Microplastics-sorbed phenanthrene and its derivatives are highly bioaccessible and may induce human cancer risks

Adsorption and desorption of phenanthrene and 1-hydroxyphenanthrene by goethite-coated polyvinyl chloride

Microplastics loaded with phenanthrene and derivatives are widely detected in aquatic environments, and the coating of natural minerals or organic macromolecules may change the environmental behavior of microplastics. In this study, three kinds of composites with different coverage were prepared by coating goethite on the surface of polyvinyl chloride microplastics to investigate the adsorption and desorption behavior of phenanthrene (PHE) and 1-hydroxyphenanthrene (1-OHPHE), and the effect of mucin on desorption was investigated. The results showed that goethite promoted the adsorption of PHE and 1-OHPHE by increasing the specific surface area of the composites. With the increase of the cover degree, the adsorption of PHE decreased because of the decrease in hydrophobicity; while the adsorption of 1-OHPHE initially increased and then decreased with the contributions of hydrophobic interaction and hydrogen bond. The adsorption of 1-OHPHE could be influenced by the pH and ionic strength primarily through electrostatic interactions and Ca2+ bridging. The goethite significantly increased the desorption hysteresis for two chemicals due to the complicated pore structures and increased adsorption affinity. Mucin promoted the desorption of PHE through competitive adsorption, and inhibit the desorption of 1-OHPHE through hydrophobic interaction, hydrogen bonding and Ca2+ bridging. This study elucidated the effects of natural minerals on the adsorption and desorption behavior of organic pollutants on microplastics, briefly discussed the effects of organic macromolecules on the desorption behavior of pollutants with different properties, and emphasized the different environmental behaviors of pollutants.

Health risk assessment of microplastics contamination in the daily diet of South Asian countries

South Asian countries face a major threat concerning microplastics (MPs) contamination in food. This study explores the existing evidence of MPs in major foods of South Asian countries and links with available health risk indices through meta-analysis. Overall range of MPs in treated water, bottled water, fish, milk, salt, wheat, rice, and sugar were 0.75-35.33 particles L-1, 0.07-500 particles L-1, 0.006-361.6 particles g-1, 11.1-295.5 particles L-1, 0.01-350 particles g-1, 4.57 particles g-1, 0.303 particles g-1 and 0.343 particles g-1, respectively. Daily intake of MPs through food items was estimated with a range of 508-2280 particles person-1 day-1 depending on age group. Hazard score of MPs contaminated food indicates high to very high hazard scores in salt with an average PHI of 10,817.6 followed by fish (9012.9), milk (4900.4) and drinking water (3752.9) which are higher than the global values. High-risk polymers include Polyvinyl Chloride, Polyacrylamide, Styrene-Butadiene copolymer, Polyester, Polyurethane, and Polyamide. Average rate of microplastics ingestion ranged between 0.64 and 36.3 g person-1 year-1 with fish stand apex followed by bottled water, salt and milk. This study further investigates research gaps on MPs contamination in the foods of South Asian countries. Overall, the present study summarised the present level of MPs ingestion through different food sources in South Asian countries, highlighting the need for strong regulation to monitor level of MPs contamination in food.

Microplastic pollution: Critical analysis of global hotspots and their impact on health and ecosystems

This paper examines microplastic hotspots and their drastic effects on human health and the environment pointing out microplastic pollution as one of the biggest global issues. Besides, it analyses the key sources including industrial effluent discharge, littered plastic wastes, and deterioration of synthetic products together with pathways and routes of exposure. The review also focuses on microplastic contamination in food systems such as meat, plant-based products, dairy, and seafood, detailing their entry into the food chain via soil, water, and air. On the other hand, this work also focuses on human health issues including cellular absorption, and bioaccumulation, which results in tissue oxidative stress, inflammation, hormonal imbalance and adverse long-term effects, including carcinogenicity and organ toxicity. The ultimate effects of microplastic pollution on the condition of the soil, water, and fauna and flora of the ecosystem, highlighting on the need for the prevention measures, were also addressed. This paper seeks to critically ascertain the problems posed by microplastics, including their slow biodegradation limit, the absence of proper regulations, and lack of a universally accepted standard. It also highlights that microplastic pollution requires interdisciplinary analyses, future studies, and high standards-compliant policies and regulations. This work raises the alarm for a collective international effort to protect the public health, food, and the earth.

Unraveling microplastic behavior in simulated digestion: Methods, insights, and standardization

Despite the rapid expansion of in vitro digestion studies on microplastics (MPs), the field remains fragmented due to inconsistent methodologies, varying analytical approaches, and a lack of standardized protocols. These discrepancies hinder cross-study comparisons, complicate risk assessments, and limit the applicability of in vitro models for understanding MP fate and pollutant interactions in the gastrointestinal environment. A comprehensive synthesis is needed to assess progress, identify research gaps, and establish a unified research direction. This review systematically evaluates 85 studies (2020-2024), consolidating key findings and methodological challenges. It examines disparities in digestion protocols, fluid compositions, and exposure conditions, assessing how factors such as pH, enzyme activity, residence time, and temperature shape MPs' behavior and physicochemical transformations. Key findings on bio-corona formation, structural modifications, contaminant bioaccessibility, and interactions with digestive enzymes are synthesized to provide a clearer picture of MP behavior during digestion. With the field remains dominated by studies on polystyrene and polyethylene MPs in human-based models, inconsistencies persist, highlighting the urgent need for standardized methodologies. By addressing these gaps, this review lays a critical foundation for improving reproducibility, advancing standardization efforts, and strengthening exposure assessments, ultimately enhancing our understanding of MP ingestion risks to human health.

Understanding the seasonal variation of the microplastics occurrence and source in the water source: upstream of the Huangpu River in Shanghai as an example

The potential seasonal variations in the features and sources of microplastics (MPs) in reservoirs and the connected upstream rivers remain poorly understood. A field study of MPs in Huangpu River upper reaches indicated that surface water MP abundance was 4.75 ± 0.63 (Taipu River), 5.8 ± 0.9 (Lanlugang River), and 4.3 ± 0.9 items/L (Jinze Reservoir) during wet season, increasing to 12.9 ± 1.4, 18 ± 1.7, and 8.3 ± 1.7 items/L, respectively in drought season, whereas in sediment was 6704 ± 421, 3932 ± 200, and 4737 ± 408 items/kg during wet season, which decreased to 4045 ± 523, 4017 ± 430, and 2229 ± 434 items/kg during drought period. The MPs mainly comprised PE, PP fragments/fibers, and PET fibers. The significant seasonal variations in MP abundance were detected only within the surface water and sediments of rivers. Notably, significant seasonal variations in the features of MPs were observed in the surface water of Jinze Reservoir and the surface water or the sediments of rivers. During the wet season, multiple potential sources of MPs were identified in the reservoir, whereas the Taipu River served as the primary source during drought periods. Moderate or lower MP abundance was observed within the surface water of upper reaches of the Huangpu River, while higher levels were found in the sediments. The findings suggest Jinze Reservoir's MP control requires seasonal adjustments. While upper Huangpu River surface water shows lower risk with good safety, MP migration to sediments elevates risks, necessitating prioritized sediment management.

Environmental toxicology of microplastic particles on fish: A review

The increase in plastic debris and its environmental impact has been a major concern for scientists. Physical destruction, chemical reactions, and microbial activity can degrade plastic waste into particles smaller than 5 mm, known as microplastics (MPs). MPs may eventually enter aquatic ecosystems through surface runoff. The accumulation of MPs in aquatic environments poses a potential threat to finfish, shellfish, and the ecological balance. This study investigated the effect of MP exposure on freshwater and marine fish. MPs could cause significant harm to fish, including physical damage, death, inflammation, oxidative stress, disruption of cell signalling and cellular biochemical processes, immune system suppression, genetic damage, and reduction in fish growth and reproduction rates. The activation of the detoxification system of fish exposed to MPs may be associated with the toxicity of MPs and chemical additives to plastic polymers. Furthermore, MPs can enhance the bioavailability of other xenobiotics, allowing these harmful substances to more easily enter and accumulate in fish. Accumulation of MPs and associated chemicals in fish can have adverse effects on the fish and humans who consume them, with these toxic substances magnifying as they move up the food chain. Changes in migration and reproduction patterns and disruptions in predator-prey relationships in fish exposed to MPs can significantly affect ecological dynamics. These interconnected changes can lead to cascading effects throughout aquatic ecosystems. Thus, implementing solutions like reducing plastic production, enhancing recycling efforts, using biodegradable materials, and improving waste management is essential to minimize plastic waste and its environmental impact.

Polystyrene nanoplastics promote colitis-associated cancer by disrupting lipid metabolism and inducing DNA damage

Nanoplastics (NPs) have attracted widespread attention owing to their presence in the body. Recent studies highlighted the detrimental effects of NPs on the digestive tract. However, no studies have reported an association between NPs exposure and colitis-associated cancer (CAC). An azoxymethane/dextran sodium sulfate-induced CAC model was used, and polystyrene nanoparticles (PS-NPs) were selected for long-term exposure. Non-targeted metabolomics and 16S rRNA sequencing were used to detect changes in colonic metabolites and gut microbes following PS-NPs exposure. A lipopolysaccharide (LPS)-treated cancer cell model (Caco-2) exposed to PS-NPs was used to investigate the underlying molecular mechanism. Compared to the normal control group, mice in the PS-NPs group exhibited more tumor nodes and reactive oxygen species (ROS), higher expression of pan-CK and Ki-67, and more severe DNA damage. 16S rRNA sequencing revealed that exposure to PS-NPs altered the abundance of Allobaculum and Lactobacillus, whereas metabolic analysis showed that the most significant metabolites were enriched mostly in fatty acid metabolism. Experiments in LPS intervened Caco-2 cells showed that exposure to PS-NPs led to lipid peroxidation, oxidative stress, and DNA damage in Caco-2. Exposure to PS-NPs activated the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway both in the AOM/DSS mouse model and cellular model. Key proteins involved in fatty acid metabolism were downregulated in Caco-2 cells exposed to PS-NPs. The metabolic effects of cancer cells exposed to PS-NPs were significantly inhibited by the activation of the fatty acid metabolism pathway by fenofibrate. PS-NPs exposure disturbed lipid metabolism and induced DNA damage via the activation of PI3K/AKT/mTOR to promote CAC progression. Inhibition of fatty acid metabolism is a therapeutic target for controlling PS-NP-induced CAC. Our study provides an important reference for the prevention and treatment of CAC from the perspective of the environment and enhances awareness of the necessity of plastic control.

Long-term exposure of human U87 glioblastoma cells to polyethylene microplastics: Investigating the potential cancer progression

Precancerous cells are present in all human bodies. Various environmental triggers can promote the development of cancer. Microplastics, an emerging concern, may potentially act as one such trigger, contributing to cancer initiation or progression. Studies have confirmed the presence of microplastics within the human body. This raises concerns about their potential toxicity and health risks. In the present study, we aimed to investigate the impact of polyethylene microplastics (PE-MPs) within the size range of 37-75 microns on glioblastoma cancer cells. Initially, we assessed the short-term effects of six different concentrations of PE-MPs (20 mg/mL, 10 mg/mL, 5 mg/mL, 2.5 mg/mL, 1.25 mg/mL, and 0.62 mg/mL) on the U87 glioblastoma cell line. The results demonstrated that PE-MPs exposure led to an increase in cell proliferation compared to the untreated control group. Based on these findings, we decided to further explore the long-term effects of PE-MPs on U87 cancer cells. To evaluate the long-term effects, U87 glioblastoma cells were continuously exposed to 0.005 g of PE-MPs over an extended period of 26 days. Chronic exposure to PE-MPs significantly increased the proliferative and migratory capacities of U87 cells compared to the unexposed control group. Furthermore, continuous PE-MPs exposure altered the behavior and morphological characteristics of U87 cells. These cells exhibited a propensity to aggregate and form colonies within the culture flask. The formation of spheroid structures was also observed in the PE-MPs-exposed cell population. The results of this research indicate that polyethylene microplastics can promote the progression of glioblastoma cancer.

Microplastics in the Human Body: Exposure, Detection, and Risk of Carcinogenesis: A State-of-the-Art Review

Background: Humans cannot avoid plastic exposure due to its ubiquitous presence in the natural environment. The waste generated is poorly biodegradable and exists in the form of MPs, which can enter the human body primarily through the digestive tract, respiratory tract, or damaged skin and accumulate in various tissues by crossing biological membrane barriers. There is an increasing amount of research on the health effects of MPs. Most literature reports focus on the impact of plastics on the respiratory, digestive, reproductive, hormonal, nervous, and immune systems, as well as the metabolic effects of MPs accumulation leading to epidemics of obesity, diabetes, hypertension, and non-alcoholic fatty liver disease. MPs, as xenobiotics, undergo ADMET processes in the body, i.e., absorption, distribution, metabolism, and excretion, which are not fully understood. Of particular concern are the carcinogenic chemicals added to plastics during manufacturing or adsorbed from the environment, such as chlorinated paraffins, phthalates, phenols, and bisphenols, which can be released when absorbed by the body. The continuous increase in NMP exposure has accelerated during the SARS-CoV-2 pandemic when there was a need to use single-use plastic products in daily life. Therefore, there is an urgent need to diagnose problems related to the health effects of MP exposure and detection. Methods: We collected eligible publications mainly from PubMed published between 2017 and 2024. Results: In this review, we summarize the current knowledge on potential sources and routes of exposure, translocation pathways, identification methods, and carcinogenic potential confirmed by in vitro and in vivo studies. Additionally, we discuss the limitations of studies such as contamination during sample preparation and instrumental limitations constraints affecting imaging quality and MPs detection sensitivity. Conclusions: The assessment of MP content in samples should be performed according to the appropriate procedure and analytical technique to ensure Quality and Control (QA/QC). It was confirmed that MPs can be absorbed and accumulated in distant tissues, leading to an inflammatory response and initiation of signaling pathways responsible for malignant transformation.

First identification of microplastics in human uterine fibroids and myometrium

Microplastics (MPs) pollution has received widespread attention in recent years as the use of plastics continues to increase. However, currently no studies have reported the finding of MPs in human uterine fibroids (UFs) and myometrium tissues. In this study, UFs tissues (n = 48) and myometrium tissues (n = 40) from 48 patients and myometrium tissues (n = 8) from healthy population were collected. Following digestion of the samples by 10% KOH and 30% H2O2, MPs were analyzed qualitatively and quantitatively using Raman spectroscopy. The 16 UFs and myometrium tissue samples contained an average of 1.5 ± 1.17 MP particles per gram of tissue. Notably, the abundance of MPs in the UFs tissues (2.13 ± 1.17 particles per gram) was higher than in the myometrium tissues (0.88 ± 0.78 particles per gram). In the same cohort of individuals with UFs, the quantities of MPs detected in the affected UFs tissue (2.63 ± 1.77 particles per gram) exceeded those detected in healthy tissue (1.08 ± 0.93 particles per gram), particularly in elderly patients. A correlation was observed between elevated MP levels and frequent consumption of takeout meals and bottled water among patients, indicating that MP ingestion through food sources might have contributed to the increased abundance and variety of MPs within UFs. Furthermore, UFs increased in size with higher concentrations of MPs, which may have been related to elevated levels of MPs-induced hormones. This study provides new insights into the assessment of the relationship between exposure to MPs and human disease risk.

Detection and analysis of microplastics in tissues and blood of human cervical cancer patients

Microplastics (MPs) can enter the reproductive system and can be potentially harmful to human reproductive health. In this study, 13 types of microplastics (MPs) were identified in patient blood, cancer samples, and paracarcinoma samples using Raman spectroscopy, with polyethylene, polypropylene and polyethylene-co-polypropylene being the most abundant polymer types. Futher, cotton was also found in our study. The diversity and abundance of MPs were higher in blood samples than in cancerous tissues, and there was a significant positive correlation between diversity (p < 0.05). Furthermore, the diversity and abundance of MPs in cancerous tissues were higher than in paracancerous tissues. The dimensional sizes of MPs in these samples were also very similar, with the majority of detected MPs being smaller in size. Correlation analysis showed that patient's age correlated with the abundance of MPs in blood samples, body mass index (BMI) correlated with the abundance of MPs in cancerous tissues. Notably, the frequency with which patients consume bottled water and beverages may also increase the abundance of MPs. This study identifies for the first time the presence of MPs and cotton in cancerous and paracancerous tissues of human cervical cancer patients. This provides new ideas and basic data to study the risk relationship between MP exposure and human health.

Trophic transfer, bioaccumulation and translocation of microplastics in an international listed wetland on the Montreux record

Microplastics (MPs) are concerning emerging pollutants. Here, MPs in four edible aquatic species of different trophic levels (between ∼2 and 4), including fish species Esox lucius (Esocidae: Esocinae); Cyprinus carpio (Cyprinidae: Cyprininae); and Luciobarbus caspius (Cyprinidae: Barbinae); and the swan mussel Anodonta cygnea (Unionidae), were assessed in the Anzali freshwater ecosystem. It is a listed wetland in the Montreux record. MPs were extracted from gastrointestinal tracts (GI), gills, muscles, and skin. All the studied fish and mussels (n = 33) had MPs. MP fibres, fragments and sheets were detected in every GI examined, however, fibres were the only type of MPs in skins, muscles and gills and were the most abundant MP. The MPs found in the fish and mussels were mainly made of nylon (35% of the total MPs), polypropylene-low density polyethylene (30%), and polycarbonate (25%). The average numbers of MPs found in every fish specimen, expressed per wet body mass, had a moderate negative correlation with the condition factor (K) (MP/g - K: Pearson correlation r = -0.413, p = 0.049), and there was no significant relation with the growth factor (b) (r = -0.376; p = 0.068). Importantly, Luciobarbus caspius (with trophic level 2.7-2.8) bioaccumulated MPs and presented a strong correlation between their MP contamination and age (r = 0.916 p < 0.05). Greater gill mass (or related factors) played an important role in the accumulation of MPs, and there was a strong correlation between these factors for Esox lucius and Cyprinus carpio (r = 0.876; r = 0.846; p < 0.05 respectively). The highest MP/g gills (1.91 ± 2.65) were in the filter feeder Anodonta cygnea inhabiting the benthic zone. Esox lucius (piscivorous, trophic level 4.1) was the most contaminated species overall (a total of 83 MPs in 8 individuals, with 0.92 MP/g fish), and their gills where MPs mainly accumulated. Cyprinus carpio was the most contaminated specimen (MPs in specimens), while the number of MPs per mass unit increased with the trophic level. Their feeding and ecological behavior in the aquatic habitat affected the level of accumulation. This work includes evidence of translocation of MPs within the aquatic organisms.

Protein corona alleviates adverse biological effects of nanoplastics in breast cancer cells

Pollution from micro- and nanoplastics (MNPs) has long been a topic of concern due to its potential impact on human health. MNPs can circulate through human blood and, thus far, have been found in the lungs, spleen, stomach, liver, kidneys and even in the brain, placenta, and breast milk. While data are already available on the adverse biological effects of pristine MNPs (e.g. oxidative stress, inflammation, cytotoxicity, and even cancer induction), no report thus far clarified whether the same effects are modulated by the formation of a protein corona around MNPs. To this end, here we use pristine and human-plasma pre-coated polystyrene (PS) nanoparticles (NPs) and investigate them in cultured breast cancer cells both in terms of internalization and cell biochemical response to the exposure. It is found that pristine NPs tend to stick to the cell membrane and inhibit HER-2-driven signaling pathways, including phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathways, which are associated with cancer cell survival and growth. By contrast, the formation of a protein corona around the same NPs can promote their uptake by endocytic vesicles and final sequestration within lysosomes. Of note is that such intracellular fate of PS-NPs is associated with mitigation of the biochemical alterations of the phosphorylated AKT (pAKT)/AKT and phosphorylated ERK (pERK)/ERK levels. These findings provide the distribution of NPs in human breast cancer cells, may broaden our understanding of the interactions between NPs and breast cancer cells and underscore the crucial role of the protein corona in modulating the impact of MNPs on human health.

Nascently generated microplastics in freshwater stream are colonized by bacterial communities from stream and riparian sources

The purpose of this study was to examine bacterial colonization of different types of microplastics through time in a freshwater ecosystem. Microplastics are persistent pollutants in aquatic ecosystems. Bacteria readily colonize microplastic surfaces and may contribute to their degradation, but the taxa involved, and their degradative abilities, differ based on factors such as microplastic chemistry, plastic age, and specific ecosystem types. Four different common types of newly manufactured microplastics, high-density polyethylene, low-density polyethylene, polypropylene, and polystyrene, were incubated for 7 weeks in a freshwater stream and sampled. Sample collection was timed to examine the development of early and late bacterial biofilm communities. Microplastics were analyzed for changes to buoyancy, weight, contact angles (an indicator of surface roughness), bacterial community composition, and the number of bacterial cells. Time was the only significant contributing factor in the development of bacterial biofilm communities on microplastic disks over the 7-week study. Notably, the Comamonadaceae were abundant early in the study and decreased in abundance with time, while the Methylococcaceae demonstrated the opposite trend. Different physicochemical properties among the various types of microplastics had only a minor effect on bacterial community compositions of biofilms growing on the microplastics. Additionally, the surfaces of all microplastic disks became rougher over time in the stream. Collectively, our results show that microplastic surfaces undergo surface modification and community succession as time progresses, regardless of microplastic type, in a freshwater stream ecosystem.

Metagenomic analysis reveals gene taxonomic and functional diversity response to microplastics and cadmium in an agricultural soil

Both microplastics (MPs) and heavy metals are common soil pollutants and can interact to generate combined toxicity to soil ecosystems, but their impact on soil microbial communities (e.g., archaea and viruses) remains poorly studied. Here, metagenomic analysis was used to explore the response of soil microbiome in an agricultural soil exposed to MPs [i.e., polyethylene (PE), polystyrene (PS), and polylactic acid (PLA)] and/or Cd. Results showed that MPs had more profound effects on microbial community composition, diversity, and gene abundances when compared to Cd or their combination. Metagenomic analysis indicated that the gene taxonomic diversity and functional diversity of microbial communities varied with MPs type and dose. MPs affected the relative abundance of major microbial phyla and genera, while their coexistence with Cd influenced dominant fungi and viruses. Nitrogen-transforming and pathogenic genera, which were more sensitive to MPs variations, could serve as the indicative taxa for MPs contamination. High-dose PLA treatments (10%, w/w) not only elevated nitrogen metabolism and pathogenic genes, but also enriched copiotrophic microbes from the Proteobacteria phylum. Overall, MPs and Cd showed minimal interactions on soil microbial communities. This study highlights the microbial shifts due to co-occurring MPs and Cd, providing evidence for understanding their environmental risks.

Combined exposure of polystyrene microplastics and benzo[a]pyrene in rat: Study of the oxidative stress effects in the liver

Microplastics (MPs) and benzo[a]pyrene (B[a]P) are prevalent environmental pollutants. Numerous studies have extensively reported their individual adverse effects on organisms. However, the combined effects and mechanisms of exposure in mammals remain unknown. Thus, this study aims to investigate the potential effects of oral administration of 0.5μm polystyrene (PS) MPs (1 mg/mL or 5 mg/mL), B[a]P (1 mg/mL or 5 mg/mL) and combined (1 mg/mL or 5 mg/mL) on 64 male SD rats by gavage method over 6-weeks. The results demonstrate that the liver histopathological examination showed that the liver lobules in the combined (5 mg/kg) group had blurred and loose boundaries, liver cord morphological disorders, and significant steatosis. The levels of AST, ALT, TC, and TG in the combined dose groups were significantly higher than those in the other groups, the combined (5 mg/kg) group had the lowest levels of antioxidant enzymes and the highest levels of oxidants. The expression of Nrf2 was lowest and the expression of P38, NF-κB, and TNF-α was highest in the combined (5 mg/kg) group. In conclusion, these findings indicate that the combination of PSMPs and B[a]P can cause the highest levels of oxidative stress and elicit markedly enhanced toxic effects, which cause severe liver damage.

Desorption of Polycyclic Aromatic Hydrocarbons from Microplastics in Human Gastrointestinal Fluid Simulants-Implications for Exposure Assessment

Microplastics have been detected in various food types, suggesting inevitable human exposure. A major fraction may originate from aerial deposition and could be contaminated by ubiquitous pollutants such as polycyclic aromatic hydrocarbons (PAHs). While data on the sorption of pollutants to microplastics are abundant, the subsequent desorption in the gastrointestinal tract (GIT) is less understood. This prompted us to systematically investigate the release of microplastics-sorbed PAHs at realistic loadings (44-95 ng/mg) utilizing a physiology-based in vitro model comprising digestion in simulated saliva, gastric, and small and large intestinal fluids. Using benzo[a]pyrene as a representative PAH, desorption from different microplastics based on low density polyethylene (LDPE), thermoplastic polyurethanes (TPUs), and polyamides (PAs) was investigated consecutively in all four GIT fluid simulants. The cumulative relative desorption (CRD) of benzo[a]pyrene was negligible in saliva simulant but increased from gastric (4 ± 1% - 15 ± 4%) to large intestinal fluid simulant (21 ± 1% - 29 ± 6%), depending on the polymer type. CRDs were comparable for ten different microplastics in the small intestinal fluid simulant, except for a polydisperse PA-6 variant (1-10 μm), which showed an exceptionally high release (51 ± 8%). Nevertheless, the estimated contribution of microplastics-sorbed PAHs to total human PAH dietary intake was very low (≤0.1%). Our study provides a systematic data set on the desorption of PAHs from microplastics in GIT fluid simulants.

Cotransport of nanoplastics and plastic additive bisphenol AF (BPAF) in unsaturated hyporheic zone: Coupling effects of surface functionalization and protein corona

The ecological risk of combined pollution from microplastics (MPs) and associated contaminants usually depends on their interactions and environmental behavior, which was also disturbed by varying surface modifications of MPs. In this study, the significance of surface functionalization and protein-corona on the cotransport of nanoplastics (NPs; 100 nm) and the related additive bisphenol AF (BPAF) was examined in simulated unsaturated hyporheic zone (quartz sand; 250-425 μm). The electronegative bovine serum albumin (BSA) and electropositive trypsin were chosen as representative proteins, while pristine (PNPs), amino-modified (ANPs), and carboxyl-modified NPs (CNPs) were representative NPs with different charges. The presence of BPAF inhibited the mobility of PNPs/CNPs, but enhanced the release of ANPs in hyporheic zone, which was mainly related to their hydrophobicity changes and electrostatic interactions. Meanwhile, the NPs with high mobility and strong affinity to BPAF became effective carriers, promoting the cotransport of BPAF by 16.4 %-26.4 %. The formation of protein-coronas altered the mobility of NPs alone and their cotransport with BPAF, exhibiting a coupling effect with functional groups. BSA-corona promoted the transport of PNPs/CNPs, but this promoting effect was weakened by the presence of BPAF via increasing particle aggregation and hydrophobicity. Inversely, trypsin-corona aggravated the deposition of PNPs/CNPs, but competition deposition sites and increased energy barrier caused by coexisting BPAF reversed this effect, facilitating the cotransport of trypsin-PNPs/CNPs in hyporheic zone. However, BPAF and protein-coronas synergistically promoted the mobility of ANPs, owing to competition deposition sites and decreased electrostatic attraction. Although all of the NPs with two protein-coronas reduced dissolved BPAF in the effluents via providing deposition sites, the cotransport of total BPAF was improved by the NPs with high mobility (BSA-PNPs/CNPs) or high affinity to BPAF (BSA/trypsin-ANPs). However, the trypsin-PNPs/CNPs inhibited the transport of BPAF due to their weak mobility and adsorption with BPAF. The results provide new insights into the role of varying surface modifications on NPs in the vertical cotransport of NPs and associated contaminants in unsaturated hyporheic zone.

Quantitative distribution and quantized ecological threat of microplastics in farmland: Shanghai as an example

The occurrence of microplastics (MPs) in farmlands poses a threat to soil health and crop yield. There needs to be more research on the role of cropping patterns in the accumulation of MPs and quantizing the threat of MPs on soil health and crop yield. In this study, a field study was carried out to explore the role of cropping patterns in the accumulation of MPs in agricultural soil in Shanghai, China. Furthermore, the specific effect and importance of MPs and each soil physicochemical indicator to soil health and crop yield were clarified, and the threat of MPs in reducing soil health and crop yield was quantized. Relative lower MPs abundance was detected in Shanghai. MPs abundance in vegetable fields was significantly higher than that in orchards. The broad source of MPs, the acceleration of plastics breaking under artificial disturbance and warmer temperatures, and the block of MPs exchange could account for the quicker accumulation of MPs in vegetable fields. MPs have a negligible effect on microbial diversity and metabolic activity which plays a role in soil enzyme activity. Besides, MPs served as one of the critical factors for rice yield reduction.

Assessment of the occurrence and interaction between pesticides and plastic litter from vineyard plots

In this research, aged plastic fragments collected from vineyards were characterized in terms of composition, residues of pesticides, and their potential to exchange these compounds with the aquatic media. To this end, we employed the qualitative and quantitative information provided by complementary analytical techniques, including chromatography, organic and inorganic mass spectrometry, infrared spectroscopy and electronic microscopy. Debris of weathered plastics were identified as polypropylene and polyethylene, containing different types of additives, from organic UV stabilizers to inorganic fillers, such as calcium salts. Regardless of polymer type, plastic litter collected from vineyards contained residues of pesticides, and particularly of fungicides, with total concentrations in the range of values from 114 ng g-1 to 76.4 μg g-1. Data obtained under different extraction conditions suggested that a fraction of these compounds was absorbed in aged polymers, penetrating inside the material. The parallel analysis of plastic litter and vineyard soils reflected higher pesticide residues in the former matrix. Furthermore, several fungicides, considered as labile in vineyard soils (i.e. zoxamide and folpet), were those showing the highest levels in plastic litter. Simulated sorption-desorption studies, with plastic debris in contact with surface water, demonstrated the higher affinity of aged materials by moderately polar pesticides than their new counterparts. For the first time, the manuscript highlights the presence of plastic litter in vineyards soils, reflecting the accumulation of several fungicides in this matrix, in some cases, with a different stability pattern to that observed in the soil from same vineyards.

A global review on the abundance and threats of microplastics in soils to terrestrial ecosystem and human health

Soil is the source and sink of microplastics (MPs), which is more polluted than water and air. In this paper, the pollution levels of MPs in the agriculture, roadside, urban and landfill soils were reviewed, and the influence of MPs on soil ecosystem, including soil properties, microorganisms, animals and plants, was discussed. According to the results of in vivo and in vitro experiments, the possible risks of MPs to soil ecosystem and human health were predicted. Finally, in light of the current status of MPs research, several prospects are provided for future research directions to better evaluate the ecological risk and human health risk of MPs. MPs concentrations in global agricultural soils, roadside soils, urban soils and landfill soils had a great variance in different studies and locations. The participation of MPs has an impact on all aspects of terrestrial ecosystems. For soil properties, pH value, bulk density, pore space and evapotranspiration can be changed by MPs. For microorganisms, MPs can alter the diversity and abundance of microbiome, and different MPs have different effects on bacteria and fungi differently. For plants, MPs may interfere with their biochemical and physiological conditions and produce a wide range of toxic effects, such as inhibiting plant growth, delaying or reducing seed germination, reducing biological and fruit yield, and interfering with photosynthesis. For soil animals, MPs can affect their mobility, growth rate and reproductive capacity. At present epidemiological evidences regarding MPs exposure and negative human health effects are unavailable, but in vitro and in vivo data suggest that they pose various threats to human health, including respiratory system, digestive system, urinary system, endocrine system, nervous system, and circulation system. In conclusion, the existence and danger of MPs cannot be ignored and requires a global effort.

Microplastics exposure: implications for human fertility, pregnancy and child health

Plastics found in our everyday environment are becoming an increasing concern for individual and population-level health, and the extent of exposure and potential toxic effects of these contaminants on numerous human organ systems are becoming clear. Microplastics (MPs), tiny plastic particles, appear to have many of the same biological effects as their plastic precursors and have the compounded effect of potential accumulation in different organs. Recently, microplastic accumulation was observed in the human placenta, raising important questions related to the biological effects of these contaminants on the health of pregnancies and offspring. These concerns are particularly heightened considering the developmental origins of health and disease (DOHaD) framework, which postulates that in utero exposure can programme the lifelong health of the offspring. The current review examines the state of knowledge on this topic and highlights important avenues for future investigation.

Microplastics are ubiquitous and increasing in soil of a sprawling urban area, Phoenix (Arizona)

Microplastics are environmental contaminants that have been extensively studied in marine and aquatic environments; terrestrial ecosystems, where most microplastics originate and have the potential to accumulate, typically receive less attention. This study aims to investigate the spatial and temporal soil concentrations of microplastics in a large desert metropolitan area, the Central Arizona-Phoenix Long-Term Ecological Research (CAP-LTER) area. Soil samples from the Ecological Survey of Central Arizona (ESCA) surveys (2005 and 2015) were leveraged to study spatial distributions and the temporal change of microplastic abundances. The temporal soil microplastics data were supplemented by microplastics deposition fluxes in a central location within the area (Tempe, AZ) for a period of one year (Oct 5th, 2020 to Sept 22nd, 2021). Samples were processed and microplastics were counted under an optical microscope to obtain quantitative information of their distribution in soil. Results for the spatial variation of the microplastic abundances in soil samples in Phoenix and the surrounding areas of the Sonoran Desert from 2015 depict microplastics as ubiquitous and abundant in soils (122 to 1299 microplastics/kg) with no clear trends between different locations. Microplastics deposition fluxes show substantial deposition in the local area (71 to 389 microplastics/m2/day with an average deposition flux of 178 microplastics/m2/day) but the role of resuspension and redistribution by dust storms to deposition may contribute to the unclear spatial trends. Comparison between the 2005 and 2015 surveys show a systematic increase in the abundance of microplastics and a decrease in microplastics size. Micro-Raman spectroscopy identified a variety of plastics including PE, PS, PVC, PA, PES and PP. However, a majority of microplastics remained chemically unidentifiable. Polyethylene was present in 75 % of the sampling sites and was the most abundant polymer on average in all soil samples.

Airborne microplastics: A narrative review of potential effects on the human respiratory system

There has been growing evidence showing the widespread of airborne microplastics (AMPs) in many regions of the world, raising concerns about their impact on human health. This review aimed to consolidate recent literature on AMPs regarding their physical and chemical characteristics, deposition in the human respiratory tract, translocation, occurrence from human studies, and toxic effects determined in vitro and in vivo. The physical characteristics influence interactions with cell membranes, cellular internalization, accumulation, and cytotoxicity resulting from cell membrane damage and oxidative stress. In addition, prolonged exposure to AMP-associated toxic chemicals might lead to significant health effects. Most toxicological assessments of AMPs in vitro and in vivo have demonstrated that oxidative stress and inflammation are major mechanisms of action for their toxic effects. Elevated reactive oxygen species production could lead to mitochondrial dysfunction, inflammatory responses, and subsequent apoptosis in experimental models. To date, there has been some evidence suggesting exposure in humans. However, the data are still insufficient, and adverse human health effects need to be investigated. Future research on the existence, exposure, and health effects of AMPs is required for developing preventive and mitigation measures to protect human health.

Human health risk model for microplastic exposure in the Arctic region

Microplastics enriched with carcinogens like heavy metals, polycyclic aromatic hydrocarbons (PAHs), and their derivatives are ubiquitous in Arctic waters. They contaminate the local land and sea-based food sources, which is a significant health hazard. It is thus imperative to assess the risk posed by them to the nearby communities, which primarily rely on locally available food sources to meet their energy requirements. This paper proposes a novel ecotoxicity model to assess the human health risk posed by microplastics. The region's geophysical and environmental conditions affecting human microplastic intake, along with the human physiological parameters influencing biotransformation, are incorporated into the developed causation model. It investigates the carcinogenic risk associated with microplastic intake in humans via ingestion in terms of incremental excess lifetime cancer risk (IELCR). The model first evaluates microplastic intake and then uses reactive metabolites produced due to the interaction of microplastics with xenobiotic metabolizing enzymes to assess cellular mutations that result in cancer. All these conditions are mapped in an Object-Oriented Bayesian Network (OOBN) framework to evaluate IELCR. The study will provide a vital tool for formulating better risk management strategies and policies in the Arctic region, especially concerning Arctic Indigenous peoples.

Magnetic loofah sponge biochar facilitates microbial interspecies cooperation in surface and subsurface sediments for enhanced PAH biodegradation

Magnetic biochar had been used for the bioremediation of polycyclic aromatic hydrocarbon (PAH)-contaminated sediments. However, the long-term remediation pattern of vertical stratification driven by the application of magnetic biochar and the assembly of microbes had received little attention. In this study, magnetic loofah sponge biochar (MagLsBC), magnetic iron oxide (MagOx) and magnetic coconut shell activated carbon (MagCoAC) were applied for the 900-day remediation of contaminated sediments. Significant (p < 0.05) PAH biodegradation was observed in both the surface and subsurface sediments with MagLsBC addition. However, enhanced PAH biodegradation was observed only in the surface sediments with MagOx and MagCoAC treatments. Magnetotactic bacteria (Magnetococcus) was dominant genera in surface sediments and indigenous PAH degradation bacteria were more abundant in subsurface sediments of MagLsBC relative to other bacterial communities. The network interaction between microbes in surface and subsurface sediments with MagLsBC treatments was a less complex and tighter than those with MagCoAC, MagOx or Control treatments. Long-distance electron transfer rates could be enhanced through cooperation between magnetotactic bacteria and indigenous degradation bacteria, thus accelerating PAH degradation in sediment with MagLsBC treatment, especially in the underlying sediment.

Microplastics in coastal blue carbon ecosystems: A global Meta-analysis of its distribution, driving mechanisms, and potential risks

Microplastics, as emerging pollutants, have become a global environmental concern. Blue carbon ecosystems (BCEs) are threatened by microplastics. Although substantial studies have explored the dynamics and threats of microplastics in BCEs, the fate and driving factors of microplastics in BCEs on a global scale remain largely unknown. Here, the occurrence, driving factors, and risks of microplastics in global BCEs were investigated by synthesizing a global meta-analysis. The results showed that the abundance of microplastics in BCEs has notable spatial differences worldwide, with the highest microplastic concentrations in Asia, especially in South and Southeast Asia. Microplastic abundance is influenced by the vegetation habitat, climate, coastal environment, and river runoff. The interaction of geographic location, ecosystem type, coastal environment, and climate enhanced the effects of microplastic distribution. In addition, we found that microplastic accumulation in organisms varied according to feeding habits and body weight. Significant accumulation was observed in large fish; however, growth dilution effects were also observed. The effect of microplastics on the organic carbon content of sediments from BCEs varies by ecosystem; microplastic concentrations do not necessarily increase organic carbon sequestration. Global BCEs are at a high risk of microplastic pollution, with high microplastic abundance and toxicity driving the high pollution risk. Finally, this review provides scientific evidence that will form the basis for future microplastic research, focusing on the transport of microplastics in BCEs; effects on the growth, development, and primary productivity of blue carbon plants; and soil biogeochemical cycles.

Sources, distribution, and environmental effects of microplastics: a systematic review

Microplastics (MPs) are receiving increasing attention from researchers. They are environmental pollutants that do not degrade easily, are retained for prolonged periods in environmental media such as water and sediments, and are known to accumulate in aquatic organisms. The aim of this review is to show and discuss the transport and effects of microplastics in the environment. We systematically and critically review 91 articles in the field of sources, distribution, and environmental behavior of microplastics. We conclude that the spread of plastic pollution is related to a myriad of processes and that both primary and secondary MPs are prevalent in the environment. Rivers have been indicated as major pathways for the transport of MPs from terrestrial areas into the ocean, and atmospheric circulation may be an important avenue for transporting MPs between environmental compartments. Additionally, the vector effect of MPs can change the original environmental behavior of other pollutants, leading to severe compound toxicity. Further in-depth studies on the distribution and chemical and biological interactions of MPs are highly suggested to improve our understanding of how MPs behave in the environment.

Chemicals/materials of emerging concern in farmlands: sources, crop uptake and potential human health risks

Certain chemicals/materials that are contaminants of emerging concern (CECs) have been widely detected in water bodies and terrestrial systems worldwide while other CECs occur at undetectable concentrations. The primary sources of CECs in farmlands are agricultural inputs, such as wastewater, biosolids, sewage sludge, and agricultural mulching films. The percent increase in cropland area during 1950-2016 was 30 and the rise in land use for food crops during 1960-2018 was 100-500%, implying that there could be a significant CEC burden in farmlands in the future. In fact, the alarming concentrations (μg kg^-1) of certain CECs such as PBDEs, PAEs, and PFOS that occur in farmlands are 383, 35 400 and 483, respectively. Also, metal nanoparticles are reported even at the mg kg^-1 level. Chronic root accumulation followed by translocation of CECs into plants results in their detectable concentrations in the final plant produce. Thus, there is a continuous flow of CECs from farmlands to agricultural produce, causing a serious threat to the terrestrial food chain. Consequently, CECs find their way to the human body directly through CEC-laden plant produce or indirectly via the meat of grazing animals. Thus, human health could be at the most critical risk since several CECs have been shown to cause cancers, disruption of endocrine and cognitive systems, maternal-foetal transfer, neurotoxicity, and genotoxicity. Overall, this comprehensive review provides updated information on contamination of chemicals/materials of concern in farmlands globally, sources for their entry, uptake by crop plants, and their likely impact on the terrestrial food chain and human health.

Preliminary Study on the Distribution, Source, and Ecological Risk of Typical Microplastics in Karst Groundwater in Guizhou Province, China

Karst groundwater is one of the important drinking water sources in karst areas, and it has an important role in maintaining the regional ecosystem and human health. The study of microplastics (MPs) in karst groundwater has rarely been reported, and the occurrence and migration behavior of MPs under the unique environmental conditions of karst is unclear. This study selected cave groundwater and common MPs in karst areas to explore the occurrence characteristics of MPs in groundwater to clarify the factors affecting the distribution and migration of MPs. The results showed that the abundance of MPs in karst groundwater was between 2.33 and 9.50 items·L-1, with an average abundance of 4.50 items·L-1. The microplastic size, type, color, and chemical composition were primarily 1~5 mm, film and fiber, color and transparent, and PS and PE, respectively. The risk characterization ratio (RCR) index results indicated that 80% of the samples were at a low ecological risk level, whereas 60% of the sampling points after concentrated rainfall in June were a medium ecological risk. The study showed that rainfall events significantly changed the abundance and migration of MPs in karst groundwater. The Pearson analysis showed a positive correlation between microplastic distribution and suspended particles (SP), total organic carbon (TOC), and water velocity (WV) in water. The study indicated that strong soil erosion in karst areas may also be one of the main sources of MPs in karst groundwater, and that karst groundwater microplastic pollution is an environmental problem that should not be ignored.