Solutions and Integrated Strategies for the Control and Mitigation of Plastic and Microplastic Pollution

Bottled & canned - Anthropogenic debris as an understudied ecological trap for small animals

Nowadays, littering is one of the biggest challenges that environmental conservation is facing. Although beverage containers, such as bottles and cans, belong to the most common threats in this context, their effect on animals has been poorly studied. The aim of this study was to assess the diversity and mortality level of the animal taxa entering discarded containers and to investigate which container features influence the number and functional composition of the trapped animals. The study was conducted in 10 urban woodlands in the city of Wrocław, Poland. In total, 939 open containers were collected. In 56% of them, a total number of 10,162 dead individuals (10,139 invertebrates and 23 vertebrates) was found. The most common amongst them were insects (orders: Coleoptera, Diptera, Hymenoptera), malacostracans (Isopoda), arachnids (Opiliones, Sarcoptiformes) and gastropods (Stylommatophora). The number of dead animals was affected positively by the container capacity and was significantly higher in glass and plastic bottles when compared to aluminium cans. At the same time, the presence of a neck negatively affected the number of dead animals. Container capacity was also positively correlated with the abundance of the most common functional groups: predators, phytophages and saprophages. Moreover, colourless and green, but not brown, containers were a significant predictor for the abundance of the latter two groups. Our study revealed that discarded containers constitute an ecological trap for many groups of animals. There is an urgent need to reduce the amount of rubbish in the environment by, for example, the implementation of regional and international regulations addressing the problem of littering, or organising repeated clean-up and educational activities.

Process Optimization for Development of Guar Gum-Based Biodegradable Hydrogel Film Using Response Surface Methodology

In the current study, a guar-gum-based biodegradable hydrogel film was prepared using an initiator (potassium persulfate), crosslinker (N-N methyl bis acrylamide), and plasticizer (glycerol) for packaging of fruits and vegetables. The effect of independent variables (initiator, crosslinker, and plasticizer) on the biodegradation (% wt. loss), color difference (ΔE), hardness (N), swelling index (%), and transparency (%) of the film was studied using Box-Behnken design, random surface methodology (RSM). The results showed significant effects on all the abovementioned parameters, and it was observed that the developed model was accurate, with a prediction error of only -3.19 to 2.99%. The optimized formulation for the preparation of hydrogel film was 0.15% initiator, 0.02% crosslinker, and 2.88% plasticizer exhibiting satisfactory biodegradability, color difference, hardness, swelling index, and transparency. Results showed that a guar-gum-based biodegradable hydrogel film has adequate physical, optical, and biodegradable properties and can be successfully utilized in the food packaging industry.

Towards Microplastic Reduction Within Institutions

Globally, universities, institutions, and companies are aiming to reduce the use of single-use plastics as plastic litter, and plastic degradation generates secondary microplastics, all of which cause negative impacts on the environment. In this study the authors conducted a questionnaire-based survey to assess the willingness and motivation of stakeholders within academic settings to change daily habits to minimize plastic and microplastic pollution. The questionnaire, which was answered by 276 individuals with affiliation to the American Farm School or collaborating academic institutions, but primarily the American Farm School, was used to draw conclusions. Results showed that most stakeholders are ready to adapt to eliminate the use of single-use plastic within their institution and showed a high level of willingness to participate in cleaning campaigns. It is crucial to combine any new measures or policies with the proper education around why these measures are being enforced, so as to raise awareness and receptivity to those that are not familiar with microplastics and microplastic pollution.

Material flow analysis of plastic waste in the gulf co-operation countries (GCC) and the Arabian gulf: Focusing on Qatar

Global plastic waste production has increased dramatically in recent years, both globally and regionally, having a multitude of adverse effects on the environment and human health. However, little attention has been directed to this problem in the Arabian Gulf region. This study aims to delineate and map the status of the plastic waste problem in the Gulf Co-operation Countries (GCC), with a focus on Qatar. The study focuses on the plastic waste in the marine environment, depicting the different types, sizes and shapes of plastic particles found in the Arabian Gulf. To depict the flow of plastic waste, a generic material flow diagram was built using a material flow analysis software named STAN, in which transfer coefficients were assigned based on existing scientific literature and estimations built on data from local industries and recycling facilities. The recovery and recycling efforts that have been made by the different GCC countries, in efforts to reduce plastic waste and minimize the risk of plastic on the environment are analyzed, too. Our analyses indicate that approximately 11.9 Mt ± 595.395 Kt of plastic waste is produced annually in the GCC region, of which only 23 ± 15% is recycled, indicating that improvements are yet to be made in the recovery, recycling and treatment of plastics in the region. However, in Qatar, a higher percentage of plastics (40 ± 10%) is recovered-recycled with efforts to treat plastics and reuse it to generate energy.

Polyamide microplastic exposure elicits rapid, strong and genome-wide evolutionary response in the freshwater non-biting midge Chironomus riparius

Susceptibility to hazardous materials and contamination is largely determined by genetic make-up and evolutionary history of affected organisms. Yet evolutionary adaptation and microevolutionary processes triggered by contaminants are rarely considered in ecotoxicology. Using an evolve and resequencing approach, we investigated genome-wide responses of the midge C. riparius exposed to virgin polyamide microplastics (0-180 μm size range, at concentration 1 g kg^-1) during seven consecutive generations. The results were integrated to a parallel life-cycle experiment ran under the same exposure conditions. Emergence, life-cycle trait, showed first a substantial reduction in larval survival, followed by a rapid recovery within three generations. On the genomic level, we observed substantial selectively driven allele frequency changes (mean 0.566 ± 0.0879) within seven generations, associated with a mean selection coefficient of 0.322, indicating very strong selection pressure. Putative selection targets were mainly connected to oxidative stress in the microplastics exposed C. riparius population. This is the first multigenerational study on chironomids to provide evidence that upon exposure to polyamide microplastic there are changes on the genomic level, providing basis to rapid adaptation of aquatic organisms to microplastics.

About the Importance of Planning the Location of Recycling Stations in the Urban Context

Recycling is essential to the circular economy and reduces the environmental impact of our consumption. Creating conditions for recycling in new residential areas is relatively easy but finding good recycling opportunities in existing residential areas is more complicated. The recycling of newspapers, plastic and glass must be relatively close to where people live; at the same time, the locations must be relatively discreet and not disturb the residents in the area. The purpose of the article is to analyse the effect of small and local recycling stations (RCSs) on the attractiveness of residential areas. This has been made possible by analysing housing values for almost 200,000 housing units near 250 RCSs in Stockholm, Sweden. Using an identification strategy that relies on postal code fixed effects, we find evidence that the proximity to RCS affects housing prices on average in both owner-occupied single-family houses and cooperative owner-occupied apartments (condominiums). The results indicate that proximity to the RCS is negatively capitalised in housing values (the effect amounts to approximately 1.3 percent of the housing values), which indicates that the city should consider this in its planning.

Innovative co-production of polyhydroxyalkanoates and methane from broken rice

Broken rice, a low-cost starchy residue of the rice industry, can be an interesting substrate to reduce the polyhydroxyalkanoates (PHAs) production cost. However, since the most common PHAs-producing strains lack amylases, this waste must be firstly hydrolysed by additional commercial enzymes. In this work, the acidogenesis phase of the anaerobic digestion was exploited as efficient hydrolysis step to convert broken rice into volatile fatty acids (VFAs) to be used as PHAs carbon source by Cupriavidus necator DSM 545, one of the most promising PHAs-producing microbes. Broken rice, both non-hydrolysed and enzymatically hydrolysed, was processed in two continuous stirred tank reactors, at hydraulic retention times (HRT) of 5, 4 and, 3 days, to produce VFAs. The highest VFAs levels were obtained from non-hydrolysed broken rice which was efficiently exploited for PHAs accumulation by C. necator DSM 545. PHAs contents were higher after 96 h of incubation and, noteworthy, reached the highest value of 0.95 g/L in the case of 4 days HRT without any chemicals supplementation, except vitamins. Moreover, in view of a biorefinery approach, the residual solid fraction was used for methane production resulting in promising CH₄ levels. Methane yields were very promising again for 4 days HRT. As such, this HRT resulted to be the most suitable to obtain effluents with high promise in terms of both PHAs accumulation and CH₄ production. In addition, these results demonstrate that broken rice could be efficiently processed into two valuable products without any costly enzymatic pre-treatment and pave the way for future biorefining approaches where this by-product can be converted in a cluster of added-value compounds. Techno-economical estimations are in progress to assess the feasibility of the entire process, in view of supporting the low-cost conversion of organic waste into valuable products.

Amassing the Covid-19 driven PPE wastes in the dwelling environment of Chittagong Metropolis and associated implications

This study investigates the Covid-19 driven indiscriminate disposal of PPE wastes (mostly face mask and medical wastes) in Chittagong metropolitan area (CMA), Bangladesh. Based on the field monitoring, the mean PPE density (PPE/m²± SD) was calculated to be 0.0226 ± 0.0145, 0.0164 ± 0.0122, and 0.0110 ± 0.00863 for July, August, and September 2021, respectively (during the peak time of Covid-19 in Bangladesh). Moreover, gross information on PPE waste generation in the city was calculated using several parameters such as population density, face mask acceptance rate by urban population, total Covid-19 confirmed cases, quarantined and isolated patients, corresponding medical waste generation rate (kg/bed/day), etc. Moreover, the waste generated due to face mask and other PPEs in the CMA during the whole Covid-19 period (April 4, 2020 to September 5, 2021) were calculated to be 64183.03 and 128695.75 tons, respectively. It has been observed that the negligence of general people, lack of awareness about environmental pollution, and poor municipal waste management practices are the root causes for the contamination of the dwelling environment by PPE wastes. As a result, new challenges have emerged in solid waste management, which necessitates the development of an appropriate waste management strategy. The ultimate policies and strategies may help to achieve the SDG goals 3, 6, 11, 12, 13, and 15, and increase public perception on the use and subsequent disposal of PPEs, especially face masks.

Microplastics in Latin America and the Caribbean: A review on current status and perspectives

A literature review was carried out to analyze the current status of microplastic research in Latin America and the Caribbean (LAC). Specifically, this work focused on publications pertaining to (1) occurrence and distribution of microplastics in the environment, including water, sediments, and soil and (2) the environmental impact of MPs, particularly their presence and effects on aquatic and terrestrial organisms. The review included peer-reviewed articles from Scopus, Science Direct, Web of Science, Google Scholar and two iberoamerican open access databases (Redalyc and SciELO). It was found that LAC has only contributed to 5% of the global scientific output on microplastics, and overall the highest contributor within the region was Brazil (52%), followed by Chile (16%) and Mexico (13%). An additional section analyzing the barriers to conducting microplastic research in LAC and their exacerbation by the current COVID-19 pandemic was included to provide additional context behind the relatively low scientific production and improve recommendations encouraging research in this region.

Microplastics waste in environment: A perspective on recycling issues from PPE kits and face masks during the COVID-19 pandemic

During the COVID-19 pandemic, the extensive use of face masks and protective personal equipment (PPE) kits has led to increasing degree of microplastic pollution (MP) because they are typically discarded into the seas, rivers, streets, and other parts of the environment. Currently, microplastic (MP) pollution has a negative impact on the environment because of high-level fragmentation. Typically, MP pollution can be detected by various techniques, such as microscopic analysis, density separation, and Fourier transform infrared spectrometry. However, there are limited studies on disposable face masks and PPE kits. A wide range of marine species ingest MPs in the form of fibers and fragments, which directly affect the environment and human health; thus, more research and development are needed on the effect of MP pollution on human health. This article provides a perspective on the origin and distribution of MP pollution in waterbodies (e.g., rivers, ponds, lakes, and seas) and wastewater treatment plants, and reviews the possible remediation of MP pollution related to the excessive disposal of face masks and PPE kits to aquatic environments.

Disposable tri-layer masks and microfiber pollution - An experimental analysis on dry and wet state emission

The use of masks as a personal protective material is the new normal in the post-pandemic. The higher use of masks triggers immediate disposal of synthetic textile fibers leading to environmental pollution. This research is aimed to analyse the level of mask-related pollution and its impact on microfiber release. Microfiber emission characteristics of the tri-layer nonwoven mask (Polypropylene-based disposable mask) are analysed in the dry and wet stages. The individual layers of the mask and the entire mask are evaluated by subjecting them to static immersion and mechanical agitation against freshwater and seawater in the wet stage. The results of the study showed a higher microfiber shedding at dry state (14,031.97-177,601.58 fibers/mask) than the wet state (2557.65-22,525.89 fibers/mask). The increased fuzz formation in the dry state than the wet state is noted as the main reason. In the case of wet state, when the freshwater and seawater are compared, both in a static and agitated state, seawater degraded the mask highly (3358.03-27,348.9 fibers/mask) than the freshwater (1757.26-17,702.86 fibers/mask). Higher salinity and density of the seawater were noted as influencing parameters over the freshwater. When the results of naturally weathered masks are compared with the new mask, weathered masks released significantly (p < 0.05) higher amount of fibers at the evaluation stages. Similar to the new masks, the weathered masks also showed a higher amount of shedding in the dry state and presence of seawater. When the individual layers of the disposable masks were evaluated, at dry and wet states, all the layers showed a similar shedding (no significant difference between individual layers) in the case of a new mask. Whereas, after weathering, a significant amount of higher shedding (p < 0.05) is noted in the middle layer of the mask followed by the outer and inner layer. The difference in fiber composition is noted as the main reason for the strength difference of the nonwoven structure. Statistical analysis confirmed the significant impact of the natural weathering process and seawater on the microfiber shedding.

Characterization of anthropogenic marine macro-debris affecting coral habitat in the highly urbanized seascape of Mumbai megacity

Marine debris has become a major form of pollution and a serious ecosystem health concern. The present study evaluates the accumulation, origin, and fate of debris in intertidal coral habitats of Mumbai-one of the world's highly populated coastal cities on the west coast of India. Predominantly, seven hermatypic coral species belonging to seven genera and five families were identified and mainly represented by Pseudosidastrea, Porites, and Bernardpora. In terms of number, the mean density of marine debris was 1.60 ± 0.13 SE items/m², which is higher than the global average. The mean density of plastic debris was 1.46 ± 0.14 SE items/m². Approximately 9% of total coral colonies were in physical contact with debris, and 22% of these colonies showed visible signs of partial bleaching. Single use plastic bags and wrappers were dominant plastic debris. The study area was characterized as 'very poor cleanliness' according to the Beach Quality Indexes, which include the Clean Coast Index, General Index, and Hazardous Items Index. The numerical model indicates the influence of river discharge and probable areas of plastic accumulation with high tidal currents in this region, maneuvering the spatial advection of litter in the nearshore areas. Combined analysis of ground-truthing and model simulation implies that the possible contributing sources of litter were representatives of land-based and sea-originated. The overall results point to increasing anthropogenic stressors threatening coastal coral communities, including marine debris pollution. It is advocated to adopt an integrated coastal zone management approach supported by coordinated policy frameworks could guide the mitigation of the debris footprint in coastal environments.

Occurrence of microplastics (MPs) in the gastrointestinal tract of fishes: A global systematic review and meta-analysis and meta-regression

The presence of Microplastics (MPs) in food has become a global health concern in the last two decades. In this study, an attempt was made to obtain articles about the occurrence of MPs in the gastrointestinal tract (gt) of fishes using searching the Scopus and PubMed databases from 1 January 1990 to 10 August 2021. The occurrence of MPs was meta-analyzed using the random effect model (REM). The results indicate that pooled occurrence of MPs in gastrointestinal of fishes was 2.76 P/gt: 95%CI:2.65-2.86 P/gt. Occurrence MPs in gastrointestinal of fishes in closed water sources (5.86 P/gt) was higher than free water sources (2.46 P/gt). In addition, the rank order of water sources based on occurrence MPs in gastrointestinal of fish was Lake (5.50 P/gt) > Estuary (5.46 P/gt) > River (2.91 P/gt) > Bay (2.85 P/gt) > Sea (2.58 P/gt) > Ocean (1.29 P/gt). The lowest and highest occurrence MPs in gastrointestinal of fishes were observed in high-income economies (1.45 P/gt) and low-income economies (8.08 P/gt), respectively. The higher frequency of color in MPS was related to blue with polyethylene-type polymers. Therefore, control plans to reduce the occurrence of MPs in fishes is recommended.

PPE pollution in the terrestrial and aquatic environment of the Chittagong city area associated with the COVID-19 pandemic and concomitant health implications

The present study focuses on the indiscriminate disposal of personal protective equipment (PPEs) and resulting environmental contamination during the 3rd wave of COVID-19-driven global pandemic in the Chittagong metropolitan area, Bangladesh. Because of the very high rate of infection by the delta variant of this virus, the use of PPEs by the public is increased significantly to protect the ingestion/inhalation of respiratory droplets in the air. However, it is a matter of solicitude that general people throw away the PPEs to the dwelling environment unconsciously. With the increase of inappropriate disposal of PPEs (i.e., mostly the disposable face masks made from plastic microfibers), the possibility of transmission of the virus to the general public cannot be neglected completely. This is because this virus can survive for several days on the inanimate matter like plastics and fibers. At the same time, the result of environmental contamination by microplastic/microfiber has been widespread which eventually creates the worst impact on ecosystems and organisms. The present results may help to increase public perception of the use and subsequent disposal of PPEs, especially the face masks.

Mechanical Properties and Tensile Model of Hemp-Fiber-Reinforced Poly(butylene adipate-co-terephthalate) Composite

The preparation of a high-strength biodegradable plastic has always been the focus of academia. Here, we prepared two biodegradable composites using silane coupling-agent-modified hemp fibers (Si-HF) and unmodified hemp fibers (HF) with butylene adipate-co-terephthalate (PBAT), respectively. We compared the differences of Si-HF/PBAT and HF/PBAT in terms of micromorphology, density, mechanical properties, thermal stability and biodegradability. The Si-HF has better interface interaction between the hemp and the PBAT matrix than the HF, which makes Si-HF/PBAT have better tensile properties. Moreover, Si-HF/PBAT has stronger tensile strength and modulus than HF/PBAT. Our results also show that the two composites have good biodegradability. This study provides an important reference for the subsequent development and utilization of hemp fibers.

Evaluating Canada's single-use plastic mitigation policies via brand audit and beach cleanup data to reduce plastic pollution

Single-use plastics (SUPs) represent a major threat to marine environments and require proactive policies to reduce consumption and mismanagement. Many SUP management strategies exist to reduce SUP use and mitigate environmental impacts, including extended producer responsibility (EPR), deposit-return schemes, SUP bans or taxes, and public outreach and education. This study analyzed brand audit and beach cleanup data in four densely populated Canadian cities (Vancouver, Toronto, Montréal, Halifax) and a remote island (Sable Island) to determine efficacy of ongoing SUP mitigation measures. Cities were found to have similar litter type proportions, and six brands were found to disproportionally contribute to Canadian SUP litter, comprising 39% of branded litter collected. Results confirm that current Canadian SUP management appears to be insufficient to address leakage of SUPs into the environment. Recommendations to strengthen SUP management strategies and mitigate plastic pollution are recommended to improve future Canadian SUP reduction policies.

Eco-friendly masks preferences during COVID-19 pandemic in Indonesia

Eco-friendly face mask is necessity to reduce the aggravates the environment due to increased face masks waste during COVID-19 pandemic. The successful eco-friendly masks development influenced by understanding of user’s need and effectiveness of communications. The employed conjoint analysis obtained user mask preferences information to support effective communication strategies by business enterprises and policy makers on encouraging public to consume appropriate masks. The attribute importance followed from eco-friendly (32.1%), mask certification (26.5%), filtration efficiency (19.8%), price (13.9%), layers (5.6%), type of mask (1.5%), material (0.7%). The public expecting the mask with the ability to recycled and biodegradable, with certification, performance above 90% filtration efficiency, and affordable prices in the range of Rp.1.500-Rp.25.000. Also, 3-ply fabrics for the medical type and cotton material are generally preferred to polyester/polypropylene. The government needs to improve the effectiveness masks education, provide convenience process to masks certification by manufacturers, and provision of incentives to reduce masks production cost. Meanwhile, manufacturers ensure produce of the standard eco-friendly masks in affordable pricing. Furthermore, gender did not show significant effect on preferences, but varied with average expenditure.

Recent Advances in Biological Recycling of Polyethylene Terephthalate (PET) Plastic Wastes

Polyethylene terephthalate (PET) is one of the most commonly used polyester plastics worldwide but is extremely difficult to be hydrolyzed in a natural environment. PET plastic is an inexpensive, lightweight, and durable material, which can readily be molded into an assortment of products that are used in a broad range of applications. Most PET is used for single-use packaging materials, such as disposable consumer items and packaging. Although PET plastics are a valuable resource in many aspects, the proliferation of plastic products in the last several decades have resulted in a negative environmental footprint. The long-term risk of released PET waste in the environment poses a serious threat to ecosystems, food safety, and even human health in modern society. Recycling is one of the most important actions currently available to reduce these impacts. Current clean-up strategies have attempted to alleviate the adverse impacts of PET pollution but are unable to compete with the increasing quantities of PET waste exposed to the environment. In this review paper, current PET recycling methods to improve life cycle and waste management are discussed, which can be further implemented to reduce plastics pollution and its impacts on health and environment. Compared with conventional mechanical and chemical recycling processes, the biotechnological recycling of PET involves enzymatic degradation of the waste PET and the followed bioconversion of degraded PET monomers into value-added chemicals. This approach creates a circular PET economy by recycling waste PET or upcycling it into more valuable products with minimal environmental footprint.

Microplastics in equatorial coasts: Pollution hotspots and spatiotemporal variations associated with tropical monsoons

Microplastics (MP < 5 mm) are eroding oceanic health and coastal development at a planetary scale. Coastlines in Southeast Asia (SEA) are plagued with plastic litters, but how MP are dispersed within SEA region is poorly understood, which can vary dramatically under the tropical climate. We systematically quantified MP in equatorial Singapore, to assess how prevailing Monsoons and other factors impact MP distributions in beaches and mangroves. Data highlighted spatial preponderance differed broadly by seasons (p < 0.05) and were strongly modulated by wind speediness (p < 0.05; r = 0.6-0.7) and promoted transboundary migrations of MP. Conversely, an inverse relationship existed between sediment MP and rainfall (r = -0.54) possibly due to re-entrainment of surficial MP. Elevated concentrations in mangrove's compartments (p < 0.05) suggest effective repository hotspots. Coastal MP consisted assorted morphologies and commonest polymers including 34% polypropylene (PP), 26% polyethelene (PE), and 23% Low Density PE. Further comparisons revealed coastal MP in Singapore accelerated by two orders of magnitude since 2014, implying cumulative pollution which is not reversible. We synthesized the first seasonal coastal MP report in SEA which is useful for source apportionment, prediction study, and mitigation planning under tropical circumstances.

A critical review of microplastics in the soil-plant system: Distribution, uptake, phytotoxicity and prevention

Microplastics (MPs) are creating an emerging threat on the soil ecosystems and are of great global concern. However, the distribution in soil-plant system, as well as the phytotoxicity and impact mechanisms of MPs remain largely unexplored so far. This study introduced the diverse sources of MPs and showed the significant spatial variation in the global geographic distribution of MPs contamination based on data collected from 116 studies (1003 sampling sites). We systematically discussed MPs phytotoxicity, such as plant uptake and migration to stems and leaves, delaying seed germination, impeding plant growth, inhibiting photosynthesis, interfering with nutrient metabolism, causing oxidative damage, and producing genotoxicity. We further highlighted the alterations of soil structure and function by MPs, as well as their self and load toxicity, as potential mechanisms that threaten plants. Finally, this paper provided several preventive strategies to mitigate soil MPs pollution and presented research gaps in the biogeochemical behavior of MPs in soil-plant systems. Meanwhile, we recommended that methods for the quantitative detection of MPs accumulated in plant tissues should be explored and established as soon as possible. This review will improve the understanding of the environmental behavior of MPs in soil-plant systems and provide a theoretical reference to better assess the ecological risk of MPs.

Tripartite Evolutionary Game Analysis for Plastic Pollution Prevention and Control under the Background of China’s Plastic Ban

Controlling plastic pollution is an important issue in the field of sustainable development and is of great concern for numerous countries’ governments. After investigating the implementation of relevant policies, this paper analyzes the tripartite mainstay under the background of China’s Plastic Ban by constructing an evolutionary game model involving governments, enterprises and the public. Through simulation modeling, the paper then investigates the possible regulatory effects of different policies at the micro level. According to the results, the government should pay more attention to how it reacts to enterprises’ compliance strategies, both for the sake of the public and itself. It is vital to increase enterprises’ compliance rewards and decrease their compliance costs through various means such as policy changes and technological innovation. The policy’s effect can be improved if supervision and regulations are both enforced.

Updated review on microplastics in water, their occurrence, detection, measurement, environmental pollution, and the need for regulatory standards

The gravity of the impending threats posed by microplastics (MPs) pollution in the environment cannot be over-emphasized. Several research studies continue to stress how important it is to curb the proliferation of these small plastic particles with different physical and chemical properties, especially in aquatic environments. While several works on how to monitor, detect and remove MPs from the aquatic environment have been published, there is still a lack of explicit regulatory framework for mitigation of MPs globally. A critical review that summarizes recent advances in MPs research and emphasizes the need for regulatory frameworks devoted to MPs is presented in this paper. These frameworks suggested in this paper may be useful for reducing the proliferation of MPs in the environment. Based on all reviewed studies related to MPs research, we discussed the occurrence of MPs by identifying the major types and sources of MPs in water bodies; examined the recent ways of detecting, monitoring, and measuring MPs routinely to minimize projected risks; and proposed recommendations for consensus regulatory actions that will be effective for MPs mitigation.

Knowledge and perception of different plastic bags and packages: A case study in Brazil

The growing demand for plastics, for packaging and consumption, is a current environmental issue. Although there are many scientific developments concerning material science, knowledge about the public's perception is low, which can delay society's efforts to face this challenge. This study aimed to understand if Brazilians who practice different sustainable actions perceive differently biodegradable, recycled, and common plastics and have different purchase intentions for each specific type of packaging. A total of 1080 Brazilian adults were first classified by their day-to-day attitudes regarding sustainability efforts. Then, their purchase intention and perception about different plastics were assessed. Regardless of sustainability practices, people associate common plastic bags with negative attributes and biodegradable plastic bags with positive attributes. This shows that there is a well-established concept about these types of bags, even if there are some misconceptions (e.g. recyclable) or controversies (e.g. non-polluting). On the other hand, results showed that consumers who adopted more sustainable practices were 3.5 times more willing to pay for biodegradable packages, even though no differences were observed in the accepted price for biodegradable bags between consumer's groups. Finally, the purchase intention comparisons for products packaged in recycled and biodegradable plastics showed the consumers were more interested in those biodegradable plastics and the purchase intention was lower for perishable food (e.g. products that can have higher safety risks). The results are important for understanding environmental policy management in Brazil, highlighting the importance to improve the population's knowledge about different types of plastic, leading to more conscious choices.

Micro/nano-plastics occurrence, identification, risk analysis and mitigation: challenges and perspectives

Micro/nanoplastics (MP/NPs) are emerging global pollutants that garnered enormous attention due to their potential threat to the ecosystem in virtue of their persistence and accumulation. Notably, United Nations Environment Programme (UNEP) yearbook in 2014 proposed MPs as one among ten emergent issues that the Earth is facing today. MP/NPs can be found in most regularly used products (primary microplastics) or formed by the fragmentation of bigger plastics (secondary microplastics) and are inextricably discharged into the environment by terrestrial and land-based sources, particularly runoff. They are non-degradable, biologically incompatible, and their presence in the air, soil, water, and food can induce ecotoxicological issues and also a menace to the environment. Due to micro size and diverse chemical nature, MP/NPs easily infiltrate wastewater treatment processes. This communication reviews the current understanding of MP/NPs occurrence, mobility, aggregation behavior, and degradation/assimilation in terrestrial, aquatic (fresh & marine), atmospheric depositions, wetlands and trophic food chain. This communication provide current perspectives and understanding on MP/NPs concerning (1) Source, occurrence, distribution, and properties (2) Impact on the ecosystem and its services, (3) Techniques in detection and identification and (4) Strategies to manage and mitigation.

Coastal gradients of small microplastics and associated pollutants influenced by estuarine sources

Small microplastics (SMPs) in the gulf of Cadiz was sampled at 5 m depth by pumping it through the ship's pipe system and filtered through a 45 μm mesh size net. Our study reveals that higher densities have been found (130 mg·m^-3) compared to other regions worldwide and these densities decreased from the coastline to the outer stations, showing a general coastal gradient influenced by estuarine outflows. SMPs with a size range between 45 and 193 μm were predominant and most of them composed by polyethylene and polypropylene. The metals associated with the MPs were mainly Na (21.1%), K (11.3%), Fe (8.5%), Ca (2.1%), Cr (1.8%), Zr (13.3%) and Hf (0.7%). The high proportion of Zr compared to Fe, which is different from what can be found in the environment, suggests that this metal is intrinsic to the materials used in catalytic processes during plastic production.

The road to sustainable use and waste management of plastics in Portugal

As a European Union (EU) member, Portugal must comply with reductions in plastic waste. In Portugal, the 330 items/100 m of beach litter, comprising up to 3.9 million pieces and of which 88% is plastic, is higher than the EU median (149 items/100 m) and must be reduced to 20 items/100 m (94%). Integrative measures are needed to reduce littering and improve plastics' use and disposal under the circular economy. Of this 414 kt of plastic packaging waste, 163 kt were declared plastic packaging, 140 kt subjected to recycling, and 94 kt to energy recovery. The current recycling rate of plastic packaging (34%) should be improved to reach EU recycling averages (42%) and goals and to provide widespread benefits, considering revenues of 167 €/t. As a net importer of waste, Portugal could benefit from the valorization of imported waste. Besides increased recycling, pyrolysis and gasification could provide short-term alternatives for producing value-added substances from plastic waste, such as hydrogen, consistent with the National Plan of Hydrogen and improving ongoing regulations on single-use plastics. This manuscript provides an integrative view of plastics in Portugal, from use to disposal, providing specific recommendations under the circular economy.

ELECTRONIC SUPPLEMENTARY MATERIAL

Supplementary material is available in the online version of this article at 10.1007/s11783-021-1439-x and is accessible for authorized users.

On the way to reduce marine microplastics pollution. Research landscape of psychosocial drivers

Current human lifestyle generates enormous amounts of plastics and microplastics that end in the ocean and threaten marine life. Exposure to microplastics seems to threaten human health too. Although the degree of damage is not clear yet, precautionary approach urgently requires a change of societal habits. The objective of this study was to discover emerging issues of priority for psychosocial investigation. For this we have compared the landscape research of Reviews with that of Perspectives articles of the last decade, to identify mismatches that unravel still understudied subjects. Results revealed that circular economy is a focus in Perspectives but is not main topic of current psychosocial research. Regarding the actors involved in the change towards circular economy, although companies are priority in Perspectives current research is focused on consumers. Results suggest the need for more efforts on the investigation of corporative responsibility in the way to stop microplastics pollution.

Marine debris database development using international best practices: A case study in Vietnam

Marine debris, particularly plastic debris is a ubiquitous global pervasive problem. The international community recognizes that a reduction in plastic debris density is central to sustainable ocean use based on reduction performance metrics. Although many national databases already exist or are being developed, an internationally accepted index of plastic debris density does not currently exist. Standardized methods for monitoring marine debris can help inform policy decisions to reduce sources marine debris and support mitigation effectiveness. Vietnam recently committed to addressing marine debris nationally and internationally and developed ambitious targets to manage and reduce ocean plastic debris, yet Vietnam does not currently have a national marine debris monitoring database. This study identified international best practices and standards; developed a marine plastic database for accurate, efficient information gathering, management, and reporting; and developed a centralized database platform for future marine plastic debris management in Vietnam that can be adapted for other jurisdictions.

Plastic waste footprint in the context of COVID-19: Reduction challenges and policy recommendations towards sustainable development goals

The sudden surge in demand to use plastic products due to COVID-19 pandemic has increased plastic pollution. It has resulted into degradation of a broad range of habitats and ecosystems by destroying natural functions, water quality, and environmental sustainability. However, the government agencies, scientific communities, and the public, have started to give attention to this issue. So, in the present study, we used the correlation methods to check the relationship between COVID-19 affected population with the medical plastic waste (MPW) that has developed a conceptual model of the inter-linkages between the preventive measures of COVID-19 pandemic problems and the reduction challenges of plastic waste during and after pandemic scenarios. Emerging issues in the waste management during and after the COVID-19 are established by reviewing the literature, reports, policy briefs, and information from the website concerning COVID-19. Considering MPW management issues, we selected India as a case study to analyse the plastic waste footprint (PWF) due to COVID-19 pandemic. The correlation results showed COVID-19 affected population and MPW; COVID-19 affected population and PWF have a significant relationship (R² = 0.60; Area under ROC curve 81.4%). It suggests an urgent need for plastic waste management initiatives. Moreover, substantial plastic products, human awareness, strict government regulations, and inclusive research can check plastic waste footprints in India and worldwide. Then discuss the specific pathways through which the immediate and long-term impacts operate and highlight the issues of hampering the sustainable development goals (SDGs) progress in India and beyond. Finally, call for coordinated assessment, support and appropriate short- and long-term mitigation and the policy measures of plastic waste problems during and after the COVID-19 pandemic.

Assessment of the reuse of Covid-19 healthy personal protective materials in enhancing geotechnical properties of Najran's soil for road construction: Numerical and experimental study

The COVID-19 pandemic has not only caused a global health crisis, but it has also had significant environmental and human consequences. During the COVID-19 pandemic, this study focused on emerging challenges in managing healthy personal protective materials (HPPM) in Kingdom of Saudi Arabia, using silty sand (SM) soil as an example since it covers large areas in KSA and in the whole world. The main objective of this paper is to find a novel way to minimize pandemic-related waste by using HPPM as waste materials in road construction. For the first time, a series of experiments was conducted on a mixture of different percentages of shredded HPPM (0, 0.5, 1 and 2%) added to the silty sand (SM) soil for road applications, including soil classification according to the USCS, modified compaction, UCS, UPV, and CBR. In addition, a numerical simulation was performed using geotechnical-based software Plaxis 3D to study the performance of the soil-HPPM mix as a subbase layer in the paving structure under heavy traffic loading. The modified compaction test results show that there is an increase in the optimum moisture content with increasing the HPPM contents from 0.5% to 1% and 2%. However, a reduction in the maximum dry density is observed. The values of dry density and water content at 0%, 0.5%, 1% and 2% pf HPPM are 2.045, 1.98, 1.86 and 1.8 g/cm³ and 7.65% 8%, 8.5% and 9.5%, respectively. The soaked CBR values at 0, 0.5, 1 and 2% HPPM are 23, 30, 8, 2% with the maximum value attained with the addition of 0.5% HPPM. The results of UCS were with the same percentages of HPPM 430, 450, 430 and 415 kPa, respectively, with the maximum value attained with 0.5% HPPM addition as well. In contrast, the values of UVP at 0%, 0.5%, 1% and 2% are 978.5, 680.3, 489.4 and 323.6 m/s, respectively, confirming the trends obtained by modified compaction test results. The simulation results confirm this conclusion that the soil-HPPM mix show a superior performance when used as a subbase layer and reduced vertical displacement by a percentage of 11% compared to the normal subbase material. By eliminating HPPM especially facemasks from the landfill lifecycle, incorporating them into high quality construction material production has the potential to deliver significant environmental benefits.

Strategic Approach Towards Plastic Waste Valorization: Challenges and Promising Chemical Upcycling Possibilities

Plastic waste, which is one of the major sources of pollution in the landfills and oceans, has raised global concern, primarily due to the huge production rate, high durability, and the lack of utilization of the available waste management techniques. Recycling methods are preferable to reduce the impact of plastic pollution to some extent. However, most of the recycling techniques are associated with different drawbacks, high cost and downgrading of product quality being among the notable ones. The sustainable option here is to upcycle the plastic waste to create high-value materials to compensate for the cost of production. Several upcycling techniques are constantly being investigated and explored, which is currently the only economical option to resolve the plastic waste issue. This Review provides a comprehensive insight on the promising chemical routes available for upcycling of the most widely used plastic and mixed plastic wastes. The challenges inherent to these processes, the recent advances, and the significant role of the science and research community in resolving these issues are further emphasized.

The challenges of Covid-19 pandemic on improving plastic waste recycling rates

The plastic system is burdened with many inefficiencies that have been exposed, and exacerbated, by the outbreak of the coronavirus (SARS-CoV2) pandemic in December 2019, widely known as COVID-19, and which threaten society's commitment to transition to a sustainable plastics economy. This perspective aims to depict the structural and systemic inefficiencies of the plastics system, and illuminate: (a) the vulnerability of the recycling sector to macroeconomic - particularly to oil price - shocks; (b) the economics of the recycling system; (c) the political dimensions of the plastics sector. It emphasises that is unwise to think about plastics recycling as an insular and linear problem, due to the complexity and interconnectedness of different parts of the plastic system that affect and are affected by the intertwined processes, stakeholders and values. That said, the transition to a sustainable plastics system requires an integrated, knowledge-based systems approach that interrogates the dynamics and causal-effect relationships of the interconnected challenges. This analytical scrutiny can indicate where interventions are needed in the plastics system towards creating transformational change.

Impacts of Plastic Pollution on Ecosystem Services, Sustainable Development Goals, and Need to Focus on Circular Economy and Policy Interventions

Plastic pollution is ubiquitous in terrestrial and aquatic ecosystems. Plastic waste exposed to the environment creates problems and is of significant concern for all life forms. Plastic production and accumulation in the natural environment are occurring at an unprecedented rate due to indiscriminate use, inadequate recycling, and deposits in landfills. In 2019, the global production of plastic was at 370 million tons, with only 9% of it being recycled, 12% being incinerated, and the remaining left in the environment or landfills. The leakage of plastic wastes into terrestrial and aquatic ecosystems is occurring at an unprecedented rate. The management of plastic waste is a challenging problem for researchers, policymakers, citizens, and other stakeholders. Therefore, here, we summarize the current understanding and concerns of plastics pollution (microplastics or nanoplastics) on natural ecosystems. The overall goal of this review is to provide background assessment on the adverse effects of plastic pollution on natural ecosystems; interlink the management of plastic pollution with sustainable development goals; address the policy initiatives under transdisciplinary approaches through life cycle assessment, circular economy, and sustainability; identify the knowledge gaps; and provide current policy recommendations. Plastic waste management through community involvement and socio-economic inputs in different countries are presented and discussed. Plastic ban policies and public awareness are likely the major mitigation interventions. The need for life cycle assessment and circularity to assess the potential environmental impacts and resources used throughout a plastic product’s life span is emphasized. Innovations are needed to reduce, reuse, recycle, and recover plastics and find eco-friendly replacements for plastics. Empowering and educating communities and citizens to act collectively to minimize plastic pollution and use alternative options for plastics must be promoted and enforced. Plastic pollution is a global concern that must be addressed collectively with the utmost priority.

Plastic waste associated with the COVID-19 pandemic: Crisis or opportunity?

Coronavirus Diseases 2019 (COVID-19) pandemic has a huge impact on the plastic waste management in many countries due to the sudden surge of medical waste which has led to a global waste management crisis. Improper management of plastic waste may lead to various negative impacts on the environment, animals, and human health. However, adopting proper waste management and the right technologies, looking in a different perception of the current crisis would be an opportunity. About 40% of the plastic waste ended up in landfill, 25% incinerated, 16% recycled and the remaining 19% are leaked into the environment. The increase of plastic wastes and demand of plastic markets serve as a good economic indicator for investor and government initiative to invest in technologies that converts plastic waste into value-added product such as fuel and construction materials. This will close the loop of the life cycle of plastic waste by achieving a sustainable circular economy. This review paper will provide insight of the state of plastic waste before and during the COVID-19 pandemic. The treatment pathway of plastic waste such as sterilisation technology, incineration, and alternative technologies available in converting plastic waste into value-added product were reviewed.

Use and misuse of FTIR spectroscopy for studying the bio-oxidation of plastics

Due to massive production, inefficient waste collection, and long lives, plastics have become a source of persistent pollution. Biodegradation is explored as an environmentally friendly remediation method for removing plastics from the environment. Microbial and animal biodegradation methods have been reported in the literature for various plastics. Levels of plastic oxidation are often used as an evidence of degradation and can be measured with great sensitivity by Fourier Transform Infrared (FTIR) spectroscopy. FTIR is highly sensitive to the creation of new CO, CO and OH bonds during oxidation. However, many studies reporting the use of FTIR spectroscopy to evidence plastic oxidation confused the spectral signatures of biomass contamination (CO and CO from lipids, CONH from proteins, O-H from polysaccharides) with plastic oxidation. Here, based on spectra of oxidized plastic and of probable contaminants, we make recommendations for performing and analyzing FTIR measurements properly.

Single-Use Plastic Bans: Exploring Stakeholder Perspectives on Best Practices for Reducing Plastic Pollution

In this study, we conducted and documented workshops and interviews in Norway and Slovenia to identify stakeholder and future generation opinions and mitigation strategies for solving one of the most prominent environmental issues: plastic pollution. As part of the EU H2020 project GoJelly, stakeholders were brought together to explore their perceptions on considering jellyfish mucus as a new resource to contribute to reducing plastic pollution from entering the marine environment. The study was conducted in the spring of 2019, in a context directly after the European Union (EU) announced its Directive to ban the most commonly used single-use plastic (SUP) items. The study applied the snowball method as a methodological choice to identify relevant stakeholders. Systems thinking was utilized as a participatory modelling approach, which allowed for the creation of conceptual mind maps from the various workshops and interviews, to understand consumers’ consciousness, and to map out ideas on plastic pollution reduction. Plastic pollution takes place on a global scale and stakeholders discussed their individual perceptions of national and international solutions that could be put in place to solve it, including the opportunities around utilizing jellyfish mucus to filter and capture micro- and nanoplastic. We found that industry stakeholders in both case areas were generally more accepting of policy and increased innovation moving forward, but placed weight on the scientific community to conduct more research on the pollution issue and propose solutions. Future generation stakeholders (youth aged 14–18), however, put emphasis on consumer behavior and buying patterns of single-use products fueling the plastic crisis.

First evidence of microplastics occurrence in mixed surface and treated wastewater from two major Saudi Arabian cities and assessment of their ecological risk

In this study, water of the channels and ponds that conduct residual water in two most important cities of Saudi Arabia were assessed to ascertain the influence of the population on the occurrence and pollution characteristics of microplastics (MPs) (> 20 µm in size). Riyadh has 7.6 million inhabitants and is an urban city even though also have industry while Al-Jubail has only 0.78 and is the biggest industrial city. MPs showed an average of 3.2 items/L in Riyadh and 0.2 items/L in Al-Jubail showing a statistically significant difference between both cities. Sampling with a Turton Tow Net of 20 µm mesh, fibers were dominant in all sites (60%). MPs size was mainly distributed between 80 and 250 µm (60%), and their major colors were white (40%), red (25%) and blue (20%). Infrared spectral analysis revealed that most of the selected particles were identified as MPs of polypropylene and polyethylene (48.3%). The risk assessment was carried out using both the hazard index (HI) and the pollution load index (PLI). The results showed that, in this case, the decisive index is the PLI since the main difference in the MPs characteristics between the two cities is their concentration.

Plastic Pollution by COVID-19 Pandemic: An Urge for Sustainable Approaches to Protect the Environment

COVID-19 pandemic has created a prolonged impact globally and destructed the life all over the world. The necessary use of personal protective equipments, masks, gloves and other plastic products has to some extent reduced transmission of virus. However, the impact of plastic waste generated worldwide due to the pandemic has affected the environment globally. The coronavirus disease (COVID-19) has destructed and altered every part of life and environment globally. Potential impacts on the environment are seen due to the transmission of virus as well as a slowdown in economic activities as lockdown prevails. Increased biomedical waste, improper usage and disposal of surgical masks, disinfectants, gloves, and increasing plastics wastes from domestic households continuously endangers environment. Not only it has an impact on environment, but also deteriorates human health in the future. Global environmental sustainability is necessitated to overcome the plastic pollution problem and facilitate strategies to recycle and reuse plastics products. This review highlights the influence of COVID-19 on wastes generated by plastic products along with environmental challenges and repercussions. Also, measures to combat the plastic pollution problem have to be implemented for future protection and safety of the environment.

A comprehensive and critical review on key elements to implement enzymatic PET depolymerization for recycling purposes

Plastics production and recycling chains must be refitted to a circular economy. Poly(ethylene terephthalate) (PET) is especially suitable for recycling because of its hydrolysable ester bonds and high environmental impact due to employment in single-use packaging, so that recycling processes utilizing enzymes are a promising biotechnological route to monomer recovery. However, enzymatic PET depolymerization still faces challenges to become a competitive route at an industrial level. In this review, PET characteristics as a substrate for enzymes are discussed, as well as the analytical methods used to evaluate the reaction progress. A comprehensive view on the biocatalysts used is discussed. Subsequently, different strategies pursued to improve enzymatic PET depolymerization are presented, including enzyme modification through mutagenesis, utilization of multiple enzymes, improvement of the interaction between enzymes and the hydrophobic surface of PET, and various reaction conditions (e.g., particle size, reaction medium, agitation, and additives). All scientific developments regarding these different aspects of PET depolymerization are crucial to offer a scalable and competitive technology. However, they must be integrated into global processes from upstream to downstream, discussed here at the final sections, which must be evaluated for their economic feasibility and life cycle assessment to check if PET recycling chains can be broadly incorporated into the future circular economy.

Ecotoxicological and physiological risks of microplastics on fish and their possible mitigation measures

Microplastics (MPs) are widely distributed and extensively found within marine ecosystems, and approximately 8 million tons of plastics are being dumped into the sea annually. Once reached the marine environment, plastics tend to get fragmented into smaller particles through photo-degradation, mechanical and biological processes. These MPs have raised concerns globally due to their potential toxic impacts on a wide variety of aquatic fauna and humans. Ingested microplastics can cause severe health implications in fishes, including reduced feeding intensity, improper gill functioning, immuno-suppression, and compromised reproducibility. Several studies were also conducted to scrutinize MPs trophic transfer through the food chain from primary producers to top predators and their bioaccumulation. This paper briefly summarizes all the possible sources, routes, bioavailability, trophic transfer, and consequences of microplastics in fishes. The review article also intended to highlight various mitigation strategies like implementing Four R's concept (refuse, reduce, reuse, and recycle), integrated strategies, ban on single-use plastics, use bioplastics, and create behavioural changes with public awareness.

A One Health perspective of the impacts of microplastics on animal, human and environmental health

Microplastics contamination is widespread in the environment leading to the exposure of both humans and other biota. While most studies overemphasize direct toxicity of microplastics, particle concentrations, characteristics and exposure conditions being used in these assays needs to be taken into consideration. For instance, toxicity assays that use concentrations over 100,000 times higher than those expected in the environment have limited practical relevance. Thus, adverse effects on animal and human health of current environmental concentrations are identified as a knowledge gap. Conversely, this does not suggest the lack of any significant effects of microplastics on a global scale. The One Health approach provides a novel perspective focused on the intersection of different areas, namely animal, human, and environmental health. This review provides a One Health transdisciplinary approach to microplastics, addressing indirect effects beyond simple toxicological effects. Microplastics can, theoretically, change the abiotic properties of matrices (e.g., soil permeability) and interfere with essential ecosystem functions affecting ecosystem services (e.g., biogeochemical processes) that can in turn impact human health. The gathered information suggests that more research is needed to clarify direct and indirect effects of microplastics on One Health under environmentally relevant conditions, presenting detailed knowledge gaps.

Assessing threats, regulations, and strategies to abate plastic pollution in LAC beaches during COVID-19 pandemic

Plastic use and production have dramatically increased globally over the past 65 years with the improvement of life quality by the daily use of plastic products. Still, around 50% of the plastic produced is disposable products that generate substantial waste. Several reports pointed out the adverse effects of plastic litter in coastal environments in recent years, emphasizing single-use plastics (SUP). In this manner, Latin America and the Caribbean (LAC) coastal environments are highly vulnerable due to wastewater treatment facilities scarcity and poor plastic waste management strategies. Since COVID-19 pandemic, the single-use plastic waste/person rate is expected to rise due to the use of personal protective equipment and SUP as health care measures. Based on literature research and the review of plastic waste regulations, this paper will assess the main COVID-19 plastic pollution threats and LAC beaches' regulations to suggest possible measures to abate this problem. The main findings suggest that unifying the ongoing fragmented and overlapped policies is key to abate plastic pollution, including plastic industry regulations and circular economies. In addition, increasing public risk perception about plastic pollution is critical to reducing plastic waste generation. Research advances in the adverse effects of plastic debris could improve the public's perception of plastic pollution risk, pushing forward global marine plastic governance.

Outcomes and Cost Evaluation Related to a Single-Use, Disposable Ureteric Stent Removal System: a Systematic Review of the Literature

PURPOSE OF REVIEW

To present the latest evidence related to the outcomes and cost of single-use, disposable ureteric stent removal system (Isiris).

RECENT FINDINGS

Our review suggests that compared to a reusable flexible cystoscope (re-FC), a disposable flexible cystoscope (d-FC) with built-in grasper (Isiris) significantly reduced procedural time and provided a cost benefit when the latter was used in a ward or outpatient clinic-based setting. The use of d-FC also allowed endoscopy slots to be used for other urgent diagnostic procedures. Disposable FCs are effective and safe for ureteric stent removal. They offer greater flexibility and, in most cases, have been demonstrated to be cost-effective compared to re-FCs. They are at their most useful in remote, low-volume centres, in less well-developed countries and in centres where large demand is placed on endoscopy resources.

Ocean plastics: environmental implications and potential routes for mitigation - a perspective

This review provides a current summary of the major sources and distribution of ocean plastic contamination, their potential environmental effects, and prospects towards the mitigation of plastic pollution. A characterization between micro and macro plastics has been established, along with a comprehensive discussion of the most common plastic waste sources that end up in aquatic environments within these categories. Distribution of these sources stems mainly from improper waste management, road runoff, and wastewater pathways, along with potential routes of prevention. The environmental impact of ocean plastics is not yet fully understood, and as such, current research on the potential adverse health effects and impact on marine habitats has been discussed. With increasing environmental damage and economic losses estimated at $US 1.5 trillion, the challenge of ocean plastics needs to be at the forefront of political and societal discussions. Efforts to increase the feasibility of collected ocean plastics through value-added commercial products and development of an international supply chain has been explored. An integrative, global approach towards addressing the growing ocean plastic problem has been presented.

Strategies for Poly(3-hydroxybutyrate) Production Using a Cold-Shock Promoter in Escherichia coli

The present study attempted to increase poly(3-hydroxybutyrate) (PHB) production by improving expression of PHB biosynthesis operon derived from Cupriavidus necator strain A-04 using various types of promoters. The intact PHB biosynthesis operon of C. necator A-04, an alkaline tolerant strain isolated in Thailand with a high degree of 16S rRNA sequence similarity with C. necator H16, was subcloned into pGEX-6P-1, pColdI, pColdTF, pBAD/Thio-TOPO, and pUC19 (native promoter) and transformed into Escherichia coli JM109. While the phaC_A–04 gene was insoluble in most expression systems tested, it became soluble when it was expressed as a fusion protein with trigger factor (TF), a ribosome associated bacterial chaperone, under the control of a cold shock promoter. Careful optimization indicates that the cold-shock cspA promoter enhanced phaC_A–04 protein expression and the chaperone function of TF play critical roles in increasing soluble phaC_A–04 protein. Induction strategies and parameters in flask experiments were optimized to obtain high expression of soluble PhaC_A–04 protein with high Y_P/S and PHB productivity. Soluble phaC_A–04 was purified through immobilized metal affinity chromatography (IMAC). The results demonstrated that the soluble phaC_A–04 from pColdTF-phaCAB_A–04 was expressed at a level of as high as 47.4 ± 2.4% of total protein and pColdTF-phaCAB_A–04 enhanced soluble protein formation to approximately 3.09−4.1 times higher than that from pColdI-phaCAB_A–04 by both conventional method and short induction method developed in this study. Cultivation in a 5-L fermenter led to PHB production of 89.8 ± 2.3% PHB content, a Y_P/S value of 0.38 g PHB/g glucose and a productivity of 0.43 g PHB/(L.h) using pColdTF-phaCAB_A–04. The PHB film exhibited high optical transparency and possessed M_w 5.79 × 10⁵ Da, M_n 1.86 × 10⁵ Da, and PDI 3.11 with normal melting temperature and mechanical properties.

Energy budget and carbon footprint in a wheat and maize system under ridge furrow strategy in dry semi humid areas

The well-irrigated planting strategy (WI) consumes a large amount of energy and exacerbates greenhouse gas emissions, endangering the sustainable agricultural production. This 2-year work aims to estimate the economic benefit, energy budget and carbon footprint of a wheat–maize double cropping system under conventional rain-fed flat planting (irrigation once a year, control), ridge–furrows with plastic film mulching on the ridge (irrigation once a year, RP), and the WI in dry semi-humid areas of China. Significantly higher wheat and maize yields and net returns were achieved under RP than those under the control, while a visible reduction was found for wheat yields when compared with the WI. The ratio of benefit: cost under RP was also higher by 10.5% than that under the control in the first rotation cycle, but did not differ with those under WI. The net energy output and carbon output followed the same trends with net returns, but the RP had the largest energy use efficiency, energy productivity carbon efficiency and carbon sustainability among treatments. Therefore, the RP was an effective substitution for well–irrigated planting strategy for achieving sustained agricultural development in dry semi-humid areas.