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1.
为摸清成都平原土壤-水果系统中重金属污染水平和富集特征,通过对成都平原典型地区333个水果作物及其根部表层土壤中Hg、As、Pb、Cd、Cu、Cr和土壤理化指标的测定,结果表明:(1)研究区土壤养分整体呈现出有效磷和碱解氮较丰富,有机质和速效钾较缺乏的特征,可通过增施有机肥、地面覆草、施用绿肥等方式提升土壤肥力水平。(2)研究区土壤重金属存在部分点位超标,以Cd的超标率最高。土壤重金属单因子评价污染等级为清洁,土壤综合污染指数评价污染等级为中度污染,其主要贡献为Cd。研究区重金属存在一定程度的富集,Cd和Hg的污染指数高,潜在生态风险强,应重点关注土壤Cd污染和Hg含量水平的增加趋势,将Cd污染作为下一步土壤风险管控和修复治理的重点目标。(3)研究区水果Pb、Cd的超标率分别为5.7%、7.8%,不同水果Pb、Cd的超标率差异显著,草莓Cd的超标率最高。研究区水果中重金属未对成人构成非致癌健康风险,而水果中的As和Cu对儿童构成了非致癌健康风险,As和Cu对水果重金属非致癌总指数的贡献超过70%,应特别关注水果中As和Cu的管控,以免造成较大的食源性危害。(4)重金属在水果与土壤中的含量水平关联性较低,水果中重金属的含量与水果富集重金属的能力关联度极高,应进一步查明水果重金属与土壤重金属形态的关系,并结合调整水果种植结构、筛选重金属低积累水果品种等方式降低水果重金属的健康风险。  相似文献   
2.
成都市土壤-植物系统铅污染状况初步研究   总被引:6,自引:1,他引:6  
为研究成都市土壤-植物系统铅污染状况,分析了成都市五种蔬菜及其根系土的铅含量。结果表明,土壤铅含量变化范围61.0~115.0mg/kg,均值为77.3mg/kg,所有样品含量均超过成都市土壤环境背景值,以城东和城南污染最为严重;蔬菜中铅含量以莴笋叶最高,萝卜最低,叶菜类高于瓜果类;蔬菜污染严重区与土壤污染区差别明显,说明土壤铅和植物铅污染源不同。  相似文献   
3.
应用地质累积指数评价成都市河流表层沉积物重金属污染   总被引:10,自引:0,他引:10  
根据流经成都市内的三条河流(府河、南河、沙河)表层沉积物重金属资料,应用地质累积指数法对重金属污染进行了评价研究。结果表明,河流主要的重金属污染物是Cr,地质累积指数分级多在0~1之间,属于无污染-中度污染范畴。  相似文献   
4.
The acidic gases such as SO2, NOx, H2S and CO2 are typical harmful pollutants and greenhouse gases in the atmosphere, which are also the main sources of PM2.5. The most widely used method of treating these gas molecules is to capture them with different adsorption materials, i.e., metal and nonmetallic materials such as MnO2, MoS2 and carbon-based materials. And doping transition metal atoms in adsorption materials are beneficial to the gas adsorption process. The first-principles calculation is a powerful tool for studying the adsorption properties of contaminant molecules on different materials at the molecular and atomic levels to understand surface adsorption reactions, adsorption reactivity, and structure-activity relationships which can provide theoretical guidance for laboratory researches and industrial applications. This review introduces the adsorption models and surface properties of these gas molecules on metal and nonmetallic surfaces by first-principles calculation in recent years. The purpose of this review is to provide the theoretical guidance for experimental research and industrial application, and to inspire scientists to benefit from first-principles calculation for applying similar methods in future work.  相似文献   
5.
The influence factors of surfactant-type catalysts system on the asymmetric transfer hydrogenation (ATH) of ketones in water, including the length of aliphatic tail, the concentration of catalysts and the solvent, have been investigated. These factors played significant roles on reaction activity and stereo control. With single-chain surfactant-type catalyst Rh-L4, α, β-unsaturated ketones especially the aliphatic derivatives affords excellent regioselectivities and enantioselectivities.  相似文献   
6.
A simple, efficient, and economical synthetic approach to construct a variety of stucturally novel indolizines bearing a phenolic hydroxy group has been developed through 1,3-dipolar cycloaddition of chromones and pyridinium salts. The methodology is tolerant of a wide range of functional groups and applicable to library synthesis.  相似文献   
7.
Acetohydroxyacid synthase(AHAS) was considered as a promising target for antifungal agents.Herein,three series of novel sulfonylureas(SUs) 9-11 containing aromatic-substituted pyrimidines were designed and synthesized according to pharmacophore-combination and bioisosterism strategy.The in vitro fungicidal activities against ten phytopathogenic fungi indicated that most of the title compounds exhibited broad-spectrum and excellent fungicidal activities.Based on the preliminary fungicidal activities,a CoMFA model was constructed and the 3 D-QSAR analysis indicated that either a bulky group around the 5-position of the pyrimidine ring or electropositive group around the 2-position of the benzene ring would be favour to fungicidal activities.In order to study interaction mechanism,10 k was automatically docked into yeast AHAS and it further indicated that bearing bulky groups-aryl at the pyrimidine ring was critical to enhance antifungal activities.It revealed that the antifungal activity of derivatives 9-11 probably results from the inhibition of fungal AHAS.Thus,the present results strongly showed that SUs should be considered as lead compounds or model molecules to develop novel antiphyt o pathogenic fungal agents.  相似文献   
8.
通过野外定点采集土壤和作物植株、籽粒样品, 利用石墨炉(novAA400)原子吸收法, 研究了成都平原稻麦轮作下水稻土剖面中镉的分布特征及其与水稻、小麦吸收镉的相关性。结果表明,土壤剖面中的镉主要集中在0~15 cm的耕层土壤,总体表现为“向根层富集”的特征,土壤全镉和有效态镉均随土层深度的增加而逐渐降低,30~45 cm土层的全镉和有效态镉含量平均值分别为表层的47.60%和39.49%。不同质地土壤中的镉向下迁移量大小顺序为砂壤>重壤>中壤,以15~30 cm土层的迁移量差异最大。土壤pH与0~15 cm土层的有效态镉含量间相关性不显著(r=-0.46),与15~30 cm和30~45 cm土层有效态镉含量间呈显著的负相关(r=-0.78*~-0.86**)。水稻、小麦秸秆和籽粒镉含量与0~15 cm和30~45 cm土层的全镉含量间相关性不大(r=-0.092~-0.383, 0.174~0.424),但与0~15 cm和15~30 cm土层的有效态镉含量呈显著正相关(r=0.766*~0.953**),与30~45 cm土层的有效态镉含量相关性不显著(r=0.526~0.584)。因此,土壤有效态镉含量比全镉含量更适合作为农作物产品安全的土壤镉污染评价指标。  相似文献   
9.
成都地区太阳紫外UV-B辐射的测量与分析   总被引:2,自引:1,他引:2  
本文报道成都地区紫外UV-B辐射的系统测量与分析。成都地区地面紫外UV-B辐射存在明显的日变化、月变化、月际变化特征:晴天紫外UV-B辐射早晚小,中午大,日最大值为3.65 W/m2,日最小值为0.4167 W/m2;UV-B辐射月最大值为3.67 W/m2,最小值为1.67 W/m2,月变化达1.7 W/m2;2006年7月正午紫外UV-B辐射比2005年12月高出3.63 W/m2。夏季晴天正午地面UV-B辐射最大值为3.93W/m2,远小于中国其他城市的辐射量。而成都位于四川盆地,以多云多雾天气为特征,不同云雾量对紫外辐射有不同程度的衰减,因此成都地区地面实际的紫外辐射相对较弱。  相似文献   
10.
《天然气化学杂志》2014,(5):I0001-I0002
  相似文献   
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