北江河水中抗生素抗性基因污染初步研究（Preliminary Studies on the Pollution Levels of Antibiotic Resistance Genes in the Water of Beijiang River, South China）

环境中细菌的耐药性,尤其是对抗生素的耐药性已成为影响生态环境的重要因素.论文采用抗生素抗性平板法调查了北江河水中四环素、红霉素及磺胺类这3类抗生素耐药性细菌的存在,采用定性PCR及荧光定量PCR方法分别研究了该水域sul1和sul2这2种磺胺类抗生素抗性基因(ARGs)的存在和含量水平.结果表明,所采集北江水域的9个样品中有5个对四环素有耐药性,7个对红霉素有耐药性,8个对磺胺二甲嘧啶有耐药性;定性PCR实验并经基因测序结果证实,5个样品含有sul1,4个样品含有sul2.进一步的PCR定量分析结果显示,7个样品中均检出sul1和sul2磺胺抗性基因,它们与内对照基因16S-rRNA表达量比值分别在10-2.56~10-0.52及10-3.25~10-1.24范围内,该结果显著高于美国科罗拉多州北部河流的研究结果.此外,数据分析也发现,sul1和sul2磺胺抗性基因的含量水平与该区域水中磺胺含量分布具有一定的相关性,表明外源性抗生素对河流的污染是诱导抗性基因的重要因素.     

测定废弃线路板中重金属的酸消解方法比较

重金属含量一般采用原子吸收光谱仪(AAS)、电感耦合等离子体发射光谱仪(ICP-MS,ICP-AES)等方法测定.测定前需要对固体样品进行预处理.目前,常用的预处理方法有直接加热酸消解法、微波消解法和高压釜消解法等.而直接加热酸消解法是目前相对最常用的方法.     

崇明岛公路两侧蔬菜地土壤和蔬菜重金属污染研究

为了研究崇明岛公路两侧土壤和蔬菜重金属污染状况,采集陈海、北沿公路两侧蔬菜地土壤、蔬菜和路面灰尘样品,测定重金属Pb、Cd、Cu、Zn含量.结果表明,以上海市土壤环境背景值上限值为评价标准,所有土壤样品Pb、Cd、Cu和Zn的超标率分别为10.1%、25.4%、6.5%和8.7%;以HJ 332-2006 食用农产品产地环境质量评价标准中蔬菜地土壤环境质量评价指标限值(pH值6.5～7.5)为标准,Cd超标率在21.0%,仅有不到3%样品Pb含量超标,而没有样品Cu、Zn含量超标.以国家食品卫生标准中规定的重金属限量为标准,路侧蔬菜样品Pb含量超标率为43.2%,Cd为18.6%,Zn和Cu则小于5%.由此可见,崇明岛主要公路两侧土壤污染以Cd为主,而蔬菜污染则以Pb为主.在长期运营的前提下,低交通量公路两侧50 m范围内耕作层土壤和两侧作物会发生一定程度的重金属污染,路面灰尘是路侧土壤和蔬菜的潜在污染源.     

电感耦合等离子体质谱法分析锰结核中的多种元素含量

本文使用岛津ICPMS-2030电感耦合等离子体质谱仪,采用微波消解法对锰结核样品进行前处理,测定了锰结核样品中32种元素含量.实验结果表明,各元素在1.0—100μg·L^-1范围内线性关系良好,相关系数均大于0.9998,检出限低,各元素检出限都在0.00004—0.73μg·g^-1之间.该方法操作简便、快速,测试结果准确,使用锰结核标准物质GBW07296进行验证,测定值与标准值基本吻合,该方法可适用于锰结核样品中多元素含量的测定.     

不同处理方法对降水中污染元素来源评估的不确定性讨论——以西藏拉萨和纳木错为例

在降水元素测试中对降水样品的前处理通常有两种方法:样品直接酸化和过滤后酸化.不同的处理方法会得到不同的结果,并最终影响到对元素来源的解释.为明确这两种处理方法对降水中重金属元素来源评估的影响,本文选取青藏高原的典型城市拉萨市和典型的背景区纳木错,对采集的24个降水样品用上述两种方法进行处理,并对两组样品中的15种金属元素的含量和富集因子进行了对比.结果表明,两个研究点过滤后样品元素含量都显著低于未过滤样品的元素含量,其中拉萨未过滤降水样品中的常量元素Al和Fe的含量分别比过滤后样品中的含量高约50和20倍,表明降水中的Al和Fe主要以颗粒态存在.相应地,典型污染元素如Cu、Zn和Cd等在两种样品中的含量变化相对较小,表明这些元素在降水中主要以溶解态存在.同样地,纳木错降水样品中元素也存在类似的变化特征.由于上述原因,拉萨和纳木错过滤后的降水样品中大部分元素(如Ni、Zn和Cd)的富集因子值高于未过滤样品中的值.因此,对降水样品过滤会导致一些典型污染元素的富集因子值增高,进而高估人类活动对这些元素的贡献.所以,用未过滤的降水样品进行元素富集因子研究得到的结果会更接近实际情形.     

应用ICP-MS技术分析土壤及污泥中的关键元素的方法研究(二)

ＰＴＦＥ密封罐消解方法虽然可以对多数土壤的全消解标准物获得满意的结果 ,但该方法使用了高危险高腐蚀性的ＨＦ ,长期分析必须给ＩＣＰ ＭＳ仪器安装昂贵的抗ＨＦ的Ｐｔ锥系统 .ＰＴＦＥ密封罐消解必须将样品加热过夜 ,样品处理周期较长 .如果改用微波炉加热方法将进一步提高     

不同产地野生鱼腥草根、茎、叶中常量和微量元素含量的比较研究

为开发和利用鱼腥草提供一定的科学依据,研究采用微波消解技术处理样品,利用电感耦合等离子发射光谱法测定了我国广西,湖南和云南三个不同产区鱼腥草地下茎,叶片和花中S,P,K,Ca,Mg,Fe,Zn,Cu,Mn和Se等十种常量和微量元素的含量.研究结果表明:不同产地鱼腥草元素的含量呈现地域差异,鱼腥草不同部位元素的含量存在差异.同一部位不同元素的含量也不尽相同.鱼腥草中含有丰富的S,P,K,Ca,Mg.分析结果的平均回收率在95.3%~102.8%之间.该方法简单,快速,可靠,灵敏度高,且多元素可同时测定,能满足实际样品分析要求.测定结果为进一步探讨鱼腥草中元素的含量与其功能的相关性提供了参考.表3,参14.     

竹子生物质废弃物前处理技术比较研究

为开发高效、低成本的预处理技术,促进竹子生物质及其废弃物资源的能源化利用,采用3种不同纤维素预处理方法分别对竹子生物质废弃物——笋壳和竹叶(茎)进行比较研究,同时与玉米秸秆相比较.结果表明,在稀H2SO4–酶解工艺、浓H3PO4–酶解工艺和NaOH–酶解工艺条件下,几种样品水解液中分别存在3、4和5种糖类组分.在稀H2SO4–酶解工艺中,木糖为主要成分,其次为葡萄糖;在浓H3PO4–酶解工艺中,葡萄糖为主要成分,其次为木糖;而在NaOH–酶解工艺,葡萄糖和木糖含量基本相当.同时对样品处理前后的表面结构变化分析表明,不同处理工艺均改变了竹叶(茎)、笋壳和秸秆等样品的表面结构,其结构更为松散,从而有利于纤维素的酶解.     

我国沿海地区贝类样品中十溴联苯醚污染水平分析

BDE-209是溴代阻燃剂十溴联苯醚的主要成分,本研究应用GC-NCI-MS(气相色谱-负化学源-质谱)方法同位素稀释技术,测定了从沿海五省采集的48份贝类样品中BDE-209含量.所有样品中均检出BDE-209,含量范围为16.24—445.35 ng.g-1湿重,平均含量(61.29 ng.g-1湿重)显著高于国内外相关报道.其中,采自辽宁省的海蛎子样品BDE-209含量最高.结果提示,我国有关海域存在较为严重的BDE-209污染,应引起有关部门的关注.     

土壤重金属测定两种前处理方法的比较

样品的前处理方法对于土壤中重金属含量的准确测定是一个重要的环节.国外许多文献是基于对土壤样品的王水消解方法,如ISO方法11466和欧洲DIN 38414-S7王水法,该方法广泛地应用于土壤、沉积物和灰尘等复杂基体的研究.而我们多采用混酸完全消解的方法,如国家标准方法GB/T17140和GB/T17139等;台湾环境监测所公布的土壤消解方法(NIEA S321.63B)近似国外的王水消解法,与美国环保局USEPA SW846-3050酸溶方法也有些类似. 本文用四酸完全消解法和王水提取法进行研究,并对上述方法在三种不同土壤重金属含量条件下对测定结果的影响做一比较,为类似研究提供参考.     

土壤重金属X射线荧光光谱非标样测试方法研究

采用粉末压片制样,用X射线荧光光谱非标样测试方法测定土壤中Ti、V、Cr、Mn、Fe、Ni、Cu、Zn、Ga、As、Cd、Sn、Sb、Pb、Hg等15种重金属元素。研究了样品制备方法和元素测量条件等影响测试准确度的因素。结果表明此方法不需对固体样品进行消化处理,无需制备标准样片,快速、简便、效率高,是一种非破坏性的分析方法,方法的检出限、准确度和精密度基本能够满足土壤中有毒有害重金属的快速筛查要求。     

Improved sample preparation and GC–MS analysis of priority organic pollutants

Mass spectrometry is a major tool for analysing organic pollutants. However, scientists often complain about laborious sample preparation. The development of new commercial high-resolution mass spectrometers gives a chance to improve simultaneously speed, reliability, and sensitivity of the analysis. Here, we used the time-of-flight high-resolution mass spectrometer Pegasus GC-HRT to identify and quantify 55 priority organic pollutants in water samples. This mass spectrometer has a high resolution of 50,000, a high mass accuracy of about 1 ppm and a very high acquisition rate of up to 200 full mass range spectra per second. 1 mL water samples were extracted with 1 mL dichloromethane. Results show that the sample preparation and analysis are achieved 30 times faster, requiring 1,000 times less water and 350 times less solvent than the classic 8270 method of the United States Environmental Protection Agency. The detection limit is 1 μg/L. The quantification limit is 10 μg/L. Our procedure, named accelerated water sample preparation, is simpler, faster, cheaper, safer and more reliable than 8270 Method.     

Effects of nanopesticide chlorfenapyr on mice

The effects of chlorfenapyr nano preparation on mice were examined. The animals were administered with different doses of 4.84, 9.68, or 19.36?mg?kg^?1 of chlorfenapyr common preparation or nano preparation intraperitoneally (IP). Micronucleus (MN) test and comet assay (CA) experiments revealed that at the same dose, similar DNA damage in the peripheral blood lymphocytes of the mouse and chromosome damage in bone marrow cells of the mouse occurred with chlorfenapyr nano preparation; however, the severity of these effects was less than that found in common preparation. It is noteworthy that there were no differences in apoptotic ratio and live cell percentage in the liver cells of the mouse between these two pesticide formulations using flow cytometry. Data indicate that chlorfenapyr nanoformulation is less toxic to mouse cells than the common formulation.     

A better method for standardizing vitellogenin content of fish tissues

Vitellogenin (vtg) concentrations were measured in plasma and liver samples from 12 hybrid Tilapia oreochromis niloticus x O. aureus to compare concentrations in these tissues. The results were calculated under two different normalizations: volume per gram of sample used (similar to normalization usually published in the literature and typically used for ELISA) and volume per total protein (similar to normalization used in polyacrylamide gel electrophoresis; PAGE). It was observed that the normalization procedure used in PAGE (per gram total protein) minimized the method detection limit by about 1000 and 2500 times in plasma and liver respectively, compared to the normalization usually reported in the literature. It was also observed that normalizing per gram total protein makes it possible to eliminate a potential problem of accidental dilution of plasma samples during sample collection. Moreover, the normalization on a per gram of total protein makes it possible even to compare results from the two different methods namely PAGE and ELISA. It also allows comparison between different tissues. Using the normalization procedures as used in PAGE (per gram total protein) for liver and the normalization method as reported in literature for ELISA (per volume of sample used), it was observed that liver samples had higher vtg levels (mean: 62 microg vtg/g) compared to the corresponding plasma samples (mean: 0.24 microg vtg/ml). However, when both results were normalized per gram total protein all but one liver sample were lower (62 microg vtg/g) than the corresponding plasma concentrations (mean = 246 microg vtg/g).     

Study of trace elements in urine of some Nigerian medical patients

In this study, trace element concentrations were determined in urine samples of patients with kidney and liver conditions from the Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife Nigeria. Urine samples from 80 patients whose ages ranged from 15 to 79 were used for the trace metals analysis. Variation of the trace metals including lead (Pb), cadmium (Cd), mercury (Hg), zinc (Zn), copper (Cu), and manganese (Mn) in urine samples were correlated with respect to gender, age, professions, personal habits and patients’ conditions. The levels of Pb in the urine samples of both male and female patients were found to be generally higher than those of Cd, Hg, Zn, Cu, and Mn. Highest levels of Pb and Cd were found in patients who smoked and drank and those with various kidney and liver conditions. Most of the trace metals except Mn occurred at levels that are deleterious to human health as they are above the standard threshold values expected in normal human urine, and raised cause for concern.     

Analysis of volatile fatty acids by ion-exclusion chromatography,with special reference to marine pore water

A method for measuring volatile fatty acids using ion-exclusion chromatography is presented. The system was found to be applicable to samples with high salt concentrations (e.g. seawater and marine pore water) when coupled with a vacuum distillation procedure. The method is straightforward, with no sample preconcentration and no introduction of external contamination. Calibration was found to be linear, with good reproducibility (coefficient of variation normally less than 5%) and the system was sufficiently sensitive to operate at the sub-ppm level (minimum detection limit for acetate and propionate was approximately 0.02 and 0.05 ppm, respectively). This technique was used to investigate the distribution of volatile fatty acids with sediment depth at Station E70 in Loch Eil, Scotland (sample was collected in March, 1983) and the results were in good agreement with recent publications. Although the system, at present, is limited in marine pore water to acetate and propionate, it has certain advantages over alternative systems and these are described.     

Influence of hydrostatic pressure on l-glutamate dehydrogenase from the Antarctic fish Chaenocephalus aceratus

The influence of hydrostatic pressure on the stability and activity of glutamate dehydrogenase (GDH) from the liver of the Antarctic fish Chaenocephalus aceratus (Notothenioidei: Channichthyidae) has been investigated using the homologous bovine enzyme for comparison. At gradually increasing pressure, the fish GDH retains all activity up to 140 MPa, whereas in the same pressure range the bovine enzyme is slightly inactivated. The kinetics of pressure-induced inactivation of Antarctic GDH displays an exponentially decreasing residual activity as a function of the incubation time, whereas the bovine enzyme shows a complex pattern of behaviour in the first 20 min of incubation, attributable to the transient formation of aggregates. The coenzyme NAD increases the stability of both enzymes. The activation volume calculated for the reaction catalysed under pressure by fish GDH is higher than that of the bovine enzyme. These results indicate that the molecular properties of fish and bovine GDH are affected differently by hydrostatic pressure. A common mode of inactivation under extreme conditions of pressure and temperature of the cold-adapted Antarctic fish and mesophilic bovine GDH is deduced and discussed. Received: 20 October 1998 / Accepted: 7 May 1999     

Voltammetric analysis of metallothioneins and copper (II) in fish for water biomonitoring studies

An major research area in environmental chemistry is the development of methods for the analysis of biomarkers. Metallothioneins are used as biomarkers in studies of heavy metals exposure in water, because metallothioneins are synthesized and accumulated when organisms are exposed to toxic concentrations of pollutants. In this work, simple and sensitive voltammetric methods were developed for metallothionein and copper (II) determinations in fish liver Lepomis gibbosus. Both analytical methodologies were optimized and applied to samples extracted from individuals previously submitted to sub-lethal toxicological trials with copper sulphate (CuSO₄) and cadmium chloride (CdCl₂). The obtained results showed that both methods are very precise, sensitive, and involve simple sample preparation processes. Moreover, metallothioneins showed better correlation with the toxic exposure than Cu²⁺. To the best of our knowledge, this is the first time that hepatic metallothioneins and Cu²⁺ contents are voltammetrically determined in order to be compared in their function as heavy metal biological indicators.     

动态浸滤及几种静态预测法对云浮硫铁矿酸化特征及产酸潜力的比较

用几种静态预测方法研究了来自云浮硫铁矿矿石的产酸潜力,并结合动态浸滤试验方法对比了新旧矿石的氧化过程及产酸的动力学特征.静态预测结果表明:该矿矿石的净中和酸潜力NNP<-20、中和酸能力与产酸潜力比NP/AP<1:1、静产酸量NAG>10、NAG-pH<4,是强产酸矿.连续25周的动态浸滤试验研究表明:受碳酸盐控制,新矿浸滤液的pH值在7.46—6.45呈缓慢下降的趋势,25周内减小了近1个pH单位;旧矿已经产酸,浸滤液初期pH<4,10周内迅速下降到pH<3,体系氧化性及硫化物的氧化速率远远高于新矿,金属的释放大大增加.     

Soxhlet extraction of organic compounds associated with soil water repellency

The study of compounds associated with soil water repellency usually involves removing organic material from a sample by some extraction procedure. An evaluation of the kinetics and efficiency of Soxhlet extraction using an isopropanol-aqueous ammonia mixture is given here. Increasing extraction time caused an increase in the mass of material extracted and a decrease in soil water repellency. The same compound types were detected by gas chromatography-mass spectrometry in all extracts, but their proportions varied with extraction time. In particular, the removal of alkanes from the soil sample was less rapid than that of more polar compounds.