Micro and nanoplastics ravaging our agroecosystem: A review of occurrence, fate, ecological impacts, detection, remediation, and prospects

Toxicological assays and metabolomic profiling to evaluate the effects of virgin and aged micro- and nano- polystyrene plastics in SH-SY5Y human neuroblastoma cells

In the contemporary era, named plasticene, the extensive presence of micro- and nanoplastics (MPs/NPs) in all environmental matrices constitutes a global challenge that impacts on living beings, including humans. Regardless of the route of exposure, the internalized MPs/NPs may reach the central nervous system and cause cytotoxicity. The effects of nano- and micro- polystyrene particles (n/mPS; 100 μg/mL), both in virgin (v) and home oxidized (ox) form, were assessed on the human neuroblastoma cells SH-SY5Y, treated for 24 h, using toxicological endpoints and 1H NMR-based metabolomics. A pro-oxidant effect was shown by reactive oxygen species (ROS) overproduction, present in virgin and oxidized particles, albeit 27.6 % and 29.5 % higher in ox-nPS and ox-mPS. DNA damage, mitochondrial impairment, and lipid peroxidation were found to be directly related to particle size and oxidation state (v-nPS < ox-nPS < v-mPS < ox-mPS). The metabolic changes induced by v- and ox- n/mPS in neuroblastoma cells involved the amino acid and energy metabolism, osmoregulation, oxidative stress, and neurotransmission. Interestingly, it was highlighted the ability of SH-SY5Y cells exposed to ox-nPS to counteract more effectively oxidative damage by reshaping metabolic pathways. Overall, the combination of toxicological assays and metabolic profiling confirmed the harmful effects induced by n/mPS to SH-SY5Y cells, always enhanced by the in home-oxidized counterpart, that led to cytotoxic effects and changes in cell metabolism. Despite a variable capacity for cellular homeostasis, the results shed light on the potential risks that these ubiquitous xenobiotics pose to human health, acting also as "triggers" for neurodegenerative diseases.

Strategies for the Remediation of Micro- and Nanoplastics from Contaminated Food and Water: Advancements and Challenges

Micro- and nanoplastic (MNP) pollution is a significant concern for ecosystems worldwide. The continuous generation and extensive utilization of synthetic plastics have led to the widespread contamination of water and food resources with MNPs. These pollutants originate from daily-use products and industrial waste. Remediation of such pollutants is essential to protect ecosystems and human health since these ubiquitous contaminants pose serious biological and environmental hazards by contaminating food chains, water sources, and the air. Various remediation techniques, including physical, chemical, sophisticated filtration, microbial bioremediation, and adsorption employing novel materials, provide encouraging avenues for tackling this worldwide issue. The biotechnological approaches stand out as effective, eco-friendly, and sustainable solutions for managing these toxic pollutants. However, the complexity of MNP pollution presents significant challenges in its management and regulation. Addressing these challenges requires cross-disciplinary research efforts to develop and implement more efficient, sustainable, eco-friendly, and scalable techniques for mitigating widespread MNP pollution. This review explores the various sources of micro- and nanoplastic contamination in water and food resources, their toxic impacts, remediation strategies-including advanced biotechnological approaches-and the challenges in treating these pollutants to alleviate their effects on ecosystems and human health.

Exploring biodegradable alternatives: microorganism-mediated plastic degradation and environmental policies for sustainable plastic management

Plastics offer versatility, durability and low production costs, but they also pose environmental and health risks due to improper disposal, accumulation in water bodies, low recycling rates and temporal action that causes physicochemical changes in plastics and the release of toxic products to animal health and nature. Some microorganisms may play crucial roles in improving plastic waste management in the future. Cunningamella echinulata has been identified as a promising candidate that remains viable for long periods and produces a cutinase that is capable of degrading plastic. Other recent approaches involving the use of microorganisms are discussed in this review. However, there does not seem to be a single science that is efficient or most appropriate for solving the problem of plastic pollution on the planet at present. Regulations, especially the implementation of different laws that address the entire plastic cycle in different countries, such as Brazil, the USA, China and the European Union, play important roles in the management of this waste and can contribute to reducing this problem. In the context of the transversality of the information compiled here, the current limitations are discussed, and an effective plan is proposed to reduce plastic pollution. Although it is challenging, it involves implementing legislation, promoting sustainable alternatives, improving collection and recycling systems, encouraging reuse, supporting research and technological innovation, promoting corporate responsibility, collaborating globally, raising public awareness, optimizing waste management and, above all, continuously monitoring the progress of actions based on measurable metrics.

Ecological consequences of antimicrobial residues and bioactive chemicals on antimicrobial resistance in agroecosystems

BACKGROUND

The widespread use of antimicrobials in agriculture, coupled with bioactive chemicals like pesticides and growth-promoting agents, has accelerated the global crisis of antimicrobial resistance (AMR). Agroecosystems provides a platform in the evolution and dissemination of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs), which pose significant threats to both environmental and public health.

AIM OF REVIEW

This review explores the ecological consequences of antimicrobial residues and bioactive chemicals in agroecosystems, with a focus on their role in shaping AMR. It delves into the mechanisms by which these substances enter agricultural environments, their interactions with soil microbiomes, and the subsequent impacts on microbial community structure.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Evidence indicates that the accumulation of antimicrobials promotes resistance gene transfer among microorganisms, potentially compromising ecosystem health and agricultural productivity. By synthesizing current research, we identify critical gaps in knowledge and propose strategies for mitigating the ecological risks associated with antimicrobial residues. Moreover, this review highlights the urgent need for integrated management approaches to preserve ecosystem health and combat the spread of AMR in agricultural settings.

A review of the ecotoxicological status of microplastic pollution in African freshwater systems

Microplastics (MPs) have found extensive application globally due to their low cost, flexibility and light weight. Microplastic pollution is a growing environmental concern that poses significant threats to aquatic ecosystems worldwide, including African freshwater systems. Nevertheless, although Africa houses some of the deepest and largest freshwater rivers and lakes in the world such as Lake Tanganyika and Victoria, River Congo and the Nile, there is limited information available regarding the presence of MPs in these inland waters. Selected published data on MPs in African freshwater systems, including sediments, biota, rivers, and lakes, were incorporated in this review. The study discovered that the sampling technique employed has a major impact on the morphological characteristics and abundance of MPs in African freshwater systems. Fibers and fragments were the most common shapes; black, white, and transparent were the most prevalent colors; and polyethene terephthalate, polystyrene, and polypropylene were the frequently dominant polymers. As the distance between the sampling sites increased geographically, the polymer similarities declined. MPs have been found to translocate into body cells and tissues where they are capable of causing genetic mutations, cytotoxicity, oxidative stress and neurotoxicity. In Africa, MPs are poorly managed and monitored, and there has been insufficient research done on the possibility that they could be present in drinking water. Considering the fact that humans in the continent are exposed to freshwater and aquatic organisms, the risk assessment routes are currently unvalidated, therefore it was recommended that African nations should strengthen their capacity for plastic management and environmental monitoring. This review provides up to date information on the occurrence, prevalence, ecotoxicity and management of MPs across African freshwater systems.

Occurrence and ecotoxicological impacts of polybrominated diphenyl ethers (PBDEs) in electronic waste (e-waste) in Africa: Options for sustainable and eco-friendly management strategies

Polybrominated diphenyl ethers (PBDEs) are persistent contaminants used as flame retardants in electronic products. PBDEs are contaminants of concern due to leaching and recalcitrance conferred by the stable and hydrophobic bromide residues. The near absence of legislatures and conscious initiatives to tackle the challenges of PBDEs in Africa has allowed for the indiscriminate use and consequent environmental degradation. Presently, the incidence, ecotoxicity, and remediation of PBDEs in Africa are poorly elucidated. Here, we present a position on the level of contamination, ecotoxicity, and management strategies for PBDEs with regard to Africa. Our review shows that Africa is inundated with PBDEs from the proliferation of e-waste due to factors like the increasing growth in the IT sector worsened by the procurement of second-hand gadgets. An evaluation of the fate of PBDEs in the African environment reveals that the environment is adequately contaminated, although reported in only a few countries like Nigeria and Ghana. Ultrasound-assisted extraction, microwave-assisted extraction, and Soxhlet extraction coupled with specific chromatographic techniques are used in the detection and quantification of PBDEs. Enormous exposure pathways in humans were highlighted with health implications. In terms of the removal of PBDEs, we found a gap in efforts in this direction, as not much success has been reported in Africa. However, we outline eco-friendly methods used elsewhere, including microbial degradation, zerovalent iron, supercritical fluid, and reduce, reuse, recycle, and recovery methods. The need for Africa to make and implement legislatures against PBDEs holds the key to reduced effect on the continent.

Carbon Nanodot-Microbe-Plant Nexus in Agroecosystem and Antimicrobial Applications

The intensive applications of nanomaterials in the agroecosystem led to the creation of several environmental problems. More efforts are needed to discover new insights in the nanomaterial-microbe-plant nexus. This relationship has several dimensions, which may include the transport of nanomaterials to different plant organs, the nanotoxicity to soil microbes and plants, and different possible regulations. This review focuses on the challenges and prospects of the nanomaterial-microbe-plant nexus under agroecosystem conditions. The previous nano-forms were selected in this study because of the rare, published articles on such nanomaterials. Under the study's nexus, more insights on the carbon nanodot-microbe-plant nexus were discussed along with the role of the new frontier in nano-tellurium-microbe nexus. Transport of nanomaterials to different plant organs under possible applications, and translocation of these nanoparticles besides their expected nanotoxicity to soil microbes will be also reported in the current study. Nanotoxicity to soil microbes and plants was investigated by taking account of morpho-physiological, molecular, and biochemical concerns. This study highlights the regulations of nanotoxicity with a focus on risk and challenges at the ecological level and their risks to human health, along with the scientific and organizational levels. This study opens many windows in such studies nexus which are needed in the near future.

Effects of different sizes of microplastic particles on soil respiration, enzyme activities, microbial communities, and seed germination

Microplastics (MPs) are emerging pollutants of terrestrial ecosystems. The impacts of MP particle size on terrestrial systems remain unclear. The current study aimed to investigate the effects of six particle sizes (i.e., 4500, 1500, 500, 50, 5, and 0.5 μm) of polyethylene (PE) and polyvinyl chloride (PVC) on soil respiration, enzyme activity, bacteria, fungi, protists, and seed germination. MPs significantly promoted soil respiration, and the stimulating effects of PE were the strongest for medium and small-sized (0.5-1500 μm) particles, while those of PVC were the strongest for small particle sizes (0.5-50 μm). Large-sized (4500 μm) PE and all sizes of PVC significantly improved soil urease activity, while medium-sized (1500 μm) PVC significantly improved soil invertase activity. MPs altered the soil microbial community diversity, and the effects were especially pronounced for medium and small-sized (0.5-1500 μm) particles of PE and PVC on bacteria and fungi and small-sized (0.5 μm) particles of PE on protists. The impacts of MPs on bacteria and fungi were greater than on protists. The seed germination rate of Brassica chinensis decreased gradually with the decrease in PE MPs particle size. Therefore, to reduce the impact of MPs on soil ecosystems, effective measures should be taken to avoid the transformation of MPs into smaller particles in soil environmental management.

Emerging contaminants in food matrices: An overview of the occurrence, pathways, impacts and detection techniques of per- and polyfluoroalkyl substances

Per- and polyfluoroalkyl substances (PFAS) have been used in industrial and consumer applications for ages. The pervasive and persistent nature of PFAS in the environment is a universal concern due to public health risks. Experts acknowledge that exposure to high levels of certain PFAS have consequences, including reduced vaccine efficacy, elevated cholesterol, and increased risk of high blood pressure. While considerable research has been conducted to investigate the presence of PFAS in the environment, the pathways for human exposure through food and food packaging/contact materials (FCM) remain unclear. In this review, we present an exhaustive overview of dietary exposure pathways to PFAS. Also, the mechanism of PFAS migration from FCMs into food and the occurrence of PFAS in certain foods were considered. Further, we present the analytical techniques for PFAS in food and food matrices as well as exposure pathways and human health impacts. Further, recent regulatory actions working to set standards and guidelines for PFAS in food packaging materials were highlighted. Alternative materials being developed and evaluated for their safety and efficacy in food contact applications, offering promising alternatives to PFAS were also considered. Finally, we reported on general considerations and perspectives presently considered.

Association of tetrabromobisphenol A (TBBPA) with micro/nano-plastics: A review of recent findings on ecotoxicological and health impacts

Despite the diverse research into the environmental impact of plastics, several stones have yet to be unraveled in terms of their ecotoxicological potential. Moreover, their detrimental impacts have become terrifying in recent years as the understanding of their tendency to associate and form cohorts with other emerging contaminants grew. Despite the hypothesis that microplastics may potentially adsorb organic pollutants, sequestering and making them not bioavailable for enhanced toxicity, evidence with pollutants such as Tetrabromobisphenol A (TBBPA) defers this assertion. TBBPA, one of the most widely used brominated flame retardants, has been enlisted as an emerging contaminant of serious environmental and human health concerns. Being also an additive to plasticware, it is not far to suspect that TBBPA could be found in association with micro/nanoplastics in our environment. Several pieces of evidence from recent studies have confirmed the micro/nanoplastics-TBBPA association and have exposed their compounded detrimental impacts on the environment and human health. This study, therefore, presents a comprehensive and up-to-date review of recent findings regarding their occurrence, factors that foster their association, including their sorption kinetics and isotherms, and their impacts on aquatic/agroecosystem and human health. The way forward and prospects for future studies were presented. This research is believed to be of significant interest to the readership due to its relevance to current environmental challenges posed by plastics and TBBPA. The study not only contributes valuable insights into the specific interaction between micro/nanoplastics and TBBPA but also suggests the way forward and prospects for future studies in this field.

Impact of microplastic particle size on physiological and biochemical properties and rhizosphere metabolism of Zea mays L.: Comparison in different soil types

The effect of microplastics (MPs) on plant growth has received increasing attention. However, whether soil texture and MPs size influence the toxicological effects of MPs on plants is unknown. To address this knowledge gap, two soils with different physical structures (lime concretion black and silty loam soils) were selected to explore the potential toxicity of MPs of different particle sizes to maize growth. The results showed that, in both soils, the harm caused by small MPs on maize growth was greater than that caused by large MPs. Low MPs concentrations had no significant effect on maize growth between two soil types; however, when exposed to a concentration of 1 % large MPs, the dry biomass of maize was promoted in lime concretion black soil but inhibited in silty loam soil. All MPs-exposed treatments resulted in a high level of superoxide anions in maize roots, resulting in an increase in the root aerenchyma area and reducing the metabolic activity of maize roots. Metabolomics showed that MPs exposure affected multiple amino acid metabolic pathways, including phenylalanine and tyrosine metabolism, and inhibited lignin biosynthesis in roots. This study provides a theoretical basis for a more comprehensive assessment of the effect of MPs pollution on agricultural production.

A review of heavy metal risks around e-waste sites and comparable municipal dumpsites in major African cities: Recommendations and future perspectives

In Africa, the effects of informal e-waste recycling on the environment are escalating. It is regularly transported from developed to developing nations, where it is disassembled informally in search of precious metals, thus increasing human exposure to harmful compounds. Africa has a serious problem with e-waste, as there are significant facilities in Ghana and Nigeria where imported e-waste is unsafely dismantled. however, because they are in high demand and less expensive than new ones, old electronic and electrical items are imported in large quantities, just like in many developing nations. After that, these objects are frequently scavenged to recover important metals through heating, burning, incubation in acids, and other techniques. Serious health hazards are associated with these activities for workers and individuals close to recycling plants. At e-waste sites in Africa, there have been documented instances of elevated concentrations of hazardous elements, persistent organic pollutants, and heavy metals in dust, soils, and vegetation, including plants consumed as food. Individuals who handle and dispose of e-waste are exposed to highly hazardous chemical substances. This paper examines heavy metal risks around e-waste sites and comparable municipal dumpsites in major African cities. Elevated concentrations of these heavy metals metal in downstream aquatic and marine habitats have resulted in additional environmental impacts. These effects have been associated with unfavourable outcomes in marine ecosystems, such as reduced fish stocks characterized by smaller sizes, increased susceptibility to illness, and decreased population densities. The evidence from the examined studies shows how much e-waste affects human health and the environment in Africa. Sub-Saharan African nations require a regulatory framework that includes specialized laws, facilities, and procedures for the safe recycling and disposal of e-waste.

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.

Nano-microplastic and agro-ecosystems: a mini-review

Plastics' unavoidable and rampant usage causes their trash to be extensively dispersed in the atmosphere and land due to its numerous characteristics. Because of extensive plastic usage and increased manufacturing, there is insufficient recycling and a large accumulation of microplastics (MPs) in the environment. In addition to their wide availability in the soil and atmosphere, micro- and nanoplastics are becoming contaminants worldwide. Agro-ecosystem functioning and plant development are being negatively impacted in several ways by the contamination of the environment and farmland soils with MPs (<5 mm) and nanoplastics (<1 µm). The contributions of some recyclable organic waste and plastic film mulching and plastic particle deposition in agroecosystems may be substantial; therefore, it is crucial to understand any potentially hazardous or undesirable impacts of these pollutants on agroecosystems. The dissolution of bioplastics into micro- and nano-particles (MBPs and NBPs) has not been considered in recent studies, which focus primarily on agro-ecosystems. It is essential to properly understand the distribution, concentration, fate, and main source of MPs, NPS, MBPs, and NBPs in agroecosystems. Based on the limited findings, understanding the knowledge gap of environmental impact from micro and nanoplastic in farming systems does not equate to the absence of such evidence. It reveals the considerations for addressing the gaps to effectively protect global food safety and security in the near future.

Silicon-based nanoparticles for mitigating the effect of potentially toxic elements and plant stress in agroecosystems: A sustainable pathway towards food security

Due to their size, flexibility, biocompatibility, large surface area, and variable functionality nanoparticles have enormous industrial, agricultural, pharmaceutical and biotechnological applications. This has led to their widespread use in various fields. The advancement of knowledge in this field of research has altered our way of life from medicine to agriculture. One of the rungs of this revolution, which has somewhat reduced the harmful consequences, is nanotechnology. A helpful ingredient for plants, silicon (Si), is well-known for its preventive properties under adverse environmental conditions. Several studies have shown how biogenic silica helps plants recover from biotic and abiotic stressors. The majority of research have demonstrated the benefits of silicon-based nanoparticles (Si-NPs) for plant growth and development, particularly under stressful environments. In order to minimize the release of brine, heavy metals, and radioactive chemicals into water, remove metals, non-metals, and radioactive components, and purify water, silica has also been used in environmental remediation. Potentially toxic elements (PTEs) have become a huge threat to food security through their negative impact on agroecosystem. Si-NPs have the potentials to remove PTEs from agroecosystem and promote food security via the promotion of plant growth and development. In this review, we have outlined the various sources and ecotoxicological consequences of PTEs in agroecosystems. The potentials of Si-NPs in mitigating PTEs were extensively discussed and other applications of Si-NPs in agriculture to foster food security were also highlighted.