Pollution Of Marine Environment Research Articles

Per- and polyfluoroalkyl pollution in marine environments: a viewpoint about Africa

Per- and poly-fluoroalkyl substances (PFAS) represent an extensive and expanding group of chemicals considered contaminants of emerging concern (CECs). These elements have found widespread usage in diverse industrial and commercial sectors since the 1940s. The advancement of modern analytical methods in developed countries has significantly contributed to the increased research on the environmental behavior and risk assessment of PFAS. However, what about developing countries? Over time, the focus on PFAS has expanded beyond legacy PFAS to encompass novel ones. In this perspective, we focus on analyzing the existing knowledge concerning PFAS in the marine environment, aiming to shed light on the limited research pertaining to per- and polyfluoroalkyl pollution in the marine ecosystems of Africa.

Unveiling high concentrations of small microplastics (11–500 μm) in surface water samples from the southern Weddell Sea off Antarctica

Recent studies have highlighted the prevalence of microplastic (MP) pollution in the global marine environment and these pollutants have been found to contaminate even remote regions, including the Southern Ocean south of the polar front. Previous studies in this region have mostly focused on MPs larger than 300 μm, potentially underestimating the extent of MP pollution. This study is the first to investigate MPs in marine surface waters south of the polar front, with a focus on small MPs 500–11 μm in size. Seventeen surface water samples were collected in the southern Weddell Sea using an in-house-designed sampling system. The analysis of the entire sample using micro-Fourier transform infrared spectroscopy (μFTIR) with focal plane array (FPA) detection revealed the presence of MPs in all samples, with the vast majority of the MPs detected being smaller than 300 μm (98.3 %). The mean concentration reached 43.5 (± 83.8) MPs m−3, with a wide range from 0.5 to 267.2 MPs m−3. The samples with the highest concentrations differed from the other samples in that they were collected north of the continental slope and the Antarctic Slope Current. Sea ice conditions possibly also influenced these varying concentrations. This study reports high concentrations of MPs compared to other studies in the region. It emphasizes the need to analyze small MPs, down to a size of 11 μm or even smaller, in the Antarctic Treaty Area to gain a more comprehensive understanding of MP pollution and its potential ecological impacts.

Evaluation of the Environmental Impact of Oil Pollution from Maritime Transportation

Maritime transportation, which has a growing share in global transportation, and especially ships with large carrying capacities, increases the risk of marine environment pollution. The fact that maritime transport takes place not only in the open seas, but also in coastal waters, narrow waters with high navigational risk, and sea areas in the vicinity of ecologically sensitive zones necessitates prediction and calculation of this risk, as well as taking precautionary measures. This study seeks to identify optimal intervention strategies and determine where and when interventions should take place to minimize the adverse effects of potential oil pollution on the marine environment, utilizing a simulation model based on the example of Istanbul's Tuzla shipyard region. The Potential Incident Simulation and Evaluation System (PISCES) decision support system, which predicts the spread of pollution based on the behavior of oil in water, was used in the simulation. As oil weathering processes, which result in evaporation, emulsification, and dispersion, vary depending on the type of oil, weather, and oceanographic conditions, their seasonal average values were obtained from the relevant institutions and entered into the simulation. In the dispersion of oil, the surface current structure, which plays the most pivotal role, has been established by PISCES, based on the reference vector obtained from the relevant institute.Given that, once the oil disperses, starts to submerge and sedimentation occurs, intervention becomes impossible, leading to long-lasting negative impacts on the marine ecosystem, timely response to marine pollution caused by ships is of utmost importance. Intervention strategies should be selected based on dispersion time and quantity, as well as the duration of the interaction of oil with the coast. Another consequence is that oil pollution can affect not only the marine environment but other areas as well, such as adjacent environmentally sensitive areas, causing devastation to the marine habitat.

Preliminary Study on Microplastic Contamination in Black Sea Cetaceans: Gastrointestinal Analysis of Phocoena phocoena relicta and Tursiops truncatus ponticus.

Plastic pollution is a global concern that has a significant impact on marine life. Plastic is widely used and has become a pervasive pollutant in marine environments. Plastic contamination has been documented both in marine environments and biota. Plastic contamination in cetacean gastro-intestinal tract (GIT) content has received limited attention, especially in the Black Sea. This study aims to investigate plastic contamination in the GITs of bottlenose dolphins and harbour porpoises, introducing a novel methodology. Given the limited exploration of this issue in the Black Sea, the research predominantly focuses on microplastic contamination. The GITs were sampled through necropsy from stranded and by-caught cetaceans, and content was washed through a multi-sieves tool. The material retained on each sieve was analysed following specific protocols. All (100%) of the GITs contained plastics (meso- and microplastics). In total, 1059 items (fibres, fragments, and beads) ranging from 22.86 µm to 5776 µm were found, suggesting a high contamination level in the Black Sea cetaceans. Future efforts should concentrate on increasing the number of samples and using the results for the implementation of the Marine Strategy Framework Directive (MSFD).

Assessing the impact of banning the single-use plastic carrier bags: a case study for Kenyan marine environment looking at macro, meso, and microplastics.

Poor waste management and unsustainable institutional and individual behaviors, have led to the accumulation of plastic litter in many habitats worldwide. Assessment of plastic pollution in Kenyan marine environment was conducted focusing on the impact of banning the single-use plastic carrier bags in Kenya. The quantification, composition, and distribution of plastics were determined at nine (9) beaches along Kenyan coastline using standing stock method. A total of 750 plastic items were collected and categorized with only 47 pieces being single-use plastic carrier bags. A great number of plastics (n = 383), were identified by their original use, with packaging plastics being the most common (n = 155). Macroplastics were the overall dominant plastics at 76%, mesoplastics, 21% and microplastics, 3%, which were altogether dominated by low-density polyethylene (LDPE) at (46%), followed by polypropylene (PP), 30%; polyethylene tetraphthalate (PET), 9%; polyvinyl chloride (PVC), 8%; and polystyrene (PS), 7%. The absence of identifiable single-use plastic carrier bags in 6 out of 9 beaches signified the effectiveness of the ban in Kenya. Monitoring of trends and sources of plastic debris is encouraged to help enhance the science-policy linkage aimed at reducing marine plastic pollution.

Discharge of potentially toxic elements from acid sulfate soils in western Finland: Conflict between water protection and land use?

Acid sulfate soils (ASS) are commonly found in many coastal areas worldwide and typically develop from artificial draining of sulfidic sediments, which release acidity and metals, causing unfavuorable effects on recipient watercourses. This study estimates the actual amounts of metals and elements carried to the Gulf of Bothnia and the Baltic Sea by stream water yearly. The combined load from the many small streams and ditches was found to be proportionally high related to the size of their catchment, emphasizing the importance of including numerous small streams in the understanding of pollution in fresh water and marine environments. This study shows that Cd concentrations in the majority of the studied rivers exceed the Environmental Quality Standard set by the European Union (EU). This causes lowered ecological and chemical status according to the European classification system. Many potentially toxic elements discharge yearly to the Baltic Sea in large quantities from the study area: Thousands of tons of Al and Mn, tens of tons of Co, Cu and Ni, and hundreds of kg of Cd. A challenge for the estimation was irregular, or even missing, data for many rivers, which highlights careful planning of monitoring programs. While the current land use on ASS requires efficient drainage, the national and European strategies and legislation aim towards improved status in water bodies and forbid pollution of the environment. Therefore, the land use and water protection policy conflict.

The unique salt bridge network in GlacPETase: a key to its stability.

The extensive accumulation of polyethylene terephthalate (PET) has become a critical environmental issue. PET hydrolases can break down PET into its building blocks. Recently, we identified a glacial PET hydrolase GlacPETase sharing less than 31% amino acid identity with any known PET hydrolases. In this study, the crystal structure of GlacPETase was determined at 1.8 Å resolution, revealing unique structural features including a distinctive N-terminal disulfide bond and a specific salt bridge network. Site-directed mutagenesis demonstrated that the disruption of the N-terminal disulfide bond did not reduce GlacPETase's thermostability or its catalytic activity on PET. However, mutations in the salt bridges resulted in changes in melting temperature ranging from -8°C to +2°C and the activity on PET ranging from 17.5% to 145.5% compared to the wild type. Molecular dynamics simulations revealed that these salt bridges stabilized the GlacPETase's structure by maintaining their surrounding structure. Phylogenetic analysis indicated that GlacPETase represented a distinct branch within PET hydrolases-like proteins, with the salt bridges and disulfide bonds in this branch being relatively conserved. This research contributed to the improvement of our comprehension of the structural mechanisms that dictate the thermostability of PET hydrolases, highlighting the diverse characteristics and adaptability observed within PET hydrolases.IMPORTANCEThe pervasive problem of polyethylene terephthalate (PET) pollution in various terrestrial and marine environments is widely acknowledged and continues to escalate. PET hydrolases, such as GlacPETase in this study, offered a solution for breaking down PET. Its unique origin and less than 31% identity with any known PET hydrolases have driven us to resolve its structure. Here, we report the correlation between its unique structure and biochemical properties, focusing on an N-terminal disulfide bond and specific salt bridges. Through site-directed mutagenesis experiments and molecular dynamics simulations, the roles of the N-terminal disulfide bond and salt bridges were elucidated in GlacPETase. This research enhanced our understanding of the role of salt bridges in the thermostability of PET hydrolases, providing a valuable reference for the future engineering of PET hydrolases.

Differential capacity of phragmites ecotypes in remediation of inorganic contaminants in coastal ecosystems: Implications for climate change

Remediating inorganic pollutants is an important part of protecting coastal ecosystems, which are especially at risk from the effects of climate change. Different Phragmites karka (Retz) Trin. ex Steud ecotypes were gathered from a variety of environments, and their abilities to remove inorganic contaminants from coastal wetlands were assessed. The goal is to learn how these ecotypes process innovation might help reduce the negative impacts of climate change on coastal environments. The Phragmites karka ecotype E1, found in a coastal environment in Ichkera that was impacted by residential wastewater, has higher biomass production and photosynthetic pigment content than the Phragmites karka ecotypes E2 (Kalsh) and E3 (Gatwala). Osmoprotectant accumulation was similar across ecotypes, suggesting that all were able to successfully adapt to polluted marine environments. The levels of both total soluble sugars and proteins were highest in E2. The amount of glycine betaine (GB) rose across the board, with the highest levels being found in the E3 ecotype. The study also demonstrated that differing coastal habitats significantly influenced the antioxidant activity of all ecotypes, with E1 displaying the lowest superoxide dismutase (SOD) activity, while E2 exhibited the lowest peroxidase (POD) and catalase (CAT) activities. Significant morphological changes were evident in E3, such as an expansion of the phloem, vascular bundle, and metaxylem cell areas. When compared to the E3 ecotype, the E1 and E2 ecotypes showed striking improvements across the board in leaf anatomy. Mechanistic links between architectural and physio-biochemical alterations are crucial to the ecological survival of different ecotypes of Phragmites karka in coastal environments affected by climate change. Their robustness and capacity to reduce pollution can help coastal ecosystems endure in the face of persistent climate change.

Advanced strategies for marine antifouling based on nanomaterial-enhanced functional PDMS coatings

Marine biofouling seriously affects human marine exploitation and transportation activities, to which marine antifouling (AF) coatings are considered to be the most cost-effective solution. Since the mid-20th century, human beings have dedicated their efforts on developing AF coatings with long cycle and high performance, leading to a large number of non-target organisms' distortion, death and marine environmental pollution. Polydimethylsiloxane (PDMS), is considered as one of the representative environment-friendly AF materials thanks to its non-toxic, hydrophobic, low surface energy and AF properties. However, PDMS AF coatings are prone to mechanical damage, weak adhesion strength to substrate, and poor static AF effect, which seriously restrict their use in the ocean. The rapid development of various nanomaterials provides an opportunity to enhance and improve the mechanical properties and antifouling properties of PDMS coating by embedding nanomaterials. Based on our research background and the problems faced in our laboratory, this article presents an overview of the current progress in the fields of PDMS composite coatings enhanced by different nanomaterials, with the discussion focused on the advantages and main bottlenecks currently encountered in this field. Finally, we propose an outlook, hoping to provide fundamental guidance for the development of marine AF field.

Marine pollution management in response to plastic waste under international law and national law – challenges and implications for developing countries: a case study of Vietnam

One of the most widespread environmental problems confronting the global community is marine pollution, particularly the adverse impact of plastic debris. This issue not only has detrimental effects on ecosystems, environmental quality, human health, and habitats of people and species worldwide, but also represents a formidable barrier to the protection of the marine environment and the pursuit of sustainable ocean development. Vietnam, as a Southeast Asian country with a long coastline, faces the issue of significant plastic debris in its waters. Despite significant efforts being made by the Vietnamese Government in developing a legislative framework as a comprehensive approach to ‘white pollution’ in accordance with international environmental standards and its international and regional undertakings on environmentalism, challenges persist in the establishment of effective management of marine environmental pollution. As a developing country grappling with certain challenges in resource allocation for socio-economic development, Vietnam, like other developing countries in the region, face substantial difficulties and hurdles in managing marine plastic pollution. This article first presents the current situation in respect of plastic pollution, with a focus on marine plastic pollution stemming from land-based plastic waste, in Vietnam. The article then concentrates on the regulatory response at both international and national levels to determine whether the international and national instruments comprehensively address the plastic waste issue. The article also explores and critiques the weaknesses and difficulties in effectively managing and controlling the current harm and threat of plastic pollution. Thereafter, the article proposes some recommendations and solutions for the Vietnamese Government to move toward more effective plastic pollution management.

The influence of emerging atmospheric organophosphorus flame retardants from land source emissions on the East China Sea

Organophosphate flame retardants (OPFRs) pose a new challenge to the marine environment due to their toxicity and persistence. This study explores the contributions of OPFR emissions from different land sources and sectors to its contamination of the East China Sea (ECS) using a novel atmospheric transport model（ChnMETOP）for POPs and a marine food web model. The results show that the major land sources causing OPFR pollution in the ECS were situated in Yangtze River Delta (YRD) and middle reach areas of China's Yangtze River, confirming that source proximity made most significant contributions to OPFR pollution in the ECS. Among those OPFR emission sectors, industrial emissions accounted for the highest modeled OPFR levels in the seawaters, followed by the OPFR usage process in textile, plastic, and rubber products. Assessment of bioaccumulation of OPFR in the marine food web of the ECS and the potential risk in commercial fish consumers reveals lower exposure risk via dietary fish ingestion. However, the risk might increase if OPFRs are continuously bioaccumulated in the biotic and released into the abiotic marine environment. This study simultaneously identified both the source locations and emission sectors, thereby providing important policy implications in mitigating OPFR pollution in the ECS marine environment.

ASEAN’s soft law on marine environmental pollution

The sea-bound development of humankind is the most pronounced and significant feature of the 21st century, which is expected to be the ocean’s century. The United Nations’ Sustainable Development Goals (SDGs) recognise the conservation and sustainable use of seas and oceans as an indicator of a country’s development level. Humankind faces grave challenges associated with marine environmental pollution due to the accelerated pace of maritime resource extraction. Owing to the uniformity and the transboundary nature of the marine environment, preventing and reducing marine environmental pollution is not only a national concern but also a regional and global priority. As a region with diverse ecosystems and abundant marine resources, The Association of Southeast Asian Nations (ASEAN) has long viewed marine environmental preservation as a cornerstone of its environmental protection strategy. This paper posits the effectiveness of ASEAN’s “soft law” and discusses member states’ cooperation through the establishment of regional documents and mechanisms to address environmental pollution. On that foundation, the study underscores the role of ASEAN’s “soft law” and projects its trajectory concerning the regional legal framework for protecting the marine environment.

Aquatic aerobic biodegradation of commonly flushed materials in aerobic wastewater treatment plant solids

Microfibers and microplastics originating from wastewater treatment plant (WWTP) effluents are significant pollutants in freshwater sources and marine environments. This research investigated the biodegradation of cotton microfibers generated from bleached cotton jersey knit fabric and commercially available flushable wipes, polypropylene-based (PP) nonwoven wipes containing a cellulose component, and tissue paper. Biodegradation was tested in wastewater treatment plants (WWTP) solids, seawater, and lakewater according to the ISO 14852 and ASTM D6691 standard methods in an ECHO respirometer. Degradation experiments continued until a plateau in CO2 emissions was reached, and the final biodegradation extent was calculated relative to the theoretical CO2 produced based on elemental analysis. The results showed that the cotton and other cellulosic materials/components biodegrade to a great extent, as expected for all conditions, whereas the PP did not degrade. In general, for the cellulose polypropylene composite wipes, the cellulose biodegraded readily; the presence of the PP did not hinder the cellulose biodegradation.

The immunotoxicity mechanism of hemocytes in Chlamys farreri incubated with noradrenaline and benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide alone or in combination

Benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE) is the active intermediate metabolite of benzo[a]pyrene (B[a]P) and is considered the ultimate immunotoxicant. The neuroendocrine immunoregulatory network of bivalves is affected under pollutant stress. Besides, bivalves are frequently affected by pollutants in marine environments, yet the combined effects of neuroendocrine factors and detoxification metabolites on bivalves under pollutant stress and the signal pathways that mediate this immunoregulation are not well understood. Therefore, we incubated the hemocytes of Chlamys farreri with the neuroendocrine factor noradrenaline (NA) and the B[a]P detoxification metabolite BPDE, alone or in combination, to examine the immunotoxic effects of NA and BPDE on the hemocytes in C. farreri. Furthermore, the effects of NA and BPDE on the hemocyte signal transduction pathway were investigated by assessing potential downstream targets. The results revealed that NA and BPDE, alone or in combination, resulted in a significant decrease in phagocytic activity, bacteriolytic activity and the total hemocyte count. In addition, the immunotoxicity induced by BPDE was further exacerbated by co-treatment with NA, and the two showed synergistic effects. Analysis of signaling pathway factors showed that NA activated G proteins by binding to α-AR, which transmitted information to the Ca2+-NF-κB signaling pathway to regulate the expression of phagocytosis-associated proteins and regulated cytokinesis through the cAMP signaling pathway. BPDE could activate PTK and affect phagocytosis and cytotoxicity proteins through Ca2+-NF-κB signal pathway, also affect the regulation of phagocytosis and cytotoxicity by inhibiting the AC-cAMP-PKA pathway to down-regulate the expression of NF-κB and CREB. In addition, BPDE and NA may affect the immunity of hemocytes by down-regulating phagocytosis-related proteins through inhibition of the lectin pathway, while regulating the expression of cytotoxicity-related proteins through the C-type lectin. In summary, immune parameters were suppressed through Ca2+ and cAMP dependent pathways exposed to BPDE and the immunosuppressive effects were enhanced by the neuroendocrine factor NA.

Tort Liability for Trans-boundary Marine Environmental Pollution: Japans Radioactive Wastewater Discharge into the Sea as an Entry Point

Currently, the problem of trans-boundary marine environmental pollution is becoming increasingly prominent and Japans insistence on discharging nuclear wastewater despite protests from other countries has raised concerns among the population. Researchers have found that international conventions and other sources of international environmental law are lack of a liability system for trans-boundary environmental pollution. Therefore, this paper looks for gaps by applying the normative analysis method to retrieve the relevant liability system at the institutional level in order to compare and analyze it, and secondly, using the case analysis method to think about how to improve the liability system through case law practical perspective. The study concludes that it can be constructed from two perspectives, namely the responsibility of the State and the tort responsibility of private subject to adopt the system of tortious responsibility and both serve in parallel with that caused by environmental pollution compensate for damage. Due to the irreversibility of environmental pollution, initiating legal proceedings for redress after the event is often not the ultimate goal. Therefore, the ex-ante blocking mechanism need to be further improved and domestic law needs to be constantly improved to compensate for the shortcomings of international law. That help our country deal with the marine environmental pollution to provide methods and ideas.

Fifty-year study of microplastics ingested by brachyuran and fish larvae in the central English North Sea

Microplastics (MPs) are ubiquitous pollutants in marine environments. Among the many detrimental consequences of microplastic pollution, its consumption by marine biota is of particular relevance for human health, due to exposure through the food web. Long-term time-series biotic samples are overlooked sources of information for microplastics research. These collections are extremely valuable for the detection and monitoring of changes in marine environments. However, there are very few long-term studies (>10 years) of the uptake of microplastics by biota. Here, we used Dove Time Series planktonic samples (from 1971 to 2020) to assess the presence and prevalence of microplastics in the English North Sea coast over time. Fish and brachyuran larvae were selected due to their commercial importance and consequent implications for human health. A custom enzymatic digestion method was used to extract microplastics for FTIR-ATR polymer identification. An increasing cumulative trend in MP ingestion was identified. Cellophane and polyethylene terephthalate were the polymer types found most frequently in both taxa. Although a total higher microplastics uptake was observed in fish, consumption was not significantly different between taxa over time. Equally, results were not clearly related to microplastics shape or polymer type. This work did not find significant long-term evidence on the increasing uptake of microplastic particles by zooplankton over time. However, the results of this report identified additives, plasticisers, and other more complex and hazardous compounds that should not be released to the environment (e.g., bis-(2-hydroxyethyl) dimerate, propylene glycol ricinoleate) inside marine biota. The study detailed herein provides a case study for the use of long-term time-series in providing accurate assessments of microplastic pollution in marine biota.

Impact of nanoplastics on membrane scaling and fouling in reverse osmosis desalination process

Nanoplastics (NPs) are a prevalent type of emerging pollutant in marine environment. However, their fouling behavior and impact on reverse osmosis (RO) membrane performance remain unexplored. We investigated the relationship between polystyrene (PS), one of the most abundant NPs, with silica scaling and humic acid (HA) fouling in RO. The results demonstrated that the surface potential of NPs played an important role in the combined scaling and fouling process. Compared with the negatively charged NPs (original PS and carboxyl group modified PS, PS−COOH), the amino-functionalized PS (PS−NH2) with positive surface charge significantly accelerated membrane scaling/fouling and induced a synergistic water flux decline, due to the strong electrostatic attraction between PS−NH2, foulants, and the membrane surface. The amino groups acted as binding sites, which promoted the heterogeneous nucleation of silica and adsorption of HA, then formed stable composite pollutants. Thermodynamic analysis via isothermal titration calorimetry (ITC) further confirmed the spontaneous formation of stable complexes between PS−NH2 and silicates/HA. Our study provides new insights into the combined NPs fouling with other scalants or foulants, and offers guidance for the accurate prediction of RO performance in the presence of NPs.

Prevention and control of ship-source pollution in the Arctic shipping routes: challenges and countermeasures.

Ship-source pollution is one of the important contributors to marine environment pollution. Because the legal status of the Arctic shipping routes is not clear, there is a considerable degree of dispute in the application of the rules on the prevention and control of ship-source pollution. The increased melting of sea ice undermines the legal legitimacy of the "ice-covered areas" clause under the United Nations Convention on the Law of the Sea. The conflict between the application of the Polar Code and "ice-covered areas" will also reach an initial conclusion in the context of melting sea ice. However, the inadequacy of ship-source pollution rules in the Polar Code hampers its application, which has led to a negative impact on the more active role in the governance of pollution from Arctic shipping. For replying to the Challenges in the prevention of ship-source pollution in Arctic shipping routes, the relevant rules of the Polar Code need to be further improved, while a more binding HFO ban according to ship types needs to be applied. Therefore, a more important role in the future Arctic governance mechanism will be played by the enhanced enforcement of the Polar Code, meanwhile, the target for uniform international regulation of preventing and controlling ship-source pollution in Arctic shipping routes should be achieved.

The seasonality of the concentration of endocrine phenolic compounds in the matter attached to the surface of microplastics

Rapid biofilm formation on microplastic (MP) surfaces in marine environments and the tendency of hydrophobic pollutants to bioaccumulate may increase the exposure of organisms to ingested plastics and transport pollutants far from their sources. The role of the matter attached to MPs (MaM) in the interactions between MPs and other pollutants in marine environments is poorly understood. This paper studies pollutant sorption in MaM for three phenolic endocrine-disrupting chemicals (EDCs): bisphenol A (BPA), 4-tert-octylphenol (4-t-OP), and 4-nonylphenol (4-NP). Polypropylene (PP), expanded polystyrene (EPS), and polylactide (PLA) MPs were exposed to an environment conducive to biofouling (Vistula Lagoon, Baltic Sea) for four weeks in summer, spring, and winter. The concentrations of EDCs in MaM and the suspended particulate matter (SPM) were similar and were 2–3 orders of magnitude higher than those in water and sediment. The type and morphology of the polymers were less significant for determining the concentrations of EDCs in MaM than the season. The concentrations were higher in the growing season than in winter. EDCs increased linearly with the increase in particulate organic carbon. The relationships between organic carbon partition coefficients and octanol/water partition coefficients indicate that hydrophobic partitioning into organic matter was the dominant mechanism of 4-t-OP and 4-NP binding in MaM and in SPM. For BPA, additional sorption mechanisms seem to be significant. In addition to the direct sorption from ambient water, the binding of phytoplankton-derived particles, most probably via attachment to extracellular polymeric substances, appears to be a source of EDCs in MPs. Rough estimates showed that the largest load of particulate matter and EDCs was attached to expanded polystyrene. This study suggests that the potential negative impacts of MPs on the environment are seasonal and that low-density porous plastics can be particularly effective carriers of large EDC loads.

Polystyrene nanoplastics mediate ROS production and apoptosis in A549 cell line

Abstract Background The ubiquity of single-use plastics has led to a global plastic pollution challenge with significant environmental and health consequences. Physical, chemical, and biological processes such as erosion, photo-oxidation, and biodegradation cause the plastic to erode, eventually forming debris in the size range from micro-plastics (MP) to nano-plastics (NP). Although NP has been extensively studied as a pollutant in marine and water environments, its potential detrimental effects, when present in the atmosphere, are still poorly investigated. In this study, we used polystyrene NP (PS-NP) in evaluating their potential toxic effects on the A549 cell line as a representative in vitro model of human lung epithelial cells. Methods The A549 cells were treated with concentrations of PS-NP (800 nm diameter) in the range of 10-500 mg/ml and for different time intervals up to 96 h. Cell viability, oxidative stress and senescence, were evaluated by commercially available kits, apoptosis was assessed by cytofluorimetric assay. Their capability to cross physiological barriers was assessed by Parallel Artificial Membrane Permeability Assay (PAMPA) and Caco-2 cell monolayer. Results PS-NP reduced cell vitality after 72 h of treatment at all the concentrations used. They also induced a marked increase in reactive oxygen species (ROS) production in a dose-dependent manner. Accordingly, PS-NP upregulated ROS-related genes evaluated by qPCR. PS-NP induced apoptosis after 96 h of treatment, whereas they were unable to induce senescence at the size and concentrations used. As expected, PAMPA results revealed no passive diffusion of PS-NP after 3 and 18 h, caco-2 assay excluded additional permeation mechanisms within 24h. Conclusions This study showed that atmospheric PS-NPs can represent a hazard to human lung health once inhaled. They cannot be degraded; thus they can be continuously accumulated and able to worsen pre-existing disease states or increase sensitivity to them. Key messages • The results indicated a significant effect of polystyrene nanoplastics on airway cell viability, ROS formation, and apoptosis. • The study helps define the harmful effects of exposure to airborne polystyrene nanoplastics on human health at the respiratory system level.