Strengthening citizen science partnerships with frontline sanitation personnel to study and tackle plastic pollution.

The COVID-19 outbreak has boosted demand for and use of personal protective equipment (PPE) and other single-use plastics, adding to the environment's already high levels of plastic pollution and endangering biota. Estimating the relative abundance of PPE wastes that end up in the environment is crucial and has remained a challenge for COVID-19 researchers. Citizen science has been utilized in recent studies to monitor and collect data using volunteers, and it has proven to be a valuable approach even in difficult situations. The expansion of citizen scientific participation groups is important in light of the growing anthropogenic impacts of plastic pollution. To date, frontline sanitary personnel are often overlooked and underutilized in a citizen science perspective, yet they serve critical roles in maintaining cleanliness in key environmental settings (e.g., beaches and streets) both during and beyond the pandemic. This paper explores and emphasizes the advantages and need of including frontline sanitary personnel into citizen science for the benefit of both researchers and communities, as well as to encourage long-term goals in global plastic litter monitoring, thereby exemplifying citizen science opportunities. Recommendations are made to design in order to improve the future status of citizen science development.

Comparative genome analysis of completely sequenced Cupriavidus genomes provides insights into the biosynthetic potential and versatile applications of Cupriavidus alkaliphilus ASC-732.

The genome analysis of microorganisms provides valuable information to endorse more extensive research on their potential applications. In this paper, the genome of Cupriavidus alkaliphilus ASC-732, isolated from agave rhizosphere in northeastern Mexico, was analyzed and compared with the genomes of other Cupriavidus species to gain better insight into the parts in the genetic makeup responsible for essential metabolic pathways and others of biotechnological importance. Here, the key genes related to glycolysis, pentose phosphate, and the Entner-Doudoroff and tricarboxylic acid cycle pathways were predicted. Comparative genome analysis revealed that the key genes for hydrogenotrophic growth and carbon fixation pathway, i.e., those coding for hydrogenase and enzymes Calvin-Benson-Bassham cycle, are absent in C. alkaliphilus ASC-732. Furthermore, capabilities for producing polyhydroxyalkanoates and extracellular polysaccharide matrix and degrading xenobiotics were found, and the related pathways are explained. Moreover, biofilm formation and the production of exopolysaccharides and polyhydroxyalkanoates were corroborated with crystal violet staining, calcofluor, and Nile red fluorochromes, confirming the presence of the products of the active genes in these pathways and their related metabolic routes, respectively. Additionally, a large group of genes essential for the resistance and detoxification of several heavy metals were also found. Thus, the present study demonstrates that this strain can respond to various environmental signals, such as energy source, nutrient limitations, virulence, and extreme metals concentration, indicating the possibility to foster C. alkaliphilus ASC-732 in diverse biotechnological applications.

Investigation on the Evolutionary Relation of Diverse Polyhydroxyalkanoate Gene Clusters in Betaproteobacteria.

Products of numerous genes (phaC, phaA, phaB, phaP, phaR, and phaZ) are involved in the synthesis and degradation processes of the ubiquitous prokaryotic polyhydroxyalkanoate (PHA) intracellular reserve storage system. In this study, we performed a bioinformatics analysis to identify PHA-related genes and proteins in the genome of 66 selected organisms (class: Betaproteobacteria) that occur in various habitats; besides, evolutionary trajectories of the PHA system are reported here. The identified PHA-related genes were organized into clusters, and the gene arrangement was highly diverse. The occurrence and distribution of PHA-related clusters revealed that a single cluster was primarily segmented into small gene groups among various genomes, which were further reorganized as novel clusters based on various functional genes. The individual phylogenies of gene and protein sequences supported that the clusters were assembled through the relocation of native orthologous genes that underwent insertion, deletion, and elongation events. Furthermore, the neighboring genes provided valuable evolutionary and functional cues regarding the conservation and maintenance of PHA-related genes in the genome. Overall, the aforementioned results strongly indicate the influence of horizontal gene transfer on the organization of PHA-related gene clusters. Therefore, our results reveal new insights into the organization, evolutionary history, and cluster conservation of the PHA-related gene inventories among Betaproteobacterial organisms.

Genome characteristics dictate poly-R-(3)-hydroxyalkanoate production in Cupriavidus necator H16.

Cupriavidus necator H16 is a well-recognized enterprise with efficient manufacturing machineries to produce diverse polymers belonging to polyhydroxyalkanoates (PHAs) family. The genome fingerprints, including PHA machinery proteins and fatty acid metabolism, had educated engineering strategies to enhance PHAs production. This outstanding progress has enlightened us to present an exhaustive examination of the ongoing research, addressing the great potential design of genome features towards PHA production and furthermore, we show how those acquired knowledge have been explored in other biotechnological applications. This updated-review concludes that the combination of an optimal strain selection, suitable metabolic engineering and a large-scale fermentation on oil substrates is critical to endow the ability of incorporating mcl-PHAs monomers in this organism.

A feeding strategy for incorporation of canola derived medium-chain-length monomers into the PHA produced by wild-type Cupriavidus necator.

The aim of this study was to increase the density of wild type Cupriavidus necator H16 biomass grown on fructose in order to produce sufficient copolymer of short-chain-length (scl) and medium-chain-length (mcl) polyhydroxyalkanoate (PHA) from canola oil for mechanical testing of the PHA. Initial batch cultivation on fructose was followed by exponential feeding of fructose at a predetermined µ to achieve 44.4 g biomass/l containing only 20 % w/w of polyhydroxybutyrate (PHB) with a Y(x/fructose) of 0.44 g/g. In a third stage, canola oil was added under N-limited conditions to produce 92 g/l of biomass with 48 % w/w scl-mcl PHA. Using known standards, the PHA composition was confirmed by GC-MS analysis as 99.81 % 3-hydroxybutyrate, 0.06 % 3-hydroxyvalerate, 0.09 % 3-hydroxyhexanoate and 0.04 % 3-hydroxyoctanoate. The melting temperature (179 °C), crystallinity (54 %), tensile stress (25.1 Mpa) and Young's modulus (698 Mpa) for a PHB standard decreased to 176 °C, 52 %, 19.1 and 443 Mpa respectively for C. necator PHA produced in the 3-stage process.

Plastisphere-hosted viruses: A review of interactions, behavior, and effects.

Microbial communities, including bacteria, diatoms, and fungi, colonize plastic surfaces, forming biofilms known as the "plastisphere." Recent research has revealed that plastispheres also host a wide range of viruses, sparking interest in microbial ecology and virology. This shared habitat allows viruses to replicate, interact, infect, and spread, potentially impacting the environment and human health. Consequently, viruses attached to microplastics are now recognized to have broad effects on cellular and immune responses. However, the ecology and implications of viruses hosted in plastisphere habitats remain poorly understood, highlighting their fundamental importance as a subject of study. This review explores various pathways for virus attachment to plastispheres, factors influencing these interactions, their impacts within plastisphere and host-associated environments, and associated issues. It also summarizes current research and identifies knowledge gaps. We anticipate that this paper will help improve our predictive understanding of plastisphere viruses in natural settings and emphasizes the need for more research in real-world environments to advance the field.

Microplastisphere antibiotic resistance genes: A bird's-eye view on the plastic-specific diversity and enrichment.

The microplastisphere is a dense consortium of metabolically active microorganisms that develops on the surface of microplastics. Since the discovery that it harbors antibiotic resistance genes (ARGs), there has been a quest to decipher the relationship between ARG occurrences and selective enrichment with plastic types, which is important to understand their fate in diverse environmental settings. Nonetheless, it remains a neglected topic, and this developing field of microplastics research could benefit from a comprehensive review to acquire a deeper understanding of the most recent advances and drive scientific progress. Accordingly, the goal of this review is to critically discuss and provide an in-depth assessment of the evidence of ARGs' global nature in microplastispheres, as well as explore factors that influence them directly and indirectly, highlighting important concerns and knowledge gaps throughout the article. By comprehensively covering them, we underscore the potential environmental implications associated with microplastisphere ARGs. From our analysis, it emerged that microplastisphere ARGs are likely to be impacted not only by differences in microplastic types and characteristics but also by how their environments are shaped by other agents such as physiochemical properties, socioeconomic factors, and contaminants coexistence, influencing ARG subtype, incidence, abundance, and selective enrichment. The intricate relationship of microplastisphere ARGs to environmental conditions and plastic types calls for multilevel investigations to clearly assess the environmental fate of microplastics. We anticipate that this review could assist researchers in strengthening their foundation and identifying efforts to advance knowledge in this research field.

Microplastic contamination in commercially packaged edible seaweeds and exposure of the ethnic minority and local population in Mexico.

Diet is an important pathway for microplastic exposure. This study examined distinct edible seaweed products sold at ethnic food stores in Mexico for microplastic contamination, as well as the exposure of the Asian ethnic minority and local population to microplastics. Microplastics were extracted from seaweed samples using a wet oxide digestion with hydrogen peroxide followed by zinc chloride density separation. They were subsequently detected, quantified, and the polymer type was determined via microscopic inspection and Fourier transform infrared spectroscopy. Microplastic contamination was detected in all samples, with an average abundance of 24.0 ± 9.4 items g-1. Fibrous-shaped (61 %) and non-colored (57 %) microplastics were prevalent. Microplastics with sizes smaller than 0.2 mm prevailed (60 %), and they have the potential to penetrate gut barriers and endanger human health. Polymers identified consisted of polyethylene-polypropylene, polyamide, cellophane, rayon, and polyethylene terephthalate. According to pollution load index values, seaweed samples were minimally contaminated with microplastics, with values ranging between 3.7 and 6.0. The estimated yearly intake of microplastic from seaweed consumption by the South Korean and Chinese populations in Mexico was 5.8 × 104 ± 2.3 × 104 and 5.7 × 104 ± 4.9 × 104, respectively. This study's findings highlight the importance of improved control measures for minimizing microplastics in foods for export.

Do microbial decomposers find micro- and nanoplastics to be harmful stressors in the aquatic environment? A systematic review of in vitro toxicological research.

Microbial decomposers (bacteria and fungi) are likely to interact with plastic particles introduced into natural systems, particularly micro- and nanoplastics (MNPs), exposing them to a variety of risks. In vitro testing has proven to be an accessible and viable method for gaining insights into how microbial decomposers behave individually and systemically toward MNPs. Recent advances have enhanced our understanding of MNP interactions with organisms, revealing the molecular foundations of adaptive responses as well as the biological impact and potential risks to MNPs. Despite widespread attention, this topic has not yet been reviewed. Here, we conducted a systematic review of the available research to critically assess and highlight the most recent advances in two major areas: (1) methods for in vitro evaluation of environmentally relevant microbial decomposers to MNPs; and (2) current understanding of the underlying toxicity mechanisms gained from in vitro assessments. We also addressed the key considerations throughout and proposed available opportunities in the field. Our analysis revealed that MNPs' toxicity has been studied in vitro either alone or in combination with other contaminants (e.g., antibiotics and metallic nanoparticles), with Escherichia coli and polystyrene particles receiving the most attention. Moreover, there were methodological differences in terms of MNP size, shape, polymer, surface characteristics, exposure period, and concentrations. A combination of methods, including growth-viability tests, biochemical assays, and omics profiling (metabolomics and transcriptomics), were employed to detect the effects of MNP exposure and explain its toxicity mechanism. The current literature suggests that the impacts of MNPs on microbial decomposers include alterations in the antioxidative system, gene expression levels and cell-membrane permeability and oxidative damage, all of which can be further influenced by MNPs interaction with other contaminants. This review will thus provide critical insights and up-to-date knowledge to assist novices and experts in promoting advancements and research.

Putting eggs on marine litter: Towards an understanding of a cause for concern.

Marine litter, including plastic litter, represent a serious environmental problem at a global scale. Plastics in marine litter have been documented on few occasions as serving as a unique substrate for fish oviposition in the oceans. The main goal of this viewpoint is to add to the previous discussion of fish oviposition and marine litter concerns by pointing out current research needs.

Microplastic diagnostics in humans: "The 3Ps" Progress, problems, and prospects.

The growing global concern about human exposure to microplastics necessitates research into their occurrence, fate, and effects. Recent advancements in analytical methods have fostered research and improved understanding of microplastics in a variety of human tissue and biological samples, including blood, liver, lung, placenta, kidney, spleen, sputum, and feces, etc. Given the rapid expansion of this research topic, it is imperative to assess and introduce them to a broader audience. This article for the first time conducts a systematic review of the literature on microplastics in human biological samples, their objectives, current efforts, and key findings. This review offers an in-depth analysis of the research approaches employed, spanning from sampling to detection to quantification of microplastics, as well as an overview of their occurrence and characteristics to understand the level of microplastic exposure in the human body. It also provides a detailed analysis of existing contamination control procedures and attempts to build consistent cross-contamination prevention measures. Finally, we provide the reader with the guidelines on current microplastic research strategies, highlighting future directions. Overall, this synthesis will assist researchers in developing a multifaceted understanding of contemporary microplastic investigations in human biological samples.

An assessment of higher-value recyclable wastes in Mexico City households using a novel waste collector citizen science approach.

The ability to accurately characterize and collect data on household waste generation and composition is essential for promoting recycling and developing city management plans. However, traditional data collection approaches in developing countries are hampered by jurisdictional and budgetary constraints. Here, we explore whether citizen science projects that collaborate with waste collectors can solve this problem and be a viable tool for addressing household waste generation across temporal and geographic boundaries. In this regard, this first study evaluated recyclable household waste generation by engaging waste collectors both door-to-door individuals and trucks as citizen scientists daily in an urbanized colony (5797 inhabitants and 1747 houses) in Mexico City between September and October 2022. To understand their distribution and consumption patterns on a regional basis, we stratified the colony's households into 2 distinct non-overlapping sub zones and one Wednesday market based on waste collectors' routine using a Geographical Information System. Results show that for seven weeks, household waste constitutes up to 12.19 t of recyclables, ranging from 99.5 to 480.8 kg/day, with 35 % cardboard, 23 % PET plastics, 21 % hard plastics, 17 % glass, and 4 % aluminum. The average amount of recyclable waste produced was 54 g/person/day, resulting in an annual recycling generation of 114 t. Statistical analysis revealed that recyclable waste generation varied by day and subzone. Furthermore, informal centers rather than municipal waste disposal facilities are in charge of the final disposition of the collected recyclables, suggesting that a substantial waste proportion may go unaccounted for in the local government's annual MSW report and calling for the implementation of formal recycling sectors. Overall, this study show how effective waste collector engagement in science can be and imply that the proposed citizen science approach is vital for future waste projects and the generation of transparent datasets in developing cities.

First evidence of microplastic contamination in ready-to-use packaged food ice cubes.

Concern over microplastics has grown tremendously, and they have been found in all environmental compartments; yet, much remains unknown regarding their impact on a variety of human-consuming food products. Here, we contribute to ongoing research by screening the 15 most popular commercial brands of packaged food ice cubes in Mexico City for microplastics. Microplastics were detected in 100% of the samples evaluated, with concentrations ranging from 19 ± 4 to 178 ± 78 L-1. There was a significant difference in the microplastic concentration across samples. The mean microplastic concentration was 79 ± 47 L-1, and the main types were polypropylene, polyethylene, polyvinyl alcohol, tygon polymer, sealing ring gardena 2824 large, polyamide 6, and cellophane. Moreover, microplastics that are fibrous (87%), non-colored (54%), and less than 300 µm in size (63%), were found to be more prevalent. The SEM-EDX analysis showed heterogeneous structural and morphological characteristics of microplastics, as well as traces of Si, S, Ti, Ca, Al, and Na. Furthermore, we estimate that ice cube consumption in Mexico City can result in the inadvertent ingestion of 4.9 × 102 ± 3.4 × 102-1 × 104 ± 7.2 × 103 microplastics annually. The findings of the study revealed that microplastics were identified in ice cubes and can be conveyed to humans, stressing the need of managing and eradicating such contamination from our food.

Consumption of commercially sold dried fish snack "Charales" contaminated with microplastics in Mexico.

Inadvertent human exposure to microplastics by the ingestion of microplastic-contaminated processed foods poses health risks and new preventative issues; nevertheless, investigations analyzing microplastic occurrences in commercially dried fish for direct human consumption are scarce. This study assessed the abundance and characteristics of microplastics in 25 commercially sold dried fish products (4 supermarkets, 3 street vendors, and 18 traditional agri-product farmers' markets) from two widely consumed and commercially important Chirostoma species (C. jordani and C. patzcuaro) in Mexico. Microplastics were detected in all the samples examined, with abundances ranging from 4.00 ± 0.94 to 55.33 ± 9.43 items g-1. C. jordani dried fish samples had higher mean microplastic abundance (15.17 ± 5.90 items g-1) than the C. patzcuaro dried fish samples (7.82 ± 2.90 items g-1); nevertheless, there was no statistically significant difference in microplastic concentrations between the samples. The most prevalent type of microplastic was fiber (67.55%), followed by fragment (29.18%), film (3.00%), and sphere (0.27%). Non-colored microplastics (67.35%) predominated, while microplastic sizes varied from 24 to 1670 µm, with sizes less than 500 µm (84%) being the most common. ATR-FTIR analysis revealed polyester, acrylonitrile butadiene styrene, polyvinyl alcohol, ethylene-propylene copolymer, nylon-6 (3), cellophane, and viscose in the dried fish samples. Overall, this study's findings are the first in Latin America to demonstrate microplastic contamination in dried fish for human consumption, underscoring the need for developing countermeasures to prevent plastic pollution in fish-caught regions and reduce the risks of human exposure to these micropollutants.

Common laboratory reagents: Are they a double-edged sword in microplastics research?

Understanding and communicating instances of microplastic contamination is critical for enabling plastic-free transitions. While microplastics research uses a variety of commercial chemicals and laboratory liquids, the impact of microplastics on these materials remains unknown. To fill this knowledge gap, the current study investigated microplastics abundance and their characteristics in laboratory waters (distilled, deionized, and Milli-Q), salts (NaCl and CaCl2), chemical solutions (H2O2, KOH and NaOH), and ethanol from various research laboratories and commercial brands. The mean abundance of microplastics in water, salt, chemical solutions, and ethanol samples was 30.21 ± 30.40 (L-1), 24.00 ± 19.00 (10 g-1), 187.00 ± 45.00 (L-1), and 27.63 ± 9.53 (L-1), respectively. Data comparisons revealed significant discrepancies between the samples in terms of microplastic abundance. Fibers (81 %) were the most common microplastics, followed by fragments (16 %) and films (3 %); 95 % of them were <500 µm, with the smallest and largest particle sizes recorded being 26 µm and 2.30 mm, respectively. Microplastic polymers discovered included polyethylene, polypropylene, polyester, nylon, acrylic, paint chips, cellophane, and viscose. These findings lay the groundwork for identifying common laboratory reagents as a potential contributor to microplastic contamination in samples, and we offer solutions that should be integrated into data processing to produce accurate results. Taken together, this study shows that commonly used reagents not only play a key role in the microplastic separation process but also contain microplastic contamination themselves, requiring the attention of researchers to promote quality control during microplastic analysis and commercial suppliers in formulating novel prevention strategies.

(Micro)plastics: A possible criterion for beach certification with a focus on the Blue Flag Award.

On the one hand, environmental certifications like the Blue Flag award (BFA) are well-known globally for its role in beach management and tourism attraction. Plastic pollution like microplastics, on the other hand, has become a global concern due to their increasing persistence and negative environmental repercussions. This paper examines and discusses the factors that would lead to (micro)plastics being included to the BFA as a criterion. Thereby, we attempt to maximize BFA's potential as a tool for better understanding (micro)plastics on beaches and implementing strategies to reduce them. The anticipated primary benefits are: 1) knowing the degree of litter disposal and microplastic contamination, 2) conducting close monitoring, 3) having an accessible database for numerous coastlines throughout the world, 4) evaluating management strategies and making improvements, 5) assisting in long-term research, 6) having a responsible entity in charge of issue decision-making, and 7) a larger public/scientific outreach.

A critical synthesis of current peer-reviewed literature on the environmental and human health impacts of COVID-19 PPE litter: New findings and next steps.

Since the emergence of Coronavirus disease (COVID-19), the threat of plastic waste pollution has grown exponentially, with a strong attention on the environmental and human health consequences of millions of personal protective equipment (PPE) (e.g., face masks, shields, gloves, and wipes) being used and discarded. In response, a massive research effort has been launched to understand, characterize, and estimate the exposure risks of PPE associated contaminants. While the number of studies examining the impacts of PPE is increasing, this review aimed to provide a quick update on the research conducted to date of this topic, as well as to identify priorities for future research. Specifically, we analyzed recent global peer-reviewed articles on PPE to synthesize methods, control measures, and documented evidence to (1) investigate the discarded PPE in a variety of environments; (2) determine the microplastics discharge in the aquatic environment; (3) examine the intentionally or unintentionally added chemicals in the production of PPE; and (4) assess potential human health hazards and exposure pathways. Despite progress, more research is needed in the future to fully understand the chemical emissions from PPE degradation mechanisms (mechanical, chemical, and biological), as well as the magnitude and density of PPE pollution in the environment.

Analyzing microplastics with Nile Red: Emerging trends, challenges, and prospects.

The development and applications of effective analytical techniques for identification and quantification of microplastics in diverse spheres are increasing in the scientific arena. Nile Red (NR) staining has progressed as a low-cost, simple-to-use approach for analyzing the environmental impact of a wide spectrum of microplastics (e.g., ≥ 3 µm - ≤ 5 mm; polyethylene, polypropylene, and polyvinyl chloride etc.). Given the recent surge of research into this methodology, it is critical to examine the findings and present future directions. Herein, we review accomplishments to date of the current protocols describing the sample preparation, staining and fluorescence conditions, contamination measures, and data analysis based on 56 field observations focusing on microplastic pollution and NR staining technique. Additionally, we discuss the challenges in current analyses towards standardization and recommendations related to it. Finally, we conclude that, despite methodological discrepancies, the NR method has emerged as a viable standalone substitute for visual identification; yet not all that fluoresce with NR are microplastics, which necessitates extensive sample preparation or additional spectroscopy techniques for chemical analysis to validate the results. This article informs the reader about how the NR technique is advancing microplastic research and identifies current needs for future advancements.

Surface water quality in the upstream of the highly contaminated Santiago River (Mexico) during the COVID-19 lockdown.

The Santiago River (Jalisco) is a major waterway in western Mexico and has received considerable attention due to its severe pollution. Understanding the impact of reduced human activity on water quality in the Santiago River during the COVID-19 lockdown (April-May 2020) is critical for river management and restoration. However, there has been no published study in this context, presenting a significant knowledge gap. Hence, this study focuses on determining if the nationwide COVID-19 lockdown influenced or improved surface water quality in a 262-km stretch of the Santiago River upstream. Data for 15 water quality parameters collected during the lockdown were compared to levels obtained in 2019 (pre-lockdown), 2021 (unlock), and the previous eleven years (2009-2019). The values of turbidity, BOD, COD, TSS, f. coli, t. coli, nitrate, sulfate, and Pb decreased by 4-36%, while pH, EC, total nitrogen, and As increased by 0.3-21% during the lockdown compared to the pre-lockdown period, indicating a reduction in organic load in the river due to the temporary closure of industrial and commercial activities. An eleven-year comparison estimated a 0-38% decline in pH, TSS, COD, total nitrogen, sulfates, nitrates, and Pb. The unlock-period comparison showed a significant rise of 3-37% in all parameters except As, highlighting the potential repercussions of restoring activity along the Santiago River. Estimated water quality indices demonstrated short-term improvements in river water quality during the lockdown when compared to other time periods investigated. According to factor analysis, the main pollution sources influencing river water quality were untreated household sewage, industrial wastewater, and agricultural effluents. Overall, our analysis showed that the COVID-19-imposed lockdown improved the water quality of the Santiago River, laying the groundwork for local officials to identify pollution sources and better support environmental policies and water quality improvement plans. Supplementary Information: The online version contains supplementary material available at 10.1007/s12665-022-10430-9.

Coverage of microplastic data underreporting and progress toward standardization.

The analysis of microplastics in various environmental matrices is becoming more prevalent in almost every region of the world. Microplastics are underreported depending on how they are extracted and analyzed, and their magnitude and impacts are unknown or unstudied. This paper aims to synthesize a concrete assessment of the important factors that underpin microplastics data underreporting. Our analysis revealed that there is considerable evidence to highlight data underreporting on microplastic abundance and characteristics, which stems from a combination of partial evaluation, economic constraints, recovery efficiency of microplastic extraction, filter pore size used for microplastic separation, and the detection limit of the quantification and characterization method. The majority of unreported data fell into the category of significantly smaller-sized microplastic particles (1-300 µm), which are known to be more harmful to the environment and human health. Recommendations toward the improvement of methodologies for improving microplastic data, as well as the critical areas that will drive standardization ahead, are addressed.