Heavy metal in leaves of twelve plant species from seven different areas in Shanghai,China

Concentrations of heavy metals (Cu, Zn, Pb and Cd) were measured in leaves of twelve plant species from seven different locations in Shanghai, China. Unwashed and washed new and old leaves were considered, and the correlations among the heavy metal concentrations in soils and in plant leaves and deposited by the atmosphere were analyzed. In addition, scanning electron microscopy (SEM) was used to determine the stomatal density and structure of the leaves.The background site (Chenshan Botanical Garden) had lower mean metal concentrations than the other sites. The highest Cu contents were found in Nerium indicum and Platanus acerifolia, the highest Zn content was found in Pittosporum tobira, and the highest Pb and Cd contents were found in Cedrus deodara. The lowest heavy metal contents were found in Ginkgo biloba, potentially because Platanus acerifolia and Pittosporum tobira leaves have higher densities of stomata than on Ginkgo biloba leaves (according to SEM results). However, Magnolia grandiflora had the highest metal accumulation index (MAI) (4.27), and Cedrus deodara had the lowest MAI (1.53). When comparing the heavy metal contents in the washed leaf samples with the unwashed leaf samples, Nerium indicum captured more rare-earth elements (determined using the capture rate (CR)), including Cu (92.7%) and Zn (36.9%). Magnolia grandiflora had higher CR values for Pb (63.4%) and Cd (49.1%), and Cedrus deodara had lower CR values for Cu (0), Zn (8.90%), Pb (5.93%) and Cd (2.97%). In addition, the Cu, Zn, Pb and Cd in plant needles potentially originate from the soil, and the Cu, Zn, Pb and Cd in the leaves of broad-leaved plants potentially originate from bulk atmospheric deposition. This hypothesis is supported by the relationship between the heavy metal concentrations in the soils and the washed new and old leaves. In addition, the concentration factor (CF) of heavy metals supported this model.     

Sewage sludge and refuse composts as peat alternatives for conditioning impoverished soils: Effects on the growth response and mineral status of Petunia grandiflora

A glasshouse pot experiment is described comparing the growth reponse, nutritional , status and heavy metal content of Petunia grandiflora in an impoverished acid sandy soil amended with peat or composted sewage sludges and refuse. The composts consistently out-performed peat as soil améliorants because of greater nutrient availability. However, results indicated that rates of application of composts to soil should be adjusted according to the conductivity of the applied material and the salt tolerance characteristics of the plant species to be grown to avoid detrimental effects on plant growth. There were no phytotoxic effects on plant growth due to contamination of the composts with heavy metals irrespective of the level of incorporation into soil, indicating that proposed lower metal limits for composts compared with sewage sludge would be unnecessarily restrictive to compost use. Composted sewage sludges and refuse are shown to have considerable potential for use in the amenity and landscape industry for improving impoverished soils.     

Effects of Sewage Sludge Amendment on Some Soil Properties,Growth, Yield and Nutrient Content of Raspberry (<Emphasis Type="Italic">Rubus idaeus</Emphasis> L.)

This study was focused not only at the assessment of effects of different sewage sludge application rates on vegetative parameters and yield of raspberry (Rubus ideaus L.) but also heavy metal accumulation in the soil and raspberry leaves. A three-year field study was set up in a completely randomized block design with five sewage sludge application rates (0.0, 2.5, 5.0, 7.5 and 10.0?kg of dry matter per plant) and three replications. One-year-old, virus free ‘Heritage’ saplings were used for the experiment. The results of this study clearly indicated that the sewage sludge application is an effective mean for improvement of vegetative growth, yield, soil and plant chemical properties of raspberry in light textured soils. In addition to macro-element contents, sewage sludge application also caused significant changes in micro-element content of soils. No adverse effects of these increases were observed on plants throughout the experimental period. The most effective application rate was found as 7.5?kg per plant for this ecological condition. It can be concluded that when properly treated and applied to farmland sewage sludge is not only disposed economically but also improved vegetative growth and yield of raspberry.     

A comparison of the application of different waste products to a lettuce crop: Effects on plant and soil properties

A romaine-type lettuce (Lactuca sativa L.) was cultivated during three successive crop seasons in an agricultural land near the Wastewater Treatment Plant (WWTP) of Alcázar de San Juan. Four fertilization treatments were compared, including: two different organic fertilizer treatments consisting of (i) air-dried sewage sludge (SS), and (ii) municipal solid waste compost (MSWC), (iii) an inorganic treatment of commercial fertilizer (FER), and (iv) a control treatment in which no fertilizer was applied (CONT). The highest yield was observed in the SS treatment in all crop seasons. In the organic treatment plots there was an increase in macronutrients and organic matter in the soil. An accumulation of heavy metals in the soil was not observed but there was an increase in microbial population in the organic treatment plot, especially in the SS treatment plot. In plant tissue, the continued addition of fertilizers did not produce an accumulative effect of macro- and micronutrients. Low heavy metal content (Cr, Cd, Pb and Hg) was observed in all treatments and crop seasons. Microbiological content was more numerous in the first crop season in SS-treated plants, mainly in lettuce leaves but also in the soil.     

Vector analysis in the study of the nutritional status of Philodendron cultivated in compost-based media

Compost (CP) made from 70% ligno-cellulosic compounds and 30% sewage sludge was studied as a component of growing media in a 6-month Philodendron cultivation. CP's agronomic viability was evaluated via four plant-growth media containing 25–50–75–100% CP and white sphagnum peat (WP) in comparison to a commercial substrate with white and black peat. Plant nutrition conditions were investigated by determining macro- (TKN, P, K, Ca, Mg and micronutrients (Mn, Fe, Cu, Zn, Na) and heavy metals (Ni, Cd, Cr, Pb) in roots and shoot tissues. Data were compared by vector analysis against control. Even if no leaf injuries were visible after 6-months’ growth, a CP ratio of up to 50% caused growth depression of canopy tissues, as attested by the 37 and 36% reduction in total leaf dry weight and leaf area, respectively. Root growth decline was also notable at 25% CP, where 38% root dry weight reduction implied a significant increase (46%) in shoot–root dry weight ratio. The investigation on nutrient tissue content showed high accumulation of Ni, Fe, Cr, Zn, Cd, Mn, Mg and P in roots; Mg appeared related to K deficiency. Above-ground nutritional status showed a severe lack of P, Mg and Mn. Vector analysis suggests the sewage sludge CP in Philodendron pot cultivation produces many such effects like direct toxic action and antagonistic action, resulting in a general nutrient imbalance in plants.     

微生物对煤矿区适生植物污染修复的作用

为了加快污染矿区生态环境的修复,为煤矿区的污染复垦提供优势的植物资源。采用盆栽土配方法,将微生物与煤矿区适生植物进行组合,研究其生态效应。结果表明:接种VA菌根能提高荠菜、鬼针草、苍耳等植物的株高和生物量,促进煤矿区适生植物对土壤Cd、Cr、Cu、Ni、Pb等重金属的吸收,提高了荠菜、鬼针草和苍耳的重金属修复效果。     

Effect of different rates of composted organic amendment on urban soil properties,growth and nutrient status of three Mediterranean native hedge species

Increasing green space, especially in densely built-up areas is considered to be a valuable climate change adaptation response in order to reduce the threat of high temperatures to human health and comfort and to controlled global greenhouse gas emissions. Practical responses to climate change, under urban conditions, in order to avoid or reduce trees and shrubs vulnerability, can be considered drought resistant planting approaches, as the addition of organic amendeds to soil. The improvement of physical–chemical soil quality is a key step for carrying out xeriscaping programs of urban green spaces in Mediterranean semiarid areas. Organic amendments, particularly compost, have been receiving a renewed attention not only in horticulture but also in the context of restoring disturbed urban soils to address environmental issues as well as to improve trees and shrubs growth. The influence of increasing rates (0, 15, 30, and 45%) of composted sewage sludge (SSC) placed in the plantation hole on both urban soil properties and growth for three native Mediterranean woody hedge species was monitored over a 2-year period after planting. The experiment was supported by a xerogardening project in an urban context under semi-arid conditions. The results indicate that the urban soil physical characteristics were positively influenced by the addition of SSC: the 45% rate showed an increase in both moisture and infiltration values, thereby increasing the volume of plant-available water in the soil. The chemical properties of the amended soils were also directly affected by the SSC rate, but the effect of the compost on organic matter, nitrogen and potassium contents decreased over time. Our results prove that the hedge growth response to the compost treatments is also highly dependent on the rate of compost used. At the end of the trial, in Rhamnus and Myrthus plants 30% compost level guarantees the best performance; in fact, the further addition of 15% of compost led to a significant decrease in hedge and diameter values, in particular in Myrtle. This could be explained by the high pH at 45% compost, which would seem not to suit the physiology of the two species. On the other hand, in Phillyrea plants, the rate of 45% compost gives high performance equal to that of 30%; it would therefore seem that the high pH at 45% compost does not influence the nutritive elements’ absorption and, as a consequence, the growth. The use of composted sludge as an amendment for sclerophyllous could be feasible and, what is more, helpful to mitigate the environmental impact of organic waste disposal. Moreover more natural vegetation can be introduced into urban parks and green spaces in semi-arid environments to encourage sustainable landscaping and xerogardening.     

石楠和大叶黄杨对污泥基质中重金属的吸收与富集特征

运用不同配比的污泥基质进行盆栽试验,通过测定污泥、石楠和大叶黄杨不同部位的6种重金属含量,研究了石楠和大叶黄杨的重金属含量和富集特征。结果表明:随着栽培基质中污泥组成的变化,石楠和大叶黄杨中重金属含量与富集系数均没有呈现出有规律变化。2种植物根、茎、叶的重金属含量中均以Zn最高,根以Cd最低,茎和叶都以As最低。大叶黄杨根中6种重金属和叶片中Zn含量均显著高于石楠。在石楠中,As的含量根茎叶;Cd和Pb呈根显著低于茎与叶;根中Cu和Cr显著高于茎与叶;茎部Zn含量显著低于根与叶。在大叶黄杨中,As和Cu的含量均呈根茎叶;Cd在根、茎、叶之间无规律性,根中Cr含量高于茎与叶;茎部Pb含量高于根与叶;叶片中Zn含量低于根与茎。2种植物根、茎、叶对Cr与As富集能力均很低,而根对Cu、茎和叶对Pb富集能力很强。大叶黄杨根对6种重金属、茎对Zn与Pb的富集能力均显著高于石楠。2种植物对Cr和As的富集能力弱,而对Pb和Cd的富集能力强;大叶黄杨富集重金属能力高于石楠。     

Translocation of heavy metals to tomato (Solanum lycopersicom L.) fruit irrigated with treated wastewater

A field experiment was conducted to investigate the extent of translocation of heavy metals to tomato (Solanum lycopersicom L. cvs. “GS₁₂” and “RS₅₈₉₉₅₆”) fruit produced in an open field near to Abu-Nusiar Wastewater Treatment Plant, Amman-Jordan. Seedlings were planted during the seasons of 1999 and 2000 and furrow irrigated with different mixtures of potable water to treated wastewater {100%:0% (1:0, control); 25%:75% (1:3); 50%:50% (1:1); 0%:100% (0:1)}. Tomato fruit, soil and water were examine for heavy metals concentrations, and changes in the pH and electrical conductivity (EC) of the soil were tested. The obtained results revealed an increase in the concentrations of Cu, Mn and Fe, in the soil correlated with high concentrations found in the wastewater. Additionally, an increase in the pH and EC in the soil was observed with increasing the proportions of wastewater. Results of tomato fruit analysis showed an increased concentration of Fe, Cu, Ni, Mn and Zn in the cultivar “RS₅₈₉₉₅₆”, whereas, an increased concentration of Mn and Zn were detected in the cultivar “GS₁₂”, but no accumulation of Cd and Pb in both cultivars. The accumulation of heavy metals in fruit was below the Jordanian standard limits, thus, the use of treated wastewater in irrigation might be feasible.     

Acclimation to partial shading or full sunlight determines the performance of container-grown Fraxinus ornus to subsequent drought stress

Cultivation techniques in the nursery aimed to improve tolerance to abiotic stresses after planting in the landscape may have great ecological value. Here we tested the hypothesis that the irradiance at which plants grow in the nursery may impact on their responses to a subsequent drought stress. Measurements of relevant morpho-anatomical, physiological and biochemical traits were conducted in Fraxinus ornus, a member of the Oleaceae family of increasing interest as an urban tree. Leaves developed under moderate shade displayed a lower ability to preserve water balance, thus suffering from a greater decline in net CO₂ assimilation than leaves acclimated to full sunlight, when subsequently exposed to drought stress. Shaded leaves also displayed an inherently lower capacity to dissipate excess radiant energy through nonphotochemical quenching, thus suffering from greater oxidative damage than sun leaves under drought. These results indicate that sunlight irradiance at which container-grown ash trees grow in the nursery may tightly affect the tolerance to subsequent drought stress. This may have great value for enhancing the establishment of container-grown plants in the landscape, as fully leaved plants may suffer from severe drought stress during early stages of acclimation in the landscape.     

哈尔滨交通干道两侧土壤重金属潜在生态危害评价

以哈尔滨市公滨路、香成路、哈-腰堡路3条交通干道两侧的土壤为主要研究对象,用原子吸收光谱法分析土壤中重金属Cu、Cd、Pb、Zn、Cr、Ni含量,采用松嫩平原土壤重金属背景值作为参比值,应用地质累积指数法和潜在生态危害评价法对重金属污染进行评价,以研究公路交通引起的土壤中重金属污染以及潜在的生态危害。结果表明:研究区土壤中Cu、Cd、Pb、Zn、Cr、Ni的含量显著高于背景值。Cd和Pb为中等污染,土壤对重金属元素的污染程度:ZnPbCdCrNiCu。污染源主要为机动车燃料、轮胎、机械中所含微量重金属成分。     

城市污泥施用对喀斯特石漠化土壤质量的改善

为研究城市污泥施用对喀斯特地区石漠化土壤质量的改良效果,以石漠化土壤和城市污泥为试验材料,采用模拟土壤熟化试验,分析了20%~75%比例的污泥添加对土壤持水性能、养分、重金属含量及微生物生物量的影响。结果表明:随着污泥用量的增加,土壤饱和含水率增加了22.04%~67.07%,持水时间延长了5.19~16.25 d;土壤有机碳、氮、磷含量及微生物生物量也显著增加。但土壤微生物生物量不是随污泥施用比例的增加而增加,在污泥施用比例为20%~35%范围内,土壤微生物生物量显著高于高比例的污泥添加。50%~75%的污泥施用还导致Cd和Zn超过土壤质量标准。因此,适量的城市污泥施用可改善土壤持水性能、提高土壤肥力,以20%~35%比例为宜。     

Effects of cadmium and copper on pollen germination and fruit set in pea (Pisum sativum L.)

In this work, pea (Pisum sativum) plants exposed to increasing cadmium and copper concentrations were tested for heavy metals accumulation in flowers and for ‘in vivo’ pollen germination. Based on the Cd and Cu accumulation amounts in the flowers, an evaluation of the same metals effects on ‘in vitro’ pollen germination was achieved. Moreover, the effects of both metals on fruits number and weight and on seed set and yield at individual plant level were examined. While cadmium concentrations did not affect ‘in vivo’ pollen germination, only higher copper concentrations rendered a significant reduction. This is in contrast with the clear negative effect on pollen germination in vitro and might be explained by the different dynamic and bioavailability of both metals. A clear effect of Cd and Cu was observed on two important yield components ie, fruit weight and seed set. Although results obtained herein cannot give a clear cut relationship between the effect of Ca and Cu on reproductive development and its consequences on yields, they represent emerging results on the potential consequences of metals contamination on reproductive development in plants.     

Cultivation of beans (Phaseolus vulgaris L.) in limed or unlimed wastewater sludge,vermicompost or inorganic amended soil

Wastewater sludge can be vermicomposted to increase its nutrient content and reduce pathogens. The effect of vermicompost wastewater sludge on soil characteristics and growth of bean plants (Phaseolus vulgaris L.) was compared with that of inorganic fertilizer, untreated sludge or sludge treated with lime to pH 12. Plants cultivated in vermicompost amended soil developed best while those amended with inorganic fertilizer least. Bean plants grown in the unlimed amended soil had the highest total N content of 3.97 g kg⁻¹, but only 6 active and 8 total nodules. Plants cultivated in unamended soil and added with inorganic fertilizer had >20 active and total nodules, but ≤2.12 g N kg⁻¹ dry plant. It was found that limed and unlimed sludge stimulated development of bean plants to a larger extent than those cultivated in inorganic fertilized soil or unamended soil in the greenhouse, but less than those cultivated in vermicompost amended soil.     

Mixtures of crushed rock, forest soils, and sewage sludge used as soils for grassed green areas

In two container experiments, we evaluated mixtures of crushed rock, forest soil, and sewage sludge for use as growth media in green areas. We applied two types of crushed rock (0–2 mm fraction), two forest soils (sandy loam), and limed sewage sludge (pH 10), and studied the growth of ryegrass (Lolium multiflorum var. westervoldicum) during one growing season.Including ≥0.2 m³ m⁻³ sewage sludge in the soil mixtures initially inhibited growth, presumably due to toxic levels of ammonium-N. Up to 0.25 m³ m⁻³ sludge increased the total yield of ryegrass, but at a level as low as 0.1 m³ m⁻³, more nutrients were available than could be taken up by the crop. At present, up to 0.3 m³ m⁻³ sewage sludge is allowed in soil mixtures used in green areas in Norway, although that level should probably be lowered due to the risk of abnormal (enhanced or inhibited) plant growth, and leaching of nutrients. We recommend a maximum of 0.1 m³ m⁻³ when applying the kind of sludge used in our experiments.All mixtures containing acid forest soil gave better results than those comprising slightly alkaline forest soil. The best mixture for ryegrass was crushed rock and acid forest soil at a ratio of 1:2. Compared to pure acid forest soil ryegrass grew equally well or better on mixtures containing ≥0.50 m³ m⁻³ acid forest soil. The differences in growth between the various soil mixtures were due to texture and physical properties, and to dissimilarities in the effects of sewage sludge on mineralisation of nitrogen in the mixtures comprising acid and slightly alkaline forest soil.     

忻州市灌区土壤重金属污染评价及分布特征分析

以忻府区某典型污灌区农田土壤为研究对象,对重金属污染进行了风险评价且对土壤剖面的重金属含量和形态进行了分析,以期为污灌区重金属污染土壤的修复、环境治理及科学灌溉等提供参考依据。结果表明:长期污水灌溉已导致农田土壤表层土壤中的Cu、Zn、Ni、Cr、Pb、Cd、Hg、As含量相对背景值不同程度的累积,分别是土壤背景值的1.21、0.71、1.23、1.73、1.38、4.62、3.59、1.00倍,只有Zn的平均含量低于土壤的背景值。以国家土壤环境质量标准二级限量值作为污染评价阈值,在25个采样点中,2个采样点的土壤综合污染指数高于0.7,属警戒水平,其它均属于安全水平。8种重金属元素中,表层土壤中的Cu、Zn、Cd、As含量最高,Cr、Hg在80~100 cm含量最高,Ni、Pb在不同土壤中无明显差异。Cr、Zn主要以残渣态形式存在,Cu、Ni、Cd、As主要以残渣态和有机结合态存在,Pb主要以铁锰氧化物结合态和有机结合态存在,Hg以残渣态和可交换态为主,Hg的迁移风险大。     

Estimation of relative water use among ornamental landscape species

Low water use plantings may enhance water conservation in dry landscapes. However, appropriate plant selection is hindered by the dearth of information available on the water needs of different species. A direct method of classification was tested under the hypothesis that relative water use by woody landscape species growing in 3.8 l containers would be representative of the water use of the same species in the landscape. Four species of distinctly different ecological origin (Leucophyllum frutescens, Spiraea vanhouteii, Viburnum tinus, Arctostaphylos densiflora) were chosen in order to obtain a wide range of responses, and their water use was measured in plants growing in 3.8 l containers and compared to that of the same species growing in drainage lysimeters, representative of landscape conditions. Half of the plants were subjected to successive cycles of stress by withholding water after irrigation to container capacity in containers, or applying a fraction of the potential evapotranspiration in lysimeters. The good fit of the regression of average daily water use by lysimeter plants on average daily water use by container plants (R²=0.87,P<0.01) reflects the consistency of relative water use of the four species. Measurement of water use at the end of nursery production may be useful for predicting the relative water use of various species after establishment in the landscape.     

北京道路绿地十种花灌木对四种重金属的富集能力评价

采集北京四环路道路两侧绿地中10种花灌木一二年生枝条、叶片和其根系土壤,利用电感耦合等离子体发射光谱仪(ICP-AES)测定其中Cd、Pb、Zn、Cu的含量,评价分析园林常用绿化灌木对土壤重金属的富集能力,以期为园林植物修复重金属污染土壤提供参考依据。结果表明:同一花灌木中重金属含量基本表现为Zn>Cu>Pb>Cd;Cd、Cu富集含量在同一花灌木器官中表现为叶>枝,而Pb、Zn富集含量多数植物表现为枝>叶;花灌木对不同重金属元素的富集系数存在着一定的差异,对Zn的平均富集系数较高,为0.50;对Cd、Pb、Cu的平均富集系数较低且相近,小于0.25。通过差异性分析,木槿、月季、紫丁香、珍珠梅分别对Cd、Pb、Zn、Cu的单一富集系数显著高于其它花灌木(P<0.05);从综合富集系数来看,紫丁香对Cd、Pb、Zn、Cu的综合富集能力最强。该研究结果为北京道路绿地及其它场地污染治理、景观建设的植物树种选择提供科学依据和参考。     

丛枝菌根真菌促进植物抗重金属镉的研究进展

丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)是土壤中一类广泛存在的植物共生真菌,已有研究表明,AMF能够提高植物对重金属的抗逆性和耐受性。该研究从AMF与植物2个方面介绍了相关研究领域的前沿动态,旨在推进AMF促进植物耐受Cd机制的深入研究。在根外,丛枝菌根真菌能够直接吸收、固持Cd,以及改变植物根际的土壤微环境,从而影响Cd的形态和生物活性,增强植物对Cd胁迫的抗性。在根内,丛枝菌根真菌调节植物通过体内螯合、转运以及启动抗氧化防御系统等特定的生理生化过程,减少高浓度Cd对植物的胁迫和伤害。此外,丛枝菌根真菌还能通过促进植物生长来抵御Cd胁迫。     

Heavy metals and their neutralization related to ornamentals

Selectively working cation exchangers (® Lewatit OC 1029, OC 1030 and OC 1034, Bayer AG, Leverkusen) are very effective for the immobilization of ions of heavy metals (Zn²⁺, Cu²⁺, Pb²⁺). Applied at the calculated doses in a soil and/or substrate contaminated with ions of heavy metals, these cation exchangers withdraw the contaminants from the existing equilibrium system, which results in a neutralization of the fraction of the undesired phytotoxic identities. This method not only offers many possibilities in common peat and leaf mould soils, but gives a guarantee for plant-production in contaminated autochthonous areas and heterochthonous substrates. Ornamental plants and nursery trees developed well, especially in a terminated emission atmosphere, even in very strongly contaminated soils.