电热板消解ICP-AES法测定农田土壤中的重金属

选用盐酸-硝酸-氢氟酸-高氯酸消解体系,用电热板对土壤样品进行消解处理,采用电感耦合等离子体发射光谱法(ICP-AES)对土壤样品中铜、铅、锌、铬、锰、镍进行定量分析。实验表明,样品中所测重金属含量均满足国家二级标准,结果准确可靠,重复性好。且该方法操作简单,进样量少,定量迅速,准确度高,可同时检测多种元素,能够满足环境样品的分析。     

电感耦合等离子体发射光谱法测定土壤9种重金属元素

文章通过硝酸-氢氟酸-高氯酸电热板消解体系,采用电感耦合等离子体发射光谱测定土壤中Cd(镉)、Mn(锰)、Ni(镍)、Pb(铅) Zn(锌)、Mo(钼)、Ba(钡)、V(钒)、Co(钴) 9种重金属元素。结果表明,9种重金属元素RSD%范围在0.5%～6.2%之间,其中Pb、Zn、Mn、Ni、Ba、V 6种元素的加标回收率在79%～111%之间。镉和钼加标回收率小于70%。     

微波消解-电感耦合等离子体发射光谱法测定土壤中微量重金属

建立了微波消解-电感耦合等离子体发射光谱法测定土壤中微量重金属的样品前处理过程与方法,并通过仪器工作条件和酸消解体系的选择,以及光谱干扰和基体干扰的消除对方法进行了优化。结果表明,使用6m LHNO_3+2 m L HCl+1m LHF+1m LH_2O_2对土壤进行微波消解,在建立的试验条件下,土壤中重金属(铜、铅、锌、镉、锰、镍、铬和钒)的检出限为0.002~0.014 mg/kg,精密度为1.3%~3.6%,回收率为97.4%~106%。本方法简便、安全、准确、快速。     

微波消解-ICAP法测定土壤中总铬含量的研究

采用微波消解仪对土壤样品进行前处理,用ICAP测定土壤中总铬含量。通过硝酸-氢氟酸以及硝酸-盐酸-过氧化氢体系消解液对土壤样品消解,优化试验选择出微波最佳消解条件和ICAP的工作参数。结果表明,发现用硝酸-氢氟酸体系消解液,在谱线283.56 nm、267.72 nm处用ICAP能够准确而稳定地测得土壤中总铬含量。     

拟开发场地的土壤重金属污染调查与评价实践

土壤污染调查乃"土壤修复"的前期。在某市郊拟开发建设的场地,按8个点分三层采集了24个土壤样品,用原子吸收光谱法测定样品中汞、铅、镉、铜、锌、镍、铬等7种重金属元素的含量,汞呈现对数正态分布,其他元素为正态分布,各元素在土壤层水平分布状态和垂直分布水平的差异性不显著,锌含量水平现状值在《土壤环境质量标准》GB15618-1995二级标准的指标限值内,汞、铅、镉、铜、镍、铬含量水平现状值均在土壤环境质量一级标准的指标限值内,且各元素浓度水平现状值均与场地所在区域土壤背景值一致。由此,本调查的场地土壤环境现状没有受到铅、汞、镉、铜、锌、镍、铬金属元素污染。     

TOA-MIBK萃取火焰原子吸收法同时测定土壤及蔬菜中铅镉

用氢氟酸、硝酸、高氯酸消化土壤样品,干灰化法消解蔬菜样品,用相对TOA-MIBK系统萃取,火焰原子吸收光谱法在同一条件下测定土壤、蔬菜中的铅、镉。在选定条件下,测得土壤铅、镉的相对标准偏差分别为2．3％～4．4％和3．0％～4.3％,蔬菜铅、镉的相对标准偏差分别为2．9％～4．5％和2．6％～4．5％;土壤铅、镉的回收率分别为96％～104％和95％～101％,蔬菜铅、镉的回收率分别为93％～102％92％104％。由测定结果得出离公路越近,蔬菜、土壤铅、镉含量越高。     

石墨炉消解-电感耦合等离子体质谱法测定土壤中重金属

建立了石墨炉消解-电感耦合等离子体质谱法测定土壤中8种金属元素的分析方法,并通过仪器工作条件和消解条件的选择,以及质谱干扰和基体干扰的消除对方法进行了优化。结果表明,在建立的试验条件下对土壤进行石墨炉消解,土壤中重金属(锌、镍、铜、钒、铬、铅、镉、锰)的检出限为0.002~0.59μg/g,精密度为1.1%~8.7%,回收率为95.0%~105%。本方法消除干扰强,检出限低,精密度好,准确度高,试剂用量小,适用于大批量土壤样品的分析。     

连续光源石墨炉原子吸收法测定土壤中的镉

对连续光源石墨炉原子吸收测定土壤中的镉的实验条件进行优化,最终确定用盐酸-硝酸-氢氟酸-过氧化氢四酸法进行消解,选择0.1%的硝酸钯作为基体改进剂,灰化分两步进行,温度分别为300℃、450℃,保持时间分别为20 s、40 s,原子化温度为1 550℃,保持时间为3 s。研究表明,此方法测定土壤中的镉标准曲线的相关系数为0.999 9,方法检出限为0.006 mg/kg,相对标准偏差为5%～11%,加标回收率为85%～94%,对质控样的分析结果与标准值吻合。     

碘化钾——甲基异丁酮络合溶剂萃取火焰原子吸收法测定土壤中镉、铅等

在测定土壤中铜、铅、锌、镉、钴、镍等元素时,需要各种前处理,如(强酸消化、熔融法等),使待测成分完全释放出来以利测定,对于某些含量过低的元素如(镉、铅)还需要通过萃取富集。在前人工作的基础上,我们选择了王水—高氯酸、硝酸—双氧水消化土样;碘化钾—甲基异丁酮络合及二乙基二硫代甲酸钠—     

农村土壤环境质量监测与评价研究——以广东省某村庄为例

以广东某村庄为实例,介绍了农村土壤环境质量监测和评价方法。对该村庄菜地、基本农田、曾经污灌农田和怀疑受污染的农田土壤进行了12个样品砷、镉、钴、铬、铜、汞、镍、铅、硒、锌等元素全量和六六六、滴滴涕等有机氯农药含量监测,并分别采取单因子指数法和综合污染指数法分析了该村土壤污染状况。该村土壤中铜、镉、砷、硒、锌和铅超过GB 15618—1995二级标准和环保部《全国土壤污染状况评价技术规定》评价标准,主要以铜、镉和砷污染为主,其超标率分别为75.0%、58.3%和58.3%;重污染土壤样品数占总监测样品数的41.7%,受中度污染的土壤样品数占25.0%,受轻度污染土壤样品数占8.3%,处于警戒水平的土壤样品占25.0%。不同类型土壤污染程度各异,其中曾经污灌的土壤和怀疑受污染的土壤铜、镉、砷、锌、硒、铅含量较高,基本农田土壤次之,菜地最低。     

Fate of biosolids trace metals in a dryland wheat agroecosystem

Biosolids land application for beneficial reuse applies varying amounts of trace metals to soils. Measuring plant-available or total soil metals is typically performed to ensure environmental protection, but these techniques do not quantify which soil phases play important roles in terms of metal release or attenuation. This study assessed the distribution of Cd, Cr, Cu, Mo, Ni, Pb, and Zn associated with soluble/exchangeable, specifically adsorbed/carbonate-bound, amorphous Mn hydroxyoxide-bound, amorphous Fe hydroxyoxide-bound, organically complexed, and residual inorganic phases. Biosolids were applied every 2 yr from 1982 to 2002 (except in 1998) at rates of 0, 6.7, 13.4, 26.8, and 40.3 dry Mg biosolids ha(-)(1) to 3.6- by 17.1-m plots. In 2003, 0- to 20-cm and 20- to 60-cm soil depths were collected and subjected to 4 mol L(-1) HNO(3) digestion and sequential extraction. Trace metals were concentrated in the 0- to 20-cm depth, with no significant observable downward movement using 4 mol L(-1) HNO(3) or sequential extraction. The sequential extraction showed nearly all measurable Cd present in relatively mobile forms and Cr, Cu, Mo, Ni, Pb, and Zn present in more resistant phases. Biosolids application did not affect Cd or Cr fractionation but did increase relatively immobile Cu, Mo, and Zn phases and relatively mobile Cu, Ni, and Pb pools. The mobile phases have not contributed to significant downward metal movement. Long-term, repeated biosolids applications at rates considered several times greater than agronomic levels should not significantly contribute to downward metal transport and ground water contamination for soils under similar climatic conditions, agronomic practices, and histories.     

ICP-OES同时测定土壤中多种重金属可给态的研究

研究了以HNO3-HCl为提取剂、电感耦合等离子发射光谱法（ICP-OES）同时测定土壤中重金属As、Pb、Cr、Cu、Zn、Cd、Ni共7种元素的可给态的方法。实验结果表明,土壤中重金属可给态经HNO3-HCl提取后完全分解,采用内标法可以提高测定的准确度和精密度,该方法加标回收率为90.9%～106.3%,精密度〈3%,具有较好的准确度和精密度,是一种快速、高效的分析方法。     

Heavy metal content and distribution in surface sediments of the Seyhan River, Turkey

Chemical fractionation of seven heavy metals (Cd, Cr, Cu, Mn, Ni, Pb and Zn) was studied using a modified three-step sequential procedure to assess their impacts in the sediments of the Seyhan River, Turkey. Samples were collected from six representative stations in two campaigns in October 2009 and June 2010, which correspond to the wet and dry seasons, respectively. The total metal concentrations in the sediments demonstrated different distribution patterns at the various stations. Cadmium was the only metal that was below detection at all stations during both sampling periods. Metal fractionation showed that, except for Mn and Pb, the majority of metals were found in the residual fraction regardless of sampling time, indicating that these metals were strongly bound to the sediments. The potential mobility of the metals (non-residual fractions) is reflected in the following ranking: Pb > Mn > Zn > Cu > Ni > Cr in October 2009 and Mn > Pb > Zn > Cu > Ni > Cr in June 2010. The second highest proportion of metals was bound to organic matter/sulfides, originating primarily from anthropogenic activities. Non-residual metal fractions for all stations were highest in June 2010, which may be linked to higher organic matter concentrations in the sediment samples with 1.40% and 15.1% in October 2009 and June 2010, respectively. Potential sediment toxicity was evaluated using the Risk Assessment Code (RAC). Based on RAC classification, Cd and Cr pose no risk, Cu and Ni pose low risk, Pb and Zn were classified as medium risk metals, while the environmental risk from Mn was high. In addition, based on the sediment quality guidelines (SQG), the Seyhan River can be classified as a river with no, to moderate, toxicological risks, based on total metal concentrations.     

Trace elements in sediments in a city with agricultural development

The objective of this study was to determine the concentrations of trace elements in sediment samples taken from impermeable urban areas of a city with predominantly agroindustrial development characteristics. For this, samples were taken every month from paved streets in the city of Toledo, Paraná State (PR), Brazil. Thus, trace element levels were obtained through analysis performed by optical emission spectrometry with inductively coupled plasma. Levels of total organic carbon were also obtained through the dry combustion method. When compared to local background levels, the trace element levels were shown to be enriched in the following percentage proportions: barium (Ba) (45.4%), copper (Cu) (48.6%), chromium (Cr) (37.2%), manganese (Mn) (81.6%), nickel (Ni) (0%), lead (Pb) (40%), zinc (Zn) (283.7%), magnesium (Mg) (34.3%), and sodium (Na) (250.2%), whereas the carbon (C) percentages were around 1%. The most significant enrichment factors occurred for Ba, Cr, Pb, Zn, Mg, and Na. The highest rates occurred in geoaccumulation where the sediments were enriched by zinc. According to the principal guidelines, the concentrations obtained for cadmium (Cd), Cr, Cu, Ni, and Zn can cause adverse environmental impacts.     

Total Contents and Sequential Extraction of Heavy Metals in Soils Irrigated with Wastewater,Akaki, Ethiopia

The Akaki River, laden with untreated wastes from domestic, industrial, and commercial sources, serves as a source of water for irrigating vegetable farms. The purpose of this study is to identify the impact of waste-water irrigation on the level of heavy metals and to predict their potential mobility and bioavailability. Zn and V had the highest, whereas Hg the lowest, concentrations observed in the soils. The average contents of As, Co, Cr, Cu, Ni, Zn, V, and Hg of both soils; and Pb and Se from Fluvisol surpassed the mean + 2 SD of the corresponding levels reported for their uncontaminated counterparts. Apparently, irrigation with waste water for the last few decades has contributed to the observed higher concentrations of the above elements in the study soils (Vertisol and Fluvisol) when compared to uncontaminated Vertisol and Fluvisol. On the other hand, Vertisol accommodated comparatively higher average levels of Cr, Cu, Ni, Zn, etc V, and Cd, whereas high contents of Pb and Se were observed in Fluvisol. Alternatively, comparable levels of Co and Hg were found in either soil. Except for Ni, Cr, and Cd in contaminated Vertisol, heavy metals in the soils were not significantly affected by the depth (0–20 and 30–50 cm). When the same element from the two soils was compared, the levels of Cr, Cu, Ni, Pb, Se, Zn, V, Cd at 0–20 cm; and Cr, Ni, Cu, Cd, and Zn at 30–50 cm were significantly different. Organic carbon (in both soils), CEC (Fluvisol), and clay (Vertisol) exhibited significant positive correspondences with the total heavy metal levels. Conversely, Se and Hg contents revealed perceptible associations with carbonate and pH. The exchangeable fraction was dominated by Hg and Cd, whereas the carbonate fraction was abounded with Cd, Pb, and Co. conversely, V and Pb displayed strong affinity to reducible fraction, where as Cr, Cu, Zn, and Ni dominated the oxidizable fraction. Cr, Hg, Se, and Zn (in both soils) showed preference to the residual fraction. Generally, a considerable proportion of the total levels of many of the heavy metals resided in non residual fractions. The enhanced lability is generally expected to follow the order: Cd > Co > Pb > Cu > Ni > Se > V and Pb > Cd > Co > Cu > Ni > Zn in Vertisol and Fluvisol, respectively. For the similar wastewater application, the soil variables influence the status and the distribution of the associated heavy metals among the different soil fractions in the study soils. Among heavy metals that presented relatively elevated levels and with potential mobility, Co, Cu, Ni (either soil), V (Vertisol), Pb, and Zn (Fluvisol) could pose health threat through their introduction into the food chain in the wastewater irrigated soils.     

Concentration and chemical speciation for the determination of Cu,Zn, Ni,Pb and Cd from refuse dump soils using the optimized BCR sequential extraction procedure

The optimized BCR sequential extraction procedure (proposed by the Standards, Measurements and Testing Programme (SM&T) of the European Union) was applied to seven topsoil samples from refuse dump sites for the determination of Cu, Zn, Ni, Pb and Cd. The metals were partitioned into four operationally defined chemical fractions: acid extractable, reducible, oxidizable and residual, and analysed using flame atomic absorption spectrophotometry, FAAS. The results were compared with total metal concentrations obtained using HNO₃, HClO₄ and HF digestion procedures. Results for total metal analysis ranged from - 15.55 to 43.45 for Cu, 37.15 to 222.35 for Zn, 5.15 to 12.10 for Ni, 10.30 to 93.05 for Pb and 0.35 to 3.75 for Cd in μgg⁻¹ dry weight. The results of the partitioning study showed that zinc prevailed in the more soluble fractions and was distributed between the acid-extractable (32.4%) and the reducible (40.3%) fractions, whereas Pb was distributed mainly in the reducible fraction. Copper and nickel were predominantly associated with the reducible and residual fractions - 53.4, 33.3 and 51.1, 24.1% respectively. The ranking of the four fractions for the partitioning of cadmium was: reducible > residual > oxidizable > acid extractable. The percentage recovery for all metals when comparing total metal concentration with the fractional sum of the optimized BCR procedure, were of the order: Zn(93%) > Pb(83%) > Cu(78) > Cd > (68%) > Ni(63%).     

样品保存方法对阳极溶出伏安法测定时的影响

对海水中Cu、Pb、Zn、Cd的日常监测分析方法进行了调查,结果表明在调查范围内阳极溶出伏安法使用数量最高。通过实验研究了不添加保存剂、加浓HNO3、加浓HClO4对阳极溶出伏安法测定海水Cu、Pb、Zn、Cd的影响。发现不添加保存剂时4种金属峰电位变化范围大、出现频次分散,分析方法灵敏度下降。不同类型酸对阳极溶出伏安法测定Pb、Zn、Cd时的峰电位变化影响不大,加浓HNO3时Cu的峰电位变化小于加浓HClO4。根据实验结果,推荐使用保存剂为浓HNO3。     

Sorption of hazardous metals from single and multi-element solutions by saltbush biomass in batch and continuous mode: interference of calcium and magnesium in batch mode

Batch studies were performed to determine the interference of calcium (Ca) and magnesium (Mg) on the sorption of Cu(II), Cd(II), Cr(III), Cr(VI), Pb(II), and Zn(II) [from CuSO(4), K(2)Cr(2)O(7), Pb(NO(3))(2), Cr(NO(3))(3), ZnCl(2), and Cd(NO(3))(2)] by saltbush (Atriplex canescens) biomass. The results demonstrated that Ca and Mg at concentrations of at least 20 times higher than the concentration of most of the target metals did not interfere with the metal binding. The data show that the batch binding capacity from a multimetal solution at pH 5.0 was (micromol/g) about 260 for Cr(III) and Pb, and about 117, 54, and 49 for Cu, Zn, and Cd, respectively. The use of 0.1M HCl allowed the recovery of 85-100% of the bound Cu, Cr(III), and Pb, and more than 37% of the bound Cd and Zn. The column binding capacity for Pb was about 49 micromol/g from both the single and multimetal solutions, while it was, respectively about 35 and 23 micromol/g for Cr(III). The binding capacity for Cu and Zn from the single and multimetal column experiments was 35 micromol/g and less than 10 micromol/g, respectively. The stripping data from the single column experiment showed that 0.1M HCl allowed the recovery of all the bound Cu and Zn, 90% and 74% of the bound Pb and Cr(VI), respectively, and less than 25% of the bound Cd and Cr(III), while the stripping from the multimetal experiment showed that 0.1M HCl allowed the recovery of all the bound Cu and about 74%, 54%, 43%, and 40% of the bound Pb, Zn, Cd, and Cr(III), respectively.     

Distribution of heavy metals in sediments of Igbede, Ojo and Ojora rivers of Lagos, Nigeria

The distribution of some heavy metals, namely Cd, Pb, Zn, Fe, Cu, Cr and Mn in epipellic sediments of Igbede, Ojo and Ojora rivers of Lagos was studied weekly in the early summer (November) of 2003. The levels of selected trace metals were determined using Atomic Absorption Spectrophotometer (UNICAM 969 AAS SOLAR). Trends in heavy metal burdens in the sediments revealed weekly variations in all the rivers assessed. Statistical analyses also showed different mean levels of trace metals in the aquatic environments, the distribution of which followed the sequence Fe > Zn > Mn > Pb > Cu > Cr > Cd, Fe > Zn > Cu > Mn > Pb > Cr > Cd and Fe > Zn > Mn > Cu > Cr > Pb > Cd in Igbede, Ojo and Ojora rivers respectively. Fe recorded the highest concentration levels (1,582.95 ± 96.57 μ g/g–1,910.34 ± 723.19 μ g/g) in all the sediments investigated while the Cd levels (0.06 ± 0.10 μ g/g–0.47 ± 0.36 μ g/g) were the lowest. Expectedly, trace metal concentrations in fine grain muddy sediments of the Igbede and Ojo coastline were much higher than those of Ojora which consist of coarse and sandy deposits covering the near shore area. Generally, the results obtained fell within tolerable limits stipulated by World Health Organization (WHO).