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901.
Electrokinetic removal of chromium and copper from contaminated soils by lactic acid enhancement in the catholyte 总被引:2,自引:0,他引:2
ZHOU Dong-mei Alshawabkeh Akram N DENG Chang-fen CANG Long SI You-bin 《环境科学学报(英文版)》2004,16(4):529-532
The electrokinetic removal of chromium and copper from contaminated soils by adding lactic acid in cathode chamber as an enhancing reagent was evaluated. Two sets of duplicate experiments with chromium contaminated kaolinite and with a silty soil sampled from a supeffund site in Califomia of USA and polluted by Cr and Cu, were carried out in a constant current mode. Changes of soil water content and soil pH before and after the electrokinetic experiments, and variations of voltage drop and electroosmosis flow during the treatments were examined. The results indicated that Cr, spiked as Cr(Ⅵ) in the kaolinite, was accumulated mainly in the anode chamber, and some of Cr and metal hydroxides precipitated in the soil sections in contact with the cathode, which significantly increased electrical energy consumption. Treatment of the soil collected from the site showed accumulation of large amounts of Cr and Cu in the anode chamber while none was detected in the cathode one. The results suggested that the two metals either complexed with the injected lactic acid at the cathode or existed as negatively charged complex, and electromigrated toward the anode under a voltage gradient. 相似文献
902.
Responses of chlorophyll fluorescence and nitrogen level of Leymus chinensis seedling to changes of soil moisture and temperature 总被引:1,自引:0,他引:1
Controlled experiment of Leymus chinensis seedlings grown in the environmental growth chambers at 3 soil moisture levels and 3 temperature levels was conducted in order to improve the understanding how leaf photosynthetic parameters will respond to climatic change. The results indicated that soil drought and high temperature decreased the photochemical efficiency of photosystem ( Fw/Fm ), the overall photochemical quantum yield of PSIl(yield), the coefficient of photochemical fluorescence quenching(qp), but increased the coefficient of non-photochemical fluorescence quenching( q, ). Severe soil drought would decrease Fv/Fm and yield by 3.12% and 37.04% under 26% condition, respectively, and 6.60% and 73.33% under 32% condition, respectively,suggesting that higher temperature may enhance the negative effects of soil drought. All the soil drought treatments resulted in the decline in leaf nitrogen content. There was no significant effect of temperature on leaf nitrogen level,but higher temperature significantly reduced the root nitrogen content and the ratio of root nitrogen to leaf nitrogen,indicating the different strategies of adaptation to soil drought and temperature. It was also implied that higher temperature would enhance the effect of soil drought on leaf photosynthetic capacity, decrease the adaptability of Leymus chinensis to drought. 相似文献
903.
904.
HUANG Zhi ZHOU Wen YU Ya-juan ZHANG Ai-qian HAN Shuo-kui WANG Lian-sheng 《环境科学学报(英文版)》2004,16(1):56-60
Enrichment of volatile organic compounds(VOC) and semi-volatility organic compounds(SVOC) in surface microlayer(SM) of three ddnking water sources were studied. The enrichment factor(EFs) were 0.67 to 13.37 and 0.16 to 136, respectively. The results showed some VOC and most SVOC could enrich in SM. Some EFs of SVOC was quite high. Suspension and temperature could affect EFs of SVOC, slim wind and water movement do not destroy enrichment of organic in SM. 相似文献
905.
Heavy metals pollution in poultry and livestock feeds and manures under intensive farming in Jiangsu Province, China 总被引:54,自引:1,他引:53
The heavy metals pollution in poultry and livestock feeds and manures under intensive farming in Jiangsu Province was investigated. 97 feed and manure samples were sampled from 31 farming plants in 10 major cities of Jiangsu. 14 metals, including Zn, Cu, Pb, Cd, Cr, Ni, Mo, Mn, Ba, Co, Sr, Ti, As and Hg, were analyzed after samples acid digestion. The results showed that the most feed samples contained high concentration of metals exceeding National Hygienical Standard for Feeds. Meanwhile, it was found that Cu, Zn, Pb, Cd and Cr concentrations in animal manures were also high, for example, Cu concentration in a manure sample reached to as much as 1726.3 mg/kg. Heavy metals loading quantities in soil per year were then calculated when metals contaminated organic fertilizers were applied, and its effects on soil environmental qualitv were further evaluated. 相似文献
906.
IntroductionThesorptionofhydrophobicorganiccontaminants(HOCs)onnaturalgeosorbentsplaysasignificantroleintheirtransport,degradationandultimatefateintheaquaticenvironment (Alexander,1995 ;Luthy ,1997;Weber,2 0 0 1) .Sincethelate 1970s,theorganicmatter(OM)ha… 相似文献
907.
为评价典型有机污染物共存情况下对长江上游三峡库区特有珍稀鱼类的环境风险,以稀有鮈鲫(Gobiocypris rarus)为对象,研究了多环芳烃和酞酸酯的代表物苯并芘(BaP)和邻苯二甲酸二(2-乙基己基)酯(DEHP)单独及复合暴露而引起的内分泌干扰效应。将成年稀有鮈鲫暴露于不同浓度的BaP(0.1、1μg·L~(-1))、DEHP(10、100μg·L~(-1))和BaP+DEHP((0.1+10)、(1+100)μg·L~(-1))中28 d后,测定了体质系数、性激素含量、下丘脑-垂体-性腺(HPG)轴和肝脏中与生殖相关基因的表达。结果表明:在雌鱼中,单独BaP或DEHP暴露对鱼体性激素含量、基因表达量无显著影响; BaP和DEHP复合暴露时,高浓度组睾酮(T)含量升高但雌二醇(E2)含量下降,fsh、vtg、 cyp17和17β-hsd基因表达量上调,cyp19a则下调,表现出协同毒性。因而雌鱼中性激素水平的改变可能与类固醇合成相关基因表达量的改变有关。而无论在单独暴露或是复合暴露情况下,对雄鱼体内性激素无显著影响。以上检测到的激素或基因表达量的改变主要发生在高剂量的复合暴露组中,而长江上游三峡库区水体中多环芳烃和酞酸酯含量低于暴露的最低浓度,因此推测,库区存在的多环芳烃和酞酸酯同时作用时不会对三峡库区上游水体中的鱼类产生生殖内分泌干扰效应。 相似文献
908.
909.
910.
基因工程菌在厌氧膜生物反应器中对偶氮染料废水的脱色 总被引:1,自引:0,他引:1
印染和染料废水色度大,COD高,可生化性差.采用基因工程菌Escherichia coli JM109(pGEX-AZR)在厌氧膜生物反应器中,对模拟偶氮染料废水进行脱色研究.结果表明,系统对酸性红B有很好的脱色能力,且启动期短,脱色效率高,脱色率稳定在95%以上,对COD的去除率能达到68%.系统运行过程中,反应器内生物量稳定在0.4 g/L.EPS与生物量变化趋势一致,先升高后降低;pH值在运行初期由6.5降至6.2,后维持在6.6左右.系统运行27 d后进行第一次膜清洗,膜通量恢复为初始值的92%,系统运行周期约为26 d. 相似文献