High Concentrations Of Microplastics Research Articles

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 (333-335μm) are readily reported in the literature on microplastics, we used a finer plankton net (100μm) to determine the proportion of captured microplastics smaller than 300μm. 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 300μm 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.

The Analysis of the Mycobiota in Plastic Polluted Soil Reveals a Reduction in Metabolic Ability.

Plastic pollution is a growing environmental issue that results in its accumulation and persistence in soil for many decades, with possible effects on soil quality and ecosystem services. Microorganisms, and especially fungi, are a keystone of soil biodiversity and soil metabolic capacity. The aim of this research was to study soil fungal biodiversity and soil microbial metabolic profiles in three different sites in northern Italy, where macro- and microplastic concentration in soil was measured. The metabolic analyses of soil microorganisms were performed by Biolog EcoPlates, while the ITS1 fragment of the 18S ribosomal cDNA was used as a target for the metabarcoding of fungal communities. The results showed an intense and significant decrease in soil microbial metabolic ability in the site with the highest concentration of microplastics. Moreover, the soil fungal community composition was significantly different in the most pristine site when compared with the other two sites. The metabarcoding of soil samples revealed a general dominance of Mortierellomycota followed by Ascomycota in all sampled soils. Moreover, a dominance of fungi involved in the degradation of plant residues was observed in all three sites. In conclusion, this study lays the foundation for further research into the effect of plastics on soil microbial communities and their activities.

Microplastic contamination in coastal waters of South Larompong, Luwu, South Sulawesi, Indonesia

Microplastic contamination in the aquatic environment poses a serious threat to the survival of the ecosystem because it is persistent. This study aims to analyze the concentration of microplastics in the water column in the coastal waters of South Larompong. Sampling was carried out using the volume reduce method with the neuston net at four stations, namely Bonepute Beach, Ponnori Beach, Babana Beach and Damaci Beach. The results showed that there was microplastic contamination and found as many as 386 microplastic particles with an average concentration of 2.68 particles/m3. The results of the analysis of microplastic concentrations showed significant differences (P<0.05) between stations. The highest concentrations of microplastics are found on Bonepute Beach which is an area of aquaculture, fishing and densely populated settlements, then followed by Ponnori Beach which is a tourist area. Meanwhile, the lowest microplastic concentrations are found on Babana Beach, which is the estuary area of the Temboe River and Damaci Beach which is a nearby area. Several forms of microplastics were found, namely granules, fibers, films and fragments which were the most dominant forms. Several colors of microplastics were found, namely blue, brown, green, red, white, and black which were the most dominant colors. There are two types of polymer found, namely HDPE (High Density Polyethylene) and PVA (Polyvinyl alcohol). The conclusion of this study is that the coastal waters of South Larompong have been contaminated with microplastics so that more attention is needed regarding the handling of plastic waste, especially microplastics.

The fate of microplastics in wastewater treatment plants: An overview of source and remediation technologies

Microplastics (MPs) in everyday consumer products have paved the way for high MPs concentrations in wastewater. Wastewater treatment plants (WWTP)s are the significant focal points for MP pollution, as millions of MP particles with varying characteristics enter WWTPs through the sewage systems of urban areas. Although the units in the WWTPs are not primarily designed to target MPs specifically, researchers have reported a large amount of microplastic removal from various units of WWTPs. The scientific community has remarkably studied various conventional and advanced treatment methods to remediate MPs and nanoplastics (NPs) from wastewater. This review aims to provide comprehensive knowledge about the source of MPs and NPs in wastewater, their composition, toxic effects, and remediation from treatment units of the WWTPs. The WWTPs comprise several physical, chemical, and biological treatment processes broadly categorized into three key stages: primary, secondary, and tertiary. The interaction of MPs and NPs with these processes have also been reviewed. Literature indicates that the WWTPs can separate more than 90% of MPs from wastewater. However, despite low concentrations of MPs in the treated effluent, large discharge volumes contribute to millions of MPs/NPs into the environment. Also, the separated MPs/NPs re-enter the environment through sludge applied on land. The paper also discusses the application of various advanced wastewater treatment technologies and their efficacies in remediating microplastics. Finally, the paper also highlights the research gaps where additional exploration is required, providing a new perspective on developing policies for controlling microplastic pollution.

Characterization and removal of microplastics in a sewage treatment plant from urban Nagpur, India.

Sewage treatment plant (STP) acts as a potential source of microplastic contamination in the environment. The presence of microplastics in the sewage treatment plant is reported over the globe in varying concentrations. Hence, the current study is intended to evaluate the presence and abundance of microplastics occurring in sewage treatment plants in India. The samples were processed through digestion and density separation, followed by microscopic and polymer identification through Fourier transform infrared spectroscopy. Also, different wastewater parameters were studied to analyze their influence. High microplastic concentrations were detected in the influent (1860 ± 265MPs/L), which reduced by > 90%, to around 148 ± 51MPs/L in the effluent. The concentration of microplastics in sewage sludge was 830MPs/kg. The prominent plastic types identified include low-density polyethylene, polypropylene, polyurethane, polyvinyl chloride, and rayon. The smaller particles prevail in the effluent, releasing around 30 billion particles per day to the environment. This suggests that the current STP is efficient in removing the majority of the particles, but considerations are needed to avoid the ecological risks associated.

Effects of Microplastics on Growth and Physiological Characteristics of Tobacco (Nicotiana tabacum L.)

The environmental effects caused by the proliferation of microplastics have received extensive attention. However, at this stage, there is a lack of research on the toxicology of microplastics and their impacts on plants. This study explored the effects of microplastics on the growth and physiological characteristics of tobacco. Using tobacco (Nicotiana tabacum L.) variety Yunyan87 and low-density polyethylene (LDPE, 13 μm particle size), different concentrations, which were 0 mg/L (CK), 10 mg/L (T1), 100 mg/L (T2), and 1000 mg/L (T3), were subjected to hydroponic experiments to study the effects of microplastics on the growth and physiological characteristics of tobacco. The results showed that microplastics had a certain inhibitory effect on the growth of tobacco. Among them, high concentrations of microplastics significantly inhibited the root architecture and growth characteristics. According to the performance observed with different treatments, the content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) increased in the medium and high concentrations. In addition, the changes in catalase (CAT) and peroxidase (POD) activity were not obvious. Experiments showed that microplastics could significantly inhibit the growth and development of tobacco and reduce the accumulation of aerial parts and root biomass.

THE EVALUATION OF MICROPLASTIC PARTICLES IN THE WATER AREA OF LAKE LADOGA

In this article, we present the results of studying the content of microplastics in the surface layer of water column and sediments in the water area of Lake Ladoga. The sampling, preparing and analysis were carried out in 2018-2021. We used NOAA methods adapted for freshwater bodies to prepare sediment samples and extract microplastics from sediments. An optical microscope was used to identify shape, size and colour of microplastic particles. The chemical analysis of studied particles was carried out using methods of Raman spectrometry. The results showed that microplastic particles are present in all samples. The highest concentrations of microplastics were fixed near urban districts (Priozersk and Sortavala) and industrial areas (the plant in the city of Pitkyaranta). The increased concentrations were also observed in the areas of river inflows (the Vuoksi, the Jänisjoki and the Volkhov rivers). Regarding the shape, fibers prevailed to a large extent (97%). The largest number of particles by size were found within the range of 60-1000 µm (60%), the number of particles decreased with increasing of their size. The statistically significant correlation between the particle-size composition of sediments and concentrations of microplastic particles in these sediments was not found. The spectral analysis of chemical composition of particles showed that the most common types of microplastics in the water area of the Ladoga were polyamide and polyethylene; polyethylene terephthalate and polycarbonate particles were also found. Apart from the plastic particles, a large number of cotton fibers were fixed.

The Effect of Different Storage Conditions for Refilled Plastic Drink Bottles on the Concentration of Microplastic Release in Water

The demand for water consumption in plastic bottles has increased in recent years. Most consumers of this type of water think that it is well sterilized. This is due to the high level of propaganda that accompanies its production regarding the extent of its validity. It is also common to reuse these bottles for several times by filling it frequently for different uses, and their use for preserving and storing different types of liquids.
 This study is conducted for the purpose of detecting and evaluating the pollution caused by microplastics in plastic bottles filled with water for one time, as well as water bottles reused more than once. Moreover, it evaluates the effect of storage period and conditions on the abundance of microplastics when bottles are stored for different times and under the influence of different conditions (shade, cooling and freezing). The results of the study show the presence of fine microplastics in open bottled water exposed to different storage conditions. The highest concentration of microplastics is obtained in storage conditions under the influence of shade with a limit of (1050) microplastics / liter, while the lowest concentration is obtained at around (20) microplastics / liter. The highest concentration of microplastics is obtained in storage conditions under the influence of cooling, with a limit of (850) microplastics / liter, whereas, the lowest concentration is obtained in the range of (16) microplastics / liter. Under the influence of freezing, the highest concentration of microplastics is obtained in the range of (648) microplasics / liter, while the lowest concentration Is obtained in the range of (20) microplastics / liter.
 Through the results, it is noted that there is a noticeable gradient in the concentration of microplastics for the samples that have been studied. It is also noted that there is an increase in the concentration of microplastics with repeated reuse during continuous periods of time. It is recommended that more studies and research be conducted indicating the extent of the impact of microplastics on human health in addition to other environmental components with emphasis on finding treatment means to get rid of microplastics.

The Association Between Microplastics and Microbiota in Placentas and Meconium: The First Evidence in Humans.

Pregnancy and infancy are vulnerable times for detrimental environmental exposures. However, the exposure situation of microplastics (MPs) for mother-infant pairs and the adverse health effect of MPs are largely unknown. Therefore, we explored MP exposure in placentas and meconium samples, and the potential correlation of MP exposure with microbiota in placentas and meconium. A total of 18 mother-infant pairs were effectively recruited from Shanghai, China. The study required pregnant women to provide placentas and meconium samples. An Agilent 8700 laser infrared imaging spectrometer (LDIR) was applied to identify MPs. Microbiota detection was identified by 16S rRNA sequencing. Sixteen types of MPs were found in all matrices, and polyamide (PA) and polyurethane (PU) were the major types we identified. MPs detected in samples with a size of 20-50 μm were more than 76.46%. At the phylum level, both placenta and meconium microbiota were mainly composed of Proteobacteria, Bacteroidota, and Firmicutes. We also found some significant differences between placenta and meconium microbiota in β-diversity and gut composition. Additionally, we found polystyrene was inversely related with the Chao index of meconium microbiota. Polyethylene was consistently inversely correlated with several genera of placenta microbiota. The total MPs, PA, and PU consistently impacted several genera of meconium microbiota. In conclusion, MPs are ubiquitous in placentas and meconium samples, indicating the wide exposure of pregnant women and infants. Moreover, our findings may support a link between high concentration of MPs and microbiota genera in placentas and meconium. Additionally, there were several significant associations between the particle size of MPs in 50-100 μm and meconium microbiota.

Spatial and seasonal distribution of microplastic in surface water of Bueng Boraphet Wetland-a Ramsar wetland in Thailand.

This study sought to assess microplastic contamination in the surface water of the inland freshwater wetland, Bueng Boraphet Wetland, Thailand, which is a lentic system with various land-use patterns, including community areas, agricultural areas, and natural resource conservation areas. In 2019, water samples were collected during the wet and dry periods from the three land-use zones at depths of 0-30cm using a plankton net with 333µm in mesh size. The water samples were digested via a wet peroxide oxidation process prior to the identification of microplastic morphology using a stereomicroscope. The polymer types of microplastic were analyzed using Fourier transform infrared spectrophotometry. Microplastic was found to range from 0.00 to 4.61 particles/m2 (0.34 ± 0.81 particles/m2) or 0.0 to 19.57 particles/m3 (1.44 ± 3.4 particles/m3). Furthermore, significantly high amounts of microplastics were found in samples from the community area. No microplastic was detected in the sample from the natural resource conservation area. The quantity of microplastic did not significantly differ between the sampling periods. Polymer types, including polyester, polypropylene, and polyethylene terephthalate, were identified in this study. The microplastics were predominantly small and were colored black or red. Microplastic with a fiber shape (93.8%) was observed. Besides the specific gravity of the microplastic and hydrological characteristics, the high concentration of microplastics found in samples from the community area (0.62 ± 0.79 particles/m2 or 2.63 ± 3.36 particles/m3) is likely related to the high human pressure. As microplastic contamination can impact aquatic animals and wetland ecosystems, appropriate control measures for human activities and plastic waste management are required.

Sources and distribution of microplastics in the east China sea under a three-dimensional numerical modelling

Microplastics are new pollutants found in various environments; moreover, high concentrations of microplastics have been proved to harm aquatic organisms. To understand the high abundance of microplastics in the East China Sea (ECS), where the Zhoushan fishing ground is located, this study investigated the transportation and spatial distribution of microplastics from the Changjiang River Estuary (CE) to the ECS via three-dimensional numerical modelling. Utilising observations of microplastics at the surface of the ECS and backward particle tracking, three sources of microplastics were identified: the Changjiang River, Hangzhou Bay, and coastal area of Nantong city. Moreover, Southern Korea contributed to the microplastics in ECS. After microplastics are released from these sources, monsoons, currents, the Changjiang plume, and tides cause significant seasonal differences in the hot spots for microplastics in the ECS; moreover, the generation of ocean fronts may promote microplastic accumulation. In addition, the settling characteristics of microplastics were shown to influence their distributions; for example, large amounts of microplastics accumulated at the bottom of the riverbeds. This study enables a more complete assessment of microplastic transport from estuaries to the open sea and provides a spatial and temporal distribution of microplastics at the surface of the ECS.

Unraveling microplastics removal in wastewater treatment plant: A comparative study of two wastewater treatment plants in Thailand

Wastewater treatment plants (WWTPs) are considered as a problematic pathway for microplastics (MPs) entering the oceans. This study compares the efficiency of MP removal in two different WWTPs (A1 and A2) with a conventional treatment system located in Bangkok, Thailand. WWTP-A2 is equipped with a pilot-scale ultrafiltration (UF) as a final polishing step. The number of MPs in the influent entering A1 and A2 was 16.55 ± 9.92 and 77.00 ± 7.21 MP/L, respectively. The average of 3.52 ± 1.43 and 10.67 ± 3.51 particles per L was found in the effluent discharged from A1 and A2, respectively, to nearby canals. The removal efficiency of WWTP-A2 built as a closed underground system was shown to be up to 86.14% which is more efficient than the conventional WWTP (A1). MPs were subsequently removed by a UF unit which resulted in a removal efficiency of 96.97%. However, when a large volume of treated wastewater volume is considered, a high concentration of MPs is discharged daily with the final effluent if the efficiency remains the same. The size fraction of 0.5–0.05 mm contributed to the largest proportion of MPs, and fibers were detected as the dominant group at both study sites. Results from a Fourier Transform Infrared Spectroscopy (FT-IR) confirmed that most fibers were polyethylene terephthalate (PET) derived from clothes. MPs retained in the sludge ranged from 2.63 × 104 to 4.74 × 104 particles per kilogram of dry sludge. A significant number of MPs can spread further to the environment by soil application. The results of the study indicate that the design of WWTPs and the addition of advanced tertiary treatment can improve MP removal efficiency of a WWTP. Moreover, the absence of a primary sedimentation tank in both treatment plants may influence the removal efficiency.

Assessment of microplastics in Irish river sediment

Microplastics (MPs) are environmental pollutants of growing concern, and awareness of MPs pollution in marine and freshwater environments has increased in recent years. However, knowledge of MPs contamination in riverine sediments in Ireland is limited. To address this, we collected and analysed sediment samples from 16 selected sites along the River Barrow. Microplastics were extracted through a density separation method, after which their size, colour, and shape were analysed under a stereo microscope (Optica SZM-2). Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy was used to identify polymer types. A total of 690 MPs were recovered from the 16 sites, with fibres as the dominant MP type. The highest concentration of MPs was 155 MP fibres kg−1 wet sediment found in samples collected from Graiguenamanagh, Co. Kilkenny (GK). The majority of the recovered MPs were polyethylene (PE), polypropylene (PP), nylon, and cellulose acetate (CA) fibres. Overall, this study highlighted the presence of MPs in Irish river sediments and provided a baseline for future studies on MPs pollution. Further research is needed to better understand sources, distribution, and effects of MPs in freshwater ecosystems.

Microplastics and Heavy Metals Removal from Fresh Water and Wastewater Systems Using a Membrane

Water pollution, resulting from the degradation of plastics into microplastics, exposes humans and other living organisms to contaminated drinking water. Microplastics are capable of adsorbing toxic heavy metals which are carcinogenic and may affect the reproductive functions of living organisms. Hence, this study focuses on the characterization and quantification of microplastics in water to raise the awareness and propose a method of dealing with this emerging pollutant in various aqueous environments. The microplastics were separated from water using polyvinylidene difluoride (PVDF) and PVDF modified with carbon nano-onions (CNOs). The PVDF exhibited the highest concentration of microplastics in the wastewater influent (140 ± 1.85 MP/L) compared to the effluent (8.8 ± 2.10 MP/L), tap water (6.5 ± 5.77 MP/L), and lake water (10 ± 2.65 MP/L). The stereo microscope displayed red, blue, and black colored plastics. The morphological properties were determined using SEM. ATR-FTIR, equipped with Spectrum 10 Spectroscopy Software was used to establish the presence of high-density polyethylene (50%), poly(1,4-butylene terephthalate) (16.6%), nylon 12 (16.6%), and cellulose (16.6%) in the influent. The quantification of heavy metals extracted from the microplastics indicated that the concentrations of As (1.759 to 8.699 mg/L), Cu (83.176 mg/L) and Zn (0.610 mg/L) were above the acceptable limits. Our work is beneficial for the development of a microplastics monitoring protocol for various municipalities. Water treatment plants may also include the treatment of microplastics in the influent and monitor the effluent before the water is released back into the environment.

Local Monitoring Should Inform Local Solutions: Morphological Assemblages of Microplastics Are Similar within a Pathway, But Relative Total Concentrations Vary Regionally

Pathways for microplastics to aquatic ecosystems include agricultural runoff, urban runoff, and treated or untreated wastewater. To better understand the importance of each pathway as a vector for microplastics into waterbodies and for mitigation, we sampled agricultural runoff, urban stormwater runoff, treated wastewater effluent, and the waterbodies downstream in four regions across North America: the Sacramento Delta, the Mississippi River, Lake Ontario, and Chesapeake Bay. The highest concentrations of microplastics in each pathway varied by region: agricultural runoff in the Sacramento Delta and Mississippi River, urban stormwater runoff in Lake Ontario, and treated wastewater effluent in Chesapeake Bay. Material types were diverse and not unique across pathways. However, a PERMANOVA found significant differences in morphological assemblages among pathways (p < 0.005), suggesting fibers as a signature of agricultural runoff and treated wastewater effluent and rubbery fragments as a signature of stormwater. Moreover, the relationship between watershed characteristics and particle concentrations varied across watersheds (e.g., with agricultural parameters only being important in the Sacramento Delta). Overall, our results suggest that local monitoring is essential to inform effective mitigation strategies and that assessing the assemblages of morphologies should be prioritized in monitoring programs to identify important pathways of contamination.

The changes of microplastics’ behavior in adsorption and anaerobic digestion of waste activated sludge induced by hydrothermal pretreatment

Waste activated sludge (WAS) contains high concentrations of microplastics (MPs), which could serve as vectors of various organic pollutants and heavy metals, causing synergistic transportation and pollution. The application of combined hydrothermal pretreatment (HTP) and anaerobic digestion (AD) has raised growing concerns since the low-temperature hydrothermal treatment could enhance the biogas production of WAS. However, the changes in physicochemical properties, adsorption performances, and effects on AD of MPs by HTP have not been studied. The study used three typical MPs in WAS, and it was found that the HTP (170°C & 30min) increased MPs’ specific surface area and carbonyl index (CI) while decreasing the relative crystallinity. The adsorption capacity to Cd increased through the carbonylation for polyethylene microplastic (PE-MP) and polystyrene microplastic (PS-MP) while decreasing by the dechlorination for polyvinyl chloride microplastic (PVC-MP). Meanwhile, increased hydrophilicity reduced the adsorption capacities of all three typical MPs for ofloxacin. The above results indicated that the HTP could be worth blocking the adsorption of polar MPs for polar pollutants. For the pristine MPs, only PVC-MP at the highest concentration (0.5 g kg−1 VS) significantly (p < 0.05) reduced methane production by 16.2 ± 3.3% of WAS without the HTP. However, the HTP resulted in significant (p < 0.05) inhibition of methane production of WAS at high concentrations of PE-MP and PVC-MP (e.g., 0.1 and 0.5 g kg−1 VS), which was due to the acceleration of the released toxic plastic additives (dibutyl phthalate, dimethyl phthalate, and bisphenol-A). Microbial analysis showed the abundances of vital anaerobes, such as acid-producing bacteria (Acetoanerrobium and Mesotoga), proteolytic bacteria (Proteiniborus), and methanogens (Methanosaeta) clearly decreased with the PE-MP and PVC-MP after the HTP, which might result in the decreased methane production. The study provided deep-insight of MPs’ behaviors during the combined HTP-AD process.

Cyclic AMP and biofilms reveal the synergistic proliferation strategy of Pseudomonas aeruginosa and Escherichia coli under the costimulation of high concentrations of microplastics and enrofloxacin

Microplastics (MPs) provide attachment sites for biofilm formation of microorganisms, which can promote their resistance to environmental stress has been proved. However, the effect of MPs on synergy survival among microorganisms under antibiotic stress remains unclear. In the present study, the proliferation of Escherichia coli and Pseudomonas aeruginosa was assessed under enrofloxacin stress with the influence of MPs. Here, MPs reduced the growth speed of E. coli and enhanced that of P. aeruginosa, especially at 12 h, but the final value of OD600 and CFU of both bacteria not be influenced. E. coli was enrofloxacin sensitive (MIC = 0.25 μg/mL), and a high MP concentration in the presence of enrofloxacin notably enhanced the biofilm formation ability of P. aeruginosa, but proliferation decreased. In the coculture system, the proliferation of E. coli (increased 1.42-fold) and P. aeruginosa (increased 1.06-fold) both increased under enrofloxacin stress (0.25 μg/mL) with high-concentration MP addition. P. aeruginosa may provide the biofilm matrix for E. coli to resist the stress of enrofloxacin. The high concentration of cyclic AMP secreted by E. coli may slightly inhibited biofilm formation, leading to a decrease in the fitness cost of P. aeruginosa; thus, the proliferation of P. aeruginosa increased. The present study is the first to show that MP combined with antibiotics stimulates the metabolic cooperation of bacteria to promote proliferation.

Antagonistic and synergistic effects of warming and microplastics on microalgae: Case study of the red tide species Prorocentrum donghaiense

Bibliometric network analysis has revealed that the widespread distribution of microplastics (MPs) has detrimental effects on marine organisms; however, the combined effects of MPs and climate change (e.g., warming) is not well understood. In this study, Prorocentrum donghaiense, a typical red tide species in the East China Sea, was exposed to different MP concentrations (0, 1, 5, and 10 mg L−1) and temperatures (16, 22, and 28 °C) for 7 days to investigate the combined effects of MPs and simulated ocean warming by measuring different physiological parameters, such as cell growth, pigment contents (chlorophyll a and carotenoid), relative electron transfer rate (rETR), reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA), and adenosine triphosphate (ATP). The results demonstrated that MPs significantly decreased cell growth, pigment contents, and rETRmax, but increased the MDA, ROS, and SOD levels for all MP treatments at low temperature (16 °C). However, high temperatures (22 and 28 °C) increased the pigment contents and rETRmax, but decreased the SOD and MDA levels. Positive and negative effects of high temperatures (22 or 28 °C) were observed at low (1 and 5 mg L−1) and high MP (10 mg L−1) concentrations, respectively, indicating the antagonistic and synergistic effects of combined warming and MP pollution. These results imply that the effects of MPs on microalgae will likely not be substantial in future warming scenarios if MP concentrations are controlled at a certain level. These findings expand the current knowledge of microalgae in response to increasing MP pollution in future warming scenarios.

International Legal Protection of the Marine Environment from Plastic Pollution

The subject of the work is the norms of international law regulating the protection of the marine environment from plastic pollution. The purpose of the work is to analyze the existing international legal regulation in the field of protection of the oceans from plastic pollution and to develop recommendations aimed at improving the level of protection of the marine environment. In the process of preparing the work, various methods, means of cognition and logical techniques were used, such as analysis, synthesis, deduction, induction, etc. Currently, plastic pollution is one of the main threats to the oceans, every year a huge amount of plastic debris from various sources located both directly in the marine environment and on land enters the marine environment. Plastic pollution is detected even in the most remote corners of the planet, while the level of pollution in them is comparable to industrially developed areas. High concentrations of microplastics are found even in the Arctic sea ice, while it is at least two orders of magnitude higher than in the heavily polluted surface waters of the Pacific Ocean. These facts speak both about the urgent need to develop legal protection of the marine environment from pollution, and about the high degree of relevance of the research topic, its practical and scientific significance. The conducted research allowed us to come to a number of conclusions and proposals of a practical and theoretical nature. Among them is a proposal on the need to include in Annex 1 to the International Convention on the Control of Harmful Antifouling Systems on Ships those antifouling systems that are a source of microplastics entering the marine environment. Among other things, based on the data on plastic pollution of the world's oceans, it is concluded that the current system of legal protection of the marine environment from pollution does not cope with this problem.

Polyethylene microplastics and substrate availability can affect emergence responses of the freshwater insect Chironomus sancticaroli.

Pollution caused by polyethylene microplastics (MP) has been reported for aquatic environments worldwide. However, despite recurrent research for several aquatic organisms, the effects of MP on the emergence stage of freshwater insects from tropical environments are little known. This study is the first to assess the emergence of the Brazilian native species Chironomus sancticaroli Strixino & Strixino, 1981 when exposed to primary polyethylene microplastics (size 40-48 µm). We performed two exposure scenarios, with a substrate (standard assays) and without substrate (as a stressful experience), and recorded emergence responses. The MP did not affect the species' emergence rate, but these rates were statistically different for the standard and stressful exposure scenarios. In bioassays without substrate, the high concentrations of MP caused anticipation of the insect's emergence (5-6 days). On the other hand, female emergence time was longer than males in standard bioassays. The substrate absence caused a slight increase in the left female wing's length and the potential female fecundity. These findings suggest that the polyethylene microplastics and substrate availability can affect the emergence dynamics of the tropical insect C. sancticaroli.