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Following the basic incubation study, a greenhouse experiment was conducted to elucidate the efficiency of vetiver grass (Vetiveria zizanioides L.), with or without chelating agents, in remediating lead (Pb)‐contaminated soils from actual residential sites where Pb‐based paints were used. Because the primary factor affecting Pb phytoavailability in soils is soil pH, we used two soil types widely varying in pH that have total Pb concentrations above 1500 mg kg?1 soil. Lead‐contaminated, low pH, acidic soils were collected from residential sites in Baltimore, MD and high pH, alkaline soils were collected from residential sites in San Antonio, TX. Based on the soil characterization results, two most appropriate soils (one from each city, having similar Pb levels but variable soil physico‐chemical properties) were selected for this study. Ethylenediaminetetraacetic acid (EDTA) and [S,S′]ethylenediaminedisuccinate (EDDS) were applied at 5, 10, and 15 mmol kg?1 soil. Lead uptake and translocation in vetiver was determined on day 10 after chelants addition. Plant and soil analysis show that EDTA treated soils have maximum Pb uptake and lower total soil Pb levels. Prediction models developed for exchangeable Pb show a strong correlation for total Pb accumulated in vetiver grass. Results of the sequential chemical extraction of the soils at both initial and final time‐points, indicates a significant mobilization of Pb by the two chelants from carbonate‐bound fraction to exchangeable pool. Information on physico‐chemical properties of contaminated residential soils help in predicting Pb phytoextraction and thus further help in calibrating a successful chelant‐assisted phytoremediation model. 相似文献
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Genetic transformation is gaining importance for developing plant types suitable to metal accumulate and/or hyperaccumulate. In this study, the transgenic tobacco plant which transferred the ScMTII gene from Saccharomyces cerevisiae to wild type tobacco cultivar Petite Havana (SR1) was grown on soils with low and high cadmium (Cd) and zinc (Zn) concentrations in a growth chamber for 6 weeks and compared to wild type tobacco for Cd and Zn accumulation. Cadmium and Zn accumulations in the transgenic and wild type tobacco plants were increased with the increasing Cd and Zn concentrations. Unlike Zn, the transgenic plant accumulated significantly higher amount of Cd compared to the wild type control plants. Shoot Cd concentrations of transgenic tobacco in higher Cd dosages reached the above the hyperaccumulation threshold value of 100 mg Cd kg?1 in the dry weight (DW). Transgenic tobacco accumulated 354, 400, 372, and 457 mg Cd kg?1 DW, for 10, 20, 40, and 80 mg Cd kg?1 soil treatments, respectively. These values are 3.5–4.5‐fold higher than that of Cd hyperaccumulation threshold value. With 10 mg kg?1 Cd treatment, the bioconcentration factor (BCF) of transgenic tobacco plants for Cd reached up to 35 in which the threshold value for BCF should be at least 10. Our results showed that the transgenic tobacco may be used as a good Cd hyperaccumulator plant and for phytoextraction of Cd contaminated soils, but not for Zn. 相似文献
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《Chemie der Erde / Geochemistry》2014,74(3):385-391
Sunflower (Helianthus annuus) is cultivated as food and feed crop as well as for bioenergy production. It is also investigated towards its ability to remove contaminants from soil and accumulate them in the shoots (phytoextraction). So the reliable prediction of element contents in shoots based on soil contents would be advantageous to easily decide whether plants grown on a certain area could be either used as food and feed or for phytoremediation in combination with bioenergy production. However, it is desirable to predict element contents in plants based on only a few numbers of predictors. This would mean on the one hand a reduced effort in time and costs for analysis and on the other hand existing data on soil quality could be than used for estimations of the element uptake of plants on larger scales. Samples of sunflowers were used, that were grown in plots situated at two different sites in Germany and treated with different amendments (NPK-fertilizer, Streptomyces + Mycorrhiza, Rendzina). One site (heavy metal polluted) was the test field “Gessenwiese”, which is situated on the area of the former uranium leaching heap “Gessenhalde”. The other site (non-contaminated) was the lysimeter station Falkenberg. Shoot contents of Ca, Cd, Co, Cu, K, Ni, Pb, and Zn were correctly predicted by the mobile soil fraction extracted with 1 M NH4NO3 solution (simple regression), whereas for Mg, S, and U the specifically adsorbed soil fraction (extraction with 1 M NH4OAc solution) needs to be added as predictor (PLS regression). Mn was the only element in the data set for which simple regression based on total soil contents (digestion with HF, HClO4, and HNO3) had to be used be used for correct prediction in the studied data set. 相似文献
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Comparison on the phytoextraction efficiency of Bidens pilosa at heavy metal contaminated site in natural and electrokinetic conditions 
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下载免费PDF全文 Li Yue-nan Gu Yan-sheng Li Man-zhou Huo Guang-jie Wang Xi-ping Xu Zhi-jie Yue Jie Du Dan Geng Man-ge 《地下水科学与工程》2021,9(2):121-128
The plant samples of Bidens pilosa were collected from a coal gangue vacant site and its surrounding area, located in central China, to study the remediation effect of the plant species on heavy metal(HM) contamination in both natural and electrokinetic(EK) conditions. The analytical results showed that the effect of phytoextraction and bioconcentration on the heavy metals in the sample of the EK group is more significant than those in the other control group. Compared with the results of natural condition, under the EK condition the concentrations of cadmium(Cd), lead(Pb), copper(Cu) and zinc(Zn) in the stems and leaves of the Bidens pilosa increased to 0.40 mg/kg, 4.23 mg/kg, 7.27 mg/kg, 830.24 mg/kg, respectively,with their increments of 292%, 1 731%, 141%, 2 076%. For root samples, the Cd, Pb, Cu and Zn concentrations increased to 0.52 mg/kg, 4.36 mg/kg, 10.87 mg/kg, and 98.12 mg/kg and the increase rates were 1 034%, 140%, 29%, and 181%, respectively. The phytoextraction efficiency of the Bidens pilosa was significantly higher than that of control group. The removal efficiency of Cd, Pb, Cu and Zn in soil increased to 26%, 72%, 27%, and 79% with the EK applied. In addition, the mechanism of HM migration,extraction and enrichment in Bidens pilosa under the EK condition was discussed. 相似文献
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