Emeishan large igneous province (ELIP),one of the largest continental volcanic provinces worldwide (e.g.,Karoo),is extensively distributed along the western margin of the Yangtze Block.Even though the consensus that t...Emeishan large igneous province (ELIP),one of the largest continental volcanic provinces worldwide (e.g.,Karoo),is extensively distributed along the western margin of the Yangtze Block.Even though the consensus that the ELIP is of a plume-related origin has been reached for decades,the role of crustal contamination in the petrogenesis of these basalts is still debatable so far.This paper firstly reports the Ba isotopic compositions of the continental flood basalts from the Lijiang,Miyi and Emeishan regions to discuss the genesis of basalts from the ELIP.According to their TiO_(2) contents and Ti/Y ratios,these basalts are divided into two groups,the low-Ti basalts from Lijiang and the high-Ti basalts from Miyi and Emeishan.The Ba isotopic compositions show that the low-Ti basalts have the δ^(138/134)Ba values from-0.33‰to+0.23‰with an average of-0.02‰±0.40‰,and the high-Ti basalts from -0.38‰to+0.38‰with an average of 0.038‰±0.36‰,all of which show a wider range of Ba isotopes relative to that of the primitive mantle (PM).This is unlikely to be explained by partial melting,fractional crystallization or even chemical weathering owing to little Ba isotopic fractionation during these processes.In contrast,variable extents of crustal contamination into the basaltic magmas more likely resulted in such isotopic diversity.The ratios of incompatible elements (e.g.,Nb/U,La/Nb,and Nb/Y) further suggest that the low-Ti basalts experienced higher degrees of crustal contaminations than those high-Ti basalts,which is well consistent with their spatial distributions.In general,the basaltic magmas in the ELIP were probably contaminated by different degrees of crustal materials during their upwelling to the surface.展开更多
The present study aimed to investigate the microbial populations such a bacteria and fungi contamination present in the herbal medicinal preparations (Lepidium sativum, Nigella sativa, Cuminum cyminum, Foeniculum vulg...The present study aimed to investigate the microbial populations such a bacteria and fungi contamination present in the herbal medicinal preparations (Lepidium sativum, Nigella sativa, Cuminum cyminum, Foeniculum vulgare, Pimpinella anisum, Trigoneela foenum-graecum, Cinnamomum verum, peel coffee, Alchemilla valgaris, Vitex agnus-castus) commonly available in different parts of Riyadh, Saudi Arabia. To determine the contamination of the herbal products, experiments such as total aerobic bacterial plate counts were evaluated by various plating techniques. The isolation and identification of fungi were done using czapek dox agar and potato dextrose agar. The results showed that a total of herbal remedies were contaminated with bacteria and fungi (100%). Among the contaminated products, peel of coffee and Vitex angnus-castus were noted more contamination than the other herbal medicinal plants. The results confirmed that the traditionally prepared herbal medications in Riyadh city are likely to be contaminated with a wide variety of potentially pathogenic bacteria and fungi. Therefore, before consumption, the quality assurance of these products should be thoroughly enforced and monitored in the production and distribution of herbal preparations. In conclusion, the present study gives proper evidence that the consumed herbal products contain different levels of pathogenic microbes.展开更多
One of the methods used in practice for the purification of wastewater from vegetable-processing enterprises is biological method of aerobic purification. With the aim to increase air-tank capacity used in traditional...One of the methods used in practice for the purification of wastewater from vegetable-processing enterprises is biological method of aerobic purification. With the aim to increase air-tank capacity used in traditional systems of biochemical purification of wastewater, different ways effecting to the process of vital activity of microorganisms of active sludge are applied. On the one hand, using the compositions of different salts and complex organic biogenous supplements prevents from the accumulation of some anions in the amounts exceeding the limited concentration, on the other hand- allows different groups of microorganisms to choose biogenous elements, which they assimilate easily and fully. It is known, that compounds of silicon and germanium can cause stimulating effects [1] to the organisms of active sludge. The goal of present studies is the intensification of biological processes of oxidation of organic contamination in wastewater by new bio-degradable chemical compounds or compositions on their basis, and by bio-sorbents.展开更多
The presence of microscopic spores in the air affects the quality of air inhaled by animals including humans.Microbial contamination of air impacts the well-being of occupants of an indoor environment,sometimes with d...The presence of microscopic spores in the air affects the quality of air inhaled by animals including humans.Microbial contamination of air impacts the well-being of occupants of an indoor environment,sometimes with dire consequences.The study investigated fungal contaminations of indoor and outdoor air of the Hospital,Library and Senior Common Room(SCR)of the University of Cape Coast,Ghana.Indoor and outdoor air was sampled using the Koch’s sedimentation method.Colony forming units per cubic meter of air(cfu/m^(3))were determined with the Omeliansky formula.The isolated fungi were identified based on morphological and growth characteristics.For indoor air,the least colony counts were recorded in the SCR for both morning and afternoon samples,whilst the Hospital air had the highest colony counts.For outdoor air,the colony counts were lower in SCR and the Library for both morning and afternoon samples compared to the Hospital.The results further indicated that indoor concentrations of fungi,for morning and afternoon,ranged between 4.0x10^(4) and 2.1x10^(5) cfu/m^(3),whereas outdoor concentrations of fungi ranged between 1.1x105 and 3.0x10^(5) cfu/m^(3),revealing an overall higher levels of contamination of outdoor air than indoor air at all the three buildings.Consequently,estimated indoor/outdoor(I/O)concentration ratios of fungi revealed an exogenous source of indoor contaminations at all the three buildings sampled.Fungi isolated from indoor and outdoor air were of the genera Aspergillus,Curvularia,Cylindrocarpon,Fusarium,Mucor,Neurospora,Penicillium and Rhodotorula.We conclude that indoor and outdoor air of the buildings sampled were contaminated with airborne fungi;however,based on estimated I/O ratios,the indoor ambient conditions of the buildings were good.The implication of findings of this study is that the presence of airborne fungal contaminants of indoor and outdoor workplace environment may pose serious occupational health consequences,hence low productivity.展开更多
To assess contamination levels,14 samples were taken from mining sites in the Ngoura gold mining area,to determine the possible ecological hazards of heavy metals(Al,Mn,As,Ba,V,Cr,Ag,Pb,Hg,Y,Th and U).Physico-chemical...To assess contamination levels,14 samples were taken from mining sites in the Ngoura gold mining area,to determine the possible ecological hazards of heavy metals(Al,Mn,As,Ba,V,Cr,Ag,Pb,Hg,Y,Th and U).Physico-chemical parameters(pH,OM,CEC,Available P,and EC)were analysed.Using Induc-tively Coupled Plasma Mass Spectrometry(ICP-MS),heavy metals were iden-tified.The contaminations were estimated using the following methods:en-richment factor(EF),contamination factor(CF),mean contamination index(Im),pollution load index(PLI),geo-accumulation index(I-Geo),and ecolog-ical risk index(Ri).Findings indicated that mining materials exhibit acidic to highly alkaline pH(5.2 to 9.8),are non-saline(EC<250µS/cm),with low to very high OM(1.20 to 6.51),moderate to very high CEC(14.11 to 45 meq/100g),and very low to medium available phosphorus(7 to 34.34 mg/kg).Heavy metal analysis revealed concentrations(mg/kg)exceeding UCC values:soils near mines:Hg(24.81),Pb(18.99),Th(8.46)mining wastes:Y(97.66),Hg(26.96),Pb(25.85),Th(169.96),U(9.8)residues:Hg(19.49),Pb(30.25),Th(21.12),U(16.5)sediments:Ba(682.75),Y(65.75),Hg(4.2),Pb(26.93),Th(236.65),U(16.15).Contamination indices(EF,I-Geo,CF,Im,PLI)revealed contamina-tion by Hg,Y,Pb,Th,and U,with extreme enrichment of Hg across all mate-rials.I-Geo indicated extreme Hg contamination,while Im confirmed contam-ination in most samples.Hg posed a very high ecological risk,making it the principal contaminant in the Ngoura mining area.Phytoremediation can help to reduce the contaminations in this study area.展开更多
Petroleum leakage is a major groundwater contamination source,with chemical composition of water soluble fractions(WSFs)from diverse oil sources significantly impacting groundwater quality and source identification.Th...Petroleum leakage is a major groundwater contamination source,with chemical composition of water soluble fractions(WSFs)from diverse oil sources significantly impacting groundwater quality and source identification.The aim of this study was to assess impact of 15 diverse oils on groundwater quality and environmental forensics based on oil-water equilibrium experiments.Our results indicate that contamination of groundwater by gasoline and naphtha is primarily attributed to volatile hydrocarbons,while pollution from diesel,kerosene,and crude oil is predominantly from non-hydrocarbons.Rapid determination of the extent of non-hydrocarbon pollution in WSFs was achieved through a new quantitative index.Gasoline and naphtha exhibited the highest groundwater contamination potential while kerosene and light crude oils were also likely to cause groundwater contamina-tion.Although volatile hydrocarbons in the WSFs of diesel and jet fuel do not easily exceed current regulatory standards,unregulated non-hydrocarbons may pose a more severe contamination risk to groundwater.Notably,the presence of significant benzene and toluene,hydrogenation and alkylation products(e.g.,C4-C5 alkylben-zenes,alkylindenes,alkyltetralins,and dihydro-indenes),cycloalkanes in WSFs can effectively be utilized for preliminary source identification of light distillates,middle distillates,and crude oils,respectively.展开更多
The surge in environmental pollution in recent years driven by numerous pollutants has necessitated the search for efficient removal methods.Phytoremediation is an eco-friendly technique that provides multiple benefit...The surge in environmental pollution in recent years driven by numerous pollutants has necessitated the search for efficient removal methods.Phytoremediation is an eco-friendly technique that provides multiple benefits over conventional methods of removing contaminants.Despite the numerous benefits of this technique,it has certain limitations that can be addressed by incorporating nanoparticles to improve its effectiveness.This review paper aims to explore the impact of heavy metal pollution on plants and human health.It highlights the role and mechanism of nanoparticles in enhancing phytoremediation,their application in the detection of heavy metals,and the strategies for the safe disposal of phytoremediation biomass.Biosynthesized nanoparticles are eco-friendly and non-toxic,with applications in biomedical and environmental fields.Nanoparticles can be used in the form of nano biosensors like smartphone-operated wireless sensors made from Cinnamomum camphora,enabling efficient detection of heavy metal ions.According to the studies,nanoparticles remove 80%–97%of heavy metals by various methods like reduction,precipitation,adsorption,etc.The phytoremediation biomass disposal can be done by heat treatment,phytomining,and microbial treatment with some modifications to further enhance their results.Phytoremediation is an environmentally friendly technique but requires further research and integration with biomass energy production to overcome scalability challenges and ensure safe biomass disposal.展开更多
Peroxymonosulfate(PMS)-based advanced oxidation processes(AOPs)are an effective way to remove emerging contaminants(ECs)from water.The catalytic process involving PMS is hindered by the suboptimal electron trans-fer e...Peroxymonosulfate(PMS)-based advanced oxidation processes(AOPs)are an effective way to remove emerging contaminants(ECs)from water.The catalytic process involving PMS is hindered by the suboptimal electron trans-fer efficiency of current catalysts,the further application of AOPs technology is limited.Here,it is proposed that the interfacial electric field can be controlled by bor(B)-doped FeNC catalysts,which shows significant advantages in the efficient generation,release and participation of reactive oxygen species(ROS)in the reaction.The super exchange interaction between Fe sites and N and B sites is realized through the directional transfer of electrons in the interfacial electric field,which ensures the high efficiency and stability of the PMS catalytic process.B doping increases the d orbitals distribution at Fermi level,which facilitates enhanced electron transition activity,thereby promoting the effective generation of (1)^O_(2).At the same time,orbital hybridization causes the center of the d band to move to a lower energy level,which not only contributes to the desorption process of (1)^O_(2),but also accelerates its release.In addition,B-doping also improved the adsorption capacity of organic pollutants and shortened the migration distance of ROS,thereby significantly improving the degradation efficiency of ECs.The B-doping strategy outlined offers a novel approach to the development of FeNC catalysts,it lays a theoretical foundation and offers technical insights for the integration of PMS/AOPs technology in the ECs management.展开更多
This study compares the environmental sustainability of five alternatives for the remediation of marine sediments of one of the most polluted coastal sites in Europe(Bagnoli-Coroglio bay,Mediterranean Sea),using the L...This study compares the environmental sustainability of five alternatives for the remediation of marine sediments of one of the most polluted coastal sites in Europe(Bagnoli-Coroglio bay,Mediterranean Sea),using the Life Cycle Assessment(LCA)methodology.The treatments are either in-situ or exsitu,the latter requiring an initial dredging to transport the contaminated sediments to the management site.More in detail,four ex-situ remediation technologies based on landfilling,bioremediation,electrokinetic technique and soil washing were identified.These technologies are compared to an in-situ strategy currently under validation for enhancing bioremediation of the polluted sediments of the Bagnoli-Coroglio site.Our results indicate that the disposal in landfilling site is the worst option in most categories(e.g.,650 kg CO_(2) eq./t of treated sediment,considering the nearest landfilling site),followed by the bioremediation,mainly due to the high energy demand.Electrokinetic remediation,soil washing,and innovative in-situ technology represent the most sustainable options.In particular,the new in-situ technology appears to be the least impacting in all categories(e.g.,54 kg CO_(2) eq./t of treated sediment),although it is expected to require longer treatment time(estimated up to 12 months based on its potential efficiency).It can reduce the impact on climate change more than 12 times compared to the disposal and 7 times compared to bioremediation in addition to the possibility to avoid/reduce the dredging operations and the consequent dispersion of pollutants.The results open relevant perspectives towards more eco-sustainable and costly effective actions for the reclamation of contaminated marine sediments.展开更多
Microbial contamination and the resulting corrosion in aircraft fuel system pose a serious threat to flight safety.Revealing the corrosion behavior and mechanism of fuel-degrading microorganisms on tank materials is c...Microbial contamination and the resulting corrosion in aircraft fuel system pose a serious threat to flight safety.Revealing the corrosion behavior and mechanism of fuel-degrading microorganisms on tank materials is crucial for developing effective mitigation strategies.In this study,the corrosion mechanisms of two representative hydrocarbon-degrading bacteria,Alcanivorax dieselolei and Microbacterium oxydans,toward AA7075 aluminum alloy,were systematically investigated.A combination of biofilm characterization,electrochemical testing,and surface/corrosion product characterization was employed.Both strains markedly accelerated the corrosion of AA7075,as evidence by the progressive decrease in polarization resistance and the pronounced rightward shift of the potentiodynamic polarization curves.Moreover,the difference between the pitting potential(E_(pit))and the corrosion potential(E_(corr))(ΔE=E_(pit)‒E_(corr))decreased due to microbial activities,indicating a pronounced tendency toward accelerated pitting corrosion.Corrosion morphology analysis revealed that both microbes promoted localized pitting corrosion.Furthermore,analysis of aviation kerosene composition indicated that both bacteria accelerated the degradation of C8 and C9 alkanes.These findings highlight the multiple threats of microbial contamination,material degradation,and fuel quality deterioration in fuel systems and underscore the need for targeted protection strategies for marine aviation operations.展开更多
[Objectives]To analyze the current status of heavy metal contamination in soils of vegetable cultivation bases located in Huichuan District,Zunyi City.[Methods]Soil samples from various depths within the vegetable cul...[Objectives]To analyze the current status of heavy metal contamination in soils of vegetable cultivation bases located in Huichuan District,Zunyi City.[Methods]Soil samples from various depths within the vegetable cultivation bases of Guanba Village,Sidu Village,and Banqiao Village in Huichuan District,Zunyi City,were selected as the subjects of this study.The concentrations of five heavy metals,including lead(Pb),mercury(Hg),cadmium(Cd),arsenic(As),and chromium(Cr),were measured at different soil depths.The Nemerow comprehensive pollution index method was employed to assess heavy metal contamination,and the analysis was conducted in accordance with the farmland environmental quality evaluation standards for edible agricultural products.[Results]The concentrations of Cd and As at the sample collection sites were relatively elevated.The pollution level of Cd reached grade III or above,indicating moderate contamination in certain topsoil areas.Most As concentrations corresponded to grade II and grade III pollution levels.In contrast,Hg,Pb,and Cr concentrations remained within the safety standards established for agricultural products.However,Cd and As levels predominantly surpassed these safety thresholds.Notably,Guanba Village and Sidu Village exhibited significant pollution levels,warranting comprehensive investigations into the sources of contamination.[Conclusions]This study offers valuable insights for advancing the sustainable development of local agriculture and for the prevention and management of soil contamination.展开更多
Groundwater is a key part of the terrestrial ecosystem,but it is vulnerable to pollution in the context of chemical industry development.Treating contaminated groundwater is challenging due to its stable water quality...Groundwater is a key part of the terrestrial ecosystem,but it is vulnerable to pollution in the context of chemical industry development.Treating contaminated groundwater is challenging due to its stable water quality,hidden contamination,and complex treatment requirements.Current research focuses on advanced treatment technologies,among which the advanced oxidation process(AOPs) of peroxomonosulfate(PMS) has great potential.Although there are many reviews of PMS-based AOP,most of them focus on surface water.This review aims to explore the activation reaction of PMS to groundwater by in-situ chemical oxidation(ISCO) technology,further study the reaction mechanism,compare the treatment effect of characteristic pollutants in the groundwater of the chemical industry park,propose new activation methods and catalyst selection,and provide guidance for future groundwater treatment research.展开更多
To address the deficiencies in comprehensive surface contamination prevention strategies within China's nitrate-affected regions,this research innovatively proposes the DITAPH model-a systematic framework integrat...To address the deficiencies in comprehensive surface contamination prevention strategies within China's nitrate-affected regions,this research innovatively proposes the DITAPH model-a systematic framework integrating groundwater nitrate vulnerability assessment and Nitrate Vulnerable Zones(NVZs)delineation through optimization of hydrogeological parameters.Based on detailed hydrogeological and hydrochemical investigations,the DITAPH model was applied in the plain areas of Quanzhou to evaluate its applicability.The model selected hydrogeological parameters(depth of groundwater,lithology of the vadose zone,topographic slope,aquifer water yield property),one climatic parameter(precipitation),and two anthropogenic parameters(land use type and population density)as assessment indicators.The results of the groundwater nitrate vulnerability assessment showed that the low,relatively low,relatively high,and high groundwater nitrate vulnerability zones in the study area accounted for 5.96%,35.44%,53.74%and 4.86%of the total area,respectively.Groundwater nitrate vulnerability was most strongly influenced by human activities,followed by groundwater depth and topographic slope.The high vulnerability zone is mainly affected by domestic and industrial wastewater,whereas the relatively high groundwater nitrate vulnerability zone is primarily influenced by agricultural activities.Validation of the DITAPH model revealed a significant positive correlation between the DITAPH index(DI)and nitrate concentration(ρ(NO3−)).The results of the NVZs delineated by the DITAPH model are reliable and can serve as a tool for water resource management planning,guiding the development of targeted measures in the NVZs to prevent groundwater contamination.展开更多
To assess the effectiveness of vaccination in contaminated environments,this study introduces a modeling framework that encompasses two transmission routes,namely direct human-to-human contact and indirect human-to-en...To assess the effectiveness of vaccination in contaminated environments,this study introduces a modeling framework that encompasses two transmission routes,namely direct human-to-human contact and indirect human-to-environment contact,as well as the implementation of new M72/AS01_(E)vaccine.Motivated by this,a coupled age-structured tuberculosis(TB)model is proposed.Its well-posedness requirement is verified using the integrated semigroup theory.Furthermore,this study presents a comprehensive analysis of threshold dynamics associated with the proposed model.Specifically,the global stability of the disease-free and positive steady states is demonstrated by employing Lyapunov functionals.Lastly,the effects of the vaccination with M72/AS01_(E)and contaminated environments on TB control are numerically simulated.Experimental results indicate that high concentrations of Mycobacterium tuberculosis in contaminated environments may somewhat impede TB control efforts,but that large-scale deployment of new vaccine could significantly reduce the prevalence of TB.展开更多
Groundwater and surface water contamination by PTE(Potentially Toxic Elements)was assessed in Ruashi and Annexe municipalities of Lubumbashi city.Analyses of seventy water samples collected from six drilled wells,eigh...Groundwater and surface water contamination by PTE(Potentially Toxic Elements)was assessed in Ruashi and Annexe municipalities of Lubumbashi city.Analyses of seventy water samples collected from six drilled wells,eight spade-sunk wells,one river and one spring in both municipalities in 2017 and 2018 were carried out by ICP-SF-MS(Inductively Coupled Plasma-Sector Field Mass Spectrometry).Twenty PTEs including aluminum,arsenic,barium,bismuth,cadmium,cesium,chromium,cobalt,copper,iron,lead,manganese,molybdenum,nickel,strontium,thallium,tungsten,uranium,vanadium and zinc were detected at various concentrations in each one of the samples.Many samples had concentrations and mean concentrations of PTEs,such as aluminum,cadmium,copper,iron,lead,manganese,nickel and zinc,higher than the respective acceptable limits set for drinking water by the EU(European Union),the USEPA(United States Environmental Protection Agency),and the WHO(World Health Organization)standards.Most PTEs being deleterious to human health even at very low concentrations,people who use the groundwater and surface water to meet their water needs in both Ruashi and Annexe municipalities are at risk.展开更多
Understanding the levels,causes,and sources of fluoride in groundwater is critical for public health,effective water resource management,and sustainable utilization.This study employs multivariate statistical methods,...Understanding the levels,causes,and sources of fluoride in groundwater is critical for public health,effective water resource management,and sustainable utilization.This study employs multivariate statistical methods,hazard quotient assessment,and geochemical analyses,such as mineral saturation index,ionic activities,and Gibbs diagrams,to investigate the hydrochemical characteristics,causes,and noncarcinogenic risks of fluoride in Red bed groundwater and geothermal water in the Guang'an area and neighboring regions.Approximately 9%of the Red bed groundwater samples contain fluoride concentrations exceeding 1 mg·L^(-1).The predominant water types identified are Cl-Na and HCO_(3)-Na,primarily influenced by evapotranspiration.Low-fluoride groundwater and high-fluoride geothermal water exhibit distinct hydrochemical types HCO_(3)-Ca and SO_(4)-Ca,respectively,which are mainly related to the weathering of carbonate,sulfate,and fluorite-containing rocks.Correlation analysis reveals that fluoride content in Red bed groundwater is positively associated with Na^(+),Cl^(-),SO_(4)^(2-),and TDS(r^(2)=0.45-0.64,p<0.01),while in geothermal water,it correlates strongly with pH,K^(+),Ca^(2+),and Mg^(2+)(r^(2)=0.52-0.80,p<0.05).Mineral saturation indices and ionic activities indicate that ion exchange processes and the dissolution of minerals such as carbonatite and fluorite are important sources of fluoride in groundwater.The enrichment of fluorine in the Red bed groundwater is linked to evaporation,cation exchange and dissolution of fluorite,caused by the lithologic characteristics of the red bed in this area.However,it exhibits minimal correlation with the geothermal water in the adjacent area.The noncarcinogenic health risk assessment indicates that 7%(n=5)of Red bed groundwater points exceed the fluoride safety limit for adults,while 12%(n=8)exceed the limit for children.These findings underscore the importance of avoiding highly fluoridated red bed groundwater as a direct drinking source and enhancing groundwater monitoring to mitigate health risks associated with elevated fluoride levels.展开更多
Aspergillus species produce aflatoxins and raise concerns about food safety in departmental stores and manufacturing mills.To address the risks posed by aflatoxins,and to advise the public on the highest quality rice ...Aspergillus species produce aflatoxins and raise concerns about food safety in departmental stores and manufacturing mills.To address the risks posed by aflatoxins,and to advise the public on the highest quality rice that serves as a nutritious food source,an inquiry following the guidelines outlined in both local and international standards of food safety for the presence of aflatoxins is an essential requirement.Therefore,16 white rice samples were selected randomly from low/high socio-economic departmental stores from 16 different localities.Grind powdered rice filtrate was extracted using chloroform.The filtrate applied on TLC plates and the amount of aflatoxin and moisture contents were determined.In the non-infected rice,moisture content was low(9.08%)whereas high[13.65%>12%(standard>value)]in infected ones.Four out of 8 samples of low-quality rice were contaminated with AFB_(1) and AFB_(2)(ranging from 22.2 to 29.3μg/kg).All the samples except one(22.3μg/kg)from high-quality rice were certified fit despite the contamination with AFB_(1).Furthermore,phylogenetic analysis showed Aspergillus flavus from unfit low(Long grain brown and Brown basmati)and high-quality(Basmati-198)rice whereas A.parasiticus from unfit low-quality Medium-grain brown rice.The presented research proves that the detection of fungi and aflatoxins in rice grains poses a huge risk to the health of consumers.Therefore,it is necessary to check the rice grains before distribution.展开更多
In drilling ultra-deep wells,the drilling fluid circulation usually causes erosion damage to downhole casing and drilling tools.However,the extent and process of this damage to the downhole tools is intricate and less...In drilling ultra-deep wells,the drilling fluid circulation usually causes erosion damage to downhole casing and drilling tools.However,the extent and process of this damage to the downhole tools is intricate and less understood.In order to systematically evaluate and clarify this damage process for different types of drilling fluid contamination,this research uses a high-temperature drilling fluid damage device to simulate the damage caused to the casing/drilling tools by various drilling fluid under a field thermal gradient.The results show that the drilling fluid residues are mainly solid-phase particles and organic components.The degree of casing/tool damage decreases with an increase in bottom hole temperature,and the casing/tool is least damaged within a temperature range of 150–180°C.Moreover,the surface of the casing/tool damaged by different types of drilling fluid shows different roughness,and the wettability of drilling fluid on the casing/tool surface increases with an increase in the degree of roughness.Oil-based drilling fluid have the strongest adhesion contamination on casing/drilling tools.In contrast,polysulfonated potassium drilling fluid and super-micro drilling fluid have the most potent erosion damage on casing/drilling tools.By analyzing the damage mechanism,it was established that the damage was mainly dominated by the abrasive wearing from solid-phase particles in concert with corrosion ions in drilling fluid,with solids producing many abrasion marks and corrosive ions causing a large number of pits.Clarifying drilling fluid's contamination and damage mechanism is significant in guiding the wellbore cleaning process and cutting associated costs.展开更多
The global concern surrounding the advancement of methods for treating wastewater and polluted soil has markedly increased over time.While electrochemical advanced oxidation processes(EAOPs)and biotreatments are commo...The global concern surrounding the advancement of methods for treating wastewater and polluted soil has markedly increased over time.While electrochemical advanced oxidation processes(EAOPs)and biotreatments are commonly employed technologies for remediating wastewater and polluted soil,their widespread adoption is hindered by their limitations,which include high costs associated with EAOPs and prolonged remediation time of biotreatments.In the review,we provided an overviewof EAOP technology and biotreatment,emphasizing the critical aspects involved in building a combined system.This review systematically evaluates recent research that combines EAOPswith bioremediation for treating wastewater or contaminated soil as pretreatment or post-treatment process.Research findings suggest that the combined treatment method represents a promising and competitive technology that can overcome some of the limitations of individual treatments.Additionally,we discussed the potential applications of this technology in varying levels of wastewater and soil pollution,as well as the underlying combination mechanisms.展开更多
Inefficient photo-carrier separation and sluggish photoreaction dynamics appreciably undermine the photocatalytic decontamination efficacy of photocatalysts.Herein,an S-scheme Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)heterojunc...Inefficient photo-carrier separation and sluggish photoreaction dynamics appreciably undermine the photocatalytic decontamination efficacy of photocatalysts.Herein,an S-scheme Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)heterojunction with interfacial Mo-S chemical bond is designed as an efficient photocatalyst.In this integrated photosystem,Bi2MoO6 and Mn_(0.5)Cd_(0.5)S function as oxidation and reduction centers of Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)microspheres,respectively.Importantly,the unique charge transfer mechanism in the chemically bonded S-scheme heterojunction with Mo-S bond as atom-scale charge transport highway effectively inhibits the photocorrosion of Mn_(0.5)Cd_(0.5)S and the recombination of photo-generated electron-hole pairs,endowing Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)photocatalyst with excellent photocatalytic decontamination performance and stability.Besides,integration of Mn_(0.5)Cd_(0.5)S nanocrystals into Bi2MoO6 improves hydrophilicity,conducive to the photoreactions.Strikingly,compared with Mn_(0.5)Cd_(0.5)S and Bi2MoO6,the Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)unveils much augmented photoactivity in tetracycline eradication,among which Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)-2 possesses the highest activity with the rate constant up to 0.0323 min-1,prominently outperforming other counterparts.This research offers a chemical bonding engineering combining with S-scheme heterojunction strategy for constructing extraordinary photocatalysts for environmental purification.展开更多
基金financially supported by the Program of Co-construction and Development of Universities(No.8000019z050201)。
文摘Emeishan large igneous province (ELIP),one of the largest continental volcanic provinces worldwide (e.g.,Karoo),is extensively distributed along the western margin of the Yangtze Block.Even though the consensus that the ELIP is of a plume-related origin has been reached for decades,the role of crustal contamination in the petrogenesis of these basalts is still debatable so far.This paper firstly reports the Ba isotopic compositions of the continental flood basalts from the Lijiang,Miyi and Emeishan regions to discuss the genesis of basalts from the ELIP.According to their TiO_(2) contents and Ti/Y ratios,these basalts are divided into two groups,the low-Ti basalts from Lijiang and the high-Ti basalts from Miyi and Emeishan.The Ba isotopic compositions show that the low-Ti basalts have the δ^(138/134)Ba values from-0.33‰to+0.23‰with an average of-0.02‰±0.40‰,and the high-Ti basalts from -0.38‰to+0.38‰with an average of 0.038‰±0.36‰,all of which show a wider range of Ba isotopes relative to that of the primitive mantle (PM).This is unlikely to be explained by partial melting,fractional crystallization or even chemical weathering owing to little Ba isotopic fractionation during these processes.In contrast,variable extents of crustal contamination into the basaltic magmas more likely resulted in such isotopic diversity.The ratios of incompatible elements (e.g.,Nb/U,La/Nb,and Nb/Y) further suggest that the low-Ti basalts experienced higher degrees of crustal contaminations than those high-Ti basalts,which is well consistent with their spatial distributions.In general,the basaltic magmas in the ELIP were probably contaminated by different degrees of crustal materials during their upwelling to the surface.
文摘The present study aimed to investigate the microbial populations such a bacteria and fungi contamination present in the herbal medicinal preparations (Lepidium sativum, Nigella sativa, Cuminum cyminum, Foeniculum vulgare, Pimpinella anisum, Trigoneela foenum-graecum, Cinnamomum verum, peel coffee, Alchemilla valgaris, Vitex agnus-castus) commonly available in different parts of Riyadh, Saudi Arabia. To determine the contamination of the herbal products, experiments such as total aerobic bacterial plate counts were evaluated by various plating techniques. The isolation and identification of fungi were done using czapek dox agar and potato dextrose agar. The results showed that a total of herbal remedies were contaminated with bacteria and fungi (100%). Among the contaminated products, peel of coffee and Vitex angnus-castus were noted more contamination than the other herbal medicinal plants. The results confirmed that the traditionally prepared herbal medications in Riyadh city are likely to be contaminated with a wide variety of potentially pathogenic bacteria and fungi. Therefore, before consumption, the quality assurance of these products should be thoroughly enforced and monitored in the production and distribution of herbal preparations. In conclusion, the present study gives proper evidence that the consumed herbal products contain different levels of pathogenic microbes.
文摘One of the methods used in practice for the purification of wastewater from vegetable-processing enterprises is biological method of aerobic purification. With the aim to increase air-tank capacity used in traditional systems of biochemical purification of wastewater, different ways effecting to the process of vital activity of microorganisms of active sludge are applied. On the one hand, using the compositions of different salts and complex organic biogenous supplements prevents from the accumulation of some anions in the amounts exceeding the limited concentration, on the other hand- allows different groups of microorganisms to choose biogenous elements, which they assimilate easily and fully. It is known, that compounds of silicon and germanium can cause stimulating effects [1] to the organisms of active sludge. The goal of present studies is the intensification of biological processes of oxidation of organic contamination in wastewater by new bio-degradable chemical compounds or compositions on their basis, and by bio-sorbents.
文摘The presence of microscopic spores in the air affects the quality of air inhaled by animals including humans.Microbial contamination of air impacts the well-being of occupants of an indoor environment,sometimes with dire consequences.The study investigated fungal contaminations of indoor and outdoor air of the Hospital,Library and Senior Common Room(SCR)of the University of Cape Coast,Ghana.Indoor and outdoor air was sampled using the Koch’s sedimentation method.Colony forming units per cubic meter of air(cfu/m^(3))were determined with the Omeliansky formula.The isolated fungi were identified based on morphological and growth characteristics.For indoor air,the least colony counts were recorded in the SCR for both morning and afternoon samples,whilst the Hospital air had the highest colony counts.For outdoor air,the colony counts were lower in SCR and the Library for both morning and afternoon samples compared to the Hospital.The results further indicated that indoor concentrations of fungi,for morning and afternoon,ranged between 4.0x10^(4) and 2.1x10^(5) cfu/m^(3),whereas outdoor concentrations of fungi ranged between 1.1x105 and 3.0x10^(5) cfu/m^(3),revealing an overall higher levels of contamination of outdoor air than indoor air at all the three buildings.Consequently,estimated indoor/outdoor(I/O)concentration ratios of fungi revealed an exogenous source of indoor contaminations at all the three buildings sampled.Fungi isolated from indoor and outdoor air were of the genera Aspergillus,Curvularia,Cylindrocarpon,Fusarium,Mucor,Neurospora,Penicillium and Rhodotorula.We conclude that indoor and outdoor air of the buildings sampled were contaminated with airborne fungi;however,based on estimated I/O ratios,the indoor ambient conditions of the buildings were good.The implication of findings of this study is that the presence of airborne fungal contaminants of indoor and outdoor workplace environment may pose serious occupational health consequences,hence low productivity.
文摘To assess contamination levels,14 samples were taken from mining sites in the Ngoura gold mining area,to determine the possible ecological hazards of heavy metals(Al,Mn,As,Ba,V,Cr,Ag,Pb,Hg,Y,Th and U).Physico-chemical parameters(pH,OM,CEC,Available P,and EC)were analysed.Using Induc-tively Coupled Plasma Mass Spectrometry(ICP-MS),heavy metals were iden-tified.The contaminations were estimated using the following methods:en-richment factor(EF),contamination factor(CF),mean contamination index(Im),pollution load index(PLI),geo-accumulation index(I-Geo),and ecolog-ical risk index(Ri).Findings indicated that mining materials exhibit acidic to highly alkaline pH(5.2 to 9.8),are non-saline(EC<250µS/cm),with low to very high OM(1.20 to 6.51),moderate to very high CEC(14.11 to 45 meq/100g),and very low to medium available phosphorus(7 to 34.34 mg/kg).Heavy metal analysis revealed concentrations(mg/kg)exceeding UCC values:soils near mines:Hg(24.81),Pb(18.99),Th(8.46)mining wastes:Y(97.66),Hg(26.96),Pb(25.85),Th(169.96),U(9.8)residues:Hg(19.49),Pb(30.25),Th(21.12),U(16.5)sediments:Ba(682.75),Y(65.75),Hg(4.2),Pb(26.93),Th(236.65),U(16.15).Contamination indices(EF,I-Geo,CF,Im,PLI)revealed contamina-tion by Hg,Y,Pb,Th,and U,with extreme enrichment of Hg across all mate-rials.I-Geo indicated extreme Hg contamination,while Im confirmed contam-ination in most samples.Hg posed a very high ecological risk,making it the principal contaminant in the Ngoura mining area.Phytoremediation can help to reduce the contaminations in this study area.
基金supported by the National Science Foundation of China(Nos.42177042,and 42477051)the National Key R&D Program of China(No.2023YFC3708700)the Science Foundation of China University of Petroleum-Beijing(No.2462022QNXZ006).
文摘Petroleum leakage is a major groundwater contamination source,with chemical composition of water soluble fractions(WSFs)from diverse oil sources significantly impacting groundwater quality and source identification.The aim of this study was to assess impact of 15 diverse oils on groundwater quality and environmental forensics based on oil-water equilibrium experiments.Our results indicate that contamination of groundwater by gasoline and naphtha is primarily attributed to volatile hydrocarbons,while pollution from diesel,kerosene,and crude oil is predominantly from non-hydrocarbons.Rapid determination of the extent of non-hydrocarbon pollution in WSFs was achieved through a new quantitative index.Gasoline and naphtha exhibited the highest groundwater contamination potential while kerosene and light crude oils were also likely to cause groundwater contamina-tion.Although volatile hydrocarbons in the WSFs of diesel and jet fuel do not easily exceed current regulatory standards,unregulated non-hydrocarbons may pose a more severe contamination risk to groundwater.Notably,the presence of significant benzene and toluene,hydrogenation and alkylation products(e.g.,C4-C5 alkylben-zenes,alkylindenes,alkyltetralins,and dihydro-indenes),cycloalkanes in WSFs can effectively be utilized for preliminary source identification of light distillates,middle distillates,and crude oils,respectively.
文摘The surge in environmental pollution in recent years driven by numerous pollutants has necessitated the search for efficient removal methods.Phytoremediation is an eco-friendly technique that provides multiple benefits over conventional methods of removing contaminants.Despite the numerous benefits of this technique,it has certain limitations that can be addressed by incorporating nanoparticles to improve its effectiveness.This review paper aims to explore the impact of heavy metal pollution on plants and human health.It highlights the role and mechanism of nanoparticles in enhancing phytoremediation,their application in the detection of heavy metals,and the strategies for the safe disposal of phytoremediation biomass.Biosynthesized nanoparticles are eco-friendly and non-toxic,with applications in biomedical and environmental fields.Nanoparticles can be used in the form of nano biosensors like smartphone-operated wireless sensors made from Cinnamomum camphora,enabling efficient detection of heavy metal ions.According to the studies,nanoparticles remove 80%–97%of heavy metals by various methods like reduction,precipitation,adsorption,etc.The phytoremediation biomass disposal can be done by heat treatment,phytomining,and microbial treatment with some modifications to further enhance their results.Phytoremediation is an environmentally friendly technique but requires further research and integration with biomass energy production to overcome scalability challenges and ensure safe biomass disposal.
基金supported by the National Natural Science Foundation of China(No.22278156)the Guangdong Special Support Program Project(No.2021JC060580)+1 种基金the Young Elite Scientists Sponsorship Program by CAST-Doctoral Student Special Plan,the China Scholarship Council Program(No.202406150148)the Natural Science Foundation of Guangdong Province(No.2023A1515011186).
文摘Peroxymonosulfate(PMS)-based advanced oxidation processes(AOPs)are an effective way to remove emerging contaminants(ECs)from water.The catalytic process involving PMS is hindered by the suboptimal electron trans-fer efficiency of current catalysts,the further application of AOPs technology is limited.Here,it is proposed that the interfacial electric field can be controlled by bor(B)-doped FeNC catalysts,which shows significant advantages in the efficient generation,release and participation of reactive oxygen species(ROS)in the reaction.The super exchange interaction between Fe sites and N and B sites is realized through the directional transfer of electrons in the interfacial electric field,which ensures the high efficiency and stability of the PMS catalytic process.B doping increases the d orbitals distribution at Fermi level,which facilitates enhanced electron transition activity,thereby promoting the effective generation of (1)^O_(2).At the same time,orbital hybridization causes the center of the d band to move to a lower energy level,which not only contributes to the desorption process of (1)^O_(2),but also accelerates its release.In addition,B-doping also improved the adsorption capacity of organic pollutants and shortened the migration distance of ROS,thereby significantly improving the degradation efficiency of ECs.The B-doping strategy outlined offers a novel approach to the development of FeNC catalysts,it lays a theoretical foundation and offers technical insights for the integration of PMS/AOPs technology in the ECs management.
基金support in the literature analysis.This study has been carried out in the framework of the project funded by EU entitled“Bioremediation of contaminated sediments in coastal areas of exindustrial sites-LIFE SEDREMED”(No.LIFE20 ENV/IT/000572).
文摘This study compares the environmental sustainability of five alternatives for the remediation of marine sediments of one of the most polluted coastal sites in Europe(Bagnoli-Coroglio bay,Mediterranean Sea),using the Life Cycle Assessment(LCA)methodology.The treatments are either in-situ or exsitu,the latter requiring an initial dredging to transport the contaminated sediments to the management site.More in detail,four ex-situ remediation technologies based on landfilling,bioremediation,electrokinetic technique and soil washing were identified.These technologies are compared to an in-situ strategy currently under validation for enhancing bioremediation of the polluted sediments of the Bagnoli-Coroglio site.Our results indicate that the disposal in landfilling site is the worst option in most categories(e.g.,650 kg CO_(2) eq./t of treated sediment,considering the nearest landfilling site),followed by the bioremediation,mainly due to the high energy demand.Electrokinetic remediation,soil washing,and innovative in-situ technology represent the most sustainable options.In particular,the new in-situ technology appears to be the least impacting in all categories(e.g.,54 kg CO_(2) eq./t of treated sediment),although it is expected to require longer treatment time(estimated up to 12 months based on its potential efficiency).It can reduce the impact on climate change more than 12 times compared to the disposal and 7 times compared to bioremediation in addition to the possibility to avoid/reduce the dredging operations and the consequent dispersion of pollutants.The results open relevant perspectives towards more eco-sustainable and costly effective actions for the reclamation of contaminated marine sediments.
基金financially supported by the National Natural Science Foundation of China (No. 52371056)the Liaoning Provincial Youth Science Fund Project, China (Category B, No. 2025JH6/101000010)+1 种基金the Guangdong Basic and Applied Basic Research Foundation, China (No. 2024A1515240055)funding from the China Scholarship Council
文摘Microbial contamination and the resulting corrosion in aircraft fuel system pose a serious threat to flight safety.Revealing the corrosion behavior and mechanism of fuel-degrading microorganisms on tank materials is crucial for developing effective mitigation strategies.In this study,the corrosion mechanisms of two representative hydrocarbon-degrading bacteria,Alcanivorax dieselolei and Microbacterium oxydans,toward AA7075 aluminum alloy,were systematically investigated.A combination of biofilm characterization,electrochemical testing,and surface/corrosion product characterization was employed.Both strains markedly accelerated the corrosion of AA7075,as evidence by the progressive decrease in polarization resistance and the pronounced rightward shift of the potentiodynamic polarization curves.Moreover,the difference between the pitting potential(E_(pit))and the corrosion potential(E_(corr))(ΔE=E_(pit)‒E_(corr))decreased due to microbial activities,indicating a pronounced tendency toward accelerated pitting corrosion.Corrosion morphology analysis revealed that both microbes promoted localized pitting corrosion.Furthermore,analysis of aviation kerosene composition indicated that both bacteria accelerated the degradation of C8 and C9 alkanes.These findings highlight the multiple threats of microbial contamination,material degradation,and fuel quality deterioration in fuel systems and underscore the need for targeted protection strategies for marine aviation operations.
基金Supported by Undergraduate Innovation and Entrepreneurship Training Program of Guizhou Province(2024106640823)Natural Science Research Project of Guizhou Provincial Department of Education(QJJ[2023]043)Zunyi Science and Technology Innovation Team Project(ZKCTD008).
文摘[Objectives]To analyze the current status of heavy metal contamination in soils of vegetable cultivation bases located in Huichuan District,Zunyi City.[Methods]Soil samples from various depths within the vegetable cultivation bases of Guanba Village,Sidu Village,and Banqiao Village in Huichuan District,Zunyi City,were selected as the subjects of this study.The concentrations of five heavy metals,including lead(Pb),mercury(Hg),cadmium(Cd),arsenic(As),and chromium(Cr),were measured at different soil depths.The Nemerow comprehensive pollution index method was employed to assess heavy metal contamination,and the analysis was conducted in accordance with the farmland environmental quality evaluation standards for edible agricultural products.[Results]The concentrations of Cd and As at the sample collection sites were relatively elevated.The pollution level of Cd reached grade III or above,indicating moderate contamination in certain topsoil areas.Most As concentrations corresponded to grade II and grade III pollution levels.In contrast,Hg,Pb,and Cr concentrations remained within the safety standards established for agricultural products.However,Cd and As levels predominantly surpassed these safety thresholds.Notably,Guanba Village and Sidu Village exhibited significant pollution levels,warranting comprehensive investigations into the sources of contamination.[Conclusions]This study offers valuable insights for advancing the sustainable development of local agriculture and for the prevention and management of soil contamination.
基金supported by the National Key Research and Development Program of China (No.2023YFC3708005)the National Natural Science Foundation of China (Nos.21872102,22172080)the Fundamental Research Funds for the Central Universities (Nankai University,No.63241208)。
文摘Groundwater is a key part of the terrestrial ecosystem,but it is vulnerable to pollution in the context of chemical industry development.Treating contaminated groundwater is challenging due to its stable water quality,hidden contamination,and complex treatment requirements.Current research focuses on advanced treatment technologies,among which the advanced oxidation process(AOPs) of peroxomonosulfate(PMS) has great potential.Although there are many reviews of PMS-based AOP,most of them focus on surface water.This review aims to explore the activation reaction of PMS to groundwater by in-situ chemical oxidation(ISCO) technology,further study the reaction mechanism,compare the treatment effect of characteristic pollutants in the groundwater of the chemical industry park,propose new activation methods and catalyst selection,and provide guidance for future groundwater treatment research.
基金supported by the National Key Research and Development Program of China(No.2022YFF1301301)the Natural Science Foundation of Xiamen Municipality(No.3502Z202472047)the Geological Survey Program of China Geological Survey(DD20190303).
文摘To address the deficiencies in comprehensive surface contamination prevention strategies within China's nitrate-affected regions,this research innovatively proposes the DITAPH model-a systematic framework integrating groundwater nitrate vulnerability assessment and Nitrate Vulnerable Zones(NVZs)delineation through optimization of hydrogeological parameters.Based on detailed hydrogeological and hydrochemical investigations,the DITAPH model was applied in the plain areas of Quanzhou to evaluate its applicability.The model selected hydrogeological parameters(depth of groundwater,lithology of the vadose zone,topographic slope,aquifer water yield property),one climatic parameter(precipitation),and two anthropogenic parameters(land use type and population density)as assessment indicators.The results of the groundwater nitrate vulnerability assessment showed that the low,relatively low,relatively high,and high groundwater nitrate vulnerability zones in the study area accounted for 5.96%,35.44%,53.74%and 4.86%of the total area,respectively.Groundwater nitrate vulnerability was most strongly influenced by human activities,followed by groundwater depth and topographic slope.The high vulnerability zone is mainly affected by domestic and industrial wastewater,whereas the relatively high groundwater nitrate vulnerability zone is primarily influenced by agricultural activities.Validation of the DITAPH model revealed a significant positive correlation between the DITAPH index(DI)and nitrate concentration(ρ(NO3−)).The results of the NVZs delineated by the DITAPH model are reliable and can serve as a tool for water resource management planning,guiding the development of targeted measures in the NVZs to prevent groundwater contamination.
文摘To assess the effectiveness of vaccination in contaminated environments,this study introduces a modeling framework that encompasses two transmission routes,namely direct human-to-human contact and indirect human-to-environment contact,as well as the implementation of new M72/AS01_(E)vaccine.Motivated by this,a coupled age-structured tuberculosis(TB)model is proposed.Its well-posedness requirement is verified using the integrated semigroup theory.Furthermore,this study presents a comprehensive analysis of threshold dynamics associated with the proposed model.Specifically,the global stability of the disease-free and positive steady states is demonstrated by employing Lyapunov functionals.Lastly,the effects of the vaccination with M72/AS01_(E)and contaminated environments on TB control are numerically simulated.Experimental results indicate that high concentrations of Mycobacterium tuberculosis in contaminated environments may somewhat impede TB control efforts,but that large-scale deployment of new vaccine could significantly reduce the prevalence of TB.
基金funding received from UNESCO-SIDA Project as well as Professor Martine Leermakers and Professor Willy Baeyens for their financial help to analyze the water samples in their laboratory at VUB.Acknowledgements
文摘Groundwater and surface water contamination by PTE(Potentially Toxic Elements)was assessed in Ruashi and Annexe municipalities of Lubumbashi city.Analyses of seventy water samples collected from six drilled wells,eight spade-sunk wells,one river and one spring in both municipalities in 2017 and 2018 were carried out by ICP-SF-MS(Inductively Coupled Plasma-Sector Field Mass Spectrometry).Twenty PTEs including aluminum,arsenic,barium,bismuth,cadmium,cesium,chromium,cobalt,copper,iron,lead,manganese,molybdenum,nickel,strontium,thallium,tungsten,uranium,vanadium and zinc were detected at various concentrations in each one of the samples.Many samples had concentrations and mean concentrations of PTEs,such as aluminum,cadmium,copper,iron,lead,manganese,nickel and zinc,higher than the respective acceptable limits set for drinking water by the EU(European Union),the USEPA(United States Environmental Protection Agency),and the WHO(World Health Organization)standards.Most PTEs being deleterious to human health even at very low concentrations,people who use the groundwater and surface water to meet their water needs in both Ruashi and Annexe municipalities are at risk.
基金supported by the China Geological Survey Project(Nos.DD20220864 and DD20243077).
文摘Understanding the levels,causes,and sources of fluoride in groundwater is critical for public health,effective water resource management,and sustainable utilization.This study employs multivariate statistical methods,hazard quotient assessment,and geochemical analyses,such as mineral saturation index,ionic activities,and Gibbs diagrams,to investigate the hydrochemical characteristics,causes,and noncarcinogenic risks of fluoride in Red bed groundwater and geothermal water in the Guang'an area and neighboring regions.Approximately 9%of the Red bed groundwater samples contain fluoride concentrations exceeding 1 mg·L^(-1).The predominant water types identified are Cl-Na and HCO_(3)-Na,primarily influenced by evapotranspiration.Low-fluoride groundwater and high-fluoride geothermal water exhibit distinct hydrochemical types HCO_(3)-Ca and SO_(4)-Ca,respectively,which are mainly related to the weathering of carbonate,sulfate,and fluorite-containing rocks.Correlation analysis reveals that fluoride content in Red bed groundwater is positively associated with Na^(+),Cl^(-),SO_(4)^(2-),and TDS(r^(2)=0.45-0.64,p<0.01),while in geothermal water,it correlates strongly with pH,K^(+),Ca^(2+),and Mg^(2+)(r^(2)=0.52-0.80,p<0.05).Mineral saturation indices and ionic activities indicate that ion exchange processes and the dissolution of minerals such as carbonatite and fluorite are important sources of fluoride in groundwater.The enrichment of fluorine in the Red bed groundwater is linked to evaporation,cation exchange and dissolution of fluorite,caused by the lithologic characteristics of the red bed in this area.However,it exhibits minimal correlation with the geothermal water in the adjacent area.The noncarcinogenic health risk assessment indicates that 7%(n=5)of Red bed groundwater points exceed the fluoride safety limit for adults,while 12%(n=8)exceed the limit for children.These findings underscore the importance of avoiding highly fluoridated red bed groundwater as a direct drinking source and enhancing groundwater monitoring to mitigate health risks associated with elevated fluoride levels.
基金supported by Princess Nourah bint Abdulrahman University Researchers Supporting Project Number(PNURSP2025R317),Princess Nourah bintAbdulrahman University,Riyadh,Saudi Arabia.
文摘Aspergillus species produce aflatoxins and raise concerns about food safety in departmental stores and manufacturing mills.To address the risks posed by aflatoxins,and to advise the public on the highest quality rice that serves as a nutritious food source,an inquiry following the guidelines outlined in both local and international standards of food safety for the presence of aflatoxins is an essential requirement.Therefore,16 white rice samples were selected randomly from low/high socio-economic departmental stores from 16 different localities.Grind powdered rice filtrate was extracted using chloroform.The filtrate applied on TLC plates and the amount of aflatoxin and moisture contents were determined.In the non-infected rice,moisture content was low(9.08%)whereas high[13.65%>12%(standard>value)]in infected ones.Four out of 8 samples of low-quality rice were contaminated with AFB_(1) and AFB_(2)(ranging from 22.2 to 29.3μg/kg).All the samples except one(22.3μg/kg)from high-quality rice were certified fit despite the contamination with AFB_(1).Furthermore,phylogenetic analysis showed Aspergillus flavus from unfit low(Long grain brown and Brown basmati)and high-quality(Basmati-198)rice whereas A.parasiticus from unfit low-quality Medium-grain brown rice.The presented research proves that the detection of fungi and aflatoxins in rice grains poses a huge risk to the health of consumers.Therefore,it is necessary to check the rice grains before distribution.
基金support and funding from the CNPC Project(2021ZG10)National Natural Science Foundation of China(No.52174047)Sinopec Project(No.P23138).
文摘In drilling ultra-deep wells,the drilling fluid circulation usually causes erosion damage to downhole casing and drilling tools.However,the extent and process of this damage to the downhole tools is intricate and less understood.In order to systematically evaluate and clarify this damage process for different types of drilling fluid contamination,this research uses a high-temperature drilling fluid damage device to simulate the damage caused to the casing/drilling tools by various drilling fluid under a field thermal gradient.The results show that the drilling fluid residues are mainly solid-phase particles and organic components.The degree of casing/tool damage decreases with an increase in bottom hole temperature,and the casing/tool is least damaged within a temperature range of 150–180°C.Moreover,the surface of the casing/tool damaged by different types of drilling fluid shows different roughness,and the wettability of drilling fluid on the casing/tool surface increases with an increase in the degree of roughness.Oil-based drilling fluid have the strongest adhesion contamination on casing/drilling tools.In contrast,polysulfonated potassium drilling fluid and super-micro drilling fluid have the most potent erosion damage on casing/drilling tools.By analyzing the damage mechanism,it was established that the damage was mainly dominated by the abrasive wearing from solid-phase particles in concert with corrosion ions in drilling fluid,with solids producing many abrasion marks and corrosive ions causing a large number of pits.Clarifying drilling fluid's contamination and damage mechanism is significant in guiding the wellbore cleaning process and cutting associated costs.
基金supported by the National Natural Science Foundation of China(No.51709103)the Natural Science Foundation of Hunan Province,China(Nos.2018JJ3242 and 2021JJ30362)the Science and Technology Innovation Leading Plan of High Tech Industry in Hunan Province(No.2021GK4055).
文摘The global concern surrounding the advancement of methods for treating wastewater and polluted soil has markedly increased over time.While electrochemical advanced oxidation processes(EAOPs)and biotreatments are commonly employed technologies for remediating wastewater and polluted soil,their widespread adoption is hindered by their limitations,which include high costs associated with EAOPs and prolonged remediation time of biotreatments.In the review,we provided an overviewof EAOP technology and biotreatment,emphasizing the critical aspects involved in building a combined system.This review systematically evaluates recent research that combines EAOPswith bioremediation for treating wastewater or contaminated soil as pretreatment or post-treatment process.Research findings suggest that the combined treatment method represents a promising and competitive technology that can overcome some of the limitations of individual treatments.Additionally,we discussed the potential applications of this technology in varying levels of wastewater and soil pollution,as well as the underlying combination mechanisms.
文摘Inefficient photo-carrier separation and sluggish photoreaction dynamics appreciably undermine the photocatalytic decontamination efficacy of photocatalysts.Herein,an S-scheme Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)heterojunction with interfacial Mo-S chemical bond is designed as an efficient photocatalyst.In this integrated photosystem,Bi2MoO6 and Mn_(0.5)Cd_(0.5)S function as oxidation and reduction centers of Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)microspheres,respectively.Importantly,the unique charge transfer mechanism in the chemically bonded S-scheme heterojunction with Mo-S bond as atom-scale charge transport highway effectively inhibits the photocorrosion of Mn_(0.5)Cd_(0.5)S and the recombination of photo-generated electron-hole pairs,endowing Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)photocatalyst with excellent photocatalytic decontamination performance and stability.Besides,integration of Mn_(0.5)Cd_(0.5)S nanocrystals into Bi2MoO6 improves hydrophilicity,conducive to the photoreactions.Strikingly,compared with Mn_(0.5)Cd_(0.5)S and Bi2MoO6,the Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)unveils much augmented photoactivity in tetracycline eradication,among which Mn_(0.5)Cd_(0.5)S/Bi_(2)MoO_(6)-2 possesses the highest activity with the rate constant up to 0.0323 min-1,prominently outperforming other counterparts.This research offers a chemical bonding engineering combining with S-scheme heterojunction strategy for constructing extraordinary photocatalysts for environmental purification.
