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1.
Under the present investigation phytoremediation of mercury and arsenic from a tropical open cast coalmine effluent was performed. Three aquatic macrophytes Eichhornia crassipes, Lemna minor and Spirodela polyrrhiza removed appreciable amount of mercury and arsenic during 21 days experiment. Removal capacities of these macrophytes were found in the order of E. crassipes > L. minor > S. polyrrhiza. Translocation factor (shot to root ratio of heavy metals) revealed low transportation of metals from root to leaves leading higher accumulation of metals in root as compared to leaves of the plant. It was evident from plant tissue analysis that mercury and arsenic up take by macrophytes had deteriorated the N, P, K, chlorophyll and protein content in these macrophytes. Correlations between removal of arsenic and mercury from mining effluent and its increase in plant parts were highly significant. Results favoured selected species to use as promising accumulator of metals.  相似文献   

2.
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   

3.
《Geoderma》1986,37(2):157-174
Profile distributions of Ag and other metals (Cd, Cu and Pb) in contaminated and uncontaminated soils from west Wales, U.K. are presented. Background Ag levels were <0.1 μg Ag g−1, whilst profiles contaminated by past mining activities contained up to 9 μg Ag g−1. Silver showed a marked surface enrichment in all cases.Adsorption of AgNO3 by various soil samples was satisfactorily modelled by the Freundlich isotherm equation. Values for k (a constant related to the binding capacity) ranged between 50 and 1450. The Langmuir isotherm equation gave a less satisfactory summary of the adsorption behaviour.Radioactive 110mAg added to intact cores of an alluvial and a peat soil and subjected to leaching over one year (at the annual precipitation rate) remained in the surface layers; after this time 110mAg was not leached appreciably below 40 mm.A chemical fractionation procedure for soil Ag was applied to the contaminated soils. In soils contaminated between 80 and 150 years ago there were negligible amounts of readily exchangeable Ag; nearly half the total Ag was “residual” (i.e., solubilised only in concentrated nitric acid). The two intact soil columns still contained a considerable proportion of the 110mAg in the readily exchangeable form after one year, but most was bound in ‘acid-reducible’ or ‘oxidisable-organic’ forms.The evidence for a strong association between soil organic matter and Ag indicates that humus may control the availability of Ag in the short term and that mineral prospecting for Ag by the chemical analysis of soil humus may be a useful reconnaissance technique. Fixation in a residual fraction may be a mechanism which reduces the bioavailability of the element in the long term.  相似文献   

4.
Tailings are frequently a source of pollution in mining areas due to the spread of metals from their bare surfaces via wind or runoff water. Phytostabilization is an interesting and low-cost option to decrease environmental risks in these sites. In this study, an acidic mine tailing (pH 3?C4) located in a semiarid area in Southeast Spain and the spontaneous vegetation which grow on were investigated. Soil samples were taken to characterize metal contamination, and three plant species, Lygeum spartum, Piptatherum miliaceum, and Helichrysum decumbens, were sampled in order to determine plant uptake of metals. The rhizosphere pH of H. decumbens was measured to be 6.7, which was significantly higher than the bulk soil (pH 3). The electrical conductivity values were around 2?C5 dS m?1. Total metal concentrations in soil were high (9,800 mg kg?1 for Pb and 7,200 mg kg?1 for Zn). DTPA-extractable Zn and Pb were 16% and 19% of the total amount, respectively. The three selected plant species accumulated around 2?C5 mg kg?1 Cu in both shoots and roots. Zn concentration was 100 mg kg?1 in P. miliaceum roots. DTPA-extractable Zn was positively correlated with Zn plant uptake. These plant species demonstrated to grow well in acid tailings taking up only low concentrations of metals and therefore are good candidates to perform further phytostabilization works.  相似文献   

5.
A survey of primary colonization and succession of vegetation on various deposited substrates, littoral and shallow water areas of mining lakes and residual waters of the Lusatian lignite mining district is presented. Dumped substrates are characterized by a high acid potential which is caused by pyrite and marcasite of Tertiary origin. In the process of pyrite oxidation free mineral acids and large quantities of sulphate and bivalent iron are liberated. Residual waters are characterized by extreme acidity with pH values between 1.9 and 3.1 and by extremely high iron contents. Non-linear positive correlations are demonstrated between pH values and free mineral acids and between pH values and free carbonic acids (CO2) and bivalent iron. In aquatic, semi-aquatic and in terrestrial areas the succession of vegetation can be described by the following five main stages: stage of primary colonization and spontaneous vegetation; stage of monodominant species stands; stage of the formation of vegetation mosaics; stage of the formation of plant associations; final stage of succession. Index species of the terrestrial colonization are Corynephorus canescens and Calamagrostis epigejos, while Juncus bulbosus is the indicator species of aquatic colonization. The succession of vegetation develops in the direction of close-to-nature vegetation conditions which are typical for the heath areas of the Lusatian Lowlands.  相似文献   

6.
In April 1998, the Aznalcóllar mine tailings dam spilled 2 hm3 of slurry and 4 hm3 of acid waters into the Agrio River (affluent of the Guadiamar River). The pollutants reached the proximity of the Doñana National Park, 60 km downstream. The state of contamination of groundwaters and surface waters, from several samplings made subsequent to the spill, is described. Although the Guadiamar valley groundwaters remain contaminated, this situation cannot be attributed to the mining spill, but to the long history of pollution from mining activity at Aznalcóllar. Three zones can be distinguished: the most polluted zone, with pH values close to 4 and very high concentrations of metals (up to 18 mg/l of Al and 7 mg/l of Mn) and sulfates (up to 1263 mg/l); a second zone where pH values are higher (close to neutral) and, as a result, the concentration of metals is significantly lower; and a third zone, with pH exceeding 7, in which the concentration of metals has already fallen to normal levels but sulfate concentrations remain high (above 500 mg/l). The waters of the Agrio River present characteristics similar to those of the most-polluted groundwaters; on mixing with the waters of the Guadiamar River they are neutralized, precipitating firstly Al and then the rest of the metals. These metals remain deposited on the river-bed, where they are readily remobilized in later spates. Analysis of changes in groundwater quality shows a trend toward a lower content of Zn and the other metals in most wells.  相似文献   

7.
Abstract

It is well known that some plants can adapt to a high concentration of metals that would be lethal to other plant species and also accumulate toxic metals in their body up to a very high level (Peterson 1983). Athyrium yokoscense communities are often observed on highly polluted soils with heavy metals originating from mining or smelting facilities. A. yokoscense and some species of plants which can grow vigorously on highly polluted soils have attracted the attention of miners and investigators as indicator plants for mining areas (Honjo 1990; Nishizono et al. 1987).  相似文献   

8.
Aeromonas hydrophila densities were monitored in waters and sediments over a 1-yr period in a eutrophic Texas reservoir receiving power plant cooling waters. A. hydrophila densities were elevated in warmer waters located in the power plant cooling water plume as compared to a control station. A. hydrophila concentrations in the plume correlated well with water temperature and conductivity throughout the year. Densities at the control site were not as well correlated with temperature or conductivity. Sediment densities of A. hydrophila were also elevated at plume stations, but did not show the clear seasonal fluctuations noted in overlying waters.  相似文献   

9.
The relationships between heavy metal concentrations and physico-chemical properties of natural lake waters and also with chemical fractions of these metals in lake sediments were investigated in seven natural lakes of Kumaun region of Uttarakhand Province of India during 2003–2004 and 2004–2005. The concentrations of Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb in waters of different lakes ranged from 0.29–2.39, 10.3–38.3, 431–1407, 1.0–6.6, 5.3–12.1, 12.6–166.3, 0.7–2.7 and 3.9–27.1 μg l?1 and in sediments 14.3–21.5, 90.1–197.5, 5,265–6,428, 17.7–45.9, 13.4–32.0, 40.0–149.2, 11.1–14.6 and 88.9–167.4 μg g?1, respectively. The concentrations of all metals except Fe in waters were found well below the notified toxic limits. The concentrations of Cr, Mn, Ni, Cu, Zn, Cd and Pb were positively correlated with pH, electrical conductivity, biological oxygen demand, chemical oxygen demand and alkalinity of waters, but negatively correlated with dissolved oxygen. The concentrations of Cr, Ni, Zn, Cd and Pb in waters were positively correlated with water soluble + exchangeable fraction of these metals in lake sediments. The concentrations of Zn, Cd and Pb in waters were positively correlated with carbonate bound fraction of these metals in lake sediments. Except for Ni, Zn and Cd, the concentrations of rest of the heavy metals in waters were positively correlated with organically bound fraction of these metals in lake sediments. The concentrations of Cr, Mn, Ni, Cu and Zn in waters were positively correlated with reducible fraction of these metals in lake sediments. Except for Cd, the concentrations of rest of the metals in waters were positively correlated with residual fraction and total content of these heavy metals in lake sediments.  相似文献   

10.

Purpose

Metal mining is the main cause of soil contamination caused by heavy metals. Mine tailings and minespoils generally offer hostile environments for plant growth due to their low nutrient availability, low organic matter content, and high trace metal content. This study was carried out with the aim of characterizing the soils that have developed on the tailings from an abandoned lead and zinc mine in Galicia (NW Spain) and determining the soil factors that limit revegetation.

Materials and methods

We selected three zones: (a) the minespoils, (b) in the mining area, and (c) the settling pond, where the sludge from the flotation process was deposited. A control soil was also sampled outside of the mining area. We analyzed the physicochemical properties and metal levels in the mine spoil and soil samples we collected.

Results and discussion

The results indicate that the main physical limitations of minesoils are their low effective depth, high porosity and stoniness, while the main chemical limitations are low organic matter content and low CEC and an imbalance between exchangeable cations. These minesoils are strongly affected by high Zn and Pb levels which hinder revegetation.

Conclusions

As high concentrations of toxic trace elements and a high pH are important factors in limiting the plant growth, the restoration procedure must overcome the oxidation processes by adding organic amendments that also contribute towards fixing heavy metals or by implanting spontaneous vegetation adapted to the mine conditions, such as common broom (Cytisus scoparius) or white birch (Betula celtiberica).  相似文献   

11.

Purpose

This study investigated the extent of metal accumulation by plants colonizing a mining area in Yazd Province in Central Iran. It also investigated the suitability of these plants for phytoextraction and phytostabilization as two potential phytoremediation strategies.

Materials and methods

Plants with a high bioconcentration factor (BCF) and low translocation factor (TF) have the potential for phytostabilization, whereas plants with both BCFs and TFs >1 may be appropriate for phytoextraction. In this study, both shoots and roots of 40 plant species and associated soil samples were collected and analyzed for total concentrations of trace elements (Pb, Zn, and Ag). BCFs and TFs were calculated for each element.

Results and discussion

Nonnea persica, Achillea wilhelmsii, Erodium cicutarium, and Mentha longifolia were found to be the most suitable species for phytostabilization of Pb and Zn. Colchicum schimperi, Londesia eriantha, Lallemantia royleana, Bromus tectorum, Hordeum glaucum, and Thuspeinantha persica are the most promising species for element phytoextraction in sites slightly enriched by Ag. Ferula assa-foetida is the most suitable species for phytostabilization of the three studied metals. C. schimperi, L. eriantha, L. royleana, B. tectorum, M. longifolia, and T. persica accumulated Ag, albeit at low level.

Conclusions

Our preliminary study shows that some native plant species growing on this contaminated site may have potential for phytoremediation.
  相似文献   

12.
[目的]研究黔西某煤矿区周边土壤重金属污染情况、重金属形态潜在风险及其周边重金属富集植物,为当地的重金属污染防治提供科学依据。[方法]采用潜在生态风险评价及模糊数学法的两种评价方法(单因素决定模型和加权平均模型)对煤矿区及非煤矿区土壤进行重金属生态风险评价,对影响土壤肥力的土壤理化指标进行检测,利用风险评估编码法对重金属形态进行分析,并采用生物富集系数法对煤矿区周边富集重金属植物进行筛选。[结果]煤矿区Hg,Cd,As,Zn,Cr及Ni平均值含量分别是背景值的2.47,3.65,2.00,1.23,1.74,1.69倍。煤矿区潜在生态危害趋势为:CdHgAsNiCrPbZn。模糊数学法单因素决定模型评价显示,非煤矿区污染大于煤矿区,加权平均模型则反之。煤矿区Cd,Cr,Cu,Mn,Ni,Pb及Zn潜在风险指数分别为69.17%,7.97%,8.24%,40.10%,45.29%,53.70%及29.90%。蜈蚣草对As富集系数大于1.00,火棘、构树、盐肤木、马桑、凤尾蕨及金丝梅等对Cd富集系数大于1.00,马桑及白蒿对Pb富集系数大于1.00。[结论]煤矿区存在重金属污染,以Cd,As,Hg较为严重。煤矿区周边土壤中重金属对环境构成的潜在风险顺序为:CdPbNiMnZnCuCr。对当地而言,蜈蚣草可作为煤矿区周边修复As污染的先行植物,凤尾蕨可作为修复Cd污染的先行植物,马桑可作为修复Pb污染的先行植物。  相似文献   

13.
Mining activities generate spoils and effluents with extremely high metal concentrations of heavy metals that might have adverse effects on ecosystems and human health. Therefore, information on soil and plant metal concentrations is needed to assess the severity of the pollution and develop a strategy for soil reclamation such as phytoremediation. Here, we studied soils and vegetation in three heavily contaminated sites with potential toxic metals and metalloids (Zn, Pb, Cd, As, TI) in the mining district of Les Malines in the Languedoc region (southern France). Extremely high concentrations were found at different places such as the Les Aviniéres tailing basins (up to 160,000 mg kg?C1 Zn, 90,000 mg kg?C1 Pb, 9,700 mg kg?C1 of As and 245 mg kg?C1 of Tl) near a former furnace. Metal contamination extended several kilometres away from the mine sites probably because of the transport of toxic mining residues by wind and water. Spontaneous vegetation growing on the three mine sites was highly diversified and included 116 plant species. The vegetation cover consisted of species also found in non-contaminated soils, some of which have been shown to be metal-tolerant ecotypes (Festuca arvernensis, Koeleria vallesiana and Armeria arenaria) and several Zn, Cd and Tl hyperaccumulators such as Anthyllis vulneraria, Thlaspi caerulescens, Iberis intermedia and Silene latifolia. This latter species was highlighted as a new thallium hyperaccumulator, accumulating nearly 1,500 mg kg?C1. These species represent a patrimonial interest for their potential use for the phytoremediation of toxic metal-polluted areas.  相似文献   

14.
The distribution and mobility of heavy metals in the non-saturated zone of the alluvial plain of a wadi in the Cartagena–La Union mining district was investigated. The elemental chemistry of soils, in-depth sediments and different plant species (namely Hirsfeldia incana, Ditrichia viscosa and Piptatherum miliaceum) was carried out by using X-ray fluorescence and X-ray diffraction techniques. Potential mobility of metals was assessed by using lixiviation test runs (DIN 38414-S4). Concentrations detected in soils and sediments were higher than the acceptable limits reported in official regulations. Regarding metals mobility, values obtained for Pb, Zn and As exceed the limits established by European Union for DIN 38414-S4 leachates. Whilst the obtained leaching percentages for Pb, Cu and As were not especially high (<2%), Zn exhibit a very high leaching potential (up to 60% of the total metal content), involving potential risk of pollution events.  相似文献   

15.
Opencast coalmine effluent contains higher concentrations of Cd, Cr, Co, Ni and Pb. Biofiltration of these metals has been demonstrated successfully with the help of aquatic macrophytes i.e., E. crassipes, L. minor and A. pinnata. Experiments revealed E. crassipes reduced highest concentration of heavy metals followed by L. minor and A. pinnata on 20th days retention period. Plant tissue analysis revealed higher accumulation of metals in roots than leaves. Highly significant correlations have been noted between removal of heavy metals in effluent and their accumulation in roots and leaves of the experimental sets. Translocation factor also revealed lower transportation of metals from root to leaves. Reduction in chlorophyll and protein content was noted with the accumulation of heavy metals. N, P and K analysis in plant tissues indicated continuous decrease in their concentration with increasing metal concentration. Negative and significant correlations between metal accumulation and N, P and K concentrations in plant tissues showed adverse effects of heavy metals. Analysis of variance (Dunnett t-test) showed significant results (p?<?0.001) for all the metals in different durations.  相似文献   

16.
Role of Soil Properties in Phytoaccumulation of Uranium   总被引：1，自引：0，他引：1  
A pot study was conducted to investigate the toxiceffects of certain heavy metals on the plant growth and grainyield of wheat (Triticum aestivum L.). The resultsrevealed that heavy metals brought about significant reductionsin both parameters, Cd being the most toxic metal followed by Cu,Ni, Zn, Pb and Cr. Moreover, the presence of Cd in the soilresulted in the maximum inhibition (84.9%) in the number of freeliving Azotobacter chroococcum cells over the control. Thephytotoxicity was apparently due to the susceptibility of thefree living Azotobacter chroococcum cells to the toxicdoses of heavy metals.Protein content decreased from 19.0–71.4% in metal exposedplants at metal concentrations equivalent to those found inpolluted soil. Metal uptake by grains was directly related tothe applied heavy metal with greater concentrations of metalsfound in cases where metals were added separately rather than incombinations. The toxic effects on the plant growth, nitrogencontent in plant parts, and protein content in grains, exerted bytwo metals in combination were not additive, but rather only assevere as for the most toxic metal alone.  相似文献   

17.
Contamination of metal ions in soil and water represents more pressing threats to resources as well as human health. The present research was carried out to screen the phytosequester plants growing in industrial waste- and wastewater-affected industrial areas of Okhla, New Delhi, India. Accumulation trend of metal Fe, Zn, Cu, Cr, Pb, Cd, Hg, and As from soil and wastewater by plants were collected for study. Among aquatic plants Hydrilla verticillata, Marsilea quadrifolia, and Ipomea aquatica were found to be highest metals accumulator, Eclipta alba and Sesbania cannabina among terrestrial plant were highest accumulator of metals. Among the algal spp. Spirulina platensis and Phormidium papyraceum were the most efficient in accumulating Cd and Hg. The maximum bioconcentration factor (BCF) was recorded in Hygroryza aristata for the metals (Hg, Cd) in M. quadrifolia (Cd, Cr), in E. alba (Cr, Cu), and in S. platensis (Hg, Pb). However, the translocation factor (TF) of metals was found more in M. quadrifolia followed by I. aquatica than other plants. Among all the plants, H. verticillata showed high TF and low BCF values for toxic metals (Pb, Cr) and was suitable for phytostabilization of these metals. Our study showed that native plant species growing on contaminated sites may have a potential of phytosequestration of these metals.  相似文献   

18.
The aim of this study was to evaluate the use of metal concentrations in clam organs to monitor metal contamination in coastal sediments. The concentrations of Cd, Cr, Cu, Hg, Ni, Pb, V, and Zn were measured in the kidneys, gonads, mantles, gills, digestive gland, and hearts of the infaunal clam Amiantis umbonella collected from a contaminated site near desalination and power plant discharges, and a reference site in Kuwait Bay. Metal concentrations in sediment and sediment pore water were also measured at the collection sites of individual clams at the contaminated site. The concentrations of all metals in all organs (except Zn in the digestive gland) were significantly higher in clams from the contaminated site than from the reference site. Metal concentrations in several organs in A. umbonella from the contaminated site were correlated with those in the sediments and pore waters to which they were exposed. However, fresh weights of gonads, gills, and mantles were significantly lower in clams from the contaminated site compared to the reference site, indicating that the observed elevated concentrations of metals in the organs of clams from the contaminated site largely reflect lower organ weights, rather than higher metal loads, and that these organs in A. umbonella and perhaps other clams are not appropriate for use as biomonitors of metal contamination. Metal concentrations in clam kidneys showed a wide dynamic range with respect to environmental contamination and kidney weight was not variable. Therefore, metal concentrations in clam kidneys provide a reliable biomonitor of contaminant metals in coastal marine sediments.  相似文献   

19.
Phytoextraction is a promising technology that uses hyperaccumulating plants to remove inorganic contaminants, primarily heavy metals, from soils and waters. A field experiment was conducted to evaluate impacts of a mixture of chelators (MC) upon the growth and phytoextraction of heavy metals by the hyperaccumulator Sedum alfredii Hance in a co-planting system in a paddy soil that was historically irrigated with Pb and Zn contaminated mining wastewaters. The co-planting system used in this study was comprised of a Zn- and Cd-hyperaccumulator (S. alfredii) and a low-accumulating crop (Zea mays). Results showed that yields of S. alfredii were significantly increased with the addition of the MC and by co-planting with Z. mays. Our study further revealed that concentrations of Zn, Pb, and Cd in the corn grains of Z. mays conform to the Chinese hygiene standards for animal feeds and in the other parts of Z. mays conform to the Chinese organic fertilizer standards. The uptake of Zn, Cd, and Pb by S. alfredii was significantly increased with the addition of MC. The uptake of Zn by S. alfredii was also significantly enhanced by co-planting with Z. mays, but the interaction between MC and co-planting was not significant, meaning the effects of the two types of treatments should be additive. When the MC was applied to the co-planting system in the soil contaminated with Zn, Cd, and Pb, the highest phytoextraction rates were observed. This study suggested that the use of the hyperaccumulator S. alfredii and the low-accumulating crop Z. mays in the co-planting system with the addition of the MC was a more promising approach than the use of a single hyperaccumulator with the assistance of EDTA (ethylenediaminetetraacetic acid). This approach not only enhances the phytoextraction rates of the heavy metals but also simultaneously allows agricultural practices with safe feed products in the metal-contaminated soils.  相似文献   

20.
Forms of Cu, Ni, and Zn in the contaminated soils of the Sudbury mining/smelting district were studied to assess metal mobility and plant availability. Soil, tufted grass (Deschampsia caespitosa (L.) Beauv.), tickle grass (Agrostis scabra Willd.), dwarf birch (Betula pumila L. var. glandulifera Regel) and white birch (Betula paprifera Marsh.) leaf and twig samples were taken from 20 locations around three Cu-Ni smelters. The sampling sites were collected to cover a wide range of soil pH and soil Cu and Ni concentrations. The water-soluble, exchangeable, sodium acetate-soluble, and total concentrations of the metals in the soils were analyzed. The soils were contaminated with Cu and Ni up to 2000 µg g?1. Zinc concentrations were also elevated in some samples above the normal soil level of 100 µg g?1. The mobility of Cu and Zn, expressed as the proportion of metals in Fl and F2 forms, increased with soil pH decrease. A strong positive correlation was found between the soil exchangeable (F2) Ni and the soil pH. Concentrations of Cu and Ni in birch twigs showed a good linear relationship with exchangeable forms of the metals in soils. A highly significant correlation was also found between total Ni in soils and the metal content of the twigs. No significant correlation was found between Zn concentrations in the soils and plants. Birch twigs are a good indicator (better than leaves) of Cu and Ni contamination of the Sudbury soils. The mobile forms of Cu and Ni and low pH seem to be the main factors that will control the success of revegetation. Strong variability of the soil metal mobility requires any reclamation effort be site-specific.  相似文献   

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