Major Environmental Pollutant Research Articles

Comparison of immune defense and antioxidant capacity between broodstock and hybrid offspring of juvenile shrimp (Macrobrachium nipponense): Response to acute ammonia stress

Ammonia is a major environmental pollutant in the aquatic system that poses a great threat to the health of shrimp. Macrobrachium nipponense, as one of the large-yield farmed shrimp, is facing germplasm degradation. Genetic improvement through hybridization is one of the effective methods to solve this problem. However, there are few studies on the effects of ammonia nitrogen on the germplasm resources of M.nipponense. In this study, the broodstock populations (Dianshan, DS) and hybrid offspring (DS ♀×CD [Changjiang, CJ ♂×Dongting, DT ♀], SCD) were exposed to 0, 5, or 20mg/L of ammonia for 96h. The survival rate of the SCD group was greater than the DS group, although there were no significant differences in weight gain rate and length gain rate (p>0.05). The number of positive cells and apoptosis rates in the DS group were significantly greater than in the SCD group after ammonia exposure (p<0.05). As the ammonia concentration increased, the antioxidant enzyme activities in the SCD group were significantly higher than DS group, while the hepatotoxicity enzyme activities in the SCD group were significantly lower than DS group (p<0.05). The trends in the expression of antioxidant- and immune-related genes were generally consistent with the activities of antioxidant enzymes. Our study found that the hybrid population had stronger stress resistance than their parent populations at the same ammonia concentration. This study confirms our speculation that hybrid population has a greater advantage in antioxidant immunity, which also provides reference for the follow-up study of chronic ammonia toxicity.

Impact of Sodium Arsenate on Histological Changes in Liver and Kidney of Fresh Water Catfish, Clarias batrachus

Background: In new age, Arsenic is a major environmental pollutant and exposure occurs through agricultural, environmental, medicinal and occupational sources. The toxicity of sodium arsenate has been shown in catfish, Clarias batrachus and the histology report suggested that the sodium arsenate may adversely effect on the catfish, Clarias batrachus. Methods: The histological analysis carried out during the period of 2018-19 for sodium arsenate with Clarias batrachus as test animal for 96 hour as per ideal method and determine the lethal concentration (LC50). The liver and kidney tissues were collected from the fishes exposed to sodium arsenate and standard histology procedure were followed to investigate the histological alterations. Result: Exposure of sodium arsenate causes severe histological changes in liver like nucleus blabbing, infiltration, necrosis of hepatocytes, disruption of normal architecture, shrunkeri hepatocytes, lytic hepatocytes etc. In kidney sodium arsenate exposure causes hemorrhage, inflammation and tubular atrophy in renal tubules, disruption of tubular linings, dense chronic inflammation, hemorrhage and vacoulation in Bowman’s capsule etc. The present investigation suggests that the inorganic forms of arsenic showing the highest toxicity level.

Isolation and characterization of a recombinant class C acid phosphatase from Sphingobium sp. RSMS strain

Tributyl phosphate (TBP) is extensively used in nuclear industry and is a major environmental pollutant. The mechanism for TBP degradation is not identified in any TBP-degrading bacteria. Here, we report identification of an acid phosphatase from Sphingobium sp. RSMS (Aps) that exhibits high specific activity towards monobutyl phosphate (MBP) and could be a terminal component of the TBP degradation process. A genomic DNA library of the bacteria was screened using a histochemical method which yielded 35 phosphatase clones. Among these, the clone that showed the highest MBP degradation was studied further. DNA sequence analysis showed that the genomic insert encodes a protein (Aps) which belongs to class C acid phosphatase. The recombinant Aps was found to be a dimer and hydrolysed MBP with a Kcat 68.1 ± 5.46 s−1 and Km 2.5 mM ± 0.50. The protein was found to be nonspecific for phosphatase activity and hydrolyzed disparate organophosphates.

Novel scheme for synergistic purification of copper mine tailings and orthophosphate.

Copper tailings (CTs) and orthophosphate are major environmental pollutants. CTs cause severe heavy metal pollution, and orthophosphate is one of the primary causes of water body eutrophication. This study aimed to alleviate heavy metal pollution by CTs and the eutrophication of water caused by orthophosphate. To this end, a 50 mg/L orthophosphate was used as a chemically active leaching solution and passed through a CT soil column. The tail water was then collected. Laboratory leaching tests showed that the thermally modified CTs effectively trapped orthophosphate, and the orthophosphate content in the leachate was 0.15 mg/L. After chemical washing, Cu2+, Cd2+, and Zn2+ were tested in the tail water, and the heavy metal ions in the tail water were removed using an advanced treatment technology. After treatment with 20.0 g/L water hyacinth biochar (WHBC), the removal rates (R%) of Cu2+, Cd2+, and Zn2+ were 99.48, 94.94, and 94.84%, respectively. These results demonstrated that this novel scheme for the synergistic purification of CTs and orthophosphate was feasible in the laboratory. This study provides new theoretical guidance and technical support for CT soil heavy metal remediation and water eutrophication treatment.

Structural Behaviour of Green Geopolymer Concrete Beams and Columns Made with Waste Wood Ash a Partial Substitution Binder

On the demand of reducing the global warming due to cement production which is used as main constituent in the production of concrete and minimizing the environmental impact caused by the waste and its disposal methods, this study was aimed. This study looked in to detail insight view on effective utilization of waste wood ash in the production of geopolymer concrete beams and columns to alternate the conventional reinforced concrete elements in construction industry. Waste wood ash is a waste by product produced in the nearby hotel and factories by burning the waste wood collected from timber industries and the ash are thrown in to land which creates a major environmental pollution. Geopolymer is a novel inorganic eco-friendly binding agent derived from alkaline solution that stimulates aluminosilicate source material (such as metakaolin, fly ash and GGBS). In this research, behaviour of beams in deflection, ductility factor, flexural strength and toughness index and columns in load carrying ability, stress strain behaviour and load-deflection behaviours were examined for three types of concretes (30% WWA – 70% Fly ash Geo-polymer concrete, Fly ash Geo-polymer concrete and Reinforced Cement Concrete). The results showed that inclusion of waste wood ash in geopolymer concrete helped in enhancing the load carrying capacity of beam and column by 42% and 28%. Further, the behaviour of structural elements in stiffness, ductility and toughness were also improved with the replacement of waste wood ash.

Estimation of the reference lead (Pb) concentration levels affecting immune cells in the blood of Black-headed Gulls (Chroicocephalus ridibundus, Laridae)

The biological effects of lead (Pb) contamination have been reported in various species. There are no restrictions on the use of Pb products, including bullets, in the areas south of Hokkaido, Japan. Local governments have announced the presence of Pb in the soil sediments of water bodies. Previous studies have confirmed the relationship between blood Pb level (BLL) and immune cells. This study was performed with the aim of clarifying the effect of Pb contamination on immune cells. In total, 170 Black-headed Gulls (<em>Chroicocephalus ridibundus</em>) were captured, including a population in Tokyo Bay between November 2018 and April 2021 and a population in Mikawa Bay between January 2019 and April 2021. Linear regression analysis was performed with the white blood cell count (WBC), proportion of heterophils (Het), proportion of lymphocytes (Lym), ratio of heterophils and lymphocytes (H/L ratio), copy number of CD4 messenger RNA, and copy number of CD8α messenger RNA as the objective variables, and the BLL as the explanatory variable. The group with BLL < 1.0 µg/dL had a significantly lower Het and higher Lym than that with BLL > 3.5 µg/dL (<em>P</em> < 0.05). In addition, the group with BLL < 1.0 µg/dL had a significantly lower H/L ratio than that with BLL > 3.5 µg/dL. CD8α and WBC were higher in the group with BLL ranging from 1.0 to 3.5 µg/dL than in the group with BLL < 1.0 µg/dL. This study suggests that the effect of Pb pollution on the immune cells of Black-headed Gulls is lower than some previous criteria values. It is possible that gulls affected by Pb contamination suffer indirect negative effects on immune function, possibly making them more susceptible to infectious diseases. Pb is a major environmental pollutant, against which measures must be taken.

Research on convection-reaction-diffusion model of contaminants in fracturing flowback fluid in non-equidistant fractures with arbitrary inclination of shale gas development

The large-scale hydraulic fracturing technology used in shale gas development will cause major environmental pollution problems. Therefore, determining the concentration of contaminants in the fracturing flowback fluid to reduce surface water pollution caused by shale gas development is one of the main tasks facing shale gas development. This paper mainly studies the convection, reaction and diffusion process of contaminants in fracturing flowback fluid in non-equidistant fractures with arbitrary inclination. Firstly, based on the convection-reaction-diffusion model of fluid and combined with the fracture morphology, the convection-reaction-diffusion model of contaminants in fracturing flowback fluid in non-equidistant fractures with arbitrary inclination is established. Secondly, in order to solve the established model, an improved fracture equivalent method is proposed, which fully considers all the distributions of the left and right wings of the fractures. Thirdly, the convection-reaction-diffusion model is solved by using coordinate transformation, the Laplace transform method, the characteristic root method, and the Gaver-Stehfest numerical inversion method. Then the concentration of contaminants at the port of the left and right wings of each fracture near the horizontal wellbore in real space is obtained. Finally, taking the chloride ion in the fracturing flowback fluid as an example, the influence of the main controlling factors on its concentration is studied. The results show that the chloride ion concentration increases nonlinearly with the linear increase of backflow velocity and molecular diffusion coefficients, and decreases nonlinearly with the linear increase of rate coefficients and the length of the fracture. This research provides a theoretical basis for the research on the flowback pollution of fracturing flowback fluid. • Convection-reaction-diffusion model of contaminants in flowback fluid in non-isometric fractures is established. • This paper proposes the improved fracture equivalent method. • The model is solved by using coordinate transformation, characteristic root method, Laplace transform and its inversion-. • The methods to solve the model are simple and effective for solving convection-reaction-diffusion model. • By the sensitivity analysis, we know that varies nonlinearly with the linear increase of ς f i l , v f i l , D and L f i l .

THE EFFECT OF OLIVE WASTES FOR POULTRY FEED ON GROWTH PERFORMANCE OF BROILERS: A review

The increasing demand for animal products has increased the demand of feed ingredients around the world. However, the decrease in natural resources, cultivated lands, and resulted in continuous supply of feed ingredients. For this reason, studies on alternative feed ingredients are the main interest of scientists. Olive industry by products are one of the major environmental pollutant and these by-products could be potential alternative feed ingredients for livestock /poultry industry. Studies have reported that the reuse of olive by-products in broiler feeding has an impact on environmental, economic and growth performance. Current review will provide the information that olive industry by-products can be used efficiently in broiler feeding. It will also contribute to the elimination of environmental problems caused by the breakdown of such wastes in the environment. However, maintaining the nutritional value, preservation methods and feed incorporation level in order to include these unconventional feed sources in the diet of farm animals is another problem that needs to be studied. This study will provide the evidence that olive industry by-products not only will increase the growth performance of broilers, but increase the olive industry profit and reduce environmental pollution. Keywords: leaves, olive, pomace, pulp, waste recycling.

SiRNA@superparamagnetic iron oxide nanoparticles attenuate physiological toxicity of DEHP by suppressing autophagy pathway activities in Caenorhabditis elegans

Bis(2-ethylhexyl)ortho-phthalate (DEHP) is a widely used plasticizer in polyvinyl chloride materials. Considering its widespread application, it has become a major environmental pollutant and can cause endocrine, reproductive system, and gastrointestinal disorders. Herein we aimed to elucidate the mechanisms via which DEHP causes cytotoxicity in Caenorhabditis elegans and assess whether siRNA@superparamagnetic iron oxide nanoparticles (SPIONs) can attenuate this effect. On exposing C. elegans to 10 μM DEHP, its physiological functions and gene expression levels were markedly affected. RNA-seq and Kyoto Encyclopedia of Genes and Genomes pathway analyses indicated that DEHP exposure significantly activated the autophagy-animal signal transduction pathway in the somatic cells of C. elegans. Subsequently, the surface of SPIONs was loaded with siRNAs and transfected into C. elegans. Transmission electron microscopy showed that SPIONs could smoothly enter the somatic cells of C. elegans. Further, qPCR showed that the expression levels of autophagy pathway-related genes, namely Atg-2, Epg-9, Atg-18, Bec-1, and Atg-16.2, in the siRNA@SPION intervention group were significantly lower than those in the control group. Biochemical and physiological test results suggested that siRNA@SPION complexes attenuated DEHP-induced physiological toxicity and oxidative stress damage in C. elegans. Collectively, our findings indicated that DEHP markedly affects the physiological activity of C. elegans, induces changes in gene expression levels, and activates the autophagy signal transduction pathway and that siRNA@SPION complexes suppress such toxic effects by silencing the expression of genes involved in the autophagy signal transduction pathway.

Microplastics in soil: Impacts and microbial diversity and degradation

Microplastics (MPs) are plastic particles less than 5 mm in size that have become a major environmental pollutant due to their ubiquitous and persistent nature. Microplastic contamination of the aquatic environment has received the most attention so far, whereas the current understanding of MP prevalence and its impacts in the terrestrial environment is largely limited. The MP contamination of soil can cause bioaccumulation and toxicity in terrestrial animals and plants, which can consequently affect human health. This review is aimed towards combining the available information on the occurrence, sources, and effects of MPs on the different aspects of the terrestrial environment and to highlight the limitations in our knowledge regarding the nature and impacts of MPs in soil. The review also highlights microbial degradation of MPs as an advancing research area, with numerous microorganisms being identified as capable of efficiently degrading this persistent contaminant.

The influence of doping amount on the catalytic oxidation of formaldehyde by Mn-CeO2 mixed oxide catalyst: A combination of DFT and microkinetic study

Formaldehyde (HCHO) is a major environmental pollutant. The Mn-doped CeO2 catalyst has good catalytic performance for the oxidation of HCHO. The catalytic activity can be effectively tuned by changing the amount of metal doping. In this paper, density functional theory combined with micro-kinetic analysis are employed to provide a molecular level understanding to such effects. The CeO2(111) surface with different Mn doping content was used to study the oxidation mechanism of HCHO. Highly dispersed Mn doped ceria was dominant at low content of Mn. While with the increase of Mn doping, Mn begins to accumulate on the CeO2(111) surface. It is not conducive to the breaking of C-H bonds, the generation of oxygen vacancies and the adsorption of active oxygen species. Therefore, the low-content Mn-doped CeO2 catalyst has higher catalytic oxidation activity of HCHO. The present contribution is useful for further optimization of Mn-CeO2 catalysts towards HCHO oxidation.

Kidney transcriptome analysis of rats (Rattus norvegicus) revealed induction of renal injury and damage markers in response to melamine

ObjectivesMelamine is a major environmental indigestible pollutant molecule that represents a pertinent risk to human health on a daily bases. The focus of the current study was the investigation of melamine effects on the rat (Ratus norvegicus) kidney transcriptome for detecting changes in gene expression during the early stages of the kidney damage. MethodsMelamine was administered for 1 month to rats at 60 and 120 mg/kg/day to investigate its impact on the whole transcriptome of rat kidney. Transcriptome developed from mRNA of kidney cells was established using Illumina NovaSeq 6000 System with paired end sequencing of 100 bp with sequencing depth of 60 million reads and sequencing coverage of 6 Gb. ResultsResults indicated the upregulation of 379 and 718 genes in the M60 and the M120 groups consecutively and the downregualtion of 167 and 392 in the M60 and the M120 groups consecutively. Also, melamine administration significantly enriched 2329 GO (Gene Ontology) terms (1890 BP terms, CC 191 terms, 248 MF terms) and 198 KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways. Differentially expressed genes (DEGs) were related to process involved in kidney functions as well as early stages of kidney injury and fibrosis. These included cell–cell adhesion, cell-matrix adhesion, cytoskeleton organization, response to stress, olfactory transduction and perception, and several interesting kidney function markers. The enriched GO terms and KEGG pathways were also related to the DEGs groups. ConclusionsResults of the current study confirm that subchronic sublethal levels of melamine were able to initiate the early stages of kidney injury and fibrosis and introduce some early markers of kidney injury in the early diagnosis of kidney damage.

Chronic exposure to ammonia induces oxidative stress and enhanced glycolysis in lung of piglets.

Ammonia is one of the major environmental pollutants in the pig industry that seriously affects the airway health of pigs. In this study, we aimed to investigate the metabolic profiling changes of piglets' lung tissue after the exposure of 0 ppm (CG), 20 ppm (LG) and 50 ppm (HG) ammonia for 30 days. Compared with the control group, the obvious lung lesions were observed in HG, including interstitial thickening, inflammatory cell infiltration and focal hemorrhage. The significantly increased content of malondialdehyde in HG, combined with the significantly decreased mRNA expression of antioxidase and inflammatory-regulators in exposure groups, implied that ammonia exposure induced oxidative stress and diminished the anti-inflammatory response in lung tissues. Metabolomic analyses of lung tissues revealed 15 significantly altered metabolites among the three groups including multiple amino acids, carbohydrates and lipids. The accumulation of succinic acid, linoleic acid and phosphorylethanolamine and consumption of glucose, quinolinic acid and aspartic acid in ammonia exposure groups, indicated that energy supply from glucose aerobic oxidation was suppressed and the glycolysis and lipolysis were activated in lung tissues induced by chronic ammonia exposure.

Evaluation of oxidative stress, inflammation, apoptosis, oxidative DNA damage and metalloproteinases in the lungs of rats treated with cadmium and carvacrol.

The potential protective properties of carvacrol (CRV), which possesses various biological and pharmacological properties, against lung toxicity caused by cadmium (Cd), a major environmental pollutant, were investigated in the present study. In the study, rats were given 25 or 50mg/kg CRV orally 30min after administrating 25mg/kg cadmium chloride for seven days. Subsequently, the levels of 8-OHdG, MMP-2, and MMP-9, as well as markers of oxidative stress, inflammation, and apoptosis, were analyzed in the lung tissue of the animals. The results revealed that CRV exhibited antioxidant characteristics and raised SOD, CAT, GPx, and CAT levels and decreased the MDA levels induced by Cd. It also suppressed proinflammatory cytokines by lowering the levels of CRV NF-κB and p38 MAPK, thus exerting an anti-inflammatory effect against Cd. It was found that the levels of Bax, Caspase-3, and cytochrome c increased by Cd were decreased by the application of CRV. CRV also showed an anti-apoptotic effect by increasing Bcl-2 levels. The levels of 8-OHdG, MMP2, and MMP9, which increased with Cd administration, were observed to reduce after treatment with CRV. The results indicate that CRV has protective properties against Cd-induced lung toxicity.

A highly sensitive and selective ratiometric sensing platform based on 7-amino-4-methylcoumarin for naked-eye visual fluorescence sensing of Cu2+

Cu2+ is a major environmental pollutant. An efficient measurement for Cu2+ is urgently needed. In this report, we have developed a new sensitive and selective ratiometric sensing platform using 7-amino-4-methylcoumarin (AMC) for detecting Cu2+ in real samples. In the presence of Cu2+, o-phenylenediamine (OPD) could be catalytically oxidized to 2,3-diaminophenazine (DAP), which could react with AMC, leading to quench the fluorescence intensity of AMC at 438 nm. Meanwhile, DAP provided a new emission peak at 557 nm. Based on the efficient overlapped spectrum of AMC and DAP, a ratiometric sensing platform through fluorescence resonance energy transfer (FRET) was carried out. Furthermore, the as-proposed strategy displayed the linear relationship in the wide range from 6 to 250 μM with a low detection limit of 0.059 μM, and the recoveries of the spiked samples in real samples ranged from 86.5% to 110.1%. Moreover, comparing the visual fluorescence colors of the real samples with the standard colorimetric card, we used the as-proposed strategy as a solid-based platform for realizing an efficient semi-quantitative detection of Cu2+ via naked-eye visual fluorescence mode without any complicated instrument and operation. The above results implied that the as-proposed strategy could be used in the practice determination of Cu2+.

Novel strategy in biohydrogen energy production from COVID - 19 plastic waste: A critical review

Usage of plastics in the form of personal protective equipment, medical devices, and common packages has increased alarmingly during these pandemic times. Though they have served as an excellent protection source in minimizing the coronavirus disease (COVID-19) spreading, they have still emerged as major environmental pollutants nowadays. These non-degradable COVID-19 plastic wastes (CPW) were treated through incineration and landfilling process, which may lead to either the release of harmful gases or contaminating the surrounding environment. Further, they can cause numerous health hazards to the human and animal populations. These plastic wastes can be efficiently managed through thermochemical processes like pyrolysis or gasification, which assist in degrading the plastic waste and also effectively convert them into useful energy-yielding products. The pyrolysis process promotes the formation of liquid fuels and chemicals, whereas gasification leads to syngas and hydrogen fuel production. These energy-yielding products can help to compensate for the fossil fuels depletion in the near future. There are many insights explained in terms of the types of reactors and influential factors that can be adopted for the pyrolysis and gasification process, to produce high efficient energy products from the wastes. In addition, advanced technologies including co-gasification and two-stage gasification were also reviewed.

Selective detection of VOCs using microfluidic gas sensor with embedded cylindrical microfeatures coated with graphene oxide

Volatile organic compounds (VOCs) are major environmental pollutants. Exposure to VOCs has been associated with adverse health outcomes. The monitoring of hazardous VOCs is a vital step towards identifying their presence and preventing the risk of acute or chronic exposure and polluting the environment. One of the challenges associated with monitoring VOCs is selectivity of the sensor. Microfluidic gas sensors offer selective and sensitive detection capabilities that have been recently applied for detection of VOCs. In this study, we achieve improved selectivity for detection of a range of VOCs by adding micro- and nanofeatures to the microchannel of microfluidic gas sensors. First, microfeatures are embedded into the microchannel and their geometries are optimized using Taguchi design of experiment method. In the next step the microfeatures embedded microchannel is coated with graphene oxide, to increase the surface to volume ratio by introducing nanofeatures to the surfaces. The nano- and microfeatures are characterized by SEM, XPS, and water contact angle measurement. Finally, the changes in the sensor response are compared to plain microfluidic gas sensor, the results show an average of 64.4% and 120.9% improvement in the selectivity of the sensor with microfeatures and both nano- and microfeatures, respectively

Review on Air Pollution on Health and Its Prevention

Air pollution is the major environmental pollution that contains different types of gases, dust particles, small molecules, etc. Smoke and other hazardous gases, such as carbon, sulfur, and nitrogen oxides, are the primary causes of air pollution. Otherwise, air pollution is the contaminated air that poisonous effect on people's health. Most air pollution is affected by auto-rickshaw drivers. Auto drivers doing very stressful works which have been associated with environmental interaction factors. So the auto drivers are working within the environment, auto drivers are exposed to climate changes and poor road conditions. So the drivers are exposed to air pollution, dust, droplets, job insecurity, noise and vibration, business demands, damage to equipment, an excessive number of stops, schedule-related pressure, among others. Drivers’ social role is also reflected in the responsibility of passengers and pedestrians ‘lives and other vehicles.

Assessment of Auto-rickshaw Drivers Knowledge Regarding the Effects of Air Pollution on Health and Its Prevention

Background: Air pollution is the major environmental pollution that contains different types of gases, dust particles, small molecules, etc. Air pollution is mainly caused by smoke or other harmful gases, such as oxides of carbon, sulfur, and nitrogen. Auto-rickshaw drivers are not only affected by air pollution, they are exposed to climatic changes, and. poor road conditions. They are exposed to air pollution, dust, infected droplets, job insecurity, noise pollution and vibration, business demands, damage to their vehicles, and, schedule-related pressure. Drivers also have the responsibility of their passengers and pedestrians- ‘lives and other vehicles. The objective of the study is to analyze knowledge among auto-rickshaw drivers regarding the health effects of air pollution and its prevention.&#x0D; Methods: An observational research methodology, a cross-sectional research design was used to perform this analysis. Probability purposive sampling technique was used to collect data from auto-rickshaw drivers based on the health effects of air pollution and its prevention utilizing structured questionnaires. The sample attributes have been defined by frequency, percentage, after data collection. The Chi-square test was also used to figure out the correlation between knowledge and specified demographic variables.&#x0D; Results: The findings show that 1.67% of auto-rickshaw drivers had an average level of knowledge score, 38.33% of them were having good and 60 % of them were having an excellent level of knowledge score and none of them were found to have a very poor level of knowledge. The minimum knowledge score was 7 and the maximum knowledge score was 14. Hence it indicates that auto-rickshaw drivers have good knowledge about the effect of air pollution and their prevention.&#x0D; Conclusions: The study shows that the auto-rickshaw drivers having good knowledge about air pollution to the management of respiratory diseases and along with their complications as well as to take the required measures to avoid respiratory complications.

Microplastics pollution from different plastic mulching years accentuate soil microbial nutrient limitations

Microplastics (MPs) are major global environmental pollutants that have been extensively detected in agroecosystems. However, researches on their distribution and fates in farmland as well as their potential impacts on soil ecosystems are limited, especially studies on the influences of MPs on enzymes associated with carbon (C), nitrogen (N), and phosphorus (P) cycling and microbial nutrient limitations characterized by enzymatic stoichiometry are missing. In this study, we investigated the MPs characteristics under different continuous mulching management years (3, 6, 10, 15, and 20a) of tobacco fields in Enshi Prefecture, China, and identified the mechanisms of MPs pollution on soil microbial nutrient limitations. The results showed that the abundance of MPs varied from 647 to 2840 items/kg. Films, fibers and small-sized particles (0–1.0 mm) were the predominant types and size, respectively, and increased significantly with the increase of planting years. A vector analysis of enzyme activity suggested that microbial metabolism was limited both with C and P. The correlation analysis demonstrated that MPs pollution and soil properties were significantly linked to microbial nutrient limitations. Meanwhile, partial least squares path model (PLS-PM) revealed that MPs abundance exacerbated microbial limitation mainly by directly affecting soil microbial properties, followed by soil physical properties and soil nutrients, whereas MPs size and shapes indirectly exacerbated microbial nutrient limitation by significantly influencing MPs abundance. These results demonstrated that contamination of soil with MPs may have deleterious effects on soil key functions related to microbial metabolism, nutrient cycling, etc. Changes in soil properties and functions can damage plant growth and development, which may further affect crop yield and quality. This study provided a new theoretical basis for the response of soil microbial metabolism to MPs pollution and facilitated a better understanding and estimation of the environmental behavior and ecological risk of MPs in agricultural fields.