Organ-wise accumulation of fluoride in Prosopis juliflora and its potential for phytoremediation of fluoride contaminated soil

Fluoride (F) contamination is a global environmental problem, as there is no cure of fluorosis available yet. Prosopis juliflora is a leguminous perennial, phreatophyte tree, widely distributed in arid and semi-arid regions of world. It extensively grows in F endemic areas of Rajasthan (India) and has been known as a “green” solution to decontaminate cadmium, chromium and copper contaminated soils. This study aims to check the tolerance potential of P. juliflora to accumulate fluoride. For this work, P. juliflora seedlings were grown for 75 d on soilrite under five different concentrations of F viz., control, 25, 50, 75 and 100 mg NaF kg⁻¹. Organ-wise accumulation of F, bioaccumulation factor (BF), translocation factor (TF), growth ratio (GR) and F tolerance index (TI) were examined. Plant accumulated high amounts of F in roots. The organ-wise distribution showed an accumulation 4.41 mg kg⁻¹dw, 12.97 mg kg⁻¹dw and 16.75 mg kg⁻¹dw F, in stem, leaves and roots respectively. The results indicated significant translocation of F from root into aerial parts. The bioaccumulation and translocation factor values (>1.0) showed high accumulation efficiency and tolerance of P. juliflora to F. It is concluded that P. juliflora is a suitable candidate for phytoremediation purpose and can be explored further for the decontamination of F polluted soils.     

能源植物皇草对重金属的耐性及修复潜力

重金属污染及生态修复是环境和生态领域研究的热点和难点。皇草是重要的纤维素生物燃料和电力植物。选用皇草作为重金属污染土壤的修复植物,探讨皇草对重金属的耐性机理和对重金属污染土壤的修复效果。结果表明：皇草的株高和干重在Ni、As、Zn、Pb处理中显著高于对照处理或者与对照处理没有显著差异,但在Cr处理中显著低于对照处理。皇草在Ni、As、Zn、Pb和低浓度Cr污染土壤均能生产大量的生物质,每季产25.55~28.51 t·hm-2鲜草和8.23~9.12 t·hm-2干草。皇草叶片中MDA和POD的含量随着Cr、Ni、As和Pb浓度的升高有所增加,但CAT和SOD的活性表现出相反的趋势。在Zn的2个浓度梯度下,皇草叶片中的CAT、POD和SOD的活性均随着Zn浓度升高而下降。从重金属在皇草各器官分布来看,Cr、As和Pb的浓度为根 > 叶 > 茎;Ni和Zn为根 > 茎 > 叶。从重金属在植物叶片中的形态来看,Cr、Ni、Zn和Pb的盐酸提取态的含量较高。从重金属在亚细胞分布来看,Cr、As和Pb在皇草叶片亚细胞组分分布为细胞质 > 细胞壁 > 细胞器,Ni和Zn在皇草叶片亚细胞组分分布为细胞器 > 细胞质 > 细胞壁。皇草对重金属的富集系数和转运系数均小于1,对重金属的提取量较低,但其耐性强、生物量大,适合应用于土壤重金属污染的植物稳定技术。     

Evaluation of heavy metal and polycyclic aromatic hydrocarbons accumulation in plants from typical industrial sites: potential candidate in phytoremediation for co-contamination

The heavy metal and polycyclic aromatic hydrocarbons (PAHs) contents were evaluated in surface soil and plant samples of 18 wild species collected from 3 typical industrial sites in South Central China. The accumulative characteristics of the plant species for both heavy metal and PAHs were discussed. The simultaneous accumulation of heavy metal and PAHs in plant and soil was observed at all the investigated sites, although disparities in spatial distributions among sites occurred. Both plant and soil samples were characterized by high accumulation for heavy metal at smelting site, moderate enrichment at coke power and coal mining sites, whereas high level of PAHs (16 priority pollutants according to US Environmental Protection Agency) at coke power site, followed sequentially by coal mining and smelting sites. Based on the differences of heavy metal and PAH accumulation behaviors of the studied plant species, heavy metal and PAH accumulation strategies were suggested: Pteris vittata L. and Pteris cretica L. for As and PAHs, Boehmeria nivea (L.) Gaud for Pb, As, and PAHs, and Miscanthus floridulu (Labnll.) Warb for Cu and PAHs. These native plant species could be proposed as promising materials for heavy metal and PAHs combined pollution remediation.     

Dynamics of arbuscular mycorrhizal symbiosis in heavy metal phytoremediation: meta-analytical and conceptual perspectives

To estimate dynamics of arbuscular mycorrhizal (AM) symbiosis in heavy metal (HM) phytoremediation, we conducted a literature survey and correlated HM uptake and relative plant growth parameters from published data. After estimating AM feedback responses for these parameters at low and high soil-HM concentration intervals, we determined that the roles of AM symbiosis are characterized by (1) an increased HM phytoextraction via mycorrhizospheric 'Enhanced Uptake' at low soil-HM concentrations, and (2) a reduced HM bioavailability via AM fungal 'Metal-Binding' processes at high soil-HM levels, hence resulting in increased plant biomass and enhanced plant tolerance through HM stress-avoidance. We present two conceptual models which illustrate the important compromise between plant growth, plant HM uptake and HM tolerance, and further emphasize the importance of AM symbiosis in buffering the soil environment for plants under such stress conditions.     

Comparison of heavy metal bioaccumulation in freshwater molluscs of urban river habitats in Vienna

Two bivalve species (Anodonta sp. and Unio pictorum) and two gastropod species (Radix ovata and Viviparus sp.) were tested as bioindicators in moderately metal-polluted Danube River habitats of Vienna. Molluscs, two sediment fractions and water samples were collected between April 1993 and May 1994 at six sampling sites located at five waters in Vienna. The unionid clams were dissected into viscera, gill, mantle, adductor muscle and shell, gastropods into soft body and shell. Analyses of Cd, Pb, Cu and Zn were carried out with atomic absorption spectrophotometry. Bioaccumulation of metals varied strongly according to sampling site, metal and mollusc species. Cd, Cu and Zn loads of the molluscs exceeded environmental concentrations, but not so for the apparently less bioavailable Pb. Sampling site had a significant influence on metal bioconcentrations, e.g. the Neue Donau sampling sites, where traffic emissions probably caused increased metal contents. High environmental metal concentrations in Danube harbours were poorly reflected by the bioindicator species. The gastropods showed about 20-fold higher concentrations than the bivalves. This may indicate a higher Cu regulation capacity of bivalves. The suitability of the investigated mollusc species as bioindicators depends on their specific relationship to the environmental compartment. Anodonta sp. and R. ovata concentrations were more likely related to the contents of the fine sediment fraction, which may be explained by their close association to the sediments. The metal concentrations of the deposit- and filter-feeder Viviparus sp. correlated more closely with suspended matter and filtrate contents.     

Oribatid mite communities and metal bioaccumulation in oribatid species (Acari, Oribatida) along the heavy metal gradient in forest ecosystems

The responses of oribatid communities to heavy metal contamination were studied. Concentration of cadmium, copper and zinc in nine oribatid species along a gradient of heavy metal pollution was measured. Oribatid mites were sampled seasonally during two years in five forests located at different distances from the zinc smelter in the Olkusz District, southern Poland. The most numerous and diverse oribatid communities were found in the forest with moderate concentrations of heavy metals. Analysis by atomic absorption spectrophotometry revealed large differences in metal body burdens among species. All studied oribatid species appeared to be accumulators of copper with Oppiella nova, Nothrus silvestris and Adoristes ovatus characterized by the highest bioaccumulation factors. Most species poorly accumulate cadmium and zinc. The accumulation of heavy metals in the body of oribatids was not strictly determined by their body size or the trophic level at which they operate.     

The effects of different sewage sludge amendment rates on the heavy metal bioaccumulation,growth and biomass of cucumbers (Cucumis sativus L.)

When sewage sludge is incorrectly applied, it may adversely impact agro-system productivity. Thus, this study addresses the reaction of Cucumis sativus L. (cucumber) to different amendment rates (0, 10, 20, 30, 40 and 50 g kg^?1) of sewage sludge in a greenhouse pot experiment, in which the plant growth, heavy metal uptake and biomass were evaluated. A randomized complete block design with six treatments and six replications was used as the experimental design. The soil electrical conductivity, organic matter and Cr, Fe, Zn and Ni concentrations increased, but the soil pH decreased in response to the sewage sludge applications. As approved by the Council of European Communities, all of the heavy metal concentrations in the sewage sludge were less than the permitted limit for applying sewage sludge to land. Generally, applications of sewage sludge of up to 40 g kg^?1 resulted in a considerable increase in all of the morphometric parameters and biomass of cucumbers in contrast to plants grown on the control soil. Nevertheless, the cucumber shoot height; root length; number of leaves, internodes and fruits; leaf area; absolute growth rate and biomass decreased in response to 50 g kg^?1 of sewage sludge. All of the heavy metal concentrations (except the Cu, Zn and Ni in the roots, Mn in the fruits and Pb in the stems) in different cucumber tissues increased with increasing sewage sludge application rates. However, all of the heavy metal concentrations (except the Cr and Fe in the roots, Fe in the leaves and Cu in the fruits) were within the normal range and did not reach phytotoxic levels. A characteristic of these cucumbers was that all of the heavy metals had a bioaccumulation factor <1.0. All of the heavy metals (except Cd, Cu and Zn) had translocation factors that were <1.0. As a result, the sewage sludge used in this study could be considered for use as a fertilizer in cucumber production systems in Saudi Arabia and can also serve as a substitute method of sewage sludge disposal.

The effects of different sewage sludge amendment rates on the heavy metal bioaccumulation, growth and biomass of cucumbers

     

Comparison of the heavy metal bioaccumulation capacity of an epiphytic moss and an epiphytic lichen

This study compared the heavy metal bioaccumulation capacity in the epiphytic moss Scorpiurum circinatum and the epiphytic lichen Pseudevernia furfuracea, exposed in bags for 3 months in the urban area of Acerra (S Italy). The content of Al, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Ti, V, and Zn was measured by ICP-MS. The results showed that both species accumulated all the heavy metals assayed. The moss had the highest bioaccumulation capacity for all metals and showed a more constant and linear accumulation trend than the lichen. Intra-tissue heavy metal bioaccumulation was assessed by X-ray microanalysis applied to ESEM operated in high and low vacuum and ESEM modes.     

Recent advances in physiological and molecular mechanisms of heavy metal accumulation in plants

Environmental Science and Pollution Research - Among abiotic stress, the toxicity of metals impacts negatively on plants’ growth and productivity. This toxicity promotes various perturbations...     

A comprehensive review of heavy metal pollution in the coastal areas of Bangladesh: abundance,bioaccumulation, health implications,and challenges

Environmental Science and Pollution Research - The coastal zone of Bangladesh, with a population density of 1278 people per square kilometer, is under serious threat due to heavy metal pollution....     

Integrated assessment of heavy metal (Pb, Zn, Cd) highway pollution: bioaccumulation in soil, Graminaceae and land snails

To assess the contamination induced by traffic at the vicinity of a highway (A31, France), several complementary studies were carried out on two sites, with different profiles and traffic intensity. Concentrations of zinc, lead and cadmium were measured by atomic absorption spectrophotometry in deposits, roadside soil and autochthonous plants (Graminaceae) gathered at the vicinity of the highway (1-320 m), and in the viscera of snails Helix aspersa, transferred as sentinel in the sites. According to the results obtained for different compartments, the highway induces a contamination on the surrounding environment, up to 320 m, but with the maximum contamination observed between 5 and 20 m: the concentrations measured in plants at the vicinity of the highway were 2.1 mg Pb kg(-1) DW, 0.06 mg Cd kg(-1) DW, 62 mg Zn kg(-1) DW and the concentrations measured in snails were 21.3 mg Pb kg(-1) DW, 5.7 mg Cd kg(-1) DW, 510.8 mg Zn kg(-1) DW. The levels measured decreased with increasing distance from the highway. Results of the three metals studied indicated that lead seems to be the best metal to evaluate road transport contamination.     

Accumulation of heavy metals in native Andean plants: potential tools for soil phytoremediation in Ancash (Peru)

Metal contamination is a recurring problem in Peru, caused mainly by mine tailings from a past active mining activity. The Ancash region has the largest number of environmental liabilities, which mobilizes high levels of metals and acid drainages into soils and freshwater sources, posing a standing risk on human and environmental health. Native plant species spontaneously growing on naturally acidified soils and acid mine tailings show a unique tolerance to high metal concentrations and are thus potential candidates for soil phytoremediation. However, little is known about their propagation capacity and metal accumulation under controlled conditions. In this study, we aimed at characterizing nine native plant species, previously identified as potential hyperaccumulators, from areas impacted by mine tailings in the Ancash region. Plants were grown on mine soils under greenhouse conditions during 5 months, after which the concentration of Cd, Cu, Ni, Pb, and Zn was analyzed in roots, shoots, and soils. The bioaccumulation (BAF) and translocation factor (TF) were calculated to determine the amount of each metal accumulated in the roots and shoots and to identify which species could be better suited for phytoremediation purposes. Soil samples contained high Cd (6.50–49.80 mg/kg), Cu (159.50–1187.00 mg/kg), Ni (3.50–8.70 mg/kg), Pb (1707.00–4243.00 mg/kg), and Zn (909.00–7100.00 mg/kg) concentrations exceeding national environmental quality standards. After exposure to mine tailings, concentrations of metals in shoots were highest in Werneria nubigena (Cd, 16.68 mg/kg; Cu, 41.36 mg/kg; Ni, 26.85 mg/kg; Zn, 1691.03 mg/kg), Pennisetum clandestinum (Pb, 236.86 mg/kg), and Medicago lupulina (Zn, 1078.10 mg/kg). Metal concentrations in the roots were highest in Juncus bufonius (Cd, 34.34 mg/kg; Cu, 251.07 mg/kg; Ni, 6.60 mg/kg; Pb, 718.44 mg/kg) and M. lupulina (Zn, 2415.73 mg/kg). The greatest BAF was calculated for W. nubigena (Cd, 1.92; Cu, 1.20; Ni, 6.50; Zn, 3.50) and J. bufonius (Ni, 3.02; Zn, 1.30); BCF for Calamagrostis recta (Cd, 1.09; Cu, 1.80; Ni, 1.09), J. bufonius (Cd, 3.91; Cu, 1.79; Ni, 18.36), and Achyrocline alata (Ni, 137; Zn, 1.85); and TF for W. nubigena (Cd, 2.36; Cu, 1.70; Ni, 2.42; Pb, 1.17; Zn, 1.43), A. alata (Cd, 1.14; Pb, 1.94), J. bufonius (Ni, 2.72; Zn, 1.63), and P. clandestinum (Zn, 1.14). Our results suggest that these plant species have a great potential for soil phytoremediation, given their capability to accumulate and transfer metals and their tolerance to highly metal-polluted environments in the Andean region.     

Interaction of bioaccumulation of heavy metal chromium with water relation, mineral nutrition and photosynthesis in developed leaves of Lolium perenne L

Contamination by chromium (Cr) is widespread in agricultural soils and industrial sites. This heavy metal represents a risk to human health. In order to gain fundamental insights into the nature of the adaptation to Cr excess, the characterisation of physiological indices, including responses of photosynthetic gas exchange and chlorophyll a fluorescence along with changes in mineral nutrient contents and water status were studied in ray grass (Lolium perenne L.). Increased concentrations of Cr(VI) (0-500 microM Cr) in the Co?c and Lessaint nutrient solution were applied. The growth of Lolium perenne is decreased by chromium and the leaves have lost their pigments. Chromium accumulation was greater in roots than in leaves and reached 2450 and 210 microg g(-1) DW, respectively with 500 microM Cr(VI) in nutrient medium. The physiological parameters were severely reduced by this heavy metal. Cr induced toxicity arising from 100 microM Cr(VI) and resulted in a modification of mineral content in roots and leaves, especially for Ca, Mg and Fe. The chromium stress decreased CO2 assimilation rates mainly due to stomatal closure, which reduced water loss by transpiration without decreasing the cellular available CO2. The fluorescence parameters associated with photosystem II (PSII) activity and the photochemical activity are modified by chromium. Non-radiative energy dissipation mechanisms were triggered during stress since non-photochemical quenching was increased and efficiency of excitation capture by open centers was reduced.     

橘子皮皂化改性及其对重金属离子的吸附

以农林废弃物橘子皮(OP)为原料,经氢氧化钠皂化处理,得到了改性橘子皮生物吸附剂(MOP),并将其用于对水溶液中重金属离子的吸附.研究了氢氧化钠溶液浓度、浸泡时间对改性产物产率和吸附性能的影响;通过扫描电镜、红外光谱分析,化学耗氧量、比表面积、Zeta电位的测定等方法研究了橘子皮皂化改性的机理.结果表明,橘子皮用0.2...     

一种重金属螯合剂的制备及其性能

采用聚丙烯酰胺和磺胺在碱性条件下合成了一种新型的重金属螯合剂—PAS,并对合成原料PAM和产物PAS进行了红外光谱和紫外光谱表征,分析结果表明,PAS中有N—C—S和C-S生成。将PAS用于重金属离子的螯合实验,研究了温度、pH和初始浓度对PAS去除镍离子性能的影响,用PAS处理100 mg/L的Cu2＋、Zn2＋、Cd2＋和Pb2＋的单个离子模拟废水,去除率最高分别可达到90%、96%、99%和99%。用PAS处理含Pb2＋、Cd2＋、Zn2＋和Cu2＋混合废水,去除顺序为Pb2＋〉Cd2＋〉Zn2＋〉Cu2＋。PAS对重金属离子具有很好的螯合效果,应用前景广阔。     

Reflectance properties and physiological responses of Salicornia virginica to heavy metal and petroleum contamination

Wetland ecosystems of California are located in highly populated areas and subject to high levels of contamination. Monitoring of wetlands to assess degrees of pollution damage requires periodic retrieval of information over large areas, which can be effectively accomplished by rapidly evolving remote sensing technologies. The biophysical principles of remote sensing of vegetation under stress need to be understood in order to correctly interpret the information obtained at the scale of canopies. To determine the potential to remotely characterize and monitor pollution, plants of Salicornia virginica, a major component of wetland communities in California, were treated with two metals and two crude oil types to study their sensitivity to pollutants and how this impacted their reflectance characteristics. Several growth and physiological parameters, as well as shoot reflectance were measured and correlated with symptoms and contamination levels. Significant differences between treatments were found in at least some of the measured parameters in all pollutants. Reflectance was sensitive to early stress levels only for cadmium and the lightweight petroleum. Pollutants that differ in their way of action also had different plant reflectance signatures. The high degree of correlation between reflectance features and stress indicators highlights the potential of using remote sensing to assess the type and degree of pollution damage.     

The potential of willow for remediation of heavy metal polluted calcareous urban soils

Growth performance and heavy metal uptake by willow (Salix viminalis) from strongly and moderately polluted calcareous soils were investigated in field and growth chamber trials to assess the suitability of willow for phytoremediation. Field uptakes were 2-10 times higher than growth chamber uptakes. Despite high concentrations of cadmium (≥80 mg/kg) and zinc (≥3000 mg/kg) in leaves of willow grown on strongly polluted soil with up to 18 mg Cd/kg, 1400 mg Cu/kg, 500 mg Pb/kg and 3300 mg Zn/kg, it is unsuited on strongly polluted soils because of poor growth. However, willow proved promising on moderately polluted soils (2.5 mg Cd/kg and 400 mg Zn/kg), where it extracted 0.13% of total Cd and 0.29% of the total Zn per year probably representing the most mobile fraction. Cu and Pb are strongly fixed in calcareous soils.     

Isolation and characterization of a heavy metal-resistant Burkholderia sp. from heavy metal-contaminated paddy field soil and its potential in promoting plant growth and heavy metal accumulation in metal-polluted soil

A heavy metal-resistant bacterial strain was isolated from heavy metal-contaminated soils and identified as Burkholderia sp. J62 based on the 16S rDNA gene sequence analysis. The heavy metal- and antibiotic resistance, heavy metal solubilization of the isolate were investigated. The isolate was also evaluated for promoting plant growth and Pb and Cd uptakes of the plants from heavy metal-contaminated soils in pot experiments. The isolate was found to exhibit different multiple heavy metal and antibiotic resistance characteristics. Atomic absorption spectrometer analysis showed increased bacterial solubilization of lead and cadmium in solution culture and in soils. The isolate produced indole acetic acid, siderophore and 1-aminocyclopropane-1-carboxylate deaminase. The isolate also solubilized inorganic phosphate. Inoculation with the isolate was found to significantly (p < 0.05) increase the biomass of maize and tomato plants. Increase in tissue Pb and Cd contents varied from 38% to 192% and from 5% to 191% in inoculated plants growing in heavy metal-contaminated soils compared to the uninoculated control, respectively. These results show that heavy metal-solubilizing and plant growth promoting bacteria are important for plant growth and heavy metal uptake which may provide a new microbial enhanced-phytoremediation of metal-polluted soils.     

Zinc tolerance and accumulation in Pteris vittata L. and its potential for phytoremediation of Zn- and As-contaminated soil

A field investigation and pot experiments were conducted to determine the potential of arsenic (As) hyperaccumulator, Pteris vittata L., to remediate sites co-contaminated with zinc (Zn) and As. We found that P. vittata L. had a very high tolerance to Zn and grew normally at sites with high Zn concentrations. In addition, P. vittata L. could effectively take up Zn into its fronds, with a maximum of 737 mg kg(-1) under field conditions. In pot experiments, the accumulated Zn concentration increased significantly as the Zn treatment was raised from 0 to 2000 mg kg(-1), with a maximum Zn accumulation of 0.22 mg pot(-1). Although the concentration of As in P. vittata L. was reduced by the addition of Zn, total frond accumulation of As was elevated when the Zn treatment was increased from 0 to 1000 mg kg(-1), with a maximum As accumulation of 8.3 mg pot(-1) in the presence of 1000 mg kg(-1) Zn. The high Zn tolerance, relatively high ability to accumulate Zn, and great capacity to accumulate As under conditions of suppression by high Zn suggest that P. vittata L. could be useful for the remediation of sites co-contaminated with Zn and As.     

Evaluating the distribution and potential ecological risks of heavy metal in coal gangue

Environmental Science and Pollution Research - The heavy metals, which derived from accumulated coal gangue, are important source of environmental pollution. In this study, coal gangue dumps,...