Phytoextraction of rare earth elements in herbaceous plant species growing close to roads

The aim of study was to determine the phytoextraction of rare earth elements (REEs) to roots, stems and leaves of five herbaceous plant species (Achillea millefolium L., Artemisia vulgaris L., Papaver rhoeas L., Taraxacum officinale and Tripleurospermum inodorum), growing in four areas located in close proximity to a road with varied traffic intensity. Additionally, the relationship between road traffic intensity, REE concentration in soil and the content of these elements in plant organs was estimated. A. vulgaris and P. rhoeas were able to effectively transport REEs in their leaves, independently of area collection. The highest content of REEs was observed in P. rhoeas leaves and T. inodorum roots. Generally, HREEs were accumulated in P. rhoeas roots and leaves and also in the stems of T. inodorum and T. officinale, whereas LREEs were accumulated in T. inodorum roots and T. officinale stems. It is worth underlining that there was a clear relationship between road traffic intensity and REE, HREE and LREE concentration in soil. No positive correlation was found between the concentration of these elements in soil and their content in plants, with the exception of T. officinale. An effective transport of REEs from the root system to leaves was observed, what points to the possible ability of some of the tested plant species to remove REEs from soils near roads.     

Effects of incubation on solubility and mobility of trace metals in two contaminated soils

Much research has focused on changes in solubility and mobility of trace metals in soils under incubation. In this experiment, changes in solubility and mobility of trace metals (Pb, Cu and As) and Fe in two contaminated soils from Tampa, Florida and Montreal, Canada were examined. Soils of 30 g were packed in columns and were incubated for 3-80 days under water-flooding incubation. Following incubation, metal concentrations in pore water (water soluble) and in 0.01 M CaCl2 leachates (exchangeable+water soluble) were determined. While both soils were contaminated with Pb (1600-2500 mg kg(-1)), Tampa soil was also contaminated with As (230 mg kg(-1)). Contrast to the low pH (3.8) of Tampa soil, Montreal soil had an alkaline pH of 7.7 and high Ca of 1.6%. Concentrations of Fe(II) increased with incubation time in the Tampa soil mainly due to reductive Fe dissolution, but decreased in the Montreal soil possibly due to formation of FeCO3. The inverse relationship between concentrations of Pb and Fe(II) in pore water coupled with the fact that Fe(II) concentrations were much greater than those of Pb in pore water may suggest the importance of Fe(II) in controlling Pb solubility in soils. However, changes in concentrations of Fe(II), Pb, Cu and As in pore water with incubation time were similar to those in leachate, i.e. water soluble metals were positively related to exchangeable metals in the two contaminated soils. This research suggests the importance of Fe in controlling metal solubility and mobility in soils under water-flooded incubation.     

Growth and foliar nitrogen status of four plant species exposed to atmospheric ammonia

A chamber study was conducted to evaluate the growth response and leaf nitrogen (N) status of four plant species exposed to continuous ammonia (NH3) for 12 weeks (wk). This was intended to evaluate appropriate plant species that could be used to trap discharged NH3 from the exhaust fans in poultry feeding operations before moving off-site. Two hundred and forty bare-root plants of four species (Juniperus virginiana (red cedar), Gleditsia triacanthos var. inermis (thornless honey locust), Populus sp. (hybrid poplar), and Phalaris arundinacea (reed canary grass) were transplanted into 4- or 8-L polyethylene pots and grown in four environmentally controlled chambers. Plants placed in two of the four chambers received continuous exposure to anhydrous NH3 at 4 to 5 ppm while plants in another two chambers received no NH3. In each of the four chambers, 2 to 4 plants per species received no fertilizer while the rest of the plants were fertilized with a 100 ppm solution containing 21% N, 7% phosphorus, and 7% potassium. The results showed that honey locust was the fastest-growing species. The superior growth of honey locust among all species was also supported by its total biomass, root, and root dry matter (DM) weights. For all species there was a trend for plants exposed to NH3 to have greater leaf DM than their non-exposed counterparts at 6 (43.0 vs. 30.8%; P = 0.09) and 12 wk (47.9 vs. 36.6%; P = 0.07), and significantly greater (P 相似文献   

Influx,transport, and accumulation of cadmium in plant species grown at different Cd2+ activities

Abstract

Cadmium (Cd) has no known essential biological function, but it is toxic to plants, animals, and humans. A promising approach to prevent Cd from entering the food chain would be to select and/or create Cd‐accumulating plants to remediate contaminated soils or to develop Cd‐excluding plants to reduce Cd flow from soils into foods. The present study was undertaken to examine the differences in Cd influx, transport, and accumulation among five plant species in relation to plant tolerance to Cd toxicity. Ryegrass (Lolium perenne L.) had the least reduction in dry matter which may be due to its lowest Cd transport rate (TR) to shoots at all Cd levels among the plant species tested. White‐clover (Trifolium repens L.) was the most sensitive species to Cd toxicity, likely because of its highest Cd influx rate (IR) and high TR when plants were grown at low Cd²⁺ activity (≤8 μM). The high tolerance of cabbage (Brassica oleracea var. capitata L.) to moderate Cd toxicity (≤14 μM) appeared to be mainly due to the detoxification of Cd inside plant tissue since it recorded the highest TR and relatively high IR for Cd among the tested species. At Cd²⁺ activities up to 28 uM, the Cd uptake ratios of shoot/root for ryegrass were, on average, about 50‐fold and 27‐fold lower than that for cabbage and maize (Zea mays L.), respectively. These results showed that Cd could be easily transported into shoots of cabbage and maize, but was mainly confined to roots of ryegrass. We suggest that influx and transport rates, especially transport rate, could be used as plant physiological parameters for screening Cd‐excluding genotypes among monocotyledonous plants.     

Retrospective analysis of the age at death in two heavily polluted and two unpolluted Russian towns

Mean age at death during 1981-1999 was recorded in four small industrial towns located in the Kola Peninsula, north-western Russia. Two of these towns (Nikel and Monchegorsk) are heavily contaminated by sulphur dioxide and toxic metals (primarily Ni, Cu, Cd) emitted by large nickel-copper smelters; two other towns (Apatity and Polyarnye Zori) are nearly unpolluted. The results did not support the hypothesis that human life span is significantly shorter in the contaminated communities; moreover, mean age at death was lowest in Polyarnye Zori, the town not polluted by either sulfur dioxide or heavy metals but located close to the nuclear power plant. It seems that the impact of hazards other than pollution (both social and environmental), which are common for the populations of the investigated towns, shorten the life span so much that the contribution of pollutants to the decline in life expectancy cannot be detected. However, the relative importance of the life-shortening diseases associated with pollution may increase with the (expected) improvement of the quality of life.     

Uptake and translocation of plutonium in two plant species using hydroponics

This study presents determinations of the uptake and translocation of Pu in Indian mustard (Brassica juncea) and sunflower (Helianthus annuus) from Pu contaminated solution media. The initial activity levels of Pu were 18.50 and 37.00 Bq ml(-1), for Pu-nitrate [239Pu(NO3)4] and for Pu-citrate [239Pu(C6H5O7)+] in nutrient solution. Plutonium-diethylenetriaminepentaacetic acid (DTPA: [239Pu-C14H23O10N3] solution was prepared by adding 0, 5, 10, and 50 microg of DTPA ml(-1) with 239Pu(NO3)4 in nutrient solution. Concentration ratios (CR, Pu concentration in dry plant material/Pu concentration in nutrient solution) and transport indices (Tl, Pu content in the shoot/Pu content in the whole plant) were calculated to evaluate Pu uptake and translocation. All experiments were conducted in hydroponic solution in an environmental growth chamber. Plutonium concentration in the plant tissue was increased with increased Pu contamination. Plant tissue Pu concentration for Pu-nitrate and Pu-citrate application was not correlated and may be dependent on plant species. For plants receiving Pu-DTPA, the Pu concentration was increased in the shoots but decreased in the roots resulting in a negative correlation between the Pu concentrations in the plant shoots and roots. The Pu concentration in shoots of Indian mustard was increased for application rates up to 10 microg DTPA ml(-1) and up to 5 microg DTPA ml(-1) for sunflower. Similar trends were observed for the CR of plants compared to the Pu concentration in the shoots and roots, whereas the Tl was increased with increasing DTPA concentration. Plutonium in shoots of Indian mustard was up to 10 times higher than that in shoots of sunflower. The Pu concentration in the apparent free space (AFS) of plant root tissue of sunflower was more affected by concentration of DTPA than that of Indian mustard.     

What are the sources and conditions responsible for exceedences of the 24 h PM10 limit value (50 μg m−3) at a heavily trafficked London site?

The European Union has set limit values for PM₁₀ to be met in 2005. At Marylebone Road, London, where the traffic is heavy, the daily limit value of 50 μg m⁻³ is exceeded more than 35 times a year. A total of 185 days with daily PM₁₀ concentrations exceeding the limit value of 50 μg m⁻³ measured between January 2002 and December 2004 (data capture of 89.5%) are discussed in this paper. These exceedences were more frequent in early spring and in autumn. Concentrations have been disaggregated into regional, urban (background) and local (street) contributions. Most of the episodes of gravimetric PM₁₀ above the limit value were associated with a high regional background and very often the regional contribution dominated the PM₁₀ mass. The secondary aerosol (especially the particulate nitrate) made a major contribution to the PM₁₀ load. These situations were frequently observed when air masses came from the European mainland (showing that both emissions from the UK and other EU countries contributed to the exceedences), and less frequently with maritime air masses that have stagnated over the UK (showing that emissions from the UK alone less frequently contributed to the high regional background). However, the higher frequency of episodes breaching the limit value at the roadside site than at the rural site and the higher frequency of PM₁₀ concentrations above the limit value on weekdays show that the high regional contributions are additional to local and urban emissions. Local emissions mainly due to traffic were the second important contributor to the exceedences, while the contribution of the urban background of London was less important than the local emissions and the regional background. Applying the pragmatic mass closure model of Harrison et al. [2003. A pragmatic mass closure model for airborne particulate matter at urban background and roadside sites. Atmospheric Environment 37, 4927–4933], revealed that the regional aerosol is comprised very largely of ammonium nitrate and sulphate and secondary organic aerosol. Findings suggest that international abatement of secondary aerosol precursors may be the most effective measure to fulfil the requirements of the European Directive 1999/30/CE by lowering the regional background.     

Personal exposure of children and adults to airborne benzene in four French cities

Atmospheric concentrations of and personal exposure to benzene have been measured in four French metropolitan areas for 210 subjects over two seasons. Half of the volunteers were 6–13-year-old children. The adult subjects were non-smokers, not occupationally exposed and they live and work in the monitored areas. Measurements were performed using diffusive samplers followed by GC-FID analysis. The average values for ambient air concentrations (μg m⁻³) were: Rouen: 1.5; Île de France (Paris area): 1.6; Grenoble: 2.3 and Strasbourg: 2.6, showing that benzene concentrations in the ambient air of the four cities satisfy the requirements of the European Directive 2000/69EC of the European Parliament which stipulates a limit value of 5 μg m⁻³. However, the 48 h exposures measured were found to be between 2.7 and 3.5 times higher than ambient air concentrations. As a consequence, 60% of the subjects investigated, including children, were exposed to concentrations higher than the ambient air limit value. This work confirms that air monitoring data collected by fixed stations should be used with caution when assessing population exposure to benzene, especially given the influence of indoor sources and other polluted microenvironments where people spend part of their time.     

Relationship between heavy metals concentrations in egret species,their environment and food chain differences from two Headworks of Pakistan

Concentration of ten metals (Cd, Cr, Co, Cu, Fe, Li, Mn, Ni, Pb and Zn) were analyzed in the egg contents, prey and soil samples of little egret (Egretta garzetta) and cattle egret (Bubulcus ibis) from two Headworks to determine habitat and species-specific differences; to assess the importance of prey and habitat contamination as an exposure source for heavy metals. Concentration of Cu, Mn, Cr and Pb in egg contents, Fe, Co, Cu, Mn, Zn in prey and Fe, Co, Cu, Ni, Li in surface soils were significantly different (P < 0.05). Mean metal concentrations of Cr, Pb and Cd were relatively higher in little egret whereas Cu and Mn were higher in the egg contents of cattle egret. The mean concentrations of Cu, Mn and Zn were higher in prey samples of cattle egrets and Cr, Cd and Pb in prey samples of little egrets. In soil samples collected from little egret heronries metal concentrations were higher except Cu and Ni. Correlation Analysis and Hierarchical Agglomerative Cluster Analysis (HACA) identified relatively similar associations of metals and their source identification. Metals such as Fe, Cu, Mn, and Li were related with geochemical origin from parent rock material as well as anthropogenic input whereas Cr, Cd, Pb, Ni, Co and Zn were associated mostly with anthropogenic activities. The study suggested that eggs are useful bio-monitor of local heavy metal contamination.     

Partial solubility parameters of chlorobenzene and chlorophenol compounds at equilibrium distribution in two immiscible phases

Partial solubility parameters of chlorobenzene and chlorophenol compounds at equilibrium distribution in two immiscible phases such as soil-water system were studied. An integral distribution equilibrium equation is derived from the concept of partial solubility parameters and Flory-Hungins equation. Twelve chlorobenzenes and nineteen chlorophenols were employed in this study and their partial solubility parameters including dispersion( (δ_d),and polar van der Waals (δ_p), as well as their electron acceptor and donor solubility parameters (δ_a and δ_b) were calculated.Hildebrand's solubility parameter(δ) of the compounds was also obtained by using boiling point and formula.HPLC was performed by octadecyl-bonded phase as the stationary phase with methanol or acetonitrile as the mobile phase to determine the capacity factor k′ of all compounds for the calculation of δ_a and δ_b.     

Mapping and profile of emission sources for airborne volatile organic compounds from process regions at a petrochemical plant in Kaohsiung, Taiwan

This work surveyed five process regions inside a petrochemical plant in Taiwan to characterize the profiles of airborne volatile organic compounds (VOCs) and locate emission sources. Samples, taken with canisters, were analyzed with gas chromatography-mass spectrometry according to the TO-14 method. Each region was deployed with 24 sampling sites, sampled twice, and 240 samples in total were measured during the survey period. All of the data were consolidated into a database on Excel to facilitate retrieval, statistical analysis, and presentation in the form of a table or graph, and, subsequently, the profile of VOCs was elucidated. Emission sources were located by mapping the concentration distribution of either an individual or a type of species in terms of contour maps on Surfer. Through the cross-analysis of data, the abundant VOCs included alkenes, dienes, alkanes, and aromatics. A total of 19 emission sources were located from these five regions. The sources for alkanes stood inside first, third aromatic, and fourth naphtha cracking regions, whereas the ones for alkenes were inside two naphtha cracking regions. The sources for dienes were found inside the third naphtha cracking region alone; in contrast, the sources for aromatics were universally traced except inside the third naphtha cracking region. The measured intensity for sources mostly ranged from 1000 to 7000 ppb.     

The copper tolerance strategies and the role of antioxidative enzymes in three plant species grown on copper mine

This study was undertaken to identify the strategies and the status of antioxidant enzyme activities involved in three plant species tolerance against Cu-toxicity in copper mine. The following methods were used for evaluations in three wild type species; Datura stramonium, Malva sylvestris and Chenopodium ambrosioides. The level of chlorophyll and the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) by spectrometry, malondialdehyde (MDA) and dityrosine by HPLC and the levels of Cu in tissues and soils by atomic absorption spectrometry (AAS).

Analysis showed that total and available copper were at toxic levels for plants growing on contaminated soil (zone 1). However, there were not any visual and conspicuous symptoms of Cu toxicity in plant species. Among three species, excess copper was transferred only into the D. stramonium and C. ambrosioides tissues. The C. ambrosioides accumulated Cu in roots and then in leaves, in which the leaves chloroplasts stored Cu around two times of vacuoles. In D. stramonium most of Cu was accumulated in leaves in which the storage rate in vacuoles and chloroplasts were 42% and 8%, respectively. In zone 1, the chlorophyll levels increased significantly in leaves of C. ambrosioides with respect to the same plant growing on uncontaminated soil (zone 2). There was insignificant decrease in chlorophyll content of D. stramonium leaves, collected from zone 1 with respect to zone 2. The D. stramonium and C. ambrosioides in zone 1, both revealed significant increase in their tissues antioxidant enzyme activities in comparison with the same samples of zone 2. There was significant elevation in oxidative damage biomarkers; MDA and dityrosine, when the aerial parts of D. stramonium in zone 1 were compared with the same parts of zone 2.

We concluded that there were different tolerance strategies in studied plant species that protected them against copper toxicity. In M. sylvestris, exclusion of Cu from the roots or its stabilization in the soil restricted Cu toxicity effects. On the other hand D. stramonium and C. ambrosioides, elevated their antioxidative enzyme activities in response to cu-toxicity. In addition, the species D. stramonium accumulated excess of Cu in leaves vacuoles.     

Emissions of nitric oxide from 79 plant species in response to simulated nitrogen deposition

To assess the potential contribution of nitric oxide (NO) emission from the plants grown under the increasing nitrogen (N) deposition to atmospheric NO budget, the effects of simulated N deposition on NO emission and various leaf traits (e.g., specific leaf area, leaf N concentration, net photosynthetic rate, etc.) were investigated in 79 plant species classified by 13 plant functional groups. Simulated N deposition induced the significant increase of NO emission from most functional groups, especially from conifer, gymnosperm and C(3) herb. Moreover, the change rate of NO emission was significantly correlated with the change rate of various leaf traits. We conclude that the plants grown under atmospheric N deposition, especially in conifer, gymnosperm and C(3) herb, should be taken into account as an important biological source of NO and potentially contribute to atmospheric NO budget.     

The responses of two native plant species to soil petroleum contamination in the Yellow River Delta,China

Environmental Science and Pollution Research - Petroleum contamination is a significant environmental problem in the Yellow River Delta. The responses of two native salt-tolerant plant species,...     

The performance of three cultivars of rice grown near to, and distant from, a fertiliser plant

The effects of three cultivars, two water regimes and two rates of applying nitrogen fertilisers were tested when studying the performance of rice (Oryza sativa L.) near to, and distant from, a fertiliser plant emitting atmospherically dispersed pollutants. The atmosphere near the fertiliser plant had average daily peak concentrations of 144 and 210 microg m(-3) of SO(2) and NO(2), respectively. Growth was less near to, than at a distance from, the fertiliser plant. On average it was decreased by water stress while the effects of different amounts of nitrogen fertiliser were variable. Whilst there were a number of interactions involving nitrogen and water treatments, the most consistent were associated with the responses of the three cultivars at the two locations. The three cultivars performed similarly at the unpolluted control site, but there were major differences at the polluted site. These were most clearly exemplified by changes in the proportion of dry matter allocated to yields of grain and straw. At the unpolluted site, grain accounted for about 30% of the combined yields of grain and straw. At the polluted site, grain accounted for 1, 23 and 31% of the combined grain and straw yields of cultivars CO 43 (the most sensitive), TKM 9 and GR 3 (the most tolerant). Grain yields were closely related to numbers of filled grains per plant. At the polluted site, 98% of grains failed to develop in CO 43, whereas in GR 3, the number of panicles, and therefore the potential number of grains, was significantly enhanced.     

Regional and local influences on the nature of airborne particulate organic matter at four sites in New Jersey during summer 1981

As part of the New Jersey Project on Airborne Toxic Elements and Organic Substances, daily variations in the concentrations of three fractions of extractable organic matter (EOM) in samples of inhalable particulate matter were investigated at three urban sites and one rural site in New Jersey. During three episodes of elevated concentrations of airborne particulate matter, SO²⁻₄ and O₃, the concentrations of EOM increased by 50–100 % at all sites. Lower ratios of elemental to organic carbon and higher proportions of the acetone-soluble organic fraction of EOM, which contains more polar, oxidized hydrocarbons, were also observed at all sites during these episodes, indicating the formation of secondary particulate organic matter. Local emissions plus Northeast regional background organic aerosol were estimated to contribute about 10μg m⁻³ to the total EOM at the urban sites during these periods. The contribution of secondary organic aerosol to EOM was estimated to be 2 μg m ⁻³ and this seemed to be distributed over the New Jersey region. At the Newark site, an additional 4μg m⁻³ of secondary aerosol appeared to be locally generated.     

Trace metals in different species of mollusca, water and sediments from Taiwan coastal area

Since October 1994, a long-term program of Asia/Pacific Mussel Watch: Taiwan Regional Studies has been carried out. The results indicate that trace metal contents in mollusca varied among 30 different species and the environments (water and sediments) along the Taiwan coast. The orders of bioaccumulation of trace metals in mollusca were: Cu (over 200 microg/g), Thais clavigera > Isognomon legumen > Clibanarius rivescens > Crassostrea gigas; Zn (over 700 microg/g), Moruta granulata > C. gigas > Asiatica cypraea arabica > T. clavigera; Cd (over 5 microg/g), Trochus hanleyanus > Acanthopleura japonica > Nerita albicilla > Patella flexuosa; Pb (over 2 microg/g), P. flexuosa > C. gigas > T. hanleyanus > T. clavigera > C. gigas > Capiyulum mitella; Ni (over 10 microg/g), Meretrix lusoria > Philine sp. > Littoraria scabra > Tridacna squamosa > T. hanleyanus; Cr (over 30 microg/g), Littoraria undulata > T. hanleyanus > N. albicilla > Nerita chamaelor > M. granulata; As (over 20 microg/g), Perna viridis > L. scabra; and Sn (over 5 microg/g), P. viridis > L. undulata> C. mitella> C. gigas. Their seasonal and regional variations as well as their correlation are evaluated and discussed.     

Growth responses of crop and weed species to heavy metals in pot and field experiments

Greenhouse and field studies were performed to examine the growth responses and possible phytoremediation capacity towards heavy metals of several Brassicaceae (Brassica alba, Brassica carinata, Brassica napus and Brassica nigra) and Poaceae (durum wheat and barley). Soils used featured total concentrations of Cr, Cu, Pb and Zn largely exceeding the maximum levels permitted by the Italian laws. Different organic amendments were tested such as a compost and the plant growth-promoting rhizobacterium Bacillus licheniformis. In the greenhouse experiment, plant length, leaf area index and shoots dry matter were evaluated periodically for the Brassicaceae examined. Whereas plant length, grains production, weight of 1,000 seeds, ear fertility and tiller density were determined under field conditions at the end of the crop cycle for wheat and barley. In general, the species tested appeared to be tolerant to high heavy metal concentrations in soil, and slightly significant differences were found for all parameters considered. A marked growth increase was shown to occur for Brassicaceae cultivated on compost- and bacillus-amended contaminated soils, with respect to non-amended contaminated soils. With some exception, higher growth parameters were measured for wheat and barley plants cropped from contaminated soils in comparison to non-contaminated soils. Further, bacillus amendment enhanced the length of wheat and barley plants in both non-contaminated and contaminated soils, while different effects were observed for the other parameters evaluated.     

Effects of the arbuscular mycorrhizal fungus Glomus mosseae on growth and metal uptake by four plant species in copper mine tailings

A greenhouse experiment was conducted to evaluate the potential role of arbuscular mycorrhizal fungi (AMF) in encouraging revegetation of copper (Cu) mine tailings. Two native plant species, Coreopsis drummondii and Pteris vittata, together with a turf grass, Lolium perenne and a leguminous plant Trifolium repens associated with and without AMF Glomus mosseae were grown in Cu mine tailings to assess mycorrhizal effects on plant growth, mineral nutrition and metal uptake. Results indicated that symbiotic associations were successfully established between G. mosseae and all plants tested, and mycorrhizal colonization markedly increased plant dry matter yield except for L. perenne. The beneficial impacts of mycorrhizal colonization on plant growth could be largely explained by both improved P nutrition and decreased shoot Cu, As and Cd concentrations. The experiment provided evidence for the potential use of local plant species in combination with AMF for ecological restoration of metalliferous mine tailings.