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1.
施加不同电压对铬污染黄棕壤电动过程的影响   总被引:10,自引:0,他引:10  
仓龙  周东美 《土壤学报》2005,42(6):999-1005
研究了在控制阴极液酸度条件下,施加不同电压对铬污染黄棕壤中铬的电动过程的影响,结果表明增加应用电压显著提高了处理电流和电渗流量,所有电动处理后土柱中土壤pH均在3左右,低pH环境引起土柱中铬的氧化还原和沉淀反应并导致土柱中电压降的不均匀分布。施加20 V电压处理获得了较好的铬去除率和较低的能耗,576 h后土壤中总铬和六价铬的去除率分别达到41.1%和77.7%。控制阳极池溶液酸度将是一个能够显著提高土壤铬去除的有效方法。  相似文献   

2.
制革场地土壤和地下水中铬污染来源及污染特征研究进展   总被引:3,自引:0,他引:3  
徐腾  南丰  蒋晓锋  唐余玲  张文华  石碧 《土壤学报》2020,57(6):1341-1352
近年来,制革场地土壤和地下水中的铬污染引起了国内外广泛关注。通过分析制革工艺流程、废水和固废的性质及其处置的历史与现状,提出制革场地的铬污染源自含铬浴液和废水的滴漏以及固废和污泥的不当堆置与填埋。制革场地土壤铬污染以三价铬为主,六价铬含量相对较低,但部分仍远超国家标准限值。污染主要集中于生产车间、污泥存放点和废水排放点,场地表层土壤全铬远高于深层土,且污染时间短的场地土壤中有效态铬(交换态铬和水溶态铬)含量较高;而地下水中的总铬和六价铬,受土壤铬分布、污染时间、水文地质等多种因素影响。针对制革场地伴有酸碱和有机物污染的特点,进一步论述了有机物和土壤pH对铬在土壤中环境效应(迁移、形态转化和氧化)的影响,指出应重点关注有效态铬和六价铬的含量和形成机制。最后讨论了制革场地铬的环境风险防控主要面临的挑战和对策。  相似文献   

3.
化工厂遗留地铬污染土壤化学淋洗修复研究   总被引:3,自引:0,他引:3  
李世业  成杰民 《土壤学报》2015,52(4):869-878
选取了济南市某铬渣堆放场地表土壤为实验目标,采用振荡淋洗法研究了水、EDTA、柠檬酸、盐酸、Ca Cl2、Na OH和磷酸等淋洗剂对铬污染场地铬污染物的淋洗效果,并从中筛选出最佳淋洗剂,探讨了淋洗剂浓度、土液质量比、振荡淋洗时间、淋洗液p H等对淋洗条件的影响。结果显示,选取的土壤样品均超过国家土壤标准,钛白生产车间土样污染程度最轻,北部厂区污染最重,最高铬污染物含量达到7 149 mg kg-1;土壤活性指数I显示,万吨铬盐生产车间土壤的活性指数最高达到0.291 8,铬盐生产车间活性指数最低;水、盐酸、柠檬酸、Ca Cl2、Na OH、磷酸等对总铬的去除率比较低,EDTA的淋洗效果最佳;EDTA的最佳淋洗浓度为0.1 mol L-1;最适土液质量比为1∶10;最适振荡淋洗时间为1 h;最适淋洗液p H为5;所有淋洗试验最高去除率为p H 10时,北部厂区样品在0.1 mol L-1EDTA淋洗液,土液质量比为1∶10,振荡淋洗时间1 h取得,总铬的去除率可达到22%,Cr6+去除率可达到98.5%。  相似文献   

4.
刘增俊  刘红敏  夏旭  张旭  李广贺  张丹  姜林 《土壤》2016,48(3):523-528
选用连二亚硫酸钠作为修复药剂,通过正交试验,探讨了药剂量、水土比、养护时间及搅拌时间等4个因素对该药剂修复铬污染土壤效果的影响,并基于肠胃模拟方法,考察了修复前后土壤中铬的生物有效性变化,并评估其健康风险。结果表明,就铬污染土壤而言,药剂量对修复后土壤的六价铬浸出浓度影响最大,其他因素次之。达到较好修复效果的最佳修复条件为药剂量为8%、水土比为0.5、养护时间为1天、搅拌时间为15 min。药剂修复后土壤的六价铬生物有效性大幅降低,降幅为63.21%~84.67%,六价铬致癌风险降幅达81.7%,有效降低人体健康风险。  相似文献   

5.
采用室内模拟方法较为系统地研究了六价水溶态铬和总铬对土壤脲酶活性的影响。结果表明,六价铬进入土壤后,水溶态含量迅速降低,降幅随培养时间延长而减缓;水溶态铬含量与外源总铬的变化呈极显著正相关;六价铬抑制土壤脲酶活性,且脲酶活性与六价水溶态铬达到极显著负相关,揭示脲酶活性可作为土壤铬污染程度的指标之一;从土壤脲酶角度获得的红壤轻度和中度污染时临界浓度,土壤总铬和水溶态铬含量分别为17.07、85.37mg·kg-1和0.78、3.88mg·kg-1;随土壤肥力降低,土壤脲酶的ED10和ED50递减。  相似文献   

6.
研究了用0.2 mol.L-1柠檬酸/柠檬酸钠(摩尔比为1∶1)复合淋洗剂对污染土壤中铬的淋洗效果,及淋洗过程中C(rⅥ)和C(rⅢ)以及弱酸可提取态的含量随淋洗时间的变化,污染土壤取自于沈阳市沈北新区铬渣堆放场地污染土壤。结果表明,在该复合淋洗剂的解吸附与络合的双重作用下,总铬的短时间去除效率较高,淋洗8 h和24 h的去除率分别为33.6%和36.0%,其中淋洗24h时C(rⅥ)和C(rⅢ)的去除率分别达到38.5%和30.0%。淋洗过程中土壤中铬的形态发生了重新分配,弱酸可提取态占总铬比例增加,从而有利于铬在土壤中的迁移。  相似文献   

7.
锌铬复合污染对水稻不同生育期土壤酶活性的影响   总被引:5,自引:0,他引:5  
通过盆栽试验,研究了锌铬复合污染对水稻(Oryza sativaL.)不同生育期土壤酶活性的影响。结果表明,锌铬复合污染对水稻生长有抑制作用,随土壤中锌铬浓度的增加,不同生育期水稻生物量均呈下降的趋势,而根冠比呈一定的升高趋势,差异极显著(P<0.01)。在锌铬污染下,土壤过氧化氢酶活性随土壤中锌铬浓度增大而降低。与对照相比,在水稻分蘖期、孕穗期及灌浆结实期土壤过氧化氢酶活性的最小值分别降低了34.17%、23.02%和4.89%;除在灌浆结实期锌与铬浓度互作间的差异不显著外,其他生育期的锌浓度间、铬浓度间及锌与铬浓度互作间的差异均极显著(P<0.01)。在水稻分蘖期,土壤脲酶活性、转化酶活性随土壤锌铬浓度的增加而降低,但在孕穗期及灌浆结实期则升高,其差异均极显著(P<0.01)。线性回归及偏相关分析表明,在水稻不同生育期,土壤过氧化氢酶活性与土壤中锌、铬浓度均有极显著的线性回归关系,并呈显著或极显著负相关关系,这说明锌铬复合污染对土壤过氧化氢酶活性可能产生协同或加和的抑制效应。土壤脲酶活性在水稻灌浆结实期与土壤中锌浓度有极显著的线性回归关系,偏相关系数为0.7253**;土壤转化酶活性在水稻分蘖期、灌浆结实期与土壤中铬浓度均有极显著的线性回归关系,偏相关系数分别为-0.7426**、0.8056**,这说明锌铬复合污染对土壤脲酶活性及转化酶活性未产生复合效应。  相似文献   

8.
采用微波消解仪对土壤样品进行前处理,用ICAP测定土壤中总铬含量。通过硝酸-氢氟酸以及硝酸-盐酸-过氧化氢体系消解液对土壤样品消解,优化试验选择出微波最佳消解条件和ICAP的工作参数。结果表明,发现用硝酸-氢氟酸体系消解液,在谱线283.56 nm、267.72 nm处用ICAP能够准确而稳定地测得土壤中总铬含量。  相似文献   

9.
通过盆栽试验方法,选择经济作物甜菜和牧草类黑麦草、苏丹草、香根草为供试植物,研究了甜菜与3种牧草分别间作及各自单作对多环芳烃(PAHs)菲、荧蒽、芘和苯并[a]芘污染土壤修复作用。结果显示:经6个月连续两茬种植试验后,所有种植植物的处理中土壤PAHs的去除率均高于无植物种植组,间作种植土壤PAHs的去除率高于单作,黑麦草、苏丹草、香根草与甜菜间作对土壤PAHs的去除率分别达到84.85%、79.96%、84.11%;在土壤污染条件下,间作模式更有利于甜菜生长;种植植物增强了土壤中多酚氧化酶和过氧化氢酶的活性,间作模式下二者活性高于单作4.37%~43.07%,过氧化氢酶较多酚氧化酶对PAHs土壤污染更敏感,可作为关键酶用于评价土壤PAHs污染状况。在不影响农业生产的前提下,修复植物牧草和经济作物甜菜间作种植模式显著提高了土壤PAHs的降解率。  相似文献   

10.
不同改良剂对铬污染土壤中小白菜生理、生化特性的影响   总被引:3,自引:0,他引:3  
为了研究不同种类改良剂对铬污染土壤中小白菜生理生化特性的影响,采用盆栽试验监测在不同浓度的铬污染的土壤中小白菜(Brassica parichinensis)的叶绿素含量、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性以及丙二醛(MDA)含量的变化。研究发现,不同浓度的铬污染土壤中,3种改良剂添加使叶绿素含量及SOD酶活性发生变化并高于对照组而POD酶活性降低,使铬对CAT酶活性的抑制作用得到缓解。石灰、石灰+活性炭用量的增加使MDA含量先降低后升高,而活性炭的施入减少MDA的含量。通过比较,3种改良剂的改良效果为活性炭>石灰+活性炭>石灰。  相似文献   

11.
低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响   总被引:2,自引:2,他引:0  
【目的】以富士(Fuji)、 秦冠(Qinguan)嫁接在平邑甜茶(Malus hupehensis Rehd.)上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水(ZZ)、 低氮正常水(DZ)、 正常氮干旱(ZG)、 低氮干旱(DG)。氮素和水分均设置两个水平,分别为正常氮(6 mmol/L NO-3-N)、 低氮(0.3 mmol/LNO-3-N)、 正常供水(保持盆中砂子相对含水量为饱和含水量的80%~85%)、 干旱处理(保持盆中砂子相对含水量为饱和含水量的60%~65%)。【结果】富士和秦冠的生物量(茎和叶)、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水(ZZ)>低氮正常水(DZ)>正常氮干旱(ZG)>低氮干旱(DG),并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水(ZZ)>低氮正常水(DZ)>正常氮干旱(ZG)>低氮干旱(DG); 氮、 钾元素含量在植株各部位的分布顺序依次是叶>根>茎,磷元素则是根>叶>茎;光合氮素利用效率(PNUE)和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水(DZ)处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱(DG)处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。  相似文献   

12.
Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.  相似文献   

13.
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,  相似文献   

14.
Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.  相似文献   

15.
We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.  相似文献   

16.
李聃枫  朱春梧 《土壤》2020,52(3):561-566
自20世纪60年代"绿色革命"以来,育种技术和农耕技术的发展促进了农作物产量的大幅提升,然而作物的营养品质出现下降趋势。在相似的遗传背景下,大气CO_2浓度升高会使单位体积农作物产品的营养元素含量下降,因此"绿色革命"至今,农作物产品的营养元素下降可能受大气CO_2浓度升高影响。通过植物生长箱模拟"绿色革命"初期和目前的大气CO_2浓度水平(310μmol/mol和400μmol/mol),针对主要C_3作物水稻、小麦和大豆,研究"绿色革命"以来大气CO_2浓度升高对其籽粒的C、N、Fe、Zn元素含量的影响,结果表明:CO_2浓度升高对3种作物籽粒的C元素含量几乎没有影响,变化幅度在±1.5%之间;籽粒的N、Fe、Zn元素含量普遍呈现下降趋势,但均未达到显著水平。  相似文献   

17.
Discovery and incorporation of genes from wild species provide means to sustain crop improvement, particularly when levels of resistance in the cultigens are low and virulent strains of pests and pathogens overcome the host plant resistance. The extent of utilization and the potential of the wild genepool for genetic enhancement were reviewed in five important food crops viz. sorghum, pearl millet, chickpea, pigeonpea and groundnut grown in the semi-arid tropics. Introgression from compatible wild germplasm in the primary gene pool resulted in transfer of new cytoplasmic male sterility systems in pearl millet and pigeonpea, development of high protein, cleistogamous flower and dwarf pigeonpea lines and foliar disease resistant groundnut cultivars. Utilization of wild species in secondary and tertiary gene pools has been generally limited due to sterility, restricted recombination or cross incompatibility. Nevertheless, these species are extremely important as they contain high levels of resistance to several important biotic and abiotic stresses. Several of them, like those belonging to the Parasorghum section and the rhizomatous Arachis species are sources of multiple resistances and hold great promise to sustain crop productivity.  相似文献   

18.
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,  相似文献   

19.
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,  相似文献   

20.
The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.  相似文献   

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