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有机肥在改良土壤的同时也会改变农药的环境行为. 为明确施加牛粪有机肥对灰钙土吸附阿特拉津(ATZ)的影响作用及机制,采用批平衡试验,分析其吸附动力学、热力学以及牛粪施加量、pH、离子强度等因素对ATZ吸附的影响. 结果表明:①ATZ在灰钙土与施加牛粪灰钙土上的吸附均可分为快吸附、慢吸附直至平衡的过程,准二级动力学模型可较好地描述其吸附过程,施加有机肥增加了ATZ在灰钙土上的平衡时间,吸附速率受颗粒内扩散和外部液膜扩散共同控制. ②施加牛粪有机肥后,灰钙土对ATZ的吸附热力学更符合Freundlich模型,1/n在0.42~0.64之间,吸附属“L型”模式,低温和高温均会抑制ATZ在灰钙土上的吸附. ③pH和共存离子是影响ATZ在灰钙土上吸附的重要因素,随pH的升高,ATZ在灰钙土与施加牛粪灰钙土上的吸附量降低,这是由于碱性情况下,ATZ以阴离子存在,与带负电的灰钙土产生静电排斥作用;灰钙土施加牛粪有机肥后,共存阳离子对ATZ的吸附抑制作用明显,增加离子强度可能导致竞争吸附的存在,从而抑制有机离子在灰钙土上的吸附,且离子浓度越高,抑制越明显. 研究显示,土壤施加牛粪有机肥后,ATZ的吸附量增加,吸附由疏水性分配转变为多分子层化学吸附为主,表明施加牛粪有机肥会改变ATZ在灰钙土上的吸附行为和机制,降低ATZ在灰钙土中的迁移风险. 研究结果将为贫瘠黄土土壤改良风险和三嗪类农药的管控提供理论依据. 相似文献
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农田灰钙土中有机质和碳酸钙对Zn吸附-解吸行为的影响 总被引:3,自引:0,他引:3
采用序批平衡法,研究了Zn在去除有机质及去除碳酸钙前后灰钙土的吸附-解吸行为.结果表明,在试验土壤中吸附量均随着加入Zn浓度的增加而增加,且去碳酸钙土对Zn吸附固定能力明显低于灰钙土,即有机质对灰钙土Zn的吸附影响小于碳酸钙;去有机质及去碳酸钙前后灰钙土对Zn的吸附过程不适合用 Langmuir方程描述,而 Freundlich方程能够很好地拟合,调整后的决定系数R2¢均大于0.90,达到极显著水平(P<0.01);去除有机质和碳酸钙后灰钙土对Zn的解吸率都升高,且灰钙土去碳酸钙后解吸率略高于去有机质;去除有机质及碳酸钙前后灰钙土的解吸量均随吸附量的升高而升高,且去碳酸钙土解吸量最大,去有机质土次之,灰钙土最小;土壤有机质和碳酸钙对Zn均有较强的络合吸附效应,能有效降低Zn的迁移活性,从而促进吸附,抑制解吸. 相似文献
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水稻对不同土壤中硒酸盐/亚硒酸盐的吸收和富集 总被引:8,自引:1,他引:7
通过土培试验研究了在3种类型土壤(红壤、黑土和灰钙土)上施用不同价态硒肥(Na2 SeO3或Na2 SeO4)条件下,水稻地上部硒含量的变化.结果表明,在水稻幼苗期,3种土壤上Se4+硒肥处理的水稻幼苗地上部硒含量高于Se6+硒肥处理.施用Se4+硒肥,红壤、黑土及灰钙土中水稻幼苗的硒含量分别为5.76、1.18和1.11 mg· kg-1,分别为对照的2.5、4.7和6.9倍;施用Se6+硒肥,红壤、黑土及灰钙土中水稻幼苗的硒含量分别为4.70、0.66和0.73 mg·kg-1.在水稻成熟期,施用Se4+硒肥后,红壤、黑土及灰钙土中水稻籽粒中硒含量分别由对照中的0.34、0.05和0.05 mg·kg-1增加到0.94、0.14和0.20 mg·kg-1;施用Se6+硒肥后,红壤、黑土及灰钙土中水稻籽粒中硒含量分别为1.13、0.12、0.16mg·kg-1.不同价态硒肥处理和土壤类型对水稻幼苗和成熟地上部硒含量都有显著影响.在pH值低的红壤上施用Se6+硒肥效果更好,而在pH值高的黑土和灰钙土上施用Se4+硒肥效果更好;从环境风险和硒对植物毒性的角度考虑,硒肥以亚硒酸盐的形式施用比较好. 相似文献
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青藏高原土壤有机碳密度垂直分布研究 总被引:16,自引:0,他引:16
通过对青藏高原土壤普查数据的整理分析,定量研究了青藏高原28个典型土壤类型、14个主要生态系统类型0~20cm、20~50em及50~100cm深度内土壤有机碳密度的垂直分布规律.结果表明,青藏高原28个典型土壤类型3个土层的有机碳密度平均值为(6.16±1.08)kg·m-2、(5.06 ±0.85)kg·m-2、(5.30±0.82)kg·m-2;在0~100cm土层内,暗棕壤、沼泽土的有机碳密度显著高于其它土壤类型,而高山漠土、灰棕漠土、亚高山漠土的有机碳密度不仅远远低于区域平均水平,而且显著低于其它土壤类型.14个典型生态系统土壤的有机碳密度均值为(7.47±1.38)kg·m-2、(6.07±1.24)kg·m-2、(6.46±1.16)kg·m-2;其中,以沼泽草甸、针叶林土壤的有机碳密度最高,而温性荒漠、高寒荒漠、高寒草原及亚高山草原土壤有机碳密度显著低于其它生态系统.这不仅体现了青藏高原土壤-植被显著的地带性分布,而且为青藏高原土壤有机碳循环模型,及有机碳对全球变化的响应研究提供重要的基础数据. 相似文献
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目前,工业锅炉仍广泛采用的薄壁钢管空气预热器由于烟气侧低温腐蚀和结灰堵塞,使烟道通风阻力增加,排烟温度升高,对锅炉的热效影响极大。而且使用寿命短,疏通困难,甚至威协锅炉运行安全。为此,防止和减轻空气预热器的腐蚀和堵灰,已成为众多企业研究的重要课题。 相似文献
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四川的紫色土在全国紫色土中占有极其重要的地位,而重庆的灰棕紫坭又是四川具有代表性的紫色土,因此研究重庆地区土壤中微量元素的背景含量及其分异规律,不仅为我市农业规划、环境容量研究、环境质量评价研究具有典型的意义,而且为全川土壤背景值的研究提供直接参考。为此,重庆市环境保护局组织了重庆环境科研监测所、西南农学院土化系、西南师范学院环境科研组共同组成科研协作组,经过一年零五个月的工作,完成了重庆地区土壤中11种元素背景值的研究,并取得了可喜成果。 相似文献
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Paul Ney 《Die Naturwissenschaften》1981,68(12):597-605
Types of asbestos are distinguished not only by structure, chemical compositon, shape of aggregates, and length and quality of fibers, but also by its formation. Though consisting of quite common elements, deposits are formed only under very special conditions. Its unique combination of properties has created over 3000 fields of application (about 70% in asbestos cement). Great efforts have been made to substitute all types of asbestos by harmless, similarly cheap and versatile synthetic fibers, owing to the unquestioned carcinogenic properties of all asbestos dusts. However, development of such fibers has not made any remarkable progress until recently. Consequently risk to workers in mining and manufactoring, consumers, outsiders, and the environment should be kept as low as possible by intensifying precautions and diminishing emissions. 相似文献
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This work was conducted to evaluate whether Ca-bearing additives used during coal combustion can also help with the retention of some other elements. This work was focused on the evaluation of bottom ashes collected during four full-scale combustion tests at an operating thermal fluidized-bed power station. Bottom ashes were preferred to fly ashes for the study to avoid interference from condensation processes usually occurring in the post-combustion zone. This work focused on the behaviors of S, Cl, Br, As, Mn, V, Cr, Ni, Cu,Zn, W, and Pb. Strong positive correlations with CaO content in bottom ashes were observed(for all four combustion tests) for S, As, Cl and Br(R = 0.917-0.999). Strong inverse proportionality was calculated between the contents of Pb, Zn, Ni, Cr and Mn and CaO, so these elements showed association to materials other than Ca-bearing compounds(e.g., to aluminosilicates, organic matter, etc.). Somewhat unclear behaviors were observed for W, Cu, and V. Their correlation coefficients were evaluated as statistically "not significant", i.e., these elements were not thought to be significantly associated with CaO. It was also discovered that major enrichment of CaO in the finest bottom ash fractions could be advantageously used for simple separation of elements strongly associated with these fractions, mainly S and As, but also Cl or Br. Removal of5% of the finest ash particles brings about a decrease in As concentration down to 77%-80% of its original bulk ash content, which can be conveniently used e.g., when high As content complicates further ash utilization. 相似文献
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珊瑚钨锡矿硅质尾矿中Cd、As、Zn、F富集迁移及环境污染 总被引:1,自引:0,他引:1
硅质尾矿在释放中性矿山废水(NMD)时所伴生的多元素复合污染问题值得重视。本文以桂东北珊瑚矿尾矿作为研究对象,通过分析该尾矿的组构、元素富集及迁移特性,筛选出主要污染元素,并探讨尾矿胶结层对元素富集迁移的影响。结果表明:(1)该尾矿中Cd、As、Zn及F富集程度较高、可交换态含量(易迁移释放量)较大,是主要的污染元素,而Cu、Pb、Tl产生污染的可能性较小;(2)胶结层对重金属具有再富集作用,但其对可交换态Cd、As(Tl)再富集明显,而对可交换态Cu、Pb、Zn再富集则不明显。胶结层中次生伊利石、石膏等胶结物趋向于吸附富集活性可交换态Cd、As。这表明该尾矿可能迁移释放出含Cd、As浓度较高的NMD。研究表明,硅质尾矿风化释出NMD的同时,可能伴生Cd、As、Zn等重金属以及F的复合污染。 相似文献
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Kurunthachalam Kannan Simonetta Corsoline Takashi Imagaws Silvano Focardi John P.Giesy 《Ambio-人类环境杂志》2002,31(3):207-211
我们曾对从意大利收集的金枪鱼、箭鱼、普通鸬鹚以及家燕体内的p,p'-DDE、多氯联苯同类物(PCBs)、多氯二苯-p-二恶英(PCDDs)、多氯二苯并呋喃(PCDFs)以及多氯萘(PCNs)浓度进行过测量. 相似文献
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Vine Edward L. Sathaye Jayant A. 《Mitigation and Adaptation Strategies for Global Change》2000,5(2):189-216
In this paper, we present an overview of guidelinesdeveloped for the monitoring, evaluation, reporting,verification, and certification (MERVC) ofenergy-efficiency projects for climate changemitigation. The monitoring and evaluation ofenergy-efficiency projects is needed to determine moreaccurately their impact on greenhouse gas (GHG)emissions and other attributes, and to ensure that theglobal climate is protected and that countryobligations are met. Reporting, verification andcertification will be needed for addressing therequirements of the Kyoto Protocol. While the cost ofmonitoring and evaluation of energy-efficiencyprojects is expected to be about 5–10% of a project'sbudget, the actual cost of monitoring and evaluationwill vary depending on many factors, including thelevel of precision required for measuring energy andGHG reductions, type of project, and amount of fundingavailable. 相似文献
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《Journal of Cleaner Production》2006,14(17):1557-1558
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