Plastics everywhere: first evidence of polystyrene fragments inside the common Antarctic collembolan Cryptopygus antarcticus

Microplastics in bulk atmospheric deposition along the coastal region of Victoria Land, Antarctica

The increasing global concern over microplastic pollution has driven a surge in research efforts aimed at detecting microplastics across various ecosystems. Airborne microplastics (MPs) have been identified in remote environments worldwide, including Antarctica. However, data on bulk atmospheric deposition remain scarce. From January to December 2020, atmospheric deposition was directly collected using passive samplers placed in eight sites across Victoria Land. Using Raman Microspectroscopy, MPs were identified in six out of the seven samples collected (one sample was lost due to the extreme weather conditions). The average daily MP deposition for Victoria Land was 1.7 ± 1.1 MPs m-2 d-1, with values ranging from 0.76 to 3.44 MPs m-2 d-1. The majority (53 %) of MPs found in the atmospheric deposition were in the size class of 5-10 μm, and the main shape of MPs was fragments (95 %). The predominant plastic type was polypropylene (31 %), followed by polyethylene (19 %) and polycarbonate (12 %). Polystyrene, polyester, styrene and polyethylene terephthalate each accounted for ~6 %. Microplastics identified in the coastal sites may have local origins, potentially associated with scientific activities at research stations. Conversely, a backward trajectories analysis suggested a potential contribution of atmospheric transport to microplastic deposition at Larsen Glacier and Tourmaline Plateau, the two most remote sites of the study area, where the highest MP concentrations were detected. Our findings present the first evidence of microplastics in the Antarctic atmospheric deposition directly collected via passive samplers, highlighting the need for continued monitoring and research to assess the environmental impact of MPs, particularly in sensitive and remote ecosystems like Antarctica.

Comparative study of polystyrene microplastic transport behavior in three different filter media: Quartz sand, zeolite, and anthracite

Microplastics (MPs) are emerging contaminants that are attracting increasing interest from researchers, and the safety of drinking water is greatly affected by their transportation during filtration. Polystyrene (PS) was selected as a representative MPs, and three filter media (quartz sand, zeolite, and anthracite) commonly found in water plants were used. The retention patterns of PS-MPs by various filter media under various background water quality conditions were methodically investigated with the aid of DLVO theory and colloidal filtration theory. The results show that the different structures and elemental compositions of the three filter media cause them to exhibit different surface roughnesses and surface potentials. A greater surface roughness of the filter media can provide more deposition sites for PS-MPs, and the greater surface roughness of zeolite and anthracite significantly enhances their ability to inhibit the migration of PS-MPs compared with that of quartz sand. However, surface roughness is not the only factor affecting the migration of MPs. The lower absolute value of the surface potential of anthracite causes the DLVO energy between it and PS-MPs to be significantly lower than that between zeolite and PS-MPs, which results in stronger retention of PS-MPs by anthracite, which has a lower surface roughness, than zeolite, which has a higher surface roughness. The transport of PS-MPs in the medium is affected by the combination of the surface roughness of the filter media and the DLVO energy. Under the same operating conditions, the retention efficiencies of the three filter materials for PS-MPs followed the order of quartz sand < zeolite < anthracite. Additionally, the conditions of the solution markedly influenced the transport ability of PS-MPs within the simulated filter column. The transport PS-MPs in the simulated filter column decreased with increasing solution ionic strength and cation valence. Naturally, dissolved organic matter promoted the transfer of PS-MPs in the filter layer, and humic acid had a much stronger facilitating impact than fulvic acid. The study findings might offer helpful insight for improving the ability of filter units ability to retain MPs.

Trends in Antarctic soil fungal research in the context of environmental changes

Antarctic soils represent one of the most pristine environments on Earth, where highly adapted and often endemic microbial species withstand multiple extremes. Specifically, fungal diversity is extremely low in Antarctic soils and species distribution and diversity are still not fully characterized in the continent. Despite the unique features of this environment and the international interest in its preservation, several factors pose severe threats to the conservation of inhabiting ecosystems. In this light, we aimed to provide an overview of the effects on fungal communities of the main changes endangering the soils of the continent. Among these, the increasing human presence, both for touristic and scientific purposes, has led to increased use of fuels for transport and energy supply, which has been linked to an increase in unintentional environmental contamination. It has been reported that several fungal species have evolved cellular processes in response to these soil contamination episodes, which may be exploited for restoring contaminated areas at low temperatures. Additionally, the effects of climate change are another significant threat to Antarctic ecosystems, with the expected merging of previously isolated ecosystems and their homogenization. A possible reduction of biodiversity due to the disappearance of well-adapted, often endemic species, as well as an increase of biodiversity, due to the spreading of non-native, more competitive species have been suggested. Despite some studies describing the specialization of fungal communities and their correlation with environmental parameters, our comprehension of how soil communities may respond to these changes remains limited. The majority of studies attempting to precisely define the effects of climate change, including in situ and laboratory simulations, have mainly focused on the bacterial components of these soils, and further studies are necessary, including the other biotic components.

Nanoplastics and Neurodegeneration in ALS

Plastic production, which exceeds one million tons per year, is of global concern. The constituent low-density polymers enable spread over large distances and micro/nano particles (MNPLs) induce organ toxicity via digestion, inhalation, and skin contact. Particles have been documented in all human tissues including breast milk. MNPLs, especially weathered particles, can breach the blood-brain barrier, inducing neurotoxicity. This has been documented in non-human species, and in human-induced pluripotent stem cell lines. Within the brain, MNPLs initiate an inflammatory response with pro-inflammatory cytokine production, oxidative stress with generation of reactive oxygen species, and mitochondrial dysfunction. Glutamate and GABA neurotransmitter dysfunction also ensues with alteration of excitatory/inhibitory balance in favor of reduced inhibition and resultant neuro-excitation. Inflammation and cortical hyperexcitability are key abnormalities involved in the pathogenic cascade of amyotrophic lateral sclerosis (ALS) and are intricately related to the mislocalization and aggregation of TDP-43, a hallmark of ALS. Water and many foods contain MNPLs and in humans, ingestion is the main form of exposure. Digestion of plastics within the gut can alter their properties, rendering them more toxic, and they cause gut microbiome dysbiosis and a dysfunctional gut-brain axis. This is recognized as a trigger and/or aggravating factor for ALS. ALS is associated with a long (years or decades) preclinical period and neonates and infants are exposed to MNPLs through breast milk, milk substitutes, and toys. This endangers a time of intense neurogenesis and establishment of neuronal circuitry, setting the stage for development of neurodegeneration in later life. MNPL neurotoxicity should be considered as a yet unrecognized risk factor for ALS and related diseases.

Assessing the current state of plastic pollution research in Antarctica: Knowledge gaps and recommendations

Antarctica stands as one of the most isolated and pristine regions on our planet. Regardless, recent studies have evidenced the presence of plastic pollution in Antarctic environments and biota. While these findings are alarming and put into perspective the reach of plastic pollution, it is necessary to assess the current knowledge of plastic pollution in Antarctica. In the present review, an updated literature review of plastic pollution in multiple Antarctic environmental compartments and biota was conducted. Studies were cataloged based on environmental compartments (e.g., sediments, seawater, soil, atmosphere) and biota from different ecological niches. A detailed analysis of the main findings, as well as the flaws and shortcomings across studies, was conducted. In general terms, several studies have shown a lack of adequate sampling and analytical procedures for plastic research (particularly in the case of microplastics) and standard procedures; thus, compromising the reliability of the data reported and comparability across studies. Aiming to guide future studies and highlight research needs, a list of knowledge gaps and recommendations were provided based on the analysis and discussion of the literature and following standardized procedures.

Short-term impacts of polyethylene and polyacrylonitrile microplastics on soil physicochemical properties and microbial activity of a marine terrace environment in maritime Antarctica

Evidence of microplastic (MP) pollution in Antarctic terrestrial environments reinforces concerns about its potential impacts on soil, which plays a major role in ecological processes at ice-free areas. We investigated the effects of two common MP types on soil physicochemical properties and microbial responses of a marine terrace from Fildes Peninsula (King George Island, Antarctica). Soils were treated with polyethylene (PE) fragments and polyacrylonitrile (PAN) fibers at environmentally relevant doses (from 0.001% to 1% w w-1), in addition to a control treatment (0% w w-1), for 22 days in a pot incubation experiment under natural field conditions. The short-term impacts of MPs on soil physical, chemical and microbial attributes seem interrelated and were affected by both MP dose and type. The highest PAN fiber dose (0.1%) increased macro and total porosity, but decreased soil bulk density compared to control, whereas PE fragments treatments did not affect soil porosity. Soil respiration increased with increasing doses of PAN fibers reflecting impacts on physical properties. Both types of MPs increased microbial activity (fluorescein diacetate hydrolysis), decreased the cation exchange capacity but, especially PE fragments, increased Na+ saturation. The highest dose of PAN fibers and PE fragments increased total nitrogen and total organic carbon, respectively, and both decreased the soil pH. We discussed potential causes for our findings in this initial assessment and addressed the need for further research considering the complexity of environmental factors to better understand the cumulative impacts of MP pollution in Antarctic soil environments.

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.

Low numbers of large microplastics on environmentally-protected Antarctic beaches reveals no widespread contamination: insights into beach sedimentary dynamics

Microplastics are ubiquitous contaminants of marine ecosystems around the world and Antarctica is no exception. Microplastics can be influenced by sedimentary dynamics mainly on coastal areas where they are more abundant in Antarctica. This study evaluated microplastic contamination in beach environments from two Antarctic Specially Protected Areas, aiming to identify relationships between microplastic numbers and sedimentological parameters on beach sediments. Low numbers of microplastics were found (> 0.5 mm; fibers excluded) - one particle per sample in 4 of 15 samples analyzed - and there is no evidence of widespread contamination. Sedimentological parameters reveal differences between sampled environments, but low numbers of microplastics impaired statistical comparison. All sediment samples are coarse, denoting highenergy depositional environments that are likely little susceptible to microplastic accumulation. Microplastic contamination in the Antarctic coastal ecosystem is heterogeneous, and their detailed characterization assisted by a systematization of methods can improve the understanding of microplastics distribution patterns in the cold coastal ecosystem.

The forgotten impacts of plastic contamination on terrestrial micro- and mesofauna: A call for research

Microplastics (MP) and nanoplastics (NP) contamination of the terrestrial environment is a growing concern worldwide and is thought to impact soil biota, particularly the micro and mesofauna community, by various processes that may contribute to global change in terrestrial systems. Soils act as a long-term sink for MP, accumulating these contaminants and increasing their adverse impacts on soil ecosystems. Consequently, the whole terrestrial ecosystem is impacted by microplastic pollution, which also threatens human health by their potential transfer to the soil food web. In general, the ingestion of MP in different concentrations by soil micro and mesofauna can adversely affect their development and reproduction, impacting terrestrial ecosystems. MP in soil moves horizontally and vertically because of the movement of soil organisms and the disturbance caused by plants. However, the effects of MP on terrestrial micro-and mesofauna are largely overlooked. Here, we give the most recent information on the forgotten impacts of MP contamination of soil on microfauna and mesofauna communities (protists, tardigrades, soil rotifers, nematodes, collembola and mites). More than 50 studies focused on the impact of MP on these organisms between 1990 and 2022 have been reviewed. In general, plastic pollution does not directly affect the survival of organisms, except under co-contaminated plastics that can increase adverse effects (e.g. tire-tread particles on springtails). Besides, they can have adverse effects at oxidative stress and reduced reproduction (protists, nematodes, potworms, springtails or mites). It was observed that micro and mesofauna could act as passive plastic transporters, as shown for springtails or mites. Finally, this review discusses how soil micro- and mesofauna play a key role in facilitating the (bio-)degradation and movement of MP and NP through soil systems and, therefore, the potential transfer to soil depths. More research should be focused on plastic mixtures, community level and long-term experiments.

The genus Artemia, the nanoplastics, the microplastics, and their toxic effects: a review

Plastic pollution is a threat to the marine environment, the destination of mismanaged plastic. Due to reduced size, microplastics and nanoplastics (MNPs) can interact with a wide range of organisms. Non-selective filter feeder zooplanktonic microcrustaceans are potential targets for MNP accumulation. Zooplankton is a key group for the food web, linking primary producers to secondary consumers. The genus Artemia has been widely used to investigate the effects of plastic particles on the biota. The present work critically reviewed the ecotoxicological studies about plastic particles and Artemia, pointing out methodological aspects and effects caused by MNPs, highlighting their importance and limitations, and suggesting directions for future research. We analyzed twenty-one parameters into four categories: characteristics of plastic particles, general particularities of brine shrimp, methodologies of the cultures, and toxicological parameters. The principal gaps in the area are the lack of methodological standardization regarding the physicochemical parameters of the particles, the biology of the animals, and culture conditions. Even though few studies performed realistic exposure scenarios, results indicate MNPs as potential harmful contaminants to microcrustaceans. The main effects reported were particle ingestion and accumulation followed by reduced brine shrimp survival/mobility. The present review poses Artemia as suitable animals for investigations concerning the risks of MNP exposure at the individual level and to the ecosystems, although protocol standardization is still needed.

The need for environmentally realistic studies on the health effects of terrestrial microplastics

Plastic pollution is now so widespread that microplastics are regularly detected in biological samples surveyed for their presence. Despite their pervasiveness, very little is known about the effects of microplastics on the health of terrestrial vertebrates. While emerging studies are showing that microplastics represent a potentially serious threat to animal health, data have been limited to in vivo studies on laboratory rodents that were force fed plastics. The extent to which these studies are representative of the conditions that animals and humans might actually experience in the real world is largely unknown. Here, we review 114 papers from the peer-reviewed literature in order to understand how the concentrations and types of microplastics being administered to rodents in lab studies compare to those found in terrestrial soils. From 73 in vivo lab studies, and 41 soil studies, we found that lab studies have heretofore fed rodents microplastics at concentrations that were hundreds of thousands of times greater than they would be exposed to in nature. Furthermore, health effects have been studied for only 20% of the microplastic polymers that are known to occur in soils. Plastic pollution is arguably one of the most pressing ecological and public health issues of our time, yet existing lab-based research on the health effects of terrestrial microplastics does not reflect the conditions that free-ranging vertebrates are actually experiencing. Going forward, performing more true-to-life research will be of the utmost importance to fully understand the impacts of microplastics and maintain the public's faith in the scientific process.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s43591-023-00059-1.

Evaluation of the Deterioration of Untreated Commercial Polystyrene by Psychrotrophic Antarctic Bacterium

Polystyrene (PS) and microplastic production pose persistent threats to the ecosystem. Even the pristine Antarctic, which is widely believed to be pollution-free, was also affected by the presence of microplastics. Therefore, it is important to comprehend the extent to which biological agents such as bacteria utilise PS microplastics as a carbon source. In this study, four soil bacteria from Greenwich Island, Antarctica, were isolated. A preliminary screening of the isolates for PS microplastics utilisation in the Bushnell Haas broth was conducted with the shake-flask method. The isolate AYDL1 identified as Brevundimonas sp. was found to be the most efficient in utilising PS microplastics. An assay on PS microplastics utilisation showed that the strain AYDL1 tolerated PS microplastics well under prolonged exposure with a weight loss percentage of 19.3% after the first interval (10 days of incubation). Infrared spectroscopy showed that the bacteria altered the chemical structure of PS while a deformation of the surface morphology of PS microplastics was observed via scanning electron microscopy after being incubated for 40 days. The obtained results may essentially indicate the utilisation of liable polymer additives or "leachates" and thus, validate the mechanistic approach for a typical initiation process of PS microplastics biodeterioration by the bacteria (AYDL1)-the biotic process.

Impact of anthropogenic contamination on glacier surface biota

Glaciers are ecosystems and they host active biological communities. Despite their remoteness, glaciers act as cold condensers where high precipitation rates and cold temperatures favor the deposition of pollutants. These contaminants include a broad range of substances, including legacy pollutants, but also compounds still largely used. Some of these compounds are monitored in the environment and their effects on the ecosystems are known, in contrast others can be defined as emerging pollutants since their presence and their impact on the environment are still poorly understood (e.g. microplastics, radionuclides). This review aim to provide an overview of the studies that have investigated the effects of pollutants on the supraglacial ecosystem so far. Despite the distribution of the pollutants in glacier environments has been discussed in several studies, no review paper has summarized the current knowledge on the effects of these substances on the ecological communities living in glacier ecosystems.

Microbial engineering strategies for synthetic microplastics clean up: A review on recent approaches

Microplastics are the small fragments of the plastic molecules which find their applications in various routine products such as beauty products. Later, it was realized that it has several toxic effects on marine and terrestrial organisms. This review is an approach in understanding the microplastics, their origin, dispersal in the aquatic system, their biodegradation and factors affecting biodegradation. In addition, the paper discusses the major engineering approaches applied in microbial biotechnology. Specifically, it reviews microbial genetic engineering, such as PET-ase engineering, MHET-ase engineering, and immobilization approaches. Moreover, the major challenges associated with the plastic removal are presented by evaluating the recent reports available.

Occurrence and distribution of legacy and emerging pollutants including plastic debris in Antarctica: Sources, distribution and impact on marine biodiversity

Since the first explorers reached Antarctica, their activities have quickly impacted both land and sea and thus, together with the long-range transport, hazardous chemicals began to accumulate. It is commonly recognized that anthropogenic pollution in Antarctica can originate from either global or local sources. Heavy metals, organohalogenated compounds, hydrocarbons, and (more recently) plastic, have been found in Antarctic biota, soil sediments, seawater, air, snow and sea-ice. Studies in such remote areas are challenging and expensive, and the complexity of potential interactions occurring in such extreme climate conditions (i.e., low temperature) makes any accurate prediction on potential impacts difficult. The present review aims to summarize the current state of knowledge on occurrence and distribution of legacy and emerging pollutants in Antarctica, such as plastic, from either global or local sources. Future actions to monitor and mitigate any potential impact on Antarctic biodiversity are discussed.

Textile microfibers in wild Antarctic whelk Neobuccinum eatoni (Smith, 1875) from Terra Nova Bay (Ross Sea, Antarctica)

Antarctica has been affected directly and indirectly by human pressure for more than two centuries and recently plastic pollution has been recognized as a further potential threat for its unique biodiversity. Global long-range transport as well as local input from anthropogenic activities are potential sources of plastic pollution in both terrestrial and marine Antarctic territories. The present study evaluated the presence of microplastics in specimens of the Antarctic whelk Neobuccinum eatoni, a key species in benthic communities of the Ross Sea, one of the largest marine protected areas worldwide. To this aim, a thermo-oxidative extraction method was applied for microplastic isolation and quantification, and polymer identification was performed by manual μ-FTIR spectroscopy. Textile (semi-)synthetic or composite microfibers (length range: 0.8-5.7 mm) were found in 27.3% of whelk specimens, suggesting a low risk of bioaccumulation along Antarctic benthic food webs in the Ross Sea. Their polymer composition (of polyethylene terephthalate and cellulose-polyamide composites) matched those of outdoor technical clothing in use by the personnel of the Italian "Mario Zucchelli" station near Terra Nova Bay in the Ross Sea. Such findings indicate that sewage from base stations may act as potential local sources of textile microplastic fibers in this remote environment. More in-depth monitoring studies aiming at defining the extent of microplastic contamination related to such sources in Antarctica are encouraged.

Anthropogenic microparticles in the emerald rockcod Trematomus bernacchii (Nototheniidae) from the Antarctic

Anthropogenic microparticles (AMs) were found for the first time in specimens of Trematomus bernacchii collected in 1998 in the Ross Sea (Antarctica) and stored in the Antarctic Environmental Specimen Bank. Most of the identified AMs were fibers of natural and synthetic origin. The natural AMs were cellulosic, the synthetic ones were polyester, polypropylene, polypropylene/polyester, and cellulose acetate. The presence of dyes in the natural AMs indicates their anthropogenic origin. Five industrial dyes were identified by Raman spectroscopy with Indigo occurring in most of them (55%). Our research not only adds further data to the ongoing knowledge of pollution levels in the Antarctic ecosystem, it provides an interesting snapshot of the past, highlighting that microplastics and anthropogenic fiber pollution had already entered the Antarctic marine food web at the end of the '90 s. These findings therefore establish the foundations for understand the changes in marine litter pollution over time.

Behavioural, physiological and molecular responses of the Antarctic fairy shrimp Branchinecta gaini (Daday, 1910) to polystyrene nanoplastics

Plastic pollution represents an emerging environmental issue in terrestrial Antarctica, especially in the Antarctic Peninsula and Maritime Antarctica, which have been recently recognized as hot spots for plastic litter. In these regions, freshwater (FW) environments such as lakes host isolated ecosystems and species that can be severely affected by increasing environmental and anthropogenic stressors, which include plastics that are still overlooked. In this study, we investigated for the first time the impact of nanoplastics on adults of the fairy shrimp Branchinecta gaini (Order Anostraca) populating Antarctic FW ecosystems, using surface charged polystyrene nanoparticles (PS NPs) as a proxy. Short-term acute toxicity (48 h) was investigated by exposing adults to carboxyl (-COOH, 60 nm) and amino-modified (-NH₂, 50 nm) PS NPs at 1 and 5 μg mL^-1. Biodisposition of PS NPs and lethal and sub-lethal effects (i.e., swimming, moulting, histology, gene expression) were assessed. Behaviour of PS NPs in Antarctic FW media was monitored through 48 h of exposure showing that both PS NPs kept their nanoscale size in the Antarctic FW media. Survival of fairy shrimp adults over short-term exposure was not affected, on the other hand an increase in moulting rate and alterations in the gut epithelium were observed upon exposure to both PS NPs. Significant alterations at the behavioural (ventilation rate) and molecular (up-regulation of Hsp70mit, Hsp83, Sod, P450) levels were related to PS NP surface charge and associated with PS-NH₂ exposure only. Nanoplastics could represent a threat for Antarctic FW biodiversity and the Antarctic fairy shrimp could be a valuable model for assessing their impact on such remote and pristine aquatic ecosystems.

Distribution, sources, migration, influence and analytical methods of microplastics in soil ecosystems

Microplastics are ubiquitous in soil ecosystems all over the world through source and migration. It is even estimated that the content of microplastics in terrestrial ecosystems exceeds the number of microplastics entering sea ecosystems. However, compared with the research on microplastics in marine ecosystems, the research and discussion on microplastics in soil ecosystems are still less. Transportation, film mulching and sewage sludge are three main sources of soil microplastics. The abundance, polymer type, size and shape of the microplastics are related to the source and they help to clarify the source. The characteristics of microplastics, farming measures, soil animal activities and other factors promote the migration of microplastics, which bring new challenges to the soil ecosystems and humans. This article summarizes the latest research findings on the effects of soil microplasticity on soil properties, plants, animals and microorganisms. The analysis methods of microplastics in soil can refer to the analysis methods of microplastics of aquatic sediments, because soil and aquatic sediments are similar, both of which are complex solid substrates. At present, the development of analytical methods is limited due to the complex matrix of soil and the small volume of microplastics, which requires continuous development and innovation. Through the summary and analysis of related articles, this article reviews the distribution, sources, migration, influence and analysis methods of soil microplastics. This article also critically analyzes the deficiencies in the studies of microplastics in the soil ecosystems, and made some suggestions for future work. The microplastics in soil ecosystems need further research and summary, which will help people further understand the potential hazards of microplastics.

Stranded pellets in Fildes Peninsula (King George Island, Antarctica): New evidence of Southern Ocean connectivity

Plastic and microplastic debris is transported by ocean currents over long distances, reaching remote areas, far from its original source. In Polar Regions, microplastics (MPs) can come from local activities or be transported from lower latitudes, with the former being the likely and major source. Although historically Antarctica was considered isolated from the global ocean, there is recent evidence of materials and organisms being transported in and out of the Southern Ocean, despite its multi-front structure. During the austral summer of 2019, beach surveys were conducted on the NW coast of the Fildes Peninsula (King George Island). The beach was characterised, and the first 2 cm of sediment from 5 quadrants (50 × 50 cm) along 100 m of the highest strandline were collected. Large microplastics (LMPs) and mesoplastics (MesoPs) were isolated, counted, measured, weighed and classified by shape. Polymer composition was analysed by FTIR and ageing estimated by Carbonyl Index. We found 293 items of LMPs (188 items) and MesoPs (105 items), with a total average density (±SD) of 234.4 ± 166 items m^-2. Foams (130.4 ± 76.3), fragments (58.4 ± 56.0) and pellets (44.0 ± 50.5) were the most abundant shapes. The main polymers found were polystyrene, polypropylene, and polyethylene. We found pellets among the MesoPs, being the first record for beaches in Antarctica. The presence of these primary MPs south of 62°S not only alerts about their possible direct consequences on Antarctic ecosystems, but also gives empirical evidence for the passive entry of plastic debris from lower latitudes through cross-frontal exchanges, providing new evidence of a global connectivity of the Southern Ocean. Despite increasing research, knowledge of plastics dynamics and their impact in the Southern Ocean and Antarctica is still limited but certainly necessary.

Distribution characteristics of microplastics in surface and subsurface Antarctic seawater

Microplastics have attracted worldwide attention due to their potential threat to the marine ecosystem, with such pollutants even detected in the polar seas. Although in-depth research on microplastics has increased in recent years, studies in Antarctic waters remain relatively scarce compared with coastal waters and open oceans. In this study, microplastics in surface and subsurface Antarctic waters were investigated. The average microplastic abundance in the surface water was 0.10 ± 0.14 items/m³, with highest abundance in the Ross Sea, and the average microplastic abundance in the subsurface water was 1.66 ± 1.20 items/m³, with highest abundance in the Dumont d'Urville Sea. Polyester was the main microplastic in the surface waters (87.3%), while polypropylene (33.1%), polyester (28.7%), and polyethylene (22.8%) were the dominant microplastics in the subsurface waters. Results indicate that microplastic pollution in Antarctic waters may come from the Antarctic continent as well as southward transport from the ocean at mid- and low latitudes.

Ecotoxicological effects of micro- and nanoplastics on terrestrial food web from plants to human beings

Micro- and nanoplastics (MNPs) are present in almost all environmental compartments. Terrestrial soils are major environmental reservoirs for MNPs, but the ecotoxicological effects of MNPs on terrestrial biota remain relatively understudied. In this review, we collated findings of previous research on the uptake and impact of MNPs in terrestrial organisms, including flora, fauna, and human beings. Terrestrial plants can take up MNPs via the roots or leaves and translocate them to other parts. MNPs have been detected in the gastrointestinal tracts or feces of many terrestrial animals, including some high trophic-level predators, indicating the incidence of direct ingestion or trophic transfer of MNPs. The presence of MNPs in food items and human feces combines to verify human intake of MNPs via the dietary pathway. Exposure to MNPs can cause diverse effects on terrestrial organisms, including alterations in growth performance, oxidative stress, metabolic disturbance, cytotoxicity, genotoxicity, and mortality. The biological internalization and impact of MNPs are influenced by the physicochemical properties of MNPs (e.g., particle size, polymer type, surface chemistry, and exposure concentrations) and the physiology of the species. MNPs can also affect the bioavailability of co-occurring intrinsic or extrinsic contaminants to terrestrial biota, but their specific role is under dispute. Finally, we underlined the current research gaps and proposed several priorities for future studies.

Macro- and Microplastics in the Antarctic Environment: Ongoing Assessment and Perspectives

The number of scientists and tourists visiting Antarctica is on the rise and, despite the management framework for environmental protection, some coastal areas, particularly in the Antarctic Peninsula region, are affected by plastic contamination. The few data available on the occurrence of microplastics (<5 mm) are difficult to compare, due to the different methodologies used in monitoring studies. However, indications are emerging to guide future research and to implement environmental protocols. In the surface and subsurface waters of the Southern Ocean, plastic debris >300 µm appears to be scarce and far less abundant than paint chips released from research vessels. Yet, near some coastal scientific stations, the fragmentation and degradation of larger plastic items, as well as microbeads and microfibers released into wastewater from personal care products and laundry, could potentially affect marine organisms. Some studies indicate that, through long-range atmospheric transport, plastic fibers produced on other continents can be deposited in Antarctica. Drifting plastic debris can also cross the Polar Front, with the potential to carry alien fouling organisms into the Southern Ocean. Sea ice dynamics appear to favor the uptake of microplastics by ice algae and Antarctic krill, the key species in the Antarctic marine food web. Euphausia superba apparently has the ability to fragment and expel ingested plastic particles at the nanoscale. However, most Antarctic organisms are endemic species, with unique ecophysiological adaptations to extreme environmental conditions and are likely highly sensitive to cumulative stresses caused by climate change, microplastics and other anthropogenic disturbances. Although there is limited evidence to date that micro- and nanoplastics have direct biological effects, our review aims at raising awareness of the problem and, in order to assess the real potential impact of microplastics in Antarctica, underlines the urgency to fill the methodological gaps for their detection in all environmental matrices, and to equip scientific stations and ships with adequate wastewater treatment plants to reduce the release of microfibers.

Impact of waste of COVID-19 protective equipment on the environment, animals and human health: a review

During the Corona Virus Disease 2019 (COVID-19) pandemic, protective equipment, such as masks, gloves and shields, has become mandatory to prevent person-to-person transmission of coronavirus. However, the excessive use and abandoned protective equipment is aggravating the world's growing plastic problem. Moreover, above protective equipment can eventually break down into microplastics and enter the environment. Here we review the threat of protective equipment associated plastic and microplastic wastes to environments, animals and human health, and reveal the protective equipment associated microplastic cycle. The major points are the following:1) COVID-19 protective equipment is the emerging source of plastic and microplastic wastes in the environment. 2) protective equipment associated plastic and microplastic wastes are polluting aquatic, terrestrial, and atmospheric environments. 3) Discarded protective equipment can harm animals by entrapment, entanglement and ingestion, and derived microplastics can also cause adverse implications on animals and human health. 4) We also provide several recommendations and future research priority for the sustainable environment. Therefore, much importance should be attached to potential protective equipment associated plastic and microplastic pollution to protect the environment, animals and humans.

The polymers and their additives in particulate plastics: What makes them hazardous to the fauna?

Due to the increasing concerns on global ecosystems and human health, the environmental risks posed by microplastics (MPs) and nanoplastics (NPs) have become an important topic of research. Their ecological impacts on various faunal species have been extensively researched and reviewed. However, the majority of those studies perceive these micro(nano)-plastics (MNPs) as a single entity rather than a collective term for a group of chemically distinct polymeric particulates. Each of the plastic polymers can possess unique physical and chemical behavior, which, in turn, can determine the possible environmental impacts. Furthermore, many studies explore the adsorption, absorption, and release of other environmental pollutants by MNPs. But only a handful of them explore the leaching of additives possessed by these polymers. Data on the environmental behavior and toxicity of individual additives associated with different polymer particulates are scarce. Knowledge about the leachability and ecotoxicity of the additives associated with environmental MNPs (unlike large plastic particles) remains limited. The ecological impacts of different MNPs together with their additives and the basis of their toxicity have not been explored yet. The present review systematically explores the potential implications of environmentally predominant polymers and their associated additives and discusses their physicochemical characteristics. The review ultimately aims to provide novel insights on what components precisely make MNPs hazardous to the fauna. The paper also discusses the major challenges proposed in the available literature along with recommendations for future research to throw light on possible solutions to overcome the hazards of MNPs.

Biofilm on microplastics in aqueous environment: Physicochemical properties and environmental implications

The excellent properties of plastics make them widely used all over the world. However, when plastics enter the environmental medium, microplastics will inevitably be produced due to physical, chemical and biological factors. Studies have shown that microplastics have been detected in terrestrial, aquatic and atmospheric environments. In addition, the presence of microplastics will provide a new artificial adhesion substrate for biofilms. It has been proved that the formation of biofilms could significantly change some properties of microplastics. Some studies have found that microplastics attached with biofilms have higher environmental risks and eco-toxicity. Therefore, considering the widespread existence of microplastics and the ecological risks of microplastic biofilms, the physical and chemical properties of biofilms on microplastics and their impact on microplastics in aqueous environment are worth reviewing. In this paper, we comprehensively reviewed representative studies in this area. Firstly, this study reviews that the existence of biofilms could change the transport and deposition of microplastics. Subsequently, the presence of biofilms would enhance the ability of microplastics to accumulate pollutant, such as persistent organic pollutants, heavy metals and antibiotics. Moreover, the effect of biofilms on microplastics enrichment of harmful microorganisms is summarized. Finally, some future research needs and strategies are proposed to better understand the problem of biofilms on microplastics.

Soil Invertebrates Generate Microplastics From Polystyrene Foam Debris

To fully understand microplastics' impact on soil ecosystems, one must recognize soil organisms as not just passively enduring their negative effects, but potentially contributing to microplastics' formation, distribution, and dynamics in soil. We investigated the ability of four soil invertebrates, the cricket Acheta domesticus L. (Orthoptera: Gryllidae), the isopod Oniscus asellus L. (Isopoda: Oniscidae), larvae of the beetle Zophobas morio Fabricius (Coleoptera: Tenebrionidae), and the snail Cornu aspersum Müller (Stylommatophora: Helicidae) to fragment macroscopic pieces of weathered or pristine polystyrene (PS) foam. We placed invertebrates into arenas with single PS foam pieces for 24 h, then collected and assessed the microplastic content of each invertebrate's fecal material, its cadaver, and the sand substrate of its arena via hydrogen peroxide digestion, filtration, and fluorescent staining. All taxa excreted PS particles, though snails only to a tiny extent. Beetle larvae produced significantly more microplastics than snails, and crickets and isopods fragmented the weathered PS foam pieces more than the pristine pieces, which they left untouched. A follow-up experiment with pristine PS foam assessed the effect of different treatments mimicking exposure to the elements on fragmentation by isopods. PS foam pieces soaked in a soil suspension were significantly more fragmented than untreated pieces or pieces exposed to UV light alone. These findings indicate that soil invertebrates may represent a source of microplastics to the environment in places polluted with PS foam trash, and that the condition of macroplastic debris likely affects its palatability to these organisms.

Anthropogenic debris in an Antarctic Specially Protected Area in the maritime Antarctic

Antarctic Specially Protected Areas (ASPAs) provide the strongest environmental protection in Antarctica. However, they are not immune from anthropogenic pollution of marine or terrestrial origin. We document anthropogenic debris within ASPA No. 133 Harmony Point, Nelson Island, recovering 1544 items between November 2019 and January 2020. The majority (82.6 %) were found close to a national operator-constructed refuge and were smaller than 5 cm. Larger items (up to 300 cm) were present on beaches and plateaus. Charcoal and rubber were the most abundant items around the refuge and plastic and metal were the most abundant items on beaches and plateaus. Debris items likely arriving in the area by marine transportation (e.g. plastic) are of concern due to both risk of ingestion and their degradation leading to the release of hazardous chemicals. Such pollution contravenes the terms of the Protocol on Environmental Protection to the Antarctic Treaty and other regionally applicable regulations.

A toxicological perspective of plastic biodegradation by insect larvae

Larvae of some insect species (Coleoptera and Lepidoptera) can consume and biodegrade synthetic polymers, including polyethylene, polystyrene, polyvinyl chloride, and polypropylene. Multiple chemical (polymer mass loss and shift of the molecular weight, alterations in chemical functionality, formation of biodegraded intermediates, CO₂ production), physical (surface hydrophobicity, thermal analysis), and biological approaches (antibiotic treatment, gut dysbiosis, isolation of plastic microbial degraders) have provided evidence for polymer biodegradation in the larva digestive tract. However, the extent and rate of biodegradation largely depend on the physicochemical structure of the polymer as well as the presence of additives. Additionally, toxicology associated with plastic biodegradation has not been investigated. This knowledge gap is critical to understand the gut symbiont-host interaction in the biodegradation process, its viability in the long term, the effects of plastic additives and their metabolites, and the phenotypic traits linked to a plastic-rich diet might be transferred in successive generations. Likewise, plastic-eating larvae represent a unique case study for elucidating the mechanisms of toxic action by micro- and nanoplastics because of the high concentration of plastics these organisms may be intentionally exposed to. This perspective review graphically summarizes the current knowledge on plastic biodegradation by insect larvae and describes the physiological processes (digestive and immune systems) that may be disrupted by micro- and nanoplastics. It also provides an outlook to advance current knowledge on the toxicity assessment of plastic-rich diets and the environmental risks of plastic-containing by-products (e.g., insect manure used as fertilizer).

Chitinase digestion for the analysis of microplastics in chitinaceous organisms using the terrestrial isopod Oniscus asellus L. as a model organism

Chitinaceous organisms have been found to ingest microplastic; however, a standardised, validated, and time- and cost-efficient method for dissolving these organisms without affecting microplastic particles is still required. This study tested four protocols for dissolving organisms with a chitin exoskeleton: 1) potassium hydroxide (KOH) + chitinase, 2) Creon® + chitinase, 3) hydrogen peroxide (H₂O₂) + chitinase, and, 4) Nitric Acid (HNO₃) + hydrogen peroxide (H₂O₂). The effects on microplastics composed of eight different polymers were also tested. The use of H₂O₂ followed by chitinase was found to be a highly efficient method. The three other protocols either did not digest the chitin sufficiently or negatively affected the tested polymers. A recovery test using microplastic fibres, beads and tyre particles revealed high recovery rates of 0.85, 0.89 and 1 respectively. This further supported the applicability of the H₂O₂ and chitinase (protocol 3) for dissolving chitinaceous organisms. Thus, we recommend that future investigations of microplastic (0.05 μm-5000 μm) in chitinaceous organisms (0.3 cm-5 cm) utilise the here presented methodology. This represents an important component of the ongoing validation and harmonization of methodological approaches that are urgently needed for the advancement of microplastic assessments globally.

New insights into the structure and function of the prokaryotic communities colonizing plastic debris collected in King George Island (Antarctica): Preliminary observations from two plastic fragments

In Antarctic regions, the composition and metabolic activity of microbial assemblages associated with plastic debris ("plastisphere") are almost unknown. A macroplastic item from land (MaL, 30 cm) and a mesoplastic from the sea (MeS, 4 mm) were collected in Maxwell Bay (King George Island, South Shetland) and analyzed by Fourier transform infrared spectroscopy in attenuated total reflectance geometry (FTIR-ATR), which confirmed a polystyrene foam and a composite high-density polyethylene composition for MaL and MeS, respectively. The structure and function of the two plastic-associated prokaryotic communities were studied by complementary 16S ribosomal RNA gene clone libraries, total bacterioplankton and culturable heterotrophic bacterial counts, enzymatic activities of the whole community and enzymatic profiles of bacterial isolates. Results showed that Gamma- and Betaproteobacteria (31% and 28%, respectively) dominated in MeS, while Beta- and Alphaproteobacteria (21% and 13%, respectively) in MaL. Sequences related to oil degrading bacteria (Alcanivorax,Marinobacter) confirmed the known anthropogenic pressure in King George Island. This investigation on plastic-associated prokaryotic structure and function represents the first attempt to characterize the ecological role of plastisphere in this Antarctic region and provides the necessary background for future research on the significance of polymer type, surface characteristics and environmental conditions in shaping the plastisphere.

Plastic ingestion as an evolutionary trap: Toward a holistic understanding

Human activities are changing our environment. Along with climate change and a widespread loss of biodiversity, plastic pollution now plays a predominant role in altering ecosystems globally. Here, we review the occurrence of plastic ingestion by wildlife through evolutionary and ecological lenses and address the fundamental question of why living organisms ingest plastic. We unify evolutionary, ecological, and cognitive approaches under the evolutionary trap theory and identify three main factors that may drive plastic ingestion: (i) the availability of plastics in the environment, (ii) an individual's acceptance threshold, and (iii) the overlap of cues given by natural foods and plastics.

Earthworms increase the potential for enzymatic bio-activation of biochars made from co-pyrolyzing animal manures and plastic wastes

We assessed the enzymatic activation of four different biochars produced from pyrolyzing swine manure and poultry litter, and by co-pyrolyzing these livestock residues with agricultural spent mulch plastic film wastes (plastichars). Enzymatic activation consisted of incubating biochars in soil inoculated with earthworms (Lumbricus terrestris), which acted as biological vectors to facilitate retention of extracellular enzymes onto biochar surface. The activity of carboxylesterase ‒a pesticide-detoxifying enzyme‒ was measured in non-bioturbed soils (reference), linings of the burrows created by earthworms, casts (feces) and biochar particles recovered from the soil. Our results revealed that: 1) biochar increased soil carboxylesterase activity respect to biochar-free (control) soils, which was more prominent in the presence of earthworms. 2) The maximum enzyme activity was found in soils amended with plastichars. 3) The plastichars showed higher enzyme binding capacities than that of the biochars produced from animal manure alone, corroborating the pattern of enzyme distribution found in soil. 4) The presence of earthworms in soil significantly increased the potential of the plastichars for enzymatic activation. These findings suggest that the plastichars are suitable for increasing and stabilizing soil enzyme activities with no toxicity on earthworms.

Addressing the environmental and health impacts of microplastics requires open collaboration between diverse sectors

Public concern over the environmental and public health impacts of the emerging contaminant class "microplastics" has recently prompted government agencies to consider mitigation efforts. Microplastics do not easily fit within traditional risk-based regulatory frameworks because their persistence and extreme diversity (of size, shape, and chemical properties associated with sorbed chemicals) result in high levels of uncertainty in hazard and exposure estimates. Due to these serious complexities, addressing microplastics' impacts requires open collaboration between scientists, regulators, and policymakers. Here we describe ongoing international mitigation efforts, with California as a case study, and draw lessons from a similarly diverse and environmentally persistent class of emerging contaminants (per- and polyfluoroalkyl substances) that is already disrupting traditional regulatory paradigms, discuss strategies to address challenges associated with developing health-protective regulations and policies related to microplastics, and suggest ways to maximize impacts of research.

Antarctic ecosystems in transition - life between stresses and opportunities

Important findings from the second decade of the 21st century on the impact of environmental change on biological processes in the Antarctic were synthesised by 26 international experts. Ten key messages emerged that have stakeholder-relevance and/or a high impact for the scientific community. They address (i) altered biogeochemical cycles, (ii) ocean acidification, (iii) climate change hotspots, (iv) unexpected dynamism in seabed-dwelling populations, (v) spatial range shifts, (vi) adaptation and thermal resilience, (vii) sea ice related biological fluctuations, (viii) pollution, (ix) endangered terrestrial endemism and (x) the discovery of unknown habitats. Most Antarctic biotas are exposed to multiple stresses and considered vulnerable to environmental change due to narrow tolerance ranges, rapid change, projected circumpolar impacts, low potential for timely genetic adaptation, and migration barriers. Important ecosystem functions, such as primary production and energy transfer between trophic levels, have already changed, and biodiversity patterns have shifted. A confidence assessment of the degree of 'scientific understanding' revealed an intermediate level for most of the more detailed sub-messages, indicating that process-oriented research has been successful in the past decade. Additional efforts are necessary, however, to achieve the level of robustness in scientific knowledge that is required to inform protection measures of the unique Antarctic terrestrial and marine ecosystems, and their contributions to global biodiversity and ecosystem services.

Biodeterioration of Untreated Polypropylene Microplastic Particles by Antarctic Bacteria

Microplastic pollution is globally recognised as a serious environmental threat due to its ubiquitous presence related primarily to improper dumping of plastic wastes. While most studies have focused on microplastic contamination in the marine ecosystem, microplastic pollution in the soil environment is generally little understood and often overlooked. The presence of microplastics affects the soil ecosystem by disrupting the soil fertility and quality, degrading the food web, and subsequently influencing both food security and human health. This study evaluates the growth and biodegradation potential of the Antarctic soil bacteria Pseudomonas sp. ADL15 and Rhodococcus sp. ADL36 on the polypropylene (PP) microplastics in Bushnell Haas (BH) medium for 40 days. The degradation was monitored based on the weight loss of PP microplastics, removal rate constant per day (K), and their half-life. The validity of the PP microplastics’ biodegradation was assessed through structural changes via Fourier transform infrared spectroscopy analyses. The weight loss percentage of the PP microplastics by ADL15 and ADL36 after 40 days was 17.3% and 7.3%, respectively. The optimal growth in the BH media infused with PP microplastics was on the 40th and 30th day for ADL15 and ADL36, respectively. The infrared spectroscopic analysis revealed significant changes in the PP microplastics’ functional groups following the incubation with Antarctic strains.