Relationship between heavy metal concentrations of herbaceous plants and soils at four Pb-Zn mining sites in Yunnan, China

This paper studied the relationship between heavy metal concentrations of herbaceous plants and soils at four Pb-Zn mining sites in Yunnan, China. 50 herbaceous plant samples of 9 plant species from 4 families and 50 soil samples were collected and then ana1yzed for the tota1 concentrations of Pb, Cd, and Zn. The results showed that the average concentrations of Pb, Cd, and Zn in soil samples were 3772.83, 168.81, and 5385.65 mg/kg, respectively. The average concentrations of Pb, Cd, and Zn were 395.68, 28.14, and 1664.20 mg/kg in the shoots, and 924.12, 57.25, and 1778.75 mg/kg in the roots, respectively. Heterospecific plants at the same site and conspecific plants at various sites had different average levels of Pb, Cd, and Zn, both in the shoots and the roots. Enrichment coefficients of Pb, Cd, and Zn were greater than 1 in 2, 3, and 9 herbaceous plant samples, respectively. Translocation factors of Pb, Cd, and Zn were greater than 1 in 10, 17, and 25 herbaceous plant samples, respectively. In all 50 samples, the concentrations of Pb, Cd, and Zn between the shoots and the roots, the shoots, and the soils, and the roots and the soils had significant positive relationships.     

宝山堇菜多金属吸收特征和耐性策略

宝山堇菜Viola baoshanensis Shu,Liu et Lan是一种Cd超富集植物,但它对不同重金属的吸收和转运能力有待进一步研究。从湖南桂阳宝山多金属矿区中筛选4个宝山堇菜优势分布的小生境,分析这些生境中宝山堇菜及其根区土壤的重金属质量分数。化学分析结果显示,宝山堇菜优势分布土壤中Cd、Pb、Zn、Cu、Mn和Fe的平均质量分数（mg/kg）分别为471、15 044、8 273、1 776、4 702和69 054。宝山堇菜地上部Cd、Pb、Zn、Cu、Mn和Fe的平均质量分数（mg/kg）分别为387、1 077、1 037、99、379和1 812,其中Cd、Pb超过超富集植物标准,Zn、Cu的平均质量分数大约是Zn、Cu超富集植物标准的10%,Mn的平均质量分数低于Mn超富集植物标准的5%,Fe的平均质量分数高于1 000 mg/kg。上述结果表明,宝山堇菜可以超富集Cd和Pb,富集Zn、Cu和Fe以及低积累Mn。此外,宝山堇菜对不同重金属差别化吸收模式可能也代表了超富集植物适应重金属复合污染土壤的一种策略。     

EDTA and citric acid mediated phytoextraction of Zn, Cu, Pb and Cd through marigold (Tagetes erecta)

Phytoextraction is an emerging cost-effective solution for remediation of contaminated soils which involves the removal of toxins, especially heavy metals and metalloids, by the roots of the plants with subsequent transport to aerial plant organs. The aim of the present investigation is to study the effects of EDTA and citric acid on accumulation potential of marigold (Tagetes erecta) to Zn, Cu, Pb, and Cd and also to evaluate the impacts of these chelators (EDTA and citric acid) in combination with all the four heavy metals on the growth of marigold. The plants were grown in pots and treated with Zn (7.3 mg l(-1)), Cu (7.5 mg I(-1)), Pb (3.7 mg l(-1)) and Cd (0.2 mg l(-1)) alone and in combination with different doses of EDTA i.e., 10, 20 and 30 mg l(-1). All the three doses of EDTA i.e., 10, 20 and 30 mg l(-1) significantly increased the accumulation of Zn, Cu, Pb and Cd by roots, stems and leaves as compared to control treatments. The 30 mg l(-1) concentration of citric acid showed reduced accumulation of these metals by root, stem and leaves as compared to lower doses i.e., 10 and 20 mg l(-1). Among the four heavy metals, Zn accumulated in the great amount (526.34 mg kg(-1) DW) followed by Cu (443.14 mg kg(-1) DW), Pb (393.16 mg kg(-1) DW) and Cd (333.62 mg kg(-1) DW) in leaves with 30 mg l(-1) EDTA treatment. The highest concentration of EDTA and citric acid (30 mg l(-1)) caused significant reduction in growth of marigold in terms of plant height, fresh weight of plant, total chlorophyll, carbohydrate content and protein content. Thus EDTA and citric acid efficiently increased the phytoextractability of marigold which can be used to remediate the soil contaminated with these metals.     

Effects of cadmium on nutrient uptake and translocation by Indian Mustard

Plants that hyperaccumulate metals are ideal subjects for studying the mechanisms of metal and mineral nutrient uptake in the plant kingdom. Indian Mustard (Brassica juncea) has been shown to accumulate moderate levels of Cd, Pb, Cr, Ni, Zn, and Cu. In this experiment, 10 levels of Cd concentration treatments were imposed by adding 10-190 mg Cd kg(-1) to the soils as cadmium nitrate [Cd(NO3)2]. The effect of Cd on phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and the micronutrients iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in B. juncea was studied. Plant growth was affected negatively by Cd, root biomass decreased significantly at 170 mg Cd kg(-1) dry weight soils treatment. Cadmium accumulation both in shoots and roots increased with increasing soil Cd treatments. The highest concentration of Cd was up to 300 mg kg(-1) d.w. in the roots and 160 mg kg(-1) d.w. in the shoots. The nutrients mainly affected by Cd were P, K, Ca, Fe, and Zn in the roots, and P, K, Ca, and Cu in the shoots. K and P concentrations in roots increased significantly when Cd was added at 170 mg kg(-1), and this was almost the same level at which root growth was inhibited. Zn concentrations in roots decreased significantly when added Cd concentration was increased from 50 to 110 mg kg(-1), then remained constant with Cd treatments from 110 to 190 mg kg(-1). However, Zn concentrations in the shoots seemed less affected by Cd. It is possible that Zn uptake was affected by the Cd but not the translocation of Zn within the plant. Ca and Mg accumulation in roots and shoots showed similar trends. This result indicates that Ca and Mg uptake is a non-specific process.     

三明铅锌矿区植物对重金属的富集特征

采用野外调查与室内分析相结合的方法,对福建三明典型矿区尤溪铅锌矿、大田铅锌矿以及尤溪铅锌矿冶炼厂等进行了调查,研究这些矿区重金属含量较高的区域如采矿区、尾砂库、洗矿排水沟以及铅锌矿冶炼厂厂区和排水沟冲积扇区域土壤中的Pb、Zn和Cd的含量,在此基础上,对在这些区域自然定居的16种优势植物体内的三种重金属元素的耐性、富集特性进行了分析。结果表明:该矿区的主要优势物种为禾本科和菊科植物,其中笔管草(Equisetum ramosissimum)、一年蓬(Erigeron annuus)和五节芒(Miscanthus floridulus)的地上部重金属富集量较大,对矿区周边污染土壤修复有潜在应用价值;乌蕨(Stenoloma chusana)、千金子(Bochloe dactyloides)、二歧飘拂草(Fimbristylis dichotoma)、柔枝莠竹(Microctegium Vimineum)、短叶水蜈蚣(Kyllinga brevifolia)、狗娃花(Heteropappus hispidus)适用于污染程度较高且植物萃取技术难以实施的重金属污染矿业废弃地。矿区植物地上部Zn含量平均值最高,为1225.74mg·kg-1,植物地上部Pb含量范围在52.78～2137.11mg·kg-1,平均为521.39mg·kg-1;一年蓬地上部Cd含量达到了119.51mg·kg-1,超过了超富集植物的临界值100mg·kg-1,转运系数为1.3,是潜在的Cd超富集植物。     

矿冶区周边水稻对不同来源重金属污染的指示作用

有色金属开采与冶炼可对周边环境造成严重的重金属污染,查明重金属污染来源对于矿冶周边重金属污染管理与控制具有重要意义.为探索利用矿冶周边水稻对As、Cd、Pb、Zn和Cu的富集与水稻体内元素的含量平衡特征指示重金属污染来源的可行性,选择了我国著名的水口山Pb-Zn矿山开采与冶炼周边区,根据重金属污染排放和迁移扩散特征,结合当地气象和地貌条件,确定了3个典型采样区,其中两个采样区分别邻近冶炼厂和尾砂库,另一处为位于两者之间的过渡区.采用蛇形采样法在稻田内采集33个成熟水稻及土壤样品,分析水稻不同部位(包括根、茎叶、籽粒)及土壤中As、Cd、Pb、Zn、Cu5种重金属和其他16种元素的含量.结果表明,3个采样区之间土壤中的As、Cd、Pb、Zn和Cu含量均存在显著性差异;各采样区水稻中除根际和籽粒中Cd含量外,各部位重金属含量也均有显著差异.靠近冶炼厂的水稻茎叶中As、Pb含量高于离冶炼厂较远的采样区水稻茎叶.尽管As、Pb在靠近尾砂库采样区土壤中含量最高,但在该区水稻茎叶中的含量却最低;在除As、Cd、Pb、Zn、Cu5种重金属以外的其他16种元素中,水稻根部仅有5种元素含量在各采样区之间存在差异,指示相同的土地利用类型及土壤母质条件;而在茎叶和籽粒中则分别有多达11和10种元素含量出现采样区差异,指示重金属污染来源影响水稻茎叶及籽粒中元素的含量平衡.多元统计分析结果显示,3个采样区水稻茎叶中元素含量平衡存在显著的分异,显示出明显的采样区属性.结合采样区域空间位置、污染物来源、水稻对重金属的富集与转运特征分析,3个采样区重金属主要污染特征可分别确定为水-气混合来源型、大气来源型和尾砂来源型.论文结果证明利用水稻茎叶指示矿冶周边重金属污染来源是可行的.     

铅锌冶炼厂土壤污染及重金属富集植物的研究

对株洲市铅锌冶炼厂生产区进行了植被和土壤调查。结果表明，该厂土壤污染以镉铅锌(Cd、Pb、Zn)最为严重，尤其是重金属镉在土壤中含量超过背景值高达208倍，分析原因主要是由于大气尘降和雨水淋洗等使得污染加重。实验采集并分析测定了9种植物中重金属富集量，首次报道了土荆芥是一种铅超富集植物，其体内Pb质量分数高达3888mg／kg。另一种植物商陆能大量富集镉，具有地下部向地上部转运能力强、生物量大、富集总量高的特点，有很大研究价值和应用潜力。另外，荨麻对Zn有较强富集能力，这3种植物可分别用于铅、镉和锌等3种重金属污染土壤的植物修复。     

4种鸢尾属植物对铅锌矿区土壤中重金属的富集特征和修复潜力

通过野外调查和实地修复铅锌矿污染土壤试验,研究了铅锌矿区排污渠污水及底泥中Pb、Zn、Cu、Cd含量和分布特征以及4种鸢尾属植物马蔺（Iris lactea var.chinensis）、黄菖蒲（Iris pseudacorus L.）、溪荪（Iris sanguinea Donn ex Horn.）、花菖蒲（Iris ensata Thunb.）对Pb、Zn、Cu、Cd的积累能力和土壤修复效率差异。结果表明,离污染源越近,重金属污染越严重。Pb、Zn、Cu、Cd4种重金属均大部分沉积在排污水渠的底泥中,污水中Pb严重污染,超标达120倍,底泥中Pb、Zn、Cu、Cd质量分数分别超标1.5倍、1.7倍、1.6倍和1.7倍。排污渠岸土壤Pb、Zn、Cu、Cd质量分数也明显超过了国家规定的土壤环境质量Ⅱ级标准1～5倍。种植4种鸢尾属植物后,土壤中Pb、Zn、Cu、Cd质量分数有所降低。其中,种植马蔺1个月后土壤Pb、Cu、Cd修复效率分别为8.13%、2.45%和22.3%。黄菖蒲和花菖蒲对Zn的修复效率相对较高。4种鸢尾属植物中马蔺对Pb、Cd的吸收能力最强,马蔺地上部（叶、茎）Pb质量分数达983mg·kg-1,且转运系数大于1,是一种潜在的Pb积累植物,黄菖蒲、溪荪和花菖蒲对Zn的吸收能力较强,且吸收的重金属主要积累在根系。     

Forage and rangeland plants from uranium mine soils: long-term hazard to herbivores and livestock?

Metalliferous uranium mine overburden soils integrated into arable land or stabilized by perennial rangeland plants evoke concern about the quality of crops and the exposure of grazing and thereby soil-ingesting (wildlife) herbivores to heavy metals (HM) and radionuclides. In a 2-year trial, thirteen annual and perennial forage and rangeland plants were thus potted on, or taken from, cultivated field soil of a metalliferous hot spot near Ronneburg (Germany). The content of soil and shoot tissues in 20 minerals was determined by ICP-MS to estimate HM (and uranium) toxicities to grazing animals and the plants themselves, and to calculate the long-term persistence of the metal toxicants (soil clean-up times) from the annual uptake rates of the plants. On Ronneburg soil elevated in As, Cd, Cu, Mn, Pb, U, and Zn, the shoot mineral content of all test plants remained preferentially in the range of “normal plant concentrations” but reached up to the fourfold to sixfold in Mn, Ni, and Zn, the 1.45- to 21.5-fold of the forage legislative limit in Cd, and the 10- to 180-fold of common herb concentrations in U. Shoot and the calculated root concentrations in Cd, Cu, Ni, and Zn accounted for phytotoxic effects at least to grasses and cereals. Based on WHO PTWI values for the tolerable weekly human Cd and Pb intake, the expanded Cd and Pb limits for forage, and reported rates of hay, roots, and adhering-soil ingestion, the tolerable daily intake rates of 0.65/11.6 mg in Cd/Pb by a 65 kg herbivore would be surpassed by the 11- to 27/0.7- to 4.7-fold across the year, with drastic consequences for winter-grazing and thereby high rates of roots and soil-ingesting animals. The daily intake of 5.3–31.5 mg of the alpha radiation emitter, U, may be less disastrous to short-lived herbivores. The annual phytoextraction rates of critical HM by the tested excluder crops indicate that hundreds to thousands of years are necessary to halve the HM and (long-lived) radionuclide load of Ronneburg soil, provided the herbage is harvested at all. It is concluded that the content in Cd/As, Cd, and Cu exclude herbage/Ronneburg soil from the commercial use as forage or pasture land soil for incalculable time spans. Caution is required, too, with the consumption of game.     

The uptake and translocation of selected elements by cole (Brassica) grown using oasis soils in pot experiments

Pot experiments were conducted on cole (Brassica) grown in soils jointly treated with traces of two heavy metals cadmium (Cd) and zinc (Zn). As the concentration of heavy metals in the soil increased, the uptake of these metals by the plants rose. However, the ratio of heavy metal concentration in soil to uptake by plants increased at a slower rate. Bioavailability of heavy metals considered between the roots and soil using non-linear regressions was shown to be statistically significant. Similarly, the bioavailability of these two heavy metals between leaves and roots using a linear regression was also statistically significant. The bioconcentration factors (BCFs) for Cd and Zn were 0.282 and 4.289, respectively. Significant variation of BCF with the heavy metal bioavailability in soil was noted from non-linear models. The transfer factors (TFs) were 4.49 for Cd and 1.39 for Zn. The Zn concentration in leaves under all treatments did not exceed threshold set standards, but Cd levels exceeded these standards when the concentration of Cd in the soil was more than 1.92 mg kg^?1 dry weight (dw). Data indicate that cole (Brassica) is not a suitable crop for oasis soils because of plant contamination with heavy metals, especially Cd.     

Heavy metal pollution in soil and plants at bone char site

This study determined the heavy metal concentration in soil and plants at a bone char site in Umuahia, Nigeria. Soil and plant samples collected in a randomized complete block design (RCBD) were analyzed for zinc (Zn), lead (Pb), cadmium (Cd), nickel (Ni), and arsenic (As). The concentration of metals in soil and plants in the vicinity of the bone char site are as follows: Zn (172?mg?kg^?1) and Ni (0.62?mg?kg^?1) in soil were highest at site P₃, Pb (2.37?mg?kg^?1) and As (0.08?mg?kg^?1) at site P₁, and Cd (18.30?mg?kg^?1) at site P₂. In plants, the concentrations of Zn (41.17?mg?kg^?1) and Cd (3?mg?kg^?1) were highest in Albizia ferruginea, Ni in Dialium guineense (0.09?mg?kg^?1), while Pb was in D. guineense (0.08?mg?kg^?1) and Spathodea companulata (0.06?mg?kg^?1). The levels of Zn, Cd, Pb, Ni, and As in soil ranged from 11.2 to 172, 2.68 to 18.2, 0.026 to 2.37, 0.33 to 0.62, and 0.02 to 0.08?mg?kg^?1, respectively. In plants, the concentration of Zn, Cd, Pb, and Ni ranged from 2.01 to 41.17, 0.12 to 3, 0.02 to 0.08, and 0.03 to 0.09?mg?kg^?1, respectively. There were significant correlations between Zn and Cd, and Pb and As in soil. The high concentration of Cd in soil might affect soil productivity.     

多种盐分离子作用下苋菜对重金属的吸收累积特征

模拟不同淋洗脱盐阶段滩涂土壤孔隙水中盐分和重金属含量,通过苋菜水培试验,研究多种盐分离子（SO42-、Cl-、NO3-、CO32-、Na＋、Ca2＋、K＋和Mg2＋等）的共同作用下,苋菜对Zn、Cu、Ni、Cr、Pb和Cd 6种重金属的吸收、累积和转运的变化。结果表明,与对照相比,在不同盐分离子浓度影响下,苋菜茎叶中Cd的累积增幅为69.2%～146.2%,而茎叶中其他重金属的含量无显著变化,苋菜根系中Cd、Pb、Cr、Ni和Cu含量的最大增幅分别为187.8%、197.7%、305.7%、228.1%和58.2%,但根系中Zn含量未受到显著影响。在相对较高的盐分离子浓度（〉1 312.4 mg.L-1）范围内,不同盐分离子浓度处理间苋菜茎叶和根系中6种重金属含量差异均不显著。盐分处理显著降低了苋菜对Pb、Cr、Ni和Cu的转移系数,但未显著影响苋菜对Cd和Zn的转移系数。     

铅锌矿区周边耕地土壤团聚体重金属污染状况及风险评估

为了解铅锌矿区耕地土壤团聚体污染状况,以贵州省都匀范家河铅锌矿区周围耕地土壤为研究对象,研究土壤团聚体中镉(Cd)、铅(Pb)、锌(Zn)3种重金属垂直分布特征和赋存形态。采用三步连续提取法(BCR)对污染土壤团聚体中3种重金属进行赋存形态分析,利用分布因子法(DFx)和地质累积指数法(Igeo)评估其环境风险。结果表明:土壤样品中重金属Cd、Pb和Zn的平均质量分数分别为23.25、518.40、3471.83 mg·kg^-1,已分别达到贵州土壤背景值的35.23、36.35、14.73倍,且3种重金属在土壤团聚体中的含量与其主要赋存形态特征均存在明显差异。研究区域剖面土壤中各粒径Cd主要以残渣态和可还原提取态的形式存在,各粒径Pb主要以残渣态和可氧化提取态的形式存在,80%及以上各粒径Zn为残渣态,综合得出研究区域土壤中重金属潜在影响程度为Cd>Pb>Zn。分布因子法结果表明:在0-100 cm剖面深度,Cd主要富集在0.25-1 mm的颗粒中,Pb主要富集在1-2 mm的颗粒中,Zn主要富集在0.053-2 mm的颗粒中;地质积累指数法结果显示,各粒径颗粒中Cd、Zn的污染水平主要为重污染,Pb主要为偏重污染。研究矿区周围耕地土壤已受到严重的重金属污染,应采取有效措施进行修复治理。该文为范家河铅锌矿区环境风险评价提供基础,旨在为矿区环境管理提供数据支撑。     

三明铅锌矿区植物对重金属的富集特征

采用野外调查与室内分析相结合的方法,对福建三明典型矿区尤溪铅锌矿、大田铅锌矿以及尤溪铅锌矿冶炼厂等进行了调查,研究这些矿区重金属含量较高的区域如采矿区、尾砂库、洗矿排水沟以及铅锌矿冶炼厂厂区和排水沟冲积扇区域土壤中的Pb、Zn和Cd的含量,在此基础上,对在这些区域自然定居的16种优势植物体内的三种重金属元素的耐性、富集特性进行了分析。结果表明：该矿区的主要优势物种为禾本科和菊科植物,其中笔管草（Equisetum ramosissimum）、一年蓬（Erigeron annuus）和五节芒（Miscanthus floridulus）的地上部重金属富集量较大,对矿区周边污染土壤修复有潜在应用价值;乌蕨（Stenolomachusana）、千金子（Bochloe dactyloides）、二歧飘拂草（Fimbristylis dichotoma）、柔枝莠竹（Microctegium Vimineum）、短叶水蜈蚣（Kyllingabrevifolta）、狗娃花（Heteropappushispidus）适用于污染程度较高且植物萃取技术难以实施的重金属污染矿业废弃地。矿区植物地上部zn含量平均值最高,为1225．74mg·kg-1,植物地上部Pb含量范围在52．78-2137．11mg·kg-1,平均为521．39mg·kg-1;一年蓬地上部cd含量达到了119．51mg·kg-1,超过了超富集植物的临界值100mg·kg-1,转运系数为1．3,是潜在的Cd超富集植物。     

Assessment of As and Heavy Metal Contamination in the Vicinity of Duckum Au-Ag Mine, Korea

In order to assess the potential of As and heavy metal contamination derived from past mining activity and to estimate the human bioavailability quotients for As and heavy metals. Tailings, soils and crop samples were collected and analysed for As, Cd, Cu, Pb and Zn. The mean concentrations of As, Cd, Cu, Pb and Zn in the tailings were 68.5, 7.8, 99, 3,754 and 733 µg g^–1, respectively. Maximum Pb concentration in tailings was up to 90 times higher than its tolerable level. The concentrations of these metals were highest in the soils from the dressing plant area, and decreased in the order: farmland soil to paddy soil. In particular, some of the soils from the dressing plant area contained more than 1% of Pb and Zn. The pollution index ranged from 0.19 to 1.93 in paddy soils, and from 1.47 to 3.60 in farmland soils. The average concentrations of heavy metals in crops collected from farmland were higher than those in rice stalks or rice grains, and higher than the internationally accepted limits for vegetables. Element concentrations extracted from farmland soils within the simulated human stomach for 1 h are 9.4 mg kg^–1 As, 3.8 mg kg^–1 Cd, 37 mg kg^–1 Cu, 250 mg kg^–1 Pb and 301 mg kg^–1 Zn. In particular, the extracted concentrations of Cd, Pb and Zn are in excess of the tolerable levels. The results of the simple bioavailability extraction test (SBET) indicate that regular ingestion (by inhalation and from dirty hands) of soils by the local population could pose a potential health threat due to long-term toxic element exposure.     

4种草对铅锌尾矿污染土壤重金属的抗性与吸收特性

盆栽试验的结果表明,高羊毛、早熟禾、黑麦草、紫花苜蓿在纯尾矿污染土壤或经处理的尾矿污染土壤上都能生长,但在处理的土壤上生长的植物长势明显优于对照,其中紫花苜蓿的生物量所受影响比其他几种草坪草更大,说明其重金属抗性低于其他几种植物。单位面积上 4 种植物体内重金属质量分数高低均为 w(Zn)>w(Pb)>w(Cu)>w(Cd),但每种植物对 Cd、Pb、Zn 和 Cu 的吸收质量分数和分布均不相同,一般为根系质量分数大于茎叶。加入改良剂(CaCO3)和有机肥(菜枯)使生长在铅锌尾矿污染土壤上的 4 种草坪草生物量显著增加,植物体中的 Cd、Pb、Zn 质量分数下降,但 Cu 质量分数反而上升,结果单位面积上草坪草吸收各重金属元素的量均有所增加,可见利用改良措施与草坪草相结合的方法来修复重金属污染土壤具有可行性。     

Accumulation of heavy metals in soil and paddy crop (Oryza sativa), irrigated with water of Ramgarh Lake,Gorakhpur, UP,India

Heavy metals, a highly polluting group of constituents known to exert adverse effects, tend to accumulate in living organisms. The objective of this study was to determine the accumulation and translocation of heavy metals in soil and in paddy crop irrigated with lake water compared to soil and paddy crop irrigated with bore-well water. The quantities of heavy metals (Cd, Cr, Cu, Pb, Zn, As, Mn, and Hg) were determined in different parts of rice plants (Oryza sativa). Results revealed that the mean levels of soil Cd, Cr, Pb, Zn, As, Mn, and Hg in experimental soil and in different parts of rice plant (root, straw, and grain) were higher than the control except for Cu. The content of eight toxic metals was significantly higher in root than in aerial parts of the rice (straw and grains). Rice roots were enriched in Cd, As, Hg, and Pb from the soil, while Cr, Cu, Zn, and Mn were hardly taken by the roots. Bioaccumulation factor for Hg was significantly higher than other heavy metals. Metal transfer factors from soil to rice plants were significant for Cd, Cr, Cu, Pb, Zn, As, Mn, and Hg. The concentrations of metals in lake water were found to be within the permissible limit of Indian standard prescribed by Central Pollution Control Board (2000), except for Hg and As, which were higher than the limit of Indian standard. However, the concentrations of heavy metals in soil and rice grains were still below the maximal levels, as stipulated by Indian Prevention of Food Adulteration Act (PFA, 1954) and World Health Organization (WHO, 1993) guidelines.     

Influence of lead on growth and nutrient accumulation in canola (Brassica napus L.) cultivars

Canola (Brassica napus L.) is commonly used as a hyper-accumulator for phytoextraction of heavy metals from soil and water. Like many other heavy metals, lead (Pb) contaminates soil, water and air and thus it is a great problem. This study was conducted to investigate toxic effects of Pb on growth and nutrient uptake in four canola cultivars. Each of four cultivars of canola (Con-II, Con-III, Legend and Shiralee) was subjected to four levels of Pb (0, 30, 60 and 90 mg Pb kg(-1) of soil) from lead chloride [PbCl2]. Due to Pb toxicity, plant growth was adversely affected and relatively a severe reduction in root biomass (45.7%) was recorded. The Pb accumulation increased both in shoot and root, the highest being in root. The uptake of different nutrients, i.e., N, P, K, Ca, Mg, Zn, Cu and Mn was reduced (38.4, 32.8, 33.1, 49.6, 7.78, 52.0, 42.6 and 45.9%, respectively) in the shoots and that of N, Fe, Zn, and Cu in the roots (48.5, 33.2, 24.3 and 44.8%, respectively) of all canola cultivars. The root K, P, Zn and Mn and shoot P, Mg and Fe contents were less affected, the concentration of Pb, Ca and Mg in roots of all cultivars. Among canola cultivars Con-II and Con-III performed better than Legend and Shiralee in terms of growth (26.03%) and nutrient accumulation. Overall, plant growth and nutrient accumulation in the canola cultivars was hampered due to the presence of Pb.     

Uptake and accumulation of potentially toxic elements in colonized plant species around the world’s largest antimony mine area,China

To provide information on reclamation of multi-heavy metal polluted soils with conception of phytostabilization, a field survey on the uptake and accumulation of potentially toxic elements such as antimony (Sb), arsenic (As), lead (Pb), cadmium (Cd), copper (Cu), and zinc (Zn) in colonized plant species around the world’s largest antimony mine area, China, was conducted. Samples including leaves and shoots (including roots and stems) of colonized plants as well as rhizospheric soils were collected from eight sampling zones in the studied area. The results showed that the contents of Cu, Zn, and Pb in rhizospheric soils below plants were comparable to the corresponding background values of Hunan province, otherwise Sb, Cd, and As contents were extremely high (17–106, 17–87, and 3–7 times of the corresponding background values). The highest concentration of Sb was found in Aster subulatus (410 mg kg^?1); Cd, As, and Zn were in Herba bidentis bipinnatae (10.9, 264, and 265 mg kg^?1, respectively); and Cu was in Artemisia lavandulaefolia (27.1 mg kg^?1). It also exhibited that all the contents of As in leaves were several times of those in shoots of plants, Cd and other heavy metals showed in a similar pattern in several studied species, implying that the uptake route of these heavy metals via foliar might contribute to the accumulation. With high bioconcentration factors of heavy metals (more than 1, except for Zn), together with the growth abundance, Herba bidentis bipinnatae was considered as the most suitable colonized species for phytostabilization of the multi-heavy metal pollution in soils on this antimony mine area.     

Bioavailability and health risk assessment of potentially toxic elements in Thriasio Plain,near Athens,Greece

Elevated concentrations of potentially toxic elements (PTEs) are usually found in areas of intense industrial activity. Thriasio Plain is a plain near Athens, Greece, where most of the heavy industry of the country has been situated for decades, but it also is a residential and horticultural area. We aimed at measuring the levels of PTEs in soils and indigenous plant species and assessing the health risk associated with direct soil ingestion. Samples of soils at roadsides and growing plants were collected from 31 sites of that area. Concentrations of Al, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, V and Zn were measured in both soils (as pseudo-total) and aerial plant tissues. We found that As, Cd, Cr, Cu, Ni, Pb and Zn were higher than maximum regulatory limits. Element concentrations in plants were rather lower than expected, probably because indigenous plants have developed excluder behaviour over time. Copper and Zn soil-to-plant coefficients were highest among the other elements; for Cu this was unexpected, and probably associated with recent Cu-releasing industrial activity. Risk assessment analysis indicated that As was the element contributing more than 50 % of the health risk related to direct soil ingestion, followed by Cr, Pb, and, surprisingly, Mn. We concluded that in a multi-element contamination situation, elevated risk of PTEs (such as As, Cr and Pb) may reduce the tolerance limits of exposure to less-toxic elements (here, Mn).