms, and the relationship between aging property of MPs and release rate of chemicals in leachates.

Effect of microplastics and arsenic on nutrients and microorganisms in rice rhizosphere soil

The presence of microplastics and arsenic in soil can endanger crop growth; therefore, their effects on the properties of rhizosphere soil should be evaluated. Large (10-100 µm) and small (0.1-1 µm) polystyrene (PSMP) and polytetrafluorethylene (PTFE) particles were added to soil with different arsenic concentrations (1.4, 24.7, and 86.3 mg kg^-1) to investigate the combined effect of microplastics and arsenic pollution on rice rhizosphere soil. After the addition of PSMP and PTFE, pH, arsenic (V) and arsenic (III) in the soil were observed to decrease. The interaction of arsenic with PSMP and PTFE resulted in this phenomenon, leading to a decrease of arsenic bioavailability in the soil. PSMP, PTFE, and arsenic reduced the abundance of Proteobacteria, increased the abundance of Chloroflexi and Acidobacteria, and inhibited soil urease, acid phosphatase, protease, dehydrogenase, and peroxidase activity via affecting the tertiary structure of the enzyme. PSMP, PTFE, and arsenic also reduced the available nitrogen and phosphorus content in the soil. Arsenic increased the soil organic matter content, whereas PSMP and PTFE reduced the organic matter content. Furthermore, microplastics inhibited the effects of arsenic on the microbial and chemical properties of the rhizosphere soil. This study revealed the effects of microplastic and arsenic pollution on rice rhizosphere microorganisms and nutrients, and elucidated the mechanism by which these pollutants retard crop growth in the designed growth medium.

Ingestion of plastic debris by commercially important marine fish in southeast-south Brazil

Rising concentrations of plastics in the oceans are leading to increasing negative interactions with marine biota, including ingestion by endangered and/or economically important seafood species such as fish. In this paper, we visually evaluated plastic debris ingestion by 965 specimens of eight commercially exploited fish species from different marine habitats off the southeast-south coast of Brazil. All species ingested plastics, with pelagic animals having higher amounts, frequency of occurrence, diversity and sizes of ingested items than demersal-pelagic and demersal animals. Highest frequency of occurrence (FO%) of plastic ingestion (25.8%) was observed for the pelagic skipjack tuna Katsuwonus pelamis (Scombridae), and lowest (5%) for the demersal bluewing searobin Prionotus punctatus (Triglidae). Microplastics predominated in all species, and fibers/lines and fragments were the main items found, possibly derived from fishing materials. The most abundant plastic colors were transparent, black and blue, and the most common polymers were polyamide and polyurethane. With the available data, no relationship between the size of the individuals and amount of ingested plastics was observed. Considering the negative impacts of plastic ingestion on marine fish, and potentially on human health due to their consumption, understanding ingestion patterns is critical for better evaluating their origin and possible causes, and consequently for helping define prevention strategies for this problem.

The mechanism of polystyrene microplastics to affect arsenic volatilization in arsenic-contaminated paddy soils

Different concentrations and sizes of polystyrene microplastics (PS-MP) were added to low (25.9) and high (56.8) mg kg^-1 As-contaminated soil to investigate the effects of PS-MP on soil As volatilization. Either S₁ (10 μm) or S₂ (0.1-1 μm) PS-MP was added to As-contaminated soil at 0.8%, which increased As volatilization by 13.7% and 7.4% in low As-contaminated soil; and 21.8% and 16.5% in high As-contaminated soil, respectively. The addition of PS-MP reduced the water-soluble (WS) As content, increased the non-specifically-sorbed (NSS), specifically-sorbed (SS) As content, soil catalase (CAT) and urease (UE) activities. The abundance of Proteobacteria and Firmicutes showed opposite trends to As volatilization, while the abundance of Bacteroidetes and arsM gene expression exhibited similar variability to As volatilization over the 7-week experiment. Therefore, we postulate that in As-contaminated soil, As volatilization was enhanced in the presence of PS-MP due to two possible mechanisms: 1) PS-MP affects the abundance of Proteobacteria, Firmicutes, Bacteroidetes, and arsM gene in soil; 2) PS-MP increases As volatilization via reducing soil nutrient and increasing the content of SS As. Our results highlighted the importance of investigating impacts of microplastics on the volatility of specific contaminants to implement effective environmental remediation strategies in polluted farmlands.

Land or sea? What bottles tell us about the origins of beach litter in Kenya

Identifying the source of marine litter is essential to design effective mitigation measures to reduce plastic leakage into marine ecosystems. Kenya recently banned the use of polyethylene bags, but PET drink bottles remain a contentious source of litter in the country. I collected bottles and other single-use containers at nine Kenyan beaches, and compared their composition, country of manufacture and approximate age (time since manufacture) to bottles collected in coastal towns. Locally manufactured bottles dominated street litter (98%) and on urban beaches (93%) but became increasingly uncommon with distance from coastal towns, comprising only 30% of bottles at remote beaches. These steep spatial gradients indicate that most local bottles do not disperse far from source areas. The presence of lids is important for long-distance dispersal of glass and PET bottles, and many PET bottles littered in urban areas lack lids. HDPE bottles are much more common on beaches than on streets, and most come from Indonesia. The presence of epibionts and bite marks suggest that most HDPE bottles have drifted in the South Equatorial Current from southeast Asia, whereas foreign PP bottles mostly come from Indian Ocean island states. Reducing plastic leakage in southeast Asia should reduce the amount of beach litter throughout the western Indian Ocean. Some foreign PET bottles come from neighbouring states, but many are probably dumped illegally from ships operating from Asia. In addition to reducing plastic leakage from land-based sources, we need to ensure compliance with MARPOL Annex V regulations banning the disposal of plastic wastes at sea.

3D hotspots of marine litter in the Mediterranean: A modeling study

The 3D dispersion of marine litter (ML) over the Mediterranean basin has been simulated using the velocity fields from a high resolution circulation model as base to run a 3D Lagrangian model. Three simulations have been performed to mimic the evolution of ML with density lower, similar, or higher than seawater. In all cases a realistic distribution of ML sources was used. Our results show that the accumulation/dispersion areas of the floating and buoyancy neutral particles are practically the same, although the latter are distributed in the water column, 80% of them found in the photic layer (average depth of 35m). Regarding to the densest particles, they rapidly sink and reach the seafloor close to their source. The regions of higher temporal variability mostly coincide with the ML accumulation regions. Weak seasonal variability occurs at a sub-basin scale as a result of the particles redistribution induced by the seasonal variability of the current field.

Characterisation of an unexplored group of microplastics from the South China Sea: Can they be caused by macrofaunal fragmentation?

Research on plastics fragmentation is important for the estimation of amount of microplastics but the biological causes for fragmentation have not been acknowledged. From microplastics collected in the beaches of Hong Kong, we revealed an abnormal type of fragment which has not been reported before. These fragments, composing about 6% of the microplastics (pellet, foam, bead, fragment) collected, were interestingly triangular in shape with at least two of the three sides being characteristically straight and resembling a cut made by compression. Objective observations have distinguished these "trimmed triangular fragments" to those triangular fragments that were fractured randomly. By comparing with additional evidence, we proposed that these trimmed fragments were the daughter pieces of macrofaunal biting. If this was so, there would be wide implications on fragmentation modeling studies for microplastics since active biting of large plastic debris has generally not been considered as a factor of plastics fragmentation.

Toward an Improved Understanding of the Ingestion and Trophic Transfer of Microplastic Particles: Critical Review and Implications for Future Research

Microplastic particles have been observed in the environment and routinely detected in the stomachs and intestines of aquatic organisms over the last 50 yr. In the present review, information on the ingestion of plastic debris of varying sizes is collated, including data for >800 species representing approximately 87 000 individual organisms, for which plastic debris and microplastic particles have been observed in approximately 17 500, or 20%. The average reported number of microplastic particles/individual across all studies is estimated to be 4, with studies typically reporting averages ranging from 0 to 10 particles/individual. A general observation is that although strong evidence exists for the biological ingestion of microplastic particles, they do not bioaccumulate and do not appear to be subject to biomagnification as a result of trophic transfer through food webs, with >99% of observations from field-based studies reporting that microplastic particles are located within the gastrointestinal tract. Overall, there is substantial heterogeneity in how samples are collected, processed, analyzed, and reported, causing significant challenges in attempting to assess temporal and spatial trends or helping to inform a mechanistic understanding. Nevertheless, several studies suggest that the characteristics of microplastic particles ingested by organisms are generally representative of plastic debris in the vicinity where individuals are collected. Monitoring of spatial and temporal trends of ingested microplastic particles could thus potentially be useful in assessing mitigation efforts aimed at reducing the emission of plastic and microplastic particles to the environment. The development and application of standardized analytical methods are urgently needed to better understand spatial and temporal trends. Environ Toxicol Chem 2020;39:1119-1137. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Histological, enzymatic and chemical analyses of the potential effects of differently sized microplastic particles upon long-term ingestion in zebrafish (Danio rerio)

In microplastics (MPs) research, there is an urgent need to critically reconsider methodological approaches and results published, since public opinion and political decisions might be based on studies using debatable methods and reporting questionable results. For instance, recent studies claim that MPs induce intestinal damage and that relatively large MPs are transferred to, e.g., livers in fish. However, there is methodological criticism and considerable concern whether MP transfer to surrounding tissues is plausible. Likewise, there is an ongoing discussion in MP research if MPs act as vectors for adsorbed hazardous chemicals. In this study, effects of very small (4-6 μm) and very large (125-500 μm) benzo(a) pyrene (BaP)-spiked polyethylene (PE) particles administered via different uptake routes (food chain vs. direct uptake) were compared in a 21-day zebrafish (Danio rerio) feeding experiment. Particular care was taken to prevent cross-contamination of MPs during dissection and histological sample preparation. In contrast to numerous reports in literature describing similar approaches, independent of exposure route and MP size, no adverse effects could be detected. Likewise, no BaP accumulation could be documented, and MPs were exclusively seen in the lumen of the intestinal tract, which, however, did not induce any histopathological effects. Results indicate that in fish MPs are taken up, pass along the intestinal lumen and are excreted without any symptoms of adverse effects.

Effect of weathering on environmental behavior of microplastics: Properties, sorption and potential risks

Microplastic (MP) pollution is a raising global concern in recent years due to its wide distribution. Additionally, most of the MPs have undergone extensive weathering in the environment, and weathered MPs may exhibit different physicochemical properties from pristine ones. The review reveals the change in physicochemical properties (e.g. size, color, crystallinity, mechanical property and oxygen-containing groups) and the release of additives and MP-derived intermediates (i.e. oligomers and oxygenated compounds) during weathering processes. Weathering further affects the sorption behavior of MPs for environmental pollutants because of the changed crystallinity, specific surface area and oxygen functional groups. The interaction mechanisms of pristine and weathered MPs with pollutants are summarized, and how weathering processes affect sorption behavior is critically revealed. Because of the changed size, color and surface charges, weathered MPs might be ingested by aquatic organisms in different ways from the pristine ones. The detailed effects of weathering on the ingestion of MPs are discussed, and the potential toxicity of leachates from weathering processes is evaluated. In addition, the environmental components (e.g. natural organic matter and salinity) and biofilm correlated to the sorption behavior of MPs are reviewed. As for the knowledge gap, further studies should focus on the long-term weathering of MPs and the relationships between weathering properties and sorption capacities toward pollutants. The potential risks of weathered MPs and leachates on organisms should be explored.

Physical interactions between marine phytoplankton and PET plastics in seawater

Plastics are the most abundant marine debris globally dispersed in the oceans and its production is rising with documented negative impacts in marine ecosystems. However, the chemical-physical and biological interactions occurring between plastic and planktonic communities of different types of microorganisms are poorly understood. In these respects, it is of paramount importance to understand, on a molecular level on the surface, what happens to plastic fragments when dispersed in the ocean and directly interacting with phytoplankton assemblages. This study presents a computer-aided analysis of electron paramagnetic resonance (EPR) spectra of selected spin probes able to enter the phyoplanktonic cell interface and interact with the plastic surface. Two different marine phytoplankton species were analyzed, such as the diatom Skeletonema marinoi and dinoflagellate Lingulodinium polyedrum, in absence and presence of polyethylene terephthalate (PET) fragments in synthetic seawater (ASPM), in order to in-situ characterize the interactions occurring between the microalgal cells and plastic surfaces. The analysis was performed at increasing incubation times. The cellular growth and adhesion rates of microalgae in batch culture medium and on the plastic fragments were also evaluated. The data agreed with the EPR results, which showed a significant difference in terms of surface properties between the diatom and dinoflagellate species. Low-polar interactions of lipid aggregates with the plastic surface sites were mainly responsible for the cell-plastic adhesion by S. marinoi, which is exponentially growing on the plastic surface over the incubation time.

Plastic Particle Ingestion by Wild Freshwater Fish: A Critical Review

Plastic pollution, especially microplastics (MP) pollution, is a hot topic in both mainstream media and scientific literature. Although rivers are potentially the major transport pathway of this pollution to the sea, plastic contamination in freshwater bodies is comparatively understudied. Microplastic pollution in freshwater fish is of growing interest, and while few studies exist, discrepancies do occur in the sampling, extraction, and identification of MP and in the expression of the results. Even though those differences hamper comparisons between some studies, a comparative work has been performed to identify the factors influencing MP ingestion by fish and consequently to target potential ecological traits that can be used to monitor species. Monitoring plastic ingested by fish will give relevant ecological information on MP pollution. This review focuses on MP ingestion by wild freshwater and estuarine fish. In addition to providing an overview of the existing data concerning contamination levels in wild freshwater fish, we aimed to (1) propose several overall recommendations on the methodologies applicable to all biota, (2) compare MP contamination levels in fish and in their environment, and (3) determine which parameters could help to define fish species for monitoring.

Fish and Seabird Gut Conditions Enhance Desorption of Estrogenic Chemicals from Commonly-Ingested Plastic Items

Plastic is ingested by over 100 bird species and 40 fish species. Once ingested, plastic may release endocrine-disrupting plastic additives in the animal; however, amounts transferred are poorly characterized. We exposed 16 commonly ingested plastic items to fish and seabird laboratory gut mimic models using the digestive enzyme pepsin at pH 2 and shook them for 16 h at either 28 °C (in saltwater) for fish or 40 °C (in freshwater) for seabirds. Gut liquid was then evaluated for estrogen receptor activity using an in vitro cell line, and plastic-additive concentrations were quantified using ultrahigh-performance liquid chromatography/tandem mass spectrometry. Both seabird ( p < 0.0001) and fish gut conditions ( p < 0.0001) significantly enhanced the biological estrogenicity of expanded polystyrene, polyethylene shopping bag, and polypropylene string relative to controls, resulting in up to a 10.6-fold increase in estrogenicity. Out of 12 plastic additives analyzed, bisphenol A (BPA) (204 ± 129%) and diethylhexyl phthalate (DEHP) (175 ± 97%) concentrations were significantly increased in seabird gut conditions relative to control and butylbenzyl phthalate (BBP) (132 ± 68%) was significantly increased in fish gut conditions relative to control. BPA, DEHP, and BBP did not adequately account for the increase in biological estrogenicity, suggesting that uncharacterized plastic additives may have been enhanced by gut conditions.

Assessing the citizen science approach as tool to increase awareness on the marine litter problem

This paper provides a quantitative assessment of students' attitude and behaviors towards marine litter before and after their participation to SEACleaner, an educational and citizen science project devoted to monitor macro- and micro-litter in an Area belonging to "Pelagos Sanctuary" (Mediterranean Sea). This approach produced interesting outcomes both for the research sector of marine pollution and environmental monitoring, as well for the scientific and environmental education. Here we focus on citizen science as an effective vector for raising young people awareness of marine litter and fostering sound behaviors. A specially designed questionnaire was administered to 87 High School students, to test the validity of such approach. The results state that the students change quantitatively their perception of beach-litter causes and derived problems, and they improved their knowledge about the main marine litter sources and the role of the sea in the waste transport and deposition along the coast.

Zebrafish can recognize microplastics as inedible materials: Quantitative evidence of ingestion behavior

This study investigated the ingestion behavior of zebrafish exposed to microplastic particles (MPs) at different concentrations, presented alone or in a mix with food particles. Zebrafish showed spitting behavior after ingesting micro-sized (247.5 μm) polyethylene particles (i.e., MPs), with prey-capture time increasing when food and MPs were supplied simultaneously. Fish were compelled to ingest MPs with food, and the accumulation percentage (ingested particles/supplied particles) was quantified as 0.5 to 9.4% with increasing food volume. However, the accumulation percentage was determined as 0.0 to 1.0% under exposure to MPs only, and as 3.8 to 4.3% at high MP concentrations when the food concentration was fixed. Overall, these results demonstrate that small freshwater organisms can recognize that MPs are not food items. Under laboratory conditions, zebrafish rarely discriminate between food and MPs when both are presented together, and the indiscriminate feeding behavior becomes clearer as more food is available.

Plastic waste as a significant threat to environment - a systematic literature review

Context Materials which exceed the balance of their production and destruction lead to the deterioration in the environment. Plastic is one such material which poses a big threat to the environment. A huge amount of plastic is produced and dumped into the environment which does not readily degrade naturally. In this paper, we address the organization of a large body of literature published on the management of waste plastics being the most challenging issue of the modern world. Objectives To address the issue of the management of waste plastics, there is a dire need to organize the literature published in this field. This paper presents a systematic literature review on plastic waste, its fate and biodegradation in the environment. The objective is to make conclusions on possible practical techniques to lessen the effects of plastic waste on the environment. Method A systematic literature review protocol was followed for conducting the present study [Kitchenham B, Brereton OP, Budgen D, Turner M, Bailey J, Linkman S. Systematic literature reviews in software engineering - A systematic literature review. Inf Softw Technol 2009;51(1):7-15.]. A predefined set of book sections, conference proceedings and high-quality journal publications during the years 1999 to September 2017 were used for data collection. Results One hundred and fifty-three primary studies are selected, based on predefined exclusion, inclusion and quality criteria. These studies will help to identify the fate of different waste plastics, their impact and management and the disposal techniques frequently used. The study also identifies a number of significant techniques and measures for the conversion of waste plastic materials into useful products. Conclusion Five fundamental strategies are used for the handling of plastic waste. These strategies include: recycling, depositing in landfill, incineration, microbial degradation and conversion into useful materials. All of these methods have their own limitations, due to which there is need to explore the studies for optimum solutions of the management of plastics waste.