Microplastics In Samples Research Articles

What Goes Around Should Not Move Around: Immobilizing Microplastics as a New Approach for Analytical Ring Trials.

Microplastics have gained importance as pervasive environmental particulate pollutants. Their analysis demands precise quantification methods, with interlaboratory comparisons (ILCs) being crucial for performance assessment. Typically, ILCs follow a parallel design: participants each analyze their own sample specimen, often with significant variability due to challenges in producing identical subsamples of the particulate analyte, inseparably masking the relevant uncertainty sources the ILC intends to measure. We provide a filtration-immobilization approach for particles ≤100 μm, creating permanently immobilized microplastics samples. This enables serial ILC designs where participants sequentially measure the same sample. Demonstrating the concept using 5 polymers immobilized on 10 μm pore-sized silicon filters, we expose the specific measurement uncertainty being 77% lower than the total combined uncertainty observed in a parallel ILC (relative standard deviations: 5 and 23%, respectively). Particle immobilization opens further applications in sample archiving and creation of durable reference samples also for other fields of particulate matter research beyond microplastics.

Does Microplastic Pollution in the Epikarst Environment Coincide with Rainfall Flushes and Copepod Population Dynamics?

Karst areas are characteristic landscapes formed by the dissolution of soluble rocks, whose hydrology is largely influenced by rapid infiltration through the karst massif. These areas are often hotspots of biodiversity, especially for epikarst and cave fauna. The epikarst, the uppermost layer of the unsaturated zone, plays a crucial role in regulating water flow in karst aquifers. The aim of this study was to investigate the extent of microplastic (MP) pollution, its relationship with precipitation and its correlation with copepod populations in karst areas. The study was conducted between April 2021 and October 2022 in the Postojna–Planina karst area in SW Slovenia at surface and underground sampling sites to determine the pathways of MP pollution from the surface to the depth of the karst massif. The results indicate that heavier rainfall flushes out more MP contaminants from the surface and epikarst environment. The transport dynamics of MP pollution are similar to the dynamics of copepods, which are the baseline organisms for the food chain in caves. One MP sample contained only polyamide particles, which could indicate clothing as a possible source of pollution, but the results are inconclusive. With this study, we provide the first insight into the transport of MP pollution from the surface environment to deeper karst massifs.

Microplastic fate in Arctic coastal waters: accumulation hotspots and role of rivers in Svalbard

Little is known about the role of remote and sparsely populated Arctic coastal zones in the microplastic cycle. Distribution of microplastics was studied in the Svalbard fjords in June – July 2022 with the main goal of assessing rivers’ role in the fate of microplastic in Arctic coastal waters. Surface microplastics (0 – 20 cm depth, 500 – 5000 µm size) were sampled with a neuston net in triplicate per study site in parallel with sampling of subsurface microplastics with a pump system (1.5 m depth, 100 – 5000 µm size). The central part of Isfjorden and its several branches covering populated and unpopulated fjords were studied; the sampling was conducted during an intense riverine discharge in all studied sites. Maximum abundance of surface microplastics (71,400 items/km2 or 0.19 iterms/m3, 0.19 mg/m3) was found along the river plume border in the middle of populated Adventfjorden indicating importance of both local sources and surface hydrodynamics in the formation of microplastics accumulation hotspots. All other unpopulated fjords were free of the floating on the sea surface microplastics as river discharge prevented transport of microplastics inside the fjords. The highest concentration of subsurface microplastics was found in the central part of Isfjorden and the lowest – in river plume waters, which also indicates the removal of microplastics from the inner part of fjords during an intensive river discharge. Our results may suggest that Arctic rivers flowing through unpopulated areas bring clean water and thereby reduce level of microplastic pollution in the coastal waters. In contrast to the rest of the world’s ocean, rivers are not the main source of microplastic pollution in the Arctic Ocean.

Expanding sample volume for microscopical detection of nanoplastics

The extent of nanoplastic pollution has raised severe environmental and health concerns. While the means for microplastic detection are abundant, improved tools for nanoplastic detection are called-for. State-of-the-art microscopic techniques can detect nanoplastics down to tens of nanometers, however, only from small sample sizes (typically ∼10μl). In this work, we describe a method that enables sampling of 1 l of seawater by the means of correlative Raman- and SEM-techniques. This is achieved by adapting common microplastic sample purification protocols to suit the nanoplastic study. In addition, we decorate a membrane filter with SERS-property to amplify the Raman signals. Together, the purification method combined with the use of the SERS-activated-membrane-filter enables identification and imaging of individual nanoplastic particles from significantly larger sample sizes than before. In the nanoscale the average recovery rate is 5 %. These results aim to provide useful tools for researchers in the fight against plastic pollution.

Airborne microplastic monitoring: Developing a simplified outdoor sampling approach using pollen monitoring equipment

A novel, yet simple, airborne microplastic (MP) sampling approach using global pollen monitoring equipment was applied to identify, characterise and quantify outdoor airborne MPs for the first time. Modification of Burkard spore trap tape adhesive provided particle capture and facilitated downstream spectroscopy analysis. 36 polymer types were identified from a total of 21 days sampling using Burkard spore traps at two locations (United Kingdom and South Africa). MPs were detected in 95 % of daily samples. Mean MP particle levels were 2.0 ± 0.9 MP m-3 (11 polymer types) in Hull (U.K.), during March, 2.9 ± 2.0 MP m-3 (16 types) in Hull in July, and 11.0 ± 5.7 MP m-3 (29 types) in Gqeberha, (S.A.) in August 2023. The most abundant polymer type was nylon (Gqeberha). The approach was compared with two passive sampling methods whereby 27 polymer types were identified and of these, 6 types were above the limit of quantification (LOQ), with poly(methacrolein:styrene) (PMA/PS) the most abundant. Irregularly shaped MPs < 100 µm in length were predominant from all sampling approaches. For the first time, airborne MPs were chemically characterised and quantified using volumetric pollen sampling equipment, representing a viable approach for future airborne MP monitoring.

Microbial Consortia in the Remediation of Single-Use Waste: The Case of Face Masks

This study presents the results of evaluating hydrocarbonoclastic consortia in the biodegradation of microplastics derived from single-use, triple-layered polypropylene face masks. The choice of this carbon source was driven by the need to address the increase in single-use waste generated during the recent SARS-CoV-2 pandemic, as the use of face masks was a mandatory protective measure. Two bubble column bioreactors were used, each containing hydrocarbonoclastic consortia sourced from the Port of Veracruz and the Gulf of Mexico. The biodegradation activity of these consortia was assessed by observing the physical appearance of microplastic samples under a stereoscope and a microscope, as well as by calculating the weight loss of polypropylene after 15 days. The results revealed that the consortium from the Gulf of Mexico, with a maturity of 1 year, showed a higher capacity for polypropylene biodegradation, achieving a 19.98% degradation rate. This consortium also demonstrated more stable kinetics during the experimentation period. In contrast, the younger consortium from the Port of Veracruz exhibited a lower biodegradation rate of 3.77% and variable growth kinetics. Hydrocarbonoclastic bacteria identified within the consortia included Pseudomonas aeruginosa, Enterococcus faecalis, and Vibrio parahaemolyticus, among others. The hydrocarbonoclastic consortia have the potential to biodegrade from various forms of plastic waste, including single-use face masks.

Monitoring of contamination by microplastics on sandy beaches at Vulcano Island (Sicily, Italy) by hyperspectral imaging.

In this work, the monitoring and characterization of large microplastics (1-5mm) collected from sandy beaches of Vulcano Island (Aeolian Islands, Sicily, Italy) were carried out for the first time. Microplastics were sampled from two beaches, "Gelso" and "Sabbie Nere," in three different time periods. The following characteristics of microplastic samples were assessed: quantity, distribution, categories, color, polymer type, size, and shape parameters. The polymers were identified using hyperspectral imaging, whereas an automatic image analysis approach was employed to determine microplastics' morphological and morphometrical attributes. Finally, the microplastic diversity integrated index was computed to obtain information on the potential emission sources of microplastics. It was found that the concentration of microplastics varies from 0.27 particles/kg_dw to 1.35 particles/kg_dw with fragment being the main collected category, with minor amount of pellet, foam, film, and filament. The predominant color of microplastics was by far white, followed by blue and yellow. The identified polymers were polyethylene and polypropylene followed by expanded polystyrene, polyamide, polystyrene, and polyethylene terephthalate. The morphological and morphometrical characterization highlighted a large variability for most size and shape parameters. Finally, the Microplastics Diversity Integrated Index results showed average indices compared to the literature, with higher values for the "Gelso" site (0.656), indicating a higher heterogeneity of sources, with respect to "Sabbie Nere" beach (0.530).

Microplastics in surface seawater of Kongsfjorden, Svalbard, Arctic

Microplastics have now become an emerging contaminant with high concern in the Arctic and Sub-Arctic Region. Here, the Kongsfjorden system in the Arctic has been investigated for abundance, distribution, and characteristic of microplastics in surface seawater. Eighteen samples were collected using an in-situ filtration sampling method, and then analyzed by Fourier-transform infrared spectroscopy. The average abundance of microplastics in surface seawater was 3.6 items m−3, with an abundance range of 0.0—10.0 items m−3. The highest abundance of microplastics was located adjacent to the eddy in Kongsfjorden, where a microplastic accumulation zone might have formed. Microplastics transported by ocean currents and those from local discharges might converge in this zone. Two sampling stations were set up at the wastewater treatment plant outfall, which showed an abundance range of 4.0—6.0 items m−3, slightly higher than the average abundance. Of the six polymer types identified, rayon, polyester and polyamide were the most common composition. Proportions in fiber form in surface water was 84.6 %, and blue (28.2 %) and transparent (25.6 %) were predominant colors. Most microplastics (>90.0 %) were less than 1 mm in the longest dimension. This study provided important baseline data as well as a practical microplastic sampling method for polar marine environments.

Spatiotemporal variations and the ecological risks of microplastics in the watersheds of China: Implying the impacts of the COVID-19 pandemic

China is not only the first reported place of the COVID-19 pandemic but also is the biggest microplastic emitter in the world. Nevertheless, the impact of the COVID-19 pandemic on microplastic pollution in the watersheds of China remains poorly understood. To address this, the present study conducted a data mining and multivariate statistical analysis based on 8898 microplastic samples from 23 Chinese watershed systems before and during the COVID-19 pandemic. The results showed that the COVID-19 pandemic extensively affected the abundance, colors, shapes, polymer types, and particle sizes of microplastic in Chinese watershed systems. Before and during the COVID-19 pandemic, 77.27 % of the Chinese watershed systems observed increased microplastic abundance. Moreover, the COVID-19 pandemic itself, natural conditions (such as altitude and weather), and anthropogenic factors (such as civil aviation throughput) are highly intertwined, jointly impacting the microplastic in the watersheds of China. From the perspective of ecological risks, the COVID-19 pandemic was more likely to aggravate the microplastic pollution in the middle and down reaches of the Yangtze River Watersheds. Overall, whether before or during the COVID-19 pandemic, the main watershed systems of China still stayed at a high pollution level, which rang the alarm bell that watershed systems of China had been at serious ecological risk accused of microplastic contamination.

Microplastic Particles Contain Ice Nucleation Sites That Can Be Inhibited by Atmospheric Aging.

Recent research has shown that microplastics are widespread in the atmosphere. However, we know little about their ability to nucleate ice and their impact on ice formation in clouds. Ice nucleation by microplastics could also limit their long-range transport and global distribution. The present study explores the heterogeneous ice-nucleating ability of seven microplastic samples in immersion freezing mode. Two polypropylene samples and one polyethylene terephthalate sample froze heterogeneously with median freezing temperatures of -20.9, -23.2, and -21.9 °C, respectively. The number of ice nucleation sites per surface area, ns(T), ranged from 10-1 to 104 cm-2 in a temperature interval of -15 to -25 °C, which is comparable to that of volcanic ash and fungal spores. After exposure to ozone or a combination of UV light and ozone, simulating atmospheric aging, the ice nucleation activity decreased in some cases and remained unchanged in others. Our freezing data suggest that microplastics may promote ice formation in cloud droplets. In addition, based on a comparison of our freezing results and previous simulations using a global transport model, ice nucleation by microplastics will impact their long-range transport to faraway locations and global distribution.

Insights into the seasonal distribution of microplastics and their associated biofilms in the water column of two tropical estuaries

The present study describes the seasonal distribution of microplastics (MPs) and their associated biofilms in the water column of the Netravathi-Gurupura estuary, southwest India. An average abundance of 8.15 (±3.81) particles/l and 1.14 (±0.78) particles/l was observed during the wet and dry seasons, respectively. Fibres, films, and fragments accounted for majority of the microplastics. Polyethylene terephthalate, polyethylene, polyurethane, polyester, polystyrene, and high-density polyethylene were the major polymers. The risk assessment revealed a low Pollution Load Index, but the Polymer Hazard Index showed higher toxicity. Diatoms from nine genera were observed attached to the microplastic samples with Amphora and Navicula spp. reported in both estuaries during both seasons. The considerable diversity of diatoms, along with other microbial groups, in microplastic-associated biofilms in this study, highlights the urgent need to understand the structure and development of microplastic-associated biofilms and their role in the vertical and horizontal transport of microplastics in tropical estuaries.

Characteristics, sources and potential ecological risk of atmospheric microplastics in Lhasa city

Atmospheric microplastics are important contributors to environmental contamination in aquatic and terrestrial systems and pose potential ecological risks. However, studies on atmospheric microplastics are still limited in urban regions of the Tibetan Plateau, a sentinel region for climate and environmental change under a warming climate. In this study, the occurrence and potential ecological risk of atmospheric microplastics were investigated in samples of suspended atmospheric microplastics collected in Lhasa city during the Tibetan New Year in February 2023. The results show that the average abundance of atmospheric microplastics in Lhasa was 7.15 ± 2.46 MPs m−3. The sizes of the detected microplastics ranged from 20.34 to 297.18 μm, approximately 87% of which were smaller than 100 μm. Fragmented microplastics (95.76%) were the dominant shape, followed by fibres (3.75%) and pellets (0.49%). The primary polymer chemical components identified were polyamide (68.73%) and polystyrene (16.61%). The analysis of meteorological data and the backwards trajectory model indicated the air mass in Lhasa mainly controlled by westwards, and the atmospheric microplastics mainly originated from long-distance atmospheric transport. The potential ecological risk index assessment revealed that the atmospheric microplastic pollution in Lhasa was relatively low. This study provides valuable insights and a scientific foundation for future research on the prevention and control of atmospheric microplastic pollution in Lhasa and other ecologically sensitive cities.

Microplastic Distribution Characteristics Considering the Marine Environment Based on Surface Seawater Quality Parameters in Southern Sea of Korea, 2019

The present study determined the microplastic distributions in the surface water of the Southern Sea of Korea (SS01–SS09) in September 2019, depending on three groups (Groups A, B, and C) categorized via the principal component analysis and cluster analysis using the water quality parameters (water temperature, salinity, pH, dissolved oxygen, suspended particulate matter, and chlorophyll-a). The microplastic samples in the surface water were collected using a 300 μm-mesh neuston net. The microplastic abundance ranged from 0.10 to 5.08 (average 0.71 ± 1.64) particles/m3 in the entire sampling area. Median values in Groups A (SS01, SS02, and SS07), B (SS05, SS08, and SS09), and C (SS03, SS04, and SS06) were 0.14 ± 0.02, 0.12 ± 0.14, and 0.17 ± 2.85 particles/m3, respectively, and there were no statistically significant differences (p &lt; 0.050). However, it was highlighted that the most considerably numerous microplastic abundance in SS04 (5.08 particles/m3) revealed relatively high water temperatures distinguished from other sampling areas. Polystyrene, consisting mainly of expanded polystyrene, was the predominant polymer type, accounting for 81.5% in Groups A, 84.4% in B, and 97.0% in C. The particle size in Group C (average 3.11 ± 1.08 mm) was statistically larger (p &lt; 0.001) than those of Groups A (average 0.71 ± 1.06 mm) and B (average 0.98 ± 1.22 mm). Only fragment and sheet shapes were found in all the sampling points and the former, which consisted of the secondary microplastics regardless of the groups, was the dominant type. The fragment composition gradually increased from 77.3% in Group A, 96.7% in B, to 99.1% in C. However, the strategy studies should be investigated in the foreseeable future to supplement the current study limitations, such as verifying the effect of the Yangtze River and the Tsushima warm current, and seasonal fluctuation.

Influence of agricultural activity in corn farming on airborne microplastic in surrounding elementary school

Microplastics (MPs) have been widely detected in agricultural soils, and agricultural activities have been identified as an important factor influencing the abundance of MPs in the air. However, no studies have investigated whether agricultural activities are contributors to airborne MPs in buildings near farms. We collected airborne MP samples using an active sampling method from an elementary school near corn farms during different cultivation stages to assess the impact of agricultural activities on MPs in the study school near farms. Our data showed that the predominant shapes, sizes, colors, and polymer compositions were fragments, 2–50 μm, black or grey, and polyethylene terephthalate, respectively, during all cultivation stages. The highest and lowest MP concentrations were recorded during the land preparation (56.8 ± 7.4 particles/m3, August 2022) and growth (2.5 ± 1.8 particles/m3, February 2022) stages, respectively. A multiple-path particle dosimetry model revealed that the deposition fractions of MPs in humans were highest in the head; the highest and lowest deposition rates and fluxes of MPs in the airway were found during the land preparation and growth stages, respectively. The concentration of MPs did not present a positive correlation with potassium or crustal elemental concentration; however, it did show a positive association with temperature value. Therefore, our data did not show that corn cultivation influences MP concentrations in the study school near corn farms; instead, temperature was an important influencing factor.

Assessment of microplastics pollution level on clam farming and bathing beaches: a case study of Thanh Phu in Ben Tre, Vietnam

ABSTRACT This study focused on the investigation microplastics (MPs) with a size of ≤1.0 mm in sand samples from Thanh Phu beach, Ben Tre, Vietnam. MPs in sand from the clam beach (from 39.67 ± 6.67 to 92.00 ± 12.93 items kg−1 dried sand) were higher than those from the bathing beach (from 21.33 ± 8.76 to 51.67 ± 16.11 items kg−1 dried sand), indicating a direct contribution of MPs from coastal aquaculture. For the clam beach, MPs in surface samples (0–4 cm) were lower than in deep samples (4–6 cm). In contrast, MPs in surface samples (0–2 cm) from the bathing beach were higher than deep samples (2–5 cm). A combination of microscopy and Fourier-transform infrared spectroscopy methods confirmed that 62.5% of the representative MPs samples or 18.9% of the suspected MPs samples were plastics. Low-density polyethylene, polypropylene and polyethylene terephthalate were the largest in abundance. Further studies are needed to assess the environmental risk of MPs accumulation.

Sampling and Analysis of Microplastics in the Coastal Environments of Sri Lanka: Estuaries of the Kelani River to Mahaoya

Microplastic pollution (MP) in marine environments around the globe is severe and insufficient precautions have yet to be taken for its prevention. The focus of this study was on quantifying MPs from beach sediment and seawater samples and identifying their distributions and types along the western coast of Sri Lanka from the Kelani River estuary to the Mahaoya estuary. Nine sites along this 42 km stretch were selected, and random sampling was employed to collect a minimum of eight sediment samples from each site between October and December 2021. Water samples were also collected, parallel to the sediments, from the ocean surface. FTIR analysis revealed that most of the MPs found were polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), and phenol formaldehyde resin. The mean abundance of MPs varied from 2.0 ± 0.6 items/L to 161.0 ± 15.7 items/L in water samples and from 3.0 ± 0.3 items/m2 to 656.0 ± 34.5 items/m2 in sediment samples. The MPs found were identified in different shapes as fragments (80.2%), pellets (14.9%), fibers (2.7%), and foams (2.5%). Analysis revealed that the beach sediments were contaminated with PS, phenol formaldehyde resin, PET, PP, and PE, while the surface seawater was dominated by phenol formaldehyde resin, PS, PP, and PE.

Combined environmental pressure induces unique assembly patterns of micro-plastisphere biofilm microbial communities in constructed wetlands

The characteristics and dynamics of micro-plastisphere biofilm on the surface of microplastics (MPs) within artificial ecosystems, such as constructed wetlands (CWs), remain unclear, despite these ecosystems’ potential to serve as sinks for MPs. This study investigates the dynamic evolution of micro-plastisphere biofilm in CWs, utilizing simulated wastewater containing sulfamethoxazole and humic acid, through physicochemical characterization and metagenomic analysis. Two different types of commercial plastics, including non-degradable polyethylene and degradable polylactic acid, were shredded into MPs and studied. The findings reveal that the types, shape and incubation time of MPs, along with humic acid content in wastewater, affected the quantity and quality of biofilms, such as the biofilm composition, spatial structure and microbial communities. After just 15 days into incubation, numerous microbials were observed on MP samples, with increases in biofilms content and enhanced humification of extracellular polymeric substances over time. Additionally, microbial communities on polylactic acid MPs, or those incubated for longer time, exhibit higher diversity, connectivity and stability, along with reduced vulnerability. Conversely, biofilms on polyethylene MPs were thicker, with higher potential for greenhouse gas emission and increased risk of antibiotic resistance genes. The addition of humic acid demonstrated opposite effects on biofilms across environmental interfaces, possibly due to its dual potential to produce light-induced free radicals and serve as a carbon source. Binning analysis further uncovered a unique assembly pattern of nutrients cycle genes and antibiotic resistance genes, significantly correlated within micro-plastisphere microbial communities, under the combined stress of nutrition and sulfamethoxazole. These results emphasize the shaping of micro-plastisphere biofilm characteristics by unique environmental conditions in artificial ecosystems, and the need to understand how DOM and other pollutants covary with MP pollution.

Fluorescent labelling combined with confocal differential Raman spectroscopy to detect microplastics in seawater

As an emerging marine pollutant, microplastics represent a focal point in global monitoring and management efforts. With seawater accounts for 97 % of the total global water resources, scientific assessments of microplastics in seawater are crucial for pollution control and management of marine environments. This study focuses on investigating microplastics in near-shore seawater and proposes a rapid and accurate detection method using a constructed confocal Raman spectroscopy detection system. By optimizing the pretreatment process of seawater microplastic samples, the efficient removal of organic matter interference in microplastic detection is achieved. Employing fluorescent labeling addresses the issues of prolonged detection time and high false positive rates associated with traditional methods, enabling rapid differentiation between microplastics and other substances and significantly enhancing detection efficiency and accuracy. Additionally, the use of differential Raman spectroscopy effectively mitigates fluorescence signal interference, thus improving the signal-to-noise ratio of the spectra. By employing dual-wavelength laser excitation at 784 nm/785 nm, microplastics such as polyethylene (PE), polypropylene (PP), polystyrene (PS) ranging in size from 60 to 500 μm are successfully detected in seawater. The results demonstrate that the proposed pretreatment method for seawater microplastics and novel detection techniques enable rapid screening and comprehensive non-destructive detection of microplastics in seawater, thereby facilitating the characterization of marine microplastics and providing scientific support for enhancing the management of microplastic pollution and ecological risk control.

Microplastic Contamination of the Seawater in the Hamsilos Bay of the Southern Black Sea

The marine ecosystem is severely threatened by microplastics. The entire marine environment of the Black Sea is contaminated with both macro- and microplastics but the contamination of the water column with this pollutant has received less attention. This study aims to obtain data on the microplastic abundance, and vertical and temporal distribution of the microplastics in the water column of Hamsilos Bay which is a natural protected area, and an important area for fishery and tourism on the Sinop coast in the Black Sea. This study was carried out for 12 months in 7 stations. Microplastic abundance varied among 5.58 ± 6.12–8.12 ± 9.17 pieces/m3 in and 1.74 ± 0.80–21.07 ± 3.84 pieces/m3 in stations. The dominant microplastics were fibre by shape (73.92%), 1–2 mm (28.35%) by size class, and blue (37.98%) by colour. The synthetic polymers in the examined microplastic samples of this study were PET (47%), PE (34%), HDPE (10%), PVC (7%) and PS (2%). The results of this study show that the coastal area is widely contaminated with microplastics. Microplastic pollution is an increasingly significant environmental issue that poses a threat to the Black Sea which is particularly vulnerable to microplastic pollution. The region is an important ecological hotspot in the Black Sea and this study can provide valuable insights into the extent of microplastic pollution and will contribute to the literature on the evaluation of microplastic pollution in marine ecosystems. These types of investigations; efforts to address the environmental challenges facing the Black Sea, including the development of programs to reduce pollution, increase sustainability, and support the protection of the region's natural resources, are crucial to its continuity.

Enhancement of microplastics degradation with MIL-101 modified BiOI photocatalyst under light and dark alternated system

The composite material combining BiOI with metal-organic frameworks, was developed as catalyst for microplastics degradation. The preparation was modified to achieve the optimal composite catalyst BiOI/MIL-101–40%. The composites exhibited a larger surface area, superior photo-activity, and a distinct heterojunction structure, which accelerated the separation of electrons and holes. Besides, the inclusion of Fe(II) within MIL-101 could construct a photo-Fenton reaction upon the addition of H2O2 in the solution. The carbonyl index of treated polyethylene microplastics increased by 0.127 after 6 h reaction, which was 5.3 and 3.7 times higher than monomer BiOI and MIL-101, respectively. Efficient electron-hole separation and Fe(III)/Fe(II) conversion improved the rate-limiting step of the Fenton process, leading to a synergistic effect between photocatalysis and Fenton reaction, significantly enhancing PE degradation efficiency. Electron spin resonance spectroscopy and selective radical quenching experiments were performed to detect the active components, and the main active species proved to be the hydroxyl radical and the hole. The band structure of the photocatalyst and intermediate products in the reaction solution were subsequently analyzed, leading to the inference of potential reaction mechanisms and pathways. The catalyst-built Fenton system demonstrated outstanding proficiency even under alternating light and dark conditions. The extracted microplastic samples also confirmed the feasibility of this system for complex samples. In conclusion, this study highlighted a green and efficient approach that may be used in future industrial applications to combat microplastic pollution.