Efficient magnetic capture of PE microplastic from water by PEG modified Fe3O4 nanoparticles: Performance, kinetics, isotherms and influence factors.

Due to their resistance to degradation, wide distribution, easy diffusion and potential uptake by organisms, microplastics (MPs) pollution has become a major environmental concern. In this study, PEG-modified Fe3O4 magnetic nanoparticles demonstrated superior adsorption efficiency against polyethylene (PE) microspheres compared to other adsorbents (bare Fe3O4, PEI/Fe3O4 and CA/Fe3O4). The maximum adsorption capacity of PE was found to be 2203 mg/g by adsorption isotherm analysis. PEG/Fe3O4 maintained a high adsorption capacity even at low temperature (5°C, 2163 mg/g), while neutral pH was favorable for MP adsorption. The presence of anions (Cl-, SO42-, HCO3-, NO3-) and of humic acids inhibited the adsorption of MPs. It is proposed that the adsorption process was mainly driven by intermolecular hydrogen bonding. Overall, the study demonstrated that PEG/Fe3O4 can potentially be used as an efficient control against MPs, thus improving the quality of the aquatic environment and of our water resources.

Occurrence and characteristics of microplastics across the watershed of the world's third-largest river.

While rivers as primary conduits for land-based plastic particles transferring to their "ultimate" destination, the ocean, have garnered increasing attention, research on microplastic pollution at the scale of whole large river basins remains limited. Here we conducted a large-scale investigation of microplastic contamination in water and sediment of the world's third-largest river, the Yangtze River. We found concentrations of microplastics in water and sediment to be 5.13 items/L and 113.9 items/kg (dry weight), respectively. Moreover, microplastic pollution levels exhibited a clear decreasing trend from upstream to downstream. The detected microplastics were predominantly transparent in color, with fibrous shapes predominating, sizes mainly concentrated below 1 mm and composed primarily of PP and PE polymers. Our analysis results indicated that compared to geographical and water quality parameters, anthropogenic factors primarily determined the spatial distribution pattern of microplastics. Moreover, the microplastic abundance in sediment upstream of the dam was significantly higher than that in the downstream sediment, while the trend of microplastic concentrations in water was opposite. Therefore, more effort is needed to monitor microplastic contamination and their ecological environmental effects of sediment before dams in future research.

How much do we know about the microplastic distribution in the Mediterranean Sea: A comprehensive review.

The Mediterranean Sea is one of the most heavily polluted regions. Here we comprehensively review the current state of microplastic pollution in the Mediterranean Sea and the Black Sea. A total of 284 studies published between 2012 and 2023 were analyzed, revealing a continuous increase in research efforts. Our review encompassed microplastic monitoring studies across five environmental matrices: the sea surface, water column, intertidal sediment, bottom sediment, and biota, with a predominant focus observed in biota-related studies with fish, molluscs, crustaceans, and echinoderms being the primary focus. The study found that species such as Mullus barbatus, Mytilus galloprovincialis, Nephrops norvegicus, and Holothuria tubulosa are frequently studied species. The review also emphasizes the lack of standardized methodologies across studies, which hampers the comparability of results and the synthesis of data. The findings of this study provide a critical evaluation of the current research landscape and identify significant knowledge gaps, particularly in the underrepresented southern Mediterranean and Black Sea regions, calling for more balanced research efforts and methodological consistency in future studies.

Seasonal variability of microplastic contamination in marine fishes of the state of Gujarat, India.

Seasonal variation in microplastics abundance, occurrence, and distribution in pelagic and demersal fishes was observed in this study during December 2021 to November 2022. One hundred percent presence of microplastic in inedible (gut and gills) tissue, while 82% and 54% in edible tissue (muscle) of pelagic and demersal fishes respectively were seen. Post-monsoon period showed high prevalence of microplastics followed by monsoon and the least during pre-monsoon in both pelagic and demersal fishes. In pelagic fishes, the edible tissue had microplastics abundance of 1.56 to 13.34 numbers per 10 g of tissue whereas inedible tissue had 3.36 to 16.67 numbers per 10 g of tissue. In demersal fishes, the edible tissue had microplastics abundance of 1.04 to 5.26 numbers per 10 g of tissue while it was 2.67 to 8.34 numbers per 10 g of inedible tissue. There was significant variation in abundance of microplastic in edible and inedible tissue of all the fishes (Mann-Whitney test, p < 0.05). The most dominant microplastics size was 0.005-0.05 mm followed by 0.05-0.5 mm and the least of greater than 0.5 mm in pelagic and demersal fishes respectively. Taking microplastic shape into consideration, the most dominant was fiber followed by fragment and the film in inedible tissue of all the fishes. The edible tissue of all the fishes had only fiber in them (100% occurrence). The dominance of blue color microplastics was observed followed by red, green, yellow, and orange at least in edible as well as inedible tissues of the fishes. More than 99% microplastics polymer observed in this study include polyethylene (PE), polypropylene (PP), and polystyrene (PS); only less than 1% was unidentified. This is the first study done on seasonal variation of microplastic in the marine fish population of Gujarat waters, Northeast Arabian Sea. The study highlights the nature of micro-pollutant in marine environments, emphasizing the need for comprehensive monitoring and management strategies.

High-efficiency microplastic removal in water treatment based on short flow control of hydrocyclone: Mechanism and performance.

Microplastics have been identified as a potentially emerging threat to water environment and human health. Therefore, there is a pressing demand for effective strategies to remove microplastics from water. Hydrocyclone offers a rapid separation and low energy consumption alternative but require reduction of microparticle entrainment by short flow, which limits the effectiveness for small density differentials and ultralow concentrations separation. We proposed an enhanced mini-hydrocyclone with overflow microchannels (0.72 mm width) based on the active control of short flow in hydrocyclone for microplastic removal from water. The overflow microchannels effectively redirect the particles that would typically be entrained by the short flow, leading to higher separation efficiency. Simulation results show overflow microchannels effectively reduced short flow to 0.7 %, a reduction of up to 94 % compared to conventional hydrocyclones. The hydrocyclone with overflow microchannel demonstrated a removal efficiency exceeding 98 % for 8 µm plastic microbeads at ultralow concentrations (10 ppm), which is a 33.7 % improvement over conventional hydrocyclone. Compared with other methods (e.g., filtration, adsorption, coagulation) for microplastic removal, this work achieves rapid separation capability and long period operation, highlighting hydrocyclone as a promising approach for microplastic removal in industry-scale water treatment.

Microplastic pollution in the surface waters of the zuari river, goa, india.

Limited research has been conducted on microplastic (MP) contamination in the rivers of Goa. To address this gap, this study examines the levels of MP contamination in the surface water of the Zuari River, Goa. We investigate the abundance, characteristics (size, shape, colour, and polymer composition), and risk assessment of MPs. MPs were detected at all sampling stations in the Zuari River, with concentrations varying from 0.01 particles/L (S3) to 1.38 particles/L (S13). The average abundance of MPs in the water samples was 0.28 ± 0.35 particles/L. MPs were more common in the 0.3-1 mm size range (51.70%) than in the 1-5 mm range (48.30%). The most common MP shapes observed were fibers (37.88%) and fragments (29.66%). FTIR analysis confirmed the presence of polyethylene terephthalate, high-density polyethylene, polypropylene, and polyacrylamide carboxyl-modified MPs. The Pollution Load Index (PLI) showed an average value of 3.8, indicating significant contamination (PLI > 1). Scanning electron microscopy (SEM) revealed various degradation features such as pits, scratches, grooves, and cracks on the MPs surfaces, while energy dispersive X-ray spectroscopy (EDS) detected metals on the MP's surfaces. This study provides key insights into MP pollution in the Zuari River's surface water and lays the groundwork for future research and management strategies in the region.

Assessment of microplastic pollution in eleven commercial fish species in the Gulf of Izmir (Aegean Sea, eastern Mediterranean).

With global plastic production reaching 400 million tons in 2022, concerns about plastic pollution in the seas are increasing day by day. Therefore we focused on the abundance, characteristics, and chemical composition of potential anthropogenic origin MPs within the gastrointestinal tracts (GITs) of 11 commercial fish species in the Gulf of Izmir, an area heavily impacted by human activities. Within the scope of the study, 152 fish were sampled, and microplastics were found in 64 fish. In total, 77 MPs were identified based on ATR-FTIR analysis. Significant differences were found between species regarding MP abundance. Among the species, Scomber scombrus showed the highest MP ingestion. The MP abundance in the GIT of fish decreases from surface to deeper waters. There were also significant differences (p < 0.05) in MP abundance between pelagic and demersal fish species. Results showed that 50.6 % of MPs were fragments, and 49.4 % were fibers. The most common color was black. Seven polymer types were identified, and PE was the most common. The size of the identified MPs ranged from 101 to 4901 µm, and the average value was 715.83 ± 860.66 µm. This study sheds light on the MP contamination within commercial fish species in the Gulf of Izmir and emphasizes the urgent need for enhanced marine ecosystem conservation strategies. Our findings can serve as a basis for future studies by providing essential baseline data for implementing necessary policies and regulations.

Record of microplastic deposition revealed by ornithogenic soil and sediment profiles from Ross Island, Antarctica.

Microplastics (MPs) are a global concern as an emerging pollutant, and the investigation on MPs in Antarctic aids in informing their global pollution assessments. Therefore, there are urgent scientific concerns regarding the environmental behavior, origins, influencing factors, and potential hazards of MPs in Antarctica. This study presents the characteristics of MPs from one ornithogenic sediment profile (coded CC) and two ornithogenic soil profiles (coded MR1 and MR2) from ice-free areas on Ross Island, Antarctica. We explored the potential sources of MPs and the main influencing factors for deposition based on their distribution with depth in the profiles. Through laser-infrared imaging spectroscopy (LDIR), a total of 30 polymer types were identified in all samples, with polyethylene terephthalate (PET) and polyvinyl chloride (PVC) as the dominant types, accounting for more than 70% of the total. The abundance of MPs in the CC sediment profile ranged from 2.83 to 394.18 items/g, while in MR1 and MR2 soil profiles, the abundance ranged from 2.25 to 1690.11 and 8.24 to 168.27 items/g, respectively. The size of MPs was mainly concentrated in the range of 20-50 µm, and possible downward movement of certain polymer types was revealed. From the perspective of temporal variation, we suggest that MPs were heavily influenced by local human activities including scientific research, fishing, and tourism, balanced by protective regulations, while no solid evidence was obtained to support strong influence from biological transport through penguins. This research enhances our understanding on the environmental behavior of MPs in the terrestrial systems of remote polar regions.

Diversity but not abundance of ingested plastics changes with ontogenetic dietary shift: Stable isotope insights into plastic contamination in a mesopelagic predator longnose lancetfish Alepisaurus ferox.

We employed Fourier infrared spectroscopy, laser infrared technology, and stable isotope analysis to investigate the relationships between characteristics of ingested plastics and size-related feeding ecology of a mesopelagic predator, longnose lancetfish Alepisaurus ferox. Plastics were detected in 81.48 % of specimens, up to 8.81 ± 8.29 items/individual and 0.59 ± 0.66 items/g wet weight of intestine, and were sized 20.00 µm to 6.50 cm. The majority were granules and fragments in shape, and polystyrene and acrylate copolymer in polymer type. The diversity indices exhibited a correlation with trophic position and body size groups, emphasizing that the ontogenetic dietary shift of A. ferox may influence the diversity of plastics ingested. This study provides new insights into the plastic pathways linking epipelagic and mesopelagic food webs and demonstrates that biochemical ecological tracers can effectively indicate the bioavailability of plastic correlated with growth in mesopelagic predator.

Synergetic effects of chlorinated paraffins and microplastics on microbial communities and nitrogen cycling in deep-sea cold seep sediments.

Chlorinated paraffins (CPs) and microplastics (MPs) are commonly found in deep-sea cold seep sediments, where nitrogen cycling processes frequently occur. However, little is known about their combined effects on sedimentary microbial communities and nitrogen cycling in these environments. This study aimed to investigate the synergistic impacts of CPs and MPs on microbial communities and nitrogen cycling in deep-sea cold seep sediments through microcosm experiments. Our results demonstrated that the presence of CPs and MPs induced significant alterations in microbial community composition, promoting the growth of Halomonas. Furthermore, CPs and MPs were found to enhance nitrification, denitrification and anammox processes, which was evidenced by the higher abundance of genes associated with nitrification and denitrification, as well as increased activity of denitrification and anammox in the CPs and MPs-treatment groups compared to the control group. Additionally, the enhanced influence of CPs and MPs on denitrification was expected to promote nitrate-dependent and sulfate-dependent anaerobic oxidation of methane, thereby resulting in less methane released into the environment. These findings shed light on the potential consequences of simultaneous exposure to CPs and MPs on biogeochemical nitrogen cycling in deep-sea cold seep sediments.

Microplastics in commercial bivalves from coastal areas of Thailand and health risk associated with microplastics in ingested bivalves.

Microplastics (MPs) contamination in marine organisms is a significant threat to seafood consumers worldwide. This study is the first to investigate the abundance of MPs in the commercial bivalves from six sites along Thailand's coastline, the daily exposure of bivalve consumers to MPs, and potential associated health risks. The microplastic occurrence varied from 69 % to 93 % in four bivalve species while the average abundance of MPs was 1.87 ± 0.86 items/individual or 0.46 ± 0.43 items/g ww. Benthic bivalves (cockles and clams) contained more MPs than their pelagic counterparts (mussels and oysters). Small blue microfibers (<500 µm) were the most abundant. The most common polymers were natural based polymers (cotton and rayon) and polyethylene terephthalate (PET). The daily microplastic exposure for consumers was 0.52 items/person. Although the risk of microplastic contamination is low, we recommend investigation into the transfer of MPs within the food web, notably as it may pose significant human health concerns.

Modeling the differential functional responses and selectivity of a marine copepod to nano/microplastics in mixture.

Nano- and microplastics (NMPs) pollution is widespread in the oceans, posing potential risks to marine species. This study examined the accumulation capacity and selectivity potentials of NMPs by a marine copepod Parvocalanus crassirostris under different food mixtures by modeling the combined biokinetic and functional response. We investigated two sizes of NMPs (200 nm and 5 µm) across a concentration gradient (0 - 5000 µg/L) and varying diatom abundances (0, 104, 105 cells/mL). Fluorescence imaging and quantification revealed that P. crassirostris actively ingested NMPs at low concentration. Accumulation increased with NMPs concentration but eventually saturated due to gut capacity limits, following a Holling type II functional response (i.e., hyperbolic curve). Our novel functional response model estimated the key parameters and demonstrated that the maximum accumulation reached 5.3 % of dry weight with averaged half-saturation constants of 229 µg/L. The size of NMPs did not significantly affect the total accumulation or satiety levels. The presence of diatoms influenced the feeding selectivity and decreased the microplastic accumulation by 73 % at 105 cells/mL, while facilitating nanoplastic accumulation by 81 % at 104 cells/mL. This study enhanced our understanding of NMPs bioavailability and environmental fate in marine ecosystems.

Synergistic effects between microplastics and glyphosate on honey bee larvae.

Microplastic (MPs) pollution has emerged as a global ecological concern, however, the impact of MPs exposure, particularly in conjunction with other pollutants such as glyphosate (GLY) on honey bee remains unknown. This study investigated the effects of exposure to different concentrations of MPs and their combination with GLY on honey bee larvae development, or during the larvae period, regulation of major detoxification, antioxidant and immune genes, and oxidative stress biomarkers. Results revealed that combined exposure to MPs and GLY decreased larvae survivorship and weight, while exposure to MPs alone showed no significant differences. Both MPs and GLY alone downregulated the defensin-1 gene, but only combined exposure with GLY downregulated the hymenoptaecin gene and increased catalase enzyme activity. The data suggest a synergistic effect of MPs and GLY, leading to immunosuppression and reduced larvae survival and weight. These findings highlight potential risks of two prevalent environmental pollutants on honey bee health.

Influence of cephalexin on cadmium adsorption onto microplastic particles in water: Human health risk evaluation.

This paper explores the impact of environmental factors on the adsorption of cadmium (Cd) and cephalexin (CEX) onto polyethylene (PE) microplastics. The study focused on Cd adsorption behavior on microplastics (MPs) of various sizes, revealing that particles sized 30-63 µm exhibited the highest adsorption capacity compared to other sizes. Cd sorption was significantly influenced by initial pH and salinity levels. Experimental data closely matched both the Langmuir (R2 > 0.91) and Freundlich (R2 > 0.92) isotherms. Cd adsorption onto PE particles was greater than CEX adsorption, with the maximum Cd uptake capacity measured at 1.8 mg/g. FTIR analysis indicated that Cd and CEX adsorption onto MPs was likely governed by physical interactions, as no new functional groups were detected post-uptake. The desorption rates of Cd and CEX from PE microplastics were evaluated in various liquids, including aqueous solution, tap water, seawater, and synthetic gastric juice. The health risks associated with Cd, in combination with MPs and CEX, for both children and adults were assessed in groundwater and aqueous solutions. This study offers scientific insights and guidelines for examining the environmental behavior, migration, and transformation of microplastics and their related ecological risks in scenarios of combined pollution.

The comparison effect on earthworms between conventional and biodegradable microplastics.

Many studies have reported the toxic effects of microplastics (MPs) on organisms, especially on how conventional plastics affect organisms after short-term exposure. The effects of biodegradable plastics on organisms are, however, largely unexplored, especially concerning their impact after long-term exposure. We perform a series of experiments to examine the effects of conventional (polyethylene (PE)) and biodegradable (polylactic acid (PLA)) microplastics on earthworms at three concentrations (0.5 %, 2 %, and 5 % (w/w)) and particle sizes (149, 28, and 13 µm) over short- (14 d) and long-term (28 d) periods of exposure. Negative effects on earthworms are more pronounced following exposure to PE than PLA, particularly over the shorter term. After longer-term exposure, earthworms may adapt to PE and PLA environments. A close relationship exists between the effects of MPs on earthworms and activities of superoxide dismutase, catalase, and malondialdehyde enzymes, which we use to evaluate the degree of antioxidant damage. We report both PE and PLA to negatively affect earthworms, but for the effects of PLA to be less severe after longer-term exposure. Further investigation is required to more fully assess the potential negative effects of PLA use on soil organisms in agriculture.

Aging of drinking water transmission pipes during long-term operation as a potential source of nano- and microplastics.

Microplastics (MPs) and nanoplastics (NPs) released into drinking water from transmission pipes can pose a potential health risk to consumers. This paper presents the results of a comprehensive study of PE and PVC pipes after long-term operation in drinking water distribution networks, which confirmed that degradable polymers can be a significant source of MPs. Both plastics age relatively quickly, and the degree of damage to the pipe surface depends on the time and operating conditions. During aging, polymer chains deteriorate, leading to a weakening of the structure and increased amorphousness of the plastics. As a result, the surfaces of PE and PVC crack and peel, resulting in the formation of particles with sizes corresponding to NP and MP with high potential for release into water. The magnitude of the phenomenon increases as the diameter of the pipes decreases, indicating that the most vulnerable customers are those at the ends of the network to which drinking water is supplied through small-diameter pipes. Aging PE and PVC pipes should be considered a real and very important source of MPs and NPs in drinking water, and water quality in this aspect should be monitored by manufacturers.

Direct monitoring of the enzymatically sequestering and degrading of PET microplastics using hyperspectral Raman microscopy.

Microplastics are commonly referred to as tiny plastic fragments polluting our environment, although their nanometric forms have also been found in our drinking water supplies and many living systems. Their removal is relevant for preserving our health and sustainability and is being pursued according to many different strategies, including filtration through selective porous materials or agglomeration using flocculant agents. An alternative nanotechnological approach described in this paper deals with the capture and degradation of micro and nanoplastics by enzyme-immobilized magnetic nanoparticles. Magnetic nanoparticles (Fe3O4) were functionalized with polydopamine (PDA) and Lipase enzyme straightforwardly to generate agents capable of removing and degrading µPET from an aqueous solution. In addition to synthesizing and characterizing the Fe3O4@PDA-Lipase nanoparticles and performing the µPET degradation, the novelty encompassed in this work is the successful use of confocal Raman microscopy to monitor the process, in real-time, through in situ hyperspectral images.

Evaluating physiological responses of microalgae towards environmentally coexisting microplastics: A meta-analysis.

Microplastics (MPs) are abundantly present in aquatic environments, where the phytoplankton-microalgae, are now inevitably bound to a long-term coexistence with them. While numerous studies have focused on the toxicological effects of high-concentration MPs exposure, there remains controversy over whether and how MPs affect microalgae at environmentally relevant concentrations. This study aims to draw conclusions that narrow the gap from 52 studies with varying results. Overall, MPs can inhibit growth and photosynthesis, induce oxidative damage, from which microalgae can recover after an appropriate period. Cyanobacteria exhibit greater vulnerability than chlorophyta. The relative size of MPs to algal cells potentially governs their coexistence behavior, thereby altering the mechanisms of impact. Pristine MPs may increase the production of extracellular polymeric substances (EPS) and microcystins (MCs), while aged MPs have the opposite effect. Additionally, relevant factors are systematically discussed, offering insights for future research.

A new holistic perspective to assess the ecological risk of microplastics: A case study in Baiyangdian Basin, China.

By integrating probabilistic ecological risk assessment with the overall risk index method, which considers the multidimensional characteristics of the microplastome, the ecological risks of microplastic pollution were assessed more comprehensively. This study took the Baiyangdian Basin as an example to address the limitations of current risk assessment methods that rely on concentration data or the individual risk of microplastics. Using an exponential regression model, the acute and chronic ecological risk thresholds for the overall risk index method were determined to be 0.43 and 0.30, respectively. The acute and chronic ecological risks of the microplastome occupied 61 % and 79 % of the Baiyangdian Wetland and 0 % and 14 % of the Fu River, while the Xiaoyi River did not exhibit risk during the rainy season. Results indicated that intense human activities, poor hydrodynamics, low settling velocity and high levels of environmental chemical pollutants jointly contributed to the high risk of the microplastome in water bodies. Compared with the probabilistic ecological risk assessment method (risk characterization ratio), there was a significant difference in the area of acute and chronic ecological risks caused by the microplastome in the Baiyangdian Basin when using the overall risk index method. This proved that considering only concentration cannot truly reflect the toxicity of microplastics to aquatic organisms.

Microplastic injection? Identification and quantification of plastic particles in medical injections.

Microplastics (MPs) mainly enter the human body through ingestion and breathing. Most of them are excreted through feces, and only a small amount can accumulate in human organs and tissues. In contrast, if intravenous injection contains MPs, it could directly enter bloodstream and maybe pose severe health risk. To verify this hypothesis, we collected two types of injection [0.9 % NaCl and 5 % Glucose] with three dominant brands in China, to analyze the possible MPs. The results indicated that the injection had an average abundance of 895 MP particles/kg, ranging from 140 to 1840 particles/kg. Furthermore, more MPs were found in NaCl than Glucose injection. The MPs encompassed 21 types of polymers with notable brand variations in distribution. Notably, polyisoprene chlorinated (61.77 % in NaCl, 61.23 % in Glucose) are most prevalent. Most polymers had small diameter, with 30.5 % and 44.2 % of particles measuring between 0 and 30 µm in NaCl and Glucose injection, respectively. These minute particle sizes contribute to the dispersal of MPs within human tissues. In terms of shape, most polymers are fibers/fragments, with some in bead form. Our study uncovered a previously unnoticed but important pathway for MPs enter the human body, emphasizing the need to evaluate health risks of infusion-related MP.