Mitigating microplastic pollution: A critical review on the effects, remediation, and utilization strategies of microplastics

Earth: An Oxidative Planet with Limited Atom Resources and Rich Chemistry

Humanity faces an unprecedented survival challenge: climate change, driven by the depletion of natural resources, excessive waste generation, and deforestation. Six out of nine planetary boundaries have been exceeded, signaling that Earth is far from a safe operating space for humanity. In this Viewpoint Article we explore three critical "atomic-molecular" challenges: Earth's limited atomic resources, its oxidative nature, and very rich chemistry. Addressing these requires a transformation in how we produce and consume, emphasizing sustainable practices aligned with the United Nations' 17 goals. The advancement of science and technology has extended human life expectancy and improved quality of life. However, to ensure a sustainable future, we must move towards less oxidative chemical processes, incorporate CH4-CO2 redox chemistry into the circular economy, and transition from a linear, fossil fuel-dependent economy to a circular bioeconomy. Reforestation and the recovery of degraded lands are essential, alongside the shift towards green and sustainable chemistry. Earth's dynamic chemistry is governed by the principles of thermodynamics and kinetics, but science alone is insufficient. Achieving global sustainability requires coordinated economic, political, and social decisions that recognize Earth's limited resources and oxidative nature. Together, these efforts will position humanity to meet the challenges of climate change and secure a sustainable future.

Interpretable machine learning reveals transport of aged microplastics in porous media: Multiple factors co-effect

Microplastics (MPs) easily migrate into deeper soil layers, posing potential risks to subterranean habitats and groundwater. However, the mechanisms governing the vertical migration of MPs in soil, particularly aged MPs, remain unclear. In this study, we investigate the transport of MPs under varying MPs properties, soil texture and hydrology conditions. Under nearly all controlled conditions, aged MPs demonstrated a higher vertical mobility compared to virgin MPs. By employing interpretable machine learning models (IML), we not only identified the dominant role of individual parameters in the vertical migration of MPs but also discovered that the increased contribution of carbonyl index and O/C ratio in aged MPs, along with the enhanced interaction with other feature parameters, collectively promotes the elevated vertical mobility of aged MPs. The varying contributions of different feature parameters under individual control variables revealed the mechanisms of MPs vertical migration under different gradients and highlighted the dual constraints of physical obstruction and chemical retention between MPs and soil particles. The established machine learning model was also utilized to predict the differences in vertical mobilities of MPs with varying degrees of aging. The nonlinear increasing relationship between MPs vertical mobility and simulated aging time suggests that MPs can migrate to deeper soil layers shortly after entering the soil environment. The integration of laboratory experiment with IML elucidates the key drivers of vertical MP migration. It also provides a theoretical basis for the timely removal of MPs from soil and the assessment of their potential risks.

Microplastic pollution in the marine environment: Distribution factors and mitigation strategies in different oceans

As the COVID-19 pandemic began in 2020, plastic usage spiked, and microplastic (MP) generation has increased dramatically. It is documented that MP can transfer from the source to the ocean environment where they accumulate as the destination. Therefore, it is essential to understand their transferring pathways and effective environmental factors to determine the distribution of MPs in the marine environment. This article reviews the environmental factors that affect MP distribution in the oceans including abiotic such as ocean currents and wind direction, physical/chemical and biological reactions of MPs, natural sinking, particle size and settling velocity, and biotic including biofouling, and incorporation in fecal material. It was found that velocity and physical shearing are the most important parameters for MP accumulation in the deep ocean. Besides, this review proposes different research-based, national-level, and global-level strategies for the mitigation of MPs after the pandemic. Based on the findings, the level of MP pollution in the oceans is directly correlated to coastal areas with high populations, particularly in African and Asian countries. Future studies should focus on establishing predictive models based on the movement and distribution of MPs to mitigate the levels of pollution.

Enset starch-based biocomposite film reinforced with Ethiopian bentonite clay: Improved mechanical and barrier properties

Improper disposal of traditional plastics leads to the generation of microplastics, resulting in severe pollution of land and oceans and posing a threat to human health and marine ecosystems. Hence, adopting eco-friendly bioplastics, particularly in food packaging, is essential. In this study, Enset starch-based biocomposite films, reinforced with Ethiopian bentonite clay at various ratios (0, 2.5, 5, 7.5 and 10 % w/w) were prepared using solvent casting method. The effect of bentonite clay on biocomposite films on structural, physicochemical, and morphological properties were analyzed. Characterization tests confirmed the even distribution of bentonite, strengthening of bonds, and enhancement of the biocomposite film properties. The biocomposite film with 5 wt% bentonite clay incorporation into enset starch exhibits optimal performance; maximum strength (increased by 132 %), less water solubility (reduction in 33 %), reduction in water vapor permeability (decreased by 42 %), and better compatibility in the morphologies attributed by the intercalated silicate layer. This study highlights the effectiveness of bentonite clay in enhancing enset starch biocomposite properties, offering a promising eco-friendly solution for biodegradable food packaging and promoting sustainable resource utilization.

Predictive modeling of microplastic adsorption in aquatic environments using advanced machine learning models

This study addresses the critical environmental concerns surrounding microplastics, aiming to elucidate the intricate factors influencing their behavior and interactions with organic pollutants. Utilizing advanced artificial neural network modeling techniques, including GRU, LSTM, RNN, and CNN, a comprehensive analysis of microplastic sorption capacity and underlying mechanisms is conducted. The research relies on a meticulously curated dataset encompassing fundamental parameters such as organic compound composition, n-octanol/water partition coefficient, covalent acidity, covalent basicity, molecular polarizability to volume ratio, and the logarithm of the partition coefficient. Findings underscore the significance of understanding the n-octanol/water distribution coefficient (Log D) in predicting organic pollutant fate in aquatic environments, with compounds displaying higher Log D values exhibiting heightened affinity for microplastics, posing substantial ecological and human health risks. Additionally, the study highlights the importance of selecting appropriate models to accurately capture complex sorption processes, especially in varied aquatic environments. Furthermore, the profound impact of acidity, molecular polarizability to volume ratio, and covalent basicity on microplastic behavior is elucidated. Notably, machine learning models and CNNs demonstrate remarkable speed in prediction generation. A comparative analysis of four robust machine learning models establishes fundamental alignment between model predictions and empirical findings. Particularly noteworthy is the RNN model, emerging as the most accurate with an impressive accuracy of 0.967 and a minimum absolute error of 0.38. These results underscore the efficacy of the RNN model in predicting microplastic dynamics, holding promise for significant contributions to addressing microplastic pollution.

The paradox of plastic bag legislation: How bans and taxes affect PM2.5 air pollution in 208 countries

Widespread use of plastic bags contributes to elevated air pollution levels worldwide, prompting various regulatory measures such as bans and taxes aimed at reducing plastic pollution. The objective of this study was to analyze the impact of these plastic bag bans and taxes on PM2.5 air quality across 208 countries from 1960 to 2021, using Fixed Effects, Driscoll and Kraay, and GMM models. Results indicate that bans generally reduce the population's exposure to PM2.5 above WHO guidelines, but increase exposure above the Interim Target-1, while reducing it above Interim Target-3 in some models. Conversely, taxes on plastic bags significantly increase both mean annual PM2.5 exposure and the proportion of the population exposed to levels surpassing all WHO targets. The combined effect shows a decrease in exposure due to bans, except for an increase above Interim Target-3, while taxes increase exposure across all measures. These findings highlight complex interactions between plastic bag policies and air pollution, emphasizing the need for careful policy design. While plastic bag bans effectively reduce PM2.5 exposure, taxes on plastic bags unexpectedly increase it, emphasizing the need for carefully designed policies to prevent unintended increases in air pollution.

Spatiotemporal response of microplastics to natural and anthropogenic factors in estuarine waters

Riverine outflow is the primary pathway for transporting microplastics from terrestrial to marine environments, making estuaries hotspots for microplastics pollution. However, how and to what extent natural and anthropogenic factors affect the distribution of microplastics in estuarine waters remains largely unknown. A meta-analysis of 126 estuaries from 93 studies revealed a global median microplastics abundance of 196.9 items/m3, with a range from 0.007 ± 0.003 to 792,000 ± 138,000 items/m3. Microplastics were more abundant in estuaries in Asia and Oceania compared to Europe and South America. The microplastic abundance in estuarine waters was positively correlated with regional population density, per capita plastic waste, agricultural land proportion, and silt content, while the human development index (HDI) and mean annual precipitation displayed negative effects on microplastic abundance. Notably, HDI was the dominant factor influencing microplastic abundance in estuarine waters. In developing countries, microplastic abundance in estuarine waters showed positive changes, whereas it remained stable in developed countries over time. This study offers critical insights into the effects of natural and anthropogenic factors on the distribution patterns of microplastics in estuarine waters, providing important support for future management of microplastics pollution in estuaries.

Occurrence characteristics and ecological impact of agricultural soil microplastics in the Qinghai Tibetan Plateau, China

Plastic mulch is widely recognized as a significant contributor to microplastics (MPs) pollution in agricultural soil. However, its direct impact on remote areas with low population density remains uncertain due to multiple pollution sources. This study aims to investigate MPs pollution and its risks regarding agricultural soil in the Qinghai Tibetan Plateau (QTP) in China. The results revealed that soil samples from the study area exhibited a range of MPs abundance, varying from 16.67 to 950 items/kg, with the highest average abundance observed in Chengguan district (CG) soil samples (611.11 items/kg). Polyethylene terephthalate (PET), polypropylene (PP), and polyethylene (PE) were identified as the predominant components of MPs in farmland soil. Furthermore, significantly higher levels of MPs were found in the facility agriculture soil compared to the control soil. Diversity and risk of MPs in different regions and cultivation conditions were significantly different. According to the employed risk assessment models, agricultural soil demonstrated a relatively high polymer risk (47 % of areas classified as level III). In addition to being influenced by exogenous factors, the diversity of MPs also plays an intrinsic role in regulating the risk of MPs pollution. This study contributes to an enhanced comprehension of the issue of MPs pollution in QTP farmland soil, providing valuable empirical evidence and theoretical underpinning for the development of efficacious control strategies.

Water pollution and sanitation in Indonesia: a review on water quality, health and environmental impacts, management, and future challenges

As an archipelagic tropical developing country, Indonesia is characterized by vast expanses of rural and isolated areas. This review aims to discuss water pollution and sanitation's existing condition, health, and environmental impacts, alongside its management and challenges in Indonesia. The systematic review approach was utilized to ensure transparency and replicability, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. Many water sources in Indonesia are contaminated by various pollutants such as heavy metals, microplastics, pesticides, and endocrine-disrupting chemicals (EDCs). Moreover, the existing water and wastewater treatment plants cannot completely remove pollutants, including bacteria that cause waterborne diseases. The lack of proper sanitation facilities, including toilets and latrines, is not only reported in rural areas but also in peri-urban regions of Indonesia. This situation forces many to rely on unimproved water sources, such as river water, for their daily use and engage in open defecation, which may increase the risk of direct exposure to waterborne contaminants. Insufficient sanitation has been linked to significant public health issues in Indonesia, including maternal health complications, childhood stunting, and an increased incidence of waterborne diseases such as diarrhea. Based on the findings of this review, Indonesia still needs to improve its sanitation and water treatment facilities, as well as reduce pollution of the aquatic environment. This condition not only illustrates the condition of water and sanitation in Indonesia but can also be used as an illustration of how developing countries face various pollution and sanitation problems during the massive development and industry.

Microplastics from face masks: Unraveling combined toxicity with environmental hazards and their impacts on food safety

Microplastics (MPs) refer to tiny plastic particles, typically smaller than 5 mm in size. Due to increased mask usage during COVID-19, improper disposal has led to masks entering the environment and releasing MPs into the surroundings. MPs can absorb environmental hazards and transfer them to humans and animals via the food chain, yet their impacts on food safety and human health are largely neglected. This review summarizes the release process of MPs from face masks, influencing factors, and impacts on food safety. Highlights are given to the prevalence of MPs and their combined toxicities with other environmental hazards. Control strategies are also explored. The release of MPs from face masks is affected by environmental factors like pH, UV light, temperature, ionic strength, and weathering. Due to the chemical active surface and large surface area, MPs can act as vectors for heavy metals, toxins, pesticides, antibiotics and antibiotic resistance genes, and foodborne pathogens through different mechanisms, such as electrostatic interaction, precipitation, and bioaccumulation. After being adsorbed by MPs, the toxicity of these environmental hazards, such as oxidative stress, cell apoptosis, and disruption of metabolic energy levels, can be magnified. However, there is a lack of comprehensive research on both the combined toxicities of MPs and environmental hazards, as well as their corresponding control strategies. Future research should prioritize understanding the interaction of MPs with other hazards in the food chain, their combined toxicity, and integrating MPs detection and degradation methods with other hazards.

Microplastics and Co-pollutants in soil and marine environments: Sorption and desorption dynamics in unveiling invisible danger and key to ecotoxicological risk assessment

Microplastics (MPs) and their co-pollutants pose significant threats to soil and marine environments, necessitating understanding of their colonization processes to combat the plastic pandemic and protect ecosystems. MPs can act as invisible carriers, concentrating and transporting pollutants, leading to a more widespread and potentially toxic impact than the presence of either MPs or the pollutants alone. Analyzing the sorption and desorption dynamics of MPs is crucial for understanding pollutants amplification and predicting the fate and transport of pollutants in soil and marine environments. This review provides an in-depth analysis of the sorption and desorption dynamics of MPs, highlighting the importance of considering these dynamics in ecotoxicological risk assessment of MPs pollution. The review identifies limitations of current frameworks that neglect these interactions and proposes incorporating sorption and desorption data into robust frameworks to improve the ability to predict ecological risks posed by MPs and co-pollutants in soil and marine environments. However, failure to address the interplay between sorption and desorption can result in underestimation of the true impact of MPs and co-pollutants, affecting livelihoods and agro-employments, and exacerbate poverty and community disputes (SDGs 1, 2, 3, 8, 9, and 16). It can also affect food production and security (SDG 2), life below water and life on land (DSGs 14 and 15), cultural practices, and natural heritage (SDG 11.4). Hence, it is necessary to develop new approaches to ecotoxicological risk assessment that consider sorption and desorption processes in the interactions between the components in the framework to address the identified limitations.

Characteristics, sources and potential ecological risk of atmospheric microplastics in Lhasa city

Atmospheric microplastics are important contributors to environmental contamination in aquatic and terrestrial systems and pose potential ecological risks. However, studies on atmospheric microplastics are still limited in urban regions of the Tibetan Plateau, a sentinel region for climate and environmental change under a warming climate. In this study, the occurrence and potential ecological risk of atmospheric microplastics were investigated in samples of suspended atmospheric microplastics collected in Lhasa city during the Tibetan New Year in February 2023. The results show that the average abundance of atmospheric microplastics in Lhasa was 7.15 ± 2.46 MPs m-3. The sizes of the detected microplastics ranged from 20.34 to 297.18 μm, approximately 87% of which were smaller than 100 μm. Fragmented microplastics (95.76%) were the dominant shape, followed by fibres (3.75%) and pellets (0.49%). The primary polymer chemical components identified were polyamide (68.73%) and polystyrene (16.61%). The analysis of meteorological data and the backwards trajectory model indicated the air mass in Lhasa mainly controlled by westwards, and the atmospheric microplastics mainly originated from long-distance atmospheric transport. The potential ecological risk index assessment revealed that the atmospheric microplastic pollution in Lhasa was relatively low. This study provides valuable insights and a scientific foundation for future research on the prevention and control of atmospheric microplastic pollution in Lhasa and other ecologically sensitive cities.

Nano-based remediation strategies for micro and nanoplastic pollution

Due to rapid urbanization, there have been continuous environmental threats from different pollutants, especially from microplastics. Plastic products rapidly proliferate significantly contributing to the occurrence of micro-plastics, which poses a significant environmental risk. These microplastics originated from diverse sources and are characterized by their persistent and widespread occurrence; human health and the entire ecosystem are adversely affected by them. The removal of microplastics not only requires innovative technologies but also efficient materials capable of effectively eliminating them from our environment. The progress made so far has highlighted the advantages of utilizing the dimensional and structural properties of nanomaterials to increase the effectiveness of existing methods for micro-plastic treatment, aiming for a more sustainable approach to their removal. In the current review, we demonstrate a thorough overview of the sources, occurrences, and potential harmful effects of microplastics, followed by a further discussion of promising technologies used for their removal. An in-depth examination of both advantages and a few limitations of all these given technologies, including physical, chemical, and biological approaches, has been discussed. Additionally, the review explores the use of nanomaterials as an effective means to overcome obstacles and improve the efficiency of microplastic elimination methods. n conclusion, this review addresses, current challenges in this field and outlines the future perspectives for further research in this domain.

Research on the Migration and Adsorption Mechanism Applied to Microplastics in Porous Media: A Review

In recent years, microplastics (MPs) have emerged as a significant environmental pollutant, garnering substantial attention for their migration and transformation behaviors in natural environments. MPs frequently infiltrate natural porous media such as soil, sediment, and rock through various pathways, posing potential threats to ecological systems and human health. Consequently, the migration and adsorption mechanisms applied to MPs in porous media have been extensively studied. This paper aims to elucidate the migration mechanisms of MPs in porous media and their influencing factors through a systematic review. The review encompasses the characteristics of MPs, the physical properties of porous media, and hydrodynamic factors. Additionally, the paper further clarifies the adsorption mechanisms of MPs in porous media to provide theoretical support for understanding their environmental behavior and fate. Furthermore, the current mainstream detection techniques for MPs are reviewed, with an analysis of the advantages, disadvantages, and applications of each technique. Finally, the paper identifies the limitations and shortcomings of current research and envisions future research directions.

Microplastics pollution in the Surma River, Bangladesh: A rising hazard to upstream water quality and aquatic life

The ecological health of freshwater rivers is deteriorating globally due to careless human activities, for instance, the emission of plastic garbage into the river. The current research was the first assessment of microplastics (MPs) pollution in water, sediment, and representative organisms (fish, crustacean, and bivalve) from the Surma River. Water, sediment, and organisms were sampled from six river sites (Site 1: Charkhai; Site 2: Golapganj; Site 3: Alampur; Site 4: Kazir Bazar; Site 5: Kanishail and Site 6: Lamakazi), and major water quality parameters were recorded during sampling. Thereafter, MPs in water, sediment, and organism samples were extracted, and then microscopically examined to categorize selected MPs types. The abundance of MPs, as well as size, and color distribution, were estimated. Polymer types were analyzed by ATR-FTIR, the color loss of MPs was recorded, the Pollution Load Index (PLI) was calculated, and the relationship between MPs and water quality parameters was analyzed. Sites 4 and 5 had comparatively poorer water quality than other sites. Microplastic fibers, fragments, and microbeads were consistently observed in water, sediment, and organisms. A substantial range of MPs in water, sediment, and organisms (37.33-686.67 items/L, 0.89-15.12 items/g, and 0.66-48.93 items/g, respectively) was recorded. There was a diverse color range, and MPs of <200 μm were prevalent in sampling areas. Six polymer types were identified by ATR-FTIR, namely Polyethylene (PE), Polyamide (PA), Polypropylene (PP), Cellulose acetate (CA), Polyethylene terephthalate (PET), and Polystyrene (PS), where PE (41%) was recognized as highly abundant. The highest PLI was documented in Site 4 followed by Site 5 both in water and sediment. Likewise, Sites 4 and 5 were substantially different from other study areas according to PCA. Overall, the pervasiveness of MPs was evident in the Surma River, which requires further attention and prompt actions.

Case report of plastic nurdles pollution in Galicia (NW Atlantic) following the Toconao's spill in December 2023: The VIEIRA Collaborative

Plastic nurdles pose a significant environmental threat due to recurrent accidental spills into marine ecosystems. This report examines the nurdle pollution over the 1498 km of the Galician coastline (Spain) following the spill of 25 t of nurdles into the Northwest Atlantic after the loss of six containers from the Toconao vessel in December 2023. This accident highlights the urgent need for proactive, effective measures in maritime transport to prevent and mitigate such environmental catastrophes. The complexity of nurdle dispersion challenges the evaluation of their fate at sea, and the potential long-term consequences on the marine ecosystem and food web remain uncertain and yet to be investigated. This report also presents the VIEIRA collaborative and underscores the critical role of citizen-led initiatives in responding to such environmental disasters, and advocates for efficient policy reforms, involving cross-border collaboration. Furthermore, we call for greater international cooperation to underpin effective regulatory frameworks to address the growing hazard of plastic nurdle pollution worldwide.

Evaluation of potentially toxic elements and microplastics in the water treatment facility

The potentially harmful effects of consuming potentially toxic elements (PTEs) and microplastics (MPs) regularly via drinking water are a significant cause for worry. This study investigated PTEs (Cd, Cu, Cr, Ni, Pd, Zn, Co), MPs, turbidity, pH, conductivity, and health risk assessment in the water treatment plant in Kielce, Poland. Zn had the highest concentrations throughout the water treatment facility, whereas Cd, Pb, and Co had lower concentrations (< 0.1 µg/L). The order of the concentrations among the specified PTEs was like Zn˃Cu˃Ni˃Cr˃Cd˃Pb and Co. The minimum turbidity was 0.34, and the maximum was 1.9 NTU. The range of pH in water samples was 6.51-7.47. The conductivity was 1,203-1,445 ms in water samples. These identified MPs were categorized into fiber and fragments. The color of these identified MPs was blue, red, black, green, and transparent. The minimum and maximum size of the MPs was 196 and 4,018 µm, while the average size was 2,751 ± 1,905 µm. The average concentration of MPs per liter of the water treatment plant was 108.88 ± 55.61. The elements listed are C, O, Na, Mg, Al, Si, K, Ca, and Ti. Fe and Zn were the predominant elements seen using EDX. HQ values of the PTEs were less than one for adults and children. The human health risk associated with all detected PTEs revealed that the HQ values exhibit a satisfactory degree of non-carcinogenic adverse health risk. HI values for adults and children age groups were less than one. In most water treatment samples, the carcinogenic value exceeds the threshold value of 10-6. The PTEs and MP concentrations in drinking water should be periodically monitored to minimize consumers' environmental pollution and health risks.

Micro(nano)plastics: invisible compounds with a visible impact

The plastic related research has been an epicentre in recent times. The presence and spread of micro (nano) plastics (MNPs) are well-known in the terrestrial and aquatic environment. However, the focus on the fate and remediation of MNP in soil and groundwater is limited. The fate and bioaccumulation of ingested MNPs remain unknown within the digestive tract of animals. There is also a significant knowledge gap in understanding the ubiquitous organic environmental pollutants with MNPs in biological systems. Reducing plastic consumption, improving waste management practices, and developing environmentally friendly alternatives are some of the key steps needed to address MNP pollution. For better handling and to protect the environment from these invisible substances, policymakers and researchers urgently need to monitor and map MNP contamination in soil and groundwater.

Current patterns and trends of microplastic pollution in the marine environment: A bibliometric analysis

Microplastics are pervasive in the natural environment and pose a growing concern for global health. Plastic waste in marine environments has emerged as a global issue, threatening not only marine biota but also human health due to its implications for the food chain. This study aims to discern the patterns and trends of research, specifically on Marine Microplastic Pollution (MMP), based on a bibliometric analysis of scientific publications from 2011 to 2022. The methodology utilized in this study comprises three stages: (a) creating a bibliographical dataset from Scopus by Elsevier and the Web of Science Core Collection by Clarivate Analytics, (b) analyzing current research (trends and patterns) using bibliometric analysis through Biblioshiny tool, and (c) examining themes and subthemes in MMP research (wastewater treatment, plastic ingestion, the Mediterranean Sea, microplastics pollution, microplastics in freshwater, microplastic ingestion, plastic pollution, and microplastic pollution in the marine environment). The findings reveal that during the studied period, the number of MMP publications amounted to 1377 articles, with an average citation per publication of 59.23 and a total citation count of 81,553. The most cited article was published in 2011, and since then, the number of publications on this topic has been increasing steadily. The author count stood at 5478, with 22 trending topics identified from the 1377 published titles. Between 2019 and 2022, the countries contributing most to the publication of MMP articles were China, the United States of America (USA), and the United Kingdom (UK). However, a noticeable shift in the origin of author countries was observed in the 2019-2022 timeframe, transitioning from a dominance by the USA and the UK to a predominance by China. In 2019, there was a substantial increase in the volume of publications addressing the topic of microplastics. The results show that the most prevalent themes and subthemes pertained to MMP in the Mediterranean Sea. The journals with the highest number of MMP articles published were the Marine Pollution Bulletin (253 articles) and Science of the Total Environment (190 articles). The analysis concludes that research on MMP remains prominent and appears to be increasing each year.