高效液相色谱荧光检测法测定大气中苯并[a]芘

采用反相高效液相色谱荧光检测法测定大气中苯并[a]芘含量。用甲醇超声提取采集在超细玻璃纤维滤膜上的苯并[a]芘,提取液注入反相高效液相色谱仪,通过C18反相色谱柱采用甲醇-水(体积比80比20)为流动相进行分离,采用荧光检测器进行检测,其激发波长为364nm,发射波长为427nm。分析同一溶液,测定结果的相对标准偏差(n=6)为4.6%。用标准加入法作回收试验,回收率结果在95.8%～101.7%之间     

土壤中13种有机氯农药超声波提取方法研究

应用超声波提取江西红壤和南京黄棕壤中的 13种有机氯农药 (α 、β 、γ 和δ HCH ,2 ,4′ DDT ,2 ,4′ DDE ,4 ,4′ DDT ,4 ,4′ DDE ,4 ,4′ DDD ,α endosulfan ,dieldrin ,endrin ,HCB) ,固相萃取柱进行纯化 ,气相色谱进行定量分析 .对不同提取溶剂 (正己烷、二氯甲烷、正己烷和甲醇、正己烷和丙酮、正己烷和二氯甲烷 )、提取时间 (0 .5～ 2h)、提取次数 (1～ 5次 )与提取效率的关系进行了研究 .研究表明以正己烷 甲醇 (4∶1)作为混合提取溶剂 ,超声提取一次 ,提取 2h能取得较高的提取效率 .此技术节省溶剂且提取方法简单 .     

反相高效液相色谱法测定地表水中的溴氰菊酯

采用反相高效液相色谱法测定地表水中溴氰菊酯。从萃取、浓缩、仪器条件设置等方面,对反相液相色谱法的实验条件进行优化。优化得到的条件利用二氯甲烷萃取、浓缩过程中加甲醇溶剂置换定容至1m L,在流动相为甲醇:水=7:3的条件下,用二极管整列检测器225nm波长下检测溴氰菊酯。在该条件下,该方法相关系数达到0.9999;回收率达到69.0%~100.5%;相对偏差为0.4%~2.9%;检出限低,可达0.009μg/L。利用反相液相色谱法测定地表水中溴氰菊酯操作简便,检出限低,回收率高,精密度好。     

活性污泥胞外多聚物提取方法的比较

活性污泥胞外多聚物(EPS)的定量与其提取方法密切相关。基于文献报道的提取方法,采用超声、加热、甲醛加碱等6种方法对活性污泥的EPS进行提取。测定了其中多糖、蛋白质及DNA含量,以评价提取效率及对细胞的破坏程度。结果表明,各种方法提取活性污泥EPS中的蛋白质均多于多糖,且对细胞破坏程度均较小。加热法,甲醛加碱法和超声提取法的提取效率较高,所得多糖和蛋白质含量之和分别为94.30,72.33和56.55mg/gVSS(挥发性悬浮物);通过对不同超声功率和时间的比较,表明在较低功率(25￣50W)超声,提取效率变化不大,最佳超声提取时间为4min。     

响应面法优化红肉火龙果果皮中花青素提取工艺

为验证红肉火龙果果皮中花青素的存在并探讨其提取工艺,采用超声辅助方法,以乙醇水溶液为提取剂,考察超声功率、提取温度、料液比和提取时间等因素对花青素提取量的影响,在此基础上通过响应面试验优化提取工艺。研究表明红肉火龙果果皮中有花青素存在;最佳提取条件:温度49℃、超声功率120 W、萃取时间2 h、乙醇体积分数60%,此条件下,每100 g果皮中花青素的提取量达80 mg。     

土壤中苯并(a)芘提取方法的比较研究

本文选取了索氏提取、自动索氏提取、压力流体提取、微波提取和超声提取5种常用的土壤提取方法,以苯并(a)芘为例对提取的效果进行比较研究。结果表明,这5种提取方法的精密度和准确度方面都没有显著性差异,都是适合土壤中苯并(a)芘的提取方法。在精密度方面,压力流体提取法和超声提取法略优于其他方法。在加标回收率方面,索氏提取和压力流体提取法略优于其他方法。5种提取方法提取有证标准物质,测定结果的平均值全部在置信区间内。在实际工作中,可以根据实验室具体情况选择适合的提取方法。     

膜生物反应器中EPS的提取方法

以一体式膜生物反应器(MBR)中的活性污泥为对象,以蛋白质、多糖和核酸的提取量作为污泥中附着性胞外聚合物(B-EPS)提取总量的衡量指标,研究了加热法、超声法、NaOH+甲醛法、高速离心法、蒸汽法、硫酸法等6种不同方法对B-EPS提取的最优条件;并在最优提取条件下对B-EPS提取总量进行比较分析,确定最佳B-EPS提取方法。结果表明:超声提取法、高速离心提取法、蒸汽提取法、硫酸提取法对B-EPS的提取总量较低;NaOH+甲醛法对B-EPS的提取总量虽然较高,但易导致测定出现误差,且抽滤时有结晶,影响操作;加热法对B-EPS提取效果较好,对细胞破坏程度小,且操作过程简单。因此,确定加热法为B-EPS的最佳提取方法。     

土壤中胡敏酸提取方法的优化

以国际腐殖质协会(IHSS)推荐的胡敏酸提取方法为基础,以去有机质土壤中添加胡敏酸所配制的土壤为研究对象,引入超声作为胡敏酸提取的辅助条件,采用批次试验优化了土壤中胡敏酸的提取方法。结果表明,基于胡敏酸提取回收率和精密度,在室温下获得的优化提取方法为:液土比为8:1、提取次数为3次、Na OH溶液浓度为0.05 mol/L、超声功率为120 W、超声时间为30 min;在此优化条件下,胡敏酸的回收率为94.73%±1.50%,显著大于IHSS推荐方法的回收率64.76%±0.28%,变异系数CV为1.59%、小于10%。相对于IHSS提取法,此优化提取法具有胡敏酸提取回收率高、资源节约、胡敏酸变性小、提取时间短等优点。     

环境大气尘粒中诱变物的研究：溶剂系统的比较

概要以不同的溶剂系统,包括丙酮、苯、环己烷、二氯甲烷、甲醇、丙酮与二氯甲烷的混合物及苯与环己烷及甲醇的混合物,通过振摇从大气尘粒中提取有机物质。溶剂提取物通过Ames实验进行致突变性的测定。丙酮和环己烷的提取物分别显示出最高和最低的致突变性。重复提取则更能说明问题,因为绝大多数大气尘粒中的致突变物不能被环己烷所提取。用丙酮再以二氯甲烷进行连续提取,比只用丙酮或丙酮与二氯甲烷联合提取的致突变响应更好。通过不同的溶剂量进行实验表明,每毫克大气尘粒用1毫升丙酮提取可使致突变物的重现性达到最大值。使用致突变试验来鉴别复杂的混合物对健康潜在的危险的可行性曾经通过不同的化学和生物学过程进行了测定。这些研究包括采样和分离及接下来的化学及(或)生物学活性的试验。普遍的致突变试验通常是由Ames等(1975)创立的组氨酸回复试验,这     

响应面优化原子吸收光谱法测定PM_(2.5)中镉的含量

以单因素试验最佳值作中心点,首先采用Plackett-Burman设计试验筛选出影响超声提取PM2.5中镉的4个显著因素:超声温度、超声时间、提取剂用量和硝酸浓度;其次采用Central Composite Design试验及响应面分析法建立二次回归模型,得到最佳超声提取条件为:HNO3浓度9%,超声时间47 min,超声温度68℃,提取剂用量18 m L。方法的相对标准偏差(RSD)为4.36%~6.73%,检出限为0.4μg/L。受人类活动影响受人类活动影响方法用于测定锦州市PM2.5中镉的含量,实验结果表明镉含量为0.84~4.02 ng/m3,虽然未超过浓度限值,但富集因子较大说明受人类活动影响镉在PM2.5中富集明显。     

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.     

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.     

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.     

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.     

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.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.     

Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.     

Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field ＞ tree land ＞ fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT ＞1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.     

Alterations of organ histopathology and metallolhionein mRNA expression in silver barb, Puntius gonionotus during subchronic cadmium exposure

Common silver barb,Puntius gonionotus,exposed to the nominal concentration of 0.06 mg/L Cd for 60 d,were assessed for histopathological alterations(gills,liver and kidney),metal accumulation,and metallothionein(MT)mRNA expression.Fish exhibited pathological symptoms such as hypertrophy and hyperplasia of primary and secondary gill lamellae,vacuolization in hepatocytes,and prominent tubular and glomerular damage in the kidney.In addition,kidney accumulated the highest content of cadmium,more than gills and liver.Expression of MT mRNA was increased in both liver and kidney of treated fish.Hepatic MT levels remained high after fish were removed to Cd-free water.In contrast,MT expression in kidney was peaked after 28 d of treatment and drastically dropped when fish were removed to Cd-free water.The high concentrations of Cd in hepatic tissues indicated an accumulation site or permanent damage on this tissue.