Polyvinyl Chloride Microplastics Research Articles

Degradation of polyvinyl chloride (PVC) microplastics employing the actinobacterial strain Streptomyces gobitricini.

The disposal of plastic materials has resulted in the huge increase of microplastics in the environment. One of the most hazardous plastic waste is polyvinyl chloride (PVC) due to its durability. A tool to remediate PVC microplastic polluted environment might be offered by microorganisms such as Actinobacteria, which has been proven to degrade PVC. Streptomyces gobitricini was isolated from soil polluted by heavy metals and plastic debris and used in a PVC microplastics degradation experiment. Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, and scanning electron microscopy (SEM) were used to study the characteristics of microplastic particles. For the incubation, the optimal pH 7.5 was determined in a preliminary experiment where also pH 5.5 and pH 9.5 were included. Three PVC concentrations (200, 400, and 800mg/L) were incubated in Luria-Bertani broth with S. gobitricini for 90days. After the incubation, PVC-MP particles were recovered by filtering. The percentual weight loss of microplastics was highest (66%) in 200mg/L treatment. Relatively high reductions were observed for the higher microplastic concentrations as well (400mg/L; 65% and 800mg/L; 60%). The bacterial growth decreased in order 200mg/L (3.1 ± 0.1CFU × 105/mL), 400mg/L (3.0 ± 0.0CFU × 105/mL) and 800mg/L treatment (2.7 ± 0.0CFU × 105/mL). High hydrophobicity was observed in all treatments at the end of the incubation indicating the formation of bacterial biofilm on the surfaces of plastic particles. The highest hydrophobicity (84%) associated with the bacterial strain was observed in 200mg/L microplastics treatment. The results show that the bacterium S. gobitricini suits for further studies to reduce PVC microplastic waste in the environment.

Toxic effects of exposure to Polymethyl methacrylate and polyvinyl chloride microplastics in Pacific oysters (Crassostrea gigas)

Increasing attention has been directed toward the toxic effects of microplastics (MP) on marine mollusks in recent years. To evaluate these effects, Pacific oysters (Crassostrea gigas) were acclimated and cultured in a 140-liter container, where two types of MP, polymethyl methacrylate (PMMA) and polyvinyl chloride (PVC), were introduced into their feed. MP concentrations in the water were maintained at 300 μg/L, 600 μg/L, and 900 μg/L to assess oxidative stress, DNA damage, and metabolic disorders in these organisms. Significant alterations in antioxidant enzyme activities were detected in C. gigas exposed to these pollutants. After 30 days of exposure to high concentrations of PMMA, superoxide dismutase (SOD) activity in the adductor muscle was reduced by 59% compared to the control group, while catalase (CAT) activity increased by 67%. DNA damage assessments revealed that NF-κB expression levels reached a maximum value of 2.46 in the high-concentration PMMA group after 30 days, the highest among all experimental groups. Additionally, metabolic pathway alterations in the hepatopancreas of C. gigas were observed, including reduced expression levels of uridine and methylmalonic acid (MMA), alongside significantly elevated expression levels of glutamic acid and asparagine. This study offers essential toxicological data for understanding and quantifying the impacts of PMMA and PVC MP on marine mollusks.

Effects of degradable and non-degradable microplastics on SPNEDPR-AGS system: Sludge characteristics, nutrient transformation, key enzyme, and microbial community

The environmental risk of microplastics (MPs) in aerobic granular sludge (AGS) system is unclear. This study evaluates the effects of non-biodegradable polyvinyl chloride microplastics (PVC-MPs) and biodegradable polylactic acid microplastics (PLA-MPs) on AGS systems. The results showed that both destroyed the performance of AGS systems, with PVC-MPs achieving this by disrupting the AGS structure, while PLA-MPs mainly by causing the expansion of filamentous bacteria induced through the stimulation by lactic acid metabolite (R0: 5.52 ± 0.49 μg/L; RPLA5: 11.67 ± 0.56 μg/L). Moreover, both MPs inhibited nitrogen removal by disrupting partial nitrification and endogenous denitrification and suppressed key microbes such as Candidatus Competibacter and Nitrosomonas. Metabolic pathway analysis and molecular docking have further confirmed the mechanisms by which MPs affect critical metabolic pathways and key enzymes. Consequently, the hazards of biodegradable MPs to the stable operation of sewage treatment plants should also be of concern.

Differential Effects of Polyvinyl Chloride Microplastics and Kaolin Particles on Gut Immunity of Mussels at Environmental Concentrations

Both microplastics (MPs) and kaolin are marine suspended particles capable of influencing the physiology of bivalve mollusks. However, the current research on MPs lacks the analysis of their own physical and chemical toxicity, and the comparative study of the toxicity of microplastics and natural suspended particles (NSPs) in aquatic environment. In this work, three experiments are layered, with Experiment 1 directly comparing MPs PVC and kaolin and showing that MPs have greater deleterious effects on thick-shelled mussels than kaolin, with the exception of physical damage and effects on gut microorganisms. As the presence or absence of chemicals may be the main difference between MPs and kaolin, in Experiment 2 the toxicity drivers of MPs PVC itself were investigated, demonstrating that the chemicals in MPs are indeed toxic and that the harmful effects of MPs on mussels may be due to the superposition of their own physical and chemical toxicity. Finally, in Experiment 3 mussels were exposed to the chemicals in MPs and kaolin in a composite and found that the toxicity of the composite exposure was greater than that of the single exposure to kaolin, suggesting that the chemicals may be the main factor contributing to the difference in toxicity between MPs and kaolin. In conclusion, this work addresses the lack of a natural particle control group in current studies of MPs, confirms that the toxicity drivers of MPs are due to both physical and chemical factors, highlights the role of natural suspended particles in the environment, and provides new insights for evaluating the toxic effects of MPs in the natural marine environment.

Significance of Morphology in Characterizing Human Health Risk from di(2-ethylhexyl) Phthalate in Polyvinyl Chloride Microplastics in Groundwater

In this study, a human health risk assessment was performed on the ingestion route of groundwater containing polyvinyl chloride (PVC) microplastics (MPs), and the carcinogenic and non-carcinogenic risks of di(2-ethylhexyl) phthalate (DEHP), a representative additive, were determined. In particular, the impact of volume diversity according to the shape (morphology) of PVC MP (fragment, fiber, film) on the risk characterization was intensively explored. Firstly, a continuous particle size distribution following a power function was derived using the abundance ratio of PVC MPs by size in the investigated groundwater, and human health risk assessment for DEHP in the PVC MPs was performed through the volume distribution according to the shape of MPs. DEHP human health risk assessment showed an excess cancer risk (ECR) of below 10−6 for a 95% cumulative probability for all MP shapes, but the values varied depending on the shape. Sensitivity analysis showed that the parameter that most affected human health risk was MP volume, second to concentration, which is dependent on MP shape. Therefore, it is necessary to consider the variety of MP shapes during human health risk assessment, and it can be achieved through probabilistic risk assessment utilizing the probability distribution for size and shape of MPs.

Revealing the responses of sludge characteristics and microbial metabolic pathways to polyvinyl chloride microplastics in an AnSBR-ASBR system

Revealing the responses of sludge characteristics and microbial metabolic pathways to polyvinyl chloride microplastics in an AnSBR-ASBR system

The Adsorption Process and Mechanism of Benzo[a]pyrene in Agricultural Soil Mediated by Microplastics.

The coexistence of microplastics and benzo[a]pyrene (BaP) in the environment, and their interactions within agricultural soils in particular, have garnered widespread attention. This study focused on the early-stage interactions between microplastics and BaP, aiming to uncover their initial adsorption mechanisms. Despite the significant environmental toxicity of both pollutants, research on their mutual interactions in soil is still limited. This study conducted adsorption thermodynamics and kinetics experiments to explore the effects and mechanisms of various microplastics (polyethylene (PE), polystyrene (PS), and polyvinyl chloride (PVC)) on the adsorption of BaP. Using advanced techniques such as scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy, this study explored the surface characteristics of microplastics and their interactions with BaP. The results demonstrated that PVC microplastics exhibited the highest adsorption capacity for BaP, which was primarily due to π-π interactions and increased hydrophobicity. In the soil-microplastic blend systems, BaP was predominantly found on microplastics, enhancing the soil's adsorption capacity for BaP, particularly PVC, which showed an adsorption capacity 3.69 times greater than that of soil alone. Density functional theory (DFT) simulation calculations indicated that the binding energy of BaP for PVC pretreated with soil was -59.16 kJ/mol, whereas it was -53.02 kJ/mol for untreated PVC, -39.35 kJ/mol for PE, and -48.84 kJ/mol for PS. These findings suggest that soil pretreatment enhances the adsorption stability of PVC for BaP, further elucidating the potential mechanisms behind the increased adsorption capacity in the soil-microplastic system. These findings confirm that microplastics serve as effective vectors for organic pollutants such as BaP, significantly influencing their environmental behavior in soils, and provide essential theoretical support for assessing the environmental toxicity and migration behaviors of microplastics and associated organic contaminants.

Tailoring porous NiMoO4 nanotube via MoO3 nanorod precursor for environmental monitoring: Electrochemical detection of micro-sized polyvinylchloride

Globally, the hidden contaminants like microplastics (MPs) combined with other harmful substances have agglomerated in rivers and oceans that pose a threat to human health. Thus, evaluating the toxicity of MPs separately and in combination with other pollutants must be done quickly and precisely. This work reports the synthesis of porous NiMoO4 nanotubes (NTs) from the transformation of MoO3 nanorods (NRs) via two steps hydrothermal methods for the effective detection of polyvinyl chloride (PVC) MPs. Transformation of MoO3 NRs to porous NiMoO4 NTs was comprehensively deduced by evaluating the crystalline, structural, compositional and morphological properties. The hydrophobic nature of MoO3 NRs and porous NiMoO4 NTs was proven experimentally and also by DFT calculations. The electrochemical detection of PVC MPs by NiMoO4 NTs was investigated by the CV and EIS measurements. Porous NiMoO4 NTs based electrode expressed the good detection towards PVC MPs with a reasonable sensitivity of ∼1.43 × 10−4 μA/ppm.cm2, a low LOD of ∼18 ppm and R2 = ∼0.9781. EIS results revealed that porous NiMoO4 NTs electrode enabled to deliver sensing response at very low concentration of PVC MPs. Due to their easy interaction with hydrophobic PVC MPs, the hydrophobic NiMoO4 NTs controlled the sensing nature of the material and improved the electrochemical detection at the MP-NiMiO4 NTs interface.

Aging Dynamics of Polyvinyl Chloride Microplastics in Three Soils with Different Properties.

Microplastic (MP) contamination in soil has been of great concern, but the dynamic aging process and potential pathways of MPs in natural soil systems remain poorly understood. Herein, poly(vinyl chloride) microplastics (5% w/w) were weathered for 12 months in sandy soil, silty clay, and silt loam. The results showed that the continuous increase of C═O and O-H groups (rate constant, k = 0.080-0.424 m-1) with time was observed on the surface of MPs aging in sandy soil due to the leading role of •OH induced by light irradiation. In the loam soil, the abundant coating of aluminosilicates and iron oxides on the MP surface by the formation of mineral-hydroxyl groups inhibited the generation of the C═O group (k < 0.165 m-1). The k of the characteristic bond C-Cl during the first 9 months was 9.51 and 1.93 times higher in clay compared to that in sandy and loam soil, respectively, revealing that dechlorination triggered the first step of the aging process for MPs in clay owing to the participation of degrading bacteria (Phenylobacterium and Caulobacteraceae). The results provide important insights into the aging dynamics of MPs in environmentally realistic circumstance, which account for understanding the different aging processes of MPs in different soils.

Cadmium and polyvinyl chloride microplastics induce mitochondrial damage and apoptosis under oxidative stress in duck kidney

Polyvinyl chloride microplastics (PVC-MPs) and Cadmium (Cd) are widely occurring water pollutants that interact with each other to exert toxic effects. As a waterfowl, Muscovy duck is more susceptible to PVC-MPs and Cd than land poultry. In this study, Muscovy duck was used as a research model, and 10 mg/L PVC-MPs and 50 mg/kg Cd were used alone and in combine to explore the effect on the kidney of Muscovy duck. We found that treatment of Cd or PVC-MPs alone changed the kidney weight, increased creatinine and urea nitrogen content, and disrupted oxidative balance and macro/trace element metabolism, while the combination of PVC-MPs+Cd reduced the accumulation of Cd in the kidney. In addition, treatment of Cd and PVC-MPs alone caused mitochondrial damage, increase or decrease of mitochondria-associated proteins (Fis1, Drp1, PGC-1α, Nrf1), and Nrf2 signaling pathway plays a key role in detoxification and alleviation of oxidative stress, and we found that PVC-MPs+Cd treatment recovered related proteins (Nrf2, Keap-1, HO-1, NQO1, AC-SOD2, SOD2) compared with the Cd and PVC-MPs alone treatment. Finally, we detected changes in apoptosis-related proteins and genes (Caspase-3, Caspase-9, Bax, Bcl-2, Cytc) and TUNEL staining, and after PVC-MPs+Cd treatment, apoptosis-related proteins/genes recovered and the apoptosis rate decreased compared with the Cd and PVC-MPs alone treatment. These results indicate that renal function is impaired, oxidative stress and trace element metabolism disorder, nuclear factor-E2 related factor 2 (Nrf2) is activated into the nucleus to induce the expression of related antioxidant proteins (such as HO-1, NQO1). These injuries can induce mitochondrial damage and eventually lead to renal cell apoptosis. To sum up, these evidence show that Cd or PVC-MPs can induce kidney oxidative damage, trace element metabolism disorder, mitochondrial damage and apoptosis.

Negative effects of polyvinyl chloride microplastics and the plasticizer DnOP on earthworms: Co-exposure enhances oxidative stress and immune system damage in earthworms

Polyvinyl chloride microplastics (PVC-MPs) are the most used plastics in agriculture. Di-n-octyl phthalate (DnOP), a commonly used plasticizer in PVC-MPs, may be released from plastic and coexist with PVC-MPs. The effects of DnOP alone and coexisting with PVC-MPs are not known. We evaluated the effects of DnOP or/and PVC-MPs on earthworms, and used integrated biomarker response (IBR) to assess the combined toxicity. Molecular docking and transcriptomics were employed for further interpretation of possible toxicity mechanisms. The results showed that exposure to DnOP or/and PVC-MPs caused oxidative damage and interfered with reproduction, adversely affecting the growth and reproduction of earthworms. IBR results showed that toxicity of DnOP+PVC-MPs exposure was greater than that of DnOP and PVC-MPs exposure alone. DnOP has the ability to directly bind to proteins that are associated with antioxidant enzymes and alter their structure. The transcriptomics results indicated that DnOP and PVC-MPs exposure alone mainly affected growth and development-related pathways, while co-exposure affected apoptosis and immune system-related pathways more. To the best of our knowledge, this is the first comprehensive investigation of the combined toxicity of DnOP or/and PVC-MPs to earthworms from different perspectives, which gives scientifically sound evidence for the rational use of plasticizers DnOP and PVC-MPs.

The effect of polyvinyl chloride microplastics on soil properties, greenhouse gas emission, and element cycling-related genes: Roles of soil bacterial communities and correlation analysis

Different shapes (membranes and particles) and concentrations (1 % (w/w) and 2 % (w/w)) of polyvinyl chloride (PVC) microplastics (MPs) were investigated to determine their impact on the soil environment. The incorporation of MPs can disrupt soil macroaggregates. Compared with 1 % (w/w) MPs, 2 % MPs resulted in a significant increase in soil organic carbon content. MP particles significantly increased soil CO2 emissions, and CH4 emissions were enhanced by both membrane and particle MPs at high concentrations. Microplastics can alter the abundance of Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteriota, and Firmicutes at the phylum level, and Nocardioides, Rhodococcus and Bacillus at the genus level. MP particles had a more significant impact on soil bacterial communities than MP membranes. The relative abundances of genes involved in the C, N, and P cycles were detected by qPCR, and more remarkable changes were observed in MP membrane treatments. The relative abundance of Vicinamibacteraceae and Vicinamibacterales exhibited a positive correlation with most C/N/P cycle-related genes, whereas Pseudarthrobacter and Nocardioides demonstrated a negative correlation. This study highlights that the influence of MPs on soil parameters is mediated by soil microorganisms, providing insight into the effects of MPs on the soil microenvironment.

High doses of polypropylene and polyvinyl chloride microplastics affect the microbial community and nutrient status of vineyard soils

The escalating use of plastic materials in viticulture causes release of microplastics (MPs) into vineyard soils. This study examines the impact on soil health of polypropylene (PP) raffia and polyvinyl chloride (PVC) tube strings, commonly mulched into the topsoil after use. A 120-d incubation experiment was conducted with soils exposed to high doses (10 g/kg) of microplastics (MPs) from standard, new and used strings. The study investigated alterations in the microbial community, bioavailability of macronutrients (NH4+ and NO3−, P, K, Ca, Mg), and bioavailability of micronutrients (Cu, Zn, Fe, Mg). The presence of MPs significantly stressed the soil microbial community, reducing microbial biomass by 30% after 30 d, with the exception of PVC in acid soil, which caused an unexpected increase of about 60%. The metabolic quotient (qCO2) doubled in MP-polluted soils, with PVC exerting a more pronounced effect than PP. Basal respiration increased by 25% relative to the acid control soil. PVC MPs raised soil pH from 6.2 to 7.2 and firmly reduced the bioavailability of micronutrients, particularly in acidic soils, and led to a 98% reduction in nitrate (NO3−). The availability of NH4+, P, K, Mg decreased by 10% and Cu, Fe, Mn, Zn by 30%. However, Ca availability increased by 30%, despite shifting from the acid-soluble fraction to soil organic matter and crystalline minerals. Calcareous soil was generally more resilient to changes than the acid soil. These findings underscore the urgent need to investigate the long-term effects of MPs from viticulture on soil properties and health.

Response of denitrifying anaerobic methane oxidation processes in freshwater and marine sediments to polyvinyl chloride microplastics

Nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) plays a crucial role in mitigating methane (CH4) in natural environments. The increasing presence of microplastics (MPs) in these environments due to human activities is a growing concern. However, the impact of MPs on n-DAMO microorganisms and their role in greenhouse gas regulation, particularly CH4 reduction, remains unclear. This study investigates the effects of polyvinyl chloride (PVC) MPs on n-DAMO activity and the associated microbial communities in freshwater and marine sediments at varying concentrations of (R0/M0-no addition, R1/M1–0.5 %, R2/M2–2%). The results showed that the presence of MPs significantly increased the n-DAMO rate (2.89–3.58 nmol 13CO2 g−1 d−1) compared to the control groups (R0: 1.29 nmol 13CO2 g−1 d−1, M0: 0.11 nmol 13CO2 g−1 d−1), with marine sediments showing a more pronounced response. Additionally, the proportional contribution of nitrate-DAMO processes increased following MP exposure. The presence of PVC MPs also altered the microbial diversity of n-DAMO. Upon the addition of MPs, the microbial community composition of n-DAMO in marine sediments changed more significantly. This study provides the first evidence of a positive impact of PVC MPs on n-DAMO processes, suggesting that the presence of PVC MPs in sediments could potentially contribute to the reduction of CH4 emissions.

Polyvinyl chloride microplastics and drought co-exposure alter rice growth by affecting metabolomics and proteomics

Microplastics, interacting with drought stress, have become threat to crops by altering soil environment. Currently, the effect of combined microplastic and drought stress on crop growth remain poorly understood. In this work, the mechanism of multi-stress responses was investigated under the exposure of polvinylchloride microplastic (PV) and drought (D) individually and in combination (DPV) on rice varieties Hanyou73 and Q280 through proteomics and metabolomic analysis. All treatments negatively affect chlorophyll content, antioxidant enzyme activities, rice grain composition, metabolome and proteomic profiling of both rice varieties. Full rice grain yield was decreased under all treatments except PV treatment in which it was increased in both rice varieties. DPV treatment shows the lowest grain yield and more adverse effects on metabolome by affecting glycerophospholipid metabolism, tryptophan metabolism and alanine, aspartate and glutamate metabolism. Soluble sugar contents were decreased in H73 but in Q280 increased by 159 % under DPV and 123 % in PV treatment, compared to their control group. The results from metabolomics illustrate that glycerophospholipid metabolism is commonly altered in both rice types under all treatments. PV and drought alone and in combination induce extensive alterations in proteomics of rice leaves especially impacting proteins related to binding, translation and photosynthetic process. The results reveal that PV and DPV treatments highly distort the abundance of metabolites and proteins in both rice types, demonstrating that microplastic toxicity effects on rice plants become more severe when combined with drought stress.

Effects of Polyvinyl Chloride Microplastics on the Reproductive System, Intestinal Structure, and Microflora in Male and Female Mice

The pervasive use of plastics in numerous industrial sectors has resulted in the circulation of microplastics across diverse ecosystems and food chains, giving rise to mounting concerns regarding their potential adverse impacts on biological systems and the environment. The objective of this experiment was to investigate the distinct effects of microplastic-polyvinyl chloride (PVC) exposure on the reproductive system, intestinal tissue structure, and intestinal microbial flora of both male and female mice. A total of 24 4-week-old Kunming mice were randomly assigned to one of four groups: male control group (CM), female control group (CF), male PVC test group (PVCM), and female PVC test group (PVCF) (n = 6). The findings revealed that in terms of the reproductive system, the PVCM group exhibited an impaired testicular structure with an irregular arrangement and a significant reduction in spermatogonia, spermatocytes, and spermatozoa within the seminiferous tubules (p &lt; 0.01). The PVCF group exhibited a notable decrease in ovarian follicles (p &lt; 0.01), accompanied by a reduction in uterus volume, fallopian tube volume, and muscle layer thickness, all of which also decreased significantly (p &lt; 0.01). In comparison to the control groups, exposure to PVC resulted in a reduction in the width and height of the intestinal villi, accompanied by an increase in crypt depth. This led to a significant alteration in the ratio of villus height to crypt depth (V/C) (p &lt; 0.01). Moreover, a reduction in microbial species diversity was observed within both the PVCM and PVCF groups; additionally, it was accompanied by contrasting changes in relative abundance and functional gene profiles among the major intestinal flora constituents. In summary, the findings indicate that PVC induces damage to both male and female mice reproductive and digestive systems, further exhibiting notable sex-dependent effects on mouse intestinal microflora composition, which correlates significantly with its impact on reproductive organs.

Enrichment Characteristics and Ecological Risk Prediction of Pathogens on Typical Microplastic Biofilms

As an emerging niche colonized by microorganisms, microplastics may selectively enrich pathogens, resulting in crucial ecological risks and potential threats to public health in aquatic environments. However, the enrichment characteristics and ecological risks of pathogens on different microplastic biofilms remain unclear. In this study, 16S rRNA high-throughput sequencing technology was used to investigate the differences in the bacterial community structure, occurrence characteristics of pathogens, and prediction of ecological risks on five typical microplastic biofilms of polyethylene （PE）, polypropylene （PP）, polystyrene （PS）, polyethylene terephthalate （PET）, and polyvinyl chloride （PVC） through a field in-situ incubation experiment. The results showed that after 28 d of in situ incubation, the macroscopic biofilms were formed on the surface of all microplastics, and the diversity and richness of the bacterial community on all microplastic biofilms were higher than in the surrounding water, indicating that the microorganisms in the surrounding water were selectively enriched on microplastics. Each type of microplastic biofilm had formed a unique bacterial community structure； in particular, PVC microplastics were more inclined to selectively enrich the members of Proteobacteria. A total of 47 human pathogens were identified using the HPB database, including six antibiotic resistance pathogens belonging to the lists of critical priority control. The number and total abundance of human pathogens detected on microplastic biofilm were higher than those in the surrounding water, and the dominant pathogens such as Bartonella, Burkholderia, and Brucella were selectively enriched on microplastic biofilms. Microbial phenotype prediction results based on BugBase showed that three functional phenotypes including biofilm formation, mobile element contained, and potentially pathogenic on microplastic biofilms had significantly increased by 2.38%-5.57%, 0.82%-7.13%, and 3.04%-8.30%, respectively, which were mainly contributed by α-Proteobacteria and γ-Proteobacteria. These results not only indicate that the selective enrichment of opportunistic pathogens on microplastic biofilms may lead to the increased risk of pathogenicity and antibiotic resistance co-spread but also provide reference for the accurate assessment of ecological risks caused by microplastic pollution in aquatic environments.

Investigations on adsorptive removal of PVC microplastics from aqueous solutions using Pinus roxburghii-derived biochar.

This study investigates the adsorption mechanisms of pine bark biochar (BC) and modified pine bark biochar (MBC) in the removal of polyvinyl chloride (PVC) microplastics from aqueous solutions, with a significant focus on resource recovery from pine residues which is one of the key Himalayan Forest byproducts. The research findings highlighted the optimal adsorption capacity of biochar at 131.5mg/g achieved after 6h of contact time, with a pH of 10 and a PVC microplastic concentration of 200mg/L. The primary mechanisms of PVC microplastic adsorption involved ion exchange and physical adsorption, driven by forces such as Vander-Waals, London forces, and electrostatic forces. Thermodynamic analysis showed the exothermic nature of the PVC and BC/MBC interaction, with spontaneous adsorption occurring within the temperature range of 10 to 40°C. Isotherm and kinetic models fit well with Temkin model and PSO kinetics, as indicated by R2 values exceeding 0.9. Particularly, MBC exhibited superior removal efficiency and adsorption capacity compared to its precursor, reaching an optimum adsorption capacity of 156.08mg/g with a removal efficiency of 78%, surpassing the performance of BC. This research contributes valuable insights into potential applications of BC for PVC removal and underscores the effectiveness of MBC in achieving enhanced adsorption outcomes.

The Study of Removal of Polyvinyl Chloride (PVC) Particles from Wastewater through Electrocoagulation

Plastic was produced massively, especially using polyvinyl chloride (PVC) as a raw material. Unfortunately, this condition cause affects the environment, which creates a new pollutant issue. It is essential to study the removal of PVC microplastics in current water treatment processes. The study of wastewater treatment can be achieved using electrocoagulation, which has several benefits, including low-cost, simple chemicals, and accessible equipment operation. This research investigated the study of the removal of PVC microplastics from wastewater by electrocoagulation. The new potential of the electrocoagulation technique using Al-Al electrodes was studied systematically at various variations, i.e., electrolysis time, electrolyte concentration, initial pH, coagulation speed, and electrolyte type. The results showed that the PVC microplastics removal efficiency reached 100% after electrolysis for 60 min, electrolyte concentration of 0.01 mol/L, initial pH of 7, coagulation speed of 500 rpm, the type of electrolyte used was NaCl at a flocculation speed. These optimum conditions also reduced the value of turbidity of wastewater samples from 1.39 ± 0.02 to 1.10 ± 0.05 NTU. The results of this study provide an engineering perspective in optimizing operational parameters for removing PVC microplastics in aquatic environments.

Presence of microplastics enhanced the toxicity of silver nanoparticles on the collembolan Folsomia candida

There is growing interest in interactions of microplastics (MPs) with other pollutants. However, there is limited understanding of the combined effects of MPs and silver nanoparticles (AgNPs) on nontarget soil organisms. This work aimed to examine the effects of exposure to various AgNPs' concentrations alone (0, 0.1, 1, 10, 100, 1000 mg kg−1, 50 nm) and in combination with polyvinyl chloride microplastics (PVC MPs, 80−250 μm) at 0.1% concentration for 28 days on reproduction, Ag accumulation, C/N ratio, and isotopic fractionation of the standard soil fauna collembolan Folsomia candida. Results showed that compared to the AgNPs exposure alone, the presence of MPs significantly reduced reproduction by 51.4% and markedly increased Ag content in collembolans by 87.7% at 1000 mg kg−1 AgNPs, which evidenced a synergistic effect. Co-exposure to MPs and AgNPs resulted in a noticeable reduction in the C/N ratio in F. candida body tissues by 9.90% and 5.27% at 1 and 10 mg kg−1 AgNPs, respectively, showing additive and synergistic effects. Additionally, this co-exposure altered stable isotope fractionation, with the highest increments of δ15N by 32.3% and inhibition of δ13C by 2.62%, demonstrating the turnover of nutrients shift in the collembolan tissues. Collectively, this study demonstrates that con-current exposure to environmentally relevant concentration of MPs and relatively high doses of AgNPs synergistically induces toxic effects on F. candida, leading to Ag accumulation and reproduction decline. These findings imply that MPs could alter collembolans' responses to AgNPs exposure, potentially enhancing the metal ions’ bioavailability in soil environments and posing ecotoxicological threats to soil-dwelling organisms.