A concept for the biotechnological minimizing of emerging plastics, micro- and nano-plastics pollutants from the environment: A review

Polystyrene nanoplastics: optimized removal using magnetic nano-adsorbent and toxicity assessment in zebrafish embryos

Purpose

The presence of microplastics (MPs) and nanoplastics (NPs) in aquatic ecosystems has raised serious environmental and health concerns. Polystyrene is one of the most abundant plastic polymers found in the environment. Polystyrene MPs/NPs have harmful implications for human health and their removal from the environment has become a serious challenge.

Methods

In this study, we investigated the adsorptive uptake of polystyrene nanoplastics (PS NPs) from aqueous solutions using fly ash-loaded magnetic nanoparticles (FAMNPs) as the magnetic nano-adsorbent. During the factor screening study, the adsorption process was studied as a function of four variables namely pH (5-10), adsorption time (30-120 min), amount of FAMNPs (0.01-0.04 g), and stirring speed (50-200 rpm). Central composite design (CCD) and response surface methodology (RSM) were employed to establish the relationship between the variables. Furthermore, toxicity assessments of PS NPs were checked on a zebrafish model, shedding light on its potential ecological effects.

Results

Two variables namely the pH and amount of FAMNPs significantly influenced the adsorption capacity of FAMNPs and were further optimized for subsequent analysis. The optimum operational readings proposed by the model were pH (8.5), and the amount of FAMNPs (0.03 g), resulting in a good adsorption capacity of 29.12 mg/g for PS NPs. The adequacy of the proposed model was evaluated by analysis of variance (ANOVA). Zebrafish embryos exposed to PS NPs revealed physical deformations such as pericardial edema and malformed notochord.

Conclusion

The study demonstrates the effectiveness of FAMNPs in the adsorption of PS NPs from aqueous solutions, with optimal conditions identified at pH 8.5 and 0.03 g of FAMNPs using RSM. The adequacy of the model was confirmed through ANOVA analysis. Toxicity assessments on zebrafish embryos exposed to PS NPs revealed significant mortality and physical deformations, highlighting the importance of PS NPs removal for environmental health.

Graphical Abstract

The combined effects of polystyrene nanoplastics and dissolved organic matter on the environmental bioavailability of carbamazepine

The bioavailability of active pharmaceutical ingredients (APIs) plays a crucial role in determining the toxicity and risk of contaminants in the environment. However, the bioavailability of APIs in complex environmental matrices is still unclear. In this study, the combined effects of polystyrene nanoplastics (PS NPs) with various particle sizes (50, 100, and 1000 nm) and fulvic acid (FA) on the bioavailability of carbamazepine (CBZ) were investigated via negligible depletion solid-phase microextraction (nd-SPME) and Daphnia magna (D. magna) accumulation. The uptake kinetic study revealed that both PS NPs and FA reduced the elimination rate (k2) in most cases. The availability of CBZ to nd-SPME was determined by the hydrodynamic particle size of PS NPs, whereas the bioavailability to D. magna depended on the intrinsic particle size. The CBZ bioavailability was greater in co-exposed matrices due to the attenuated sorption of PS NPs to CBZ by FA modification. Notably, co-exposure of PS NPs and FA resulted in a higher bioaccumulation factor (BAF) of CBZ, probably due to the desorption and reabsorption of particle-associated CBZ. This study demonstrated that both PS NP particle size and FA binding affect the bioavailability of CBZ, and nd-SPME can mimic only the bioaccumulation of CBZ via diffusion.

Micro and nanoplastics pollution: Sources, distribution, uptake in plants, toxicological effects, and innovative remediation strategies for environmental sustainability

Microplastics and nanoplastics (MNPs), are minute particles resulting from plastic fragmentation, have raised concerns due to their widespread presence in the environment. This study investigates sources and distribution of MNPs and their impact on plants, elucidating the intricate mechanisms of toxicity. Through a comprehensive analysis, it reveals that these tiny plastic particles infiltrate plant tissues, disrupting vital physiological processes. Micro and nanoplastics impair root development, hinder water and nutrient uptake, photosynthesis, and induce oxidative stress and cyto-genotoxicity leading to stunted growth and diminished crop yields. Moreover, they interfere with plant-microbe interactions essential for nutrient cycling and soil health. The research also explores the translocation of these particles within plants, raising concerns about their potential entry into the food chain and subsequent human health risks. The study underscores the urgency of understanding MNPs toxicity on plants, emphasizing the need for innovative remediation strategies such as bioremediation by algae, fungi, bacteria, and plants and eco-friendly plastic alternatives. Addressing this issue is pivotal not only for environmental conservation but also for ensuring sustainable agriculture and global food security in the face of escalating plastic pollution.

A review on bio-based polymer polylactic acid potential on sustainable food packaging

Poly(lactic acid) (PLA) stands as a compelling alternative to conventional plastic-based packaging, signifying a notable shift toward sustainable material utilization. This comprehensive analysis illuminates the manifold applications of PLA composites within the realm of the food industry, emphasizing its pivotal role in food packaging and preservation. Noteworthy attributes of PLA composites with phenolic active compounds (phenolic acid and aldehyde, terpenes, carotenoid, and so on) include robust antimicrobial and antioxidant properties, significantly enhancing its capability to bolster adherence to stringent food safety standards. The incorporation of microbial and synthetic biopolymers, polysaccharides, oligosaccharides, oils, proteins and peptides to PLA in packaging solutions arises from its inherent non-toxicity and outstanding mechanical as well as thermal resilience. Functioning as a proficient film producer, PLA constructs an ideal preservation environment by merging optical and permeability traits. Esteemed as a pioneer in environmentally mindful packaging, PLA diminishes ecological footprints owing to its innate biodegradability. Primarily, the adoption of PLA extends the shelf life of products and encourages an eco-centric approach, marking a significant stride toward the food industry's embrace of sustainable packaging methodologies.

Graphical abstract

Nano Revolution: "Tiny tech, big impact: How nanotechnology is driving SDGs progress"

Nanotechnology has emerged as a powerful tool in addressing global challenges and advancing sustainable development. By manipulating materials at the nanoscale, researchers have unlocked new possibilities in various fields, including energy, healthcare, agriculture, construction, transportation, and environmental conservation. This paper explores the potential of nanotechnology and nanostructures in contributing to the achievement of the United Nations (UN) Sustainable Development Goals (SDGs) by improving energy efficiency and energy conversion, leading to a more sustainable and clean energy future, improving water purification processes, enabling access to clean drinking water for communities, enabling targeted drug delivery systems, early disease detection, and personalized medicine, thus revolutionizing healthcare, improving crop yields, efficient nutrient delivery systems, pest control mechanisms, and many other areas, therefore addressing food security issues. It also highlights the potential of nanomaterials in environmental remediation and pollution control. Therefore, by understanding and harnessing nanotechnology's potential, policymakers, researchers, and stakeholders can work together toward a more sustainable future by achieving the 17 UN SDGs.

Current Concerns about Microplastics and Nanoplastics: A Brief Overview

The widespread and increasing use of plastic-based goods in the present-day world has been raising many concerns about the formation of microplastics, their release, their impacts on the environment and, ultimately, on living organisms. These concerns are even greater regarding nanoplastics, i.e., nanosized microplastics, which may have even greater impacts. In this brief review, although without any claim or intention to exhaustively cover all the aspects of such a complex and many-sided issue, the very topical problem of the formation of microplastics, and the even more worrisome nanoplastics, from polymer-based products was considered. The approach is focused on a terse, straightforward, and easily accessible analysis oriented to the main technological engineering aspects regarding the sources of microplastics and nanoplastics released into the environment, their nature, some of the consequences arising from the release, the different polymers involved, their technological form (i.e., products or processes, with particular attention towards unintentional release), the formation mechanisms, and some possible mitigation pathways.

Nanoplastic toxicity induces metabolic shifts in Populus × euramericana cv. '74/76' revealed by multi-omics analysis

There is increasing global concern regarding the pervasive issue of plastic pollution. We investigated the response of Populus × euramericana cv. '74/76' to nanoplastic toxicity via phenotypic, microanatomical, physiological, transcriptomic, and metabolomic approaches. Polystyrene nanoplastics (PS-NPs) were distributed throughout the test plants after the application of PS-NPs. Nanoplastics principally accumulated in the roots; minimal fractions were translocated to the leaves. In leaves, however, PS-NPs easily penetrated membranes and became concentrated in chloroplasts, causing thylakoid disintegration and chlorophyll degradation. Finally, oxidant damage from the influx of PS-NPs led to diminished photosynthesis, stunted growth, and etiolation and/or wilting. By integrating dual-omics data, we found that plants could counteract mild PS-NP-induced oxidative stress through the antioxidant enzyme system without initiating secondary metabolic defense mechanisms. In contrast, severe PS-NP treatments promoted a shift in metabolic pattern from primary metabolism to secondary metabolic defense mechanisms, an effect that was particularly pronounced during the upregulation of flavonoid biosynthesis. Our findings provide a useful framework from which to further clarify the roles of key biochemical pathways in plant responses to nanoplastic toxicity. Our work also supports the development of effective strategies to mitigate the environmental risks of nanoplastics by biologically immobilizing them in contaminated lands.

Are you drowned in microplastic pollution? A brief insight on the current knowledge for early career researchers developing novel remediation strategies

Microplastics (MPs) composed of different polymers with various shapes, within a vast granulometric distribution (1 μm - 5 mm) and with a wide variety of physicochemical surface and bulk characteristics spiral around the globe, with different atmospheric, oceanic, cryospheric, and terrestrial residence times, while interacting with other pollutants and biota. The challenges of microplastic pollution are related to the complex relationships between the microplastic generation mechanisms (physical, chemical, and biological), their physicochemical properties, their interactions with other pollutants and microorganisms, the changes in their properties with aging, and their small sizes that facilitate their diffusion and transportation between the air, water, land, and biota, thereby promoting their ubiquity. Early career researchers (ERCs) constitute an essential part of the scientific community committed to overcoming the challenges of microplastic pollution with their new ideas and innovative scientific perspectives for the development of remediation technologies. However, because of the enormous amount of scientific information available, it may be difficult for ERCs to determine the complexity of this environmental issue. This mini-review aims to provide a quick and updated overview of the essential insights of microplastic pollution to ERCs to help them acquire the background needed to develop highly innovative physical, chemical, and biological remediation technologies, as well as valorization proposals and environmental education and awareness campaigns. Moreover, the recommendations for the development of holistic microplastic pollution remediation strategies presented here can help ERCs propose technologies considering the environmental, social, and practical dimensions of microplastic pollution while fulfilling the current government policies to manage this plastic waste.

Microplastic separation and enrichment in microchannels under derivative electric field gradient by bipolar electrode reactions

The decomposed plastic products in the natural environment evolve into tiny plastic particles with characteristics such as small size, lightweight, and difficulty in removal, resulting in a significant pollution issue in aquatic environments. Significant progress has been made in microplastic separation technology benefiting from microfluidic chips in recent years. Based on the mechanisms of microfluidic control technology, this study investigates the enrichment and separation mechanisms of polystyrene particles in an unbuffered solution. The Faraday reaction caused by the bipolar electrodes changes the electric field gradient and improves the separation efficiency. We also propose  an evaluation scheme to measure the separation efficiency. Finite element simulations are conducted to parametrically analyze the influence of applied voltages, channel geometry, and size of electrodes on plastic particle separation. The numerical cases indicate that the electrode-installed microfluidic channels separate microplastic particles effectively and precisely. The electrodes play an important role in local electric field distribution and trigger violent chemical reactions. By optimizing the microchannel structure, applied voltages, and separation channel angle, an optimal solution for separating microplastic particles can be found. This study could supply some references to control microplastic pollution in the future.

Effects of nanoplastics on the gut microbiota of Pacific white shrimp Litopenaeus vannamei

Nanoplastics (NPs) are an abundant, long-lasting, and widespread type of environmental pollution that is of increasing concern because of the serious threats they might pose to ecosystems and species. Identifying the ecological effects of plastic pollution requires understanding the effects of NPs on aquatic organisms. Here, we used the Pacific white shrimp (Litopenaeus vannamei) as a model species to investigate whether ingestion of polystyrene NPs affects gut microbes and leads to metabolic changes in L. vannamei. The abundance of Proteobacteria increased and that of Bacteroidota decreased after NPs treatment. Specifically, Vibrio spp., photobacterium spp., Xanthomarina spp., and Acinetobacter spp. increased in abundance, whereas Sulfitobacter spp. and Pseudoalteromonas spp. decreased. Histological observations showed that L. vannamei exposed to NP displayed a significantly lower intestinal fold height and damaged intestinal structures compared with the control group. Exposure to NPs also stimulated alkaline phosphatase, lysozyme, and acid phosphatase activity, resulting in an immune response in L. vannamei. In addition, the content of triglycerides, total cholesterol, and glucose were significantly altered after NP exposure. These results provided significant ecotoxicological data that can be used to better understand the biological fate and effects of NPs in L. vannamei.

Towards a Sustainable Future: Advancing an Integrated Approach for the Recycling and Valorization of Agricultural Plastics

Plastic pollution has become a pressing environmental issue. The agricultural sector, in particular, is a significant contributor to this problem, given the widespread use of plastics in farming practices and a lack of and/or use of inefficient approaches for the recycling and valorization of agricultural plastic waste. This has resulted in the accumulation of these residues in landfills and/or their improper disposal, which has exacerbated their environmental impact, leading to negative consequences on soil, water, and ecosystems. This work provides an overview on the current methodologies available to address the challenges associated with inadequate management of agricultural plastics and highlights the need for a comprehensive and systematic methodology, involving material development, polymer processing, waste collection, sorting, and valorization. It emphasizes the importance of collaboration between polymer producers, polymer manufacturers, farmers, policymakers, waste management companies, and recyclers to develop effective, technical, and economically viable recycling and valorization schemes. This paper addresses gaps and provides guidance on possible solutions, specifically polymer development, policy instruments, regulatory frameworks, collection schemes, and the technical approaches required for the adequate valorization of agricultural plastic waste. Furthermore, it highlights the associated barriers and benefits of the different presented approaches. It also aims to promote awareness on agricultural plastic waste and provide guidance on the best approaches to reduce its environmental impact.

Sodium nitroprusside alleviates nanoplastics-induced developmental toxicity by suppressing apoptosis, ferroptosis and inflammation

The health damage caused by nanoplastics (NPs) pollution has become one of the global scientific problems to be solved urgently. However, the toxicological mechanism of NPs is complex, and the research progress of anti-toxicity is limited. Thus, it has potential application value to explore or develop drugs that can effectively alleviate or remove NPs with biological toxicity. In this research, 8 μM sodium nitroprusside (SNP) solution was used to treat zebrafish larvae with 20 mg/L NPs for up to 12 days, and the results showed that SNP treatments were effective in alleviating NPs-caused developmental toxicity in zebrafish larvae. Further examination of its signaling pathway revealed that NPs-induced oxidative stress was mitigated by activating the NO-sGC-cGMP signaling pathway and reduced most of the reactive oxygen species (ROS). Subsequently, we detected the key substances and the key enzymes involved in apoptosis and ferroptosis, and found that oxidative stress-induced mitochondria-dependent apoptosis and lipid peroxidation-caused ferroptosis were alleviated. Finally, observed the accumulation of NPs and ROS in the liver of zebrafish larvae, which is the target organ of immunotoxicity, and we found that SNP could alleviate NPs-caused inflammation by analyzing the fluorescence intensity of neutrophils and macrophages in transgenic zebrafish and detecting the expression of key immune genes. In conclusion, this research has shown for the first time that SNP treatment can significantly inhibit NPs-induced developmental toxicity, resulting from oxidative stress-induced apoptosis, ferroptosis and inflammation in zebrafish larvae.

Characterization and Antibacterial Properties of Egg White Protein Films Loaded with ε-Polylysine: Evaluation of Their Degradability and Application

There is an ongoing trend to design new kinds of food packaging materials with excellent properties which are environmentally friendly enough. The aim of this study was to prepare and characterize egg white protein (EWP)-based composite films with and without ε-polylysine (Lys), as well as to compare their physical-chemical properties, structural properties, degradation and antibacterial properties. The results showed that with the addition of Lys, the composite films showed a decreasing tendency of the water permeability due to the enhanced interaction between proteins and water molecules. As indicated by the structural properties, stronger cross-linking and intermolecular interactions happened with increasing concentration of Lys. In addition, the composite films presented excellent antibacterial activities against Escherichia coli and Staphylococcus aureus on chilled pork in the presence of Lys. Therefore, our prepared films might be used as a freshness-keeping material with an application in meat preservation. The biodegradation evaluation demonstrated that the composite films were environmental-friendly and have potential applications in the field of food packaging.

Current approaches, and challenges on identification, remediation and potential risks of emerging plastic contaminants: A review

Plastics are widely employed in modern civilization because of their durability, mold ability, and light weight. In the recent decade, micro/nanoplastics research has steadily increased, highlighting its relevance. However, contaminating micro/nanoplastics in marine environments, terrestrial ecosystems, and biological organisms is considered a severe threat to the environmental system. Geographical distribution, migration patterns, etymologies of formation, and ecological ramifications of absorption are just a few topics covered in the scientific literature on environmental issues. Degradable solutions from material science and chemistry are needed to address the micro/nanoplastics problem, primarily to reduce the production of these pollutants and their potential effects. Removing micro/nanoplastics from their discharge points has been a central and effective way to mitigate the adverse pollution effects. In this review, we begin by discussing the hazardous effect on living beings and the identification-characterization of micro/nanoplastics. Then, we provide a summary of the existing degradation strategies, which include bio-degradation and advanced oxidation processes (AOPs), and a detailed discussion of their degradation mechanisms is also represented. Finally, a persuasive summary of the evaluated work and projections for the future of this topic is provided.

Exposure to polystyrene nanoparticles at predicted environmental concentrations enhances toxic effects of Acinetobacter johnsonii AC15 infection on Caenorhabditis elegans

Nanoplastics and microbial pathogens are both widely distributed in the environment; however, their combined toxicity remains largely unclear. Using Caenorhabditis elegans as an animal model, we examined the possible effect of exposure to polystyrene nanoparticle (PS-NP) in Acinetobacter johnsonii AC15 (a bacterial pathogen) infected animals. Exposure to PS-NP at the concentrations of 0.1-10 μg/L significantly enhanced the toxicity of Acinetobacter johnsonii AC15 infection on lifespan and locomotion behaviors. In addition, after exposure to 0.1-10 μg/L PS-NP, the accumulation of Acinetobacter johnsonii AC15 in body of nematodes was also increased. Meanwhile, the innate immune response indicated by the increase of antimicrobial gene expressions in Acinetobacter johnsonii AC15 infected nematodes was suppressed by exposure to 0.1-10 μg/L PS-NP. Moreover, expressions of egl-1, dbl-1, bar-1, daf-16, pmk-1, and elt-2 governing the bacterial infection and immunity in Acinetobacter johnsonii AC15 infected nematodes were further inhibited by exposure to 0.1-10 μg/L PS-NP. Therefore, our data suggested the possible exposure risk of nanoplastic at predicted environmental concentrations in enhancing the toxic effects of bacterial pathogens on environmental organisms.

Modification of fluorescence staining method for small-sized microplastic quantification: Focus on the interference exclusion and exposure time optimization

Microplastics are an emerging pollutant of global concern, and fluorescence staining as an efficient method for small-sized microplastic qualification often undergoes the serious interference from external environments. The key steps affecting the accuracy of fluorescent staining and the corresponding quality assurance measures were rarely known. Therefore, this study took the Nile Red/DAPI co-staining method as an example to explore the key factors affecting its accuracy and effective measures to avoid interference. High background microplastic contamination in typical lab waters (up to 1115 MP/L), glass fiber filter membrane and glassware were identified as dominant factors affecting microplastic quantification. The background microplastics in lab waters mainly originated from the process of water production and storage. A simple filtration process removed 99% of the background microplastic in the lab waters. After burning at 500 °C for 1 h, the microplastic contamination in the filter membrane and glassware was completely eliminated. H₂O₂ pretreatment and exposure time caused erroneous microplastic size assessment, and were suggested to be set at 48 h and 10 ms, respectively. During the extraction process, the residue in beakers reached ~ 20% and > 50% for 5 μm and 20 μm sized microplastics, respectively, greatly contributing to the microplastic loss. The comprehensive modified measures caused microplastic concentrations in the three typical samples detected by Nile Red/DAPI co-staining method to decrease by 65.7 - 92.2% and to approach the micro-Raman results. This study clarified the reasons for interfering with quantitative microplastics by fluorescent staining and the effective measures to avoid interference, which were conducive to improving the accuracy of quantitative methods of microplastics.