Effects of environmental conditions on latex degradation in aquatic systems

Formation of nanoparticles during accelerated UV degradation of fleece polyester textiles

Micro- and nanoplastics have emerged as critical pollutants in various ecosystems, posing potential environmental and human health risks. Washing of polyester textiles has been identified as one of the sources of nanoplastics. However, other stages of the textile life cycle may also release nanoparticles. This study aimed to examine nanoparticle release during UV degradation of polyester textiles under controlled and real-world conditions. Fleece polyester textiles were weathered under simulated sunlight for up to two months, either in air or submerged in water. We conducted bi-weekly SEM image analyses and quantified released nanoparticles using nanoparticle tracking analysis (NTA). At week 0, the fiber surface appeared smooth after prewashing. In the air group, nanoparticles appeared on the fiber surface after UV-exposure. In the group of textiles submerged in water, the surfaces developed more pits over time. The cumulative nanoparticle emission from the weathered textiles ranged from 1.4 × 1011 to 4.0 × 1011 particles per gram of fabric in the air group and from 1.6 × 1011 to 4.4 × 1011 particles per gram of fabric in the water group over two months. The predominant particle size fell into the 100 to 200 nm range. The estimated mass of the released nanoparticles was 0.06-0.26 g per gram of fabric, which is lower than the amount released during the washing of new textiles. Additionally, Scanning Transmission X-ray Microscopy (STXM) images indicated that the weathered nanoparticles underwent oxidation. Overall, the research offers valuable insights into nanoparticle formation and release from polyester textiles during UV degradation.

Abundance and characterization of microplastic pollution in the wildlife reserve, Ramsar site, recreational areas, and national park in northern Jakarta and Kepulauan Seribu, Indonesia

This is the first study to evaluate the presence and distribution of microplastics in sediments in the regions with a unique degree of complexity, such as wildlife reserve areas, a Ramsar site that connects directly to Greater Jakarta's mainland, recreational islands, and a marine national park. Microplastics of varying sizes and shapes are found in all places, with an increase trend in the abundance toward areas near to the epicenter of human activity. Comparatively to other marine protected areas, the amount of microplastics discovered is comparable; however, there is an upward trend. Season influences microplastic accumulation, with the dry season causing the greater accumulation. Small-sized microplastics and microplastics resulting from large plastic fragments were predominantly discovered. The properties of microplastics in the study region are dominated by polyethylene, polypropylene, polystyrene, polyvinyl chloride, and nylon. Additional in-depth research and waste reduction from all sources that involve all stakeholders are required to reduce the amount of contaminants entering the protected area.

Sub-10 nm Nanoparticle Detection Using Multi-Technique-Based Micro-Raman Spectroscopy

Microplastic pollution is a growing public concern as these particles are ubiquitous in various environments and can fragment into smaller nanoplastics. Another environmental concern arises from widely used engineered nanoparticles. Despite the increasing abundance of these nano-sized pollutants and the possibility of interactions with organisms at the sub cellular level, with many risks still being unknown, there are only a few publications on this topic due to the lack of reliable techniques for nanoparticle characterization. We propose a multi-technique approach for the characterization of nanoparticles down to the 10 nm level using standard micro-Raman spectroscopy combined with standard atomic force microscopy. We successfully obtained single-particle spectra from 25 nm sized polystyrene and 9 nm sized TiO2 nanoparticles with corresponding mass limits of detection of 8.6 ag (attogram) and 1.6 ag, respectively, thus demonstrating the possibility of achieving an unambiguous Raman signal from a single, small nanoparticle with a resolution comparable to more complex and time-consuming technologies such as Tip-Enhanced Raman Spectroscopy and Photo-Induced Force Microscopy.

Preliminary Study on the Role of Mangroves in Entrapping Microplastics in Tuticorin Coast of Gulf of Mannar, Southeast Coast of India

Mangroves constitute a unique and important type of coastal wetlands in tropical and subtropical zones worldwide. The abundance of microplastics (MPs) in the mangrove sediments is poorly understood. This study aimed to quantify the role of mangrove root systems in effectively entrapping MPs in the mangrove areas of Tuticorin and Punnakayal Estuary. It investigated the abundance, characteristics, and weathering patterns of MPs in different mangrove sediments. Sediment samples were collected from ten mangrove sites and two control sites without mangroves. Microplastics were extracted from mangrove sediments by density separation method, and then counted and categorized according to their shape, size, and colour. Microplastics were identified in all ten sampling sites. Punnakayal Estuary has a greater MPs concentration (27 ± 2.65 items/kg dw) than Tuticorin (9.33 ± 2.52 items/kg dw). Also, microplastic concentrations are higher in the mangrove sites than in the control sites. Most MPs are fibres with size ranges of 1-2 mm and 2-3 mm dominating. Blue and transparent are the predominant colours. Four polymers were identified, namely polyethylene (PE), polypropylene (PP), polymethyl methaacrylate (PMMA), and polyurethane (PUR). The degree of weathering was confirmed by carbonyl index and the values vary between 0.28 and 1.25 for PE and 0.6 and 1.05 for PP.

Complementary Analysis for Undetectable Microplastics from Contact Lenses to Aquatic Environments via Fourier Transform Infrared Spectroscopy

Although microplastics (MPs) are intrinsically toxic and function as vectors for organic micropollutants, their discharge from wastewater treatment plant effluents and human activity remains unknown owing to the limitations of detection and treatment technologies. It is imperative to quantify MPs from human activities involving the consumption of various plastic products. This study warns that contact lenses can generate MPs and nanoplastics (NPs) after being discharged into aquatic environments. Identification via micro-Fourier transform infrared spectroscopy revealed that the fragmented particles (from a few tens to a few hundred micrometres) could not be detected as poly(2-hydroxyl methacrylate), the component of contact lenses, owing to changes in its chemical properties. After the degradation process, the median size of the contact lens particles decreased from 313 to 85 µm. Approximately 300,600 g of contact lens waste is discharged into sewage systems daily in the United States of America (USA), where 45 million people wear contact lenses and throw away one-fifth of them every day. Contact lens waste (1 g) has the potential to release 5653.3-17,773.3 particles of MPs. This implies that the currently reported MP amounts in the environmental matrix exclude significant amounts of MPs and NPs from discharged contact lenses. The identification method should be examined, and a registration of the disposal process should be established.

A systematic review of microplastics in the environment: Sampling, separation, characterization and coexistence mechanisms with pollutants

Microplastics (<5 mm) (MPs) are widely distributed throughout the world, and their accumulation and migration in the environment have caused health and safety concerns. Currently, most of the reviewed literatures mainly focus on the distribution in various environmental media, adsorption mechanisms with different pollutants, and characterization of MPs. Therefore, the present review mainly highlights the characterization techniques of MPs and the underlying mechanisms of their combination with conventional coexisting substances (heavy metals, organic pollutants, and nutrients). We observed that massive MP pollution has been found in many areas, especially in Africa, Asia, India, South Africa, North America and Europe. The separation methods of MPs in different environmental media are basically similar, including sampling, pre-treatment, flotation, filtration and digestion. The combination of multiple characterization technologies can more precisely identify the shape, abundance, colour, and particle size of MPs. Notably, although recent reports have confirmed that MPs can act as carriers of heavy metals and carry them into organisms to cause harm, MPs have different adsorption and desorption characteristics for various heavy metals. The adsorption capacity of organic pollutants onto MPs is closely related to their hydrophobicity, specific surface area and functional group characteristics. The relative abundance of MPs in sediments and lakes had a significantly positive correlation with the mass concentration of total nitrogen in lake water, but this finding still needs to be further verified. Based on current research, we suggest that future MP research should focus on characterization technology, environmental migration, ecological effects, health risks and degradation methods.

Atmospheric micro (nano) plastics: future growing concerns for human health

ABSTRACT

Plastics are an integral but largely inconspicuous part of daily human routines. The present review paper uses cross-disciplinary scientific literature to examine and assess the possible effects of nanoplastics (NPs) concerning microplastics (MPs) on human health and summarizes crucial areas for future research. Although research on the nature and consequences of MPs has seen a substantial rise, only limited studies have concentrated on the atmospheric nanosized polymeric particles. However, due to the intrinsic technological complications in separating and computing them, their existence has been difficult to determine correctly. There is a consensus that these are not only existing in the environment but can get directly released or as the outcome of weathering of larger fragments, and it is believed to be that combustion can be the tertiary source of polymeric particles. NPs can have harmful consequences on human health, and their exposure may happen via ingestion, inhalation, or absorption by the skin. The atmospheric fallout of micro (nano) plastics may be responsible for contaminating the environment. Apart from this, different drivers affect the concentration of micro (nano) plastics in every environment compartment like wind, water currents, vectors, soil erosion, run-off, etc. Their high specific surface for the sorption of organic pollutions and toxic heavy metals and possible transfer between organisms at different nutrient levels make the study of NPs an urgent priority. These NPs could potentially cause physical damage by the particles themselves and biological stress by NPs alone or by leaching additives. However, there is minimal understanding of the occurrence, distribution, abundance, and fate of NPs in the environment, partially due to the lack of suitable techniques for separating and identifying NPs from complex environmental matrices.

HIGHLIGHTS

Micro (nano) plastics generated may reach the soil, water, and atmospheric compartments.Atmospheric currents serve as a way to transport, leading to micro (nano) plastics pollution.Exposure to micro (nano) plastics may happen via ingestion, inhalation, or absorption by the skin.Nanoplastics may be environmentally more harmful than other plastic particles; the focus should be on defining the exact size range.Visual classification of micro (nano) plastics is poor in reliability and may also contribute to microplastics being misidentified.

Generation and consequence of nano/microplastics from medical waste and household plastic during the COVID-19 pandemic

Since the end of 2019, the world has faced a major crisis because of the outbreak of COVID-19 disease which has created a severe threat to humanity. To control this pandemic, the World Health Organization gave some guidelines like wearing PPE (personal protective equipment) (e.g., face masks, overshoes, gloves), social distancing, hand hygiene and shutting down all modes of public transport services. During this pandemic, plastic products (e.g., household plastics, PPE and sanitizer bottles) have substantially prevented the spread of this virus. Since the outbreak, approximately 1.6 million tons of plastic waste have been generated daily. However, single-use PPE like face masks (N95), surgical masks and hand gloves contain many non-biodegradable plastics materials. These abandoned products have created a huge number of plastic debris which ended up as microplastics (MPs) followed by nanoplastics (NPs) in nature that are hazardous to the eco-system. These MPs and NPs also act as vectors for the various pathogenic contaminants. The goal of this review is to offer an extensive discussion on the formation of NPs and MPs from all of these abandoned plastics and their long-term impact on the environment as well as human health. This review paper also attempts to assess the present global scenario and the main challenge of waste management to reduce the potential NP/MPs pollution to improve the eco-systems.

The toxic effects of polystyrene microplastics on freshwater algae Chlorella pyrenoidosa depends on the different size of polystyrene microplastics

Microplastics (MPs) are persistent environmental contaminants. The toxic effects of MPs on aquatic organisms have raised increasing concerns, but their toxic effects on aquatic phytoplankton has not been thoroughly investigated. In the present study, the toxic effects of two sizes MPs (1 μm and 5 μm) on Chlorella pyrenoidosa at 2, 10, 50 mg/L were explored for 1, 5, 10 days. The growth ratio, photosynthetic pigments content, extracellular polymeric substances content, soluble protein content, MDA content and relative expression of genes related to photosynthesis and energy metabolism were measured. These results indicated that 1 μm MP could significantly inhibit the growth of C. pyrenoidosa. Compared with the control group, 1 μm MP significantly reduced the photosynthetic pigment content, induced oxidative stress and disrupted the cell membrane integrity of C. pyrenoidosa. At the molecular level, 1 μm MP altered the transcript levels of genes related to photosynthesis and energy metabolism. Scanning electron microscopy and fluorescent images showed that MPs aggregation with C. pyrenoidosa may be the main reason for the toxic effects of MPs. These results will provide new insight into the toxicity of different MPs on aquatic phytoplankton, and evaluate the risks caused by MPs in aquatic environments.

Microplastics in urban waters and its effects on microbial communities: a critical review

Microplastic (MP) pollution is one of the emerging threats to the water and terrestrial environment, forcing a new environmental challenge due to the growing trend of plastic released into the environment. Synthetic and non-synthetic plastic components can be found in rivers, lakes/reservoirs, oceans, mountains, and even remote areas, such as the Arctic and Antarctic ice sheets. MPs' main challenge is identifying, measuring, and evaluating their impacts on environmental behaviors, such as carbon and nutrient cycles, water and wastewater microbiome, and the associated side effects. However, until now, no standardized methodical protocols have been proposed for comparing the results of studies in different environments, especially in urban water and wastewater. This review briefly discusses MPs' sources, fate, and transport in urban waters and explains methodological uncertainty. The effects of MPs on urban water microbiomes, including urban runoff, sewage wastewater, stagnant water in plumbing networks, etc., are also examined in depth. Furthermore, this study highlights the pathway of MPs and their transport vectors to different parts of ecosystems and human life, particularly through mediating microbial communities, antibiotic-resistant genes, and biogeochemical cycles. Overall, we have briefly highlighted the present research gaps, the lack of appropriate policy for evaluating microplastics and their interactions with urban water microbiomes, and possible future initiatives.

Neurotoxic effects of different sizes of plastics (nano, micro, and macro) on juvenile common carp (Cyprinus carpio)

Using common carp as a model, we assessed the effects of polyethylene (PE) plastics on the brain. We measured activity of acetylcholinesterase (AChE), monoamine oxidase (MAO), and the content of nitric oxide (NO) in carp brain following exposure to 100 mg/L of either macroplastics (MaP), microplastics (MPs), or nanoplastic (NPs) for 15 days compared to an unexposed group. Following exposure, each biochemical biomarker was reduced 30–40%, with a higher magnitude of change corresponding to the smaller size of the particles (NPs > MPs > MaPs). In the carp tectum, exposure for 15 days to plastic particles caused varying degrees of necrosis, fibrosis, changes in blood capillaries, tissue detachment, edema, degenerated connective tissues, and necrosis in large cerebellar neurons and ganglion cells. In the carp retina, there was evidence for necrosis, degeneration, vacuolation, and curvature in the inner layer. Here we provide evidence that exposure to plastic particles can be associated with neurotoxicity in common carp.

Microplastics as Contaminants in Water Bodies and Their Threat to the Aquatic Animals: A Mini-Review

Microplastics (MPs), which are particles with a diameter of less than 5 mm, have been extensively studied due to their serious global pollution. Typically, MPs in water originate from terrestrial input. A number of studies have reported the presence of MPs as a stressor in water environments worldwide, and their potential threat to the aquatic animals, affecting the growth, oxidative stress responses, body composition, histopathology, intestinal flora, and immune and reproduction systems. During the plastic degradation process, a large variety of toxic substances are released. MPs have been proposed to be the carriers of toxic chemicals and harmful microorganisms. A study of the literature on MP pollution and stress on the aquatic animals associated with MPs was carried out.

Current status and trends of research on microplastic fugacity characteristics and pollution levels in mangrove wetlands

Microplastics have been widely detected in the environment, while mangrove wetlands are considered barriers to land-based plastic transport to the ocean, requiring special attention. However, the current literature is distributed and broad besides limited information on the fate characteristics and pollution levels. This study uses a systematic literature review method to analyze the current research status and future trends. In this study, the literature is summarized and concluded that Characteristics including color, shape, size, polymer chemistry and surface microstructure are the basic information for microplastic research in mangrove wetlands. Size is the key to studying distribution and convergence without international standards. The shape is vital to study its sources and environmental processes. Color affects biological predation and is important information for studying ecological risk. The chemical composition of plastics is the key to studying microplastics’ fingerprint information, source, and sink. The surface microstructure is an important basis for studying adsorption behavior and aging processes. Mangrove microplastic studies in China are mainly on the southern and southeastern coasts, and microplastic pollution is more severe in Fujian, Guangdong, and Guangxi than in Hainan. In contrast, studies on mangrove microplastics abroad are mainly concentrated in Southeast Asia, the Middle East, and South America. Overall, microplastic contamination was detected in the major distribution areas of mangroves worldwide and was correlated with mangrove density and human activities.

Nano-ecotoxicology in a changing ocean

The ocean faces an era of change, driven in large by the release of anthropogenic CO2, and the unprecedented entry of pollutants into the water column. Nanomaterials, those particles < 100 nm, represent an emerging contaminant of environmental concern. Research on the ecotoxicology and fate of nanomaterials in the natural environment has increased substantially in recent years. However, commonly such research does not consider the wider environmental changes that are occurring in the ocean, i.e., ocean warming and acidification, and occurrence of co-contaminants. In this review, the current literature available on the combined impacts of nanomaterial exposure and (i) ocean warming, (ii) ocean acidification, (iii) co-contaminant stress, upon marine biota is explored. Here, it is identified that largely co-stressors influence nanomaterial ecotoxicity by altering their fate and behaviour in the water column, thus altering their bioavailability to marine organisms. By acting in this way, such stressors, are able to mitigate or elevate toxic effects of nanomaterials in a material-specific manner. However, current evidence is limited to a relatively small set of test materials and model organisms. Indeed, data is biased towards effects upon marine bivalve species. In future, expanding studies to involve other ecologically significant taxonomic groups, primarily marine phytoplankton will be highly beneficial. Although limited in number, the available evidence highlights the importance of considering co-occurring environmental changes in ecotoxicological research, as it is likely in the natural environment, the material of interest will not be the sole stressor encountered by biota. As such, research examining ecotoxicology alongside co-occurring environmental stressors is essential to effectively evaluating risk and develop effective long-term management strategies.

Nanoplastics in Aquatic Environments: Impacts on Aquatic Species and Interactions with Environmental Factors and Pollutants

Plastic production began in the early 1900s and it has transformed our way of life. Despite the many advantages of plastics, a massive amount of plastic waste is generated each year, threatening the environment and human health. Because of their pervasiveness and potential for health consequences, small plastic residues produced by the breakdown of larger particles have recently received considerable attention. Plastic particles at the nanometer scale (nanoplastics) are more easily absorbed, ingested, or inhaled and translocated to other tissues and organs than larger particles. Nanoplastics can also be transferred through the food web and between generations, have an influence on cellular function and physiology, and increase infections and disease susceptibility. This review will focus on current research on the toxicity of nanoplastics to aquatic species, taking into account their interactive effects with complex environmental mixtures and multiple stressors. It intends to summarize the cellular and molecular effects of nanoplastics on aquatic species; discuss the carrier effect of nanoplastics in the presence of single or complex environmental pollutants, pathogens, and weathering/aging processes; and include environmental stressors, such as temperature, salinity, pH, organic matter, and food availability, as factors influencing nanoplastic toxicity. Microplastics studies were also included in the discussion when the data with NPs were limited. Finally, this review will address knowledge gaps and critical questions in plastics’ ecotoxicity to contribute to future research in the field.

Microplastics in Wastewater by Washing Polyester Fabrics

Microplastics have become one of the most serious environmental hazards today, raising fears that concentrations will continue to rise even further in the near future. Micro/nanoparticles are formed when plastic breaks down into tiny fragments due to mechanical or photochemical processes. Microplastics are everywhere, and they have a strong tendency to interact with the ecosystem, putting biogenic fauna and flora at risk. Polyester (PET) and polyamide (PA) are two of the most important synthetic fibres, accounting for about 60% of the total world fibre production. Synthetic fabrics are now widely used for clothing, carpets, and a variety of other products. During the manufacturing or cleaning process, synthetic textiles have the potential to release microplastics into the environment. The focus of this paper is to explore the main potential sources of microplastic pollution in the environment, providing an overview of washable polyester materials.

Toward a Framework for Environmental Fate and Exposure Assessment of Polymers

Development of risk-assessment methodologies for polymers is an emerging regulatory priority to prevent negative environmental impacts; however, the diversity and complexity of polymers require adaptation of existing environmental risk-assessment approaches. The present review discusses the challenges and opportunities for the fate and exposure assessment of polymers in the context of regulatory environmental risk assessment of chemicals. The review discusses the applicability and adequacy for polymers of existing fate parameters used for nonpolymeric compounds and proposes additional parameters that could inform the fate of polymers. The significance of these parameters in various stages of an exposure-assessment framework is highlighted, with classification of polymers as solid or dissolved being key for identification of those parameters most relevant to environmental fate. Considerations to address the key limitations and knowledge gaps are then identified and discussed, specifically the complexity of polymer identification, with the need for characterization of the most significant parameters for polymer grouping and prioritization; the complexity of polymer degradation in the environment, with the need to incorporate the fate and hazards of degradation products into risk assessment; the requirement for development and standardization of analytical methods for characterization of polymer fate properties and degradation products; and the need to develop exposure modeling approaches for polymers. Environ Toxicol Chem 2022;41:515-540. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Cell size matters: Nano- and micro-plastics preferentially drive declines of large marine phytoplankton due to co-aggregation

Marine plastic pollution represents a key environmental concern. Whilst ecotoxicological data for plastic is increasingly available, its impact upon marine phytoplankton remains unclear. Owing to their predicted abundance in the marine environment and likely interactions with phytoplankton, here we focus on the smaller fraction of plastic particles (~50 nm and ~2 µm polystyrene spheres). Exposure of natural phytoplankton communities and laboratory cultures revealed that plastic exposure does not follow traditional trends in ecotoxicological research, since large phytoplankton appear particularly susceptible towards plastics exposure despite their lower surface-to-volume ratios. Cell declines appear driven by hetero-aggregation and co-sedimentation of cells with plastic particles, recorded visually and demonstrated using confocal microscopy. As a consequence, plastic exposure also caused disruption to photosynthetic functioning, as determined by both photosynthetic efficiency and high throughput proteomics. Negative effects upon phytoplankton are recorded at concentrations orders of magnitude above those estimated in the environment. Hence, it is likely that impacts of NPs and MPs are exacerbated at the high concentrations typically used in ecotoxicological research (i.e., mg L-1).

Review of ecotoxicological studies of widely used polystyrene nanoparticles

With polystyrene nanoparticles being widely used in various applications, there is a great need for deeper knowledge on the safety, fate and biological effects of these particles on both individual living organisms and the whole ecosystems. Due to this, there is a growing interest in performing ecotoxicological studies using model plastic nanoparticles, and consequently it generates an increasing number of published papers describing the negative impact on wildlife caused by such nanoparticles. Polystyrene is the most studied nanosized plastic, therefore this review focuses on research conducted with manufactured polystyrene nanoparticles. The aim of the present article is to provide a critical methodological outline of the existing ecotoxicological studies on the effects of polystyrene nanoparticles on aquatic organisms. Going through the published articles, we noted that particle characterization especially in the test medium, can be improved. The analysis also highlights the importance of purifying the polystyrene nanoparticles before studying its toxicity. Furthermore, the size characterization of such nanoparticles is underemphasized, and in future studies, authors should consider including more techniques to achieve this goal. Finally, short-term or direct exposure scenarios do not add the most environmentally relevant knowledge in terms of the toxicity caused by polystyrene nanoparticles.

Understanding the fate of nano-plastics in wastewater treatment plants and their removal using membrane processes

Nanoplastics (NPs) have become a major environmental issue due to their adverse effect on the water environment. Wastewater treatment plant (WWTP) is considered as one of the main sources for breaking down of larger-sized plastic debris and microplastics (MPs) into NPs. This study aims to provide a comprehensive understanding of NPs generation in the WWTPs, their physiochemical characteristics and interaction with the WWTPs. It is found that cracking is the major mechanism of plastics fragmentation in the WWTPs. This review also discusses the current membrane process used for NPs removal. It is found that conventional membrane processes are ineffective as they are not designed for NPs removal and fouling is a major obstacle for its application. Therefore, this study concludes by providing an outlook of developing a bio-nanofiltration process that can be used as a tertiary treatment for removing NPs and other components present in water. Such a process can produce NPs-free water for non-potable use or safe discharge into open waterways.

Polystyrene microplastics induce apoptosis via ROS-mediated p53 signaling pathway in zebrafish

Microplastic (MP) pollution is ubiquitous and has become an emerging threat to aquatic biota. Recent scientific reports have recorded their toxic impacts at the cellular and organism levels, but the underlying molecular mechanism of their toxicity remains unclear. The present study elucidates an array of molecular events underlying apoptosis in the gills of polystyrene microplastics (PS-MPs) exposed zebrafish (Danio rerio). PS-MPs at different concentrations (10 and 100 μg L^-1) induced the reactive oxygen species (ROS) generation, in turn affecting the oxidative and immune defense mechanism. The expression profile of antioxidant genes cat, sod1, gpx1a and gstp1 were altered significantly. PS-MPs also significantly inhibited the neurotransmission in zebrafish. In addition, the PS-MPs exposure upregulated the expression of p53, gadd45ba, and casp3b resulting in apoptosis. We demonstrate that PS-MPs significantly upregulate the transcriptional pattern of tnfa and ptgs2a which are essential gene markers in inflammatory mechanism. Further, the oxidative damage induced by PS-MPs exposure could lead to cytological damage resulting in altered lamellar structures, capillary dilation, and necrosis in gill histomaps. In conclusion, the findings of this work strongly suggest that PS-MPs induce dose-and time-dependent ROS mediated apoptotic responses in zebrafish. Furthermore, the physiological responses observed in the gills correlate with the above observations and helps in unravelling the potential molecular mechanism underpinning the PS-MPs toxicity in zebrafish.

The Effect of Poly (Ethylene glycol) Emulation on the Degradation of PLA/Starch Composites

As a hydrophilic renewable polymer, starch has been widely used in biocompatible plastics as a filler for more than two decades. The present study aimed at investigating the effects of polyethylene glycol (PEG), as a plasticizer, on the physicochemical properties of a hybrid composite-polylactic acid (PLA) and thermoplastic starch (TPS). A solvent evaporation process was adopted to gelatinize the starch and disparate PEG contents ranging from 3 to 15 wt.% (with respect to the sample weight) were examined. It was revealed that the increase in the PEG content was accompanied by an increment in the starch gelatinization degree. Referring to the microstructural analyses, the TPS/PLA mixture yielded a ductile hybrid composite with a fine morphology and a uniform phase. Nevertheless, two different solvents, including acetone and ethanol, were used to assess if they had any effect on the hybrid's morphology, tensile strength and thermal properties. It was found that ethanol culminated in a porous hybrid composite with a finer morphology and better starch distribution in the PLA structure than acetone. As the result of PEG addition to the composite, the crystallinity and tensile strength were decreased, whereas the elongation increased. The hydrolytic degradation of samples was assessed under different pH and thermal conditions. Moreover, the microbial degradation of the PLA/TPS hybrid composite containing different PEG molar fractions was investigated in the soil for 45 days. The rate of degradation in both hydrolytic and biodegradation increased in the samples with a higher amount of PEG with ethanol solvent.

Plastic particles in soil: state of the knowledge on sources, occurrence and distribution, analytical methods and ecological impacts

Increased production and use of plastics has resulted in growth in the amount of plastic debris accumulating in the environment, potentially fragmenting into smaller pieces. Fragments <5 mm are typically defined as microplastics, while fragments <0.1 μm are defined as nanoplastics. Over the past decade, an increasing number of studies have reported the occurrence and potential hazards of plastic particles in the aquatic environment. However, less is understood about plastic particles in the terrestrial environment and specifically how much plastic accumulates in soils, the possible sources, potential ecological impacts, interaction of plastic particles with the soil environment, and appropriate extraction and analytical techniques for assessing the above. In this review, a comprehensive overview and a critical perspective on the current state of knowledge on plastic pollution in the soil environment is provided: detailing known sources, occurrence and distribution, analytical techniques used for identification and quantification and the ecological impacts of particles on soil. In addition, knowledge gaps are identified along with suggestions for future research.

A systematic protocol of microplastics analysis from their identification to quantification in water environment: A comprehensive review

With microplastics (MPs) being detected in aquatic environments, numerous studies revealed that they caused severe environmental issues, including damage to ecosystems and human health. MPs transport persistent organic pollutants by adsorbing them, and in nanoplastics this phenomenon is exacerbated by increased surface area. Despite their environmental risk, systematic protocol for qualitative and quantitative analysis are yet to be established in environmental analytical chemistry. Current analytical technologies on MP identification have technological limits with regard to detecting small sized particles (<1 µm), underestimation of MPs with organic contaminants, and physico-chemically altered particles by weathering and photo degradation. According to the published works, MPs are spread in living organisms through the food web, and are even detected in bottled water. To determine its eco-toxicity and removal by biodegradation, its accuracy, reliability, and reproducibility should be ensured by establishing a systematic protocol of MP identification. This review compares procedures, applicability, and limitations of Fourier transform infrared spectroscopy, Raman spectroscopy, and thermo-analytical methods for identifying MPs. Finally, it suggests systematic protocols for MPs analysis.

Characterization of microplastics in mangrove sediment of Muara Angke Wildlife Reserve, Indonesia

An investigation of microplastic abundance and its characteristics was conducted in Muara Angke Wildlife Reserve, a relic mangrove forest in the Jakarta metropolitan, to contribute to marine microplastics' national data inventory. Microplastics were found in all the stations, with an average of 28.09 ± 10.28 particles per kg of dry sediment (n kg^-1). Sediments in the outside mangrove area contained more microplastics than the inside area. Foam form was the most dominant in all the samples and was found more abundant on the outside. More than half of microplastics were of size <1000 μm, and nearly 50% were polystyrenes. This polymer is widely used for food packaging, which is prone to be fragmented. Polypropylene and polyethylene form another 50% of microplastics, which are widely used for textiles and fishing gears. As Jakarta is the largest city in Indonesia, this microplastic dataset may be the benchmark for other mangroves around the country.

Effects of microplastics and nanoplastics on marine environment and human health

Microplastics (MPs) with an average size of less than 5 mm, along with nanoplastics (NPs) of an average size of fewer than 0.1 μm are the result of huge plastic waste fragmentation or straight environmental emissions. Pollution from micro- and nanoplastics is a worldwide paradigm that raises environmental and human health concerns. They may also comprise very harmful chemicals that are implemented in plants and animals when MPs/NPs are used that may lead to higher accumulation of these compounds in food chains. In addition, higher surface area-to-volume ratio, characteristic of MPs/NPs can contribute to their potentially harmful impact as other pollutants, like continuous organic contaminants, can also be bio-accumulated and adsorbed. A complex issue correlated with MPs/NPs is their ability to absorb and interact with other common pollutants in the environment, such as metals, pharmaceuticals, and other contaminants. Thus, MPs/NPs can directly influence on destiny and toxicity of these substances to the environment and organisms. In this review, first, we introduce possible sources and formation, their destinies, and environmental impact of MPs/NPs and then explain feasible paths of all these particles entering the human body. Then, the review highlights the effect of MPs/NPs on human health. Finally, it provides a brief summary of the potential as well as the neurological toxicity of MPs/NPs.

A Meta-analysis of Ecotoxicological Hazard Data for Nanoplastics in Marine and Freshwater Systems

There is emerging concern about the potential health and environmental impacts of nanoplastics in the environment. Information on exposure has been lacking, but a growing amount of ecotoxicological hazard data is now available, allowing a hazard assessment to be conducted for nanoplastics in freshwater and marine systems. Based on a critical evaluation of published studies and the construction of probabilistic species sensitivity distributions (PSSDs), we present a comprehensive, state-of-the-art understanding of nanoplastic ecotoxicity. Different freshwater and marine datasets were constructed based on different data quality levels, and for each of the datasets, PSSDs were built for both mass- and particle number-based concentrations. Predicted no-effect concentrations (PNECs) were then extracted from the PSSDs. We report PNECs at 99 and 72 μg L-1 , respectively, for the freshwater and marine dataset after the removal of data measured in the presence of sodium azide (NaN3 ), which is considered to be a major interfering factor in the ecotoxicity testing of nanoplastics. By comparing the PNECs, we found that nanoplastics are less toxic than microplastics and many engineered nanomaterials. In addition, the effects of size and polymer type on toxicity were also statistically tested. We observed no significant difference in ecotoxicity for nanoplastics of different sizes, whereas polystyrene nanoplastics were significantly more toxic than all other tested nanoplastics. In conclusion, the results we present provide a comprehensive description of nanoplastic ecotoxicity based on current knowledge. The results constitute a fundamental step toward an environmental risk assessment for nanoplastics in freshwater and marine systems. Environ Toxicol Chem 2020;39:2588-2598. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Degradation of nanoplastics in the environment: Reactivity and impact on atmospheric and surface waters

Microplastics (MPs) and nanoplastics (NPs) are ubiquitous and contaminate soil, surface waters, atmospheric aerosol, precipitations, indoor and outdoor environments. However, the occurrence, transformation and fate of NPs in the environment are still unclear. In this work, polystyrene nanoparticles (PS-NPs) are used as a proxy of NPs to study their reactivity and potential impact on atmospheric and surface waters. In particular, the reactivity with hydroxyl radicals (OH) in the aqueous phase is investigated. For the first time, a reactivity constant for the reaction of NPs with OH is measured, strongly dependent on the exposed particle surface area of NPs. Degradation products (short chain carboxylic acids and aromatic compounds), obtained by direct and OH-mediated photolysis of PS-NPs suspensions, are identified by mass spectrometry. Irradiation of a PS-NPs suspension under natural sunlight for 1 year has shown the formation of formic acid and organic compounds similar to those found in riverine and cloud dissolved organic matter, which could contribute significantly to the dissolved organic matter in the aqueous phase.

Atmospheric Micro and Nanoplastics: An Enormous Microscopic Problem

Atmospheric plastic pollution is now a global problem. Microplastics (MP) have been detected in urban atmospheres as well as in remote and pristine environments, showing that suspension, deposition and aeolian transport of MP should be included and considered as a major transport pathway in the plastic life cycle. This work reports an up to date review of the experimental estimation of deposition rate of MP in rural and urban environment, also analyzing the correlation with meteorological factors. Due to the limitations in sampling and instrumental methodology, little is known about MP and nanoplastics (NP) with sizes lower than 50 µm. In this review, we describe how NP could be transported for longer distances than MP, making them globally present and potentially more concentrated than MP. We highlight that it is crucial to explore new methodologies to collect and analyze NP. Future research should focus on the development of new technologies, combining the existent knowledge on nanomaterial and atmospheric particle analysis.

On optical sensing of surface roughness of flat and curved microplastics in water

The growth of microplastic (MP) pollution is of increasing concern and represents a global challenge. In situ detection of these small particles is difficult because of their sizes, shapes, transparency or translucency, surface texture and ambient conditions. We propose and demonstrate the use of a prototype optical sensor to detect flat, nearly flat, curved and rough MPs prepared from commercial polyethylene terephthalate (PET) plastics and PET bottles in water. The prototype measures the specular reflection of a laser radiation incident on MPs, with a photodiode, and the transmitted laser speckle pattern, with a charge-coupled device (CCD) camera. The presence of the MPs as well as the optical surface roughness are determined from the specular reflection. Additionally, the so-called speckle contrast calculated from the speckle pattern, as a promising tool, is used to rank the rough MPs according to the different average surface roughness, to approximately twice the wavelength of the probing light. The novel application of laser speckle contrast and the optical roughness estimation allows the description of MP surface roughness in water. Moreover, in combination with earlier studies, these results, therefore, pave a way for the complete and a relatively easier description of MPs properties optical and also advances our step towards the development of simple and robust optical monitoring techniques for micro and nanoplastics in open and wastewater.

Fragmentation of plastic objects in a laboratory seawater microcosm

We studied the fragmentation of conventional thermoplastic and compostable plastic items in a laboratory seawater microcosm. In the microcosm, polyurethane foams, cellulose acetate cigarette filters, and compostable polyester and polylactic acid items readily sank, whereas polyethylene air pouches, latex balloons, polystyrene foams and polypropylene cups remained afloat. Microbial biofilms dominated by Cyanobacteria, Proteobacteria, Planctomycetes and Bacteriodetes grew on the plastics, and caused some of the polyethylene items to sink to the bottom. Electrical resistances (ER) of plastic items decreased as function of time, an indication that seawater had penetrated into microscopic crevices in the plastic that had developed over time. Rate constants for ER decrease in polyethylene items in the microcosm were similar to tensile elongation decrease of polyethylene sheets floating in sea, measured previously by others. Weight loss of plastic items was ≤ 1% per year for polyethylene, polystyrene and polypropylene, 3-5% for latex, polyethylene terephthalate and polyurethane, 15% for cellulose acetate, and 7-27% for polyester and polylactic acid compostable bags. The formation of microplastics observed in the microcosm was responsible for at least part of the weight loss. This study emphasizes the need to obtain experimental data on plastic litter degradation under conditions that are realistic for marine environments.

Microplastics release precursors of chlorinated and brominated disinfection byproducts in water

Microplastics (MPs) are prevalent global pollutants that are being detected in aquatic ecosystems and drinking water sources around the world. In addition to plastic polymers, MPs contain various chemical substances (known as "additives") that can leach and risk water quality. In this paper, we investigated for the first time the potential release of disinfection byproducts (DBPs) precursors when MPs are exposed to hydrolysis and/or degradation by simulated sunlight. Seventeen MPs with seven different polymer types were collected either as commercial products (e.g. drinking water bottles, shopping bags, recycled plastics, etc.) or pure/virgin polymers. Results showed high release of dissolved organic carbon (DOC) from five MP samples and a significant increase in bromide concentrations from four MPs. DBPs formation potential (DBPFP) experiments with MPs' leachates showed higher concentrations of chlorinated trihalomethanes (THMs), haloacetonitriles (HANs), and total organic halogens (TOX) in three samples, while a significant shift to brominated DBPs was observed in samples containing bromide. Extending the leaching experiments to four consecutive cycles showed that the leaching of DOC and DBPs' precursor significantly decreased after the second leaching cycle. Further analysis revealed that the reactivity of the leached DOC - indicated by THMFP yields - was comparable to those of several raw waters that supply drinking water treatment plants. The leached THMs and TOX from MPs that were exposed to UVA irradiation were in general higher than MPs that were run under dark conditions.

Influence of polystyrene microplastics on the growth, photosynthetic efficiency and aggregation of freshwater microalgae Chlamydomonas reinhardtii

Microplastics are ubiquitous in aquatic ecosystems worldwide, but knowledge on their impacts on phytoplankton, especially freshwater microalgae, is still limited. To investigate this issue, microalgae Chlamydomonas reinhardtii was exposed to polystyrene (PS) microplastics with 4 concentration gradients (5, 25, 50 and 100 mg/L), and the growth, chlorophyll a fluorescence, photosynthetic activities (Fv/Fm), the contents of malondialdehydes (MDA), soluble proteins, extracellular polymeric substances (EPS) and settlement rate were accordingly measured. Results showed that the density of microalgae decreased as the increase of PS microplastics concentrations, and the highest inhibitory rate (IR) was 45.8% on the 7th day under the concentration of 100 mg/L. The high concentration (100 mg/L) of microplastics evidently inhibited the content of EPS released by microalgae into the solution. PS under all dosages tested could reduce both the chlorophyll a fluorescence yields and photosynthetic activities. The scanning electron microscope (SEM) images demonstrated that microplastic beads were wrapped on the surface of microalgae and damaged their membranes, which could suggest the reduction of photosynthetic activities and the increase of soluble proteins and MDA content. The results also showed that PS microplastics could inhibit the settlement of microalgae at the later stage, which also indicated the recovery of microalgae from the toxic environment. Our findings will contribute to understanding the effects of microplastics on freshwater microalgae, as well as evaluating the possible influences of microplastics on aquatic ecosystems.

Micro- and nanoplastic toxicity on aquatic life: Determining factors

Plastic pollution has become a major environmental concern due to its omnipresence and degradation to smaller particles. The potential toxicological effects of micro- and nanoplastic on biota have been investigated in a growing number of exposure studies. We have performed a comprehensive review of the main determining factors for plastic particle toxicity in the relevant exposure systems, from publications until including the year 2018. For a focused scope, effects of additives or other pollutants accumulated by the plastic particles are not included. In summary, current literature suggests that plastic particle toxicity depends on concentration, particle size, exposure time, particle condition, shape and polymer type. Furthermore, contaminant background, food availability, species, developmental stage and sex have major influence on the outcome of plastic particles exposures. Frequently reported effects were on body and population growth, energy metabolism, feeding, movement activity, physiological stress, oxidative stress, inflammation, the immune system, hormonal regulation, aberrant development, cell death, general toxicity and altered lipid metabolism. Several times reported were increased growth and food consumption, neuro-, liver- or kidney pathology and intestinal damage. Photosynthesis disruption was reported in studies investigating effects on phytoplankton. For the currently unquantified plastic particles below 10 μm, more toxic effects were reported in all aquatic life, as compared to plastic particles of larger size.

Nanoplastics Promote Microcystin Synthesis and Release from Cyanobacterial Microcystis aeruginosa

Although the fate of nanoplastics (<100 nm) in freshwater systems is increasingly well studied, much less is known about its potential threats to cyanobacterial blooms, the ultimate phenomenon of eutrophication occurrence worldwide. Previous studies have evaluated the consequences of nanoplastics increasing the membrane permeability of microbes, however, there is no direct evidence for interactions between nanoplastics and microcystin; intracellular hepatotoxins are produced by some genera of cyanobacteria. Here, we show that the amino-modified polystyrene nanoplastics (PS-NH₂) promote microcystin synthesis and release from Microcystis aeruginosa, a dominant species causing cyanobacterial blooms, even without the change of coloration. We demonstrate that PS-NH₂ inhibits photosystem II efficiency, reduces organic substance synthesis, and induces oxidative stress, enhancing the synthesis of microcystin. Furthermore, PS-NH₂ promotes the extracellular release of microcystin from M. aeruginosa via transporter protein upregulation and impaired cell membrane integrity. Our findings propose that the presence of nanoplastics in freshwater ecosystems might enhance the threat of eutrophication to aquatic ecology and human health.

Aggregation and stability of nanoscale plastics in aquatic environment

The widespread use and release of plastics in nature have raised global concerns about their impact on public health and the environment. While much research has been conducted on macro- and micro-sized plastics, the fate of nanoscale plastics remains unexplored. In this study, the aggregation kinetics and stability of polyethylene and polystyrene nanoscale plastics were investigated over a wide range of aquatic chemistries (pH, salt types (NaCl, CaCl_2, MgCl₂), ionic strength) relevant to the natural environment. Results showed that salt types and ionic strength had significant effects on the stability of both polyethylene and polystyrene nanoscale plastics, while pH had none. Aggregation and stability of both polyethylene and polystyrene nanoscale plastics in the aquatic environment followed colloidal theory (DLVO theory and Schulze-Hardy rule), similar to other colloidal particles. The critical coagulation concentration (CCC) values of polyethylene nanoscale plastics were lower for CaCl₂ (0.1 mM) compared to NaCl (80 mM) and MgCl₂ (3 mM). Similarly, CCC values of polystyrene nanospheres were 10 mM for CaCl₂, 800 mM for NaCl and 25 mM for MgCl₂. It implies that CaCl₂ destabilized both polyethylene and polystyrene nanoscale plastics more aggressively than NaCl and MgCl₂. Moreover, polystyrene nanospheres are more stable in the aquatic environment than polyethylene nanoscale plastics. However, natural organic matter improved the stability of polyethylene nanoscale plastics in water primarily due to steric repulsion, increasing CCC values to 0.4 mM, 120 mM and 8 mM for CaCl_2, NaCl and MgCl₂ respectively. Stability studies with various water conditions demonstrated that polyethylene nanoscale plastics will be fairly stable in the natural surface waters. Conversely, synthetic surface water, wastewater, seawater and groundwater rapidly destabilized polyethylene nanoscale plastics. Overall, our findings indicate that significant aqueous transport of nanoscale plastics will be possible in natural surface waters.

Sorption of tri-n-butyl phosphate and tris(2-chloroethyl) phosphate on polyethylene and polyvinyl chloride microplastics in seawater

Microplastics and organophosphate esters are ubiquitous pollutants in the marine environment. However, their interactions are poorly understood. In the present study, the sorptions of tri-n-butyl phosphate (TnBP) and tris(2-chloroethyl) phosphate (TCEP) on polyethylene (PE) and polyvinyl chloride (PVC) microplastics in seawater were investigated. Results indicated that the first-order kinetic model and pseudo-second-order were suitable to describe PE and PVC microparticles for the adsorption of the two organophosphate esters, respectively. The adsorption capacity increased with the decrease in particle size. The highest adsorption capacity appeared at 15 °C. The equilibrium isotherms data for the adsorption of the two organophosphate esters on PVC and PE microplastics were best fitted with Freundlich isotherm model and Langmuir isotherm model, respectively. The pore-filling mechanism involved in the adsorption of TnBP and TCEP on PVC microplastics and the monolayer coverage was the predominant mechanism for the adsorption of TnBP and TCEP on PE microplastics.

Adsorption behavior of organic pollutants and metals on micro/nanoplastics in the aquatic environment

Plastic debris becomes currently a ubiquitous environmental pollutant and is susceptible to contamination by many other pollutants, including aqueous metals and organic matter. This review summarizes the effects of environmental factors on the properties and sorption behavior of microplastics, presents a further discussion on the fate of microplastics adsorption on contaminants, and critically discusses the mechanism of sorption behaviors between micro/nanoplastics and normal contaminants. Previous references indicated that the hydrophobicity and particle sizes of microplastics were the dominant influence factors for virgin plastic debris adsorption, whereas for aged microplastics, hydrogen bonding, hydrophilicity and increasing specific surface ratio affected the adsorption behavior. The effects of pH and salinity always influence the sorption conditions by changing the charge state of microplastics and contaminants and causing competing adsorption. In addition, the existence of microplastics affects biotoxicity, increases the dissolved organic matter in the environment, and influences carbon cycling. The knowledge is fundamental to the assessment of potential risks posed by microplastics to organisms from human beings to the entire environment.

Nano/microplastics in water and wastewater treatment processes - Origin, impact and potential solutions

The presence of nano and microplastics in water has increasingly become a major environmental challenge. A key challenge in their detection resides in the relatively inadequate analytical techniques available preventing deep understanding of the fate of nano/microplastics in water. The occurrence of nano/microplastics in water and wastewater treatment plants poses a concern for the quality of the treated water. Due to their broad but small size and diverse chemical natures, nano/microplastics may travel easily along water and wastewater treatment processes infiltrating remediation processes at various levels, representing operational and process stability challenges. This review aims at presenting the current understanding of the fate and impact of nano/microplastics through water and wastewater treatment plants. The formation and fragmentation mechanisms, physical-chemical properties and occurrence of nano/microplastics in water are correlated to the interactions of nano/microplastics with water and wastewater treatment plant processes and potential solutions to limit these interactions are comprehensively reviewed. This critical analysis offers new strategies to limit the number of nano/microplastics in water and wastewater to keep water quality up to the required standards and reduce threats on our ecosystems.

Quantification of the combined toxic effect of polychlorinated biphenyls and nano-sized polystyrene on Daphnia magna

It has been reported that nanoplastics (NP) could cause serious toxicity and accumulative effects on aquatic organisms as well as interact with organic pollutants and influence potential hazards when exposed to biota. The current study aimed to quantitatively investigate the combined acute toxic effect of polychlorinated biphenyls (PCBs) and nano-sized polystyrene (PS) plastic on aquatic organisms based on analyte speciation. First, the combined acute toxicity of PCB-18 and 100 nm PS to Daphnia magna (D. magna) in water was evaluated. Then, speciation analysis of the exposure system was conducted by measuring the sorption coefficients (logK_NP) of PCBs to nano-sized PS (ranging from 5.28 to 6.56), which demonstrated the PS could substantially decrease the free concentrations of PCBs. The results showed that a low concentration of the PS could decrease the toxicity to D. magna., which might be originated from the decreased free concentration of PCB-18. However, when the PS concentration was high enough, an opposite effect was observed because the PS dominated the lethality instead of PCB-18. The current study is helpful to clarify the PCB occurrence in ecosystems and provide an in-depth understanding of the eco-toxicological effects of nanoscale plastics.

Comparisons of analytical chemistry and biological activities of extracts from North Pacific gyre plastics with UV-treated and untreated plastics using in vitro and in vivo models

Plastic debris is an emerging worldwide threat to marine biota. Marine species may face unique challenges in low-flow estuarine systems with a high abundance of "macro-sized" (>4.75 mm) plastic due to the leaching of constituents and adsorbed contaminants. To simulate this leaching process, plastic samples recovered from the North Pacific Gyre along with corresponding UV-irradiated virgin plastic and non-irradiated virgin plastic counterparts were incubated in saltwater for 30 days at ambient temperatures ranging from 17 to 25 °C. Following solid-phase extraction, water samples were fractionated with sequential methanol elution from 10 to 100% and evaluated using in vitro assays assessing estrogen receptor (ER) and aryl hydrocarbon receptor (AhR) activities. In vivo responses (vitellogenin [vtg] and cytochrome p450 1A [cyp1a] mRNA) were measured following 5-day exposures in Japanese medaka (Oryzias latipes) larvae (3 days post hatch). Estrogenic plasticizers, co-planar PCBs and PAHs were quantified in the extracts using targeted GC-MS/MS and UPLC-MS/MS. In vitro estrogenicity showed highest activity in the 70% methanol fraction for all plastic leachate exposures. Whole extract in vitro estradiol equivalent (EEQ) values were 4.34 ± 2.65, 8.79 ± 2.09 and 13.78 ± 3.64 ng/L, for virgin plastic, UV-irradiated virgin plastic and North Pacific Gyre-recovered plastic, respectively (mean ± SD). Significant vtg induction was observed in medaka larvae exposed to leachate extracts from North Pacific Gyre-recovered plastic and UV-irradiated virgin plastic (9.9-fold, p = 0.039 and 10.1-fold, p = 0.042, respectively). Chemically-determined EEQ values were also localized in the 70% methanol fraction. Whole leachate extract chemical EEQ values were 0.33 ± 0.07, 1.64 ± 0.62 and 11.4 ± 2.13 ng/L, for virgin plastic, UV-irradiated virgin plastic and North Pacific Gyre-recovered plastic, respectively. In-vitro AhR activity was highest in the 70% methanol elution with greater activity in North Pacific Gyre-recovered plastic than in virgin plastic and UV-irradiated virgin plastic (toxic equivalency [TEQ] = 1.06 ± 0.54, 0.38 ± 0.07 and 0.71 ± 0.47 ng/L, respectively). CYP1A mRNA was significantly induced in larval medaka exposed to North Pacific Gyre-recovered plastic leachates (17.8-fold, p = 0.02) while exposure to virgin plastic and UV-irradiated virgin plastic leachates caused no significant change. Chemically-determined TEQ analysis for AhR indicated highest activity in the 90% methanol fraction for all leachates, with whole extract in vitro TEQs being 1.47 ± 0.87, 0.03 ± 0.05 and 0.42 ± 0.38 ng/L for North Pacific Gyre-recovered plastic, virgin plastic and UV-irradiated virgin plastic, respectively. These results indicate that weathering and UV radiation release estrogenic plasticizers and demonstrate the ability for plastics to transport adsorbed persistent organic pollutants at eco-toxicologically relevant concentrations.

Characterization, source, and retention of microplastic in sandy beaches and mangrove wetlands of the Qinzhou Bay, China

Severe microplastic pollution from anthropogenic activities in coastal zones presents an imminent risk to marine ecosystems. In this study, abundant microplastics (15-12,852 items kg^-1) with sizes ranging between 0.16 and 5.0 mm were extracted from 17 sediment samples collected in sandy beaches and mangrove wetlands of the Qinzhou Bay, Guangxi Province, Southwest China. Three types of microplastics (i.e. polystyrene, polypropylene, and polyethylene) were identified with Fourier transform infrared (FTIR) spectroscopy analysis. These detected microplastics were characterized by different colors (white, transparent, yellow, green, red, and blue) and shapes (fragment, fiber, and sphere). Microplastics were concentrated on supratidal beaches and wetlands outside of mangrove, and less abundant on intertidal beaches and inside of mangrove wetlands. Meanwhile, high microplastic concentrations were observed near mollusk farms. The spatial distribution and chemical speciation indicated that microplastics were derived from disintegration of large plastic debris (e.g., Styrofoam buoys used to support mollusk rafts) abandoned by aquaculture industry. Further, coastal vegetation (e.g. mangrove) could trap microplastic particles.

The impact of nanoplastics on marine dissolved organic matter assembly

The environmental impact of nanoplastics (NPs) released into natural aquatic surroundings is an increasing concern. NPs are widely generated from our daily waste disposal and eventually reach the ocean, wherein consequent influences on aquatic environments remain unclear. In this regard, there are few studies investigating NP-related ecological impacts. Comprising one of Earth's major carbon pools, marine dissolved organic matter (DOM) serves an essential role in global carbon dynamics. The spontaneous assembly of DOM into particulate organic matter (POM) plays important roles in the marine carbon cycle, and is involved in hemostasis of various ecological communities. Here, we report that 10 ppb NPs (polystyrene/polymethyl methacrylate, 25 nm) appeared in a water column accelerate the kinetic assembly rate of DOM-POM transition. NPs with various characteristics show similar influences on DOM assembly, and seawater samples collected from disparate sites were used to further confirm this unanticipated phenomenon. In this study, we demonstrated that hydrophobic interactions contribute to the facilitation of NP-DOM aggregations. Our results illustrate that NPs alter DOM-POM assembly, which may potentiate unanticipated perturbation to the largest marine carbon pool. Such effects would warrant increased vigilance on current practices of plastic usage and disposal.

Neurobehavioral assessment of rats exposed to pristine polystyrene nanoplastics upon oral exposure

The increasing use of plastics has raised concerns about pollution of freshwater by these polymeric materials. Knowledge about their potential effects on environmental and public health is limited. Recent publications have suggested that the degradation of plastics will result in the release of nano-sized plastic particles to the environment. Therefore, it is of utmost importance to gain knowledge about whether and how nanoplastics affect living organisms. The present study aimed to analyse potential neurobehavioral effects of polystyrene nanoparticles (PS-NPs) after long-term exposure on rat. Potential effects of PS-NPs were investigated using four test dosages (1, 3, 6, and 10 mg PS-NPs/kg of body weight/day) administrated orally with adult Wistar male rats for five weeks. Neurobehavioral tests were chosen to assess a variety of behavioral domains. Particle diameters in test suspensions were determined through dynamic light scattering and showed an average hydrodynamic diameter of approximately 38.92 nm. No statistically significant behavioral effects were observed in all tests performed (p > 0.05). In the elevated plus maze, PS-NPs-exposed rats showed greater number of entries into open arms compared to controls. Also, PS-NPs had no significant influence on body weight of animals. Taking into account the subtle and transient nature of neurobehavioral consequences, however, these results underline the possibility of even pristine plastic nanoparticles to induce behavioral alteration in the rest of the food web, including for marine biota and humans. Indeed even though studied neurobehavioral effects in our study was not statistically significant, the observed subtle effects may be clinically considerable.

Assessment of chemicals released in the marine environment by dielectric elastomers useful as active elements in wave energy harvesters

A series of elastomers, either natural or synthetic (some of them commercial, while others prepared in the laboratory), suitable for use as active elements in devices for wave energy harvesting, were evaluated concerning their behavior and effects on the marine environment. In this aim, the elastomer films, initially evaluated regarding their aspect, structure, surface wettability, and tolerance of microorganisms growth, were immersed in synthetic seawater (SSW) within six months for assessing compounds released. There were analyzed the changes occurred both in the elastomers and salt water in which they were immersed. For this, water samples taken at set time intervals were analyzed by using a sequence of sensitive spectral techniques: UV-vis, IR, and in relevant cases ¹H NMR and electrospray ionization mass spectrometry (ESI-MS), able to detect and identify organic compounds, while after six months, they were also investigated from the point of view of aspect, presence of metal traces, pH, and biological activity. The changes in aspect, structure and morphology of the dielectric films at the end of the dipping period were also evaluated by visual inspection, IR spectroscopy by using spectral subtraction method, and SEM-EDX technique.

Brain damage and behavioural disorders in fish induced by plastic nanoparticles delivered through the food chain

The tremendous increases in production of plastic materials has led to an accumulation of plastic pollution worldwide. Many studies have addressed the physical effects of large-sized plastics on organisms, whereas few have focused on plastic nanoparticles, despite their distinct chemical, physical and mechanical properties. Hence our understanding of their effects on ecosystem function, behaviour and metabolism of organisms remains elusive. Here we demonstrate that plastic nanoparticles reduce survival of aquatic zooplankton and penetrate the blood-to-brain barrier in fish and cause behavioural disorders. Hence, for the first time, we uncover direct interactions between plastic nanoparticles and brain tissue, which is the likely mechanism behind the observed behavioural disorders in the top consumer. In a broader perspective, our findings demonstrate that plastic nanoparticles are transferred up through a food chain, enter the brain of the top consumer and affect its behaviour, thereby severely disrupting the function of natural ecosystems.