上海市区街道灰尘重金属污染研究

对上海市区街道灰尘重金属的分布特征、赋存形态及其生物有效性进行了研究,结果表明,市区街道灰尘中Pb、Cu、Ni和Zn的平均含量分别为264、182、86和673 mg kg-1,远高于上海市土壤环境背景值;重金属含量空间分布差异较大,Cu、Pb和Zn污染中心区主要位于商业区和内环线附近,Ni污染中心区主要位于外环线附近;市区街道灰尘中Pb主要以铁锰氧化物结合态存在,Cu主要以有机物结合态存在,Ni主要以残渣态和铁锰氧化物结合态存在,Zn主要以残渣态存在;其生物有效性表现为:Ni≈Pb>Zn>Cu。     

成都稻田水-土界面上锰形态的时空分布特征

以盐酸为介质,采用Tessier连续提取法及火焰原子吸收法,分析了不同时空条件下成都某地稻田水-土界面上土壤锰形态、总锰的含量及表面水、孔隙水中可溶态锰的浓度.结果表明:各形态锰含量随淹水时间、土质和灌溉条件的不同而变化.冬水田A可溶态锰的峰值于4、5、6月均出现在永-土界面下3 ～7 cm处,而水旱轮作田B的蜂值则从4月的7～8 cm上移至5、6月的4～5 cm;2块稻田均出现氧化物结合态锰随着水淹时间延长而显著减少的现象;插秧前氧化物结合态锰含量最高,插秧后残渣态锰含量最高,容易被植物吸收利用的锰形态含量很少;2块稻田因灌溉水的酸碱性不同而导致了碳酸盐结合态锰明显不同的变化趋势.2块稻田总锰含量的平均值分别为499和507μg/g,均未超过我国土壤锰的平均含量,说明该地区未受到锰的污染.     

High levels of genetic differentiation between Wolbachia-infected and non-infected populations of Folsomia candida (Collembola, Isotomidae)

The Gram-negative -Proteobacterium Wolbachia pipientis has been described as an obligate endosymbiont in many arthropod species, where it induces a variety of reproductive alterations, including parthenogenesis. Recently, this microorganism has also been detected in the parthenogenetic collembolan Folsomia candida. Here, we confirm the occurrence of the endosymbiont also in two Italian parthenogenetic populations of F. candida using ultrastructural (electron microscopy) and molecular (PCR screening on two bacterial genes) evidence. The strain isolated in the Italian populations has almost-identical gene sequences compared to that previously isolated in other populations of F. candida. In addition, we discovered a population of Folsomia cf. candida, which showed the presence of both males and females. This population is not infected by Wolbachia. A screening of two mitochondrial genes (COI and COII) showed that the bisexual population has high levels of genetic divergence in comparison with the parthenogenetic ones, even suggesting the possibility that it belongs to a different species. Furthermore, the remarkably high levels of genetic divergence between the two parthenogenetic populations suggests a possible influence of Wolbachia on inducing such differentiation, and, in the long term, speciation.     

上海不同地区土壤中硒的形态分布及其有效性研究

本文研究了上海不同地区土壤中硒的形态分布及其有效性,结果表明,土壤中硒的存在形态与土壤ｐＨ和有机质含量密切相关,土壤中硒主要以有机物－硫化物结合态及元素态存在,占总硒含量在４３～６０％,其次是残渣态,占２３～４３％,而其余三种形态仅占１２～２１％,统计分析表明,可溶态,可交换态及碳酸盐结合态硒对作物最有效,土壤有效硒的ＮａＨＣＯ３和ＫＨ２ＰＯ４浸提法都可以用作判断土壤对作物供硒能力的指标。     

当归·黄芪及当归补血汤中元素形态分析

[目的]分析当归、黄芪及当归补血汤中的元素形态。[方法]采取中药常用煎煮方法对当归、黄芪及当归补血汤中Ca、Cu、Fe、Mg、Mn、Sr和Zn7种元素进行提取;用0.45μm滤膜分离煎液中的可溶态和不溶态;利用XAD-2大孔树脂将可溶态中元素分为有机态和无机态;采用ICP-AES法对各种形态中的7种元素进行测定。[结果]结果表明:当归、黄芪、当归补血汤药材及煎液中Ca、Fe、Mg、Zn的含量较高,7种金属元素的煎出率在8.77%~76.49%,煎液中各元素主要以可溶态形式存在,而在可溶态中又主要以无机态形式存在,当归、黄芪配伍共煎后对各元素形态变化并无规律性整体增加或减少。[结论]为进一步分析中药中金属元素的存在形态,深入探讨金属元素在中药药材、药效方面的作用机制提供了一定的理论基础。     

巢湖东部水源区及入湖河流无机氮形态特征及影响研究(英文)

[目的]对我国巢湖东部水源区及入湖河流无机氮的形态特征及其影响进行研究。[方法]研究巢湖东部水源区及入湖河流溶解性无机氮(DIN)的形态组成和分布特征,并探讨它们对水质的影响。[结果]NH3-N、NO2--N平均浓度在汛期较高,非汛期较低,NO3--N正好相反;双桥河口NH3-N浓度远高于其他各点,污染最为严重。柘皋河口、小柘皋河口DIN主要为生活污水及工业废水污染所致;双桥河口地表径流、船舶污染等对DIN含量贡献较大。[结论]该研究为巢湖富营养化控制和治理提供了基础数据和理论依据。     

Fecal polymerase chain reaction with 16S ribosomal RNA primers can detect the presence of gastrointestinal Helicobacter in dogs

Questions about pathogenesis and therapy for Helicobacter infections in dogs could be answered with a simple, noninvasive, sensitive, and specific diagnostic test. We hypothesized that a fecal polymerase chain reaction (PCR) assay would detect Helicobacter and could be useful for assessing therapeutic responses. Paired gastric biopsies and fecal samples were obtained from 39 random source dogs (group 1). Gastric biopsies from each of these dogs had histologic evidence of gastric spiral bacteria, and paired gastric tissue and fecal samples produced a 375-base pair (bp) product when amplified by PCR with Helicobacter-specific primers. Specificity of the PCR product was confirmed by detection of expected 60-, 119-, and 196-bp products following Hinfl digestion. Direct sequencing of amplicons from paired PCR products from gastric biopsy and fecal samples from 8 group I dogs showed that gastric products had the highest homologies with known gastric Helicobacter species, whereas fecal products had the highest homologies with intestinal species. Healthy mixed-breed dogs (group II; n = 8) with histologically confirmed spiral bacteria infection were treated with a 21-day course of metronidazole, amoxicillin, and famotidine. Fecal samples were collected from group II dogs twice before and within 3 days of completion of treatment. The PCR results correctly identified 15/16 pretreatment samples as positive: 1 pretreatment sample was negative. PCR results identified 8/8 posttreatment samples as Helicobacter negative. Fecal PCR is a useful test for detecting Helicobacter infection in dogs. This assay may be useful as a screening test for infection and could be used to address questions relevant to pathogenesis and therapy.     

海藻中铝形态分析技术

建立了高效液相色谱-电感耦合等离子体质谱联用技术（HPLC-ICP-MS）分析海藻及其制品中三价铝的方法,用提取液0.040 mol/L氢氧化锂＋0.006 mol/L吡啶-2,6-二羧酸＋-0.090 mol/L冰醋酸在70℃恒温水浴摇床中浸提2h,阳离子交换色谱柱分离,ICP-MS检测.样品加标量在5.0 mg/kg和50.0 mg/kg时的平均回收率在90.8％以上,相对标准偏差均＜4％（n=5）.本研究证明,该方法测定海藻及其制品中的三价铝较为准确、可靠,可为制定农业行业标准提供技术支撑.     

玉米对镉的累积特性及镉的存在形态研究

[目的]研究北方地区常见农作物玉米对土壤中镉的吸收分布规律及镉的存在形态。[方法]利用镉污染地土壤,采用盆栽试验法种植玉米,研究玉米不同部位对镉的吸收。采用单独溶剂提取法,分别对玉米根、茎叶和种子中的镉进行提取。[结果]玉米中各部位含镉量依次为果实〈茎叶〈根。各部位对镉的富集系数均小于1。对玉米不同部位中镉的形态分析表明,有机态镉含量最低,其次是水溶态镉,酸溶态镉最多。在所研究的形态中,果实中各形态镉所占的比例最高,茎叶居中,其次是根。[结论]玉米各部位对镉的累积具有较大差异。不同溶剂对玉米各部位镉的提取能力不同。     

阳宗海水体中砷的形态分布特征及来源研究

采集云南阳宗海湖水和表层沉积物样品,运用地球化学的原理与方法研究了高原湖水环境中砷（As）和其他重金属的含量、存在形态及空间分布,采用原子荧光分光光度法直接分析了样品中As的形态,并在此基础上对其健康危害风险进行了评估。结果表明,该湖泊水体中As的污染已达到较高的水平,对水域周围环境造成较高的环境健康危害风险。湖水中As（Ⅲ）的含量为51.4～350.7μg/L,平均含量为84.0μg/L;As（V）的含量为66.1～988.7μg/L,平均含量为156.1μg/L;总As含量平均值为167.0μg/L。其中该湖泊泉水中As（Ⅲ）的含量为17500.0μg/L,As（V）的含量为12200.0μg/L,具有极高的健康危害。湖水中其他重金属如Fe、Mn、Cu、Zn、Co、Pb的含量均好于国家Ⅱ类水标准,Ni、Cd超国家IV类水标准。结果还表明,该高原湖泊As的存在形态及分布特征与某工厂的排污活动相关。