荒漠草地中氮添加与多环芳烃降解的关系

多环芳烃作为环境污染物中一类极为重要的物质,探索它的去除方法吸引了全球环境学者及政府的高度重视。大气氮沉降在过去几十年不断增加,已影响到陆地生态系统氮循环过程。但目前,氮沉降与多环芳烃降解之间的关系尚不明确。通过在新疆克拉玛依市石油化工厂附近的荒漠草地上,模拟氮沉降实验,通过在4氮添加梯度(CK=0;N1=10;N2=30;N3=90 kg N hm-2 a-1)上调查土壤中16种优先控制多环芳烃的含量和总量(∑PAHs),以及它们与生物非生物环境因子(土壤环境因子、土壤酶活性和土壤微生物功能多样性)之间的关系,旨在揭示氮沉降对多环芳烃降解的影响。结果表明:除苊烯(Acenaphthylene)和苊(Acenaphthene)两种多环芳烃在4个N添加梯度上未检测到含量外,∑PAHs和其他14种优先控制多环芳烃在土壤中的含量均随氮添加量增加显著减小(N2≤N3<N1<CK)(P<0.01);对照样地(CK)在施氮前后,低高分子多环芳烃含量的比值>1.00,且0.40<荧蒽(Fluoranthene)/[(荧蒽(Fluoranthene)+芘(Pyrene)]<0.50,石油污染物是当地土壤中多环芳烃的主要来源;9月份克拉玛依市荒漠草地土壤中∑PAHs约(28.91±2.32) mg/kg,属于多环芳烃重污染土壤;广义线性混合效应模型结果显示,在大多数情况下,∑PAHs和14种多环芳烃的含量与土壤有机质、铵态氮、硝态氮、总氮、有效磷和脲酶活性显著相关(P<0.05),但其与生物非生物环境因子之间的回归关系在不同种类多环芳烃之间差异较大。综上可知,土壤中多环芳烃的降解是一个非常复杂的过程,它是自身属性、植物根系和土壤微生物等多重因子相互共同作用的结果。在干旱区荒漠草地中,氮添加能提升土壤中营养物质的可利用性、植物根系和土壤微生物的活性,有利于降解土壤多环芳烃。

全氟和多氟烷基化合物的分析检测

全氟和多氟烷基化合物(Perfluorinated and Polyfluoroalkyl Substances,PFAS)已成为引人关注的新型污染物,其检测难点包括微量或痕量分析、复杂PFAS组分的定量分析等。对PFAS的分析和检测,除了传统的高效液相色谱-质谱(HPLC-MS)法之外,新的分析测试技术也不断涌现,一方面有效补充了传统的实验室方法,另一方面也使得现场检测成为可能,特别是那些能够快速得到半定量结果的预筛选检测技术。本文试图对这些新报道的PFAS的测试技术进行评述,包括电化学检测、光学检测,以及基于智能手机应用程序的检测,并对未来的研究方向进行了展望。

Amelioration of Salinity Stress in Maize Seed Germination and Seedling Growth Attributes through Seed Priming

Germination of seeds and growth of seedling respond to seed priming as priming can guard the damage of salinity stress. A study conducted in the net house of the Department of Agronomy, BAU, Mymensingh during the period from November 2012 to April 2013 investigated the ameliorative effect of seed priming on seed germination and seedling attributes of maize under various salinity stress conditions. The experiment consisted of five seed priming and four salinity levels (NaCl) and laid out in a Completely Randomized Design (CRD) with three replications. Seed germination and seedling attributes of maize varied due to salinity stress and priming. The highest seed germination (95.7%) was recorded when no stress was imposed under hydropriming (48 hours). The germination of seeds performed even well (92.3%) when treated with hydropriming (48 hours) and NaCl@0.25 dS&#183m-1 which was followed by hydropriming (24 hours) under no salinity imposed and NaCl@0.25 dS&#183m-1 salinity. Hydropriming for 48 hours without salt stress performed the best on number of leaves seedling-1 (8), shoot length (28.2 cm), root length (14.5 cm), fresh weight (100.8 g) and dry weight of seedling (50.3 g). The germination and seedling growth parameters were reduced with the increase in salinity levels irrespective of priming while all seed priming treatments showed ameliorative effects. However, reduction in seed germination and seedling attributes were minimal with hydropriming for 48 hours. The results revealed that priming of maize seeds could be used for amelioration of salinity stress and hydropriming for 48 hours appeared as the best seed priming treatment.

Chromium adsorption on surface activated biochar made from tannery liming sludge:A waste-to-wealth approach

In a beamhouse,liming plays a key role in the removal of hair/wool and epidermis,but problems are created when waste liming sludge is discharged to the environment.The treatment of tannery wastewater is another major challenge to the industry.In this study,thermally-activated biochars derived from liming sludge were studied for their effective adsorption of chromium(Cr)from the tannery wastewater.The thermally activated biochars(B500,B550,B600,and B650)were prepared at different temperatures from the liming sludge.Their characteristics before and after the treatment were investigated using Fourier transform infrared spectroscopy,energy dispersive X-ray spectroscopy,Bru-nauer-Emmett-Teller,and scanning electron microscopy analyses.The related functional groups(C-H,O-H,C-N,and=C-O)and chromium adsorption capacity were determined according to the surface morphology,element contents(C,O,Ca,Na,Al,Mg,and Si),surface area(5.8-9.2 m^(2)/g),pore size(5.22-5.53 nm),and particle size(652-1034 nm)of the experimental biochars.The biochar originated at 600°C from the tannery liming sludge(B600)had a greater surface area with a chromium adsorption capacity of 99.8%in comparison to B500,B550,and B650 biochars.This study developed an innovative way of utilizing liming sludge waste to minimize the pollution load and wastewater treatment cost in the tannery industry.

Groundwater arsenic poisoning in a primary educational institution:health risks to school-going children

This study aimed to estimate arsenic(As)and iron(Fe)content in tubewell water(n=58)in primary educational institutions and subsequently assess the health risks to school-going children.Results described that the As concentration ranged between 0.002 and 0.994 mg L^(-1)with an average value of 0.044 mg L^(-1);which exceeded the World Health Organization(WHO)provisional guideline value of 0.01 mg L^(-1).Similarly,the Fe content varied from 0.05 to 10 mg L^(-1)averaging to 2.84 mg L^(-1).Samples of 55.17%contained a greater As concentration than0.01 mg L^(-1)and 18.97%greater than Bangladesh drinking water quality(BDWQ)standard of 0.05 mg L^(-1),respectively.Meanwhile,75.86%of samples contained a higher Fe concentration than the maximum Bangladesh permissible limit of 1 mg L^(-1).Health risk assessment indicated that girls are more vulnerable than boys are.The average hazard quotients(HQs)for As intake through drinking water were 6.01±17.85 and 7.41±22.03 for boys and girls,respectively,implying non-carcinogenic health risks to both genders.The HQs for Fe intake were less than threshold value of 1 indicating no health issues may arise from Fe intake alone.However,consumption of As and Fe may trigger health risks to students as indicated by the hazard index(HI),which was higher than 1.The average cancer risk(CR)values for both boys(0.0027±0.008)and girls(0.0033±0.0099)exceeded the threshold limit of 10-6-10-4,suggesting a possibility of lifetime cancer risks to the school-going children.Consequently,school authorities should find alternative ways to ensure safe drinking water for school-going children to avoid possible cancer and non-cancer health risks through consumption of As-poisoning water.

Covalently bonded ternary photocatalyst comprising MoSe_(2)/black phosphorus nanosheet/graphitic carbon nitride for efficient moxifloxacin degradation

Covalently bonded bridging between different semiconductors is a remarkable approach to improve the transfer of charge carriers at interfaces.In this study,we designed a ternary heterojunction(MBG)combining of molybdenum diselenide(Mo Se_(2)),black phosphorus nanosheets(Bpn)and graphitic carbon nitride(GCN).Among this MBG of Mo Se_(2)/Bpn/GCN,(i)the covalently bonded bridging effect between Bpn/GCN facilitates directional charge carrier transfer,meanwhile(ii)a Z-scheme heterojunction is formed between Mo Se_(2)/GCN to enhance the separation of photogenerated carriers.Furthermore,(iii)this composite exhibits an increased absorption for visible light.Using this MBG,photocatalytic degradation of over 98%of moxifloxacin is achieved within 20 min,with O_(2)·-confirmed as the primary photocatalytic active species.These findings provide novel insights into the construction of efficient heterojunction by covalently bonded bridging.

Mercury remediation potential of a mercury resistant strain Sphingopyxis sp.SE2 isolated from contaminated soil

A mercury resistant bacterial strain SE2 was isolated from contaminated soil.The 16 s rRNA gene sequencing confirms the strain as Sphingopyxis belongs to the Sphingomonadaceae family of the α-Proteobacteria group.The isolate showed high resistance to mercury with estimated concentrations of Hg that caused 50%reduction in growth（EC_（50）） of 5.97 and 6.22 mg/L and minimum inhibitory concentrations（MICs） of 32.19 and 34.95 mg/L in minimal and rich media,respectively.The qualitative detection of volatilized mercury and the presence of mercuric reductase enzyme proved that the strain SE2 can potentially remediate mercury.ICP-QQQ-MS analysis of the remaining mercury in experimental broths indicated that a maximum of 44%mercury was volatilized within 6 hr by live SE2 culture.Furthermore a small quantity（23%） of mercury was accumulated in live cell pellets.While no volatilization was caused by dead cells,sorption of mercury was confirmed.The mercuric reductase gene merA was amplified and sequenced.Homology was observed among the amino acid sequences of mercuric reductase enzyme of different organisms from a-Proteobacteria and ascomycota groups,

The interaction mechanisms of co-existing polybrominated diphenyl ethers and engineered nanoparticles in environmental waters: A critical review

This review focuses on the occurrence and interactions of engineered nanoparticles(ENPs)and brominated flame retardants(BFRs)such as polybrominated diphenyl ethers(PBDEs)in water systems and the generation of highly complex compounds in the environment.The release of ENPs and BFRs(e.g.PBDEs)to aquatic environments during their usage and disposal are summarised together with their key interaction mechanisms.The major interaction mechanisms including electrostatic,van derWaals,hydrophobic,molecular bridging and steric,hydrogen andπ-bonding,cation bridging and ligand exchange were identified.The presence of ENPs could influence the fate and behaviour of PBDEs through the interactions as well as induced reactions under certain conditions which increases the formation of complex compounds.The interaction leads to alteration of behaviour for PBDEs and their toxic effects to ecological receptors.The intermingled compound(ENPs-BFRs)would show different behaviour from the parental ENPs or BFRs,which are currently lack of investigation.This review provided insights on the interactions of ENPs and BFRs in artificial,environmental water systems and wastewater treatment plants(WWTPs),which are important for a comprehensive risk assessment.

Investigating Microplastics and Nanoplastics Released from a Rubber Band Used for Orthodontic Treatment with Improved Raman Imaging Algorithms

Most teenagers experience orthodontic treatment,but we do not know the possible adverse effect of the released microplastics and nanoplastics that are recently categorized as emerging contaminants.Herein,we test the rubber band that has been employed to improve the biting of teeth during the orthodontic process to confirm the release of microplastics and nanoplastics.We improve the characterization of microplastics and nanoplastics by(i)Raman imaging,to extract and map the signal from the scanning spectrum matrix or the hyperspectral matrix and to enhance the signal-to-noise ratio statistically.To effectively extract the signal,(ii)chemometrics such as principal component analysis(PCA)are explored to convert the hyperspectral matrix to an image with an increased certainty.The nonsupervised PCA is intentionally corrected,via(iii)the algebra-based algorithm,to further increase the certainty to image the microplastics and nanoplastics.Once the signal is weak,(iv)an additional algorithm of image reconstruction via deconvolution is developed to average the background noise and smooth the image.By doing so,we estimate that millions of microplastics and nanoplastics are released daily in potential from a rubber band applied in a teenager's mouth,which might be a big concern.Overall,our approach provides a suitable option to characterize the microplastics and nanoplastics from a complex background.

Towards advanced removal of organics in persulfate solution by heterogeneous iron-based catalyst:A review

Heterogeneous iron-based catalysts have drawn increasing attention in the advanced oxidation of persulfates due to their abundance in nature,the lack of secondary pollution to the environment,and their low cost over the last a few years.In this paper,the latest progress in the research on the activation of persulfate by heterogeneous iron-based catalysts is reviewed from two aspects,in terms of synthesized catalysts(Fe0,Fe_(2)O_(3),Fe_(3)O_(4),FeOOH)and natural iron ore catalysts(pyrite,magnetite,hematite,siderite,goethite,ferrohydrite,ilmenite and lepidocrocite)focusing on efforts made to improve the performance of catalysts.The advantages and disadvantages of the synthesized catalysts and natural iron ore were summarized.Particular interests were paid to the activation mechanisms in the catalyst/PS/pollutant system for removal of organic pollutants.Future research challenges in the context of field application were also discussed.

Can perfluorooctanoic acid be effectively degraded usingβ-PbO_(2)reactive electrochemical membrane?

Aqueous perfluorooctanoic acid(PFOA)elimination has raised significant concerns due to its persistence and bioaccumulation.Althoughβ-PbO_(2)plate anodes have shown efficient mineralization of PFOA,it remains unclear whether PFOA can be effectively degraded usingβ-PbO_(2)reactive electrochemical membrane(REM).Herein,we assessed the performance of Ti/SnO_(2)-Sb/La-PbO_(2)REM for PFOA removal and proposed a possible degradation mechanism.At a current density of 10 mA/cm2and a membrane flux of 8500(liters per square meter per hour,LMH),the degradation efficiency of 10 mg/L PFOA was merely8.8%,whereas the degradation efficiency of 0.1 mg/L PFOA increased to 96.6%.Although the porous structure of theβ-PbO_(2)REM provided numerous electroactive sites for PFOA,the generated oxygen bubbles in the pores could block the pore channels and adsorb PFOA molecules.These hindered the protonation process and significantly impeded the degradation of high-concentration PFOA.Quenching experiments indicated that·OH played dominant role in PFOA degradation.The electrical energy per order to remove 0.1 mg/L PFOA was merely 0.74 Wh/L,which was almost an order of magnitude lower than that of other anode materials.This study presents fresh opportunities for the electrochemical degradation of low-concentration PFOA usingβ-PbO_(2)REM.

Emerging contaminants:A One Health perspective

Environmental pollution is escalating due to rapid global development that often prioritizes human needs over planetary health.Despite global efforts to mitigate legacy pollutants,the continuous introduction of new substances remains a major threat to both people and the planet.In response,global initiatives are focusing on risk assessment and regulation of emerging contaminants,as demonstrated by the ongoing efforts to establish the UN’s Intergovernmental Science-Policy Panel on Chemicals,Waste,and Pollution Prevention.This review identifies the sources and impacts of emerging contaminants on planetary health,emphasizing the importance of adopting a One Health approach.Strategies for monitoring and addressing these pollutants are discussed,underscoring the need for robust and socially equitable environmental policies at both regional and international levels.Urgent actions are needed to transition toward sustainable pollution management practices to safeguard our planet for future generations.

Influence of soil physicochemical properties,particle size fractions and mineralogy on the leaching potentials of arsenic and antimony in abandoned mine soils

At abandoned mine sites,arsenic(As)-and antimony(Sb)-enriched soils are often disposed of through onsite burial or capping.In highly weathered mine sites,the mobility of As and Sb is typically controlled by iron(Fe)(III)/Fe(II)phases;thus,the suitability of such disposal methods and appropriate testing techniques are questionable.In the present study,leaching potentials of As and Sb were examined using the toxicity characteristic leaching procedure(TCLP),waste extraction test(WET),and WET-extended procedure(WET-EXT)at three abandoned mine site soils in Australia.The leached concentration of As regularly exceeded USEPA criteria(5 mg L^(-1)).The highest leached concentrations of As and Sb were observed in the finest particle size fraction(<0.053 mm)by WET-EXT(1040 mg L^(-1)for As and 21.10 mg L^(-1)for Sb)followed by WET(800 mg L^(-1)for As and 20.90 mg L^(-1)for Sb).The TCLP method resulted in the lowest concentrations of leached As(0.0009 mg L^(-1))and Sb(0.0003 mg L^(-1)).Crystalline and amorphous As-bearing Fe oxides were the main phases in the soils studied.However,the best correlations of leached As determined by TCLP(0.832),WET(0.944),and WET-EXT(0.961)were found with the non-specifically sorbed(NS1)As fraction.The mineralogical and sequential extraction data clearly indicate the dominant role of Fe geochemistry in controlling leachability of As and Sb.The TCLP method was unlikely to be suitable for assessing leachability,as it exhibited no relationship with leachable Fe and substantially lower leached As and Sb than the other two methods.Given the high to extremely high leachable As and Sb concentrations,most of the soil samples would not be recommended for placement in capping works,old shafts,or reduction systems(e.g.,collection in drainage basins).