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831.
杭州市郊蔬菜基地土壤和蔬菜中Pb、Zn和Cu含量的环境质量评价 总被引:46,自引:5,他引:41
对杭州市4个蔬菜基地土壤中Pb、Zn、Cu进行测定分析,利用不同的评价方法和标准来评价土壤重金属的环境质量状况,并在GIS软件平台下,通过克里格插值法分析了江干区蔬菜基地土壤-蔬菜重金属含量空间分布特征.结果发现蔬菜基地土壤中重金属含量超过自然背景值,未超过以国家土壤重金属环境质量标准,是符合无公害蔬菜基地的要求的;4个调查区中拱墅区土壤中重金属含量大于其它3区;江干区蔬菜基地土壤-蔬菜中重金属的空间变异很大;小白菜/小青菜中Zn和Cu的含量未超标,Pb则超标;2种蔬菜的富集系数均是Zn>Pb>Cu,小青菜Pb、Zn、Cu的富集系数和含量均大于小白菜,更易受到土壤中重金属的影响. 相似文献
832.
Zhao B Maeda M Zhang J Zhu A Ozaki Y 《Environmental science and pollution research international》2006,13(2):90-97
Goal, Scope and Background Andisols are widespread in Japan and have some special properties such as high anion exchange capacity, low bulk density,
and high organic matter content, which might influence the accumulation or chemical fractionation of heavy metals. However,
few such data exist in Japanese andisols. The primary objective of this study was to investigate the distribution and chemical
fractions of Cu, Zn, Ni, and Cr in the soil profiles and subsequently to assess their potential environmental hazard.
Materials and Methods Soil samples were taken from a field experiment conducted on Japanese andisols, which had received either swine compost or
chemical fertilizers for 6 years. Concentrations of Cu, Zn, Ni, and Cr were determined for all of the obtained extract solutions
by ICP-AES.
Results and Discussion Considerably higher total concentrations of Cu and Zn were observed in the top 20 cm layer of the compost-amended soil, relative
to the unfertilized soil, while chemical fertilizers had little effect. Application of the swine compost increased the concentrations
of Cu and Zn, but not Ni and Cr, in all fractions in the top 20 cm layer. The greatest increase in the organically bound fraction
(OM) Cu and dilute acid-exchangeable fraction (DAEXCH) Zn was observed. This suggests that Cu and Zn are potentially bioavailable
and mobile in the andisol profiles after 6-year consecutive applications of the swine compost. On the other hand, distribution
of Cu, Zn, Ni and Cr among various soil fractions was generally unaffected by chemical fertilizers.
Conclusions We observed that 6-year consecutive applications of the swine compost led to an increase in total metals of Cu and Zn, as
well as their all-chemical fractions, in the top 20 cm soil layers. Potential hazard of heavy metals, especially of Cu and
Zn, as a result of the use of swine compost on andisols, must be taken into account.
Recommendations and Outlook The long-term effect of the accumulation of heavy metals, particularly Cu and Zn, in various plant tissues and soils, as
well as their potential risk to surface water via runoff and groundwater via leaching, needs to be carefully considered. Further
investigations in the long-term experiments are therefore necessary.
- Abbreviations. EXCH, exchangeable fraction of metals; DAEXCH, dilute acid-exchangeable fraction of metals; FeMnOX, iron and
manganese-oxide-bound fraction; OM, organically-bound fraction; RESD, residual fraction. COMPOST, SRNF, RANF, and CONTROL
stand for compost (from swine wastes), slow-release nitrogen fertilizer (coated urea), readily available nitrogen fertilizer
(including NH4-N, P, and K fertilizers), and no fertilizer application, respectively. 相似文献
833.
834.
Bingdi Liu Lin Zhang Jason H. Knouft Fangqiong Ling 《Frontiers of Environmental Science & Engineering》2022,16(5):64
835.
在2个相同的USB反应器(R1无载体,R2采用多孔生物填料为载体)中构建了短程反硝化工艺,对R1和R2NO3--N→NO2--N转化性能、短程反硝化颗粒污泥物化特性、胞外聚合物(EPS)产生特性以及微生物功能菌群主要特征进行差异分析.结果表明,反应器运行81d,氮负荷(NLR)为1.2kg/(m3·d)时,NO3--N→NO2--N转化率(NTR) R2(85%)高于R1(80%);载体颗粒污泥(R2)沉降性能优于自固定化颗粒污泥(R1)且载体颗粒污泥(R2)更容易截留EPS,PN/PS值R1(1.29)>R2(1.15),污泥体积指数(SVI) R1(27.07mL/g MLSS)>R2(19.36mL/g MLSS);扫描电镜发现R1污泥表面聚集长杆菌,R2污泥表面聚集短杆菌和球菌,与R1相比R2颗粒污泥结构更加规则密实.微生物高通量测序结果表明,R2物种丰富度和多样性高于R1,变形菌门、拟杆菌门和绿弯菌门在短程反硝化系统中占主导地位,R1和R2主要NO2--N积累功能菌属均为Acinetobacter属(R1-59.18%、R2-46.04%)和Thauera属(R1-6.81%、R2-5.99%). 相似文献
836.
锌(Zn)既是生物体必需元素又是有害元素,在复合污染的情况下,Zn在植物吸收、转运和富集镉的过程中发挥着重要作用。以往研究主要关注镉的活性,忽略了Zn的环境活性。基于此,本研究以黑色岩系地质高背景区自然富Zn土壤为对象,重点研究了土壤Zn的活性态和潜在活性态,讨论了Zn活性的影响因素和环境意义。结果表明,研究区土壤Zn富集,平均含量可达457 mg/kg,80%的土壤样品超过我国农用地土壤污染风险筛选值。CaCl2提取态Zn含量平均值为0.92 mg/kg,平均提取率仅为0.26%,说明研究区土壤Zn的生物活性低,且随着pH升高而降低。EDTA提取态Zn的平均含量为12.7 mg/kg,平均提取率为2.74%,潜在有效态比例也较低。活性态在潜在活性态中占比为7.63%,活化潜力较大,且随着土壤pH的升高而降低。研究区土壤溶液中Zn∶Cd比较低,可能有利于植物对镉的吸收。开展土壤Zn活性的研究,对理解复合污染区土壤镉的活性变化及调控具有重要意义。 相似文献