不同淋洗剂对不同性质污染土壤中镉的浸提效率比较

以三种外源添加Cd的低污染土壤(酸性、石灰性和高有机质土壤)为研究对象,对比了两种螯合剂,两种酸性溶液对Cd的浸提效果。结果表明,螯合剂的浸提效率高于酸性溶液,并呈现出EDTAEDDS柠檬酸和HCl的顺序。三种土壤上,在0.05~0.20 mol L-1的浓度范围内,EDTA和EDDS随浓度的升高对Cd的浸提效率差异不显著,表明螯合剂在过量的情况下并不能显著提高Cd的浸提效率;而柠檬酸和HCl对Cd的浸提效率随浓度的升高而增加,尤其在石灰性土壤上,浓度的升高极显著地提高了浸提效率。外源添加Cd污染土壤上Cd浸提效率极显著高于田间无污染土壤。研究结果显示EDTA用于Fe、Ca含量均较低的土壤效果更好,EDDS宜用于有机质和黏粒含量均较低的土壤,而柠檬酸和HCl宜用于酸性土壤。     

EDTA和柠檬酸对污染土壤中重金属的解吸动力学及其形态的影响

利用批处理振荡解吸平衡法研究了0.05 mol/L的乙二胺四乙酸钠(EDTA)和柠檬酸对污染土壤中Cd,Pb,Cu,Zn的解吸动力学特征,并采用优化的BIER(European Community Bureau of Reference)连续提取法分析了EDTA和柠檬酸处理前后土壤中重金属形态和生物有效性的变化.结果表明,污染土壤中重金属Cd,Pb,Cu,Zn的解吸率随着解吸时间的延长而不断增加,但解吸速率随解吸时间的延长而不断降低.EDTA对Pb,Cu的解吸能力显著大于柠檬酸,柠檬酸对Zn的解吸能力显著大于EDTA,柠檬酸和EDTA对Cd的解吸能力相差不大.EDTA和柠檬酸对4种重金属解吸能力的顺序分别为:Pb＞Cd＞Zn＞Cu和CA＞Zn＞Pb＞Cu.双常数方程是描述污染土壤中Cd,Pb,Cu,Zn解吸动力学过程的最佳方程.EDTA去除的重金属主要以酸提取态和可还原态存在,柠檬酸去除的重金属主要以酸提取态存在.EDTA和柠檬酸处理后.污染土壤中Cd,Pb,Cu,Zn的生物有效性降低.     

新鲜土样和改进ASI浸提剂对土壤有效养分测试的影响

通过分析基于风干土样和新鲜土样、ASI（Agro Services International Inc., ASI）浸提剂和改进ASI浸提剂进行测量的土壤有效养分含量的相关性,探索一种基于新鲜土样和联合浸提剂进行土壤有效养分测试的方法。结果表明,利用ASI浸提剂测量的北京潮土新鲜土样的NO3--N和NH4+-N、有效P、K、Ca、Mg、Cu、Fe、Mn、Zn、有机质含量、及pH值,与风干土样的测量值均呈显著的线性相关关系,经该线性方程回归检验的测量相对误差小于5%～9%;利用改进ASI浸提剂测量的新鲜土样和风干土样的NH4+-N、有效P、K、Ca、Mg、Cu、Fe、Mn、Zn含量与基于ASI浸提剂测量的也呈显著的线性相关关系,经该线性方程回归检验的测量相对误差小于5%～8%。因此,基于新鲜土样和改进ASI浸提剂测量石灰性土壤有效养分含量是可行的,可为车载式土壤养分检测提供一种快捷的土样浸提前处理方法。     

Mehlich 3浸提剂在茶园土壤养分分析中的应用

Mehlich 3(M3)浸提剂是一种适合于不同类型土壤、能浸提不同有效态元素的通用浸提剂,而茶园土壤是一类较特殊的酸性土壤,它的强酸性、富铁铝等特性,是否适用M3浸提方式,国内鲜有报导。本文通过对目前较普遍适用茶园土壤的浸提方法与M3浸提剂相比较,结果表明M3浸提茶园土壤各元素有效态含量要高于常用浸提方法,K、Ca、Mg、Cu、Zn、Mn、Cr等元素含量结果相差不大,但Fe含量相差3倍,B、Cd等元素含量结果相差7～8倍,且各元素有效态含量呈极显著正相关。对M3方法及电感耦合等离子体光谱仪(ICP)精密度测定后认为M3方法结合ICP测定精密度高,结果稳定可靠。     

污水灌溉对土壤浸提液元素浓度变化影响的田间试验研究

土壤化学元素的变化趋势关系到污水灌溉农业的可持续性。该文通过田间试验,研究了冬小麦和夏玉米轮作条件下2种灌溉水质和3种灌水量对土壤浸提液元素浓度变化的影响。试验结果表明：在自然降雨条件下,大水量污灌增加土壤盐分而中、小水量污灌则降低土壤盐分。试验用污水不会导致土壤的次生碱化。土壤中的Ca、Mg、Fe和Zn含量在试验期间增加而P、Mn、Cu、Cd和Ni减小。大水量污灌增加土壤中的Na和B含量而小水量污灌则降低其含量;K的变化趋势与其相反。污灌可补充土壤中的作物营养元素K和P,但降低污水灌水定额可有效抑制盐分、B和Zn在土壤以及重金属元素在作物中的累积。     

CaCO_3对Cd和几种营养元素在红壤-黄豆系统中的调控作用

利用盆栽试验,通过研究CaCO3施用对Cd在红壤-黄豆系统中的迁移与分配和对几种营养元素在土壤以及黄豆叶片中含量变化的影响,探讨了CaCO3对Cd和几种营养元素在红壤-黄豆系统中的调控作用。结果表明,CaCO3施用能提高土壤pH值和交换态Ca含量,显著降低土壤交换态Cd含量,有效抑制黄豆植株对Cd的吸收和转运,从而达到修复土壤Cd污染的目的。同时,随着CaCO3施用量的增加,土壤交换态K,Mg,Zn,Mn等营养元素含量下降,黄豆叶片中这些元素含量也同时降低。CaCO3施用虽然能够降低土壤Cd的活性,有效抑制土壤Cd向植物地上部分迁移,显著降低黄豆各器官的Cd含量,但是黄豆叶片中营养元素含量下降的现象应该引起人们的注意。     

李营养累积、分布及叶片养分动态研究

基于保障生态和果品安全以及合理实施果园养分管理的前提,对大石早生李树体各部位营养元素积累、分布以及各营养元素的周年变化规律进行了分析.结果表明:①营养元素在各个器官的相对含量,除K、Zn在果实中含量最高外,N、P、Ca、Mg均以叶片中含量为最高,以叶片做营养诊断是适宜的.②大石早生李树体营养元素N、P、K、Ca、Mg、Fe、Zn的元素比值为10.00:1.26:6.42:12.57:2.46:1.87:0.14.⑧100 kg鲜果的养分吸收量分别为:N 772.47g,P74.25 g,K 730.33g,Ca874.16 g,Mg 169.82 g,Fe 66.05 g,Zn 7.53 g,N:P:K的比例为1.00:0.10:0.95.④N、P、K、Ca、Mg、Fe、Zn、Mn、Cu的含量随物侯期呈规律性变化.生长季初期,N、P、K、Zn、Cu的含量迅速下降,Fe、Mn、Ca、Mg呈逐渐上升的趋势;中期这9种元素总体变化幅度较小;后期Fe,Cu.N、P、K的含量呈下降趋势,Mn、Zn、Ca,Mg依然上升.本结果既丰富了国内李营养理论,同时又为制定合理的施肥措施及建立绿色优质果品科技示范基地提供了理论依据.     

硒对镉胁迫下水稻幼苗叶片元素含量的影响

采用溶液培养研究Se对Cd胁迫下水稻幼苗叶片叶绿素和几种元素含量的影响结果表明,单用Cd处理,高浓度Cd使水稻幼苗叶片Ca、Mg、Fe、Zn、Mn含量显著减少;单用0.10mg/L Se处理可显著增加叶片Fe、Zn、Mn含量。Se使较高浓度Cd(5.0~10.0mg/L)胁迫下水稻幼苗叶片Ca、Mg、Fe、Mn含量高于单用Cd处理,Se与Cd的互作效应影响叶片Ca、Mg、Fe、Zn、Mn含量。叶绿素a/b值不能作为水稻幼苗Cd毒害指标。     

镍污染对小麦幼苗矿质营养元素吸收与累积的影响研究

试验研究Ni胁迫对小麦幼苗茎叶中Cu、Zn、Fe、Mn、Ca和Mg营养元素吸收及累积的影响结果表明 ,Ni胁迫下随土壤施Ni量的增加而小麦幼苗生长受抑 ,生物产量下降 ,小麦幼苗Cu、Fe、Ca和Mg累积量呈下降趋势 ,而Zn、Mn累积量呈增加趋势。小麦幼苗 6种营养元素累积率与其累积量的规律较吻合 ,表明作物受Ni毒害与营养元素代谢平衡失调有关     

当归药材与产地土壤中无机元素的相关分析研究

采用ICP-MS和AAS测定了95批当归药材及其产地土壤中8种重金属元素和7种其他无机元素含量,研究药材与产地土壤中无机元素的相关性。结果表明,当归药材中的特征性无机元素是Fe、Mn、Mg、As、Cr及Ni,土壤中的特征性无机元素是Zn、Mn、Pb、Cr及Ni;当归药材中,无机元素Mn与Zn、Cr、Fe、Cu,Ni与Fe、Cd、Sb、Zn,As与Sb、Pb、Cr、Mn,Cu与Mg、Pb、Zn,Cr与Fe、Pb,Mg与Sb、Zn,以及Ca与Na呈显著正相关,而K与Na、Pb、Cd呈显著负相关;当归对土壤中的Na有富集作用;无机元素Sb、Ca和Na在当归药材与土壤中呈显著正相关。研究发现,中药当归含有丰富的有益无机元素,有害重金属元素含量极低,符合相关标准,在国际贸易及GAP种植方面具有明显的优势和广阔的发展前景。     

Combination of Different Extractants to Assess Binding Forms of Some Elements in Soil Profiles

Abstract

Three different chemical extractants were evaluated as to their extraction efficiency for copper (Cu), zinc (Zn), lead (Pb), aluminium (Al), iron (Fe), chromium (Cr), manganese (Mn), potassium (K), magnesium (Mg), and calcium (Ca) on forest soil profiles from the Romanian Carpathians. The extractants were hot 14 M nitric acid (HNO₃), 0.05 M hydrochloric acid (HCl), and 0.1 M sodium pyrophosphate. By comparing amounts extracted by 0.05 M HCl and 0.1 M sodium pyrophosphate relative to that dissolved by hot 14 M HNO₃, some conclusions were drawn concerning the chemical forms of the metals in the extractable pool. The amount released by 0.05 M HCl was generally less than 10% of the HNO₃‐extractable fraction but showed considerable variation among the elements studied. The relative amount extracted by pyrophosphate increased with organic‐matter content of the soils for Cu, Zn, Pb, Al, Fe, and Cr; stayed more or less constant for Mn, K, and Mg; and decreased for Ca. These findings are discussed with respect to the different binding forms of the metals in the soil and the processes affecting their mobility. From the present results, the metals were ranked as follows with respect to their ability to form organic complexes in natural soils: Cu>Cr, Pb>Ca>Al>Fe, Zn, Mn, K>Mg. However, the use of cold dilute HCl as a fractionation step may be questionable in cases of soils with a high content of substances possessing large neutralization capacity for protons.     

乙二胺四乙酸和柠檬酸活化石灰性土壤磷素的潜力评估

  【目的】  长期施磷形成的高磷残留土壤,面临土壤酸化、钙镁离子淋失等问题。本研究采用肥料中常见的螯合剂乙二胺四乙酸 (EDTA) 和柠檬酸,研究其对不同磷含量的石灰性土壤中磷素的活化作用,以期为磷肥减施和土壤残留磷高效利用提供有效途径。  【方法】  供试低磷、高磷和白云石改良土壤取自北京市房山区的石灰性土壤,3种供试土壤的全磷含量依次为0.95、1.90和1.91 g/kg,有效磷含量依次为7.39、160和152 mg/kg。采用室内往复振荡浸提方法,两种浸提剂为EDTA和柠檬酸,低磷土壤浸提剂浓度为0.05 g/L,浸提时间为12 h,高磷土壤和改良土壤浸提剂浓度均为0.5 g/L,浸提时间分别为12 h和1 h。每个土壤样品采用相同方法连续浸提10次,同时以去离子水浸提作为对照。测定了浸提液中磷、钙、镁、铁、铝含量,计算各元素的单次浸提量和累积浸提量。全部浸提后,用蒋顾磷分组法测定了土壤中不同组分磷的含量。  【结果】  EDTA和柠檬酸在低磷土壤中单次磷素浸提量均较低,且累积浸提量之间差异不显著,连续浸提10次后磷素的累积浸提量不及土壤全磷的3%;而在高磷土壤和施入白云石的改良土壤中,柠檬酸和EDTA的单次磷素浸提量为低磷土壤的7～64倍,磷素累积浸提量超过土壤总磷的20%,且柠檬酸处理高于EDTA处理。在低磷土壤中,磷素的累积浸提量仅与铁和铝离子的累积浸提量显著相关,在高磷土壤中,磷素的累积浸提量与钙、镁、铁和铝离子的累积浸提量均显著正相关,且相关系数均在0.78以上,而在白云石改良土壤中,磷素的累积浸提量与铝离子的累积浸提量之间无显著相关关系。进一步分析浸提前后土壤磷素组分变化可知,在低磷土壤中,去离子水、EDTA和柠檬酸经10次浸提后土壤Ca₂-P显著增加;在高磷土壤中,EDTA和柠檬酸处理浸提的土壤Ca₂-P、Ca₈-P较去离子水处理显著降低了16.1%、14.9%和37.1%、5.4%。此外,柠檬酸处理还降低了31.4%的土壤Al-P,EDTA和柠檬酸在改良土壤上对于各组分磷的浸提量与在高磷土壤上相似。  【结论】  在连续浸提的条件下,EDTA 和柠檬酸在低磷土壤上无明显活化磷素的效果,而在高磷土壤上和施入白云石的改良土壤上则可持续浸提出大于总磷量20%的磷素。高磷土壤和改良后土壤中被浸提磷素主要来自Ca₂-P和Ca₈-P,少部分来自Al-P和Fe-P。     

Nutrient mobilization and nutrient contents of Zea mays in response to EDTA additions to heavy‐metal‐contaminated agricultural soil

Enhanced phytoextraction of heavy metals (HMs) using chelating agents and agricultural crops is widely tested as remediation technique for agricultural soils contaminated with less mobile HMs. Nutrients are complexed by chelating agents simultaneously to HMs. In this study, the effect of EDTA (ethylenediaminetetraacetic acid) application on nutrient mobility in the soil and nutrient contents of Zea mays was tested on the laboratory and on the field scale. EDTA effectively increased the mobility of total water‐soluble macronutrients (Ca, K, Mg, P) and micronutrients (Fe, Mn) in the soil solution. Thereby nutrient co‐mobilization did cause competition to target HMs during the phytoextraction process. Mobilization was caused by complexation of nutrient cations by negatively charged EDTA and by dissolution of oxides and hydroxides. Increased concentrations of negatively charged P indicate the dissolution of metal phosphates by EDTA. Higher total water‐soluble nutrient concentrations enhanced bioavailability and plant contents of all determined nutrients especially that of Fe. Mobilization of nutrients may result in leaching and loss of soil fertility.     

Comparison of Four Different Extraction Methods to Assess Plant Availability of Some Metals in Organic Forest Soil

Abstract

The objective was to find an uncomplicated test giving the best correlation between calcium (Ca), magnesium (Mg), manganese (Mn), copper (Cu), zinc (Zn), and lead (Pb) extracted from humic forest soil and the total concentration of the element in some understorey forest plants using well‐known extractants. The elements were selected because Ca, Mg, Mn, Cu, and Zn are essential nutrients to plants and Zn and Pb are potentially harmful heavy metals received over the years in the southern parts of Norway by long‐range atmospheric transport. Extraction of organic podzolic surface soil (Oe and Oa horizon) from 17 different pine forests in central and southern Norway was carried out with four different reagents to evaluate uptake of Ca, Mg, Mn, Cu, Zn, and Pb in the understorey plants Deschampsia flexuosa, Vaccinium myrtillus (leaves and stems), and Vaccinium vitis‐idaea (leaves and stems). The NH₄OAc, NH₄NO₃, HCl, and EDTA solutions used to extract the soil in addition to concentrated HNO₃, demonstrated variability in capacity to extract the different elements from the soil. The extractants yielded significant relations between concentrations of Ca, Mn, and Pb in the Oe or Oa horizon and some of the plants or plant compartments, even though distinct correlation was more dependent on species and plant part than the actual extractant used. In the case of Zn, Cu, and Mg only a few sporadic correlations were observed between the different plant/plant compartments and the element concentrations in the soil extracts. Altogether none of the extractants was shown to be superior to the others in providing the best correlation with the elements concentrations in selected plant/plant compartments. In the case of Ca, Mn, and Pb all the extractants including concentrated HNO₃ provided significant correlations with at least some of the selected plant/plant compartments.     

温州蜜柑叶片黄化果园土壤及叶片的养分含量特征

弄清叶片黄化柑橘园土壤与叶片的养分含量特征,为改善柑橘园营养状况,提高柑橘产量和品质提供理论与技术支撑。通过对黄化和无黄化温州蜜柑园土壤、叶片的养分含量进行分析,研究影响温州蜜柑叶片黄化的关键因子。结果表明,温州蜜柑叶片的钙、镁、硼含量与SPAD值呈显著或极显著正相关,叶片黄化是由叶片中钙、镁、硼含量不足所造成的,属于综合缺素型,同时叶片中钾、铁、锰含量较高,叶片对钙、镁、硼的吸收与对钾、铁、锰的吸收之间存在相互拮抗的关系;土壤酸化是叶片黄化的主要驱动因子,pH值较低一方面降低了土壤中钙、镁、硼的有效性,另一方面,土壤中较高的铁、锰含量抑制了柑橘对钙、镁、硼的吸收,最终导致叶片因缺钙、缺镁、缺硼而出现黄化。喷施含钙、镁、硼的叶面肥料,防止土壤酸化是改善温州蜜柑叶片黄化的有效措施。     

Evaluation of four chemical extractants for metal determinations in wetland soils

Abstract

Wetland soils (hydric soils) are unique in their chemical characteristics compared to upland soils. It is known that they are capable of removing a variety of wastes from polluted water entering the wetland including metals and potentially toxic heavy metals. When these metals are determined in wetland soils, it is necessary to use the proper chemical extractant(s). Four commonly used chemical extractants (Mehlich 1, Mehlich 3, 0.1M HCl, and DTPA) for soil fertility evaluation were selected to measure metal concentrations of three different wetland soils/spoils. Soil samples were collected from the constructed wetland cells which were lined with Abernathy silt loam topsoil and two different mine spoil materials [collected from active coal strip‐mined sites in Alabama (pH 5.9) and Tennessee (pH 3.2)]. Mehlich 3 extracted the most zinc (Zn), iron (Fe), manganese (Mn), calcium (Ca), magnesium (Mg), potassium (K), sodiumm (Na), and aluminum (Al), while 0.1M HC1 extracted more cadmium (Cd), copper (Cu), and lead (Pb). Extractants followed the same trend in removing quantities of the metals from the three soil/spoil materials, with DTPA generally extracting the least amount of the metal (the trend was Mehlich 3 > 0.1N HCl > Mehlich 1 > DTPA). However, DTPA removed larger quantities of metals from Tennessee spoil compared to Alabama spoil and topsoil, suggesting the higher effectiveness of DTPA under acidic conditions. Metal concentrations in plant tissue did not show a definite trend in correlation with metals extracted by the four chemical extractants.     

EDTA Extraction of Heavy Metals from Different Soil Fractions and Synthetic Soils

A laboratory-prepared contaminated soil was partitioned into four fractions, namely carbonate, Fe/Mn oxides, organic matter and clay mineral, according to the form in which the heavy metal bound with soil constituents. Individual contaminated soil fractions and synthetic soils were prepared for the study of soil extraction using ethylenediaminetetraacetic acid (EDTA). The effect of contact time and EDTA concentration were evaluated for both individual soil fractions and synthetic soils. The extraction reached equilibrium rapidly, after about 30 min. A 0.01 M EDTA solution was less effective than a 0.05 M or a 0.10 M EDTA. EDTA was proved to be effective for metal removal from the four individual soil fractions and synthetic soils. In general, approximately 90% of metals were removed from synthetic soils by 0.10 M EDTA. EDTA extraction of Pb from a contaminated carbonate fraction was thought to be affected by the formation of lead carbonates. A simple equation based on the sum of the released heavy metal from the individual components is used to check if there are interactions among the different soil components when mixed. The estimated values agreed well with the experimentally measured results only for the 0.10 M EDTA system.     

Potassium fixation of some calcareous soils after short term extraction with different solutions

This investigation was done to determine the release of potassium (K) from five calcareous soils of southern Iran using 0.025 M CaCl₂, HCl and citric acid during six successive extractions and to study the K fixation capacity of the soils after K release experiment. Mineralogical study indicated that Vertisols and Mollisols were dominated with smectites; while other soils had illite, chlorite, palygorskite and smectite. Results indicated that citric acid extracted more K than CaCl₂ and HCl (137 vs. 111 and 113 mg kg^?1, respectively). The analysis of calcium (Ca), magnesium (Mg) and K concentrations in the solutions suggests that the exchange of K with soluble Ca and Mg (originated from dissolution of carbonates by acidic solutions) is the main mechanism of K release, but citrate is able to dissolve K-bearing minerals and release K in slightly calcareous soils. Soils with more illite released more K. Potassium fixation capacity of soils increased after extractions of soils with different extractants from 324 to 471 mg kg^?1, with no significant difference. It is suggested to apply more K fertilizers in K-depleted calcareous soils and use of different solutions for extracting K from soil minerals may be a temporary and short term solution.     

重金属高污染农田土壤EDTA淋洗条件初探

通过室内振荡淋洗试验研究了乙二胺四乙酸二钠(EDTA)浓度、淋洗时间、液固比、淋洗次数对甘肃省白银市某高污染农田土壤中重金属去除效果的影响,并测定了EDTA淋洗前后土壤中重金属形态的变化。结果表明：淋洗剂浓度和液固比越高、淋洗时间越长、淋洗次数越多,对重金属的去除效果越好。在EDTA浓度为5 mmol/L、液固比为2.5、连续振荡淋洗3次、每次1 h时,对土壤中Cd、Cu、Pb、Zn 4种重金属的总去除率分别为 55.2%、21.9%、19.3% 和20.9%,其中Cd 淋洗效率最高。EDTA对土壤中交换态、碳酸盐结合态和铁锰氧化物结合态重金属的去除效果明显,但不能有效去除有机及硫化物态和残余态土壤重金属。     

三种无机萃取剂去除土壤中PbCd的条件研究

通过对重金属污染土壤的萃取实验,比较了HCl、Na2S2O3、CaCl2 3种常用无机萃取剂对重金属Ph和cd的萃取效果,并通过改变萃取条件（萃取剂浓度、时间、固液比、萃取次数和温度）,以期找到各种萃取剂达到最大萃取效率时所需的萃取条件。结果表明,萃取剂浓度对于萃取效率的影响最大,随着浓度的提高,3种萃取剂对Ph、Cd的去除作用增强;固液比和萃取次数对Ph、Cd的去除率也有较大的影响;时间对两金属的去除率也有一定的影响,但在本实验条件下,达到萃取平衡所需时间很短;温度对萃取效率的影响很小。本实验中,HCl去除Pb、Cd的能力远远大于其他两种萃取剂。对Cd进行萃取时,需增加萃取次数才能达到较好的萃取效果。