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采用盆栽培育土壤的方式,通过修正的Tessier连续提取法(七步法)研究了N、P和K肥对外源Cd、Pb污染土壤重金属赋存形态的影响。结果表明,无论是原土还是添加外源性Cd、Pb的污染土壤,Pb基本被固定在残渣态和铁锰氧化物结合态,在外源Cd、Pb污染土壤中添加肥料可降低Pb的铁锰氧化物结合态等较稳定形态的赋存比例,提高生物可利用态的百分比,促进Pb向植物体系的迁移。原土中的Cd大部分处于生物可利用态,当外源性Cd污染进入土壤,离子交换态进一步增加,且土壤中Cd的浓度越大离子交换态所占的百分比越高。向中低浓度的Cd污染土加入肥料可增加离子交换态的赋存比例,提高土壤中Cd的活性;对更高浓度的Cd污染土,离子交换态已基本饱和,加入肥料对Cd的形态分布未有显著影响。添加肥料可促进土壤中外源性重金属Cd和Pb向植物体系迁移,为植物修复重金属污染土壤提供技术支持。 相似文献
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研究了金属冷、热加工工艺对Cu、Zn、Pb、As土壤粒径分布规律、种子萌发毒性及植物富集特征影响。结果表明,金属热加工造成的土壤重金属污染浓度较高,重金属在细颗粒土壤中的浓度显著高于粗颗粒土壤。金属热加工土壤Cu、Zn、Pb主要以铁锰氧化物结合态存在,As的主要形态为残渣态;金属冷加工土壤Cu的主要形态为残渣态和有机结合态,Zn、Pb主要形态为铁锰氧化物结合态,As主要形态为残渣态。冷热加工工艺不同粒径土壤培养的小麦种子发芽势和发芽率均大于80%,对种子萌发毒性较小。重金属富集量为:Zn>Cu>Pb>As,植物富集作用和重金属总量、形态分布相关。 相似文献
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以某省级工业园区及周边土壤为研究对象,对土壤重金属元素Pb、Cd、Cu、Zn、As、Cr、Ni的总量以及赋存形态特征进行了分析,并基于地理探测器、污染负荷指数法和风险编码法(RAC)对土壤重金属的生态风险进行评估,铅锌冶炼渣场及周围区域总污染负荷指数PLIZONE为1.82,属轻度污染水平。土壤中Cd以弱酸态为主,Cu以残渣态和可氧化态为主,Pb以可还原态为主,As和Cr以残渣态为主。风险评估编码法评价表明,Cd的酸提取态占比较高,可能存在风险,Cr无风险,其余重金属为低风险。地理探测器的因子探测表明高程、土壤有机质(SOM)、阳离子交换量(CEC)对7种重金属含量的解释力最显著,地势和土壤理化性质是重金属分布差异的重要影响因素。这些土壤环境因素可作为重金属含量空间预测模型的辅助变量,为土壤重金属污染防治提供科学依据。 相似文献
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生物钝化修复镉污染土壤研究进展 总被引:2,自引:0,他引:2
回顾了我国含镉土壤的场地修复。综述了利用生物钝化技术修复镉污染土壤的研究现状,重点探讨了微生物的代谢产物与镉产生硫化物或磷酸盐沉淀的微生物沉淀作用、微生物的细胞壁和其分泌的胞外聚合物直接吸附镉的微生物吸附作用以及镉离子透过微生物的细胞膜而被固定在细胞内的微生物摄取作用等生物钝化机理,并对有机钝化过程和无机钝化过程进行了介绍和评价。分析了镉在土壤中的离子交换态、碳酸盐结合态、铁锰氧化物结合态、有机结合态和残渣态等赋存形态以及土壤中pH值、氧化还原电位、有机质、共存重金属和微生物等因素对镉的生物可利用度的影响。最后阐述了生物钝化技术的优点以及该技术不能将重金属从土壤中永久去除的问题,指出生物钝化技术与其他修复方法相结合是其未来的发展方向。 相似文献
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柠檬酸对土壤中重金属形态转化的影响 总被引:1,自引:0,他引:1
重金属的存在形态对评价其对环境危害的大小具有重要意义。本文采用BCR法分级提取土壤中重金属各种形态:弱酸提取态(水溶态+可交换态+碳酸盐结合态)、可还原态(Fe-Mn氧化物结合态)、可氧化态(有机物和硫化物结合态)和残渣态,研究了柠檬酸对重金属复合污染土壤中Cd、Pb、Cr的化学形态、生物有效性的影响。结果表明随着柠檬酸量的增加,残渣态镉和铅向可还原态和可氧化态转化量也增加,残渣态铬和可还原态铬向可氧化态铬的转化量也缓慢增加,但对弱酸提取态均影响不大。说明施加柠檬酸可活化土壤中的镉铅铬,助力于植物修复技术。 相似文献
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M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria. 相似文献
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Cheng-Le Zhao Shane Porzio Alan Smith Haiyan Ge H. T. Davis L. E. Scriven 《Journal of Coatings Technology and Research》2006,3(2):109-115
Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively.
There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized.
High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without
the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of
fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to
achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic
SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve
F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender
particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing,
and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing
or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually
preserves suspension stability during freezing.
Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago,
IL. Tied for first place in The John A. Gordon Best Paper Competition. 相似文献
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Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US
In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae
and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted
in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures
(release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species
(Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species
to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were
exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of
separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles
from the southeastern region of the US. 相似文献
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Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed. 相似文献
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中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2009,37(3)
收集了2007年7月~2008年6月世界塑料工业的相关资料,介绍了2007~2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍. 相似文献
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中蓝晨光化工研究院《塑料工业》编辑部 《塑料工业》2007,35(3):1-25,67
收集了2005年7月~2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、通用热固性树脂(酚醛、聚氨酯、不饱和树脂、环氧树脂)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。 相似文献