南小河沟流域地表水和地下水的稳定同位素和水化学特征及其指示意义

南小河沟流域为典型的黄土高原沟壑区,本文分析了该流域地表水和地下水的氢氧稳定同位素和水化学特征,揭示了地表水与地下水之间的相互关系.结果表明,大气降水的δD和δ~(18)O值呈现春夏高,秋冬低的季节变化特征.水库水的δD和δ~(18)O值的季节性变化规律呈现夏秋高、冬春低的特征.地下水的δD和δ~(18)O值季节性变化规律相对不显著.流域内地表水和地下水水化学类型主要为Na·Mg-HCO_3型.地表水和地下水电导率的季节性变化规律均呈现冬季高、夏季低的特点.当地大气降水和深层地下水可能是南小河沟流域内地表水(水库水、沟道水)和泉水的主要补给来源.流域内的常流泉可能主要由深层地下水补给,而季节泉,例如,董庄沟和杨家沟的源头泉则可能是由深层地下水和当地大气降水共同补给.     

闪电河流域“三水”氢氧同位素特征及水体转换分析

通过采集闪电河流域2020年2月至2022年2月的降水与2021年的丰(8月)和枯(10月)水期的地表水和地下水,运用稳定同位素技术,对流域“三水”的氢氧稳定同位素进行时空变化分析,探讨水体同位素与环境因子的关系,结合HYSPLIT模型追踪大气水汽来源,利用端元混合模型揭示水体转换关系.结果发现,当地降水线的斜率和截距均小于当地大气降水线,水汽主要来自西风水汽、极地气团和东亚季风环流,降水同位素有显著的温度效应;时间上,地表水与地下水同位素在季节变化上均表现出枯水期较丰水期更富集,地表水与地下水d-excess值均低于全球平均值,显现出当地强烈的蒸发作用;空间上,地表水δ¹⁸O值丰枯季节在空间上具有相同的变化特征,呈现上游至下游逐渐富集,地下水δ¹⁸O高值区空间分布不均,地下水δ¹⁸O值随埋深的增加更加贫化;地下水水线斜率最高在丰水期为7.87,与当地大气降水线和地表水水线斜率十分接近,表明丰水期“三水”存在复杂的水力联系.研究区在丰水期地表水主要接受降水的补给,其次是接受地下水的径流补给.研究结果有助于明确闪电河流域同...     

西北干寒区冰雪融水氢氧同位素水文地质意义

该文根据Dansgoard氘盈余理论,对中国西北干寒地区(甘肃祁连山-黑河流域、新疆塔什库尔干河流域、青海阿尼玛卿山和西藏羊八井)4个典型研究区大气降水、地表水、冰雪融水、地下水的氢氧同位素组成进行了研究对比;发现冰雪融水和部分地下水的δ~2H-δ~(18)O信号均位于地方降水线和全球降水线左上方的罕见现象;进一步研究证明了δ~(18)O、δ~2H和d值在干寒、缺水而有现代冰川分布区研究天然水循环过程有奇特的效果,可以识别地下水是由冰雪融水补给的还是由大气降水补给的,甚至可以区分不同含水层地下水的补给来源,同时分析δ~2H-δ~(18)O信号和氘盈余资料,对判断有冰川、积雪存在地区地下水的补给来源和循环演化具有普遍的水文地质意义和应用价值。     

重庆地区大气场降水中氢氧同位素变化特征及与大气环流的关系

根据2015年4~10月重庆地区61场降水稳定同位素资料与相关气象资料,分析了不同时间尺度下重庆大气降水中氢氧同位素(δD、δ~(18)O)、过量氘(d)的变化特征以及它们与降水量、温度及厄尔尼诺/拉尼娜和南方涛动(ENSO)的关系.结果表明:1研究区大气降水线方程为:δD=8.28δ~(18)O+12.34(r=0.99,n=61),其斜率和截距与中国东部季风区的多处南方地区大气降水线方程的斜率和截距相似.2研究区大气降水中氢氧同位素和d均出现夏半年低、冬半年高的季节变化,影响重庆降水中氢氧同位素变化的主要原因为不同季节降水的水汽来源及气团性质的差异.3监测时段内研究区大气降水中δ~(18)O与温度、降水量相关性不显著(r=0.03;r=0.12),但却敏感响应了大气环流过程,表现出与ENSO正相关.大气降水中δ~(18)O和过量氘(d)清晰记录了2014~2015年LaNia和ElNio的转换过程.ElNio期间研究区域大气降水中δ~(18)O和d明显偏重;而在LaNia期间,δ~(18)O和d偏轻.     

长江源多年冻土区地下水氢氧稳定同位素特征及其影响因素

基于长江源区冬克玛底流域2017年6～9月采集的84个地下水样品,分析了地下水稳定同位素特征及其影响因素,讨论了地下水的补给来源.结果表明,研究区多年冻土区地下水δ~(18)O的变化范围为-15. 3‰～-12. 5‰,平均值为-14. 0‰;δD的变化范围为-108. 9‰～-91. 7‰,平均值为-100. 2‰,与当地大气降水相比,地下水较为富集重同位素;地下水线(LG)的斜率和截距均低于全球和局地大气降水线(GMWL和LMWL),表明地下水在接受降水的补给后经历了不同程度的蒸发作用;地下水氘盈余(d-excess)变化范围为4. 9‰～25. 0‰,平均值为11. 6‰,低于大气降水平均氘盈余值;地下水同位素与降水量存在显著的负相关关系,表明大气降水对地下水具有重要的补给作用;不同时期影响地下水同位素的组成和变化因素有所不同,在冻土的冻融前期(气温上升阶段),由于冻土活动层较薄,地下水受气温影响显著.虽然后期气温降低,但冻土活动层厚度依然在增加,此时地下水在土壤中滞留的时间的增加是地下水同位素富集的一个重要因素.结合流域的地形特点、地下水同位素特征及其影响因素,推断降水是地下水的主要补给来源.研究结果能够为长江源多年冻土区的水循环过程提供科学依据.     

江苏洋口港地区地下水的环境同位素组成及其形成演化研究

江苏洋口港地区是江苏沿海开发重点建设的深水港区,水质优良的地下水是港区经济社会发展的重要基础.本研究利用近期获得的钻孔剖面地层对比数据资料,沿水文径流剖面分层采集水样,通过识别地表水、各含水层地下水的环境同位素(δD、δ~(18)O、~3H、~(14)C)组成指纹特征,以揭示研究区地下水的形成演化规律.结果表明,研究区浅层地下水主要来源于现代大气降水的入渗补给,大气降水在补给地下水过程中经历了明显的蒸发过程;研究区深层地下水的放射性~(14)C年龄主要为15000~26000 a,其稳定同位素δ~(18)O、δD值比现代降水低,是晚更新世末次冰期(大理冰期)的盛冰期降水入渗补给.地下水含水层的氘、氧、碳同位素分布具有明显的呈层性,随着地下水埋藏深度增加,地下水中的δD、δ~(18)O值呈下降趋势.浅层地下水与地表水水力联系紧密,可更新能力较强;深层地下水径流缓慢,总体上处于封闭-半封闭状态,可更新能力弱.江苏沿海平原天然地下水流动是自晚更新世末期以来,伴随着冰退、海平面上升而调整到目前的模式.末次盛冰期以来的自然地理及地质发展史,决定着研究区第四系地下水流系统的演变格局,现代人类活动加强了浅层与深层地下水之间的水力联系.研究在高强度开发地下水条件下的区域水文循环特征,可为沿海地区地下水演变机理和调控研究提供技术支持.     

关中平原降水氢氧稳定同位素特征及其水汽来源

为探究关中平原降水氢氧稳定同位素特征及其水汽来源,本研究选取关中腹地的杨凌站点次降水为研究对象,利用当地2015～2018年间的98场次降水样品及同期气象资料,分析该地区降水氢氧稳定同位素(δ~2H、δ~(18)O和δ~(17)O)组成特征及其影响因素,建立当地大气降水线和三氧同位素大气降水线方程,并利用δ~(18)O、d-excess和~(17)O-excess指标尝试探讨当地可能存在的降水水汽来源,定量描述海洋和内陆源水汽对区域降水的贡献.结果表明,杨凌地区降水氢氧稳定同位素存在明显的季节性变化,同位素组成雨季(5～10月)贫化,旱季(11月～次年4月)富集;当地大气降水线的斜率和截距分别为7.7和9.1,说明研究区降水受到一定程度的蒸发分馏影响;三氧同位素大气降水线斜率为0.528,介于海水平衡分馏斜率(0.529)与水汽扩散斜率(0.518)之间,表明研究区处于海洋气团向内陆干旱区迁移的路径上.综合分析δ~(18)O、d-excess和~(17)O-excess,发现研究区降水受到来自东南季风的暖湿气团和来自西风的干冷气团的共同贡献,其中约有55%～79%的降水水汽来源于海洋,主要集中于6～8月; 21%～45%的水汽来源于内陆和局地蒸发,主要集中于10月～次年4月. 5月和9月降水水汽来源复杂,可能受海洋水汽和内陆水汽的共同补给.     

用氯和氢氧同位素揭示洋戴河平原地下水的形成演化规律

通过分析地表水和地下水中氯离子浓度和δD、δ¹⁸O值的空间分布特征,揭示了秦皇岛洋戴河平原地下水的形成演化规律.结果发现,洋戴河平原地表河水来源于中上游水库水和大气降水的混合,且河水沿程受到δD、δ¹⁸O值、氯离子浓度更低的支流或灌渠水补给,从而使δD、δ¹⁸O值、氯离子浓度呈现沿程逐渐降低的现象.山前丘陵区地下水主要接受大气降水的直接补给,洪积扇及山麓地带地下水受到了一定的蒸发作用影响,除了接受丘陵区地下水的侧向补给外,洋河附近地下水还受到洋河水库水的混合.研究区西部咸水带的地下水由上游地下水和大泥河地热咸水混合而成,地热咸水的混合比率约为13%,而东部咸水带的地下水由上游地下水、本地污水和地热咸水混合而成,地热咸水的混合比率不超过9%.在海水入侵区,地下水主要由本区地下淡水和海水(海水混合比率不超过10%)混合而成,并且受到了不同程度的地表水或农田灌溉水的补给,其中,浦河一带是地表水或灌溉水补给较为明显的地段.     

南太行山山前平原地下水和地表水氢氧同位素组成及环境意义

借助氢氧同位素和水化学方法对南太行山山前平原地下水补给运移规律进行研究,阐明人类活动对地下水的影响过程。研究结果表明:(1)区内不同水体δD、δ~(18)O、氘盈余值(d-excess)和氚同位素(T)值差异明显,深层地下水均值分别为-74.0‰、-9.4‰、1.5‰和8.73TU,浅层地下水均值分别为-72.1‰、-8.8‰、-1.9‰和17.46TU,河水均值分别为-71.3‰、-8.9‰、-0.4‰和18.60TU,工业废水均值分别为-68.3‰、-7.2‰、-10.7‰和21.11TU;(2)补给区深层地下水δD、δ~(18)O和d-excess年均值分别为-68.08‰、-9.24‰和5.84‰,径流区深层地下水δD、δ~(18)O和d-excess年均值分别为-62.30‰、-8.50‰和5.66‰,排泄区深层地下水δD、δ~(18)O和d-excess年均值分别为-75.14‰、-10.26‰和6.94‰;(3)深层地下水补给源包括大气降水和河水,受污染河水通过断层导水裂隙带补给深层地下水。浅层地下水补给源包括大气降水和河水,受污染河水通过河流侧渗方式补给浅层地下水;(4)受河水影响的深层地下水氘盈余值变低,T含量升高,因此结合氘盈余值与T含量可以很好地识别区内深层地下水污染过程。     

拉萨河夏季氢氧同位素空间分布特征及分析

稳定同位素示踪技术是河流水文过程研究的重要方式,可以用来判定河流补给的来源、研究河流与其它水体相互作用、示踪水文循环过程等。本文采用TC/EA-IRMS分析法对拉萨河水体的氢氧同位素进行测定,分析了δD和δ~(18)O的含量及空间分布特征,并分析了拉萨河的同位素效应,包括与大气降水氢氧同位素的关系、氢氧同位素的沿程变化特征、氘过量参数沿程变化、高程效应及大陆效应等。结果表明:拉萨河水体受补给来源、大陆效应、高程效应等因素影响,其水体氢氧同位素也呈现出不同的特征。整体而言,拉萨河水体δD和δ~(18)O随沿程距离增大而下降;δD和δ~(18)O均分布在全球大气降水线和青藏高原东部大气降水线附近,表明大气降水是拉萨河流域主要的补给来源;拉萨河水体的氘过剩参数均大于10‰,且远超全球大气降水线对应的氘过剩参数,说明拉萨河可能存在接受氢氧同位素较贫化的冰雪融水补给。     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

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.