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1.
张晶  苏德纯 《农业环境保护》2012,(10):1927-1932
通过土壤培养试验和生物盆栽试验,研究不同镉污染土壤上作物秸秆炭化后还田对不同镉污染土壤中镉的赋存形态和生物有效性影响,结果表明:在碱性的镉污染土壤上,秸秆炭化后还田降低了玉米地上部生物量,但对玉米地上部镉含量和镉吸收量无显著影响;在酸性的模拟镉污染土壤上秸秆炭化后还田对玉米生长无影响,但还田含镉的油菜秸秆黑炭显著增加了玉米地上部镉含量和镉吸收量;还田不含镉的玉米秸秆黑炭对镉污染土壤中DTPA提取态镉含量没有明显影响,但还田含镉的油菜秸秆黑炭显著增加了镉污染土壤中DTPA提取态镉含量;施用含镉的油菜秸秆黑炭增加了镉污染土壤中水溶和交换态镉含量;施用玉米和油菜秸秆黑炭均显著降低了模拟镉污染土壤中水溶和交换态镉含量;增加了松有机结合态、碳酸盐结合态和紧有机结合态镉含量;模拟镉污染土壤施用玉米和油菜秸秆黑炭6个月后土壤中水溶和交换态镉仍然是土壤镉的主要赋存形态,水溶和交换态镉占土壤全镉的70%以上。综合以上结果可知,秸秆黑炭不能降低污染土壤中镉的生物有效性和植物对土壤镉的吸收量。  相似文献   

2.
在分析成都平原核心区土壤重金属(Cd、Cr、Pb、Cu、Zn)全量、各形态含量及相应点位种植的水稻籽实重金属含量的基础上,通过统计分析、空间插值及线性回归方程的模拟,研究了土壤Cd、Cr、Pb、Cu、Zn全量的空间分布状况、各形态重金属含量统计特征,以及水稻籽实对重金属各形态的累积差异及其影响因素。结果表明,成都平原水稻土重金属污染较轻,除Cd外,均低于国家土壤环境质量二级标准。土壤中重金属的可交换态含量均较低,Cd主要以铁锰氧化态存在,Cr、Cu、Zn、Pb主要以残渣态存在。水稻籽实对5种重金属的累积效应顺序为:Cd>Zn>Cu>Pb>Cr。与水稻重金属累积关系密切的重金属活性形态(可交换态、碳酸盐结合态、铁锰氧化物结合态和有机物结合态)主要有:Cd的碳酸盐结合态、Cr的可交换态、Pb的有机物结合态和Cu的碳酸盐结合态含量;Zn各活性形态对水稻籽实含量的影响不明显。土壤理化性质对不同活性形态重金属元素的影响效应各不相同。活性态Cd主要受有机质、pH和容重的影响;活性态Cr与pH、有机质、CEC和容重密切相关;活性态Pb与有机质、容重、中细粉粒、砂粒等均有密切的关系;Cu的活性主要受粘粒、有机质含量的影响;Zn的有效性主要受pH、有机质、砂粒、容重的影响。总的看来,对土壤Cd、Cr、Pb、Cu、Zn各活性形态含量影响效应较强的是有机质、pH、容重,而与土壤吸附性能密切相关的颗粒组成、CEC的影响不甚明显。  相似文献   

3.
水稻子实对不同形态重金属的累积差异及其影响因素分析   总被引:3,自引:0,他引:3  
在分析成都平原核心区土壤重金属(Cd、Cr、Pb、Cu、Zn)全量、各形态含量及相应点位种植的水稻子实重金属含量的基础上,通过统计分析、空间插值及线性回归方程的模拟,研究了土壤Cd、Cr、Pb、Cu、Zn全量的空间分布状况、各形态重金属含量统计特征,以及水稻子实对重金属各形态的累积差异及其影响因素。结果表明,成都平原水稻土重金属污染较轻,除Cd外,均低于国家土壤环境质量二级标准。土壤中重金属的可交换态含量均较低,Cd主要以铁锰氧化态存在,Cr、Cu、Zn、Pb主要以残渣态存在。水稻子实对5种重金属的累积效应顺序为:Cd>Zn>Cu>Pb>Cr。与水稻重金属累积关系密切的重金属活性形态(可交换态、碳酸盐结合态、铁锰氧化物结合态和有机物结合态)主要有:Cd的碳酸盐结合态、Cr的可交换态、Pb的有机物结合态和Cu的碳酸盐结合态含量;Zn各活性形态对水稻子实含量的影响不明显。土壤理化性质对不同活性形态重金属元素的影响效应各不相同。活性态Cd主要受有机质、pH和容重的影响;活性态Cr与pH、有机质、CEC和容重密切相关;活性态Pb与有机质、容重、中细粉粒、砂粒等均有密切的关系;Cu的活性主要受粘粒、有机质含量的影响;Zn的有效性主要受pH、有机质、砂粒、容重的影响。总的看来,对土壤Cd、Cr、Pb、Cu、Zn各活性形态含量影响效应较强的是有机质、pH、容重,而与土壤吸附性能密切相关的颗粒组成、CEC的影响不甚明显。  相似文献   

4.
采用盆栽试验及连续浸提形态分级方法,研究了Cd和Pb在土壤中的形态分布规律及其对油菜的生物有效性的影响。结果表明,当土壤受外源Cd/Pb污染后,重金属的形态分布特征发生了变化,以可交换态(EXC)响应最大,Cd、Pb的赋存形态分别以碳酸盐结合态(CAB)、铁锰氧化态(FMO)和碳酸盐结合态(CAB)为主;一定浓度范围内的Cd/Pb复合胁迫能促进油菜的生长,油菜根系和茎叶的Cd、Pb含量均随着Cd/Pb复合胁迫水平的升高而持续增加。茎叶中的Cd含量远远高于根系,Pb含量反之。油菜可将更多的Cd从根系转移至茎叶,而将更多的Pb滞留在根系中;对油菜根系吸收Cd最重要的形态为可交换态(EXC)和碳酸盐结合态(CAB),而对茎叶吸收Cd以及油菜吸收Pb贡献最大的则为碳酸盐结合态(CAB)。  相似文献   

5.
氮肥对油菜根-土界面镉迁移及镉组分变化特征的影响   总被引:6,自引:0,他引:6  
利用盆栽试验研究了不同形态氮肥对镉污染土壤油菜根土-界面pH、油菜生长、镉迁移及镉组分变化特征的影响.结果表明,不同形态的氮对油菜地上部Cd积累有显著的影响,施用铵态氮肥可以显著提高油菜地上部Cd含量,而施用硝态氮肥则对地上部Cd含量没有明显的影响.铵态氮肥能显著降低油菜根际pH,使得油菜根际残渣态、碳酸盐态和铁锰结合态Cd强烈活化,促使这三种形态Cd向交换态转换,从而增加了Cd的生物有效性.  相似文献   

6.
施用生物炭和石灰对土壤镉形态转化的影响   总被引:1,自引:0,他引:1  
通过室内培养试验,比较石灰、生物炭及生物炭和石灰配施3种改良剂作用下镉污染草甸土中土壤镉各形态转化以及pH的影响。结果表明,土壤添加生物炭培养60d,土壤pH呈随时间增加逐渐增加的趋势,而添加石灰和生物炭与石灰配施处理,土壤pH呈现先增加至最大值而后缓缓降低趋于稳定的趋势,但均显著高于对照。各改良剂的施用均显著降低土壤可交换态Cd含量,与CK处理相比,添加生物炭、石灰和生物炭石灰混合改良剂后,土壤可交换态Cd含量分别降低8.6%~13.7%,17.8%~21.7%和18.4%~23.3%。相关分析结果表明,土壤可交换态Cd含量与土壤pH之间均存在极显著的负相关关系(R2=0.74)。土壤添加改良剂后,显著降低土壤可交换态Cd比例,增加碳酸盐结合态、铁锰氧化物结合态、有机结合态和残渣态Cd比例,从而降低土壤重金属的生物有效性。  相似文献   

7.
通过温室土培盆栽试验,研究了重金属镉污染土壤上连作油菜及施用堆肥对土壤中镉赋存形态及生物有效性的影响。结果表明:(1)在油菜连作体系下,施用堆肥显著降低油菜地上部镉含量。施用堆肥改变了土壤镉赋存形态,显著降低土壤易溶态和碳酸盐结合态镉含量而增加土壤铁锰氧化物结合态镉含量,从而降低土壤镉的生物有效性。(2)在相同堆肥处理下,种植两茬油菜后的土壤易溶态和碳酸盐结合态镉含量与不种植油菜的处理相比显著降低;而土壤硫化物及有机结合态镉含量较对照有所上升,种植油菜对土壤铁锰氧化物结合态镉和残渣态含量影响不显著,但是不同积累镉能力油菜朱苍花籽和川油Ⅱ-93之间对土壤镉形态的影响差异不显著。  相似文献   

8.
钝化剂-锌肥降低烟草镉含量长期效果研究   总被引:5,自引:0,他引:5  
采用田间小区试验,通过外源添加1.5 mg kg-1镉(Cd)模拟轻度Cd污染土壤,研究赤泥、油菜秸秆、玉米秸秆及其组合并配施硫酸锌降低土壤Cd有效性和烟草各部位Cd含量的长期效果。结果表明,施用钝化剂后,烟叶产量增加了7.0%~32.1%,中上等烟叶比例提高了2.9%~20.2%,烟草经济效益提高了6.6%~31.3%。钝化剂处理土壤有效态Cd含量降低显著,2012年和2013年降幅分别为18.6%~47.4%、16.0%~27.0%。烟草各部位Cd含量排序为下部叶中部叶、上部叶茎秆,且均与土壤有效态Cd含量呈极显著正相关关系。2011—2013年钝化剂处理烟草叶片Cd平均含量较对照分别降低了28.3%、28.1%、15.2%,烟草各部位Cd含量年变化幅度下部叶最大,茎秆最小,叶位间Cd含量差异随钝化时间延长逐渐缩小。钝化剂降低土壤-烟草系统Cd生物有效性效果稳定持久,其中油菜秸秆优于玉米秸秆,有机无机复合钝化剂效果最好。配施锌肥后,2011—2013年烟草叶片Cd含量较对照分别降低了19.1%、23.3%、17.9%,且下部和中部叶片降低效果达到显著水平;中部和上部叶Cd、Zn含量呈显著负相关关系。因此,在轻度Cd污染土壤上,赤泥油菜秸秆复合钝化剂配施锌肥是降低烟叶镉含量兼顾高产的最佳生产措施。  相似文献   

9.
泉州走马埭典型土壤重金属的赋存形态分析   总被引:5,自引:3,他引:2  
何园  王宪  陈丽丹  郑盛华  蔡真珍 《土壤》2007,39(2):257-262
采用改进的Tessier连续萃取方法研究了泉州走马埭国家农田示范保护区典型土壤中重金属(Cr、Ni、Cu、Zn、Cd、Pb)的化学形态分布,通过土壤重金属的赋存形态分析比较了6种重金属的生物可利用性。研究结果表明,土壤中不同重金属元素化学形态分布具有不同的特点:Cr和Ni主要以残渣态存在,其余形态所占的比例很小;Cu以残渣态含量最高,碳酸盐结合态含量最低;Zn以残渣态为主,可交换态含量最低;Cd以可交换态和碳酸盐结合态为主,水溶态含量最低;Pb以残渣态和铁锰氧化物结合态为主,水溶态含量最低。土壤中除Cd外,Zn、Cu、Cr、Pb、Ni在正常自然条件下相对比较稳定。  相似文献   

10.
采用田间试验研究了施加不同用量(2、4、8、16 t·hm~(-2))的脱硫石膏对紫色水稻土重金属(Cd、Pb、Zn、Cu)全量、形态分布和水稻重金属吸收及分配的影响,为脱硫石膏农用的安全性提供科学依据。结果表明:施加脱硫石膏后,土壤Pb全量较对照显著增加14.00%~68.77%(P0.05),脱硫石膏用量低于4 t·hm~(-2)时土壤Cd全量与对照差异不显著,超过该用量时Cd全量较对照显著增加16.28%~19.94%,而土壤Zn、Cu全量与对照无显著差异,且土壤重金属全量均符合《土壤环境质量标准》(GB 15618—1995);同时施加脱硫石膏后,土壤中Cd可交换态占比降低,残渣态占比增高,并促进Pb的可交换态向有机结合态和铁锰氧化态转化,Zn铁锰氧化态占比增高,对Cu的赋存形态无明显影响;脱硫石膏处理组水稻根、茎叶和籽粒中重金属含量有不同程度的降低,水稻根、茎叶及籽粒对Cd、Pb的富集系数下降,且籽粒中Cd、Pb、Zn、Cu含量均符合我国《食品安全国家标准食品中污染物限量》(GB 2762—2012)。水稻各部分对Cd、Pb的积累与其可交换态、碳酸盐结合态、铁锰氧化态和有机结合态含量均呈正相关,其中籽粒Cd含量与可交换态Cd含量呈极显著正相关(P0.01)。在脱硫石膏2~16 t·hm~(-2)用量范围内,稻田土壤Cd、Pb全量有所增加,Zn、Cu全量无变化,Cd、Pb赋存形态向稳定态转化,水稻各部分Cd、Pb、Zn、Cu含量有不同程度降低,脱硫石膏可在水稻田安全利用。  相似文献   

11.
采用BCR(community bureau of reference)连续提取法对大宝山矿山槽对坑尾矿库尾砂和周边农田土壤重金属Cd、Pb、Cu和Zn的形态分布及其生物有效性进行了分析。结果表明,尾砂中Cd、Pb、Cu和Zn残渣态占绝对优势,占其总量的百分数均在85%以上。农田土壤中Cd、Cu和Zn都以残渣态为主,分别占其总量的60%、60%和90%以上,Pb以残渣态和可还原态为主,占其总量的93.44%。农田土壤重金属有效性较尾砂大,尾砂和农田土壤重金属生物有效性均以Pb为最高。  相似文献   

12.
原位化学钝化技术是修复重金属污染土壤的重要途径之一,通过施入一些钝化剂以降低土壤中重金属有效态含量,从而减少其迁移及对植物的毒害。选取羟基磷灰石(HA)、磷矿粉(PRX和PRH)、沸石、赤泥、新鲜植物残体、玉米秸秆粉末以及相应的处理共21种钝化剂,在同一培养条件和添加浓度下,比较其对人工Cd污染土壤中可交换态Cd含量的影响,并分析了其在不同培养时间对钝化效果的时间效应,试验的结果对于筛选Cd污染土壤钝化剂有着重要的意义。结果表明,纳米化赤泥、羟基磷灰石和纳米化酸洗赤泥可显著降低土壤中可交换态Cd含量,钝化比例高达35%-55%;赤泥、酸洗赤泥、沸石达15%-25%;富含巯基植物蒜苗、油菜、大葱植物残体也可达20%-25%。磷矿粉、大葱粉末、玉米秸秆和巯基化玉米秸秆的钝化效果相对较差;HA、铵型沸石、纳米赤泥、酸洗纳米赤泥、干油菜粉末、酸洗赤泥对可交换态Cd的钝化效果的时间效应不明显;赤泥、大葱残体、特别是玉米秸秆和巯基玉米秸秆随时间增长钝化效果增加显著,在8周和16周时段钝化效果较好。  相似文献   

13.
Creation of Technosols with the use of different materials is a sustainable strategy to reclaim mine tailings and reduce metal mobility. For this purpose, a short‐term incubation experiment was designed with biochars derived from pig manure, crop residues and municipal solid waste added to tailings alone or in combination with marble waste. We aimed to assess the efficiency of the different amendments to decrease Cd, Pb and Zn availability in the Technosols and the fractions where metals were retained. Results showed that all amendments reduced metal mobility, directly related to increases in pH. Those materials with higher content of carbonates were more effective to immobilize metals (~99%). Municipal solid waste was highly effective to decrease metal mobility owing to the higher carbonate content, but addition of marble waste was needed to enhance metal immobilization with pig manure and crop residue. Decreases in Cd mobility were related to retention by the carbonate, Mn/Fe oxides and oxidizable (organic compounds) fractions. Decreases in Pb mobility were related to retention in the Mn/Fe oxides and residual fractions, while decreases in Zn mobility were related to retention in Mn/Fe oxides and oxidizable fractions. Association of Zn and Pb with the oxidizable fraction was also related to the recalcitrance of the organic compounds and so dependent on biochar type. Scanning electron microscopy coupled with energy dispersive X‐ray showed that biochar showed great affinity to interact with iron oxides, calcium sulfates and phyllosilicates. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

14.
秸秆还田是我国培肥地力和增加农田土壤碳固定的重要措施,但进入农田的秸秆存在着活化土壤重金属的风险。为了解不同来源的秸秆对污染水平不同农田土壤重金属活性的影响,采取相应措施防止因秸秆还田对农田土壤重金属的激活,开展了盆栽和田间小区试验研究秸秆还田配施石灰对水田土壤铜、锌、镉、铅活性的影响。盆栽和田间试验在轻度和重度污染2种土壤上同时进行。盆栽试验中施用秸秆包括重污染水稻秸秆、轻污染水稻秸秆和轻污染油菜秸秆3种,石灰用量设对照(0 kg·hm-2)和石灰处理(750 kg·hm-2)2个处理;田间小区试验设对照(不施秸秆和石灰)、秸秆还田及秸秆还田+石灰3个处理。动态观察了试验过程中土壤有效态重金属、重金属形态及水稻籽粒中重金属积累情况。结果表明,试验初期(前20 d)秸秆还田显著增加了水田土壤中水溶性有机碳与水溶性重金属的含量;与对照处理比较,水溶性重金属含量以重度污染土壤增幅较为明显。试验后期(60 d后)秸秆还田对土壤重金属的活性的影响逐渐变得不明显。油菜秸秆还田土壤中水溶性重金属含量低于水稻秸秆还田,重污染水稻秸秆还田土壤中水溶性重金属含量高于低污染水稻秸秆还田。盆栽试验和田间试验的结果都表明,重污染水稻秸秆还田可轻微增加水稻籽粒中镉的积累,但轻度污染水稻秸秆还田与油菜秸秆还田对水稻籽粒镉积累的影响较小;3种秸秆还田对水稻籽粒铅、铜、锌积累的影响不明显。配施石灰可显著降低土壤中水溶性重金属的含量,降低水稻籽粒中重金属的积累。研究认为,在污染农田管理上应控制重污染水稻秸秆还田,在秸秆还田的同时适量配施石灰。  相似文献   

15.
A tri-state mining region, including parts of Missouri, Oklahoma, and Kansas, was the site of intense lead and zinc mining and smelting activity until the 1950's. A study was initiated to characterize the heavy-metal contamination of soils in this area. Water-soluble, an index of plantavailable, total, and sequentially extractable metals; organic, and total carbon; and saturated paste pH were determined for mine tailings and soil samples. Mine tailings contained 81 to 89 mg kg?1 total Cd, 1 150 to 1 370 mg kg?1 total Pb, and 11 400 to 13 700 mg kg?1 total Zn. Total concentrations in soil samples were 15 to 86 mg kg?1 Cd, 35 to 1 620 mg kg?1 Pb, and 99 to 18 500 mg kg?1 Zn; and, DTPA extractable concentrations ranged from 0.6 to 10 mg kg?1 Cd, 7.8 to 68 mg kg?1 Pb, and 33 to 715 mg kg?1 Zn. Samples were sequentially extracted to approximate the proportions of the metals in the sulfide, carbonate, organic, sorbed, and exchangeable fractions. For Zn and Cd, concentrations were greatest in the sulfide fraction followed by carbonate, organic, sorbed, and exchangeable. Lead followed the same pattern, except higher concentrations were observed in the sorbed than the organic fractions.  相似文献   

16.
Lead-zinc mine tailings from the ‘old lead-belt’ in Missouri were chemically characterized using total chemical analysis and sequential extraction. These tailings have been considered as an inert and safe material for years. However, the levels of heavy metals in these tailings were found elevated with Pb values as high as 5000 ppm. The sequential extraction results indicated that the Pb was primarily found in the residual fraction and probably is in the PbS form. Some Pb was found in the oxide fraction. Cu, Zn, and Cd were found in several different fractions, but primarily in the residual fraction. Some Cu was found in the organic fraction. The Zn showed a wide variation between samples with high levels in the carbonate, oxide and residual fractions. Very little Pb, Cd, Cu, and Zn was leached by water. The heavy metals in these tailings do appear to be in the more inert forms and should not be readily available to the environment unless there is an interaction of the tailings with acids, microorganisms or chelating materials. The breathing and ingestion of this material may provide such an environment for such interactions and these materials should still be considered dangerous and managed properly.  相似文献   

17.
For the purpose of studying the contamination, bioaccumulation and transfer of heavy metals and understanding the effects of soil properties on these, the work was carried out on a regional scale. A total of 30 sets of soil and pairing rice tissues samples (root, straw and grain) were collected in Xiangzhou of Guangxi, China; soil properties and Cd, Cu, Pb and Zn of different rice tissues were analyzed. The mobility and bioaccumulation of Cd, Cu, Pb and Zn were assessed by transfer coefficients and bioaccumulation factors of them. The results indicated that the excess proportions of Cd and Pb were 50%, 3.33% and 30%, 6.67% in soil and rice grain, respectively, according to Chinese maximum permitted concentrations of heavy metals. Cd and Zn showed stronger bioaccumulation and mobility capability; the bioaccumulation and transfer of Cu were slightly lower than Cd and Zn; Pb had the weakest mobility. The bioaccumulation and mobility of heavy metals from soil to rice were restrained by soil pH, CaO, SOC, Fe oxides and Mn.  相似文献   

18.
采用盆栽试验方法,研究了污泥改良锰矿尾渣对紫茉莉(Mirabills jdapa)、青葙(Celosia argentea)、一串红(Salviasplendens)和鸡冠花(Celosia cristata)4种花卉植物生长及其富集铅、镉、锌和锰的影响。结果表明,添加污泥增加基质的EC值、总氮、总磷、总钾和有机质含量,而降低铅、镉、锌和锰含量。紫茉莉与青葙生物量、株高和根长大于一串红和鸡冠花。紫茉莉根部铅、镉和锰含量分别为3110.93~4189.16、300.28~399.16和31100.93~36809.77mg·kg-1,都远高于其地上部分含量。青葙根部铅含量超过1000mg·kg-1,而其地上部分含量少;其地上部分镉和锰含量分别为322.13~441.88和21888.54~26511.31mg·kg-1,都大于其根部含量,青葙具有镉和锰超富集植物的特性。污泥改良锰矿尾渣促进这4种花卉植物生物量、株高和根长增加。除紫茉莉锌含量外,添加污泥改良锰矿尾渣增加这4种花卉植物的铅、镉、锌和锰含量。在锰矿尾渣污染区进行植物修复时,采用紫茉莉、青葙和添加污泥强化植物修复效率可行。  相似文献   

19.
The geochemical behavior of metals, including Fe, Mn, Pb and Zn, in contaminated paddy soils was investigated during the cultivation of rice crops through laboratory microcosm experiments. From the two paddy fields contaminated by mine tailings, Siheung and Deokeum in Korea, paddy soils were collected and analyzed for their geochemical characteristics. The Siheung paddy soil showed higher levels of heavy metals, whereas the higher potential for the release of metals was anticipated due to the extremely acidic conditions at Deokeum. In microcosm experiments of flooded paddy soils over 18 weeks, Fe and Mn were released in subsurface pore waters by reductive dissolution, and Pb and Zn were dissolved in high amounts at the surface by oxidation of sulfides. Although amorphous Fe oxide-rich layers were formed at the surface of both paddy soils, the release of Pb and Zn were controlled at the surface by these layers only under slightly alkaline conditions at Siheung. Lead and Zn were associated with the reducible and carbonate fractions at the surface paddy soil of Siheung from the sequential extraction on core samples collected during the flooded period. In the acidic conditions at Deokeum, Pb and Zn were continuously released until the late stage of flooding. A great increase in the exchangeable fraction of metals was observed after the soils had drained. The bioavailability of metals for rice crops would be high under acidic conditions at Deokeum, despite the lower levels of heavy metal contamination.  相似文献   

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