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961.
Two primary lead smelters and one secondary lead smelter have been active in the Socorro, New Mexico (USA) area in the last 110 years: the Billing smelter from 1883 to 1894, the Cuba Road smelter from 1881 to 1900, and Cal West from 1979 to 1984. Samples of plants and surface soil under each plant from all three sites were analysed for lead. The plants consisted of sparse grasses, cacti, creosote bush, snakeweed, mesquite and fourwing saltbush. Lead levels in the plants increased (2-440 g g–1) as the lead in the alkaline soils (25-10000 ng g–1) increased. However, the BAC (biological absorption coefficient), which is the ratio of lead content in the plant to the lead content in the soil, a measure of relative accumulation, decreased by one to two orders of magnitude, except for grasses and snakeweed. At background lead levels, there was little difference between lead in rootsversus foliage. At high lead levels, there was higher lead in roots versus foliage at the Billing and Cuba Road sites. The reverse was noted at Cal West. Because this is a recent operation, the higher lead in foliage may be due to foliar uptake. Plant growth at all sites appeared healthy.  相似文献   
962.
Summary Acanthoscelides obtectus (Say) is one of the most damaging pests of kidney beans,Phaseolus vulgaris L. worldwide. However, aromatic plants from the families Lamiaceae, Lauraceae, Myrtaceae and Poaceae can protect kidney beans by direct or delayed insecticidal effect, through increased adult mortality and inhibition of beetle reproduction (both oviposition and adult emergence). The efficiency of hydrodistillated and intact plants fromThymus vulgaris andT. serpyllum, Mentha piperata, Rosmarinus officinalis, Satureia hortensis, Eucalyptus globulus, Laurus nobilis, Origanum vulgare, andCymbopogon nardus was compared. For both extracts,Origanum vulgare had the best effect. The insecticidal effect was induced by more than the essential oils because no significant difference was noticed between distilled and intact plants extract. Inhibition of reproduction was particularly important. These results suggest that lipidic as well as non lipidic, allelochemicals, such as phenolics, or non-protein amino-acids, or flavonoids may be involved in the toxicity of aromatic plants to this beetle.  相似文献   
963.
海河流域是我国农业发展的一个重要基地,由于不合理开发利用,造成某些地区土壤出现贫瘠化、盐渍化和沙漠化,土壤缺磷也很明显.为了寻找植物对磷的需求特点以及海河流域土壤磷分布规律,可以从植物指示的角度研究不同地区不同植物磷含量特征及其差异,研究植物每年从土壤中输出和输入的磷总量,从而寻找农业生态系统磷循环规律并科学指导施肥.  相似文献   
964.
电镀废水的处理研究   总被引:4,自引:1,他引:4  
刘汉初  骆宏卫 《环境工程》1997,15(3):11-12,60
研究了含铬、铜、锌电镀废水的处理方法。用BaCl2沉淀铬后,加入Na2SO4除去多余的钡,然后用NaOH沉淀Cu2+、Zn2+,经压滤后排出清水。  相似文献   
965.
利用沉水植物治理水体富营养化   总被引:19,自引:0,他引:19  
文章论述了沉水植物的生态功能,着重介绍了富营养化水体沉水植被恢复的基础理论、限制因子、先锋物种选择研究的进展。指出针对华南地区水体富营养化生境和沉水植物特点进行相关理论和技术研究的必要性。  相似文献   
966.
To determine the status of the vegetation of ski slopes in northeastern-central Honshu, Japan, 94 plots (2×2 m) were set up on five ski areas (101–520 m elevation) which were established between 1945 and 1985 by forest clear-cutting, land modification, and seeding. Six vegetation types were recognized: five grasslands dominated byDigitaria adscendens, Miscanthus sinensis, Zoysia japonica, Festuca rubra, andPteridium aquilinum var.latiusculum, respectively, and bare areas of very low to no vegetation cover. Of the dominant species,F. rubra is the only introduced species; it does not, however, appear to persist. After the introduced grassland declinesM. sinensis or annual grasslands develop. Native plants, especially woody species, can establish inM. sinensis grassland but do not establish in the other grasslands. It is concluded that the introduction of exotic species is inappropriate to maintain ski slope vegetation, and the development ofM. sinensis grassland is desirable to promote natural revegetation.  相似文献   
967.
The approach developed by Environment Canada to assess risk to aquatic and terrestrial plants in nontarget habitats potentially exposed to pesticides evaluated for registration is described. An anonymous sample of pesticide submissions is used to illustrate the approach and to examine its merits and limitations in relation to test species, response variability, testing protocols, ecological relevance, and comparability with other regulatory agencies. Future directions are identified, particularly in relation to impending nontarget-plant testing guidelines for pesticide registration in Canada. This approach incorporates some of the latest research and developments in the field of risk assessment for plants. The novelty of this approach also lies in the use of the plant screening data routinely generated by chemical pesticide companies, which is intended to provide a maximum amount of information to evaluators at minimal increment cost to registrants. The proposed approach can serve as a basis for guideline development and modernization for other jurisdictions.  相似文献   
968.
从铜氨废液中回收铜   总被引:3,自引:1,他引:2  
分别采用化学沉淀法和电解法从电镀污泥水热合成铁氧体后过滤分离的铜氨废液中回收铜。实验结果表明:采用化学沉淀法处理铜氨废液,以体积比为1:1的盐酸调节铜氨废液pH为5.4~6.4,沉淀出碱式氯化铜固体,铜回收率在98%以上,1L铜氨废液可回收碱式氯化铜5.83g(合铜3.50g);采用电解法处理铜氨废液,在电流密度250A/m^2、电解时间5h、电解温度60℃的条件下,1L铜氨废液可回收3.54g铜粉,铜回收率超过99%,铜粉的粒径和纯度均可达到GB5246-85《电解铜粉》的要求。  相似文献   
969.
Guidelines provided by OECD and EPPO allow the use of data obtained in greenhouse experiments in the risk assessment for pesticides to non-target terrestrial plants in the field. The present study was undertaken to investigate the predictability of effects on field-grown plants using greenhouse data. In addition, the influence of plant development stage on plant sensitivity and herbicide efficacy, the influence of the surrounding vegetation on individual plant sensitivity and of sublethal herbicide doses on the biomass, recovery and reproduction of non-crop plants was studied. Results show that in the future, it might well be possible to translate results from greenhouse experiments to field situations, given sufficient experimental data. The results also suggest consequences at the population level. Even when only marginal effects on the biomass of non-target plants are expected, their seed production and thereby survival at the population level may be negatively affected.  相似文献   
970.
荒漠植物红砂研究进展   总被引:2,自引:0,他引:2  
主要综述了荒漠植物红砂的分布区及其生境、解剖学特征、种子萌发及幼苗生长影响因素、组织培养、生理生态特征、繁殖及育苗、分子生物学特性等方面的研究。简要阐述了修复和重建红砂植被的必要性,并着重研究了红砂种子萌发的影响因素及育苗技术的发展现状,在此基础上指出红砂研究中的不足之处,并对今后的研究方向提出了建议。  相似文献   
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