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441.
We quantified the contents of four toxic metals in cosmetic products that are commercially available in Jordan; 112 cosmetics, representing 10 product types, were tested in triplicate after acid digestion using inductively coupled plasma optical emission spectrometry and a mercury analyzer. Ni was most abundant, detected in 104/112 (92.8%) products (average, 2.32 ppm; and median, 1.47 ppm); 66/112 (59%) contained >1 ppm and 13/112 (11.6%), >5 ppm Ni. Cd was second-most abundant, detected in 86/112 (76.7%) products (mean, 1.71 ppm; range from< detection limit [DL] to 18.07 ppm); 16 products (14.3%) exceeded the 3 ppm suggested limit. Pb was detected in 82/112 (73.2%) products (mean, 7.8 ppm; range, < detection limit to 190.43 ppm); 20/112 (17.8%) contained more than the suggested 10 ppm limit. Hg was least-frequently detected, present in 29/112 (25.9%) and at >3 ppm in 15/112 (13.4%) products. The highest content of Hg was observed in skin lightening creams (mean concentration, 1,008 ppm). Hg was detected in 20 (62.5%) of the 32 skin lightening creams tested, of which 11/32 (34.4%) contained > 3 ppm Hg. Of the 112 cosmetics tested, 17 (15.1%) products contained Ni, Pb, Cd, and Hg; 19/112 (16.9%) contained Cd, Pb, and Hg –no product exceeded the maximum acceptable limits for all three elements, and 9/112 (8%) products exceed the maximum recommended levels for at least two elements (Hg, Cd, and Pb).  相似文献   
442.
• DTPA and NH4OAc, HNO3 and EDTA, and MgCl2 and NH4NO3 had similar behavior. • In NH4OAc, DTPA, and EDTA, the possibility of re-adsorption of trace elements is low. • CaCl2 may be more suitable than other extracts in calcareous soils. Understanding trace elements mobility in soils, extracting agents, and their relationships with soil components, are essential for predicting their movement in soil profile and availability to plants. A laboratory study was conducted to evaluate extractability of cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), and zinc (Zn) from calcareous soils utilizing various extracting agents to be specific CaCl2, DTPA, EDTA, HNO3, MgCl2, NaNO3, NH4NO3, and NH4OAc. Cluster analysis indicated that DTPA and NH4OAc, HNO3 and EDTA, and MgCl2 and NH4NO3 extracting agents yielded comparative values, whereas NaNO3 and CaCl2 have shown different behavior than other extracting agents for all studied trace elements. The speciation of extracted trace elements in solutions indicated that in the CaCl2, NaNO3, NH4NO3, and MgCl2 extracting agents most extracted Cd, Co, Ni, Zn, and part of Cu were as free ions and may be re-adsorbed on soils, leading to lower extractability, whereas, in the case of HNO3 extracting agent, the likelihood of re-adsorption of trace elements may be little. The results of speciation of trace elements using NH4OAc, DTPA, and EDTA extracting agents showed that Me-(Acetate)3, Me-(Acetate)2(aq), Me(DTPA)3, Me(EDTA)2, and MeH(EDTA) complexes dominated in solutions indicating that the extracted trace elements may not be re-adsorbed on soils, leading to higher extractability. The results of this study are useful for short and long-term evaluations of trace elements mobility and further environmental impacts.  相似文献   
443.
采用氦气碰撞模式和内标法抑制ICP-MS测试地下水中痕量元素的多原子离子干扰和基体效应。探讨He流量、内标元素、宏量离子等因素对测定的影响,结果表明:187Re、208Pb响应值与He流量呈线性下降模型,其他离子为指数下降模型,He流量为2. 5 m L/min~3. 0 m L/min时满足地下水质量分级测定要求;内标元素的响应因子随质量浓度的增大而降低,16. 0μg/L以上时趋于稳定;酸度显著影响测定误差,选用较大质量数的内标元素和保持样品酸度的一致可提高测定的准确度。  相似文献   
444.
Waste printed circuit boards contain valuable metals such as Au, Pd, Ag, and Cu that can be reutilized and harmful elements such as Pb, Br, and Cr that must be removed from the viewpoint of environmental conservation. In this research, we examined a method that separates the materials from printed circuit boards contained in discarded personal computers. After cutting the printed circuit boards to a size of 20 × 20 mm, they were heated at 873 K under an Ar atmosphere to remove organic resins containing elements such as C, H, and N. After heat treatment, the printed circuit boards were crushed using a planetary ball mill and the pulverized powders were filtered. The fraction with a granularity of greater than 250 μm was separated into magnetic and nonmagnetic materials by a magnetic field. Because the fraction with a granularity of less than 250 μm contained 39 mass% of C, it was heated at 1273 K in an atmosphere of 95% Ar and 5% O2 to allow carbon combustion to take place, followed by metal reduction processing at the same temperature in an atmosphere of 97% Ar and 3% H2. The basicity of the resulting powder was adjusted and the powder was heated at 1773 K under an Ar atmosphere. The proposed method separated the slag and metal, and 80% of the valuable metals contained in printed circuit boards could be collected.  相似文献   
445.
This study characterized the dry deposition flux and dry deposition velocity (Vd) of metallic elements attached on particulate matter. Specifically, large particles (>10 μm), coarse particles (10 μm~2.5 μm), and fine particles (<2.5 μm) were studied at the Gong Ming Junior High School (Taichung Airport) and Taichung Harbor sampling sites in central Taiwan. Ambient air samples were collected to determine total suspended particulate matter (TSP), dry deposition plate (DDP), Vd, coarse particulate matter (PM2.5–10) and fine particulate matter (PM2.5), and metallic elements concentrations at the Airport and Taichung Harbor sites between June 17, 2013, and November 14, 2013. The results revealed that the average TSP, DDP, Vd, PM2.5–10, and PM2.5 particulate at the Airport were 54.55 (μg/m3), 902.25 (μg/m2-min), 17.11 (m/sec), 0.003 (μg/m3), and 0.010 (μg/m3), respectively; while these values at Taichung Harbor were 63.66 (μg/m3), 539.69 (μg/m2-min), 9.94 (m/sec), 0.003 (μg/m3), and 0.014 (μg/m3), respectively. In addition, the results showed that the average Cu and Pb concentrations were higher than Cr, Ni, and Cd for both the airport and harbor sampling sites. Furthermore, Cr, N, Cu, Cd, and Pb had the highest average concentrations versus those reported for other study areas, with one exception: The results obtained in Kacanik, Kosovo, during 2005. The average metallic elements concentrations order was Cu > Pb > Cr > Ni > Cd.  相似文献   
446.
微分脉冲阴极溶出伏安法测定环境水样中的痕量硒   总被引:14,自引:0,他引:14  
徐晖  张必成  王升富 《环境化学》2001,20(4):386-391
采用微分脉冲阴极溶出法测定环境水样中的痕量硒,以银电极为工作电极,在酸性介质0.06mol.l^-1HCl-0.07mol.l^-1HNO3溶液中于-0.35V(vs SCE)处富集20min,使Se(IV)电沉积为硒化银,然后,以40mV.s^-1的扫速,在碱性介质2.0mol.l^-1NaOH溶液中阴极溶出至-1.2V(vsSCE),硒化银被还原为银的溶出峰电位约为-0.85V(vs SCE),硒的分析校正曲直到40ng.ml^-1仍然成线性,检测下限为11.5pg.ml^-1,相关系为0.9982,灵敏度为10.93uA/ng.ml^-1,20ng.ml^-1的RSD(n=5)为1.26%,检出限(3σ为3.46pg.ml^-1,环境水样中常见离子的存在不干扰痕量硒的测定。  相似文献   
447.
Rainwater samples were collected from Tamale town in the 1997 and 1998 rainy seasons. During this period road construction in the Tamale area resulted in the generation of suspended dust in the atmosphere. Analysis of the samples for major ions showed elevated levels of Cl. Ion ratios with Cl (Na+/Cl, K+/Cl, Ca2+/Cl/Cl Mg2+/Cl and SO4 2–/Cl) in rainwater samples were higher than the corresponding ratios in seawater. Some samples also showed elevated concentrations of Fe, Mn, Al and Zn, all of which except Zn showed a correlation with the dry periods between rainfall events. Consequently, it was concluded that dust generated from lateritic soils was probably the major cause of the increase in concentration of these metals. Aluminium and Fe concentrations were observed to be higher than the World Health Organization drinking water guide limits.  相似文献   
448.
排水对三江平原沼泽湿地土壤中化学元素的影响   总被引:2,自引:0,他引:2  
以三江平原沼泽湿地生态试验站为研究基地 ,选择典型采样点 ,对排水沟土壤、沼泽土壤、沼泽化草甸土壤 (共有 6个采样点 ,2 8个样品 )进行测试 ,分析土样中主要离子 (HCO3- 、Cl- 、NO3- 、SO4 2 - 、Ca2 +、Mg2 +、K+、Na+)含量、重金属 (铁、锰、锌、铜 )含量、营养元素含量、有机质含量以及土壤pH值 ,研究沼泽排水对沼泽土壤中的化学元素含量的影响。研究结果表明 ,排水使沼泽土壤丧失大量的化学元素  相似文献   
449.
林兰稳 《生态环境》2001,10(1):55-56
通过对糯米糍荔枝叶片、果皮、土壤中矿质元素含量的研究,探讨矿质营养对荔枝裂果率的影响。初步探明糯米糍荔枝叶片中的钙、镁、硼含量,果皮中的氮钾比,以及土壤中的N/K比、有机质、交换性钙含量影响其裂果率。  相似文献   
450.
The influences of coal-mine hollow fills and associated settling ponds in three headwater streams were assessed in southern West Virginia, USA. Fill drainage waters had elevated conductivities and metal concentrations, compared to a regional reference. Benthic macroinvertebrate richness was not affected consistently by the hollow fill drainages, relative to a regional reference, although a more tolerant community, lacking in Ephemeroptera taxa at most locations, was evident. Collector-filterer populations were elevated at monitoring stations directly below the settling ponds, indicating that the ponds’ presence influenced macroinvertebrate community structure by means of organic enrichment. Corbicula fluminea growth was enhanced in monitoring locations directly below the settling ponds, also an apparent result of organic enrichment. Results of acute water column toxicity testing with Ceriodaphnia dubia, sediment chronic toxicity testing with Daphnia magna, and in-situ ecotoxicological assessments with C. fluminea demonstrated no mortality or toxic influence at most of the sites tested below the ponds. The settling ponds appear to serve as sinks in collecting some, but not all, trace metals.  相似文献   
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