福建省土壤环境背景值研究

本研究采用网格和系统分层法,在全省范围内布没123个典型剖面,获得福建省61种元素土壤环境背景值。结果发现,福建省15种稀土元素土壤背景值高于全国土壤背景值。与全国若干元素土壤背景值比较,福建省亲硫元素、亲铁元素背景值较高。福建省土壤中硒、钼元素背景值分别为0.55、5.14mg/kg,相当于全国水平的2.5倍和4.3倍。文中还探讨了影响福建省土壤环境背景值的主要因素,提出福建省土壤资源合理开发利用建议。     

土壤环境质量评价指标研究及应用

随着环境影响评价工作的不断深入，尤其是在生态型开发建设项目的环境影响评价工作中，土壤环境质量评价显得更为重要，但由于缺乏评价标准，给工作带来困难，该文采用《福建省土壤环境背景值研究》课题的有关资料，探讨了福建省土壤中主要元素的环境质量评价标准及其使用原则，并进而提出了土壤环境质量评价的方法和模式。     

梅花山自然保护区土壤环境背景值研究

通过对闽西梅花山自然保护区土壤背景值的调查研究，得出了梅花山自然保护区土壤背景值，并对其主要的影响因素进行了讨论。     

土壤环境质量评价标准研究及应用

随着环境影响评价工作的不断深入,尤其是在生态型开发建设项目的环境影响评价工作中,土壤环境质量评价显得更为重要,但由于缺乏评价标准,给工作带来困难。该文采用《福建省土壤环境背景值研究》课题的有关资料,探讨了福建省土壤中主要元素的环境质量评价标准及其使用原则,并进而提出了土壤环境质量评价的方法和模式。     

福建南安市石井——东田地区土壤厚度空间分布特征及主要影响因素

在福建省南安市石井—东田地区开展了土壤垂向剖面野外地质调查,根据调查结果制作了南安市石井—东田地区土壤厚度空间分布图,探讨了该区土壤厚度空间分布特征及主要影响因素。石井—东田地区土壤厚度背景值以20cm和15cm的土壤层为主,其次为土壤厚度背景值为35cm和10cm的土壤层。福建沿海地区土壤厚度空间变异的主要影响因素为土壤成因和地面坡度。沉积环境越稳定、人为或自然干扰因素越小的区域,土壤层越厚;土壤厚度与地面坡度呈负相关,地面坡度越陡,土壤层越薄。     

福建省杉木人工林土壤亚硝酸盐还原基因丰度及其主要环境驱动因子

杉木在我国南方亚热带地区被大面积种植,导致土壤性质发生巨大变化.为揭示福建省杉木人工林土壤中亚硝酸盐还原基因(nirS和nirK)的分布特征及其主要环境驱动因子,本研究选取福建省9个主要林场的杉木人工林土壤为研究对象,使用荧光定量PCR分析了nirS和nirK基因丰度,同时测定反硝化潜势.结果表明:福建省杉木人工林土壤理化性质呈较大的变异特征,其中,pH值为4.02～5.05,为典型的酸性森林土壤.各采样点杉木人工林土壤nirS丰度均显著高于nirK,表明nirS在酸性杉木人工林土壤中占主导.随机森林和逐步回归分析均表明,土壤含水率是影响nirS基因丰度最主要的环境因子,而nirK基因丰度则主要受土壤pH值调控.相关性分析表明,nirS和nirK基因丰度分别与土壤含水率和pH值呈显著正相关.此外,土壤反硝化潜势与SOC、DOC、TN、NO₃^-、MC等环境因子呈显著相关,同时与nirK丰度呈显著正相关,但与nirS丰度无显著相关.综上,福建省杉木人工林土壤nirS和nirK基因丰度存在较大空间变异,土壤含水率和pH值分别是其主要环境驱动因子.     

影响北京地区土壤元素背景值的因素分析

用主成份分析研究了影响北京地区土壤元素背景值的主要因素。分析结果表明,影响土壤元素背景值的主要因素,在平原地区是地貌条件,在山区是成土母质。     

土壤及沉积物中重金属的环境地球化学研究

土壤由固体颗粒、土壤气体、土壤溶液和微生物及有机质组成。土壤的形成是一个缓慢的历史演变过程，一般讲，从岩石演变成2．5cm的表层土大约需要500年之久。人类需要的营养物质是直接或间接地依靠生长在土壤中的绿色植物提供的，然而在自然环境中，土壤同样受到各种污染。土壤污染物主要来自工业和城市的废水和固体废物，农药和化肥，牲畜排泄物及大气降尘等物质。1土壤重金属元素背景值土壤重金属背景值方面的研究，应当首推在七五期间，由中国环境监测总站负责完成的《中国土壤背景值》，它已由中国环境出版社于1990年出版’‘’。该书确…     

广西西江流域土壤重金属背景值再研究

为深入探究广西西江流域土壤重金属背景值状况,在大规模系统采样的基础上,从2864件土壤样品中筛选出处于自然状态下的土壤样品.通过计算不同均值并分析比较后重新提出广西西江流域土壤重金属背景值.研究结果表明,西江流域各土壤重金属背景值为(mg·kg~(-1)):As17.04、Sb 5.08、Cd 0.56、Pb 50.72、Cu 20.79、Ni 26.47、Zn 67.34、Cr 82.66.与以前研究结果相比,本研究新提出的As、Cu、Ni、Zn、Cr背景值略有差异,差异在5%以内,而Cd、Pb背景值则分别为《土壤背景值研究方法及广西土壤背景值》研究结果的4.2、2.5倍,Sb则是全国土壤背景值的4.8倍.偏高的主要原因是西江流域上游地区的南丹县、金城江、环江县、都安县、大化县、宜州市处于地球化学异常区,该区域Cd、Pb、Sb含量十分异常,使得土壤中重金属含量整体偏高.重新提出的背景值可为该流域土壤环境研究提供参考,同时为制定土壤环境质量标准提供重要依据.     

中美土壤元素背景值调查研究中数理统计方法运用及影响

土壤元素背景值是统计性的范围值,是评价土壤环境质量和制定土壤环境质量标准的重要参考依据,其因土壤母质、成因以及各种地球化学作用的影响而不同.通过分析20世纪60年代至90年代中美土壤元素背景值调查研究中数理统计方法的运用,发现当时受国内外学者对土壤元素含量及统计分析方法认识的局限,中美在土壤元素背景值研究中存在一些偏态分布被当作正态分布、对称剔除偏态分布的异常值和用平均值计算偏态分布背景值等问题,可能导致所得土壤元素背景值不能很好地代表区域背景情况.2007-2013年美国再次开展全国土壤调查和土壤元素背景值研究,对数理统计方法做出了改进和优化,主要包括:①用箱式图法分析距离中间50%数值较远的异常值;②针对对数分布形态也进行了分析;③用中位数和绝对中位偏差计算偏态分布的土壤元素背景值.在研究方法有了新的认识和发展的今天,建议中国优化土壤元素背景值数理统计研究方法,再次开展全国土壤元素背景含量调查工作,并从以下两个方面加以改进:①采用箱式图剔除异常值;②针对不同的频数分布形态计算相应的统计量作为土壤元素背景值.      

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.