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131.
砷污染土壤的生物修复研究进展 总被引:8,自引:0,他引:8
土壤As污染已是全球性问题,我国也不例外,对As污染土壤的生物修复已是研究热点,但相关机理仍不完全清楚.本文综述了国内外微生物、蚯蚓、植物在As污染土壤中吸收转化As及其解As毒机理,以及微生物-植物复合系统修复As污染土壤方面实验室内研究情况.目前广泛认为植物修复土壤重金属/非金属污染较有应用前景,可限于甚至是使用超富集植物单一作用下仍有较多缺陷,如通过微生物技术及蚯蚓调节根际微生态,以利于植物在污染土壤中存活或/和吸收更多的As,将极具应用前景. 相似文献
132.
黄土高原砒砂岩区河岸带沙棘林营造与管护技术的研究 总被引:2,自引:2,他引:0
黄土高原砒砂岩区立地条件恶劣,河岸带是该地区具有特殊生态功能的组成部分,在河岸带种植沙棘Hippophae rhamnoides对于改善当地生态环境具有理论和现实的意义。总结几年来在该地营造与管护沙棘林的研究成果与实践经验,能够更好地为实施植被措施改善恶劣地区的生态环境奠定理论和实践基础。具体总结为:因地制宜,科学布设;选择良种壮苗,确保成活率;选择合理季节,抢墒保墒种植;保持苗木活力,搞好假植和保护;认真整地种植,确保造林质量;搞好抚育管理,保证可持续发展。同时对存在的生物多样性、林分抚育管理、病虫害防治问题进行了探讨。 相似文献
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134.
《Communications in Soil Science and Plant Analysis》2012,43(22):2837-2846
Soybean (Glycine max L.) cropping is increasing in marginal environments, including water-limited lands, some of which are loaded with arsenic (As). Plants inoculated with mycorrhiza increased their tolerance to water stress. We studied the effect of a sudden and severe water stress on soybean inoculated with the mycorrhizal fungus Glomus intraradices in soils with increasing concentrations of As. Soybean plants were grown in greenhouse with adequate water supply for 60 days. Irrigation was stopped completely and soil abruptly reached the permanent wilting point. Most inoculated plants survived under such limiting water stress, but noninoculated plants were clearly affected. Arsenic showed a negative effect on plant growth but improved plant survival under this severe water stress. It seems that the negative effects of As on plant water equilibrium explain why plants affected by As survived extreme water stress events. 相似文献
135.
以K326为供试品种,通过外加重金属及砷污染,明确不同组合及浓度处理下烟叶重金属及砷残留量及日暴露量,在初步建立烟叶重金属残留计算公式的基础上,结合世界卫生组织(WHO)推荐的食品污染物的每日允许摄入量进行相关分析,初步制定(以人体对重金属的吸收有1%来源于卷烟制品的消费计算)烟叶重金属限量标准为Cd<0.2143mg/kg,Hg<0.1143mg/kg,Pb<15.00mg/kg,As<0.857mg/kg。 相似文献
136.
磷影响下根际无机砷的形态分布及其对水稻生长的影响 总被引:16,自引:1,他引:16
两种有代表性的紫色土的水稻盆裁试验结果表明,磷的加入可减轻受砷污染的红紫泥中砷对水稻的毒害;但磷的加入会加剧受砷污染的红棕紫泥中砷对水稻的毒害。根际无机砷的形态分布研究表明:试验土壤上,根际砷各形态都比非根际高,砷在根际呈富集状态;在根际环境的作用下,红紫泥中,磷的加入加剧了砷由有效态砷(Al-As、Fe-As)向相对无效态砷(O-As)转化,砷对水稻的毒性减弱;红棕紫泥中,磷的加入加剧了砷由相对无效态砷Fe-As和Al-As向有效态砷Ca-As和A-As(表示水溶态砷及松结态砷)的转化,砷对水稻的毒性增强。 相似文献
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138.
We studied the behavior of the trace elements (TE) As, Cu, Pb and Zn associated with sulphide minerals in tailings of different age at the Guanajuato mining district, Mexico. The objective was to determine the dominant fractions into which the TE move as tailings age and to identify how much time is needed until the dominant metal fractions approach equilibrium. We collected 21 samples from the surface of mine waste deposits of different ages (0, 2 , 4, 16, 70, 75, and 100 years), and measured their aqua regia extractable contents of As, Cu, Pb and Zn. We also applied a sequential extraction procedure to quantify water soluble TE as well as TE associated with carbonates, iron oxides, sulphides and the residual fraction. The mineralogy was analysed by X-ray diffraction, and selected samples were studied on polished specimens through a stereoscopic microscope. The TE in samples extracted with aqua regia ranged between 10 and 168 mg kg− 1 for As, 12 to 194 mg kg− 1 for Cu, 31 to 308 mg kg− 1 for Pb, and 122 to 1129 mg kg− 1 for Zn, and varied in a wide range within each age group of tailings. Water soluble Cu, Pb and Zn contents were below detection limits in almost all samples, which was attributed to the alkaline pH (7.17 to 8.61) in the tailings. Water extractable As was detected only in tailings older than 16 years, and concentrations ranged between 0.06 and 7.58 mg kg− 1. The proportion of TE associated with sulphides decreased in the tailings as they age, while the proportion of TE associated with iron oxides increased with time of exposure to the atmosphere, approximating equilibrium after 60 years for As, Cu and Zn, and after 40 years for Pb. Observations of polished specimens suggests that oxidation proceeds until coatings of secondary minerals cover and protect sulphide mineral grains from further weathering. First order rate equations were adjusted to the proportions of TE associated with either sulphides or iron oxides. Assuming that the TE in sulphide fractions correspond to arsenopyrite (FeAsS), chalcopyrite (CuFeS2), galena (PbS) and sphalerite (ZnS), the relative oxidation rate of sulphides followed the order: PbS > ZnS > FeAsS ≈ CuFeS2, while the relative affinity of the elements with iron oxides followed the sequence Cu ≈ Zn > As > Pb. 相似文献
139.
140.
José Antonio Carrasco Eloísa Pajuelo Araceli Burgos Rafael López Antonio J. Palomares 《Soil biology & biochemistry》2005,37(6):1131-1140
After the toxic spill occurred at Aznalcóllar pyrite mine (Southern Spain), a wide area of croplands near the Doñana Wild Park was contaminated with 4.5 million m3 of slurries composed of acidic waters loaded with toxic metals and metalloids such as As, Sb, Zn, Pb, Cu, Co, Tl, Bi, Cd, Ag, Hg and Se. Today, 6 years after the spill, the concentration of toxic elements in these soils is still very high, in spite of the efforts to clean the zone. However, some plant species have colonised this contaminated area. Legumes possessing N2-fixing nodules on their roots represented a significant proportion of these plants. Our objective was to use the Rhizobium-legume symbiosis as a new tool for bioremediate the affected area. We have isolated about 100 Rhizobium strains, 41 of them being resistant to high concentrations of As (300 mg l−1), Cu (100 mg l−1) and Pb (500 mg l−1). Their phenotypes and bioaccumulation potentials have been characterised by their growth rates in media supplemented with As and heavy metals. The presence of the resistance genes in some strains has been confirmed by PCR and Southern blot hybridisation. Several Rhizobium were symbiotically effective in the contaminated soils. On the other hand, the first steps in nodule establishment seemed to be more affected by heavy metals than N2-fixation. 相似文献