Honeybees as active samplers for microplastics

Microplastic contamination in the agri-food chain: The case of honeybees and beehive products

Microplastics, MPs, plastic fragments with a dimension lower than 5 mm, and microfibers, MFs, synthetic and natural/artificial fibrous fragments with a diameter lower than 50 μm, are ubiquitous pollutants identified in different environmental compartments. In this work the occurrence of MPs and MFs on honeybees, Apis mellifera, and beehive products was evaluated, using Fourier transform infrared microspectroscopy, confirming that MPs and MFs are widely present as air contaminants in all the apiary's areas (high and low urbanized areas) in Southern Italy. Results indicated that independently from the site, both honeybees and honey samples, are contaminated by MFs with non-natural color. The majority of MFs were of natural origin followed by artificial MFs and synthetic MFs. Moreover, the chemical composition of MFs isolated from honeybees reflect that used in synthetic fabrics, leading to the hypothesis that they are released from textile to air where are captured by bees. Results highlight that MFs represent a class of ubiquitous airborne anthropogenic pollutants. The identification of polytetrafluoroethylene, PTFE, MPs in honeybees confirm the recent findings that PTFE MPs are diffuse soil and air contaminants while the identification of polyethylene, PE, based MPs in honey samples, from low density urban sites, could be correlated to the large use of PE in agriculture. In the honey samples, also polycaprolactone, PCL, MPs were identified, mainly in high density urban sites, confirming that biodegradable materials could be further pollutants in the environments. The results indicate that honeybees are contaminated by MPs and MFs during their flights or picking up from the hive components, flowers, from other nest mates, from the clothes of the beekeeper, among others and some of them could be transferred to honey samples that could be also affected by soil contamination.

Phenotypic and genotypic antimicrobial resistance patterns in honey bee (Apis mellifera L.) bacterial symbionts

Antimicrobial resistance (AMR) is a major global public health problem. Nevertheless, the knowledge of the factors driving the spread of resistance among environmental microorganisms is limited, and few studies have been performed worldwide. Honey bees (Apis mellifera L.) have long been considered bioindicators of environmental pollution and more recently also of AMR. In this study, 53 bacterial strains isolated from the body surface of honey bees at three ontogenetic stages, collected from ten different geographic locations, were tested for their phenotypic and genotypic resistance to eight classes of the most widely used antimicrobials in human and veterinary medicine. Results showed that 83% of the strains were resistant to at least one antimicrobial and 62% were multidrug-resistant bacteria, with a prevalence of resistance to nalidixic acid, cefotaxime, and aztreonam. A high percentage of isolates harbouring at least one antimicrobial gene was also observed (85%). The gene encoding resistance to colistin mcr-1 was the most abundant, followed by those for tetracycline tetM and tetC. Geographical features influenced the distribution of these traits more than bacterial species or bee stage, supporting the use of honey bee colonies and their associated bacteria as indicators to monitor environmental resistance. This approach can improve the scientific understanding of this global threat by increasing data collection capacity.

Using honey bee colonies to monitor phenotypic and genotypic resistance to colistin

Colistin is a polymyxin antimicrobic mainly used to treat infection caused by multi-drug resistant Gram-negative bacteria. Mechanisms of colistin resistance are linked to the mobile colistin resistance (mcr) genes, which are transferable within mobile plasmids. Currently, there is limited research on the environmental dissemination of these genes. The behavioural and morphological characteristics of Apis mellifera L. make honey bees effective environmental bioindicators for assessing the prevalence of antimicrobial-resistant bacteria. This study aims to evaluate the colistin phenotypic and genotypic resistance in environmental Gram-negative bacteria isolated from foraging honey bees, across a network of 33 colonies distributed across the Emilia-Romagna region in Italy. Phenotypic resistances were determined through a microdilution assay using the minimum inhibitory concentration (MIC) with dilutions ranging from 0.5 μg/ml to 256 μg/ml. Strains with MIC values gather than 2 μg/ml were classified as resistant. Also, the identification of the nine mcr genes was carried out using two separate multiplex PCR assays. The study found that 68.5% of isolates were resistant and the genus with the higher resistance rates observed in Enterobacter spp. (84.5%). At least one mcr gene was found in 137 strains (53.3%). The most detected gene was mcr5 (35.3%), which was the most frequently detected gene in the seven provinces, while the least observed was mcr4 (4.8%), detected only in two provinces. These results suggested the feasibility of detecting specific colistin resistance genes in environmentally spread bacteria and understanding their distribution at the environmental level, despite their restricted clinical use. In a One-Health approach, this capability enables valuable environmental monitoring, considering the significant role of colistin in the context of public health.

More than just sweet: current insights into microplastics in honey products and a case study of Melipona quadrifasciata honey

Honey, traditionally known as a pure and natural substance, has become an unexpected reservoir for microplastic contamination. This study consisted of an experimental investigation to assess the occurrence of microplastics in honey produced by Melipona quadrifasciata, a native bee species in Brazil. Our investigation covers eight areas (one sample per area), including built and vegetated areas located in São Paulo city, Brazil, to understand the distribution of microplastics in these environments. Honey samples (10 mL) were collected using a syringe and sent to the laboratory for further analysis. Microplastics extracted from honey samples were characterized under a stereomicroscope to determine their size, color, and morphology. Also, the polymer type was determined by FTIR analysis. All honey samples (100%) showed microplastics. The predominant particles displayed a fiber shape with a size below 299 μm and a transparent color and were primarily composed of polypropylene. Their concentrations ranged from 0.1 to 2.6 particles per mL of honey, raising concerns about their potential impact on bee populations and human consumers. This study underscores the need for further research on the sources and implications of microplastic contamination in Melipona quadrifasciata honey, shedding light on the broader issue of environmental plastic pollution and its impact on pollinators.

Ants avoid food contaminated with micro- and nanoplastics

Micro- and nanoplastics (MNP) have recently received particular attention in freshwater and marine ecosystems, but less is known about their impact on terrestrial species. Ants can be used as biological indicators for many types of pollutants and are therefore a good candidate to explore the effects of MNP pollution. In the present study, we investigated the ability of workers from seven colonies of the acrobat ant Crematogaster scutellaris to detect MNP in their food. After two days of starvation, groups of ten ants were tested for their preference toward control and polyethylene-treated solutions. Every 5 min over a total 20 min period, the number of workers feeding on either solution was counted. The results showed that C. scutellaris workers could detect and avoid contaminated food, feeding more often on the uncontaminated solution in the first 10 min. However, after 10 min the food preference was no longer significant between the groups, likely owing to feeding satiation. We then assessed whether this feeding behaviour is sufficient to cause the accumulation of MNP in the ant. We thereby provided a solution containing fluorescent MNP (fMNP) at the same concentration as in the previous experiments. Observation of the ants' mouthparts using fluorescent light microscopy showed that after 10 min dense aggregations of fMNP were visible. Further investigations are needed to understand the mechanisms of detection of MNP by ants, and the accumulation dynamics in ants' bodies. Moreover, the effects of MNP on the integrity and fitness of ant colonies, as well as the potential transfer across terrestrial trophic chains should be explored.

First occurrence and risk assessment of microplastics in enteral nutrition formulas

Occurrence and characteristics of microplastics were evaluated in enteral nutrition formulas, for the first time. A total of 30 samples belonging to 9 brands were analysed. Physical and chemical characteristics of microplastics were identified by stereomicroscopy and micro-raman spectroscopy, respectively. The mean number of microplastics was 45 ± 63 MP/L. Two different shapes of microplastics were detected with fibres (62%) being the most common microplastics followed by fragments (38%). The most common color of microplastics was black (37%) followed by blue (26%), orange (15%), green (7%), red (7%), grey (4%) and multicolor (4%). The length of microplastics ranged from 10 to 2086 μm with an average of 548 ± 526 μm. Estimated mean daily microplastic intake for four different scenarios varied between 24 to 61 and 30 to 76 MPs/day for women and men, respectively. The mean polymer hazard index and microplastic load index levels were calculated as 380 and 1.30, respectively. The results of this study showed that microplastics are prevalent in enteral nutrition products. The presence of polymers with high hazard risk scores in enteral nutrition formulas may pose a risk to the health of patients with special nutritional needs.

Tracking fine particles in urban and rural environments using honey bees as biosamplers in Mexico

This work explores the efficiency of honey bees (Apis mellifera) as biosamplers of metal pollution. To understand this, we selected two cities with different urbanization (a medium-sized city and a megacity), and we collected urban dust and honey bees captured during flight. We sampled two villages and a university campus as control areas. The metal content in dust was analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Atomic Force Microscopy (AFM) and Scanning electron microscopy (SEM) were used to investigate the shape and size distribution of the particles, and to characterize the semiquantitative chemical composition of particles adhered to honey bee's wings. Principal Component Analysis (PCA) shows a distinctive urban dust geochemical signature for each city, with component 1 defining V-Cr-Ni-Tl-Pt-Pb-Sb as characteristic of Mexico City and Ce-As-Zr for dust from Hermosillo. Particle count using SEM indicates that 69% and 63.4% of the resuspended dust from Hermosillo and Mexico City, respectively, corresponds to PM2.5. Instead, the particle count measured on the honey bee wings from Hermosillo and Mexico City is mainly PM2.5, 91.4% and 88.9%, respectively. The wings from honey bees collected in the villages and the university campus show much lower particle amounts. AFM-histograms confirmed that the particles identified in Mexico City have even smaller sizes (between 60 and 480 nm) than those in Hermosillo (between 400 and 1400 nm). Particles enriched in As, Zr, and Ce mixed with geogenic elements such as Si, Ca, Mg, K, and Na dominate honey bee' wings collected in Hermosillo. In contrast, those particles collected from Mexico City contain V, Cr, Ni, Tl, Pt, Pb, and Sb. Such results agree with the urban dust data. This work shows that honey bees are suitable biosamplers for the characterization of fine dust fractions by microscopy techniques and reflect the urban pollution of the sites.

The potential use of birds as bioindicators of suspended atmospheric microplastics and artificial fibers

Microplastics (MPs) and artificial fibers (AFs) have been detected suspended tens of meters above ground level in the atmosphere, yet empirical data on them remain scarce. This study aimed to investigate the presence of MPs and AFs in the digestive and respiratory systems of two abundant bird species, the Common House Martin (Delichon urbicum) and the Common Swift (Apus apus), within the Community of Madrid, Spain. Given that these birds spend the majority of their lives airborne, engaging in activities such as mating and sleeping during flight, the research sought to assess the potential of using these bird species as bioindicators for suspended atmospheric MPs and AFs. Samples were obtained from necropsies of birds (N = 24) collected primarily between spring and summer from 2021 to 2023. Only individuals that died within the initial 24-hour period and had not been fed were selected for examination to avoid contamination. MPs and AFS were identified by micro-FTIR, characterized and quantified. Results revealed that 75 % of the sampled birds exhibited at least one MPs in their respiratory and/or digestive system. All identified MPs were fibers, with polyester (PES) being the most predominant (48 %), followed by acrylic fibers (ACR; 28 %), and polyethylene (PE; 18 %). The average concentrations in the respiratory system were 1.12 ± 0.45 MPs/specimen and 2.78 ± 1.04 AFs/specimen for Common Swift and 0.75 ± 0.30 MPs/specimen and 0.75 ± 0.36 AFs/specimen for House Martin. In the digestive system, these were 1.92 ± 0.72 MPs/specimen and 3.42 ± 0.69 AFs/specimen for Common Swift, and 1.34 ± 0.50 MPs/specimen and 1.39 ± 0.47 AFs/specimen for House Martin. Birds collected areas with high population density located in the direction of the prevailing winds showed a concentration of MPs significantly higher in the digestive system. Taken together, these findings confirmed the potential use of these birds as bioindicators for monitoring of suspended atmospheric MPs and AFs.

Dancing with danger-how honeybees are getting affected in the web of microplastics-a review

Anthropogenic activities have negatively impacted the ecosystem dramatically over the last few decades. The environment is becoming more contaminated with heavy metals, pesticides, and microplastics (MPs) as a result of the swift rise in industrialization and urbanisation. These contaminants are present everywhere in the ecosystem, affecting every living creature, from aquatic to terrestrial to aerial. Recently, the widespread of microplastics in the environment has raised serious concerns about the contamination of honey bees by these tiny particles of plastic. Honeybees are the major pollinators which contributes in the pollination of about 70% food that we consume. This review summarizes current research findings on the presence, uptake, and possible effects of microplastics on honey bees. Findings revealed the presence of microplastics in various honey bee matrices, such as honey, pollen, beeswax, and bee bodies, highlighting the potential routes of exposure for these vital pollinators. Additionally, evidence suggests that microplastics can accumulate in honey bee tissues (brain, midgut, Malpighian tubules, trachea, and haemolymph) potentially leading to adverse effects on honey bee health, behaviour, and colony dynamics. Additionally, MPs has a synergistic impact on immune system as well. Change in cuticle profile, reduction in body weight, and changes in eating frequency can regulate overall success rate of their survival. However, significant knowledge gaps remain regarding the long-term consequences for honey bee populations and ecosystem health, which cannot unveil the ultimate degree of future threats. Future research efforts should focus on investigating the interactions between microplastics and other stressors, such as pesticides and pathogens, and assessing the broader ecological implications of honey bee contamination with microplastics. Addressing these knowledge gaps is essential for developing effective mitigation strategies to minimize the impact of microplastics on honey bee populations and safeguarding their vital role in ecosystem functioning and food security.

Exposure Pathways and Toxicity of Microplastics in Terrestrial Insects

The detrimental effects of plastics on aquatic organisms, including those of macroplastics, microplastics, and nanoplastics, have been well established. However, knowledge on the interaction between plastics and terrestrial insects is limited. To develop effective strategies for mitigating the impact of plastic pollution on terrestrial ecosystems, it is necessary to understand the toxicity effects and influencing factors of plastic ingestion by insects. An overview of current knowledge regarding plastic ingestion by terrestrial insects is provided in this Review, and the factors influencing this interaction are identified. The pathways through which insects interact with plastics, which can lead to plastic accumulation and microplastic transfer to higher trophic levels, are also discussed using an overview and a conceptual model. The diverse impacts of plastic exposure on insects are discussed, and the challenges in existing studies, such as a limited focus on certain plastic types, are identified. Further research on standardized methods for sampling and analysis is crucial for reliable research, and long-term monitoring is essential to assess plastic trends and ecological impacts in terrestrial ecosystems. The mechanisms underlying these effects need to be uncovered, and their potential long-term consequences for insect populations and ecosystems require evaluation.

Exploring the risk of microplastics to pollinators: focusing on honey bees

The rapid increase in global plastic production and usage has led to global environmental contamination, with microplastics (MPs) emerging as a significant concern. Pollinators provide a crucial ecological service, while bee populations have been declining in recent years, and MPs have been recognized as a new risk factor contributing to their losses. Despite the pervasive distribution and persistence of MPs, understanding their risks to honey bees remains a critical knowledge gap. This review summarizes recent studies that investigate the toxicity of MPs on honey bee health from different perspectives. The findings revealed diverse and material-/size-/dosage-dependent outcomes, emphasizing the need for comprehensive assessments in the follow-up studies. MPs have been detected in honey and in bees' organs (e.g., gut and brain), posing potential threats to bee fitness, including altered behavior, cognitive abilities, compromised immunity, and dysfunction of the gut microbiota. It should be noticed that despite several laboratory studies suggesting the aforementioned adverse effects of MPs, field/semi-field experiments are still warranted. The synergistic toxicity of MPs with other environmental contaminants (pesticides, antibiotics, fungicides, heavy metals, etc.) still requires further investigation. Our review highlights the critical need to understand the relationships between MPs, pollinators, and the ecosystem to mitigate potential risks and ensure the sustainability of vital services provided by honey bees.

Unravelling the microplastic menace: Different polymers additively increase bee vulnerability

Microplastics (MPs) are growing and ubiquitous environmental pollutants and represent one of the greatest contemporary challenges caused by human activities. Current research has predominantly examined the singular toxicological effects of individual polymers, neglecting the prevailing reality of organisms confronted with complex contaminant mixtures and potential synergistic effects. To fill this research gap, we investigated the lethal and sublethal effects of two common MPs, polystyrene (PS - 4.8-5.8 μm) and poly(methyl methacrylate) (PMMA - 1-40 μm), and their combination (MIX), on the pollinating insect Apis mellifera. For each treatment, we evaluated the oral toxicity of two ecologically relevant and one higher concentration (0.5, 5 and 50 mg/L) and analysed their effects on the immune system and worker survival. As immune activation can alter the cuticular hydrocarbon profile of honey bees, we used gas chromatography-mass spectrometry (GC-MS) to investigate whether MPs lead to changes in the chemical profile of foragers and behavioural assay to test whether such changes affect behavioural patterns of social recognition, undermining overall colony integrity. The results indicate an additive negative effect of PS and PMMA on bee survival and immune response, even at ecologically relevant concentrations. Furthermore, alterations in cuticle profiles were observed with both MPs at the highest and intermediate concentrations, with PMMA being mainly responsible. Both MPs exposure resulted in a reduction in the abundance of several cuticular compounds. Hive entry guards did not show increased inspection or aggressive behaviour towards exposed foragers, allowing them to enter the colony without being treated differently from uncontaminated foragers. These findings raise concerns not only for the health of individual bees, but also for the entire colony, which could be at risk if contaminated nestmates enter the colony undetected, allowing MPs to spread throughout the hive.

Evaluation of microplastic pollution using bee colonies: An exploration of various sampling methodologies

Recent research has highlighted the potential of honeybees and bee products as biological samplers for monitoring xenobiotic pollutants. However, the effectiveness of these biological samplers in tracking microplastics (MPs) has not yet been explored. This study evaluates several methods of sampling MPs, using honeybees, pollen, and a novel in-hive passive sampler named the APITrap. The collected samples were characterized using a stereomicroscopy to count and categorise MPs by morphology, colour, and type. To chemical identification, a micro-Fourier transform-infrared (FTIR) spectroscopy was employed to determine the polymer types. The study was conducted across four consecutive surveillance programmes, in five different apiaries in Denmark. Our findings indicated that APITrap demonstrated better reproducibility, with a lower variation in results of 39%, compared to 111% for honeybee samples and 97% for pollen samples. Furthermore, the use of APITrap has no negative impact on bees and can be easily applied in successive samplings. The average number of MPs detected in the four monitoring studies ranged from 39 to 67 in the APITrap, 6 to 9 in honeybee samples, and 6 to 11 in pollen samples. Fibres were the most frequently found, accounting for an average of 91% of the total MPs detected in the APITrap, and similar values for fragments (5%) and films (4%). The MPs were predominantly coloured black, blue, green and red. Spectroscopy analysis confirmed the presence of up to five different synthetic polymers. Polyethylene terephthalate (PET) was the most common in case of fibres and similarly to polypropylene (PP), polyethylene (PE), polyacrylonitrile (PAN) and polyamide (PA) in non fibrous MPs. This study, based on citizen science and supported by beekeepers, highlights the potential of MPs to accumulate in beehives. It also shows that the APITrap provides a highly reliable and comprehensive approach for sampling in large-scale monitoring studies.

Predictive statistical models for monitoring antimicrobial resistance spread in the environment using Apis mellifera (L. 1758) colonies

The rise of antimicrobial resistance (AMR) is one of the most relevant problems for human and animal health. According to One Health Approach, it is important to regulate the use of antimicrobials and monitor the spread of AMR in the environment as well. Apis mellifera (L. 1758) colonies were used as bioindicators thanks to their physical and behavioural characteristics. During their foraging flights, bees can intercept small particles, including atmospheric particulate matter, etc., and also microorganisms. To date, the antimicrobial surveillance network is limited to the sanitary level but lacks into environmental context. This study aimed to evaluate the use of A. mellifera colonies distributed throughout the Emilia-Romagna region (Italy) as indicators of environmental antimicrobial-resistant bacteria. This was performed by creating a statistical predictive model that establishes correlations between environmental characteristics and the likelihood of isolating specific bacterial genera and antimicrobial-resistant strains. A total of 608 strains were isolated and tested for susceptibility to 19 different antimicrobials. Aztreonam-resistant strains were significantly related to environments with sanitary structures, agricultural areas and wetlands, while urban areas present a higher probability of trimethoprim/sulfamethoxazole-resistant strains isolation. Concerning genera, environments with sanitary structures and wetlands are significantly related to the genera Proteus spp., while the Escherichia spp. strains can be probably isolated in industrial environments. The obtained models showed maximum values of Models Accuracy and robustness (R2) of 55 % and 24 %, respectively. The results indicate the efficacy of utilizing A. mellifera colonies as valuable bioindicators for estimating the prevalence of AMR in environmentally disseminated bacteria. This survey can be considered a good basis for the development of further studies focused on monitoring both sanitary and animal pathology, creating a specific network in the environments of interest.

Biotic and abiotic stresses on honeybee health

Honeybees are the most critical pollinators providing key ecosystem services that underpin crop production and sustainable agriculture. Amidst a backdrop of rapid global change, this eusocial insect encounters a succession of stressors during nesting, foraging, and pollination. Ectoparasitic mites, together with vectored viruses, have been recognized as central biotic threats to honeybee health, while the spread of invasive giant hornets and small hive beetles also increasingly threatens colonies worldwide. Cocktails of agrochemicals, including acaricides used for mite treatment, and other pollutants of the environment have been widely documented to affect bee health in various ways. Additionally, expanding urbanization, climate change, and agricultural intensification often result in the destruction or fragmentation of flower-rich bee habitats. The anthropogenic pressures exerted by beekeeping management practices affect the natural selection and evolution of honeybees, and colony translocations facilitate alien species invasion and disease transmission. In this review, the multiple biotic and abiotic threats and their interactions that potentially undermine bee colony health are discussed, while taking into consideration the sensitivity, large foraging area, dense network among related nestmates, and social behaviors of honeybees.

Mind over Microplastics: Exploring Microplastic-Induced Gut Disruption and Gut-Brain-Axis Consequences

As environmental plastic waste degrades, it creates an abundance of diverse microplastic particles. Consequently, microplastics contaminate drinking water and many staple food products, meaning the oral ingestion of microplastics is an important exposure route for the human population. Microplastics have long been considered inert, however their ability to promote microbial dysbiosis as well as gut inflammation and dysfunction suggests they are more noxious than first thought. More alarmingly, there is evidence for microplastics permeating from the gut throughout the body, with adverse effects on the immune and nervous systems. Coupled with the now-accepted role of the gut-brain axis in neurodegeneration, these findings support the hypothesis that this ubiquitous environmental pollutant is contributing to the rising incidence of neurodegenerative diseases, like Alzheimer's disease and Parkinson's disease. This comprehensive narrative review explores the consequences of oral microplastic exposure on the gut-brain-axis by considering current evidence for gastrointestinal uptake and disruption, immune activation, translocation throughout the body, and neurological effects. As microplastics are now a permanent feature of the global environment, understanding their effects on the gut, brain, and whole body will facilitate critical further research and inform policy changes aimed at reducing any adverse consequences.

Evaluating the retention of airborne microplastics on plant leaf: Influence of leaf morphology

Airborne microplastics (AMPs) have been identified in both indoor and outdoor environments and account for a large portion of an individual's daily exposure to microplastics. Thus, it is crucial to find effective methods to capture and control the levels of AMPs and ultimately reduce human exposure. While terrestrial plants have been recognized for their effectiveness in capturing airborne particles, little is known about their ability to capture AMPs. This study investigated the ability of 8 natural plant species and 2 artificial plants to capture AMPs, as well as the influence of leaf morphology on this retention. Plant leaves were exposed to AMPs for two weeks, and deposited AMPs were characterized using a Micro-Fourier Transform Infrared (μ-FTIR)spectroscopy. Selected cleaned leaves were further digested, and the presence of subsurface AMPs was confirmed using μ-Raman spectroscopy. Results revealed that AMPs were retained on the leaves of all selected plant species at concentrations ranging from 0.02 to 0.87 n/cm2. The highest average concentration was observed on an artificial plant with fenestrated leaves, followed by natural plant species with trichomes and leaflets. The lowest concentration was observed on a natural plant with smooth leaves. The majority (90%) of retained AMPs were fibres, and the remaining were fragments. Polyethylene terephthalate (PET) was the prominent polymer type. Additionally, AMP fragments were observed in the leaf subsurface in one selected species, likely retained within the leaf cuticles. The results suggest that plant leaves can indiscriminately retain AMPs on their surfaces and act as temporary sinks for AMPs. Additionally, indoor plants may provide a useful functional role in reducing indoor AMP concentrations, although longer-term studies are needed to ascertain their retention capacity more accurately over time and to evaluate the capability of indoor plants to act as a suitable, cost-effective candidate for reducing AMPs.

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.

Enhancing knowledge of chemical exposures and fate in honey bee hives: Insights from colony structure and interactions

Honey bees are unintentionally exposed to a wide range of chemicals through various routes in their natural environment, yet research on the cumulative effects of multi-chemical and sublethal exposures on important caste members, including the queen bee and brood, is still in its infancy. The hive's social structure and food-sharing (trophallaxis) practices are important aspects to consider when identifying primary and secondary exposure pathways for residential hive members and possible chemical reservoirs within the colony. Secondary exposures may also occur through chemical transfer (maternal offloading) to the brood and by contact through possible chemical diffusion from wax cells to all hive members. The lack of research on peer-to-peer exposures to contaminants and their metabolites may be in part due to the limitations in sensitive analytical techniques for monitoring chemical fate and dispersion. Combined application of automated honey bee monitoring and modern chemical trace analysis techniques could offer rapid progress in quantifying chemical transfer and accumulation within the hive environment and developing effective mitigation strategies for toxic chemical co-exposures. To enhance the understanding of chemical fate and toxicity within the entire colony, it is crucial to consider both the intricate interactions among hive members and the potential synergistic effects arising from combinations of chemical and their metabolites.

Microplastics reach the brain and interfere with honey bee cognition

Scientific research on the impact of microplastics (MPs) in terrestrial systems is still emerging, but it has confirmed adverse health effects in organisms exposed to plastics. Although recent studies have shown the toxicological effects of individual MPs polymers on honey bees, the effects of different polymer combinations on cognitive and behavioural performance remain unknown. To fill this knowledge gap, we investigated the effects of oral exposure to spherical MPs on cognitive performance and brain accumulation in the honey bee Apis mellifera. We evaluated the acute toxicity, after a two-day exposure, of polystyrene (PS - 4.8-5.8 μm) and plexiglass (Poly(methyl methacrylate), or PMMA - 1-40 μm) MPs, and a combination of the two (MIX), at two environmentally relevant and one higher concentration (0.5, 5 and 50 mg L-1) and analysed their effects on sucrose responsiveness and appetitive olfactory learning and memory. We also used fluorescent thermoset amino formaldehyde MPs (1-5 μm) to explore whether microspheres of this diameter could penetrate the insect blood-brain barrier (BBB), using Two-Photon Fluorescence Microscopy (TPFM) in combination with an optimized version of the DISCO clearing technique. The results showed that PS reduced sucrose responsiveness, while PMMA had no significant effect; however, the combination had a marked negative effect on sucrose responsiveness. PMMA, PS, and MIX impaired bee learning and memory in bees, with PS showing the most severe effects. 3D brain imaging analysis using TFPM showed that 1-5 μm MPs penetrated and accumulated in the brain after only three days of oral exposure. These results raise concerns about the potential mechanical, cellular, and biochemical damage that MPs may cause to the central nervous system.

Interactions between microplastics and insects in terrestrial ecosystems-A systematic review and meta-analysis

The presence of microplastics (MPs) in terrestrial ecosystems has been confirmed worldwide. Due to their widespread distribution and diversity in habitats, insects will readily interact with MPs via various pathways. Although the topic of MP-insect interactions is still in the early stages of research, it is becoming increasingly important. We used a META approach with phylogenetic control and subgroup examination to summarize the evidence from both field and laboratory experiments in quantitative form. The field evidence suggests that insects can take and transfer MPs along food chains via ingestion and adherence. Also, they are active in the bio-fragmentation of MPs and the generation of secondary pollutants. The exposure to MPs impaired key biological traits of insects, mainly their behavior and health, such as reducing climbing ability and increasing oxidative stress. In terms of exposure conditions, the small-sized MPs can induce more severe effects on the insects, while the insect response to MPs was not significantly reliant on exposure times or MP concentrations based on the current evidence available. We propose that insects not only play roles in the redistribution of MPs spatially and in food chains via bio-fragmentation but are also threatened by MPs. Our research deepens our understanding of the environmental risks posed by MPs in insect ecosystems.

Environmental assessment of PAHs through honey bee colonies - A matrix selection study

The steady conditions of temperature, humidity and air flux within beehives make them a valuable location for conducting environmental monitoring of pollutants such as PAHs. In this context, the selection of an appropriate apicultural matrix plays a key role in these monitoring studies, as it maximizes the information that will be obtained in the analyses while minimizing the inaccurate results. In the present study, three apicultural matrices (honey bees, pollen and propolis) and two passive samplers (APIStrips and silicone wristbands) are compared in terms of the number and total load of PAHs detected in them. Samplings took place in a total of 11 apiaries scattered in Austria, Denmark, and Greece, with analyses performed by GC-MS/MS. Up to 14 different PAHs were identified in silicone wristbands and pollen, whereas the remaining matrices contained a maximum of five contaminants. Naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, and pyrene were found to be the most prevalent substances in the environment. Recovery studies were also performed; these suggested that the chemical structure of APIStrips is likely to produce very strong interactions with PAHs, thus hindering the adequate desorption of these substances from their surface. Overall, silicone wristbands placed inside the beehives proved the most suitable matrix for PAH monitoring through honey bee colonies.

Metabolomes of bumble bees reared in common garden conditions suggest constitutive differences in energy and toxin metabolism across populations

Cold tolerance of ectotherms can vary strikingly among species and populations. Variation in cold tolerance can reflect differences in genomes and transcriptomes that confer cellular-level protection from cold; additionally, shifts in protein function and abundance can be altered by other cellular constituents as cold-exposed insects often have shifts in their metabolomes. Even without a cold challenge, insects from different populations may vary in cellular composition that could alter cold tolerance, but investigations of constitutive differences in metabolomes across wild populations remain rare. To address this gap, we reared Bombus vosnesenskii queens collected from Oregon and California (USA) that differ in cold tolerance (CTmin = -6 °C and 0 °C, respectively) in common garden conditions, and measured offspring metabolomes using untargeted LC-MS/MS. Oregon bees had higher levels of metabolites associated with carbohydrate (sorbitol, lactitol, maltitol, and sorbitol-6-phosphate) and amino acid (hydroxyproline, ornithine, and histamine) metabolism. Exogenous metabolites, likely derived from the diet, also varied between Oregon and California bees, suggesting population-level differences in toxin metabolism. Overall, our results reveal constitutive differences in metabolomes for bumble bees reared in common garden conditions from queens collected in different locations despite no previous cold exposure.

Spatial distribution of atmospheric microplastics in bulk-deposition of urban and rural environments - A one-year follow-up study in northern Germany

Atmospheric microplastic deposition rates play a crucial role for calculating the input of microplastics in the environment and to further understand pollution patterns. In this study, the spatial and temporal distribution of atmospheric microplastic particles in urban and rural areas of Northern Germany was investigated. Therefore, eleven structurally diverse locations in Hamburg and Mecklenburg-Western Pomerania were equipped with bulk-deposition samplers in triplicates and sampled monthly between August 2019 and July 2020. The resulting 306 samples were treated with hydrogen peroxide (30 %) and sodium hypochlorite (6-14 %) to digest biological organic matter. The filters were subsequently stained with the lipophilic dye Nile Red and underwent visual microplastic identification via fluorescence microscopy. Fragments and fibers were quantified down to a cut-off size of 10 μm. The polymer composition of microplastic particles was investigated along a subset of particles via μ-Raman spectroscopy. The microplastic deposition rate for Northern Germany (89 ± 61 MP/m2/day) is in the same order of magnitude as those reported by previous studies. Significant differences in microplastic deposition rates were found between urban and rural sampling sites. Population density was identified as an important factor for greater amounts of microplastics and higher shares of fibers in urban samples. Special attention was given to the canopy cover at two forested sampling sites and an influence of the comb-out effect on atmospheric microplastic deposition was detected.

Management practice for small hive beetle as a source of microplastic contamination in honey and honeybee colonies

Microplastics (MP) have emerged as a widespread environmental contaminant affecting bee health. In this study we report on the impact of one of the cultural practices used to control the small hive beetle (SBH, Aethina tumida). Management of the beetle often includes the use of in-hive traps of different kinds, such as non-woven microfiber wipes. When placed inside the hive, bees chew on these wipes, which then become fuzzy and fray to the point where beetles become entangled in their fibers. The current study aimed to examine the composition of these microfiber sheets and to evaluate whether their use resulted in unintended MP contamination of bees and honey. We treated hives with one blue microfiber sheet placed on top of the frames for at least three months. After that time, we collected adult bees and honey samples from treated hives, control hives in the same apiary (control near), and control hives in an apiary 7.5 km away (control far). Honey from treated hives had a significantly greater number of blue MF than honey from the control hives (mean ± SD, treatment 11.83 ± 3.76, control near 2.25 ± 0.92 and control far 0.25 ± 0.5 MF/20 gr honey). Also, hives treated with the microfiber sheets had a significantly greater number of blue microfibers in the gut and cuticle of bees, than the control hives located in a different apiary. However, the control and treated bees located in the same apiary had a similar number of blue microfibers (mean ± SD, treatment 4.7 ± 2.28, control near 3 ± 1.63 and control far 0.5 ± 0.58 MF in 20 bees). Thus, the current study raises concerns of the use of microfibers sheets to trap the SBH as it results in the incorporation of microfibers into the ecosystem and the food chain.

The use of honey bee (Apis mellifera L.) as biological monitors for pathogenic bacteria and antimicrobial resistance: A systematic review

The phenomenon of antimicrobial resistance (AMR) is an increasingly real and relevant health problem. It is essential to verify the spread of this phenomenon in the environment. The European honey bee, Apis mellifera L., is a globally managed pollinator continuously used for biomonitoring thanks to its morphological and behavioural characteristics. During their foraging activities, a large number of honey bees move in the area surrounding the hive within a 1.5 km of radius. Besides, their body covered with hair and bristles are able to intercept pollen and minute particles, such as atmospheric particles, contaminants and microorganisms. For these reasons, A. mellifera L. is widely used as an environmental sentinel, especially for detecting pollutants, pesticides, microorganisms, and AMR. This systematic review aimed to collect and summarize the role of honey bee colonies as a biological monitor of AMR pathogenic bacteria and the environmental spread of antimicrobial resistance genes (ARGs). From honey bees were isolated a wide range of pathogenic and environmental bacteria strains, harbouring AMR and ARGs. However, AMR and ARGs were detected not only in environmental bacteria but also in symbiotic bacteria colonizing the bee gut. This systematic review highlights the employment of potential use of honey bees as AMR sentinel helpful for ecosystem health to implement possible control measures for humans, animals and plants, in the context of the "One-Health" approach.

Patterns and variability in the microplastic contamination along the southwest coast of India with emphasis on submarine groundwater discharge sites

Beach sediments of the southwest coast of India were analysed to estimate the microplastic contamination with emphasis on the submarine groundwater discharge (SGD) zones. Both SGD and non-SGD sites were assessed for abundance, morphotype and polymer type of microplastics. Microplastic load was 230.429 ± 62.87 particles per 100 g. Fibre, mainly blue, was the abundant morphotype, followed by fragment, foam and film. The polymer types were POLYETHYLENE (PE) (30.77 %), POLYPROPYLENE (PP) (26.92 %), POLYAMIDE (PA) (19.23 %), POLYSTYRENE (PS) (11.54 %), ETHYLENE VINYL ACETATE (EVA) (7.692 %) and POLYVINYL CHLORIDE (PVC) (3.846 %). The SGD zones exhibited higher microplastic contamination with statistically significant variations from non SGD sites. The study accounts the levels of microplastic contamination along the southwest coast of India, a major fishery zone. The higher abundance of microplastic in the SGD zones indicates the significance of subterranean groundwater through flow as a pathway of anthropogenic contaminants towards marine ecosystems.

There's something in the air: A review of sources, prevalence and behaviour of microplastics in the atmosphere

Literature regarding microplastics in the atmosphere has advanced in recent years. However, studies have been undertaken in isolation with minimal collaboration and exploration of the relationships between air, deposition and dust. This review collates concentrations (particle count and mass-based), shape, size and polymetric characteristics for microplastics in ambient air (m3), deposition (m2/day), dust (microplastics/g) and snow (microplastics/L) from 124 peer-reviewed articles to provide a holistic overview and analysis of our current knowledge. In summary, ambient air featured concentrations between <1 to >1000 microplastics/m³ (outdoor) and <1 microplastic/m³ to 1583 ± 1181 (mean) microplastics/m³ (indoor), consisting of polyethylene terephthalate, polyethylene, polypropylene. No difference (p > 0.05) was observed between indoor and outdoor concentrations or the minimum size of microplastics (p > 0.5). Maximum microplastic sizes were larger indoors (p < 0.05). Deposition concentrations ranged between 0.5 and 1357 microplastics/m²/day (outdoor) and 475 to 19,600 microplastics/m²/day (indoor), including polyethylene, polystyrene, polypropylene, polyethylene terephthalate. Concentrations varied between indoor and outdoor deposition (p < 0.05), being more abundant indoors, potentially closer to sources/sinks. No difference was observed between the minimum or maximum reported microplastic sizes within indoor and outdoor deposition (p > 0.05). Road dust concentrations varied between 2 ± 2 and 477 microplastics/g (mean), consisting of polyvinyl chloride, polyethylene, polypropylene. Mean outdoor dust concentrations ranged from <1 microplastic/g (remote desert) to between 18 and 225 microplastics/g, comprised of polyethylene terephthalate, polyamide, polypropylene. Snow concentrations varied between 0.1 and 30,000 microplastics/L, containing polyethylene, polyamide, polypropylene. Concentrations within indoor dust varied between 10 and 67,000 microplastics/g, including polyethylene terephthalate, polyethylene, polypropylene. No difference was observed between indoor and outdoor concentrations (microplastics/g) or maximum size (p > 0.05). The minimum size of microplastics were smaller within outdoor dust (p > 0.05). Although comparability is hindered by differing sampling methods, analytical techniques, polymers investigated, spectral libraries and inconsistent terminology, this review provides a synopsis of knowledge to date regarding atmospheric microplastics.

Enhancing the environmental monitoring of pesticide residues through Apis mellifera colonies: Honey bees versus passive sampling

The use of apicultural matrices for the environmental monitoring of pesticides is a widely employed approach that facilitates to a great extent the sampling procedures. Honey bees are one of the most commonly employed matrices in these studies due to their abundance in the colonies and their direct contact with the beehive and the environment. However, the analysis of this matrix is associated to a lack of representativity of the contaminants accumulated within the beehive, due mainly to the limited number of honey bees that are sampled and analyzed compared to the population in a hive. This small proportion of organisms which are sampled from the colony may lead to underestimations or overestimations of the total pesticide load, depending on the specific individuals that are included in the analysis. In the present work, the passive, non-invasive APIStrip-based sampling approach is compared to active bee sampling with a total of 240 samples taken from 15 apiaries from Austria, Denmark and Greece over a two-month period in 2022. The APIStrips have been found to provide a more comprehensive image of the pesticide residues accumulated in the beehive in terms of number of identified residues and robustness of the results. A total of 74 different pesticide residues were detected: the use of APIStrips allowed to detect 66 pesticides in the three countries, compared to 38 residues in honey bees. The use of APIStrips also resulted in a higher percentage of positive samples (containing at least one pesticide residue). The results provided by the passive sampling approach were also more consistent among the replicates and over time, which reveals an increased sampling robustness.

Microplastics and Nanoplastics Effects on Plant-Pollinator Interaction and Pollination Biology

Microplastics and nanoplastics (MNPs) contamination is an emerging environmental and public health concern, and these particles have been reported both in aquatic and terrestrial ecosystems. Recent studies have expanded our understanding of the adverse effects of MNPs pollution on human, terrestrial, and aquatic animals, insects, and plants. In this perspective, we describe the adverse effects of MNPs particles on pollinator and plant health and discuss the mechanisms by which MNPs disrupt the pollination process. We discuss the evidence and integrate transcriptome studies to investigate the negative effects of MNPs on the molecular biology of pollination, which may cause delay or inhibit the pollination services. We conclude by addressing challenges to plant-pollinator health from MNPs pollution and argue that such harmful effects disrupt the communication between plant and pollinator for a successful pollination process.

Effects of chlorination on microplastics pollution: Physicochemical transformation and chromium adsorption

The large number of microplastics (MPs) that appear in the environment has drawn much attention. Few studies, however, have examined the transformation of MPs in water treatment processes and their effects on environmental pollutants. In this study, the alteration of the physicochemical characteristics of polyethylene and thermoplastic polyurethane upon chlorination, as well as the influence of this alteration on contaminants, were investigated. The findings indicated that microplastics underwent significant morphology and O-functional groups changes during chlorination. It is noteworthy that the mechanisms controlling the chlorination treatment of the two MPs are clearly different. The results of aggregation and adsorption experiments showed that the chlorination treatment enhanced the aggregation ability of the MPs in brine and their interaction with Cr(VI). The present discoveries further suggested that water treatment could alter the migration capacity of microplastics and the distribution of contaminants in the aqueous environment by altering the adsorption of microplastics to the contaminants.

Mobile samplers of particulate matter - Flying omnivorous insects in detection of industrial contamination

Flying insects are potential mobile samplers of airborne particulate matter (PM). However, current knowledge on their susceptibility to PM is limited to pollinators. Insects' capacity for particle surface accumulation depends on the lifestyle, structure of the body integuments, and behavioral patterns. Here, we investigate how two species of flying omnivorous insects from the genus Vespula, possessing direct interactions with air, soil, plants, and herbivores, indicate industrial pollution by accumulating coarse (PM₁₀) and fine (PM_2.5) particles on their bodies. The internal accumulation of particles in wasps' gut tissues is assessed considering heavy metals exposure to reveal and discuss the potential magnitude of ecotoxicological risks. Female individuals of Vespula vulgaris and V. germanica were sampled with a hand-netting near to Harjavalta Cu-Ni smelter and in the control areas in southwestern Finland. They were analyzed with light microscopy (LM), electron microscopy (SEM, TEM), and energy-dispersive X-ray spectroscopy (EDX) methods. Near to the smelter, wasps trapped significantly more particles, which were of bigger size and their surface optical density was higher. Vespula vulgaris accumulated larger particles than V. germanica, but that wasn't associated with morphological characteristics such as body size or hairiness. In both areas, accumulated surface PM carried clays and silicates. Only in polluted environments PM consistently contained metallic and nonmetallic particles (from high to moderate weight %) of Fe, Ni, Cu, and S - major pollutants emitted from the smelter. Wasps from industrially polluted areas carried significantly more granules in the columnar epithelial midgut cells. TEM-EDX analyses identified those structures were associated with metal ions such as Cr, Cu, Ni, and Fe. As epithelial gut cells accumulated metal particles, midgut confirmed as a barrier for metal exposure in wasps. External PM contamination in wasps is suggested as a qualitative, yet a natural and simple descriptor of local industrial emissions.

Ingestion of polystyrene microparticles impairs survival and defecation in larvae of Polistes satan (Hymenoptera: Vespidae)

Microplastics (MPs) are widespread pollutants of emerging concern, and the risks associated with their ingestion have been reported in many organisms. Terrestrial environments can be contaminated with MPs, and terrestrial organisms, including arthropods, are predisposed to the risk of ingesting MPs. In the current study, the larvae of the paper wasp Polistes satan were fed two different doses (6 mg or 16 mg at once) of polystyrene MPs (1.43 mm maximum length), and the effects of these treatments on immature development and survival till adult emergence were studied. Ingestion of the two doses resulted in mortality due to impaired defecation prior to pupation. The survival of larvae that ingested 16 mg of MPs was significantly lower than that of the control. The ingestion of 16 mg of MPs also reduced the adult emergence (11.4%) in comparison to the control (44.4%). MPs were not transferred from the larvae to the adults that survived. These findings demonstrate that MP ingestion can be detrimental to P. satan, e.g. larval mortality can decrease colony productivity and thus the worker force, and that MPs can potentially affect natural enemies that occur in crops, such as predatory social wasps.

Microplastics incorporated by honeybees from food are transferred to honey, wax and larvae

Microplastics (MP) are ubiquitous in the environment, and there is little information available on their impact on terrestrial organisms. Their effect on insects and particularly on honeybees is relevant, given the prevalence of these organisms in the environment and the fact that they provide key ecosystem services. We conducted a field study to assess (1) the fate of these ingested MP within the hive, and (2) MP effect on Apis mellifera population growth during chronic exposure. We aimed to determine if MP ingested by honeybees are incorporated into hive matrices, including honey, and their effect on colony development and honey reserves. We fed beehives with sucrose solutions treated or untreated with 50 mg of Polyester microfibers/L for one month. Microplastic fibers (MF) from treated syrup were incorporated by adult worker bees, remaining in their cuticle, digestive tract, larvae, honey, and wax. Most of the MF were accumulated in wax showing that honey remains as a safe food. At the end of the experiment, no differences in honey reserves or bee population were observed. This is the first study to evaluate in the field the effects and dynamics of MP inside honeybee hives. Our results showed that bees can incorporate MP from the environment and deliver them into the different matrices of the hive. Concentration of MF found in honey of treated hives was like that found in commercial honey, suggesting that honeybees might be exposed to similar MP contamination levels in the environment compared to our experiment. Finally, our results highlight a way in which MP might enter the food chain, with direct implication for human health.

Insects and Public Health: An Overview

Insects are, by far, the most common animals on our planet. The ubiquity and plethora of ecological niches occupied by insects, along with the strict and sometimes forced coexistence between insects and humans, make insects a target of public health interest. This article reports the negative aspects historically linked to insects as pests and vectors of diseases, and describes their potential as bioindicators of environmental pollution, and their use as food and feed. Both negative and positive impacts of insects on human and animal health need to be addressed by public health professionals who should aim to strike a balance within the wide range of sometimes conflicting goals in insect management, such as regulating their production, exploiting their potential, protecting their health and limiting their negative impact on animals and humans. This requires increased insect knowledge and strategies to preserve human health and welfare. The aim of this paper is to provide an overview of traditional and emerging topics bridging insects and public health to highlight the need for professionals, to address these topics during their work. The present and future role and activities of public health authorities regarding insects are analyzed.

Contaminant Cocktails of High Concern in Honey: Challenges, QuEChERS Extraction and Levels

Environmental pollution is a crucial problem in our society, having nowadays a better understanding of its consequences, which include the increase of contaminant cocktails present in the environment. The contamination of honeybees can occur through their interaction with the nearby environment. Therefore, if honeybees are previously contaminated, there is a possibility of contamination of their products, such as honey as natural, or minimally processed, product, resulting from the honeybees’ activity. Considering that honey is a highly consumed product, it is extremely necessary to control its quality and safety, including evaluating the presence and quantification of contaminants, which should follow monitoring studies and the legislation established by the European Union. This work aims to review the literature of different contaminants reported on honey, including pesticides, persistent organic pollutants, polycyclic aromatic hydrocarbons, and pharmaceuticals, focusing on the reports using the QuEChERS technique for the extraction. Furthermore, reports of microplastics on honey samples were also discussed. Despite the existence of several methods that identify and quantify these contaminants, few methods have been reported to operate with different groups of contaminants simultaneously. The development of methods with this characteristic (while being fast, low cost, and with a lower impact on the environment), monitoring studies to identify the risks, and an update on legislation are priority actions and future perspectives to follow.

Microplastics: A Real Global Threat for Environment and Food Safety: A State of the Art Review

Microplastics are small plastic particles that come from the degradation of plastics, ubiquitous in nature and therefore affect both wildlife and humans. They have been detected in many marine species, but also in drinking water and in numerous foods, such as salt, honey and marine organisms. Exposure to microplastics can also occur through inhaled air. Data from animal studies have shown that once absorbed, plastic micro- and nanoparticles can distribute to the liver, spleen, heart, lungs, thymus, reproductive organs, kidneys and even the brain (crosses the blood-brain barrier). In addition, microplastics are transport operators of persistent organic pollutants or heavy metals from invertebrate organisms to other higher trophic levels. After ingestion, the additives and monomers in their composition can interfere with important biological processes in the human body and can cause disruption of the endocrine, immune system; can have a negative impact on mobility, reproduction and development; and can cause carcinogenesis. The pandemic caused by COVID-19 has affected not only human health and national economies but also the environment, due to the large volume of waste in the form of discarded personal protective equipment. The remarkable increase in global use of face masks, which mainly contain polypropylene, and poor waste management have led to worsening microplastic pollution, and the long-term consequences can be extremely devastating if urgent action is not taken.

Chronic Exposure to Polystyrene Microplastic Fragments Has No Effect on Honey Bee Survival, but Reduces Feeding Rate and Body Weight

Microplastics (MPs), in the form of fragments and fibers, were recently found in honey samples collected in Ecuador as well as in honey bees collected from Denmark and China. However, little is known about how MPs impact bee health. To fill this knowledge gap, we investigated the potential toxicity of irregularly shaped polystyrene (PS)-MP fragments on honey bee health. In the first experiment of its kind with honey bees, we chronically exposed bees with a well-established gut microbiome to small (27 ± 17 µm) or large (93 ± 25 µm) PS-MP fragments at varying concentrations (1, 10, 100 µg mL^-1) for 14 days. Bee mortality, food consumption, and body weight were all studied. We found that chronic exposure to PS-MP fragments has no effect on honey bee survival, but reduced the feeding rate and body weight, particularly at 10 µg PS-MP fragments per mL, which may have long-term consequences for honey bee health. The findings of this study could assist in the risk assessment of MPs on pollinator health.

Microplastics and plastics-associated contaminants in food and beverages; Global trends, concentrations, and human exposure

Microplastics has become a global concern due to their ubiquitous presence which poses unavoidable human exposure risks. Geographical distribution and yearly trends of research on microplastics, food, and beverages do not exist. Thus, no overall account is available regarding the presence of microplastics and plastics-associated contaminants in food and beverages. Hence, this attempt is to review the geographical distribution of studies through a brief bibliometric analysis and the plastics-associated contaminants including plasticizers and microplastics in food and beverages. Estimated microplastic consumption has been listed for the pool of publications reviewed here. Further, this review discusses the ingestion potency of micropollutants associated with microplastics, possible health impacts, and existing challenges. Global trend in research exponentially increased after 2018 and China is leading. Studies on microplastics were limited to a few beverages and food; milk, beer, tea, refreshing drinks, salt, sugar, honey, etc., whereas seafood and drinking water have been extensively studied. Publications on plastic-additives were reported in two ways; migration of plastic-additives from packaging by leaching and the presence of plastic-additives in food and beverages. Bisphenol A and bis(2-Ethylhexyl) phthalate were the most frequently reported both in food and beverages. Exposure of packaging material to high temperatures predominantly involves plastic-additive contamination in food and beverages. Microplastics-bound micropollutants can also be ingested through food and beverages; however, a lack of knowledge exists. The complex matrix of food or beverages and the absence of standard procedures for analysis of microplastics and micropollutants exist as challenges. More investigations on the presence of microplastics and plastic-additives in food and beverage are urgent needs to a better assessment of potential human exposure and human health risk.

Microplastics Derived from Food Packaging Waste-Their Origin and Health Risks

Plastics are commonly used for packaging in the food industry. The most popular thermoplastic materials that have found such applications are polyethylene (PE), polypropylene (PP), poly(ethylene terephthalate) (PET), and polystyrene (PS). Unfortunately, most plastic packaging is disposable. As a consequence, significant amounts of waste are generated, entering the environment, and undergoing degradation processes. They can occur under the influence of mechanical forces, temperature, light, chemical, and biological factors. These factors can present synergistic or antagonistic effects. As a result of their action, microplastics are formed, which can undergo further fragmentation and decomposition into small-molecule compounds. During the degradation process, various additives used at the plastics' processing stage can also be released. Both microplastics and additives can negatively affect human and animal health. Determination of the negative consequences of microplastics on the environment and health is not possible without knowing the course of degradation processes of packaging waste and their products. In this article, we present the sources of microplastics, the causes and places of their formation, the transport of such particles, the degradation of plastics most often used in the production of packaging for food storage, the factors affecting the said process, and its effects.

Thrushes (Aves: Passeriformes) as indicators of microplastic pollution in terrestrial environments

Microplastic pollution is one of the leading global conservation issues. The aim of this study was to investigate the occurrence of microplastics in the gastrointestinal tracts of Common Blackbirds Turdus merula (N = 16) and Song Thrushes Turdus philomelos (N = 18), songbirds with exceptionally terrestrial lifestyles and a wide distribution range. We searched for microplastics of over 100 μm in size and assessed whether their contamination differed regarding the age of the birds and the time of year. We used birds that had died as a result of collision with anthropogenic infrastructure, which were sampled during wildlife monitoring of anthropogenic infrastructures and citizen science projects in north-eastern Poland. We found that all the analysed individuals contained microplastic in their gastrointestinal tracts, which were classified as fibers, fragments, films and pellets. A total number of 1073 microplastics were observed, mostly consisting of fibers (84 %) and films (10 %) below 1 mm in size. The dominant colours of microplastics were transparent (75 %) and brown (14 %). The species average microplastic concentration was higher in Song Thrushes (40.1) than Common Blackbirds (21.9), however the difference was not statistically significant. Moreover, we found no seasonal or age-related differences in microplastic ingestion in either species. While our results show a ubiquity of microplastics in terrestrial environments, they also indicate that thrushes have the potential to be used as indicators of microplastic pollution in terrestrial ecosystems.

Characterization and regulation of microplastic pollution for protecting planetary and human health

Microplastics are plastic particles <5 mm in diameter. Since the 1950s, there has been an exponential increase in the production of plastics. As of 2015, it is estimated that approximately 6300 million metric tons of plastic waste had been generated of which 79% has accumulated in landfills or the natural environment. Further, it is estimated that if current trends continue, roughly 12,000 million metric tons of plastic waste will accumulate by 2050. Plastics and microplastics are now found ubiquitously-in the air, water, and soil. Microplastics are small enough to enter the tissues of plants and animals and have been detected in human lungs, stools, placentas, and blood. Their presence in human tissues and the food chain is a cause for concern. While direct clinical evidence or epidemiological studies on the adverse effects of microplastic on human health are lacking, in vitro cellular and tissue studies and in vivo animal studies suggest potential adverse effects. With the ever-increasing presence of plastic waste in our environment, it is critical to understand their effects on our environment and on human health. The use of plastic additives, many of which have known toxic effects are also of concern. This review provides a brief overview of microplastics and the extent of the microplastic problem. There have been a few inroads in regulating plastics but currently these are insufficient to adequately mitigate plastic pollution. We also review recent advances in microplastic testing methodologies, which should support management and regulation of plastic wastes. Significant efforts to reduce, reuse, and recycle plastics are needed at the individual, community, national, and international levels to meet the challenge. In particular, significant reductions in plastic production must occur to curb the impacts of plastic on human and worldwide health, given the fact that plastic is not truly recyclable.

Fire releases micro- and nanoplastics: Raman imaging on burned disposable gloves

Raman imaging can effectively characterise microplastics and nanoplastics, which is validated here to capture the items released from the plastic gloves when subjected to a mimicked fire. During the COVID-19 pandemic, large quantities of personal protective equipment (PPE) units have been used, such as the disposable gloves. If discarded and poorly managed, plastics gloves might break down to release secondary contaminants. The breakdown process can be accelerated by burning in a bushfire or at the incineration plants. During the burning process, the functional groups on the surface can be burned differently due to their different thermal stabilities. The different degrees of burning can be distinguished and visualised via Raman imaging. In the meantime, at the bottom of the burned plastics, microplastics and nanoplastics can be generated at a significant amount. The possible false Raman imaging on microplastics and nanoplastics is also discussed, by effectively extracting and distinguishing the weak signal from the background or noise. Overall, these findings confirm the importance of effectively working waste incineration plants and litter prevention, and suggest that Raman imaging is a suitable approach to characterise microplastics and nanoplastics.

Microplastics in ASEAN region countries: A review on current status and perspectives

A literature assessment was conducted to determine the current state of microplastics research in ASEAN countries focusing on 1) microplastics in water, sediment, and water organisms; 2) microplastics' sources and dispersion; and 3) microplastics' environmental consequences, including human toxicity. ASEAN countries contributed only about 5 % of the global scholarly papers on microplastics, with Indonesia contributing the most followed by Malaysia and Thailand. The lack of standard harmonized sampling and processing methodologies made comparisons between research difficult. ASEAN contributes the most to plastic trash ending up in the ocean, indicating a need for more work in this region to prevent plastic pollution. Microplastics are found in every environmental compartment; however, their distribution and environmental consequences have not been sufficiently investigated. There are very few studies on microplastics in the human blood system as well as respiratory organs like the lungs, indicating that more research is needed.

Food and human safety: the impact of microplastics

Plastic waste pollution is one of the biggest problems in the world today. The amount of plastic in the environment continues to increase, and human exposure to microplastic (MP) has become a reality. This subject has attracted the attention of the whole world. The MP problem has also been noticed by the scientific community. The term microplastic is mostly used to define synthetic material with a high polymer content that can have a size range from 0.1 to 5000 µm. This paper aims to characterize the routes of exposure to MP, define its pollution sources, and identify food types contaminated with plastics. This review addresses the current state of knowledge on this type of particles, with particular emphasis on their influence on human health. Adverse effects of MP depend on routes and sources of exposure. The most common route of exposure is believed to be the gastrointestinal tract. Sources of MP include fish, shellfish, water as well as tea, beer, wine, energy drinks, soft drinks, milk, salt, sugar, honey, poultry meat, fruits, and vegetables. Studies have shown that particles of PET, PE, PP, PS, PVC, PA, and PC are the most frequently found in food.

Nano- and micro-polystyrene plastics disturb gut microbiota and intestinal immune system in honeybee

Micro- (MPs) and nano-plastics (NPs) have become emerging pollutants in the environment. Their wide distribution and capacity as a vector of hazardous materials threaten various organisms. Honeybees have been used as bioindicators for pollutants as their gut microbiota offers advantages for addressing how it alters the host health and exploring the processes of environmental pollutants affecting gut community dynamics. In this study, the effects of plastic particles of different sizes on honeybees' health were investigated. Oral exposure to polystyrene (PS) particles with a diameter of 100 nm significantly decreased the whole-body weight and survival rate of honeybees and induced intestinal dysplasia. As the increase of the feeding time from Day 0 to Day 15, the MPs moved to and accumulated in the rectum, where most bee gut symbionts colonized. Scanning electron microscope observation showed that 100-nm PS particles adhered to the germination pore of pollen, while 1- and 10-μm PS particles were attached by gut bacteria. We found that 100-nm PS treatment decreased the relative abundance of Lactobacillus and Bifidobacterium in the guts. Correspondingly, PS treatment stimulated immune inhibitory genes and depressed genes related to detoxification and energy balance. Furthermore, 100-nm PS treated honeybees became more susceptible to the pathogenic Hafnia alvei, leading to a five-times higher mortality rate. These results indicated the adverse impacts of NPs on honeybees, which extends our knowledge regarding the emerging health risks of plastic debris, especially at the nanoscale.

Man-made natural and regenerated cellulosic fibres greatly outnumber microplastic fibres in the atmosphere

Atmospheric microplastics have been widely reported in studies around the world. Microfibres are often the dominant morphology found by researchers, although synthetic (i.e., plastic) microfibres are typically just a fraction of the total number of microfibres, with other, non-synthetic, cellulosic microfibres frequently being reported. This study set out to review existing literature to determine the relative proportion of cellulosic and synthetic atmospheric anthropogenic (man-made) microfibres, discuss trends in the microfibre abundances, and outline proposed best-practices for future studies. We conducted a systematic review of the existing literature and identified 33 peer-reviewed articles from Scopus and Google Scholar searches that examined cellulosic microfibres and synthetic microfibres in the atmosphere. Multiple analyses indicate that cellulosic microfibres are considerably more common than synthetic microfibres. FT-IR and Raman spectroscopy data obtained from 24 studies, showed that 57% of microfibres were cellulosic and 23% were synthetic. The remaining were either inorganic, or not determined. In total, 20 studies identified more cellulosic microfibres, compared to 11 studies which identified more synthetic microfibres. The data show that cellulosic microfibres are 2.5 times more abundant between 2016 and 2022, however, the proportion of cellulosic microfibres appear to be decreasing, while synthetic microfibres are increasing. We expect a crossover to happen by 2030, where synthetic microfibres will be dominant in the atmosphere. We propose that future studies on atmospheric anthropogenic microfibres should include information on natural and regenerated cellulosic microfibres, and design studies which are inclusive of cellulosic microfibres during analysis and reporting. This will allow researchers to monitor trends in the composition of atmospheric microfibers and will help address the frequent underestimation of cellulosic microfibre abundance in the atmosphere.

Acute and chronic ingestion of polyethylene (PE) microplastics has mild effects on honey bee health and cognition

The massive use of plastic has contributed to huge quantities of hazardous refuse at a global scale and represents one of the most prominent issues of the Anthropocene. Microplastics (MPs) have been detected in almost all environments and pose a potential threat to a variety of plant and animal species. Many studies have reported a variety of effects, from negligible to detrimental, of MPs to aquatic organisms. Conversely, much less is known about their effect on terrestrial biota, and particularly on animal behavior and cognition. We assessed the oral toxicity of polyethylene (PE) MPs at three different concentrations (0.5, 5, and 50 mg L^-1), and at different timescales (1 day and 7 days of exposure) and tested for their effects on survival, food intake, sucrose responsiveness, habituation to sucrose and appetitive olfactory learning and memory in the honey bee Apis mellifera. We found that workers were not completely unaffected by acute and prolonged ingestion of this polymer. A significant effect of PE on bee mortality was found for the highest concentration but not for lower ones. PE affected feeding behavior in a concentration-dependent manner, with bees consuming more food than controls when exposed to low concentration PE. Regarding our behavioral and cognitive experiments, the high concentration PE was found to affect only bees' ability to respond consistently to sucrose but not sucrose sensitivity, habituation to sucrose or learning and memory abilities, even for prolonged exposure to PE. While these last results may look somewhat encouraging, we discussed why caution is warranted before ruling out the possibility that PE particles at environmental concentrations are harmful to honey bees.

A Simple Sample Preparation Method to Significantly Improve Fourier Transform Infrared (FT-IR) Spectra of Microplastics

Spectroscopic analysis has become an essential part of the rapidly growing field of microplastic (MP) research. Here, we introduce a simple sample preparation method that dramatically improves results from Fourier transform infrared (FT-IR) analysis of MP and other environmental fibers. Our method provides cost-effective, reliable, high-quality spectra that achieve high-matching scores to polymer libraries. The efficacy of this method is demonstrated with two environmental datasets from Singapore and Phnom Penh that were collected while sampling for atmospheric MPs. The method developed and applied in this study is a simplification of the KBr method, where the analyzed fiber is pressed to a thickness of <10 μm; however, no KBr powder is required. For the combined dataset, 379 non-pressed fibers were analyzed with 193 (51%) returning a search score of ≥80% (chosen minimum search score threshold) and 259 pressed fibers, with 254 (98%) returning a search score of ≥80%. Direct comparisons of fibers before and after pressing show that the highest individual search score, and average search score from multiple single-point measurements, is overwhelmingly higher following our method. Our method immobilizes and improves the surface of the fiber, by creating a wider and uniform area for measurements. For FT-IR operators, this saves considerable time, improves reliability of the analysis, and, importantly, provides reproducibility of the spectra generated.

The polymers and their additives in particulate plastics: What makes them hazardous to the fauna?

Due to the increasing concerns on global ecosystems and human health, the environmental risks posed by microplastics (MPs) and nanoplastics (NPs) have become an important topic of research. Their ecological impacts on various faunal species have been extensively researched and reviewed. However, the majority of those studies perceive these micro(nano)-plastics (MNPs) as a single entity rather than a collective term for a group of chemically distinct polymeric particulates. Each of the plastic polymers can possess unique physical and chemical behavior, which, in turn, can determine the possible environmental impacts. Furthermore, many studies explore the adsorption, absorption, and release of other environmental pollutants by MNPs. But only a handful of them explore the leaching of additives possessed by these polymers. Data on the environmental behavior and toxicity of individual additives associated with different polymer particulates are scarce. Knowledge about the leachability and ecotoxicity of the additives associated with environmental MNPs (unlike large plastic particles) remains limited. The ecological impacts of different MNPs together with their additives and the basis of their toxicity have not been explored yet. The present review systematically explores the potential implications of environmentally predominant polymers and their associated additives and discusses their physicochemical characteristics. The review ultimately aims to provide novel insights on what components precisely make MNPs hazardous to the fauna. The paper also discusses the major challenges proposed in the available literature along with recommendations for future research to throw light on possible solutions to overcome the hazards of MNPs.