首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6篇
  免费   0篇
废物处理   1篇
评价与监测   4篇
社会与环境   1篇
  2014年   1篇
  2009年   1篇
  2007年   1篇
  2005年   1篇
  2003年   2篇
排序方式: 共有6条查询结果,搜索用时 15 毫秒
1
1.
A new method for separation and preconcentration of trace amounts of Cu(II), Ni(II), Pb(II), Cd(II) and Mn(II) ions in various matrices was proposed. The method is based on the adsorption and chelation of the metal ions on a column containing Amberlite XAD-1180 resin impregnated with 1-(2-thiazolylazo)-2-naphthol (TAN) reagent prior to their determination by flame atomic absorption spectrometry (FAAS). The effect of pH, type, concentration and volume of eluent, sample volume, flow rates of sample and elution solutions, and interfering ions have been investigated. The optimum pH for simultaneous retention of all the metal ions was 9. Eluent for quantitative elution was 20 ml of 2 mol l(-1) HNO(3). The optimum sample and eluent flow rates were found as 4 ml min(-1), and also sample volume was 500 ml, except for Mn (87% recovery). The sorption capacity of the resin was found to be 0.77, 0.41, 0.57, and 0.30 mg g(-1) for Cu(II), Ni(II), Cd(II), and Mn(II), respectively. The preconcentration factor of the method was 200 for Cu(II), 150 for Pb(II), 100 for Cd(II) and Ni(II), and 50 for Mn(II). The recovery values for all of the metal ions were > or = 95% and relative standard deviations (RSDs) were < or = 5.1%. The detection limit values were in the range of 0.03 and 1.19 microg l(-1). The accuracy of the method was confirmed by analysing the certified reference materials (TMDA 54.4 fortified lake water and GBW 07605 tea samples) and the recovery studies. This procedure was applied to the determination of Cu(II), Ni(II), Pb(II), Cd(II) and Mn(II) in waste water and lake water samples.  相似文献   
2.
Cadmium pollution resulted from fertilizer applications were studied by determining cadmium levels in agricultural and non-agricultural soils of Bafra and Çar?amba plains. Soil samples of 68 were collected from agricultural (34) and non-agricultural (34) areas. The sample of 2 g was placed in a test tube and digested with hydrochloric acid and nitric acid mixture (3:1, v/v) in an aluminum block. Taking up the evaporated residue was dissolved in 1% nitric acid and total cadmium concentrations were determined with GF-AAS. Mean level of cadmium contents were found in agricultural areas 0.162?±?0.078 for Çar?amba and 0.433?±?0.288 mg kg?1 for Bafra. The accuracy of the method was tested with determining cadmium contents of standard reference material and cadmium spiked soil samples.  相似文献   
3.
The leaves of Robinia pseudo-acacia L. (Fabaceae) were evaluated as a biomonitors of heavy metal contamination in Denizli city, Turkey. Concentrations of Fe, Zn, Pb, Cu, Mn and Cd were determined in washed and unwashed leaves and soils collected from a wide range of sites with different degrees of metal pollution (industry, urban roadside, suburban) and from a rural (control) site by atomic absorption spectrometry. All the elements that measured were found to be at high levels in samples collected at industrial sites, except for lead and copper which were found at high levels in samples collected from urban roadsides that associated with the road traffic. The strong correlation between the degree of contamination and concentrations in all plant leaves assessed display that the leaves of R. pseudo-acacia reflect the environmental changes accurately, and that they seem as an effective biomonitor of environmental quality in areas subjected to industrial and traffic pollutions.  相似文献   
4.
Ethylenediaminetetracetic acid (EDTA) is one of the most common chelators used to bind the metal ions in extremely stable complexes in heavy metal contaminated soils and thus to remediate such substrates. EDTA forms water soluble complexes with many metal ions and it is used to release the various metals. In this study, EDTA extraction of copper, chromium, and arsenic from chromated copper arsenate (CCA-C) treated wood was evaluated using batch leaching experiments. CCA-treated wood samples were extracted with eight different concentrations of EDTA for 4, 8, 18, and 24 h at room temperature. Exposing CCA-treated chips and sawdust to EDTA extraction enhanced removal of CCA components compared with extraction by deionized water. Grinding CCA-treated wood chips into 40-mesh sawdust provided greater access to and removal of CCA components. Extraction with 1% EDTA solution for 24 h removed 60% copper, 13% chromium, and 25% arsenic from treated chips. EDTA extraction of treated sawdust samples resulted in 93% copper, 36% chromium, and 38% arsenic removal. CCA leaching from treated wood blocks was also evaluated according to modified AWPA E11-99 standard test method of determining the leachability of wood preservatives. Leaching of CCA components from treated wood blocks with 1% EDTA solution for 14 days caused more copper leaching compared to leaching with deionized water. Leaching with 1% EDTA for 14 days removed 53% copper from the blocks whereas 14% copper was leached from the blocks with deionized water. The results suggest that EDTA extraction removes significant quantities of copper from CCA-treated wood. Thus, EDTA could be important in the remediation of wood waste treated with the newest formulations of organometalic copper compounds and other water-borne wood preservatives containing copper.  相似文献   
5.
The aim of this study was to elucidate the amount of metal released at each step by using different extractants in three sequential extraction schemes for the partitioning of metal contents of car park deposited dust samples. For this purpose, three different sequential extraction procedures (SEP) were employed for the metal fractionation in car park dust samples collected from the campus of Erciyes University, Kayseri, Turkey. While two of the sequential extraction procedures contain five steps the other, namely the BCR sequential extraction scheme, has three steps. The first two methods fractionate metals to be exchangeable, bound to carbonates, bound to Mn oxides, bound to Fe oxides and bound to organic matter, and the BCR protocol fractionates the metals as acid soluble and exchangeable, reducible, and oxidisable. Determination of the metals Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn was performed by flame atomic absorption spectrometry (FAAS). The results obtained by the three methods were compared and showed that the amount of metal released at each step of the leaching procedure depended both on the type of reagents used and the sequence in which they were applied. The most mobile elements were Cd, Pb and Zn which are metals potentially toxic to the environment and are also known to originate from traffic. The calculated enrichment factors for Cd and Pb were substantially high (73.5-187 and 18.4-27.5, respectively) and somewhat lower for Zn (5.1-6.8). These results confirm that they are important metal pollutants for car parks. Detection limits and recoveries were found in the range of 0.01-1.39 microg ml(-1) and 68-126%, respectively, for the metals studied and the three sequential extraction procedures.  相似文献   
6.
Total diet study approach was used to assess the dietary intakes of pesticide residues among the select population in Hyderabad. When assessed by a food frequency questionnaire, it was found that the food intakes varied among five socioeconomic sections (SES). Therefore, we intended to compare the intakes of pesticide residues through these foods among the five SES. A total of 195 foods from different markets were collected and analyzed for 19 pesticides. The residues were analyzed with a gas chromatograph and were confirmed with mass spectrometry. About 51 % of the samples were detected with one or more residues. Thirteen out of the 19 residues were present in levels above detection limits in various concentrations. The median concentrations of the residues in all the samples tested, ranged from 0.00010 to 0.33 mg/kg. Highest median concentration was for β-HCH in water samples. Exposures to all the residues were below the respective ADIs at both mean and 95th percentile levels of food intakes with highest estimated dietary intakes (EDIs) of β-HCH in both the cases. The EDIs of β-HCH were the highest among all the residues at both the intake levels among all the SES. The EDIs of β-HCH were significantly higher in lower SES than higher SES possibly due to the consumption of rice cooked in water contaminated with β-HCH. EDIs for other residues did not differ significantly among the five SES.  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号