重金属污染土壤毒性的斜生栅藻生长抑制实验诊断

应用斜生栅藻 (Scenedesmusobliquus)对重金属污染土壤的毒性进行诊断 ,结果表明 ,斜生栅藻的增长率与土壤中的重金属含量明显相关 ,并且随重金属投加量的增加 ,其增长率逐渐降低 .对两种测试参数进行比较 ,发现采用细胞数增长率作为土壤毒性的检测指标要比采用光密度增长率更为敏感 .当采用细胞数增长率作为检测指标时 ,4种重金属的EC50 顺序为 :Pb >Cu >Zn >Cd ;采用光密度增长率作为检测指标时 ,4种重金属的EC50 顺序为 :Pb >Cu >Cd >Zn .复合污染情况下 ,由于金属间的协同作用 ,使土壤的毒性比单一重金属污染时有明显增强 ,从而为污染土壤的优先修复提供了理论依据     

利用重金属超量积累植物净化被重金属污染的土壤

随着人口的增长和工业的发展,废物废水的排放和矿山废弃地不断增加,加之各种化学物质在人类活动中的广泛使用,重金属污染已成为人们日益关注的环境问题之一。土壤被重金属污染以后,一方面直接影响作物生产并通过食物链危害人类;另一方面由于大多数重金属元素进入土壤以后很难移动,使治理重金属污染的土壤变得十分困难。自然净化过程极其漫长,一般需要成千上万年的时间。采用客土法和淋溶法治理,不仅成本昂贵,需要特殊仪器和经过培训的专业人员,还不能从根本上解决问题。随着人OJ对环境保护的日益重视,一些科学家开始探索在不破…     

土壤重金属污染对蚯蚓的急性毒性效应研究

测定了草甸棕壤条件下 ,Cu、Zn、Pb、Cd单一 /复合污染对蚯蚓的急性致死及亚致死效应 .结果表明 ,Cu、Pb浓度与蚯蚓死亡率显著相关 (α=0 .0 5 ,RCu=0 .86 ,RPb=0 .87) ,Cu浓度与生长抑制率显著相关 (α=0 .0 5 ,RCu=0 .84) ,其他供试重金属浓度与蚯蚓死亡率和生长抑制率相关性不显著 .蚯蚓个体对重金属毒性的耐受程度差别较大 .其毒性阈值 (引起个体蚯蚓死亡浓度 )分别为 :Cu 30 0mg·kg-1,Zn 130 0mg·kg-1,Pb 170 0mg·kg-1,Cd 30 0mg·kg-1.LC50 分别为 :Cu 40 0～ 45 0mg·kg-1,Zn15 0 0～ 190 0mg·kg-1,Pb2 35 0～ 2 40 0mg·kg-1,Cd 90 0mg·kg-1.在Cu、Zn、Pb、Cd单一污染引起 >10 %蚯蚓死亡的浓度下 ,复合污染导致 10 0 %蚯蚓死亡 ,表明复合污染极强的协同效应 .     

株洲工业区土壤重金属污染与蚯蚓同工酶的研究

用聚丙烯朊胺凝胶圆盘电泳法对蚯蚓酯酶及过氧化物酶同工酶进行比较研究,结果表明,重金属在蚯蚓体内富集量随污染程度增加而上升,重污染区为中污染区的２．２７倍,为轻污染区的７．３０倍,重污染区Ｃｄ、Ｐｂ、Ａｓ在蚯蚓体内分别达到４７．３、３５．２、１６．３２μｇ．ｋｇ＾－１。其秩相关系数（ｒ５）〉０．６６－０．７７。蚯蚓酯酶同工酶酶带减少,酶活性降低,而其过氧化物酶酶带和酶活性有所增加。     

重金属对土壤中小麦种子发芽与根伸长抑制的生态毒性

测定了4种土壤（红壤、草甸棕壤、暗棕壤和栗钙土）条件下,Cu,Zn,Pb和Cd单一污染对小麦种子发芽与根伸长抑制主及其复合污染效应（暗棕壤条件下）。结果表明,同一浓度下,重金属对小麦根伸长抑制率均明显大于对种子发芽抑制率,植物根对金属污染的生态毒性比种子发芽敏感,土壤有机质和土壤N含量与Cu,Zn,Pb和Cd污染对小麦根伸长抑制率显著负相关（R^2OR=0.91,R^2K-N=0.92),土壤PH和阳离子交换量与Cu,Zn,Pb和Cd污染对小麦根伸长抑制率的相关性不显著（R^2PH=0.62,R^2CEC=0.60),在单一污染对小麦根伸长为刺激作用浓度（较低浓度）或为抑制作用浓度下（较高浓度）,复合污染均表现为协同作用。^     

重金属对土壤中萝卜种子发芽与根伸长抑制的生态毒性

高等植物是生态系统中的基本组成部分。一个平衡、稳定的生态系统生产健康、优良的高等植物。反之 ,一个不稳定或受到外来污染的生态系统 ,对高等植物的生长可带来不利和可见的负面影响。因此 ,利用高等植物的生长状况监测土壤污染程度 ,是从生态学角度衡量土壤健康状况 ,评价土壤质量的重要方法之一[4 ,6] 1) 。土壤生态毒理学评价方法是对化学分析方法的重要补充。目前已建立的高等植物毒理试验有三种方法 ,即 1根伸长试验 ;2种子发芽试验 ;3早期植物幼苗生长试验[3 ,5,6,10 ] 。最初 ,这类试验主要用于纯化学品的毒性检验 ,但随着对土壤…     

用植物清除土壤重金属污染

伴随着人类社会工业的发展,环境污染也越来越严重,其中土壤的污染已日益引起人们的重视。土壤污染物按其性质可分为有机污染和无机污染两种,前者包括有机农药、石油和有机洗涤剂等,后者指重金属和放射性元素等。以往人们曾经想了很多办法来治理这些污染,如客土法、淋溶法和络合浸提法等。然而应用这些方法通常需要巨额的花费,而且还容易造成二次污染。那么是否有更好的办法吗？答案是肯定的,这就是利用植物来清除土壤的污染物。以土壤重金属污染为例,有人注意到,在一些多年的煤矿以及一些工业排污区,只有少数植物可以生长,而其他…     

重金属污染对蛙蟾类毒性的研究进展

基于近20年的大量相关资料,综述了重金属对蛙蟾类毒性影响方面的研究,介绍了实验动物和实验方法,综合了重金属对蛙蟾类在形态、器官、组织、细胞和分子水平上毒害的主要表现,从重金属致毒过程、环境因素、物种、发育、重金属积累、联合毒性等角度初步分析了重金属对蛙蟾毒性大小的影响因素和毒性作用的主要机理,归纳了蛙蟾的几种抗毒/解毒/避毒反应,对开展进一步的研究提出建议.     

重金属污染土壤修复技术研究的现状与展望

目前重金属污染土壤的修复主要采用物理化学技术和植物修复技术,根据其作用和过程和机物,物理化学技术主要包括化学固化,土壤淋洗和动电修复;植物修复技术包括植物稳定,植物挥发和植物提取,本文就各种修复技术的原理,优缺点,实用性及其国际研究与发展动态作一简述。     

Bioluminescence of outer membrane defective mutants of Photobacterium phosphoreum

Abstract Mutants of Photobacterium phosphoreum NCMB7 hypersensitive to several antimicrobiol agents were independently isolated and characterized. The hypersensitivity was probably due to changes in the outer membrane (OM) structure; the electrophoretic lipopolysaccharide profile of one mutant was altered. In addition, 2 mutants exhibited elevated cell surface hydrophobicity. With respect to bioluminescence, the mutants were dim or dark, and showed strongly reduced activities of the inducible enzymes luciferase and fatty acid reductase. Our results suggest that the outer membrane is involved in the regulation of bacterial bioluminescence.     

Comparison of the toxicity of heavy metals to cabbage growth

Summary Cabbage plants were grown for 55 days with a nutrient solution containing 1 and 10 ppm of V, Cr(III), Cr(VI), Mn, Fe, Co, Ni, Cu, Zn, Cd, Hg(I), orHg(II). A comparison of the plant growth and chemical analysis revealed that Cr(VI), Cu, Cd, and Hg(II) in the solution are most toxic to the plant growth (hence detrimental to the cabbage-head formation) and Mn, Fe, and Zn are less toxic than other heavy metals, and that Mn, Zn, Co, Ni, and Cd and translocated into all the plant organs while V, Cr(III), Cr(VI), Fe, Cu, Hg(I), and Hg(II) are accumulated in the roots.     

Effects of aldehyde and internal ions on bioluminescence expression of Photobacterium phosphoreum

In a complex medium, cells of Photobacterium phosphoreum (strain 496) grow equally well with 1% and 3% NaCl, but luminescence occurs only with 3% NaCl in the medium. However, the suppression of luminescence is not attributable to the lack of luciferase; log phase cells growing in 1% NaCl will develop luminescence following a shift to 3% NaCl, which is accompanied by an increase of intracellular potassium. Tetradecanal stimulates bioluminescence in a 1% NaCl culture, and also in the presence of nalidixic acid, an inhibitor or gyrase. It is thus suggested that the suppression of luminescence in 1% NaCl or in 3% NaCl with nalidixic acid is due to a deficiency in the synthesis of intracellular aldehyde. The increase in intracellular potassium that occurs upon shifting from 1% to 3% NaCl may also relate to aldehyde synthesis gene expression via activation of gyrase, or via an increase in negative supercoiling of the chromosome. However, since an initial decrease of light intensity is still observed during culture even with the addition of tetradecanal, an additional factor related to cell density must also be involved in bioluminescence expression.Abbreviations nal nalidixic acid - nal-r nalidixic acid resistant strain     

食品中重金属的存在形态及其与毒性的关系

简要介绍了近年来有关食品中重金属形态及其毒性关系的研究进展,归纳了食品中重金属的化学形态特征、不同类型食品中重金属的存在形态、食品中重金属形态与生物有效性和毒性的关系,以及该领域中急需研究解决的问题．     

Expression of luminescence in Photobacterium phosphoreum: Na+ regulation of in vivo luminescence appearance

In Photobacterium phosphoreum strain 496, growth and luminescence in a complex medium are optimal with 3% NaCl. However, in the same medium with 1% NaCl growth is similar, but the development of bioluminescence does not occur. In cells grown to mid or late-log phase in 1% NaCl, light emission can be triggered by the addition of NaCl, but the time required for its appearance is quite long, at least 30–45 min. The synthesis of m-RNA and protein are required for the development of luminescence, but the long time interval suggests that some intermediate steps are required. The time required is not less in conditioned 3% NaCl medium.     

Performance of a membrane bioreactor used for the treatment of wastewater contaminated with heavy metals

In this work the performance of a Membrane bioreactor (MBR) was assessed for the removal of 3-15 mg/l of copper, lead, nickel and zinc from wastewater. The average removal efficiencies accomplished by the MBR system were 80% for Cu(II), 98% for Pb(II), 50% for Ni(II) and 77% for Zn(II). The addition of 5 g/l vermiculite into the biological reactor enhanced metal removal to 88% for copper, 85% for zinc and 60% for nickel due to adsorption of metal ions on the mineral, while it reduced biomass inhibition and increased biomass growth. The metal ions remaining in soluble form penetrated into the permeate, while those attached to sludge flocs were effectively retained by the ultrafiltration membranes. The average heterotrophic biomass inhibition was 50%, while it reduced to 29% when lower metal concentrations were fed into the reactor in the presence of vermiculite. The respective autotrophic biomass inhibition was 70% and 36%. The presence of heavy metals and vermiculite in the mixed liquor adversely impacted on membrane fouling.     

铅锌矿区土壤和植物重金属污染调查分析

对有色金属矿区土壤和植物重金属污染状况调查结果表明,由于遭受尾矿砂及矿毒水污染,矿区土壤极端贫瘠,土壤中Pb、Cd、Zn和Cu含量分别达764.74、4.10、372.75和95.57 mg.kg-1,重金属污染较为严重。在矿区周边有9种优势植物能够在污染土壤上定居,对Cu、Cd、Pb和Zn 4种重金属元素均有不同程度的积累,积累量均未达到超累积植物所规定的临界含量。其中的野菊花〔Dendranthema indicum(L.)Des Mou l.〕、旋鳞莎草〔Cyperusm ichelianus(L.)L ink〕、五节芒〔M iscanthus floridulus(Lab ill.)W arb.ex Schum.et Laut.〕3种植物地上部生物量较大且对某些重金属向地上部转运能力较强,对重金属污染土壤有一定的修复潜力。     

蚯蚓在重金属污染土壤生物修复中的应用潜力

综述了不同生态类型的蚯蚓的特性及其土壤生态功能;总结了其对土壤重金属富集和有效性的作用及影响重金属活化的机理,并指出目前相关的生物化学机理研究的不足及其未来研究方向.同时,文章针对蚯蚓在农业和环境领域的应用现状,提出其应用于重金属污染土壤的植物提取技术的可能性,在未来工作中应加强真实污染土壤室内模拟和田间试验研究,进一步探索筛选和繁育本地蚯蚓品种以及添加有机物等相关技术.