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Simultaneous extraction of soil phytoavailable cadmium,copper, and lead by chelating resin membrane 总被引:2,自引:0,他引:2
Cadmium, copper, and lead were extracted from suspensions of contaminated soils using metal chelating exchange resin membranes.
Nine soils with widely varying properties and Cd, Cu and Pb levels were tested. Soil suspensions made up with 4 g in 40 mL
deionized water were equilibrated with 5 cm2 Ca-saturated Chelex exchange resin membrane which was retained inside a polypropylene bag and shaken at 150 rpm for 24 hrs.
Resin membrane extractable Cd, Cu and Pb of the soils were correlated with Cd, Cu, and Pb uptake by young wheat seedlings
grown in these soils and compared with soil Cd, Cu, and Pb extracted by 0.1 M HCl, 0.01 M CaCl2, and 0.005 M Diethylenetriamine pentaacetic acid (DTPA). The amounts of Cd, Cu and Pb extracted by the Ca-saturated Chelex membrane from
all tested soils correlated well with those absorbed by young wheat seedlings. The Ca-saturated Chelex membrane extractable
Cd, Cu and Pb of the soil had the strongest correlation with plant uptake Cd, Cu and Pb among the extraction methods we tested.
It was demonstrated that the Ca-saturated Chelex membrane extraction is an appropriate method in simultaneously estimating
Cd, Cu and Pb phytoavailability of soil and is applicable to a wide range of soils. 相似文献
2.
Chromium present in the forms of Cr(VI) or Cr(III) in soils. Since the toxicity and mobility of Cr(VI) are higher than those
of Cr(III), it would be important to estimate soil Cr(VI) accurately in order to assess the phytotoxicity of Cr. Soil redox
potential can influence the distribution of Cr between Cr(VI) and Cr(III) forms, and thus an in situ method which is not affected by the soil redox condition is needed for determining Cr(VI) availability in paddy fields. In
this study, the Cu-saturated selective ion exchange resin (DOWEX M4159), serving as an infinite sink, was embedded in soils
to extract available Cr(VI) from three representative saturated soils with different amounts of Cr(VI). The results suggested
that Cr(VI) reduction occurred in the flooded soils, and the acid environment favored the adsorption and reduction of Cr(VI).
There was a significant dose-response relationship between the soil resin-extractable Cr(VI) and the plant height of rice
seedlings for test soils. The experimental results suggested that the embedded selective ion exchange resin method could be
a suitable in situ method for assessing the phytotoxicity of Cr in flooded soils. 相似文献
3.
Comparison of As sequestration in iron plaque and uptake by different genotypes of rice plants grown in As-contaminated paddy soils 总被引:1,自引:0,他引:1
Chien-Hui Syu Chia-Hsing Lee Pei-Yu Jiang Mei-Kuei Chen Dar-Yuan Lee 《Plant and Soil》2014,374(1-2):411-422
Background and aims
Limited information is available on comparing the iron plaque formation capabilities and their effect on arsenic (As) uptake by different rice plant genotypes grown in As-contaminated soils. This study investigates the effect of iron plaque on As uptake in different rice genotypes grown in As-contaminated soils from the Guandu Plain of northern Taiwan.Methods
Twenty-eight rice genotypes including 14 japonica and 14 indica genotypes were used in this study. Rice seedlings were grown in As-contaminated soils for 38 days. The iron plaque formed on the rice roots were extracted using dithionite–citrate–bicarbonate. The concentrations of As, Fe, and P in soil solutions, iron plaque, and plants were measured. The speciation of As in the root’s iron plaque was determined by As K-edge X-ray absorption near-edge structure spectroscopy (XANES).Results
The amounts of iron plaque formation on roots were significantly different among 28 tested rice genotypes, and 75.7–92.8 % of As uptake from soils could be sequestered in iron plaque. However, there were no significant negative correlations between the amounts of Fe or As in the iron plaque and the content of As accumulated in rice plants of tested genotypes. XANES data showed that arsenate was the predominant As species in iron plaque, and there were difference in the distribution of As species among different rice genotypes.Conclusions
The iron plaque can sequester most of As uptake from soils no matter what rice genotypes used in this study. However, the iron plaque alone did not control the extent of As accumulation in rice plants from As-contaminated soils among 28 tested rice genotypes. Low As uptake genotypes of rice selected from this study can be recommended to be grown in the As-contaminated soils. 相似文献4.
Iron plaque formation and its effect on arsenic uptake by different genotypes of paddy rice 总被引:2,自引:0,他引:2
Background and aims
Iron plaque on roots has been hypothesized to be an effective restraint on the uptake of arsenic (As) by rice plants. Evaluating the formation of iron plaque and its effect on As uptake by various rice cultivars is valuable because selecting low As uptake rice cultivars results in reduced risks associated with rice consumption. This study examines iron plaque formation and its effect on As uptake by different genotypes of rice cultivars.Methods
Hydroponic cultures were conducted in phytotron at day 25/night 20°C and the rice seedlings in fifth-leaf age were treated with Fe (II) at the levels of 0 and 100 mg L?1 in the Kimura B nutrient solutions for 14 days. The amount of iron plaque formation of 28 rice cultivars was determined by using the DCB extractable Fe of roots. Four cultivars representing high and low iron plaque formation capability, from indica and japonica respectively, were selected out of the 28 cultivars and processed for Fe and As treatments. After Fe treatments for 4 days, the seedlings were fed with As (III) at levels of 0, 0.5, and 1 mg L?1 for another 10 days. We were thus able to determine the amounts of iron plaque formation and the As content in iron plaque, roots, and shoots of the four tested cultivars.Results
Iron plaque formation capability differed among tested twenty-eight rice cultivars. Feeding As to four tested cultivars enhanced iron plaque formation on roots; the As uptake by roots and shoots was decreased by the addition of Fe. Both the retention of As on iron plaque and the decrease of As uptake by the addition of Fe varied among tested cultivars and were not correlated with the iron plaque formation capability.Conclusions
Iron plaque can sequestrate As on the roots and reduce rice’s As uptake. However, other factors also influence the As uptake, namely the differences in binding affinity of iron plaque to As, the existent As species in the rhizosphere, and the uptake capability of various As species by rice plants. These factors should also be considered when selecting low As uptake rice cultivars. 相似文献5.
Dar-Yuan Lee Yu-Na Shih Hsiu-Ching Zheng Chiou-Pin Chen Kai-Wei Juang Jyh-Fu Lee Lo Tsui 《Plant and Soil》2006,281(1-2):87-96
The Cu-saturated selective ion exchange resin (DOWEX M4195) extraction method was used to investigate the effects of two amendments,
5 and 15% organic matter in the form of hog-dung compost (HC) or cattle-dung compost (CC), on Cr(VI) bioavailability in three
soils spiked with various levels of Cr(VI). The results showed that addition of composts could decrease the amounts of resin-extractable
Cr(VI) in Cr(VI)-spiked soils, and the CC amendment decreased resin-extractable Cr(VI) more than the HC amendment. The X-ray
Absorption Near-edge Structure spectroscopy (XANES) method was used to examine the distribution of Cr(III) and Cr(VI) species
in Cr(VI)-spiked soils that were affected by compost amendments, and to elucidate the mechanisms for the decrease of resin-extractable
Cr(VI) due to the application of composts. The XANES results suggested that the decrease in the amounts of resin-extractable
Cr(VI) after compost addition was mainly due to the reduction of Cr(VI) to Cr(III). The amounts of soil resin-extractable
Cr(VI) were also correlated with wheat seedling growth in order to evaluate the effect of compost amendments on decreasing
the phytotoxicity of soil Cr(VI). The results showed that there was a sigmoidal relationship between soil resin-extractable
Cr(VI) and the plant height of wheat seedlings and the obtained effective concentrations of resin-extractable Cr(VI) resulting
in 10 and 50% growth inhibition (EC10 and EC50) were 76 and 191 mg kg−1 respectively. The above results suggested that the resin extraction method was a useful tool for assessing Cr(VI) phytotoxicity
and that addition of composts would enhance Cr(VI) reduction to Cr(III) in soils and thus relieve Cr(VI) phytotoxicity. 相似文献
6.
Chromium in soils is present in the form of Cr(VI) oxyanions or Cr(III) cations. The toxicity and mobility of Cr(VI) are higher than those of Cr(III), thus it is essential that the availability of Cr(VI) in soils be accurately estimated in order to assess the phytotoxicity of Cr and its resultant health hazards to animals and humans. In this study, the Cu-saturated selective ion exchange resin (DOWEX M4195) was used as an infinite sink to test the feasibility of using the resin for extracting available Cr(VI) from soil. In the experiments, the results show that the resin had a high affinity for Cr(VI) and that Cr(VI) adsorbed by resins could be desorbed by using 10% NaCl (pH 4). In addition, the adsorption and desorption of Cr(VI) were not affected by pH levels, the forms of Cr(VI) or the presence of major anions in the soil solution. The above results indicate that the Cu-saturated resin can selectively adsorb Cr(VI) from solution. In the soil extraction experiments, three Cr(VI)-spiked soils were processed using the Cu-saturated resin extraction method. The results show that amounts of soil Cr extractable by the resin had a significant negative correlation to the height of wheat seedlings grown in the Neubauer test. Comparing this to the commonly used extractant, 0.1 M HCl, the amount of soil Cr, extractable by the resin, had a higher correlation to plant height. The results suggest that the selective ion exchange resin method developed in this study is useful in evaluating the quantities of plant-available Cr(VI) in soil and can, therefore, assess the phytotoxicity of Cr in soil. 相似文献
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