Plants inhabiting polygons for megapolis waste as promising species for phytoremediation

Screening of ruderal plant species inhabiting polygons for solid waste (SW) burying contaminated with heavy metals (HM). Among these plants, wood small-reedgrass (Calamagrostis epigeios L. Roth) was found; this plant is a perennial grass characterized by the highest level of HM, especially Ni, accumulation. The content of Ni was 703 mg/kg dry wt in wood small-reedgrass leaves and 346 mg/kg dry wt in its rhizomes. On the SW polygon closed 15 years ago, wood small-reedgrass produced a monoculture of high productivity (15 centner/ha), and this provided for extraction of HM moved from SW layers and maintenance of their concentrations in covering soil at the level not dangerous for plants (by 5–10 times below the threshold level). Under constant conditions, the tolerance of wood small-reedgrass seed germination to HM was established. Adult plants turned out to be tolerant to periodic mowing; they were capable of HM accumulation in above-ground organs; they also accumulated the osmorprotectant proline. It was concluded that wood small-reedgrass could be used for SW polygon recultivation and within the lawn grass mixtures for near-road lawns in cities.     

Transgenic plants for phytoremediation: helping nature to clean up environmental pollution

Phytoremediation is the use of plants to clean up environmental pollution. However, detoxification of organic pollutants by plants is often slow, leading to the accumulation of toxic compounds that could be later released into the environment. A recent publication by Doty and colleagues describes the development of transgenic poplars (Populus) overexpressing a mammalian cytochrome P450, a family of enzymes commonly involved in the metabolism of toxic compounds. The engineered plants showed enhanced performance with regards to the metabolism of trichloroethylene and the removal of a range of other toxic volatile organic pollutants, including vinyl chloride, carbon tetrachloride, chloroform and benzene. This work suggests that transgenic plants might be able to contribute to the wider and safer application of phytoremediation.     

环境污染治理领域中的植物修复技术

植物修复是利用植物的吸收和代谢功能将环境介质中的污染物进行分解、富集和稳定的过程。由于污染物的理化特性和环境行为不同,加之植物新陈代谢的各异,污染物植物修复的作用机理也不尽相同。与其它修复方法相比,植物修复技术投入低、效果好和纯自然,并对土壤功能的维护和土壤生物恢复有积极的作用。本文综述了近年来国外有关植物修复技术在污染治理领域中的研究进展,详细论述了推广应用污染物植物修复过程中应注意的几个技术关键;并就植物修复技术中存在的问题进行了讨论。总之,污染物植物修复技术的发展目前还不完善,就其更为详细具体的作用机理和商业推广的研究还需要做大量的工作。     

植物修复在抗生素污染治理中的应用研究进展

抗生素的环境污染问题日益严峻,如何对抗生素污染的水体和土壤进行有效的原位处理已然成为亟待解决的问题.植物修复是具有处理成本低、二次污染可控、易于后续处理、不破坏土壤和河流生态环境等优势的绿色、原位修复技术,已被证明是可用于抗生素污染治理的处理技术之一.因此,通过文献搜索和总结分析,作者们对植物修复在抗生素污染治理中的应...     

一种新发现的铜积累植物——密毛蕨

对铜尾矿上生长的密毛蕨(Petridium revolutum)进行了野外调查分析和温室营养液砂培实验.结果表明,密毛蕨所生长的废铜矿土壤中Cu含量平均为2 432 mg·kg^-1 DW,最高达7 554 mg·kg^-1 DW;地上部生物量平均为18.33 g·plant^-1 DW,最高达40.05 g·plant^-1 DW;地上部Cu含量平均为201 mg·kg^-1 DW,最高达567 mg·kg^-1 DW;地下部Cu含量平均为346 mg·kg^-1 DW,最高达1 723 mg kg^-1 DW;密毛蕨对Cu的转移系数平均为0.81,最高达3.88.在营养液砂培的条件下,Cu 7 mg·L^-1处理没有抑制密毛蕨地上部的生长;密毛蕨体内的Cu含量随着介质中Cu浓度的增加而显著增加,但是大部分的Cu积累在地下部.密毛蕨对Cu具有较强的忍耐和较高的积累能力,可作为修复Cu污染土壤的新材料.     

Development of a transgenic tobacco plant for phytoremediation of methylmercury pollution

To develop the potential of plant for phytoremediation of methylmercury pollution, a genetically engineered tobacco plant that coexpresses organomercurial lyase (MerB) with the ppk-specified polyphosphate (polyP) and merT-encoding mercury transporter was constructed by integrating a bacterial merB gene into ppk/merT-transgenic tobacco. A large number of independent transgenic tobaccos was obtained, in some of which the merB gene was stably integrated in the plant genome and substantially translated to the expected MerB enzyme in the transgenic tobacco. The ppk/merT/merB-transgenic tobacco callus showed more resistance to methylmercury (CH₃Hg⁺) and accumulated more mercury from CH₃Hg⁺-containing medium than the ppk/merT-transgenic and wild-type progenitors. These results suggest that the MerB enzyme encoded by merB degraded the incorporated CH₃Hg⁺ to Hg²⁺, which then accumulated as a less toxic Hg-polyP complex in the tobacco cells. Phytoremediation of CH₃Hg⁺ and Hg²⁺ in the environment with this engineered ppk/merT/merB-transgenic plant, which prevents the release mercury vapor (Hg⁰) into the atmosphere in addition to generating potentially recyclable mercury-rich plant residues, is believed to be more acceptable to the public than other competing technologies, including phytovolatilization.     

An overview of indexes to evaluate terrestrial plants for phytoremediation purposes (Review)

This paper reviews the various factors, coefficients and indexes developed to evaluate terrestrial plant performance in respect to phytoremediation.A brief list of indexes includes the Accumulation factor, Bioabsorption coefficient, Bioaccumulation coefficient, Bioaccumulation factor, Bioconcentration, Bioconcentration coefficient, Bioconcentration factor, Biological absorption coefficient, Biological accumulation coefficient, Biological concentration factor, Biological transfer coefficient, Concentration factor, Enrichment coefficient, Enrichment factor, Extraction coefficient, Index of bioaccumulation, Mobility index, Shoot accumulation factor, Soil host transfer factor, Soil-plant transfer coefficient, Soil-plant transfer factor, Transfer factor and Translocation factor.These indexes represent the result of a ratio calculation between element concentrations in plant parts to that of substrata. In other cases indexes arise from the ratio calculation of element concentrations in two distinct plant parts.In the literature different terms have been attributed to the same ratio and this often represents an overlap in terminology. On the other hand the same term corresponds to several different ratios and this could create confusion and misinterpretation in data comparison.Furthermore, the evaluation of hyperaccumulation, phytostabilization or phytoextraction of plant species is not always performed in the same way. Different plant parts are considered as well as different extraction procedures for both plant and substrata element assessment. As a consequence, a direct comparison between obtained data is not always reliable and possible.In this paper the various available indexes are reviewed, highlighting both the similarity and differences between them with the aim of helping the community in choosing the appropriate term for both data evaluation and comparison. In this author’s opinion there is no need of new terms to define indexes. I would stress the need for conformity to the original definitions and criteria.     

水体重金属污染植物修复研究进展

植物修复技术作为一种废水处理新技术,具有投资少、效果好、产出高、环境效益好等优点,现已得到迅速发展及广泛应用。介绍了水生超富集植物的3种生态类型,造成水体污染重金属元素类型,植物应答重金属污染的检测方法,并对植物修复水体重金属污染的发展前景提出展望。     

Insights into phytoremediation solutions for environmental recovery

Our environment is contaminated with organic and inorganic compounds released by anthropogenic activities that cause negative impacts on biological productivity and ecosystem sustainability and place human health at risk. Within the available remediation technologies, phytoremediation has emerged with high potential due to its reduced environmental impacts and economic costs. The research into phytoremediation has developed through a wide array of approaches, which also pertains to its inherent interdisciplinary characteristics, towards enhancing the potential of the technology for application in the field. Numerous patents present molecular solutions through which plants can be engineered to display improvements in key characteristics, such as the tolerance, uptake and accumulation of contaminants. The manipulation of plant growth and of the physico-chemical characteristics of the contaminated environments in order to enhance the remediation potential has also been the focus of several issued patents. This review attempts to highlight the most relevant patented advances in phytoremediation and to emphasise recent research efforts through which this green technology might be expected to develop into a commercially competitive alternative to other remediation methods.     

Activation analysis of human hair as a tool for environmental pollution monitoring

Recent development and uses of neutron activation techniques for human hair analyses are reviewed. The method of neutron activation analysis (NAA) appears to have the potential to be used as a tool for environmental pollution monitoring. Principally, two types of NAA procedure are in use nowadays for multielement analyses of human scalp hair. The more common of these is the method of instrumental neutron activation analysis (INAA), consisting of a single short-term (3-10 hours) exposure of hair to a beam of neutrons in a nuclear reactor, followed by two measurements of gamma-ray spectra at 2-3 days and 3-4 weeks after the end of irradiation. The following microelements can be commonly determined by this type of activation procedure: As, Au, Br, Cu, K, La, Na, Sb, Sm, Co, Cr, Cs, Fe, Hg, Rb, Sc, Se and Zn. The other of the two procedures involves the use of radiochemical separation techniques and is employed for quantitative determinations of elements that are not easily determined by INAA (Mo, Cd, Ni, etc.), or in cases where there is a need to achieve the lowest possible limits of analytical determination. The accuracy of NAA techniques is strongly dependent on the hair sampling and hair sample processing methods used. The analytical error of this method may vary within the range of 5-15%. Its applicability as a tool for monitoring the environmental pollution level is here demonstrated on an example of groups of individuals living in the areas differing by the degree of environmental pollution. The use of other biopsy materials, such as e.g. mammalian hair, for the purpose of environmental exposure monitoring is also considered in this review.     

Jasmonic acid alleviates boron toxicity in Puccinellia tenuiflora,a promising species for boron phytoremediation

Plant and Soil - Although elevated [CO2] causes an increase of photosynthesis in the short-term, this increase is often attenuated over time due to decreased photosynthetic capacity of the leaf in...     

An overview of environmental issues in Southern Africa

This paper provides an overview of some of the significant environmental problems in the Southern African region. The key problems highlighted are global warming and climate variability, loss of biodiversity, deforestation, desertification-land degradation, waste and littering, population growth, urbanization, pollution, poverty and health hazards. These problems present a challenge to governments and other players within and outside Southern Africa to seek for long-term solutions by addressing the root causes of these problems. The paper notes that although the environmental problems facing the Southern African region are being tackled at national, regional and international levels, there is more that can be done. At the national level, the different agencies and players, both within and outside government need to strengthen coordination and implementation of key interventions in different sectors in both rural and urban areas. At the African regional and international levels, there is a need to address geopolitical forces and issues that contribute to the underdevelopment of the African region. Among the major issues are poor terms of international trade, political instability, poverty, declining economic performance and international debt.     

A plant genetically modified that accumulates Pb is especially promising for phytoremediation

From a number of wild plant species growing on soils highly contaminated by heavy metals in Eastern Spain, Nicotiana glauca R. Graham (shrub tobacco) was selected for biotechnological modification, because it showed the most appropriate properties for phytoremediation. This plant has a wide geographic distribution, is fast-growing with a high biomass, and is repulsive to herbivores. Following Agrobacterium mediated transformation, the induction and overexpression of a wheat gene encoding phytochelatin synthase (TaPCS1) in this particular plant greatly increased its tolerance to metals such as Pb and Cd, developing seedling roots 160% longer than wild type plants. In addition, seedlings of transformed plants grown in mining soils containing high levels of Pb (1572 ppm) accumulated double concentration of this heavy metal than wild type. These results indicate that the transformed N. glauca represents a highly promising new tool for use in phytoremediation efforts.     

A defined substrate technology for the enumeration of microbial indicators of environmental pollution

The examination of water and other environmental sources for microbial pollution is a major public health undertaking. Currently, there are two accepted methods in use: the multiple-tube fermentation (MTF) and the membrane filtration (MF) tests. Both methods are designed to enumerate the secondary indicator group, total coliforms. Both tests suffer several inherent limitations, including a time delay of three to seven days to obtain a definitive result, the subjective nature of the test interpretation, and the inability to provide directly useful public health information. A defined substrate technology, originally used to enumerate specific bacterial species from mixtures in clinical urine specimens, was applied to water testing; the technology was constituted to enumerate simultaneously both total coliforms and the primary indicator bacterium E. coli. Examination of environmental isolates of these two classes of target microbes showed sensitivity equal to available methods, with potentially greater specificity. It was not subject to inhibition by bacteria other than the targets, grew injured coliforms, did not require confirmatory tests, and the maximum time to a positive was 24 hours. The defined substrate technology provides both regulatory and directly useful public health information.     

Membrane technology as a promising alternative in biodiesel production: A review

In recent years, environmental problems caused by the use of fossil fuels and the depletion of petroleum reserves have driven the world to adopt biodiesel as an alternative energy source to replace conventional petroleum-derived fuels because of biodiesel's clean and renewable nature. Biodiesel is conventionally produced in homogeneous, heterogeneous, and enzymatic catalysed processes, as well as by supercritical technology. All of these processes have their own limitations, such as wastewater generation and high energy consumption. In this context, the membrane reactor appears to be the perfect candidate to produce biodiesel because of its ability to overcome the limitations encountered by conventional production methods. Thus, the aim of this paper is to review the production of biodiesel with a membrane reactor by examining the fundamental concepts of the membrane reactor, its operating principles and the combination of membrane and catalyst in the catalytic membrane. In addition, the potential of functionalised carbon nanotubes to serve as catalysts while being incorporated into the membrane for transesterification is discussed. Furthermore, this paper will also discuss the effects of process parameters for transesterification in a membrane reactor and the advantages offered by membrane reactors for biodiesel production. This discussion is followed by some limitations faced in membrane technology. Nevertheless, based on the findings presented in this review, it is clear that the membrane reactor has the potential to be a breakthrough technology for the biodiesel industry.     

Transgenic mice expressing bacterial phytase as a model for phosphorus pollution control

We have developed transgenic mouse models to determine whether endogenous expression of phytase transgenes in the digestive tract of monogastric animals can increase the bioavailability of dietary phytate, a major but indigestible form of dietary phosphorus. We constructed phytase transgenes composed of the appA phytase gene from Escherichia coli regulated for expression in salivary glands by the rat R15 proline-rich protein promoter or by the mouse parotid secretory protein promoter. Transgenic phytase is highly expressed in the parotid salivary glands and secreted in saliva as an enzymatically active 55 kDa glycosylated protein. Expression of salivary phytase reduces fecal phosphorus by 11%. These results suggest that the introduction of salivary phytase transgenes into monogastric farm animals offers a promising biological approach to relieving the requirement for dietary phosphate supplements and to reducing phosphorus pollution from animal agriculture.     

白鹭作为无锡太湖地区环境污染指示生物的研究

2000年4—6月对分布在无锡太湖地区的4种要鸟中的白鹭(Egretta garzetta)行为生态学及其生境污染状况进行了调查研究．调查地白鹭主要栖息树种包括马尾松(Pnus masson±ana)、香樟树(C±nnamomum hupehanum)、麻砾树(Quercus acut±ssema)、榆树(Ulmus prm±la)和杨梅树（Myr±ca rubra)．栖息地总面积为7hm^2,白鹭总巢数为4200个,每棵树平均0．38个．白鹭的孵化期为19—21d,卵重23．9±4．0g(n=41),平均卵大小(44．5±4．1)mm×(32．6±4．9)mm(n＝41),平均窝卵数5．02(2—8)枚,平均窝雏数3．86(2—7)只,孵化成功率为84．25％．对白鹭雏鸟左右跗Zhe的测量分析表明不对称性不显著(P>0．05)．白鹭雏鸟食物较小,繁殖期间主要以小型鱼类和虾类为食．污染物分析结果表明,白鹭卵中除例外,六氯苯、六六六、环二烯类、DDTs、DDE、PCBs、Cr、Hg和Pb均检测到．食物链(底泥-食物-白鹭雏鸟)中,有机杀虫剂和重金属都逐级富集．通过与相对无污染的鄱阳湖地区比较,太湖地区和鄱阳湖地区卵样品中的DDs(包括DDT、DDE和DDD)浓度最高(超过2μg·g^1),其它污染物浓度均较小．太湖地区白鹭卵中的DDTs、Cd和Cr浓度低于鄱阳湖地区,其它污染物浓度鄱阳湖地区均低于太湖地区．经比较分析,两地样品中有机氯杀虫剂、PCBs和各种重金属浓度都未达到影响白鹭繁殖成功率的阈值．