单甲脒残留量的气相色谱分析

以气相色谱法分析水果和土壤中单甲脒的总残留量。单甲脒及其代谢物先水解成2.4—二甲苯胺,经石油醚萃取,酸碱液液分配净化,七氟丁酸酐衍生化后,用带有电子捕获检测器的气相色谱仪检测。柑桔和土壤中单甲脒的最低检测浓度分别为1ppb和5ppb。单甲脒的添加浓度在0.25～2.0ppm范围内,在柑桔和土壤中的平均回收率分别为82.4％±5.4％和82.8％±2.3％。     

农药单甲脒盐酸盐在棉田生态系统中的残留及持久性研究

单甲脒盐酸盐属低残留非持久性农药。在棉叶中的半衰期为４．４－８．ｌｄ,在土壤中为１１．４—１２．３ｄ。分别以２５％单甲脒盐酸盐水剂的１０、５０、１００、５００、８００、１０００和１５００倍稀释液喷施７—８次,每次间隔约１５ｄ,在棉籽中检测出单甲脒最高残留为０．１７×１０－６。科学合理地施用单甲脒农药,不会对人体健康造成危害。     

固定化甲烷八叠球菌(Methanosarcina)研究——厌氧颗粒污泥的形成

用实验室规模的UASB反应器处理豆制品废水培养厌氧颗粒污泥。通过对颗粒污泥形成过程中的产气率、进出水COD、水滞留期（HRT）、进出水挥发酸（乙酸、丙酸和丁酸）浓度、所产气体的甲烷含量等的变化分析和对颗粒污泥中优势产甲烷菌的扫描（SEM）和透射（TEM）电镜观察,阐明颗粒污泥的形成过程及特性。实验结果表明,消化器运转50d左右形成了颗粒污泥,厌氧颗粒污泥形成期间的平均产气率为5.3L/L·d,最高产气率达到了8.1L/L·d,进水和出水COD分别为3000～5500mg/L和800～3000mg/L,平均HRT为10.4h,平均出水乙酸、丙酸和丁酸浓度分别为264.1、519.8和104.6mg/L,所产气体的平均甲烷含量为60.6％,颗粒污泥为黑色,直径0.5～3.0mm不等,沉降速率为119.6m/h,其中的优势产甲烷菌为鬃毛甲烷菌（Methanosaeta）,而甲烷八叠球菌（Methanosarcina）存在甚少。     

两种硝基氯苯对鲤鱼的急性毒性

采用鲤鱼(Brocarded Carp)为试验生物对对氯硝基苯(P-NCB)和2,4-二硝基氯苯(DNCB)2种化合物进行了静态方式的急性毒性试验。结果表明,96h后,对氯硝基苯试液中鲤鱼24h 100%死亡浓度(24h LC100)和96h无死亡浓度(96h LC0)分别为:40mg/L和5mg/L;在25～27℃下,96h的LC50为22.13 mg/L。2,4-二硝基氯苯试液中鲤鱼24h 100%死亡浓度(24h LC100)和96h无死亡浓度(96hLC0)分别为:1.0mg/L和0.5mg/L;在20～22℃下,96h的LC50为0.692 mg/L。该研究表明,对氯硝基苯和2,4-二硝基氯苯对鱼类分别属于高毒物质和剧毒物质。     

斜生栅藻与单甲脒的相互作用

为研究斜生栅藻与单甲脒的相互作用,采用评价化学品对藻类毒性的标准实验方法出了单甲凶制斜生栅藻生长的９６ｈ－ＥＣ５０为６．５ｍｇ／Ｌ。实验结果表明,在单甲脒浓度分别为２,４和８ｍｇ／Ｌ下,斜生栅藻都不具备降解单甲 能力。     

鱼类对4种农药的回避反应研究

测定鱼类回避反应的阈限浓度是评价水质污染和研究农药毒性的一个重要指标。采用TL－86型鱼类回避槽,研究了鲤鱼对甲基异柳磷等4种农药的回避反应。结果表明,鲤鱼对克草胺、嘧啶氧磷和甲基异柳磷３种农药的平均回避浓度分别为20ppb、86ppb和100ppb,比其相应的半致死浓度LC50值约低10至20倍,说明鲤鱼对这3种农药有明显的回避性能。单甲脒对动物具有麻痹作用,鲤鱼接触药剂后即发生迟呆现象,毫无回避能力。     

温度、氨对鲢、鳙、草、鲤鱼的影响

为制定热排放标准的需要,用动态实验和静态实验方法研究了热冲击与氨对鲢、鳙、草、鲤鱼的急性和亚急性效应。结果表明：选择温度与起始致死温度（TL₅₀）值随着驯化温度的升高而增大,鳙鱼对热冲击的反应较敏感。氨对鲢、鳙、鲤鱼的急性毒性（96h）LC₅₀值分别为0.38、0.30、0.66mgNH₃/L（非离解氨）。水温升高5℃,鲤鱼的（96h）LC₅₀。值从0.66mgNH₃/L下降到0.44mgNH₃/L,热冲击明显提高了氨对鲤鱼的毒性。氨对鲤鱼的亚急性毒性结果表明,鳃、肝组织出现了病理改变。以上室内实验结果可作为评价监测热污染水质的科学依据。     

国家“七五”攻关项目——“单甲脒残留试验研究”通过鉴定

单甲脒是一种高效杀螨剂。其大规模生产、推广和出口,要求进行作物残留试验。由浙江工学院、浙江省农业厅、商业部杭州茶叶加工研究所、北京市植保站、化工部科技研究总院等单位合作的“七五”攻关课题——“单甲脒残留试验研究”,于今年9月中旬在杭城通过鉴定和验收。该项研究首先提出了单甲眯残留特性、安全使用标准及最大残留限量(MRL)推荐值:攻克了残留分析技术难关,建立了可行、适用的单甲脒分析方法;其     

单甲脒农药对的毒性研究

在２０℃条件下应用换液的方法研究单甲脒农药对大型（Ｄａｐｈｎｉａｍａｇｎａ）、方形网纹（Ｃｅｒｉｏｄａｐｈｎｉａｑｕａｄｒａｎｇｕｌａ）、老年低额（Ｓｉｍｏｃｅｐｈａｌｕｓｖｅｔｕｌｕｓ）的急性毒性和慢性毒性．结果表明，单甲脒对类的毒性中等，４８ｈＥＣ５０值在５５２—１５１４ｍｇ／Ｌ之间，老年低额比较敏感，大型耐性较强．２１ｄ繁殖实验结果获得单甲脒对老年低额的最大无影响浓度（ＮＯＥＣ）为００３２ｍｇ／Ｌ，最低有影响浓度（ＬＯＥＣ）为００６３ｍｇ／Ｌ，其最大允许浓度（ＭＡＴＣ）估计为００５ｍｇ／Ｌ，应用系数为００１．溶液ｐＨ值对单甲脒毒性有明显影响，其毒性随ｐＨ值的增加而下降     

单甲脒盐酸盐的酸性、中性和碱性水解的动力学过程

单甲脒盐酸盐的酸性、中性和碱性水解的动力学过程颜文红，雷志芳，叶常明（中国科学院生态环境研究中心，北京１０００８５）关键词：单甲脒盐酸盐；水解；酸碱度。１引言单甲脒碱，化学名称为Ｎ—（２，４－二甲苯基）—Ｎ＇－甲基甲脒，简称ＤＭＡ，是一种新型高效的有...     

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.     

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.     

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.     

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.     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

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

ＲｅｍｏｖａｌｏｆｈｅａｖｙｍｅｔａｌｓｆｒｏｍｓｅｗａｇｅｓｌｕｄｇｅｂｙｌｏｗｃｏｓｔｉｎｇｃｈｅｍｉｃａｌｍｅｔｈｏｄａｎｄｒｅｃｙｃｌｉｎｇｉｎａｇｒｉｃｕｌｔｕｒｅＷｕＱｉｔａｎｇ，ＮｙｉｒａｎｄｅｇｅＰａｓｃａｓｉｅ，ＭｏＣｅｈｕｉＦ...     

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.     

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.