大同盆地浅层含水层沉积物中砷的生物可利用性评价     

欧阳光明  谢作明  孙小燕  杨东  王焰新 《现代地质》2015,29(2):260-264

以采自大同盆地野外试验场的含水层沉积物为研究对象,调查高砷含水层中生物可利用性砷的含量及其影响因素。经实验室测定,沉积物总体呈碱性,Al、Fe等金属元素含量较高。利用连续提取法发现沉积物中砷结合形态主要为无定形和低结晶铁铝氧化物结合态,其次是残余态砷。其中铁铝氧化物形态的砷所占比例达53.54%,非专性吸附态和专性吸附态占14.33%,生物可利用形态的砷较少,这与体外模拟方法测定的生物可利用性砷含量较低吻合。体外模拟实验还发现：肠阶段生物可利用性砷含量比胃阶段低,生理学提取法(PBET)和体外消化法(IVG)测定的生物可利用性砷差异较小。  相似文献   

云南兰坪金顶铅锌矿区土壤中Pb分布特征   总被引：8，自引：0，他引：8  

李瑞萍  王安建  曹殿华  耿诺  高兰  邹为雷  赵以辛  修群业 《地球学报》2009,30(1):72-78

采用连续提取法测定兰坪金顶铅锌矿区土壤中Pb的形态含量,通过地统计方法分析污染物的空间分布、化学形态变化特征,结果表明金顶矿区土壤中Pb大范围严重超标,按照国家土壤环境质量标准(Ⅲ级),Pb的中位值超标1.77倍,平均值超标约19倍。插值分布图显示Pb的污染及形态分布受矿体空间展布、地形变化、矿业活动、地表径流等的影响,其中水溶态Pb受植被和水系影响更大。土壤中Pb形态含量依次为残渣态>碳酸盐态>活性铁锰态>有机结合态>离子交换态>水溶态,环境有效态(水溶态、离子交换态与碳酸盐态之和)含量比较高,对兰坪矿区及沘江流域具有潜在的巨大危害  相似文献   

HPLC-ICP-MS法研究内蒙古锡盟和新疆塔城高碘地区地下水的总碘及碘形态特征   总被引：1，自引：1，他引：0  

陈俊良  杨红霞  刘崴  刘景涛 《岩矿测试》2017,36(6):614-623

长期饮用高碘水将对人体造成危害,地下水总碘及碘形态分析对于高碘地区碘环境地球化学研究具有重要价值。本文采用高效液相色谱-电感耦合等离子体质谱联用技术对内蒙古锡盟与新疆塔城高碘地区地下水总碘及碘形态进行测定。研究表明:锡盟地区地下水中碘以I-形态为主,总碘量维持在200μg/L,个别点位达到600μg/L甚至1700μg/L,呈环状分布,从东北至西南呈现"低-高-低"的分布规律;塔城地区地下水中的碘以IO-3形态为主,总碘量不足100μg/L,个别点位接近200μg/L,呈层状分布,自东向西逐渐升高。分析认为,氧化性的条件利于不同碘形态之间的转化;溶解氧过高或过低都不利于碘的储存;碘会随着可溶性盐的流失而流失;沿河流的流向,下游地势较低,总碘得到积累。本研究结果对于锡盟和塔城地区科学预防甲状腺肿、制定法律法规具有指导作用。  相似文献   

Iron Speciation in Precipitation in the North-Eastern Mediterranean and Its Relationship with Sahara Dust     

Türkan Özsoy  A. Cemal Saydam 《Journal of Atmospheric Chemistry》2001,40(1):41-76

Precipitation samples collected at Erdemli, Turkey, during February 1996–June 1997 were analysed to determine iron content and speciation. The purpose of the measurements was to examine the atmospheric abundance of iron and to quantify its solubility in the region. Spectrophotometric analyses of Fe(II) and reducible Fe(III) in precipitation samples, along with measurements of pH, conductivity, filterable iron (Fe_filt), particulate aluminium (Al_par) and particulateiron (Fe_par) were performed to determine iron solubility, which principally affects its bioavailability. Backward trajectories corresponding to the sampling dates were analysed to determine the sources of atmospheric constituents arriving at the site. Among these, the mineral dust transported from the Great Sahara to the region is considered to be a rich source of iron. The concentration of Fe(II) varied from below detection limit (0.02 M) up to 0.42 M,while the maximum concentration of total reactive Fe (referred as Fe(II) + reducible Fe(III) = Fe_reac) was found to be 1.0 M in precipitation. A strong correlation was found between particulate Fe and Al fractions, both of crustal origin. No correlation was observed between the soluble and insoluble fractions of iron. The soluble iron fraction, Fe(II) concentration varied independently from the concentrations of reducible Fe(III), Fe_filt, Fe_par, and from the pH of the precipitation. The Fe_filt fraction (size < 0.45 m), measuredby Atomic Absorption Spectrophotometer, and frequently interpreted to be the soluble iron fraction in the literature, was found to be significantly higher than the corresponding Fe_reac fraction inprecipitation samples, most likely due to the colloidal iron content of the Fe_filt fraction passing through the 0.45 m pore size filter. The volume weighted mean Fe_filt concentration of the precipitation samples collected during the episodic `red rain' events was found to be relatively higher. The geometric mean ratios of soluble Fe(II) and of Fe_reac to Total Fe (Fe_filt + Fe_par), werefound to be 1.6% and 2.1%, respectively, while the mean ratioof Fe_filt to Total Fe was 9.6%. The flux of bioavailable iron (Fe_reac)fraction in most atmospheric wet deposition events was found to be sufficient for supporting the maximum primary production rates that are typical for the Eastern Mediterranean Sea.  相似文献   

Geochemical Processes Controlling the Formation of As-Rich Waters Within a Tailings Impoundment (Carnoulès, France)     

Corinne Casiot  Marc Leblanc  Odile Bruneel  Jean-Christian Personné  Kouadio Koffi  Françoise Elbaz-Poulichet 《Aquatic Geochemistry》2003,9(4):273-290

The distribution of arsenic (As(III), As(V)) and iron (Fe(II), Fe(III)) species was monitored during 1 year in a borehole drilled in the Carnoulès tailings impoundment which contains As-rich pyrite. The concentrations of total As and Fe in subsurface waters exhibited strong variations over one year, which were controlled by dissolved oxygen concentrations. At high oxygen levels, extremely high As (up to 162 mM) and Fe (up to 364 mM) concentrations were reached in the borehole, with the oxidised species predominant. As and Fe concentrations decreased 10-fold under oxygen-deficient conditions, as a result of pH increase and subsequent precipitation of As(V) and Fe(III). From drill core sections, it appeared that at low dissolved oxygen levels, As(III) was primarily released into water by the oxidation of As-rich pyrite in the unsaturated zone. Subsequent As and Fe precipitation was promoted during transport to the saturated zone; this reaction resulted in As enrichments in the sediment below the water table compared to the original content in pyrite, together with the formation of As-rich (up to 35 wt% As) ferruginous material in the unsaturated zone. High amounts of As(V) were released from these secondary phases during leaching experiments with oxygenated acid sulfate-rich waters; this process is believed to contribute to As(V) enrichment in the subsurface waters of the Carnoulès tailings during periods of high dissolved oxygen level.  相似文献   

Beryllium Geochemistry in the Lesni Potok Catchment (Czech Republic), 7 Years of Systematic Study     

T. Navrátil  P. Skřivan  L. Minařík  A. ŽIgová 《Aquatic Geochemistry》2002,8(2):121-133

The biogeochemical study was carried out at the Lesni potok (LP)catchment, Central Bohemia, Czech Republic. The ecosystem was impacted by heavy acid depositionduring the industrial development in 1980–1990. The catchment is forested mostly by two tree species, Norwayspruce and European beech. The Be concentration in the granite bedrock is 12.6 mg kg^-1. Theplagioclase contains the highest Be concentrations out of the rock-forming minerals. Elevatedconcentration of Be (5.4 mu;g L^-1) in surface waters is a result of its mobilization from the soils(3.9 mg kg^-1) and weathered rock by acid precipitation. As the pH of the precipitation and consecutivelypH of the surface waters is increasing in the Czech Republic, the Be concentrations in the surface watersgradually decrease. Groundwater with high pH values contains lower concentrations of Be (0.17 g L^-1)than surface waters. The soils at prone area of the catchment are depleted in Be compared to thesoils in the riparian zones. The vegetation located on the prone area contains lower concentrations of theBe than vegetation at riparian zones. The monitoring of Be in the environment is important with respectto its possible harmful effects on aquatic biota and root systems of the plants.  相似文献   

微波辅助萃取技术在有机锡砷汞化合物形态分析中的应用   总被引：5，自引：0，他引：5       下载免费PDF全文

梁立娜胡敬田  江桂斌 《岩矿测试》2003,22(2):137-143150

文章总结了近10年来萃取技术在有机锡、有机砷和有机汞化合物形态分析中的应用，对各种萃取技术进行了比较，并指出微波辅助萃取技术具有快速、高效、试剂消耗少、基体干扰少的优点。  相似文献   

土壤中稀土元素地球化学研究进展   总被引：12，自引：1，他引：12  

朱维晃  杨元根  毕华  刘强 《矿物岩石地球化学通报》2003,22(3):259-264

综述了土壤中稀土元素含量、稀土赋存形态、稀土生物有效性、稀土在土壤环境中的分布规律、迁移方式及其影响因子。讨论了稀土微肥应用中应注意的问题以及由此带来的环境效应，并探讨了建立具有普遍适用性的稀土生物有效性方法学的途径等。  相似文献   

改进BCR法在分析水系沉积物样品铅形态中的应用     

任萍  汪明启 《物探与化探》2004,28(3):222-223,221

研究了超声波水浴提 BCR顺序提取法在铅形态分析中的应用,优化了水系沉积物样品铅的各分步提取时间。与传统的BCR法相比,改进BCR法所用的提取时间由原来的几十小时缩短为几十分钟。氢化物 原子荧光法测定样品中3种形态铅含量的统计结果显示,改进BCR法分析精度好,各形态铅的提取效率高,是一种快速、定量铅形态分析方法。  相似文献   

密云水库沉积物-水界面磷的地球化学作用   总被引：11，自引：4，他引：11  

刘晓端 徐清刘浏  武佃卫 《岩矿测试》2004,23(4):246-250

以密云水库为例，研究了水库沉积物中有机质的含量与有机磷的关系，表明表层沉积物中的总有机碳和有机磷的含量都明显高于底层，是由于一些以磷为营养素的富营养化指示藻类在水体中逐年增加，它们死亡后的残骸经分解-矿化后在底积物中累积的结果。沉积物和孔隙水中磷的剖面特征研究表明，表层沉积物和孔隙水中的磷都有明显上升的趋势，是由于沉积物的表层微生物和活性有机碎屑层比较丰富，有机质降解和含磷的有机化合物分解，使溶解性磷酸盐进入孔隙水。对沉积物磷形态、总有机碳及孔隙水中总磷对磷释放的影响进行了线性相关分析，结果表明上覆水中的磷主要来自沉积物的铁结合态磷、铝结合态磷、溶解态磷三种形态，孔隙水中总磷以及总有机碳含量对上覆水中总溶解磷浓度存在较大的影响，这些为研究水库沉积物作为水库内污染源对水质的影响提供了基础资料。  相似文献