青海湖江西沟2号遗址炭屑浓度反映的环境变化与人类活动

通过对JXG2人类遗址的自然条件、人类活动和不同粒级的炭屑浓度变化分析,研究了全新世炭屑颗粒大小与人类活动的关系。研究结果表明:(1)全新世早期(10.4~9 ka BP),细粒(10~50μm)和中粒(125~50μm)炭屑浓度逐渐增加;而在全新世大暖期各个粒径的炭屑含量在整个全新世总体较低;5 kaBP之后,降水减少,气温波动大,随着气温的波动,中粒炭屑浓度与之很好地对应。因此中粒(125~50μm)炭屑浓度的变化能较好地与各个时段的自然条件相对应。(2)全新世早期,人类活动逐渐增加,细粒(10~50μm)和中粒(125~50μm)炭屑浓度逐渐增加;人类活动最为频繁的7~6 ka BP,中粒和粗粒(125μm)的炭屑浓度增高;4.5 ka BP前后新石器文化活跃期,中粒炭屑浓度较为明显地反映了人类活动。     

甘肃合水地区全新世以来土壤剖面黑碳记录及其气候变化

针对甘肃合水马家村(MJC)全新世黄土剖面进行野外采样,分析磁化率和黑碳(焦炭和烟炱)等古气候指标,试图探讨黄土高原北部全新世以来生物质燃烧特征以及自然生态环境演变过程,结果表明:末次冰期和全新世早期(11500—8500 a BP)气候寒冷而干旱,区域野火事件时而发生,植被生物量是此阶段野火发生与蔓延的限制因素;距今8000年以来,黑碳和炭屑浓度整体呈现下降趋势。由于季节性降水增多从而抑制大范围火灾发生几率。然而,8000—7000 a BP和3500—2500 a BP野火频率明显上升,这可能与仰韶时期老官台文化和寺洼文化时期的古人类放火烧荒和开垦农田等活动有关;全新世晚期(3100 a BP至今)气候进一步干旱,生物质燃烧增强与人口增加和人类土地利用水平密切相关,其中1500—1000 a BP出现一次较为明显的峰值,这可能与隋唐以来该区农耕活动加强有关。可见,近2000年以来黄土高原北部地区生物质燃烧特征受到气候和人类活动复合驱动所控制。     

甘青地区定西巉口齐家文化时期的古气候环境

甘青地区从新石器时代以来黄河流域上游各个支流分布着大量的古文化遗址。我们首次在甘青地区定西巉口5 200～3 700 cal a BP时期地层中发现了齐家文化遗存。通过对瓷器残片的初步分析,认为该地区的古文化代表了原始文明的封闭性,但落后的生产方式也受到当时较发达主流文化中先进生产技术的影响,表现出丝绸之路古文明的传承和交流。本文对粒度、碳酸盐含量、TOC含量,以及有机组分、元素含量等古环境指标的综合分析,结合5个AMS ~(14)C年代值建立的深度-年代模式,对巉口剖面末次冰消期以来的古环境进行重建。结果表明,～13 300 cal a BP气候干冷; 13 300～11 200 cal a BP气候干旱、较少陆生植物; 11 200～5 200 cal a BP气候较为适宜,陆生植被发育,木本植物数量增加,为半干旱森林-草原环境; 5 200～3 700 cal a BP期间草本和木本植物急剧减少,气候干旱程度增加; 3 700～2 200 cal a BP气候处于干旱-半干旱状态,以疏林草原植被为主; 2 200 cal a BP以来该地区人类活动加强。巉口齐家文化遗址位于5 200～3 700 cal a BP期间的河漫滩沉积环境中,齐家文化的兴起和衰落处于气候干冷、陆生植被极不发育时期,人们主要在靠近河道的漫滩一级阶地上择水而居。     

中晚全新世六盘山流域土壤侵蚀的湖泊沉积记录

流域土壤侵蚀是流域水文—气候—生态的集中表现之一,对生态、环境等有着重大影响,重建过去流域土壤侵蚀强度对理解区域人类活动具有重要意义.本文选取黄土高原西南部高山湖泊——六盘山天池沉积岩芯为研究对象,基于XRF岩芯元素数据分析,结合可靠的AMS 14C年代序列,重建了中晚全新世以来六盘山流域土壤侵蚀强度变化记录.结果显示:5570?—?1600 cal BP,流域土壤侵蚀整体较强,侵蚀强度逐渐减弱,其主要受控于降水变化,也受植被覆盖等因素的影响;随着晚全新世气候逐渐变干,1600 cal BP之后的侵蚀强度整体弱于前一时期,此时段由于人类活动的显著影响,加剧了流域的土壤侵蚀.太阳辐射可能是研究区土壤侵蚀强度变化的初始驱动力,ENSO通过驱动亚洲季风变化影响区域降水,进而直接影响流域土壤侵蚀的强度变化.     

地球化学元素记录的沂河中游16.9~4.7 ka BP气候变化

临沂商品城剖面记录了末次冰消期至中全新世沂河中游的气候环境变化,其地球化学元素的古环境意义显著。分析表明末次冰消期至中全新世沂河中游的古气候环境经历了5个阶段:(1)16866～13630cal a B.P.气候回暖但仍以冷湿为主;(2)13630～10440cal a B.P.气候变冷变干,并记录到了YD气候事件;(3)10440～8670cal a B.P.暖湿气候显著;(4)8670～6420cal a B.P.冷暖波动仍以暖湿为主;(5)6420～4698cal a B.P.稳定的暖干气候环境。     

长江、黄河流域全新世古洪水事件对比研究

本文通过调研长江、黄河流域全新世古洪水研究相关文献,开展了两大流域全新世古 洪水发生频次空间对比研究。现有资料表明,两大流域全新世古洪水在6000 a BP 以前发生较 少;6000—4000 a BP 古洪水频次上升,在4000 a BP、3000 a BP 前后均出现一个洪水多灾期; 3000 a BP—1000 a BP 两大流域古洪水记录频次呈递减趋势;1000 a BP 以来,两大流域整体上 表现为递增的趋势,而值得注意的是1000 a BP 后,两大流域古洪水记录频次呈现出反相位变化 的趋势。与太阳活动记录对比,发现两个流域洪水发生均与太阳活动相关,但是两个流域洪水 发生对太阳活动的响应相反,长江流域在太阳活动较弱的时期,洪水多发,而黄河流域在太阳 活动较强的时期,洪水多发。     

泾河中游将军村全新世剖面中钾素的地球化学特征及古气候意义

通过对泾河中游将军村全新世黄土地层中钾素、低频质量磁化率、频率磁化率、Rb/Sr与年代学综合分析,着重探讨了黄土中钾素的地球化学特征及其所揭示的古气候变化。研究表明：（1）速效钾、缓效钾具有很明显的古气候指示意义,可作为衡量东亚夏季风强弱的一种敏感参数或代用指标,并且对微弱的古气侯波动反映更灵敏。（2）近万年来将军村剖面所经历的古气候变化特征：早全新世（11.20—8.05 ka BP）气候逐渐趋于相对暖湿,但气候冷干/暖湿波动频繁交替;中全新世（8.05—3.10 ka BP）气候适宜;晚全新世前期（3.10—2.00 ka BP）气候偏凉干;晚全新世后期（2.00 ka BP—至今）气候再度转为偏暖湿。（3）将军村剖面全新世气候适宜期是渐变形成的,但大暖期却在约3.10 ka BP时以气候突变形式终结。     

梵净山世界自然遗产地全新世以来的古气候变化

全新世是距离人类最近的间冰期,其气候变化受到广大学者的关注。中国东亚季风区全新世以来的气候变化对于揭示全球气候变化的驱动机制、预测未来气候变化具有重要意义。本研究通过对地处西南季风与东南季风过渡区的贵州梵净山世界自然遗产地九龙池湿地冰蚀湖相沉积JL15柱芯样品剖面孢粉、烧失量、碳氮含量的分析,结合加速器质谱(AMS)14C测年结果,建立了该地区全新世以来的古环境演变序列。结果表明,梵净山地区全新世以来经历了冷干期、过渡期、暖湿期、暖干期和冷干期5个阶段,其中第Ⅲ阶段(8. 0～4. 6 cal ka BP)可能为全新世大暖期的鼎盛期。总体而言,全新世早中期由干冷转为暖湿,后期气候逐渐转为寒冷干燥,但存在变暖的趋势。JL15柱芯共记录了全新世以来5次较明显的降温事件:2. 6、3. 4、4. 2、9. 4和10. 0 cal ka BP,其中与北大西洋浮冰碎屑(IRD)事件有联系的是4. 2和9. 4 ka事件。与西南地区其他气候记录相似,梵净山JL15柱芯所反映的冷事件与IRD事件存在一定联系,但也存在差异性,这可能与全球气候变化驱动机制的复杂性有关,需要后续研究的进一步探讨。     

江汉平原湖相沉积物元素地球化学记录揭示的12.8 cal. ka BP 以来气候环境演变

以江汉平原JZ-2010湖相沉积剖面为研究对象,AMS ¹⁴C年代数据为框架,通过对湖相沉积物的元素地球化学记录进行综合分析与对比研究,重建了江汉平原冰消期末至全新世以来的古环境演化过程,并探讨了区域气候变化的可能驱动因素。结果表明：12.8—9.1 cal. ka BP,研究区气候总体上温凉偏干,但有逐渐向暖湿变化的趋势;9.1—6.3 cal. ka BP,气候温暖湿润,水热配置均匀;6.3—4.4 cal. ka BP,气候前期较为暖湿,后期有逐渐向干旱转变的趋势;4.4—1.3 cal. ka BP,气候经历4.2 ka冷干事件后逐渐向温暖湿润转变。硅铝率、CIA和Rb/Sr指标的变化趋势与太阳辐射量、北大西洋赤铁矿染色颗粒及底栖有孔虫壳体δ¹³C记录之间存在较好的对应关系,揭示出江汉平原12.8 cal. ka BP以来的气候变化受控于北大西洋深水流的变化,同时,中晚全新世以来气候变化趋势与北半球夏季太阳辐射变化趋势较为吻合,太阳辐射主要通过季风环流间接影响区域气候变化。     

威海地区中全新世聚落遗址时空分布及驱动因素

本文通过ArcMap软件对威海地区中全新世聚落遗址的高程、坡度、坡向、濒河度等指标进行深入研究,分析该时期研究区的聚落遗址分布规律,结合中全新世研究区的环境变化背景,讨论威海地区中全新世聚落遗址时空分布及驱动因素.研究表明:(1)威海地区中全新世聚落遗址文化序列为后李文化 — 大汶口文化 — 龙山文化 — 岳石文化,与山东新石器文化序列相比缺少北辛文化,遗址数量随时间推移大致呈先增后减再增的右倾斜"N"型.(2)威海地区中全新世聚落遗址在高程、坡度、坡向及濒河度等存在一定的规律性.聚落遗址多集中分布于高程>30 m坡度在0° —4°的平缓地区,从坡向上看,聚落遗址大多分布在东南、南、西南方向的阳坡,占遗址总数的58.1％,从濒河度上看,聚落遗址都在距河流<1.5 km的范围.(3)威海地区在中全新世前期开始出现人类活动(后李文化,8.5—7.5 ka BP),随着中全新世大暖期的到来,气候总体进入温暖期,整体较为温和,优越的自然条件促进了大汶口文化(6.3—4.6 ka BP),发生在5.0—4.0 ka BP的海侵事件可能是导致大汶口文化衰减的主要原因,并限制了后期龙山文化(4.6—4.0 ka BP)的发展,与其他研究不同的是,尽管4.0 ka BP以后,气候开始恶化,但是海平面下降为威海地区人类发展提供了更为宽阔的空间和肥沃的土壤,而且古河道为古人类生存和生活提供了坚实的保障,由此优越的自然条件促进了岳石文化(4.0—3.5 ka BP)的发展.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

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.