长江沉积物中多环芳烃的污染特征、来源解析及生态风险评价

多环芳烃(Polycyclic aromatic hydrocarbons,PAHs)具有“三致”效应,其在环境中的污染特征及行为倍受关注.长江作为我国经济发展的重要纽带,其PAHs污染特征及来源亟需明晰.本研究以长江干流(攀枝花至南京)及主要支流为研究区域,分析了表层沉积物中19种PAHs的污染特征和来源,评估了PAHs类污染物的生态风险.结果表明,长江上游、中下游及主要支流江段沉积物中Σ19PAHs浓度分别为55.2～406.4ng·g^-1(均值(216.3±139.2) ng·g^-1)、48.0～500.4 ng·g^-1(均值(337.1±197.0) ng·g^-1)、90.1～429.8 ng·g^-1(均值(268.0±129.0) ng·g^-1).其中4环、5～6环类PAHs浓度范围分别占38.9%和39.9%.以三峡大坝为界,上游越靠近大坝沉积物中PAHs浓度越高,中下游越靠近长江口沉积物中PAHs浓度越高;近20年来长江干流沉积物中PAHs浓...     

青藏高原东北部地区表层土壤中全氟化合物的分布特征及来源解析

为探讨全氟化合物（PFASs）在偏远地区的赋存水平及其来源,采用超高效液相色谱-串联质谱法分析了青藏高原东北部地区18个点位表层土壤中12种PFASs含量水平和分布特征,并对其进行来源解析.结果表明,土壤中有11种PFASs检出,■范围为0.043～1.573 ng·g^-1,平均值为0.398 ng·g^-1,其中单体PFBA的含量最高(平均值为0.164 ng·g^-1),PFHxA含量最低(平均值为0.005 ng·g^-1),其他单体PFASs含量处于同一水平(平均值为0.011～0.057 ng·g^-1),短链PFASs是该区域PFASs的主要贡献者. PFASs空间分布整体表现为西和北部较高,东南较低,PFBA存在高山冷凝效应.主成分分析表明,青藏高原东北部区域土壤中PFASs主要来源于PFASs及其前体物大气传输至此发生的沉降和降解,少数地区受点源污染直接排放影响,金属和矿产等工业生产和人类活动是其主要来源.     

太原市耕地土壤PAHs的含量、分布、源解析与风险评价

为研究太原市耕地土壤中多环芳烃(PAHs)的含量、空间分布特征、来源与健康风险,采集了太原市22个耕地土壤样本,通过GC-MS分析土壤中PAHs的含量,使用诊断比率法与正定矩阵因子分解(PMF)模型分析土壤PAHs的来源,使用增量终生致癌风险模型分析土壤的健康风险.结果表明,太原市耕地土壤(干重)中∑₂₁PAHs和∑₁₆PAHs含量平均值分别为934.6 ng·g^-1和787.7 ng·g^-1,土壤中PAHs含量低于GB 15168-2018规定的农用地土壤污染风险筛选值.工业区、丘陵区和污灌区分别有约60%、 13%和33%的样点的PAHs含量超过了1 000 ng·g^-1.空间分布显示耕地土壤PAHs含量高的区域集中在工业区;诊断比率显示煤炭和生物质燃烧与交通排放是太原市耕地土壤中PAHs污染的主要来源;PMF模型模拟结果表明,耕地土壤中PAHs的来源和贡献率为煤炭和生物质燃烧源(59%)、交通源(22%)和炼焦源(19%).风险评价结果表明太原市耕地土壤普遍具有高致癌风险...     

雷州半岛南部典型农用地土壤-作物的有机氯农药残留特征和健康风险评价

利用气相色谱-质谱法（GC-MS）测定雷州半岛南部典型农用地土壤-作物有机氯农药（OCPs）的残留含量,探究8种作物对有机氯农药的生物富集特征,并进行人体健康风险评价.结果表明,10种OCPs均有不同程度地检出,其中六六六（HCHs）和七氯是研究区主要污染物,在土壤中残留含量分别为23.83～111.51 ng·g^-1和11.01～25.97 ng·g^-1,在作物中分别为7.54～61.28 ng·g^-1和3.96～30.97 ng·g^-1,少部分土壤和作物样品中该两类OCPs存在超标情况.有87.50%土壤样品α-HCH/γ-HCH小于1,且β-HCH/α-HCH大于1,表明HCHs可能来源于近期林丹的使用和历史施用残留污染,而七氯推测主要来源于地下虫害和白蚁防治药剂的施用.不同作物对OCPs的富集能力差异较大,蔬菜类作物的生物富集能力较强,水果类较弱,且鳞茎类蔬菜（韭菜）明显强于其他蔬菜类别.人体健康风险评价表明,土壤与作物中OCPs对区域内人群基本不会造成明显的健康风险.但韭菜和辣椒作物复合污...     

洛阳地区碳质组分季节特征及来源解析：棕碳的重要贡献

为探究洛阳地区碳质气溶胶尤其是棕碳的季节、污染特征及其来源解析,于2018～2019年的四季共采集到98个样品,并分析了碳质气溶胶浓度特征和光学特性.4个季节ρ[有机碳(OC)]和ρ[元素碳(EC)]介于(7.04±1.82)～(23.81±8.68)μg·m^-3和(2.96±1.4)～(13.41±7.91)μg·m^-3,呈现冬高夏低的季节变化趋势;与2015年相比,碳质组分的占比升高了8.33%～141.03%,二次有机气溶胶占比(SOC/OC)升高了0.77%～63.14%.碳质气溶胶光吸收截面(MAC)值与碳质组分的浓度呈现出不同的季节变化,秋季(7.67m²·g^-1)>冬季(5.65 m²·g^-1)>春季(5.13m²·g^-1)>夏季(3.84m²·g^-1),445 nm处的MAC值(3.84～7.67m²·g^...     

Co@AC的包埋固定及其对农药阿特拉津的去除机制

阿特拉津作为一种常用的除草剂,已被国际癌症研究机构列为具有致癌风险的2B组类别,这意味着阿特拉津对人类和生态环境有极大的影响.为实现对水中阿特拉津的高效去除,该研究采用包埋固定化技术(EI)将钴改性活性炭粉末(Co@AC)进行包埋固定,制备新型环境功能材料“EI-Co@AC”.当海藻酸钠为2.5%、氯化钙为4.0%、Co@AC为1.0%、膨润土为2.0%时,制备的EI-Co@AC小球具有最优的机械强度和传质性能,且小球内部具有较高的孔隙率、致密的网状结构以及大量的官能团.当EI-Co@AC投加量为16 g·L^-1、溶液pH为3.0、温度为25℃时,10 h内小球对50 mL、5.0 mg·L^-1的阿特拉津去除率可达92.3%,机理研究表明小球对阿特拉津的去除主要是化学吸附和多分子层吸附.此外,经过5次重复实验后,EI-Co@AC对阿特拉津的去除率仍在75%以上,且小球结构完整,表明EI-Co@AC具有良好的重复使用性能.综上,该研究制备的EI-Co@AC是一种无毒、经济、可重复利用的环境功能材料,可用于水环境中的阿特拉津及其他有机污染物的去除...     

一株类节杆菌协同还原六价铬和降解阿特拉津的研究

六价铬(Cr(Ⅵ))和阿特拉津复合污染在环境中普遍存在,给生态安全和人类健康带来严重危害.为了实现对Cr(Ⅵ)和阿特拉津复合污染的协同修复,本研究在复合污染场地筛选出一株同时具有阿特拉津降解能力和Cr(Ⅵ)还原能力的类节杆菌Paenarthrobacter sp. AT.在单一污染条件下,菌株AT可以在24 h内将初始浓度为400 mg·L^-1的阿特拉津完全降解,将初始浓度为10 mg·L^-1的Cr(VI)完全还原;同时,菌株还具有很强的阿特拉津和Cr(Ⅵ)耐受性.菌株AT被鉴定含有trz N、atz B和atz C阿特拉津降解功能基因,将阿特拉津降解为无毒终产物氰尿酸,同时生成乙胺和异丙胺两种代谢副产物,其中,乙胺在溶液中持续积累,而异丙胺则短暂积累再被降解.在复合污染条件下,菌株AT对初始浓度为200 mg·L^-1阿特拉津的降解率为100%,对初始浓度为10 mg·L^-1的Cr(Ⅵ)的还原率为44%.本研究证实了微生物可以利用有机污染物作为氮源实现对重金属的转化,为开发绿色低碳微生物修复技术提供...     

广西十万大山背景点PM2.5中非极性有机气溶胶组成及来源解析

大气细颗粒物(PM_2.5)中的非极性化合物包括多环芳烃（PAHs）和正构烷烃（n-alkanes）等,通常用于识别污染来源,且对人体健康和环境有很重要的影响.为探究广西背景点PM_2.5中非极性有机气溶胶的污染特征及来源,于2017年11月至2018年10月,对野外采集的PM_2.5样品分析了其中17种多环芳烃和20种正构烷烃.结果表明,多环芳烃和正构烷烃全年的平均值分别为（4.28±4.25）ng·m^-3和（13.7±14.72）ng·m^-3;季节变化规律均是：冬季[（7.86±5.19）ng·m^-3和（27.51±16.9）ng·m^-3]>春季[（2.73±1.76）ng·m^-3和（7.64±4.71）ng·m^-3]>秋季[（2.34±1.45）ng·m^-3和（7.01±4.55）ng·m^-3]>夏季[（1.91±1.67）ng·...     

铁掺杂氯氧化铋光芬顿催化降解水中阿特拉津的性能与机理研究

采用溶剂热反应制备了分级微球结构的铁掺杂氯氧化铋(Fe-BiOCl),并用于光芬顿降解阿特拉津(Atrazine,ATZ).结合多因素实验,系统地分析了以Fe-BiOCl为催化剂构建的光芬顿体系氧化降解阿特拉津的性能与机理.结果表明,当催化剂用量为0.2 g·L^-1、污染物浓度为20 mg·L^-1、H₂O₂浓度为6.4 mmol·L^-1时,Fe-BiOCl-2催化剂在120 min内降解阿特拉津的效率约为99.98%,且在较宽pH范围(3.04～6.02)内保持优异的降解效率.通过自由基猝灭实验和电子顺磁共振(EPR)测试发现,在光芬顿体系中羟基自由基(·OH)和超氧自由基(·O₂^-)是反应的主要活性物种.此外,通过超高效液相色谱测定降解过程中的中间产物,提出了可能的降解路径和转化机理.     

山西野生连翘生长地土壤PAHs污染特征及风险评价

山西是我国道地药材连翘的主产地之一,为探明连翘生长区土壤的安全性,在连翘成熟期从山西东南部野生连翘生长区采集了70个表层(0～25 cm)土壤样品,采用化学提取和气相色谱-质谱联用仪(GC-MS)分析方法,探讨了样品中16种多环芳烃(PAHs)的含量与组成特征;利用比值法确定了PAHs的来源,并通过计算污染土壤PAHs的苯并[a]芘(Ba P)等效毒性当量评估了其潜在风险．结果表明,样点土壤PAHs总量(Σ16PAHs)的平均值为1.85μg·g^-1,3环PAHs的占比最高(平均值为76.7%),其中,3环的菲(Phe)和蒽(Ant)的样点检出率为100%;该生长区PAHs主要来源于空气传输与沉降的煤、生物质燃烧和车辆排放的污染物;所有样点土壤Σ16PAHs均达到了Maliszewska-Kordybach提出的农用土壤污染水平(Σ16PAHs含量>0.2μg·g^-1),41.4%的样点达到了重度污染水平(Σ16PAHs含量>1.0μg·g^-1),其中,10.0%的样点土壤Ba P的含量大于我国农用土壤筛选值...     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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