土壤重金属镉、铅及其复合污染对羊蹄(Rumex japonicus Houtt)生长及其抗性生理指标的影响

为探究重金属Cd、Pb及其复合污染对植物的生长及生理的影响,选用乐安河湿地优势乡土植物羊蹄(Rumex japonicus Houtt),采用室内土培盆栽实验,分别设置不同的Cd、Pb单因素及其双因素复合污染水平,研究羊蹄的生物量、株高等生长指标及植物组织中丙二醛(MDA)、可溶性糖等抗性生理指标的变化特性。结果表明:随着Cd、Pb污染胁迫浓度的增加以及胁迫时间的延长,羊蹄的生物量及株高均受到显著(P0.05)抑制,且Cd+Pb双因素复合污染胁迫的抑制作用大于单因素Pb或Cd的污染胁迫;羊蹄植物组织中的MDA含量及可溶性糖含量随Cd、Pb污染胁迫强度的增加及胁迫时间的延长显著增加(P0.05);在盆栽土壤中单因素Cd或Pb的高浓度胁迫下,羊蹄的自我调控能力显著增强(P0.05),MDA含量下降。不同污染水平的单因素Cd、Pb及Cd+Pb双因素复合污染胁迫对羊蹄可溶性糖含量的影响均存在显著性(P0.05)差异。     

Pollution profiles and physicochemical parameters in old uncontrolled landfills

The long-term effectiveness of the geological barrier beneath municipal-waste landfills is a critical issue for soil and groundwater protection. This study examines natural clayey soils directly in contact with the waste deposited in three landfills over 12 years old in Spain. Several physicochemical and geological parameters were measured as a function of depth. Electrical conductivity (EC), water-soluble organic carbon (WSOC), Cl⁻, NH₄⁺, Na⁺ and exchangeable NH₄⁺ and Na⁺ were used as parameters to measure the penetration of landfill leachate pollution. Mineralogy, specific surface area and cationic-exchange capacities were analyzed to characterize the materials under the landfills. A principal component analysis, combined with a Varimax rotation, was applied to the data to determine patterns of association between samples and variables not evident upon initial inspection. The main factors explaining the variation in the data are related to waste composition and local geology. Although leachates have been in contact with clays for long time periods (13-24 years), WSOC and EC fronts are attenuated at depths of 0.2-1.5 m within the clay layer. Taking into account this depth of the clayey materials, these natural substrata (>45% illite-smectite-type sheet silicates) are suitable for confining leachate pollution and for complying with European legislation. This paper outlines the relevant differences in the clayey materials of the three landfills in which a diffusive flux attenuation capacity (A_c) is defined as a function (1) of the rate of decrease of the parameters per meter of material, (2) of the age and area of the landfill and (3) of the quantity and quality of the wastes.     

镉胁迫对续断菊Sonchus asper L.Hill.根系分泌物的影响

通过盆栽试验,研究了不同Cd质量分数(0、50、100、200 mg.kg-1)对续断菊Sonchus asper L.Hill.根系分泌总有机酸、游离氨基酸、可溶性糖的影响,旨在探明根系分泌物对续断菊超积累Cd的影响。结果表明:Cd胁迫下续断菊根系分泌总有机酸、游离氨基酸和可溶性糖的质量浓度显著增加,同时,总有机酸、可溶性糖和游离氨基酸又促进了植株对Cd的吸收。随着Cd处理质量分数的增加,续断菊地上部和根部镉质量分数显著增加,90 d时续断菊地上部镉质量分数与可溶性糖、游离氨基酸的质量浓度呈极显著正相关,相关系数分别为0.999(P<0.01)和0.995(P<0.01),根部镉质量分数与可溶性糖、游离氨基酸的质量浓度也呈显著正相关,相关系数分别为0.998(P<0.01)和0.987(P<0.05);Cd对续断菊根系可溶性糖的分泌、游离氨基酸的合成有刺激作用,根系分泌的可溶性糖和游离氨基酸可能在续断菊累积镉的过程中有重要作用。     

Revealing the factors affecting occurrence and distribution of polycyclic aromatic hydrocarbons in water and sediments of Lake Baikal and its tributaries

The concentrations of polycyclic aromatic hydrocarbons (PAH), total carbon (TC), total organic carbon (TOC), total nitrogen (TN) and dissolved inorganic nitrogen (DIN) in water and sediments of Lake Baikal and its tributaries were measured. It was found that according to existing water and sediment quality standards limiting permissible PAH concentrations, both surface waters and sediments in Lake Baikal watershed can be considered as unpolluted with PAHs compounds. Nevertheless, the spatial distribution of PAH concentrations in lake water indicates the existence of some point PAH sources in and around the lake. These sources were natural oil seeps and communal facilities such as residential coal-fired and oil-fired boilers. It was observed that concentrations of PAHs in both water and sediments are controlled by organic matter content and organic matter mineralisation degree, as indicated by PAH-to-carbon and nitrogen-to-carbon ratios respectively. It was found that PAH/TOC and PAH/TC ratios characterise PAH loading on water and sediments respectively, whereas DIN/TOC and TN/TC ratios characterise self-purification of water and sediments respectively. It was proved that PAH/TOC and DIN/TOC ratios can be used as tracers to evaluate the PAH contributions from tributaries to Lake Baikal.     

互花米草入侵对胶州湾湿地土壤磷赋存形态的影响

为探讨互花米草入侵对滨海湿地土壤磷循环的影响,基于时空互易原则,选择胶州湾湿地互花米草区（SA区）和光滩区（MF区）为研究靶区,分析了互花米草入侵后湿地土壤中总磷（TP）、无机磷（IP）及其组分含量的差异性以及影响因素.结果表明,互花米草入侵后湿地土壤中TP （472.70 mg ·kg^-1）和IP （239.00 mg ·kg^-1）平均含量明显高于入侵前光滩区TP （386.19 mg ·kg^-1）和IP （212.68 mg ·kg^-1）含量,增幅分别为22.40%和12.38%.研究区无机磷组分以钙磷（Ca-P）和铁磷（Fe-P）为主,分别占IP的45%~61%和31%~49%.互花米草入侵后,10~30 cm层土壤Ca-P含量显著降低（P<0.05）,7月尤为明显;Fe-P含量显著增加（P<0.05）,0~40 cm土壤层含量高于40~60 cm层（P<0.05）,并且7月在10~40 cm土壤表现出明显富集现象.通过结构方程模型发现互花米草入侵后有机质（OM）对TP和Fe-P有显著正向影响（P<0.01）,标准化路径系数分别为0.775和0.724.入侵后Fe-P对Ca-P有显著负效应（P<0.01）,标准化路径系数为-0.435.结果发现互花米草入侵总体增加了湿地土壤磷含量,同时促进了Ca-P向Fe-P转化,提高了湿地磷的生物利用性.     

镁铝双氢氧化物用于染料废水脱色的研究

以氯化铝、氯化镁、氨水等为原料,合成了镁铝双氢氧化物正电溶胶(MADH).以水溶性染料模拟废水为研究对象,检验了MADH对染料废水的脱色效果,并对其脱色机理进行了探讨. 结果表明,MADH对活性染料、酸性染料和直接染料等阴离子型染料具有明显的脱色效果.在足量MADH存在的条件下,废水脱色率可达99%以上,最佳pH为6～9,最佳反应时间为10 min.温度升高不利于吸附过程的进行,其饱和吸附容量为327～2 113 mg/g.MADH用于实际印染工业废水处理,脱色率和CODCr去除率同样较高.脱色机理为MADH对染料的化学吸附作用.MADH对阳离子型染料的去除效果较差.      

黑曲霉对水溶性染料的吸附研究

用黑曲霉对6种水溶性染料废水进行吸附脱色,当染料质量浓度为100mg／L时,6种染料废水的脱色率均达到88％以上。对培养液的光谱分析表明,染料废水的脱色是由吸附引起的。考察了氮碳源种类、碳源浓度、培养基pH和染料浓度对染料废水吸附脱色效果的影响。结果表明,（NH4）2SO4和葡萄糖是较好的氮碳源,葡萄糖质量浓度为2．5～10．0g／L时,随着其质量浓度的增加,脱色率增加;当染料质量浓度为50～200mg／L时,随着其质量浓度的增加,脱色率下降;pH对脱色率有一定的影响,但pH为4～9时,脱色率均较高。对吸附了染料的菌体进行解吸,发现甲醇是较好的解吸溶剂。     

聚合氯化铝钙的合成与应用

以氧化铝和碳酸钙为原料制备新型的无机高效水处理剂聚合氯化铝钙,研究了合成条件,确定了最佳的工艺参数。实验表明,升高温度有利于产品的合成,在10g铝酸钙粉末中盐酸加人量为70mL,酸溶时间为3h,焙烧反应中氧化铝与碳酸钙的适宜配比为3：2（质量比）。将合成的产品用于高炉煤气洗涤废水处理中,处理后的水质达到国家的排放标准和该厂的循环使用标准。     

模拟废水高温厌氧消化出水中SMP的特性研究

为考察废水高温厌氧消化出水中溶解性微生物产物(SMP)的特性,采用高温厌氧序批式反应器处理葡萄糖模拟废水,运用尺寸排除色谱(SEC)分离厌氧消化出水溶解性有机物(DOM),结合溶解性有机碳(DOC)、UV254吸光度和三维荧光光谱分析方法,对不同分离组分进行了定性和定量研究.结果表明,SMP在出水DOM(356mg/L,以DOC计)中占90.8%,其在高分子量(MW)(10k~100kDa)、中等MW(1k~10kDa)和低MW(<1kDa)内的含量分别为46.8%、45.4%和7.8%.高MW内的SMP比中等、低MW内的SMP有更高的芳香度.废水高温厌氧消化出水中SMP的荧光物质以高的酪氨酸类物质含量,低的富里酸和腐殖酸类物质含量为主要特征.低MW区域的SMP主要包括酪氨酸类物质,而富里酸和腐殖酸类物质主要集中于中等MW区域,色氨酸类和微生物副产物类物质在各MW区域内均有分布.高、中等MW区域(不含630Da相似文献   

天津市环境空气中细粒子的污染特征与来源

于2006年8─12月,在天津市中心城区采集细粒子(PM_2.5)并测定其中水溶性无机离子和元素的质量浓度,应用因子分析与多元线性回归技术解析PM_2.5的来源. 结果表明:ρ(PM_2.5)月均值为103.9～217.4 μg/m3,呈冬季最高、夏季最低的特征. 水溶性无机离子质量浓度占ρ(PM_2.5)的比例为24.90%～49.76%,其中ρ(SO₄2－),ρ(NO₃－),ρ(NH₄+)与ρ(Cl－)之和约占离子总质量浓度的90%. 在夏季,二次粒子质量浓度占ρ(PM_2.5)比例最大,这与SO₂向SO₄2-,NO₂向NO₃-的转化率升高有关. PM_2.5中Cl富集主要与燃煤等人为排放有关, 海盐源对Cl－的贡献不足20%. 天津PM_2.5中含量最高的元素为Si,约占元素总质量浓度的28.4%. 微量元素中以Zn和Pb的含量最高,二者主要来自燃煤和机动车排放. 源解析结果表明,二次污染、化石燃料燃烧、土壤尘和建筑粉尘是天津市环境空气中PM_2.5的主要来源,贡献率分别为53.4%,25.8%,12.3%和8.6%.