有机物料影响下土壤溶液中镉形态及其有效性研究

研究了盆载种稻条件下，有机物料对土壤水溶性镉、易解离太镉和可解离态锯的含量变化及其有效性的影响，结果表明，不添加外源镉时，分蘖期猪烘和泥炭均降低了水溶性镉总量，水溶性镉的３４％～７７％可被阳离子交换树脂解离，８７％以上可被螯合树脂解离，到成熟期水生镉的解离度升高，水溶性镉总量与ＤＯＣ和ＰＨ的变化趋势相反，添加外源镉时分蘖期猪烘和泥炭均降低水溶性 量，成熟期水溶性镉总量与ＤＯＣ的变化呈相反趋势，在不     

三种不同生态型竹种植硅体碳汇比较研究

为研究不同生态型竹种生态系统中植硅体碳的分布和积累特征,论文选取了浙江省境内发育于同一土壤类型的3种竹林生态系统,分别采集其不同年龄的地上部分（叶、枝、秆）和现存凋落物以及不同深度的土样,分析各样品的植硅体含量、植硅体碳含量和硅含量。结果表明：1）3种不同生态型竹种器官中植硅体和植硅体碳积累和分布特征均为叶>枝>秆,土壤中植硅体和植硅体碳储量达到最大,且随土层深度增加植硅体碳储量有增加趋势;2）通过3种竹种植硅体碳储量比较,散生竹高节竹生态系统植硅体储量最高,丛生竹绿竹和混生竹茶秆竹植硅体碳储量相近;3）根据3种竹种在全国的分布面积估算,茶秆竹生态系统总固碳能力略大于绿竹,而远远高于高节竹。     

Potential of weed species applied to remediation of soils contaminated with heavy metals

To screen out a series of ideal plants that can effectively remedy contaminated soils by heavy metals is the main groundwork of phytoremediation engineering and the first step of its commercial application on a large scale. In this study, accumulation and endurance of 45 weed species in ]6 families from an agricultural site were in situ examined by using the pot-culture field experiment, and the remediation potential of some weed species with high accumulation of heavy metals was assayed. The results showed that Solanum nigrum and Conyza canadensis can not only accumulate high concentration of Cd, but also strongly endure to single Cd and Cd-Pb-Cu-Zn combined pollution. Thus 2 weed species can be regarded as good hyperaccumulators for the remediation of Cd-contaminated soils. Although there were high Cd-accumulation in Artemigia selengensis, Znula britannica and Cephalanoplos setosum, their biomass was adversely affected due to action of heavy metals in the soils. If the problem of low endurance to heavy metals can be solved by a reinforcer, 3 weed species can be perhaps applied commercially.     

黄土高原典型林木根际土壤微生物群落结构与功能特征及其环境指示意义

通过研究黄土高原典型林木根际土壤微生物群落结构,为正确评价该生态恢复区土壤环境恢复状况提供理论依据.利用湿筛倾析法、涂平板法和BIOLOG法研究了陕北黄土高原4种典型林木丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)孢子密度与土壤微生物群落结构多样性.结果表明,沙棘AMF孢子密度为刺槐的2.24倍,顺序为沙棘>狼牙刺>柠条>刺槐,不同林木土壤细菌和放线菌数量达极显著差异(p<0.01),真菌数量差异不显著(p>0.05).同一林木土壤细菌对BIOLOG-ECO板中碳源的利用优势种类和利用程度呈现明显的差异性;主成分分析表明对主成分1和主成分2贡献大的碳源为14种和8种,柠条和沙棘土壤典型变量值的变异(离散)较小,而狼牙刺和刺槐土壤典型变量值的变异较大.相关性分析表明,AMF孢子密度与细菌数量、氨基酸类、多胺类和芳香化合物类碳源呈极显著正相关(p<0.01),与真菌数量、放线菌数量和细菌总代谢活性呈显著正相关(p<0.05),但是与羧酸类、糖类和多聚物类碳源相关性不显著(p>0.05).AMF孢子密度可以作为评价陕北黄土高原林木土壤细菌生理代谢类群及其多样性的环境生物学指标.     

高浓度聚硅氯化铝(PASC)中铝的水解-聚合特性研究

以铝酸钠为碱化剂,采用缓慢滴碱法合成了高浓度(2.0mol.L-1左右)具有不同Si/Al摩尔比的聚硅氯化铝复合混凝剂(PASC).采用Al-Ferron逐时络合比色法、碱式滴定法和红外光谱分析,研究了铝的形态分布、水解-聚合历程及铝硅间的相互作用.实验结果表明,Al-Ferron络合动力学符合At=A0+A1[1-exp(-kb1t]+A2[-exp(-kb2t)];在PASC中,硅酸钠和铝的水解产物间存在着相互作用,这种作用对铝的水解-聚合历程和形态分布有不同程度的影响.用铝酸钠制备PASC时有利于Al的形态由低聚物向中、高聚物转化,且随着PASC中Si/Al比的增加生成多核羟铝配合物的能力逐渐增强.     

Effect of organic matter and pH on mercury release from soils

An investigation was conducted on the effect of organic matter(OM)and pH on mercury(Hg)release from soils.Hg release flux was measured using the dynamic flux chamber(DFC)combined with the Lumex multifunctional mercury analyzer in both laboratory experiment and field monitoring.The results showed that Hg emission from the OM-added soils was apparently low because of the high affinity of OM to Hg,resulting in the reverse order as the amount of OM addition.Meanwhile,Hg release flux from different pH value soils exhibited the same trend for both Hg~(2 )and Hg_2~(2 )treatment,increasing the Hg flux with pH value of soils increasing.The trend of Hg release in the pH dependence experiment has been well in agreement with that from the field test.In addition,Hg release seemed to be related to its species in the soil,the flux from Hg~(2 )-added soil was obviously higher than that of Hg_2~(2 )-added soil by the laboratory experiment.     

物种多样性对铅锌尾矿废弃地植被及土壤的生态效应

尾矿库是金属矿山最常见且最难恢复的废弃地.开展野外田间试验,在铅锌尾矿上建立了具有物种多样性梯度（1、4、8和16种）的植被,分析物种多样性对植物群落、重金属迁移和营养元素的影响及其生态效应.结果表明：①植物物种多样性提高了尾矿新建植物群落的盖度和生产力.1-物种的植被盖度和生物量平均值分别为33.4%和66.7 g·m^-2,16-物种的为78.4%和183.8 g·m^-2,分别增长了2.4倍和2.8倍.②植物物种多样性促进了尾矿土壤营养元素的累积.对尾矿营养元素含量随物种多样性的增加进行线性回归发现,随着植物物种多样性的提高,总有机碳（TOC）、水溶性有机碳（SOC）、总氮（TN）和总磷（TP）累积量显著性增加（TOC：r=0.30,P<0.001;SOC：r=0.20,P<0.05;TN：r=0.24,P<0.05;TP：r=0.20,P<0.05）.③植物物种多样性减少了尾矿重金属有效态含量及重金属在尾矿土壤-植物系统中的迁移和累积.重金属有效态含量随物种多样性的增加显著下降（DTPA-Cd：r=0.20,P<0.05;DTPA-Cu：r=0.19,P<0.05;DTPA-Pb：r=0.23,P<0.05和DTPA-Zn：r=0.23,P<0.05）.随着植物物种多样性的提高,植物地上部分重金属（Cd：r=-0.16,P<0.01;Cu：r=-0.23,P<0.001;Pb：r=-0.15,P<0.05和Zn：r=-0.18,P<0.001）的含量是逐渐下降的.综合分析表明,植物物种多样性对尾矿生态恢复具有促进作用.     

Polytitanium sulfate (PTS): Coagulation application and Ti species detection

Interest in the development of inorganic polymerized coagulants is growing; however, there are only limited studies on the synthesis of polytitanium coagulants, which are expected to exhibit improved coagulation efficiency with better floc properties. This study presents the synthesis of polytitanium sulfate (PTS) for potential application in water purification, followed by characterization of PTS flocs and titanium species detection. Stable PTS solutions were successfully synthesized and standard jar tests were conducted to evaluate their coagulation efficiency. Electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) speciation analysis revealed that a variety of mononuclear and polynuclear complexes were formed in PTS solution, indicating the polymeric nature of the synthesized coagulant. Floc characteristics were studied through on-line monitoring of floc size using a laser diffraction particle size analyzer. Results showed that PTS had a comparable or in some cases even higher organic matter and particulate removal efficiency than Ti(SO₄)₂. The effluent pH after PTS coagulation significantly improved toward desirable values closer to neutral pH. Properties of flocs formed by PTS were significantly improved in terms of floc size, growth rate and structure. This study showed that PTS could be an efficient and promising coagulant for water purification, with the additional benefit that its coagulated sludge can be used to recover valuable TiO₂ nanoparticles for various commercial applications.     

干旱沙区人工固沙植被演变过程中土壤有机碳氮储量及其分布特征

通过测定干旱沙区不同年代人工植被固沙区土壤剖面1 m深度容重和有机碳、全氮含量,估算了人工固沙植被演变过程中土壤有机碳和全氮储量特征及其垂直分布格局.研究表明,干旱沙区人工固沙植被演变过程中,0～100 cm深土壤有机碳和全氮储量均呈增加趋势;有机碳氮储量表现出了固沙初期的显著增加期(<16 a),随后的缓慢增加积累期(16～25 a),及后期的显著增加期(>25 a),该变化趋势主要体现在0～20 cm的表层.土壤有机碳氮储量增加程度随深度增加有降低趋势,并且表层土壤(0～20 cm)有机碳和全氮储量远大于深层土壤(20～100 cm);固沙初期土壤有机碳和全氮储量的增加体现在0～100 cm各个深度,而随后积累期主要体现在0～20 cm深度,固沙后期的增加也主要在0～20 cm深度,20 cm以下增加不明显;0～100 cm深土壤有机碳氮储量表聚性随固沙植被演变越来越明显.明确了降水<200 mm的沙区人工固沙过程中植被和土壤特征的改变对土壤有机碳氮储量及分布特征的影响,为更好地理解干旱人工植被区的碳循环特征和预测该生态系统与气候变化间的反馈关系奠定了基础.     

大伙房水库水体及沉积物砷总量及形态分布特征

以0.03 mol·L-1磷酸和0.1 mol·L-1抗坏血酸萃取沉积物样品,以2.0 mmol·L-1NaH2PO4和0.2 mmol·L-1 EDTA(pH=6.0)为流动相,采用高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)联用技术,对大伙房水库表层水体、表层沉积物孔隙水和表层沉积物中的砷元素总量及赋存形态进行检测分析,同时对大伙房库区沉积物粒度进行取样分析.检测结果表明:大伙房水库库区水体及沉积物中砷元素主要以无机砷形态存在,未检测到有机砷形态;表层水体中砷总量较低;表层沉积物孔隙水中只检测到As(Ⅲ),As(Ⅴ)未检出,且部分采样点砷总量超出国家饮用水标准(10 μg·L-1,GB5749-2006),可能会对底栖生物造成影响;表层沉积物中砷总量较高,且As(Ⅲ)含量大于As(Ⅴ),说明库区沉积环境以还原性条件为主.总体来看,大伙房水库库区水体砷总量较低,但沉积物体系中砷元素总量较高,除R4采样点外均超过国家土壤环境Ⅰ级标准(GB 15618-1995).沿外源河流输入口向库区方向砷总量降低,说明库区砷元素主要来源于外源河流输入,且以浑河为主要来源.