The Plasticene: Time and rocks

Pathways to reduce global plastic waste mismanagement and greenhouse gas emissions by 2050

Plastic production and plastic pollution have a negative effect on our environment, environmental justice, and climate change. Using detailed global and regional plastics datasets coupled with socioeconomic data, we employ machine learning to predict that, without intervention, annual mismanaged plastic waste will nearly double to 121 million metric tonnes (Mt) [100 to 139 Mt 95% confidence interval] by 2050. Annual greenhouse gas emissions from the plastic system are projected to grow by 37% to 3.35 billion tonnes CO2 equivalent (3.09 to 3.54) over the same period. The United Nations plastic pollution treaty presents an opportunity to reshape these outcomes. We simulate eight candidate treaty policies and find that just four could together reduce mismanaged plastic waste by 91% (86 to 98%) and gross plastic-related greenhouse gas emissions by one-third.

Assessment of transboundary macro-litter on the remote island of Andaman and Nicobar: Unveiling the governing factors and risk assessment

The increasing occurrence of mismanaged plastic litter along India's coastline and the ominous challenges it poses to biodiversity and ecosystem health is a growing environmental concern. To address this issue, we comprehensively investigated the abundance, composition, and probable sources of marine litter on North Cinque Island, a remote uninhabited island in the Andaman and Nicobar archipelago, Bay of Bengal. This island is a designated wildlife sanctuary and serves as an important nesting site for Green, Hawksbill and Leatherback turtles. A total of 6227 litter items were enumerated, with an average concentration of 0.12 items/m2, representing 20 diverse litter types, with plastic dominating the litter composition (86 %). The cleanliness and environmental hazards of the coast due to the litter were assessed using different indices such as the Clean Coast Index (CCI), Plastic Accumulation Index (PAI), Hazardous Item Index (HII), and Clean Environment Index (CEI). CCI indicates the moderately clean-to-clean status of the surveyed sites. PAI points to low to moderate accumulation of plastic litter. HII of all five coasts fell in category II, suggesting a moderate abundance of hazardous items that can inflict injuries to the foraging turtle and their hatchlings. The CEI articulates the moderately clean to very clean status of the sites. Litter brand audit suggests a considerable amount of stranded litter on the coasts was transboundary and originated from six Indian Ocean Rim Countries (IORC), namely Thailand, Myanmar, Malaysia, Indonesia, Sri Lanka, and UAE. Joint solid waste management by the IORC is the need of the hour to avert litter accumulation on the pristine, remote islands.

Biological hazards of micro- and nanoplastic with adsorbents and additives

With the increased worldwide production of plastics, interest in the biological hazards of microplastics (MP) and nanoplastics (NP), which are widely distributed as environmental pollutants, has also increased. This review aims to provide a comprehensive overview of the toxicological effects of MP and NP on in vitro and in vivo systems based on studies conducted over the past decade. We summarize key findings on how the type, size, and adsorbed substances of plastics, including chemical additives, impact organisms. Also, we address various exposure routes, such as ingestion, inhalation, and skin contact, and their biological effects on both aquatic and terrestrial organisms, as well as human health. Additionally, the review highlights the increased toxicity of MP and NP due to their smaller size and higher bioavailability, as well as the interactions between these particles and chemical additives. This review emphasizes the need for further research into the complex biological interactions and risks posed by the accumulation of MP and NP in the environment, while also proposing potential directions for future studies.

Determinants of environmental changes in human-modified ecosystems: Effects of plastics on moisture gradients, nutrients, and clay properties

Plastic pollution poses a significant threat to ecosystem health worldwide. This study examines the determinants of environmental changes in human-modified ecosystems through a quantitative-qualitative system dynamics modeling approach: field experiments conducted on a 310 m2 unsaturated clay-rich bed and a 2.5 m2 clay-rich shore of a plastic-impacted pond in Shenzhen, China, and a 1.17 ha plastic-impacted clay pit in Musanze, Rwanda; laboratory experiments involving Modified Proctor (MP) and California Bearing Ratio (CBR) tests on natural clay reinforced with polyethylene terephthalate (PET) microplastics, with diameters ranging from 0.25 to 5 mm and at concentrations of 1.25 %, 2.5 %, 3.75 %, 5 %, and 10 % by weight of clay; and plastic dynamic flows analyzed by modeling the life cycle of PET. Field experiments showed that mulch type and thickness were critical factors influencing crack distribution in a plastic-impacted pond bed. Specifically, cracks were dominant in areas with pronounced desiccation and lacking filamentous green algae and PET-dominated plastic waste. Along the 2.5 m moisture gradient in a plastic-impacted pond bed, temperature and moisture significantly influenced nutrients, particularly in pronounced desiccation zones. Laboratory experiments showed that microplastics altered the structural properties of natural clay, decreasing moisture content while increasing dry density and load-bearing capacity. The plastic life cycle underscored the roles of industrial and consumer practices, environmental conditions, and waste management and recycling inefficiencies in driving environmental changes in human-modified ecosystems. The findings underscore the need for effective plastic waste management and recycling to mitigate the ecological impacts of plastic pollution in ecosystems.

Baseline assessment of macrolitter on the coastline of Algeria: Fit-for-purpose data for tailor-made measures to navigate the Plasticene Age

Curbing the growing threat of marine litter requires reliable, coherent and fit-for-purpose data. The present study reports the findings of beach macrolitter surveys carried out in seventeen sites along the coastline of Algeria. The median litter density recorded along these sites amounted to 578 items per 100 m of coastline (range: 317-2684 items/100 m). Every surveyed beach exceeded the European threshold value of 20 items per 100 m of coastline by a significant margin. In addition, the evaluation conducted employing the Mediterranean threshold value of 130 items per 100 m of coastline indicated that each of the seventeen surveyed beaches resides within the non-Good Environmental Status spectrum. A significant proportion of the litter, accounting for 43 %, is attributed to food and beverage consumption-related items, highlighting the impact of single-use food packaging, including food and beverage containers resulting from unsustainable practices mainly by beach users and inadequate waste management.

Down to size: Exploring the influence of plastic particle Dimensions on physiological and nervous responses in early-stage zebrafish

The chorion is the first protective barrier set to prevent numerous pollutants from damaging the developing embryo. However, depending on their size, some nanoplastics (NPs) can pass through this barrier and reach the embryo, while all microplastics (MPs) remain on the outside. This study brings a straight approach to compare MPs and NPs, and assess their direct and indirect effects on zebrafish embryos and larvae. Zebrafish eggs were exposed before 2 h post fertilization (hpf) to polystyrene MPs (5 μm) and NPs (250 nm) at a concentration of 1000 μg/L until 96 hpf. Physiotoxicity and neurotoxicity were assessed prior and post-hatching through several biomarkers. Response to hypoxia (upregulation of hif-1aa and hif-1ab) were found in embryos exposed to MPs, and partly found in those exposed to NPs. Embryos exposed to NPs showed significant tachycardia, reduced O2 consumption and increased apoptosis in the eyes, whereas MPs affected the expressions of all genes related to the neurodevelopment of embryos (elavl3, pax2a, pax6a, act1b). Post-hatching, physiological responses were muted. MPs and NPs exposures ended by evaluating larval behaviours during dark-and-light cycles. Both sizes of plastic particles negatively affected the visual motor response (VMR) and vibrational startle response (VSR). Thigmotaxis levels were significantly increased by NPs whereas MPs showed anxiolytic properties. This study shows that both MPs and NPs affect the physiology and neurodevelopment of zebrafish at different levels, before and after hatching.

White tides: The plastic nurdles problem

The proliferation of plastic pollution, particularly from nurdles (small plastic pellets used in manufacturing), poses significant environmental and ecological risks. Originating with the invention of Bakelite in 1907 and escalating post-World War II with advanced petrochemical technologies, nurdles are the second largest source of primary microplastic pollution globally. Each year an estimated 445,970 tonnes of nurdles enter the environment worldwide. Nurdle spills, such as those along Spain's Galician coast and other global incidents, underline the need for improved spill response, preventive measures, and international regulatory coordination. The environmental impact of nurdles, compared to more visible oil spills, is insidious and long-lasting due to their persistence and widespread dispersion. Current regulations, like the International Maritime Organization's (IMO) guidelines, reveal gaps in enforcement and fail to fully address the long-term consequences of spills. Recent technological innovations and policy interventions aim to mitigate risks, but there's an urgent need for coordinated global action, stricter controls, and investment in biodegradable alternatives to safeguard marine environments and ensure ecological sustainability.

Microplastics dysregulate innate immunity in the SARS-CoV-2 infected lung

Introduction

Global microplastic (MP) pollution is now well recognized, with humans and animals consuming and inhaling MPs on a daily basis, with a growing body of concern surrounding the potential impacts on human health.

Methods

Using a mouse model of mild COVID-19, we describe herein the effects of azide-free 1 μm polystyrene MP beads, co-delivered into lungs with a SARS-CoV-2 omicron BA.5 inoculum. The effect of MPs on the host response to SARS-CoV-2 infection was analysed using histopathology and RNA-Seq at 2 and 6 days post-infection (dpi).

Results

Although infection reduced clearance of MPs from the lung, virus titres and viral RNA levels were not significantly affected by MPs, and overt MP-associated clinical or histopathological changes were not observed. However, RNA-Seq of infected lungs revealed that MP exposure suppressed innate immune responses at 2 dpi and increased pro-inflammatory signatures at 6 dpi. The cytokine profile at 6 dpi showed a significant correlation with the 'cytokine release syndrome' signature observed in some COVID-19 patients.

Discussion

The findings are consistent with the recent finding that MPs can inhibit phagocytosis of apoptotic cells via binding of Tim4. They also add to a growing body of literature suggesting that MPs can dysregulate inflammatory processes in specific disease settings.

Plastic litter affected by heat or pressure: A review of current research on remoulded plastic litter

Pyroplastic, plastiglomerates, anthropogenic rocks, plasticrusts, pebble clasts, plastitar, plastisoil and anthropoquinas are examples of terms that have been used to describe the secondary products of plastic litter that have been melted, moulded, pressed, or cemented together with other plastic litter and/or minerogenic sediments or organic matter, either naturally or anthropogenically. Such processes may also favor the formation of new geological features containing plastics, such as coastal landforms or sedimentary rocks. Further research and classification of this secondary plastic litter is critical for understanding the implications of this emerging contaminant as well as to create well-targeted measures to reduce it. The literature review as presented includes 32 peer-reviewed articles published between 1997 and June 2023, all of which describe various burnt or otherwise remoulded plastic litter from around the world. Based on our review we propose a new umbrella term for the different forms of secondary plastic litter that have been modified by heat or pressure: Remoulded Plastic Litter (RPL). If accepted by the research community, important steps for future research and policy will be to implement RPL into the OSPAR protocol for monitoring and assessment of marine litter and thereby fill knowledge gaps of the geographic distribution of RPLs and their potential toxicities to nature and humans. It is clear that the distribution of RPL research spans the globe, however, studies in Africa, Oceania, large tracts of the polar regions, and terrestrial areas in general, are scarce to absent, as are ecotoxicological studies and recommendations for policy development.

Marine litter weight estimation from UAV imagery: Three potential methodologies to advance macrolitter reports

In the context of marine litter monitoring, reporting the weight of beached litter can contribute to a better understanding of pollution sources and support clean-up activities. However, the litter scaling task requires considerable effort and specific equipment. This experimental study proposes and evaluates three methods to estimate beached litter weight from aerial images, employing different levels of litter categorization. The most promising approach (accuracy of 80 %) combined the outcomes of manual image screening with a generalized litter mean weight (14 g) derived from studies in the literature. Although the other two methods returned values of the same magnitude as the ground-truth, they were found less feasible for the aim. This study represents the first attempt to assess marine litter weight using remote sensing technology. Considering the exploratory nature of this study, further research is needed to enhance the reliability and robustness of the methods.

Molecular docking and metagenomics assisted mitigation of microplastic pollution

Microplastics, tiny, flimsy, and direct progenitors of principal and subsidiary plastics, cause environmental degradation in aquatic and terrestrial entities. Contamination concerns include irrevocable impacts, potential cytotoxicity, and negative health effects on mortals. The detection, recovery, and degradation strategies of these pollutants in various biota and ecosystems, as well as their impact on plants, animals, and humans, have been a topic of significant interest. But the natural environment is infested with several types of plastics, all having different chemical makeup, structure, shape, and origin. Plastic trash acts as a substrate for microbial growth, creating biofilms on the plastisphere surface. This colonizing microbial diversity can be glimpsed with meta-genomics, a culture-independent approach. Owing to its comprehensive description of microbial communities, genealogical evidence on unconventional biocatalysts or enzymes, genomic correlations, evolutionary profile, and function, it is being touted as one of the promising tools in identifying novel enzymes for the degradation of polymers. Additionally, computational tools such as molecular docking can predict the binding of these novel enzymes to the polymer substrate, which can be validated through in vitro conditions for its environmentally feasible applications. This review mainly deals with the exploration of metagenomics along with computational tools to provide a clearer perspective into the microbial potential in the biodegradation of microplastics. The computational tools due to their polymathic nature will be quintessential in identifying the enzyme structure, binding affinities of the prospective enzymes to the substrates, and foretelling of degradation pathways involved which can be quite instrumental in the furtherance of the plastic degradation studies.

Exploring marine biofouling on anthropogenic litter in the Atlantic coastline of Morocco

Today, the world is increasingly concerned about marine litter and its interaction with marine biodiversity. However, knowledge concerning the fouling organisms associated with marine litter is very limited in many of the world's marine environments. In this survey, we investigated biofouling on different types of marine litter washed up on all the coasts of the central Atlantic of Morocco. The findings revealed 21 fouling species belonging to 9 phyla (Arthropoda, Mollusca, Echinodermata, Annelida, Bryozoa, Porifera, Chlorophyta, Ochrophyta, and Ascomycota). More specifically, frequently observed fouling species include Mytilus galloprovincialis, Balanus laevis, Megabalanus coccopoma, and Pollicipes pollicipes species. Large marine litter items recorded the highest colonization of marine organisms in comparison to small ones. The frequency of occurrence (FO) of the species most commonly fouled on all coasts was Perforatus perforatus (FO = 48.60), followed by Mytilus galloprovincialis (FO = 45.80), Balanus trigonus (FO = 32.05), Balanus laevis (FO = 30.25), Megabalanus coccopoma (FO = 25.25), Bryozoa species (FO = 19.40), Spirobranchus triqueter (FO = 18.18), Lepas pectinata (FO = 14.45), and Pollicipes pollicipes (FO = 13.05). The majority of the species registered in this study are sessile. Substrate coverage by fouling taxa was significantly different between plastic substrate and other types of marine litter. Likewise, this study revealed that the proportion of fouling organisms is higher on rough surfaces. Overall, this research could be crucial to understanding the little-known subject of marine litter and its colonization by marine biota. Given that these marine litters can act as vectors and cause ecological, biogeographical, and conservation issues in the marine environment, minimizing the quantity of anthropogenic litter reaching the Moroccan Atlantic could significantly reduce its accumulation on the sea surface and seabed, thereby reducing the risk of invasion by non-indigenous species.

Human biomonitoring of microplastics and health implications: A review

BACKGROUND

Microplastics (MPs) are plastic particles (<5 mm) ubiquitous in water, soil, and air, indicating that humans can be exposed to MPs through ingestion of water and food, and inhalation.

OBJECTIVE

This review provides an overview of the current human biomonitoring data available to evaluate human exposure and health impact of MPs.

METHOD

We compiled 91 relevant studies on MPs in human matrices and MPs toxicological endpoints to provide evidence on MPs distribution in the different tissues and the implications this can have from a health perspective.

RESULTS

Human exposure to MPs has been corroborated by the detection of MPs in different human biological samples including blood, urine, stool, lung tissue, breast milk, semen and placenta. Although humans have clearance mechanisms protecting them from potentially harmful substances, health risks associated to MPs exposure include the onset of inflammation, oxidative stress, and DNA damage, potentially leading to cardiovascular and respiratory diseases, as well as cancer, as suggested by in vitro and in vivo studies.

CONCLUSION

Based on compiled data, MPs have been recurrently identified in different human tissues and fluids, suggesting that humans are exposed to MPs through inhalation and ingestion. Despite differences in MPs concentrations appear in exposed and non-exposed people, accumulation and distribution pathways and potential human health hazards is still at an infant stage. Human biomonitoring data enables the assessment of human exposure to MPs and associated risks, and this information can contribute to draw management actions and guidelines to minimize MP release to the environment, and thus, reduce human uptake.

Plastitar in the Mediterranean Sea: New records and the first geochemical characterization of these novel formations

A new geological formation consisting of plastic debris admixed to petroleum oil residue, termed "plastitar", has been recently described in the Canary Islands. Here, we report its widespread occurrence across the Mediterranean coast and new insights into its biogeochemical composition. Specifically, we found marked differences in the diagenetic stable indicator profiles, suggesting a heterogeneous seeps provenance. Moreover, the 801 plastic particles found in the 1372 g of tar surveyed, with a maximum concentration of 2.0 items/g, showed interesting patterns in the tar mat, with nurdles predominantly layered in the external of the tar mat and lines in the inner core. Overall, the collected observation suggests that tar entraps plastics through a stepwise process and is a sink for them.

Characterization of three plastic forms: Plasticoncrete, plastimetal and plastisessiles

Plastic forms, including plastiglomerate, pyroplastic, plasticrusts, anthropoquinas, plastistone and plastitar, were recorded worldwide. These plastic forms derive from geochemical or geophysical interactions such as heat-induced plastic fusion with rock in campfires, incomplete plastic combustion, water motion-driven plastic abrasion in the rocky intertidal zone, plastic deposition in hardened sediments and plastic bonding with tar. Thereby, these interactions can profoundly influence the fate of plastics in the environment. This study characterized three novel plastic forms (plasticoncrete, plastimetal and plastisessiles) discovered on Helgoland island (North Sea). Plasticoncrete consisted of common polyethylene (PE) and polypropylene (PP) fibers hardened in concrete. Plastimetal included PE fibers rusted with metal. Plastisessiles consisted of PE fibers attached to benthic substrates by sessile invertebrates (oysters and polychaetes). Plasticoncrete and plastimetal are the first plastic forms composed of two man-made materials. Plastisessiles show that plastic forms not only result from human- or environment-mediated interactions but also from biological interactions between invertebrates and plastic. All plastic forms (bulk density ≥ 1.4 g/cm3) sunk during floating tests and hardly changed their positions during a 13-day field experiment and 153- to 306-day field monitorings, indicating their local formation, limited mobility and longevity. Still, experimentally detached plastic fibers floated, confirming that the formation of these plastic forms influences the fate of plastic fibers in the environment. Furthermore, the experiment showed that plasticoncrete got deposited in beach sand under wavy and windy conditions, indicating that coastal waves and onshore winds drive plasticoncrete deposition in coastal sediments. We also provide first records of plasticoncrete on Mallorca island (Mediterranean Sea) and plastimetal on Hikoshima island (Sea of Japan), respectively, which show that these plastic forms are no local phenomena. Thereby, our study contributes to the growing fundamental knowledge of plastic forms that is essential to understand the role and fate of these pollutants in coastal habitats worldwide.

Drones for litter monitoring on coasts and rivers: suitable flight altitude and image resolution

Multirotor drones can be efficiently used to monitor macro-litter in coastal and riverine environments. Litter on beaches, dunes and riverbanks, along with floating litter on coastal and river waters, can be spotted and mapped from aerial drone images. Items detection and classification are prone to image resolution, which is expressed in terms of Ground Sampling Distance (GSD). The GSD is determined by drone flight altitude and camera properties. This paper investigates what is a suitable GSD value for litter survey. Drone flight altitude and camera setup should be chosen to obtain a GSD between 0.5 cm/px and 1.25 cm/px. Within this range, the lowest GSD allows litter categorization and classification, whereas the highest value should be adopted for a coarser litter census. In the vision of drawing up a global protocol for drone-based litter surveys, this work sets the ground for homogenizing data collection and litter assessments.

Examining the influence of COVID-19 lockdowns on coastal water quality: A study on fecal bacteria levels in Moroccan seawaters

Fecal bacteria in bathing seawater pose a substantial public health risk and require rigorous monitoring. The unexpected beach closures during the COVID-19 lockdowns have afforded unique opportunities to evaluate the impact of human activities on bathing water quality (BWQ). This study examined the temporal changes in fecal coliforms (FC) and streptococci (FS) within bathing seawater across a popular coastal region in Morocco during two lockdown periods (2020 L and 2021 L), comparing these data with observations from pre-lockdown years (2018, 2019) and post-lockdown periods (2020, 2021, 2022). Our findings illuminate the influential role the hiatus periods played in enhancing bathing water quality, attaining an "excellent" status with marked reductions in fecal coliform and streptococci levels. Consequently, the FC/FS analysis exposed a clear preponderance of humans as the primary sources of fecal contamination, a trend that aligns with the burgeoning coastal tourism and the escalating numbers of beach visitors. Additionally, the presence of domestic animals like camels and horses used for tourist rides, coupled with an increase in wild animals such as dogs during the lockdown periods, compounded the potential sources of fecal bacteria in the study area. Furthermore, occasional sewage discharge from tourist accommodations and wastewater treatment plants may also contribute to fecal contamination. To effectively mitigate these concerns and bolster public health, a commitment to relentless surveillance efforts, leveraging novel and innovative tools, is essential. These findings underline the crucial interplay between human activities and the health of our coastal ecosystems, emphasizing the need for sustainable practices for a safer and healthier future.

Assessing marine macrolitter on the coastline of the Asterousia Biosphere Reserve: Insights from a community-based study

Even in pristine and remote environments of the Mediterranean, marine litter is building up threatening habitats and species and inhibiting sustainable development. The present study reports the findings of beach litter surveys carried out by 250 local community members in nine sites along the coastline of the Asterousia Biosphere Reserve, situated in the southernmost end of Europe. The average recorded litter density along these sites amounted to 125 items per 100 meters of coastline (range: 22-510) and to 0.05 items per square meter of beach (range: 0.01-0.13). Only two of the nine surveyed beaches were found to be in good environmental status, in compliance with the European threshold value for beach litter. The other seven studied beaches surpassed the European threshold value. The primary sources of the litter identified in the study can be attributed to unsustainable practices and inadequate waste management by individuals, communities and municipalities using the coastal and marine environment. Additionally, unsustainable waste management practices within the agricultural sector were also found to be a significant contributor to marine litter pollution.

The octopus pot on the North Atlantic Iberian coast: A plague of plastic on beaches and dunes

This baseline focuses on the octopus pot, a litter item found on the North Atlantic Iberian coast. Octopus pots are deployed from vessels in ropes, with several hundred units, and placed on the seabed, to capture mostly Octopus Vulgaris. The loss of gears due to extreme seas state, bad weather and/or fishing-related unforeseen circumstances, cause the octopus pots contaminating beaches and dunes, where they are transported by sea current, waves and wind actions. This work i) gives an overview of the use of octopus pot on fisheries, ii) analyses the spatial distribution of this item on the coast, and iii) discusses the potential measures for tackling the octopus pot plague on the North Atlantic Iberian coast. Overall, it is urgent to promote conducive policies and strategies for a sustainable waste management of octopus pots, based on Reduce, Reuse and Recycle hierarchical framework.