Major Environmental Pollutant Research Articles

Review of the Researches on China􀆳s Ecological Environment Governance from the Perspective of Political Economics

The issue of ecology and environment is not only a technical and economic issue, but also a political one. The literature on environmental governance from the perspective of political economy can be divided into four categories: the perspective of governance capabilities of local government, the perspective of local government competition, the perspective of “government-enterprise collusion”, and the perspective of power balance. These four types of literature generally show a change from the benevolent government hypothesis to a self-interested government, from a holistic methodology that takes local governments as the unit of analysis to an individualist methodology that takes individual officials as the object of research, a change from a focus on the superficial reasons such as the government's ability to governance and the effectiveness of the policy to deep-seated reasons such as the power structure of the pluralistic subjects of society. This paper argues that ecological environmental protection involves the interests of multiple subjects, but the imbalance in the distribution of power and the pattern of interests among the subjects, and the excessive power of local government to speak and the insufficient ability of the public to participate in society, has led to the distortion of the environmental protection system in its implementation. This is why there local government has been behind all the major environmental pollution incidents in the country in recent years, and why almost all environmental pollution problems are obvious violations of existing laws and regulations, rather than a lack of institutions. The “interest-power-institution” equilibrium perspective provides a powerful theoretical framework for a comprehensive understanding of the prevention and control of ecological damage.

Screening and optimization of Manganese peroxidase (MnP) production by Pseudoduganella violacea (SMB4), a bacterial isolate from Similipal Biosphere Reserve, Odisha and evaluation of Maillard reaction products degradation

The Maillard reaction products (Melanoidin) are major environmental pollutants of the distillery and fermentation industries. Manganese peroxidase (MnP) was found to be an efficient ligninolytic enzyme capable of degrading Maillard products. MnP can convert Mn2 ions in wood and soils to the more reactive Mn2+ ions. The current study aims to isolate MnP producing bacteria from Similipal Biosphere Reserve (SBR), Odisha, and determine its biodegradation ability towards millards products. In total 10 ligninolytic bacterial colonies were isolated from the soil sample of SBR and their MnP activity was screened using phenol red dye as an indicator. The isolate, SMB4 was found to be the most efficient MnP-producing bacterium showing the highest MnP activity of 3.89 U/ml/min in un-optimized conditions. The bacterium was identified as Pseudoduganella violacea based on morphological, biochemical and molecular characterization. MnP activity of SMB4 was optimized using response surface methodology. Under optimized conditions SMB4 showed MnP activity of 6.12 U/ml/min which is 1.57 times from un-optimized condition. The isolate SMB4 was found to show significant decolorization of maillards products up to 83.68 % at temperature 37 °C within 192 h of incubation. The degraded product was analyzed using UV–vis and FTIR analyses. The current investigation suggests that MnP produced by Pseudoduganella violacea may be successfully exploited for bioremediation purposes to degrade Maillard products.

Recent Aptamer-Based Biosensors for Cd2+ Detection.

Cd2+, a major environmental pollutant, is heavily toxic to human health. Many traditional techniques are high-cost and complicated; thus, developing a simple, sensitive, convenient, and cheap monitoring approach is necessary. The aptamer can be obtained from a novel method called SELEX, which is widely used as a DNA biosensor for its easy acquisition and high affinity of the target, especially for heavy metal ions detection, such as Cd2+. In recent years, highly stable Cd2+ aptamer oligonucleotides (CAOs) were observed, and electrochemical, fluorescent, and colorimetric biosensors based on aptamers have been designed to monitor Cd2+. In addition, the monitoring sensitivity of aptamer-based biosensors is improved with signal amplification mechanisms such as hybridization chain reactions and enzyme-free methods. This paper reviews approaches to building biosensors for inspecting Cd2+ by electrochemical, fluorescent, and colorimetric methods. Finally, many practical applications of sensors and their implications for humans and the environment are discussed.

Glycyrrhizin protects against particulate matter-induced lung injury via regulation of endoplasmic reticulum stress and NLRP3 inflammasome-mediated pyroptosis through Nrf2/HO-1/NQO1 signaling pathway

Particulate matter (PM) is a major environmental pollutant that contributes considerably to deaths worldwide. The pathogenesis of PM-induced lung injury (PILI) is far from elucidated and warrants effective intervention. An effective component of licorice, glycyrrhizin (GL), has been the subject of much research due to its anti-inflammatory and anti-oxidative capabilities. Although preventive properties of GL are well-known, the precise mechanism of GL in PILI has not yet been investigated. A mouse model of PILI was used to examine the protective effects of GL in vivo, and a human bronchial epithelial cells (HBECs) model was used in vitro. In order to determine whether GL mitigates PILI, its effects on endoplasmic reticulum (ER) stress, NLRP3 inflammasome-mediated pyroptosis and the oxidative response were examined. According to the findings, GL reduced PILI and activate anti-oxidative Nrf2/HO-1/NQO1 signaling in mice. Notably, the effect of GL on PM-induced ER stress and NLRP3 inflammasome-mediated pyroptosis was significantly attenuated by the Nrf2 inhibitor ML385. The data suggest that via the anti-oxidative Nrf2 signaling, GL may reduce oxidative stress-mediated ER stress and NLRP3 inflammasome-mediated pyroptosis. Therefore, GL may serve as a promising treatment for PILI.

Vitamin D and calcium co-therapy mitigates pre-established cadmium nephropathy by regulating renal calcium homeostatic molecules and improving anti-oxidative and anti-inflammatory activities in rat

BackgroundCadmium (Cd) is a major environmental pollutant and chronic toxicity could induce nephropathy by increasing renal oxidative stress and inflammation. Although vitamin D (VD) and calcium (Ca) prophylactic treatments attenuated Cd-induced cell injury, none of the prior studies measure their renoprotective effects against pre-established Cd-nephropathy. AimsTo measure the alleviating effects of VD and/or Ca single and dual therapies against pre-established nephrotoxicity induced by chronic Cd toxicity prior to treatment initiation. MethodsForty male adult rats were allocated into: negative controls (NC), positive controls (PC), Ca, VD and VC groups. The study lasted for eight weeks and all animals, except the NC, received CdCl2 in drinking water (44 mg/L) throughout the study. Ca (100 mg/kg) and/or VD (350 IU/kg) were given (five times/week) during the last four weeks to the designated groups. Subsequently, the expression of transforming growth factor-β (TGF-β1), inducible nitric oxide synthase (iNOS), neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), VD synthesising (Cyp27b1) and catabolizing (Cyp24a1) enzymes with VD receptor (VDR) and binding protein (VDBP) was measured in renal tissues. Similarly, renal expression of Ca voltage-dependent channels (CaV1.1/CaV3.1), store-operated channels (RyR1/ITPR1), and binding proteins (CAM/CAMKIIA/S100A1/S100B) were measured. Serum markers of renal function alongside several markers of oxidative stress (MDA/H2O2/GSH/GPx/CAT) and inflammation (IL-6/TNF-α/IL-10) together with renal cell apoptosis and expression of caspase-3 were also measured. ResultsThe PC group exhibited hypovitaminosis D, hypocalcaemia, hypercalciuria, proteinuria, reduced creatinine clearance, and increased renal apoptosis/necrosis with higher caspase-3 expression. Markers of renal tissue damage (TGF-β1/iNOS/NGAL/KIM-1), oxidative stress (MDA/H2O2), and inflammation (TNF-α/IL-1β/IL-6) increased, whilst the antioxidants (GSH/GPx/CAT) and IL-10 decreased, in the PC group. The PC renal tissues also showed abnormal expression of Cyp27b1, Cyp24a1, VDR, and VDBP, alongside Ca-membranous (CaV1.1/CaV3.1) and store-operated channels (RyR1/ITPR1) and cytosolic Ca-binding proteins (CAM/CAMKIIA/S100A1/S100B). Although VD was superior to Ca monotherapy, their combination revealed the best mitigation effects by attenuating serum and renal tissue Cd concentrations, inflammation and oxidative stress, alongside modulating the expression of VD/Ca-molecules. ConclusionsThis study is the first to show improved alleviations against Cd-nephropathy by co-supplementing VD and Ca, possibly by better regulation of Ca-dependent anti-oxidative and anti-inflammatory actions.

Effect of additives on the compressive strength and denitrification performance of fly ash catalysts

AbstractFly ash is a massive industrial waste. Owing to the abundance of oxides, such as SiO2 and Al2O3, fly ash is considered a high value material. In this study, we assessed its application in the industrial deoxidation of nitrogen oxides, a major environmental pollutant, using the selective catalytic reduction technology. Fly ash was used as the main raw material and bentonite was used as an auxiliary material in the catalyst. Silica sol, starch, and glycerol were added to improve the compressive strength and denitrification performance of the catalyst. The use of silica sol as a binder improved the compressive strength of the catalyst due to the production of Si–O–Si. In addition, the availability of acidic functional groups could improve the denitrification performance of the catalyst. The optimal dosages of the additives were as follows: 6% silica sol, 6% starch, and 5% glycerol. Under these conditions, the catalyst formation was the easiest, the cracks were the least, the compressive strength of the catalyst reached 1434 kPa, and the denitrification performance improved. The findings presented here are relevant for the development of an economical and practicable solution for tackling environmental pollution caused by nitrogen oxides.

Elevational Gradient Effects on Microbial Distribution in Crude Oil Polluted Sites

Crude oil is a major environmental pollutant in the Niger Delta region of Nigeria due to heightened operations of the petroleum industry in this location. This comparative study of two different petroleum hydrocarbon-polluted soils from the Bodo and Tombia communities in Rivers State was carried out to determine microbial abundance (distribution) in relation to the depth and soil texture of the polluted sites. Soil samples were collected at 15 cm and 30 cm from each site. Baseline physicochemical parameters and microbial counts were determined using standard methods. Hydrocarbon utilizing bacteria were screened with 2,6-dichlorophenol indophenol (DCPIP) for crude oil degradation efficiency. The average total petroleum hydrocarbons (TPH) collected from the areas values are higher than the intervention value of 5000 mg/kg as stipulated by the Department of Petroleum Resources (DPR) in the Environmental Guidelines and Standards for the Petroleum Industry in Nigeria (EGASPIN). Microbial distribution patterns were not significantly different (p=0.08) between the topsoil and subsoil in the sites investigated. There was no significant variance in the relationship between soil texture and microorganism distribution (p=0.998). An interaction of the effects between the two independent variables produced an insignificant variance (p=0.411). Average viable culturable heterotrophic and hydrocarbon utilizing microbial counts for the sites varied considerably between 105 and 106 colony forming units per gram of soil (cfu/g) at both depths. A consortium of Pseudomonas spp., Proteus spp., Sphingobacterium spp., and Bacillus spp. isolated from the sites efficiently degraded crude oil, showing a 100% decolourization of DCPIP in Bushnell-Haas-crude oil broth. This study demonstrated that soil texture and depth affect microbial diversity and their function in crude oil contaminated sites.

A framework for environmental production of textile dyeing process using novel exhaustion-rate meter and multi-layer perceptron-based prediction model

In textile industries, a lot of wastewater are discharged which are one of the major environmental pollution problems, because they release undesirable dye effluents. Owing to re-dyeing procedures performed to meet customized color specifications, environmental pollution is a serious problem because of the emission of large volumes of wastewater. To solve the environmental problems caused by re-dyeing, the right-first-time (RFT) %, which is the rate at which the target quality is obtained with just one dyeing, must be increased by considering the dyeing conditions that affect product quality. Here, this study suggests a framework for cleaner production of textile dyeing process using novel exhaustion-rate meter (NERM) and multi-layer perceptron-based prediction model to solve the environmental problems caused by re-dyeing procedure by controlling the exhaustion-rate outliers. The proposed NERM measures the exhaustion-rate based on absorbance of the dyeing solution and is composed of measuring and analysis section. The dyeing solution absorbance is metered in the measuring component through a detector, which performs high-resolution measurement (0.3–1.5 nm full width at half maximum) via a 25-μm slit in the 200–1100-nm wavelength range; the absorbance is then converted to the exhaustion-rate based on Beer's law in the analysis section. Using the NERM, an exhaustion rate dataset according to the Na2SO4 and Na2CO3 consumption is acquired and a surrogate model that augments the exhaustion rate data is developed. The MLP-based prediction model is then developed using the augmented data to control the real-time exhaustion-rate outliers. As a results, the model performance as regards Na2SO4 and Na2CO3 prediction is indicated by R2 values of approximately 0.985 and 0.998, respectively, and root mean squared errors (RMSE) of approximately 1.477 and 1.000, respectively. In addition, the effectiveness of the proposed framework is demonstrated through application to several scenarios in which the real-time exhaustion rate outliers are detected.

Quantitative Detection of Microplastics in Water through Fluorescence Signal Analysis

Microplastics (MPs) have recently been acknowledged as a new major and ubiquitous environmental pollutant with still unclear, yet potentially high, risks for different ecosystems and human health. Nevertheless, quantitative identification protocols rely on long and subjective visual counting necessarily performed on microscopes by well-trained operators. In this study, an automatic, fast, portable, and inexpensive method for the quantitative detection of MPs in water is proposed. The system is based on the typical optical setup of a fluorescence confocal microscope specifically adapted to automatically count dye-stained MPs in flowing liquids using a low-power laser beam. The fluorescence pulses emitted by flowing MPs are revealed and processed by a specific software using a pattern recognition algorithm to discriminate and count real fluorescence pulses out of noise fluctuations. The system was calibrated with commercial orange fluorescent 10 µm and 1 µm polystyrene microspheres, and remarkable agreement with theoretical predictions was obtained regarding different parameters. Tests were also performed with laboratory-prepared MPs dispersed in different types of real water samples. In this case, the agreement with theory was slightly worse and differences found in the quantitative results require further investigation. However, the present study demonstrated the proof of concept of a method for quick automated MP counting in water.

Polyethylene terephthalate (PET) biodegradation by Pleurotus ostreatus and Pleurotus pulmonarius

The essential properties of polyethylene terephthalate (PET), such as chemical inertness and durability that make it a suitable material for the packaging of mineral and soft drinks, have led to it becoming a major environmental pollutant and a threat to the planet. Ecologically friendly solutions such as bioremediation are now being advocated for by scientists. This paper, therefore, seeks to explore the potential capacity of Pleurotus ostreatus and Pleurotus pulmonarius in biodegrading PET plastic on two different substrates (soil and rice straw). The substrates were combined with 5% and 10% plastic before inoculation with Pleurotus ostreatus and Pleurotus pulmonarius and then left to incubate for 2months. Biodegradation, monitored by FT-IR pointed to the formation of new peaks in the incubated plastics after 30 and 60days unlike in the control. Changes in band intensity and shifts in the wavenumbers caused by stretching of functional groups, C-H, O-H and N-H in the band region of 2898cm-1 to 3756cm-1 are confirmed indicators of successful breakdown caused by contact with P. ostreatus and P. pulmonarius. The FT-IR analysis also gave an indication of N-H stretching at 3338.04cm-1 and 3228.62cm-1 for PET flakes incubated with Pleurotus sp. Furthermore, degradation products like hydrocarbons, carboxylic acids, alcohols, esters, and ketones were also detected in the GC-MS analysis of the decomposed PET plastic after 30 and 60days. These compounds are formed due to chain scission caused by the fungal species. There was a discoloration of the PET flakes caused by an increase in carboxyl-terminated species as a result of enzymes secreted by the fungi in the process of biodegradation.

Bacterial benz(a)anthracene catabolic networks in contaminated soils and their modulation by other co-occurring HMW-PAHs

Polycyclic aromatic hydrocarbons (PAHs) are major environmental pollutants in a number of point source contaminated sites, where they are found embedded in complex mixtures containing different polyaromatic compounds. The application of bioremediation technologies is often constrained by unpredictable end-point concentrations enriched in recalcitrant high molecular weight (HMW)-PAHs. The aim of this study was to elucidate the microbial populations and potential interactions involved in the biodegradation of benz(a)anthracene (BaA) in PAH-contaminated soils. The combination of DNA stable isotope probing (DNA-SIP) and shotgun metagenomics of 13C-labeled DNA identified a member of the recently described genus Immundisolibacter as the key BaA-degrading population. Analysis of the corresponding metagenome assembled genome (MAG) revealed a highly conserved and unique genetic organization in this genus, including novel aromatic ring-hydroxylating dioxygenases (RHD). The influence of other HMW-PAHs on BaA degradation was ascertained in soil microcosms spiked with BaA and fluoranthene (FT), pyrene (PY) or chrysene (CHY) in binary mixtures. The co-occurrence of PAHs resulted in a significant delay in the removal of PAHs that were more resistant to biodegradation, and this delay was associated with relevant microbial interactions. Members of Immundisolibacter, associated with the biodegradation of BaA and CHY, were outcompeted by Sphingobium and Mycobacterium, triggered by the presence of FT and PY, respectively. Our findings highlight that interacting microbial populations modulate the fate of PAHs during the biodegradation of contaminant mixtures in soils.

Pinostrobin alleviates testicular and spermatological damage induced by polystyrene microplastics in adult albino rats

BackgroundPolystyrene microplastics (PS-MPs) have become major environmental pollutants that adversely effects multiple organs specifically testicles. Pinostrobin (PN) is an important flavonoid which, shows several pharmacological potentials. PurposeThe current study was designed to elucidate the mitigative effects of PN against PS-MPs induced testicular toxicities in rats. Methods48 male albino rats were randomly distributed into 4 groups, control, PS-MPs group (0.01 mg/kg), PS-MPs + PN group (0.01 mg/kg of PS-MPs; 40 mg/kg of PN) and PN group (40 mg/kg). ResultsPS-MPs intoxication substantially lessened the activities of glutathione peroxidase (GPx), glutathione reductase (GSR), superoxide dismutase (SOD) along with catalase (CAT) while, raised the level of malondialdehyde (MDA) as well as reactive oxygen species (ROS). Additionally, PS-MPs reduced luteinizing hormone (LH), plasma testosterone, follicle-stimulating hormone (FSH) concentration, sperm motility, sperm count, expression of steroidogenic enzymes and Bcl-2 (anti-apoptotic protein) along with the count of spermatogenic cells. While, dead sperm count, sperm abnormalities (tail, neck and head), Bax and caspase-3 (apoptotic proteins) expression along with histopathological anomalies were elevated. Moreover, PS-MPs exposure increased the level of inflammatory markers. However, PN treatment considerably decreased oxidative stress (OS) by reducing ROS as well as increased sperm motility and alleviated all the damages induced by the PS-MPs. ConclusionTherefore, it is concluded that PN may prove a potential therapeutic candidate to restore all the PS-MPs-induced testicular toxicities.

Industrial solutions for developing low-carbon technologies and achieving carbon neutrality

Aim.The presented study aims to analyze Russian and international experience in the development of measures aimed at reducing the negative impact of climate change and adapting to it; to examine the impact of certain regulatory mechanisms on the business of domestic manufacturing companies.Tasks.The authors investigate the experience of several Russian companies (through the example of ferrous metallurgy and the pulp and paper industry) in the introduction of innovative decarbonization technologies; assess the prospects for their use to achieve decarbonization.Methods.This study analyzes Russian and foreign scientific literature, information from open sources, analytical materials and statistics of international organizations. The subject of the study is the approaches to solving the problem of decarbonization and achieving carbon neutrality.Results.The ways to achieve carbon neutrality in ferrous metallurgy and the pulp and paper industry — the two industries that are major environmental pollutants — are considered in the context of measures aimed at combating the global processes of climate change and Russia’s strategy of socio-economic development with low greenhouse gas emissions until 2050. The prospects of an inertial way of achieving decarbonization and innovative options for the strategic development of low-carbon technologies are described. The prospects of a wider introduction of direct recovery technology in ferrous metallurgy are shown. In the pulp and paper industry, the possibilities of developing technologies for the production of nanocellulose based on the use of industrial waste are identified.Conclusions.From the perspective of responding to climate challenges and achieving the optimal economic effect in ferrous metallurgy, the most strategically justified choice seems to be in favor of an innovative way of structural sectoral transformations aimed towards decarbonization and achieving carbon neutrality by reducing the carbon intensity of production through methods of carbon dioxide capture, use, and storage, and direct reduction of iron based on hydrogen. This conclusion corresponds to the strategy for the development of metallurgy adopted in 2022, which orients the industry toward the development and implementation of innovative lowcarbon technologies. In the pulp and paper industry, it seems promising to conduct further research to obtain innovative technologies for the production of nanocellulose.

Ecotoxicity of soil Pb pollution reflected by soil β-glucosidase: Comparison of extracellular and intracellular enzyme pool

Lead (Pb) is a major environmental pollutant that threatens the soil environment and human health. Monitoring and assessing Pb toxicity on soil health are of paramount importance to the public. To use soil enzymes as biological indicators of Pb contamination, herein, the responses of soil β-glucosidase (BG) in different pools of soil (total, intracellular and extracellular enzyme) to Pb contamination were investigated. The results indicated that the intra-BG (intracellular BG) and extra-BG (extracellular BG) responded differently to Pb contamination. While the addition of Pb caused a significant inhibition of the intra-BG activities, the extra-BG activities were only slightly inhibited. Pb showed a non-competitive inhibition to extra-BG, while both non-competitive and uncompetitive inhibition were observed for intra-BG in the tested soils. The dose-response modeling was used to calculate ecological dose ED10, which represents the concentration of Pb pollutant that causes a 10 % reduction in Vmax, to express the ecological consequences of Pb contamination. A positive correlation was found between ecological dose ED10 values of intra-BG and soil total nitrogen (p < 0.05), which suggests soil properties may influence Pb toxicity to soil BG. Based on the differences in ED10 and inhibition rate among different enzyme pools, this study suggests that the intra-BG is more sensitive for Pb contamination assessment. From this, we propose that intra-BG should be considered when evaluating Pb contamination using soil enzymes as indicators.

Remediation of Methylene Blue Dye from Wastewater by Using Zinc Oxide Nanoparticles Loaded on Nanoclay

Dyes are one of the major environmental pollutants throughout the world, leading to pollution and numerous diseases. Though several techniques have been applied for the remediation of dyes, most of them are ineffective. The authors developed a halloysite clay/zinc oxide nanocomposite (HC/ZnONC) via a chemical route in the present study. The nanocomposite and its constituents, i.e., raw halloysite clay (HC) and zinc oxide nanoparticles (ZnONPs) (synthesized using the same chemical method) were analyzed for their detailed properties by sophisticated instruments. The field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) analysis showed spherical-shaped ZnONPs with an average size of 54.9 nm and tube-like shapes of HC with a diameter ranging from 40–200 nm and a length at the micron scale, while the nanocomposite had incorporated ZnONPs in their tube-like structures. Ultraviolet-Diffuse Reflectance Spectroscopic (UV-DRS) study revealed the photocatalytic ability of the nanocomposite with a band of 3.08 eV. A high surface area of 60.25 m2/g and the microporous and mesoporous nature of the nanocomposite were confirmed by the Brunauer–Emmet–Teller (BET) surface area analyzer. Finally, the developed nanocomposite was used for the remediation of methylene blue from the aqueous solutions, and the efficiency of removal varied from 90 to 97%.

Adsorption of Methylene Blue by Bentonite Supported Nano Zero Valent Iron (B-nZVI)

Dyes used in textiles, foods, cosmetics, and chemicals have become a major environmental pollution issue around the world. To address this issue, a number of technologies have been created to remove these pollutants from the environment. Due to their superior properties at nanoscale, numerous nanomaterials have been applied to remove dyes from polluted waters. This research presents the findings of the development of bentonite nano zero-valent iron (B-nZVI) for the treatment of synthetic cationic dyes. This study has three objectives: (i) to produce bentonite nano zero-valence iron (B-nZVI), (ii) to characterize its adsorbents (B-nZVI), (iii) to characterize its adsorption capacity. Four main tests were used for this purpose: (i) a physical test (Brunauer–Emmett–Teller (BET) surface area), (ii) a chemical test (cation exchange capacity (CEC) and X-ray fluorescence (XRF)), (iii) morphology (field emission scanning electron microscopy (FESEM) and (iv) mineralogy (Fourier transform infrared spectroscopy (FTIR). The five factors for the batch equilibrium test are adsorbent dose, concentration, kinetic, pH, and temperature. The batch test showed that the optimum dose for all adsorbents is 0.5 g. For the concentration factor, B-nZVI exhibits larger adsorption capacity (KL = 30,314.0536 L/g; R2 = 1) compared to bentonite (Kd = 0.0219 L/g; R2 = 0.8892). The kinetic factor showed that the adsorption capacity by pseudo-second-order model was the best for both adsorbents (qe = 1.2038 mg/g, R2 = 0.9993 for bentonite and qe = 6.9979 mg/g, R2 = 1 for B-nZVI). For B-nZVI, the interparticle diffusion model (Kf = 0.8645 m2 g−1 min L−1; R2 = 0.9) and intraparticle diffusion model (Kd = 2.3829 m2 g−1 min L−1; R2 = 0.9189) showed a good correlation with the adsorption data, while bentonite showed a lower correlation with the interparticle diffusion model (Kf = 0.0002 m2 g−1 min L−1; R2 = 0.6253) and intraparticle diffusion model (Kd = 0.2886 m2 g−1 min L−1; R2 = 0.6026), respectively. The pH factor showed that the adsorption capacity of bentonite (qe = 0.5674 mg/g) and B-nZVI (qe = 5.3284 mg/g) was highest in acidic conditions (pH 2). As for the temperature factor, there was no significant effect on bentonite and B-nZVI. Therefore, tests can be conducted at room temperature, saving energy. It was also concluded that B-nZVI is the best material for removing MB compared to bentonite and can be considered for the treatment materials of contaminated water.

Combinatorial Structural Engineering of Multichannel Hierarchical Hollow Microspheres Assembled from Centripetal Fe/C Nanosheets to Achieve Effective Integration of Sound Absorption and Microwave Absorption.

Electromagnetic radiation and noise pollution are two of the four major environmental pollution sources. Although various materials with excellent microwave absorption performances or sound absorption properties have been manufactured, it is still a great challenge to design materials with both microwave absorption and sound absorption abilities due to different energy consumption mechanisms. Herein, a combination strategy based on structural engineering was proposed to develop bi-functional hierarchical Fe/C hollow microspheres composed of centripetal Fe/C nanosheets. Both of the interconnected channels created by multiple gaps among the adjacent Fe/C nanosheets and the hollow structure have positive effects on the absorbing performances by promoting the penetration of microwaves and acoustic waves and prolonging action time between microwave energy and acoustic energy with materials. In addition, a polymer-protection strategy and a high-temperature reduction process were applied to keep this unique morphology and further improve the performances of the composite. As a result, the optimized hierarchical Fe/C-500 hollow composite exhibits a wide effective absorption bandwidth of 7.52 GHz (10.48-18.00 GHz) at only 1.75 mm. Furthermore, the Fe/C-500 composite can effectively absorb sound wave in the frequency of 1209-3307 Hz, basically including part of the low frequency range (<2000 Hz) and most of the medium frequency range (2000-3500 Hz), and has 90% absorption of sound at 1721-1962 Hz. This work puts new insight into the engineering and development of microwave absorption-sound absorption-integrated functional materials with promising applications.

Acute and Chronic Effects of Crude Oil Water-Accommodated Fractions on the Early Life Stages of Marine Medaka (Oryzias melastigma, McClelland, 1839)

Oil spill is a major marine environmental pollution issue. Research regarding the long-term effects of oil spills on the early life stage of marine fish is still limited. In this study, the potential adverse impact of crude oil from one oil spill accident which occurred in the Bohai Sea on the early life stages of marine medaka (Oryzias melastigma, McClelland, 1839) was evaluated. A 96-h acute test (larvae) and a 21-d chronic test (embryo-larvae) of water-accommodated fractions (WAFs) from crude oil were conducted, respectively. The results of the acute test showed that only the highest concentration of WAFs (100.00%) significantly affected the mortality of larvae (p < 0.01) and that the 96 h-LC50 was 68.92% (4.11 mg·L-1 expressed as total petroleum hydrocarbons (TPHs)). Larval heart demonstrated histopathological alterations in all WAF-exposed groups. The chronic test results showed that, except for larval mortality, the total hatching success (%)/hatching time of embryos in WAF treatments was not significantly different from those of the control group (p > 0.05), and no malformation was found in surviving larvae after 21 d of exposure. Nevertheless, the exposed embryos and larvae in the highest concentration of WAFs (60.00%) demonstrated significantly reduced heart rate (p < 0.05) and increased mortality (p < 0.01), respectively. Overall, our results indicated that both acute and chronic WAF exposures had adverse impacts on the survival of marine medaka. In the early life stages, the heart of the marine medaka was the most sensitive organ which showed both structural alteration and cardiac dysfunction.

Investigating the differences in metabolism, and the unfolded protein and apoptosis gene responses in two strains of the Pacific white shrimp, Penaeus vannamei Boone, 1931 (Decapoda, Penaeoidea) under ammonia stress

Abstract Ammonia is one of the major environmental pollutants in the aquatic system and poses a great threat to shrimp. In this study, we compared the differences in metabolic enzymes and the mRNA expression of unfolded protein response (UPR)-related genes between the ammonia-resistant (LV-AT) and ammonia-sensitive (LV-AS) strains of Penaeus vannamei, aiming to investigate the different tolerance mechanisms of the two extreme strains underlying ammonia stress. The results showed that elevated ammonia concentrations mainly increased glutamine synthetase (GS) content while inhibiting transglutaminase (TG) content in the muscle of both strains and the contents were significantly higher in LV-AT than in LV-AS after 48 h of ammonia stress (). As a protective or adaptive strategy, the expression of the UPR related genes, including activating transcription factors ATF6, ATF4, and the spliced form of X box binding protein 1 (XBP1) were, respectively, either significantly induced, or inhibited () after ammonia stress. The mRNA expressions of the GRP78 (Bip) gene and the apoptosis gene (caspase 3) are then activated. In hepatopancreas and gills, the associated gene expressions gradually increase in LV-AT, while several related genes in LV-AS were first induced and then gradually inhibited. The expressions of key genes (GRP78, ATF6, XBP1 and ATF4) were significantly higher in LV-AT than that in LV-AS after 48 h of ammonia stress (). These results indicate that some enzymes involved in ammonia metabolism and UPR protection genes tended to be highly expressed in LV-AT. Hence, we speculate that LV-AT has a higher ammonia excretion capacity and a more effective adaptive mechanism after ammonia stress. The experimental results will help to further understand the stress response of P. vannamei to ammonia and provide a new perspective for the underlying molecular mechanism of the ammonia adaptation strategy of at least some strains of P. vannamei.

Development of a rapid and efficient analytical method for trace lead determination: Manganese dioxide nanoflower based dispersive solid-phase extraction

Lead (Pb) is a heavy metal that is highly toxic and a major environmental pollutant. Anthropogenic activities are the main sources of Pb release into the air, water and food, from which humans and other organisms become exposed. In this study, a suitable, rapid, and environmental friendly dispersive solid phase extraction procedure based on manganese dioxide nanoflower (MnO 2 NF-DSPE) was developed for the effective enrichment of Pb coupled with flame atomic absorption spectrometry (FAAS). Under the optimal experimental conditions, limit of detection (LOD), quantification (LOQ) values and enhancement in detection power (EDP) obtained for the MnO 2 NFs-DSPE-FAAS system were calculated as 6.1 µg/L, 20.3 µg/L and 44, respectively. Three different ginger tea samples were used in recovery studies to investigate the applicability/accuracy of the proposed method. Matrix matching calibration strategy was performed in recovery studies and percentage recoveries were calculated between 106 and 122% with low standard deviation values. • Trace level lead was preconcentrated by DSPE prior to FAAS measurement. • MnO 2 nanoflowers were used as adsorbent in the extraction procedure. • LOD and LOQ for ginger tea matrix were 6.09 µg/L and 20.29 µg/L, respectively. • The detection limit for conventional FAAS system was improved by about 43.7 folds. • Recovery results for the prepared ginger tea were found in the range of 106.1–121.5%.