Bioavailability of heavy metals in urban particles     

Xidan FENG Yan LIU Zhi DANG Weilin HUANG 《中国地球化学学报》2006,25(B08):224-224

Urban particles, as one of the toxic air pollutants, are important issues concerning air quality and public health, especially in large cities like Guangzhou （China）. Toxicological studies implicated heavy metals （particularly water-soluble metals） as a health hazard of particles. Once absorbed into human lung tissues, heavy metals are likely released from the particles and do harm to human body even in low concentrations. Thus, evaluating the bioavailability of heavy metals in urban particles is quite necessary. The particle samples used in this study were collected from a building roof in Guangzhou. Three different methods, sequential extraction procedure and two leaching tests, were employed to investigate the bioavailability of heavy metals in the particles. The sequential extraction scheme is specific for analyzing the chemical speciation of metals in particles, which consists of four fractions： F1： soluble and exchangeable metals; F2： carbonates, oxides and reducible metals; F3： bound to organic matter, oxidisable and sulphidic metals; and F4： residual metals. Leaching tests, GB 5086.2-1997 and TCLP, are standard methods developed by China-EPA and US-EPA and widely used in evaluating the toxicity of solid wastes. They were applied to gain additional information about more easily mobilized form of metal. Heavy metals in extraction solution, including Cu, Zn, Pb, Cd, Cr, and Ni, were analyzed by ICP-MS. According to the data from the total concentration analysis, the relative contents of 6 heavy metals in particles follow the order of Pb〉Zn〉Cu〉Cr〉Ni〉Cd. The results of sequential extraction showed that more than 50% of Cu, Zn and Cd were distributed in the F1, F2, and F3. This indicated that the bioavailability of Cu, Zn and Cd in the particles is much higher than that of Pb, Cr, and Ni. Leaching tests revealed that the concentrations of heavy metals in leachate are relatively lower than the regulatory level. The results of TCLP are much higher than those of GB 5086.2-1997, mainly due to the low pH value of the extraction fluid.  相似文献   

土壤和沉积物中元素的化学形态及其顺序提取法   总被引：53，自引：0，他引：53  

王亚平  黄毅  王苏明  许春雪  刘妹 《地质通报》2005,24(8):728-734

介绍了形态分析的概念和化学形态分析方法，探讨了广泛应用于土壤、沉积物重金属形态分析中的Tessier和BCR顺序提取方案及其异同，综述了顺序提取方法在地球化学、环境科学、农业科学等方面的应用及中国相关标准物质的研制现状。  相似文献   

Arsenic Geochemistry of the Great Dismal Swamp,Virginia, USA: Possible Organic Matter Controls   总被引：1，自引：0，他引：1  

Shama E. Haque  Jianwu Tang  William J. Bounds  David J. Burdige  Karen H. Johannesson 《Aquatic Geochemistry》2007,13(4):289-308

Surface water samples for arsenic (As) concentration and speciation analysis were collected from organic matter-rich blackwaters of the Lake Drummond portion of the Great Dismal Swamp in southeastern Virginia, USA. Arsenic concentrations and speciation were determined by selective hydride generation, gas chromatography with photoionization detection. Surface waters from the Great Dismal Swamp are high in dissolved organic carbon (DOC) concentrations (445–9,600 μmol/kg) and of low pH (4.2–6.4). Total dissolved As concentrations [i.e., As(III) + As(V)], hereafter As_T, range from 2.2 nmol/kg to 21.4 nmol/kg. Arsenite, As(III), concentrations range from ∼1 nmol/kg to 17.7 nmol/kg, and As(V) ranges from ∼1 nmol/kg to 14.1 nmol/kg. Arsenate, As(V), is the predominant form of dissolved As in the inflow waters to the Great Dismal Swamp, whereas within the swamp proper arsenite, As(III), dominates. Arsenite accounts for 8–37% of As_T in inflow waters west of the Suffolk Scarp, and between 54% and 81% of As_T in Lake Drummond and Great Dismal Swamp waters east of the scarp. Arsenite is strongly correlated to DOC (r = 0.94) and inversely related to pH (r = −0.9), both at greater than the 99% confidence level. Arsenate is weakly related to pH and DOC (r = 0.4 and −0.37, respectively), and neither relationship is statistically significant. No statistical relationships exist between As(V) or As(III) and PO₄ concentrations. The predominance of As(III) and its strong correlation with DOC in Great Dismal Swamp waters suggest that DOC may inhibit As(III) adsorption or form stable aqueous complexes with As(III) in these waters. Alternatively, phytoplankton and/or bacterially mediated reduction of As(V) may be important processes in the organic-rich blackwaters and/or sediment porewaters of the swamp, leading to the prevalence of As(III) in the water column.  相似文献   

茜素红S-微分吸附计时电位法测定土壤中铝形态     

干宁  李天华陈妮童爽  徐伟民 《岩矿测试》2007,26(3):193-197

报道了茜素红S-微分吸附计时电位法分别在酸性和碱性条件下直接检测土壤浸提液中的无机单核铝[Ali]和总单核铝[Ala]浓度，并用该法测定了酸消化浸提液中的总铝[AlT]，由[Ala]-[Ali]间接得到有机单核铝[Alo]，[AlT]-[Ala]得到酸溶态铝[Alr]，从而实现了土壤浸提液中5种铝形态的电化学测定。应用此方法测定了多个实际土壤样品，与标准Driscoll法进行了对照．结果基本一致。  相似文献   

Field Experimental Investigations on the Fe(II)- and Fe(III)-Content in Cloudwater Samples     

F. Deutsch  P. Hoffmann  H. M. Ortner 《Journal of Atmospheric Chemistry》2001,40(1):87-105

The Fe(II)/Fe(III)-partition in cloudwater samples collected during two field campaigns is evaluated. It turned out that the simultaneous occurrence of complexing and reducing substances in the atmosphere and the cloud processing increase the solubility of iron compounds present in aerosol particles. A correlation between the concentration of iron(II) in the liquid phase and the intensity of the solar irradiation was observed for most of the cloudwater samples. This could be due to the fact that both the photochemical reduction of the iron(III) complexes and the photochemical reductive dissolution of iron(III)(hydr)oxides are depending on the pH-value. Iron(II) seems to be oxidised back to iron(III) preferably by hydrogen peroxide during the night. Positive correlations were received e.g. between the concentration of dissolved iron and the concentration of oxalate and between the percentage of iron(III) and the concentration of hydrogen peroxide. A negative correlation was found e.g. between the concentration of dissolved iron and the pH-value. The uncertainty of the whole process of sampling and analysis was investigated and the conformity of the results was satisfying considering the sometimes difficult conditions during a field campaign.  相似文献   

氢化物发生原子荧光光谱法测定土壤中络合态锑   总被引：5，自引：0，他引：5  

梅俊  熊采华等 《岩矿测试》2002,21(4):275-278

采用酒石酸作提取剂，氢化物发生原子荧光光谱法测定土壤中络合态Sb(Ⅲ）和Sb(Ⅴ）。研究了氢化物发生原子荧光光谱测定土壤中络合态Sb(Ⅲ）和Sb(Ⅴ）的浸提和还原条件及对测定结果的影响。Sb(Ⅲ）和总Sb检出限分别为0.11μg/L和0.09μg/L。相对标准偏差（RSD，n=11)分别为5.4%和6.1%，加标回收率在82.5%-101.9%。  相似文献   

Thermodynamic modelling of C–O–H fluids     

Jan-Marten Huizenga 《Lithos》2001,55(1-4):101-114

H₂O, CO₂, CH₄, CO, H₂ and O₂ are the most important species in crustal fluids. The composition of these C–O–H fluids can be calculated if the pressure, temperature, carbon activity, and either the oxygen fugacity or the atomic H/O ratio of the fluid is known. The calculation methods are discussed and calculation results are illustrated with isobaric T–X_i, P–T, and isobaric–isothermal ternary C–O–H diagrams. Fluid inclusion compositions, in particular, the X_CO2/(X_CO2+X_CH4) ratio, can be used for C–O–H model calculations. However, care should be taken about possible post-entrapment changes, which may have modified the chemical composition of the fluid inclusion.  相似文献   

Identification of Anomalous Aluminium Contents in Surface and Ground Water in the Alba Territory (NW Italy)     

Massimo Civita  Adriano Fiorucci  Roberta Miè 《Geostandards and Geoanalytical Research》2001,25(2-3):431-439

Aluminium was determined in surface and ground waters in the Alba region of NW Italy to provide information on natural and anthropogenic sources of contamination. Determinations were made by a spectrophotometric method based on the aluminium-pyrocatechol complex. The total aluminium content of waters was determined as well as the toxic form of monomeric aluminium, obtained from samples that had been passed through 0.20 μm cellulose filters to remove colloidal and particulate material. Results were correlated with mortality data associated with Alzheimer's disease. There appeared to be a correlation between mortality data and areas having the highest aluminium content of water.  相似文献   

白垩-第三纪界线样品异常铱的赋存状态及其地质意义   总被引：1，自引：0，他引：1       下载免费PDF全文

孔屏  柴之芳 《地质科学》1993,(1):87

 通过对地质样品中铱的赋存状态研究及对残渣相中微粒的透射电镜分析,得出:在K-T界线样品中铱主要存在于残渣相中,不利于地球化学过程富集铱;铱在残渣相的富集与有机不溶物的存在没有必然联系;白垩-第三纪的生物绝灭事件中有火山活动参与;K-T界线事件的触发物为地外物质撞击。最后提出了K-T界线样品异常铱来源于地外物质撞击和火山喷发的混合模型。  相似文献   

Mineralogical speciation of elements in an eastern Canadian feed coal and their combustion residues from a Canadian power plant     

P. K. Mukhopadhyay  G. Lajeunesse  A. L. Crandlemire 《International Journal of Coal Geology》1996,32(1-4)

Systematic changes in mineralogy, enrichment and depletion of selected elements, and mineralogical speciation of selected elements in fly ash and bottom ash samples from the Lingan Power Plant were compared to run-of-mine and pulverized feed coal from the Sydney coalfield, Nova Scotia, eastern Canada. The analytical techniques used were an electron microprobe equipped with energy and wavelength X-ray dispersive spectrometers, X-ray diffraction, neutron activation, scanning electron microscopy with energy dispersive X-ray and incident light petrography. Three types of glasses (Fe/O-rich, Fe/Al/Si/O-rich and or Al/Si/O-rich) were identified in the combustion residues; they were formed as a result of the interaction of melted pyrite and clay minerals. Compared to the feed coal, most elements were enriched 10 to20 times in the fly ash. The concentration of the elements in both the fly ash and bottom ash are comparable to coal ash that is generated by the low temperature asher in the laboratory. Some chalcophile elements such as arsenic and lead occurred as a solid solution in pyrite in the feed coal and were concentrated in the float fraction (density: <2.81 g/cm³) of the fly ash with non-crystalline Fe-oxides. X-ray mapping of arsenic in the fly ash and bottom ash indicates that arsenic was evenly distributed as oxide within the Fe/O- and Fe/Al/Si/O-rich glass and crystalline phases in the fly ash, possibly in solid solution. Arsenic is associated with Fe/O and Fe/S crystalline phases in the bottom ash.  相似文献