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1.
Lead inactivation in soils by zeolites 总被引:6,自引:0,他引:6
Barbara Gworek 《Plant and Soil》1992,143(1):71-74
Three-year pot experiments, carried out in a greenhouse, and laboratory investigations proved that the introduction of synthetic zeolites into lead-contaminated soils led to a reduction in the lead content of plants and thus contributed to a reduction in lead in the nutrient cycle. Lettuce leaves grown on a lead-contaminated soil amended with zeolites were 49–73% lower in Pb content than those on soils with no zeolites added.For grasses, these reductions were 47–77%, for the aboveground parts of oats 58–68%, for beet leaves 62%, and for beet roots 26–83%. 相似文献
2.
The mobility of heavy metals in contaminated soils is dependent on the kinetics release from soils. Metal extraction over time is commonly used to distinguish two or more fractions of metal based on differences of extraction or release rates. Kinetic studies using 0.01 M CaCl2, 0.01 M malic acid, and 0.01 M EDTA extractions were performed to characterize nickel (Ni) and lead (Pb) kinetic release in 10 contaminated calcareous soils. Proportions of Ni and Pb extracted with EDTA were higher than when using malic acid and CaCl2, respectively. The release of Ni and Pb was characterized by an initial fast rate followed by a slower rate and could best be described by a two first-order reactions model with rate constants k1 and k2 and two metal pools: readily labile (Q 1) and less labile (Q 2). In an EDTA extractant, different Q1 /Q2 ratios for Ni and Pb were observed, indicating binding energies to soil constituents is not comparable. The k1 of the model for Ni (average of 10 soils: 0.2204 h?1 and 0.2359 h?1 for 0.01 M CaCl2 and 0.01 EDTA, respectively) was higher than Pb (0.1044 h?1 and 0.1631 h?1 for 0.01 M CaCl2 and 0.01 M EDTA, respectively), indicating a higher potential of Ni for leaching and groundwater contamination in contaminated calcareous soils. Relationships between the fraction of Ni and Pb determined with the two first-order reactions model and the soil composition and Pb fractions were established. The results indicated that the efficiency of the extractions Ni and Pb from soils depends both on the Ni and Pb content and soil composition. Overall, the results indicated that the use of a 0.01 M malic acid washing solution would be preferred in the field condition. 相似文献
3.
The natural relationship13C/12C determined in three soil profiles under grass vegetation indicated a depletion in organic13C at depth: theδ
13C was between −18‰ and −15‰ in the A horizons and ranged from −18 to −22‰ at depth. Previous work showed that in forest soils,
whereδ
13C was near −28‰ in the upper horizon, there was, on the contrary, a relative enrichment of the lower strata. This meant thatδ
13C, initially different in the various topsoils, became more equal at depth. Comparison between dark, deep horizons (sombric
horizons), which are certainly of illuvial origine, would confirm this:δ
13C of grassland and a forest sombric horizon were almost equal at around −22‰. These results might mean that, in natural ecosystems,
the isotopic carbon composition of the soil underlying humus would be independent of the vegetation type. This would have
practical implications for the use of13C as a tracer for soil organic matter studies. 相似文献
4.
The hyperaccumulator Thlaspi caerulescens J & C Presl. was grown in seven different soils collected from around Europe that had been contaminated with heavy metals by industrial activity or the disposal of sewage sludge to land. Zinc accumulation factors (shoot concentration/initial soil solution concentration) ranged from 3500–85 000 with a mean value of around 36 000. This compares with mean accumulation factors of 636, 66 and 122 for Cd, Ca and Mg, respectively. The concentration of Zn in the shoots was much greater than in the roots. The total removal of Zn and Cd ranged from 8 to 30 and from 0.02 to 0.5 mg kg-1 soil, respectively. The Zn concentration in shoots of T. caerulescens correlated, using a curvilinear relationship, with the initial Zn concentration in soil solution (R2 = total Zn 0.78; Zn2+ 0.80). There was no relationship between the uptake of Zn and the total Zn concentration in the soil. In most soils, solution pH increased only slightly after growth of T. caerulescens, indicating that acidification was not the mechanism used to mobilise Zn in the soil. Dissolved organic carbon concentrations generally increased but characterisation of the component organic compounds was not attempted. The concentrations of Zn and Cd in soil solution decreased considerably after growth of T. caerulescens. The percentages of Zn and Cd in soil solution present as free ions also decreased. However, the decrease of Zn in soil solution after growth accounted for only about 1% of the total Zn uptake by T. caerulescens. This was much lower than for Cd, Ca and Mg. The results suggest that either T. caerulescens was highly efficient at mobilising Zn which was not soluble initially, or the soils used had large buffering capacities to replenish soil solution Zn within a short time. This work highlights the need to investigate the role of root exudates on the mobilisation of Zn and Cd in soils by the hyperaccumulator T. caerulescens. 相似文献
5.
《Chemical Speciation and Bioavailability》2013,25(3):163-169
AbstractTo better understand the environmental impact of lead (Pb) in shooting range soils, Pb levels in three berm soils were characterized via size distribution, total Pb concentration, water-soluble Pb, sequential extraction and X-ray diffraction (XRD). About 60% of the mid-berm soils of ranges-G and -O existed in grain sizes between 0.5 and 0.25mm (medium sand) while range-L was most abundant in the 0.25–0.106mm (fine sand) size fraction. All three range soils had the most accumulation of lead (60–70%) in the very coarse sand size (2.0–1.0 mm). In ranges-G and -L, the index shows a decreasing Pb enrichment with decreasing particle size, which may be a result of bullet fragmentation and abrasion in shooting range soils. Sequential extractions reveal that ranges-G and -L had the highest proportion of Pb bound to organic matter while range-O was dominated by the carbonate-bound fraction. However, a substantial proportion (one-third) of Pb in soil from the three shooting ranges was associated with carbonates. The XRD result revealed the dominance of carbonates in range-O soil, calcite in range-G soil and metallic lead in ranges-G and -O soil. The conversion of metallic lead to carbonates may be a mechanism for natural attenuation of lead in shooting range soils. Implications for remediation of shooting range soils are further discussed. 相似文献
6.
Jae-Kyu Yang Mark O. Barnett Philip M. Jardine Scott C. Brooks 《Soil & Sediment Contamination》2003,12(2):165-179
The relative oral bioaccessibility of labile Pb(II) and As(V) added to soils was investigated in a well-characterized soil using a physiologically based extraction test (PBET) to simulate metal solubility in a child's digestive system. The effect of soil and PBET (i.e., simulated stomach and small intestine) pH, soil metal concentration, soil to solution ratio, and soil-metal aging time were investigated. Arsenic bioaccessibility was relatively unaffected by a variation in simulated stomach and small intestine pH over the range 2 to 7 and soil pH over the range 4.5 to 9.4. In contrast, Pb(II) bioaccessibility was strongly dependent on both the simulated stomach, small intestine, and soil pH, showing enhanced sequestration and decreased bioaccessibility at higher pH values in all cases. Although the bioaccessibility of Pb(II) was constant over the concentration range of approximately 10 to 10,000?mg/kg, the As(V) bioaccessibility significantly increased over this concentration range. The bioaccessibility of both arsenic and lead increased as the soil-to-solution ratio decreased from 1:40 to 1:100. Additional lead sequestration was not observed during 6 months of soil aging, but As(V) bioaccessibility decreased significantly during this period. 相似文献
7.
《Chemical Speciation and Bioavailability》2013,25(4):247-255
AbstractColumn leaching using [S, S]-ethylene diamine disuccinate ([S, S]-EDDS) on copper tailing soils was carried out to investigate metal content and fractionation after leaching. The soil column was divided into four layers after leaching. Fractionation of Cu, Pb, Zn, and Mn in soil was analyzed using a modified BCR sequential extraction method. Metal contents (Cu, Pb, Ca, Mn) in soil layers increased with the depth of the soil column after leaching in the [S, S]-EDDS treatment. The cumulative extraction efficiency was approximately 43.1% for Cu, 26.8% for Zn, 19.5% for Pb, 10.5% for Ca, 2.07% for Mg, 58.5% for Mn, and 7.92% for Fe. The removal of the reducible fractions of Cu and Mn and the exchangeable fraction of Zn was the most significant in the treatment with [S, S]-EDDS. The exchangeable fraction of Pb was the main fraction that was affected by leaching using [S, S]-EDDS. Distribution of Cu and Mn were severely modified by leaching with [S, S]-EDDS. Percentages of residual fractions of the tested heavy metals in the treatment with [S, S]-EDDS after leaching were much higher than that in the control. Although column leaching using [S, S]-EDDS could remove target metals effectively and impaired their availability, it also dissolved large amounts of major elements and modified the distribution of Mn appreciably. 相似文献
8.
9.
The uptake of lead by two contrasting plant species, radish and red fescue, grown in soils contaminated by mine spoil was investigated. Uptake was found to be poorly correlated either with pH or total Pb concentration in the soils. By contrast, a good correlation was obtained, particularly for red fescue, between Pb uptake and Pb concentration in the solution of equilibrated soil suspensions over a wide range of soil pH, total soil Pb and soil solution Pb concentration.Calculations suggested a similar order of magnitude in the total amounts of Pb taken up by the plants and Pb in the soil solution of the root zone, justifying the latter as a good index of Pb-availability. ei]Section editor: A C Borstlap 相似文献
10.
重金属污染土壤植物修复基本原理及强化措施探讨 总被引:88,自引:11,他引:88
阐述了植物修复的基本概念及主要作用方式 ,并从土壤中重金属存在形态 ,植物对重金属吸收、排泄和积累以及植物生物学特性与植物修复的关系等方面讨论了重金属污染土壤植物修复的基本原理及局限性和限制性因素 ,从超富集植物性能强化和技术强化两方面探讨了植物修复的强化措施 ,并指出与现代化农业技术相结合是植物修复重金属污染土壤大规模商业应用的一条捷径 相似文献
11.
12.
Variation in the uptake of Arsenic, Cadmium, Lead, and Zinc by different species of willows Salix spp. grown in contaminated soils 总被引:1,自引:0,他引:1
Pavel Tlustoš Jir̆ina Száková Markéta Vysloužilová Daniela Pavlíková Jan Weger Hana Javorská 《Central European Journal of Biology》2007,2(2):254-275
The experiment assessed the variability of in seven clones of willow plants of high biomass production (Salix smithiana S-218, Salix smithiana S-150, Salix viminalis S-519, Salix alba S-464, Salix ’Pyramidalis’ S-141, Salix dasyclados S-406, Salix rubens S-391). They were planted in a pots for three vegetation periods in three soils differing in the total content of risk elements.
Comparing the calculated relative decrease of total metal contents in soils, the phytoextraction potential of willows was
obtained for cadmium (Cd) and zinc (Zn), moderately contaminated Cambisol and uncontaminated Chernozem, where aboveground
biomass removed about 30% Cd and 5% Zn of the total element content, respectively. The clones showed variability in removing
Cd and Zn, depending on soil type and contamination level: S. smithiana (S-150) and S. rubens (S-391) demonstrated the highest phytoextraction effect for Cd and Zn. For lead (Pb) and arsenic (As), the ability to accumulate
the aboveground biomass of willows was found to be negligible in both soils. The results confirmed that willow plants show
promising results for several elements, mainly for mobile ones like cadmium and zinc in moderate levels of contamination.
The differences in accumulation among the clones seemed to be affected more by the properties of clones, not by the soil element
concentrations or soil properties. However, confirmation and verification of the results in field conditions as well as more
detailed investigation of the mechanisms of cadmium uptake in rhizosphere of willow plants will be determined by further research. 相似文献
13.
新疆野生多伞阿魏生境土壤理化性质和土壤微生物 总被引:2,自引:0,他引:2
对新疆准尔盆地南缘的野生多伞阿魏(Ferula ferulaeoides(Steud.)Korov)生境的土壤理化性质和土壤微生物进行了研究。结果表明:阿魏土壤的pH值范围在8.50—10.38之间;含水率1.94%—4.33%;速效氮(碱解氮)含量在7.18到38.01mg/kg之间,随土层深度的增加而迅速递减;速效磷的含量在1.65到7.79 mg/kg之间,随土层深度的增加而迅速递减;速效钾含量在140.72到363.78 mg/kg之间;有机质含量在5.47到13.89 g/kg之间。在各样地每克土中土壤微生物的平均数量分别为:细菌为1.75×105,放线菌为1.04×105,真菌为2.65×103。细菌主要生活在0—10 cm的表层,10 cm以下数量变化不大;而放线菌和真菌则主要分布在中间两层,即10—20 cm和20—30 cm。 相似文献
14.
《Chemical Speciation and Bioavailability》2013,25(1):71-78
AbstractSelected heavy metals Fe, Cd, Ni and Cr were studied in contaminated soil samples collected from south-eastern Nigeria. Geochemical differentiation into different chemical fractions, using Ma and Rao six-step sequential chemical extraction procedure, was carried out to assess the potential mobility and bioavailability of the heavy metals in the soil profiles. The residual fraction was the most important phase for the four heavy metals with the following average percentage values 74.43 for Fe, 37.69 for Cd, 70.11 for Ni and 62.47 for Cr. The carbonate fraction contained an appreciable proportion of Fe, Cd and Ni with the average percentage values of 16.29, 14.86 and 10.47 respectively, while organic fraction was of next importance for Cr with an average percentage value of 27.14. The Fe-Mn oxide fraction also contained 15.86% of Cd. Relatively low amounts of the metals were associated with water soluble and exchangeable fractions. The mobility factors for the metals in all the sites ranged from 8.55 to 40.04 for Fe, 8.66 to 56.58 for Cd, 12.74 to 30.19 for Ni and 0.82 to 7.22 for Cr. The generally low values of mobility factors coupled with significantly high levels of association of the metals with the residual fraction, indicate that the metals do not pose any environmental risk nor hazard. 相似文献
15.
Due to rapid industrialization and urbanization, human activities like industrial and agricultural production, transportation, aggravate heavy metal pollution in soil and continue to endanger vegetables and human health. In this study, three contaminated areas affected by heavy metal pollution in Guangdong Province were investigated in terms of Cu, Zn, Pb, and Cd concentrations in soil and vegetables. Further analyses of the contamination status and potential risks to the health of residents consuming these vegetables were conducted. Results showed the following average heavy metal concentrations in vegetables and soil: Shaoguan > Guangzhou > Dongguan, indicating that mining has caused massive soil-heavy metal pollution. The heavy metal concentrations and Bioconcentration factors (BCFs) showed the following trend: leaf-vegetables > fruit-vegetables > root-vegetables, and those of vegetable type were as follows: Cd > Zn > Cu > Pb. The Nemero pollution index (PI) of all research region soils and hazard index (HI) exceeded 1. Hence, more attention should be paid to the potential for adverse health effects caused by the consumption of vegetables produced in these sites . Thus, effective measures are encouraged, with a focus on children due to their vulnerability to these heavy metals. 相似文献
16.
In vitro bioaccessibility testing is gaining popularity as a tool to estimate the oral bioavailability of contaminants in soil for human health risk assessment (HHRA). Bioaccessibility tests are used to measure the bioaccessible fraction of a contaminant in soil, which can then be used to estimate the bioavailable fraction. Inherent uncertainties are associated with bioaccessibility tests. Various test parameters need to be carefully considered in their development, including the liquid to soil (L/S) ratio employed. We used L/S ratios (v:wt) ranging from 25 ml:1 g to 1,000 ml:1 g in a modified relative bioaccessibility extraction procedure to investigate the effects on bioaccessibility of lead and arsenic in field and reference soils. General trends of increased percent bioaccessibility of lead and arsenic with increasing L/S ratio were observed in the reference soil. A similar positive relationship was observed for lead in the field soil; soluble arsenic concentrations were below the detection limit and data were insufficient to observe a trend. Percent bioaccessibility was significantly affected at each extreme of the L/S ratios tested (p < .05). Biological relevance, technical feasibility, and mathematical relationships with in vivo results should be considered when selecting an appropriate L/S ratio for bioaccessibility testing. 相似文献
17.
衡阳紫色土丘陵坡地植被恢复阶段土壤特性的演变 总被引:15,自引:0,他引:15
采用空间代替时间序列方法,对衡阳紫色土丘陵坡地不同恢复阶段的土壤理化性质、土壤微生物数量、土壤微生物学性质和主要酶活性特征以及它们之间的相互关系进行研究。结果表明:不同恢复阶段土壤理化特征存在明显差异,从狗尾草群落阶段(Ⅰ)、紫薇-狗尾草群落阶段(Ⅱ)、牡荆+剌槐群落阶段(Ⅲ)到枫香+苦楝-牡荆群落阶段(Ⅳ),0—40cm土壤含水量、容重、非毛管孔隙度、孔隙比、大于0.25mm水稳性团聚体含量、有机碳(SOC)、全氮(TN)、碱解氮(AN)与速效磷(AP)显著增加,土壤容重显著减小,土壤pH值逐渐减小,土壤全磷(TP)、全钾(TK)与速效钾(AK)其差异变化不大,土壤理化特征的差异引起土壤微生物数量、微生物学性质与土壤酶活性的变化;不同恢复阶段土壤微生物总数显著增加,其中细菌数量显著增加,而真菌与放线菌数量显著减少;不同恢复阶段土壤基础呼吸(SBR)、土壤微生物量碳(SMBC)、土壤微生物量氮(SMBN)、土壤微生物量磷(SMBP)、土壤微生物熵(Cmic/Corg)显著增加,而代谢熵或呼吸熵(qCO2)显著减小,碳氮比(C/N)逐渐减小;不同恢复阶段均显著地增加了脲酶(URE)、蔗糖酶(INV)与磷酸酶(APE)的活性;土壤理化性状、土壤微生物数量、土壤微生物学性质与土壤酶活性之间存在密切的相关性。 相似文献
18.
Sudarshan Kumar Dutta Dhanwinder Singh Aditya Sood 《Soil & Sediment Contamination》2011,20(3):249-260
Lead (Pb) is a non-biodegradable contaminant, present in the environment, especially near lead-based industrial sites, agricultural lands, and roadside soils. Bioavailability of Pb in the soil is controlled by the sorption and desorption behavior of Pb, which are further controlled by the soil chemical and physical properties. In this study, sorption and desorption amounts of Pb in soil were compared with soil physical (sand, silt, clay content) and chemical (pH; electrical conductivity, EC; percent organic carbon, (%OC); cation exchange capacity, CEC) properties. Twenty-six surface soils (0–5cm), expected to vary in physical and chemical properties, were collected from different parts of India and were treated with known concentration of Pb solution (40 μg/L). The amount of Pb sorbed and desorbed were measured and correlated with soil properties using simple linear regressions. Sorption was significantly (p ≤ 0.05) and positively correlated with pH, and %OC; desorption was significantly (p ≤ 0.05) negatively correlated with the same two factors. Stepwise multiple regressions were performed for better correlations. Predicted sorption and desorption amounts, based on multiple regression equations, showed reasonably good fit (R2 = 0.79 and 0.83, respectively) with observed values. This regression model can be used for estimation of sorption and desorption amounts at contaminated sites. 相似文献
19.
Sulphur fractionation and availability to plants are poorly understood in calcareous soils. Sixty-four calcareous soils containing varying amounts of CaCO3 were collected from ten provinces in China and their S fractions determined. Organic S was the predominant fraction of S, accounting for on average 77% of the soil total S. The amounts of adsorbed sulphate were found to be negligible. 1 M HCl extracted substantially more sulphate than either 0.01 M CaCl2 or 0.016 M KH2PO4, indicating the existence of water-insoluble but acid-soluble sulphate, probably in the form of sulphate co-precipitated with CaCO3. The concentrations of water-insoluble sulphate correlated positively with the contents of CaCO3 and accounted for 0.03–40.3% (mean 11.7%) of soil total S. To test the bioavailability of water-insoluble sulphate, a sulphate-CaCO3 co-precipitate labelled with 35S was prepared and added to a calcareous soil in a pot experiment with either NH4+ or NO3– as the N source. In 29 days, wheat plants took up 10.6% and 3.0% of the 35S added to the soil in the NH4+ and NO3– treatments, respectively. At the end of the pot experiment, the decrease of water-insoluble, acid-soluble, sulphate was more apparent in the NH4+ than in the NO3– treatment. The results indicate that sulphate co-precipitated with CaCO3 in calcareous soils may become partly available for plant uptake, depending on rhizosphere pH, if the field precipitate is similar to the laboratory prepared sample studied. 相似文献
20.
从秦岭凤县铅锌污染区4种植物根际共鉴定出球囊霉属(Glomus)丛枝菌根真菌(Arbuscular mycorrhizal ungi,AMF)12种,其中缩球囊霉(G.constrictum)是该区域的优势种;缩球囊霉、副冠球囊霉(G.coronatum)、苏格兰球囊霉(G.caledonium)和聚丛球囊霉(G.aggregatum)对铅锌污染具有较强的耐性,而地球囊霉(G.geospo-rum)、台湾球囊霉(G.formosanum)、地表球囊霉(G.versiforme)和两型球囊霉(G.dimorphicum)对铅锌污染的耐性较弱.相关分析表明,土壤Pb、Zn、速效P浓度和pH较低时,对AMF丰度有一定的促进作用,当Pb、Zn、速效P浓度和pH较高时,对AMF丰度为抑制作用,AMF丰度与高浓度Pb呈极显著负相关,与高浓度速效P呈显著负相关.通径分析表明,Pb是影响秦岭重金属污染区AMF丰度的主要因素,其直接和间接作用都较大,而pH、速效P和Zn主要通过Pb的间接作用来影响AMF丰度. 相似文献