Admium and lead sorption and desorption characteristics of four soils from the Yangtze Delta, East China     

《中国地球化学学报》2006,25(B08):79-79

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Effects of pH and Ca competition on complexation of cadmium by fulvic acids and by natural organic ligands from a river and a lake     

Jun Cao  Hanbin Xue  Laura Sigg 《Aquatic Geochemistry》2006,12(4):375-387

The technique of competitive ligand-exchange/anodic stripping voltammetry (CLE-SV) was used to investigate effects of pH and Ca concentration on cadmium complexation by fulvic acid (FA), as well as Cd speciation in two different freshwaters, a hardwater Lake Greifen and a softwater River Wyre. Binding of Cd to Suwannee river FA (10 mg/l) was determined at different pH (7–8.5) and in the presence of various concentration of Ca²⁺ (0–2 mmol/l). The results from one-ligand discrete models were compared to simulations by the WHAM VI model. In Lake Greifen, the determined dissolved [Cd²⁺] ranged from 10⁻¹³ to 10⁻¹² mol/l, and the conditional stability constant with natural ligands was log K _CdL about 9.5–10.5 (pH 8.6–8.8) with ligand concentrations of 1.2–7.8 × 10⁻⁶ mol/g C. In the softwater River Wyre, dissolved [Cd²⁺] ranged from 4 × 10⁻¹² to 1 × 10⁻¹¹ mol/l, and the ligands were weaker (log K _CdL 8.9–9.8, pH 8.0) with lower ligand concentrations (0.9–2.3 × 10⁻⁶ mol/g C). The titration curves of FA samples were close to the simulated curves by the WHAM VI model at pH 8.0–8.5, but deviated more from the model at lower pH, indicating that the results determined with CLE-SV for Cd-FA complexation are relevant to the data base in the model. Calculation of the Ca competition for Cd binding by FA showed a competition effect of similar strength as the measured one, but indicated a systematic difference between measured and modeled data at pH 7.5. Using the WHAM model for comparison with FA, the complexation of Cd by the River Wyre ligands was close to that of FA, whereas stronger complexation was observed in the Lake Greifen water. These differences may originate from different ligand composition in the lake and the river.  相似文献   

闪锌矿的Cd含量与颜色关系   总被引：2，自引：0，他引：2  

刘铁庚  叶霖  沈能平  周家喜 《矿物学报》2015,35(1):51-55

过去人们普遍认为黑色闪锌矿贫镉,浅色闪锌矿富镉。笔者统计了国内外74个矿床,385个Cd含量数据。其中33个矿床有不同颜色闪锌矿的Cd含量数据37组。闪锌矿从黑色到浅色,Cd含量依次降低的有15矿床,17组数据,占统计矿床的44.1%,数据组的48.6%;Cd含量逐渐增加有14个矿床,14组数据,分别占统计矿床的45.5%,数据组的38.9%;Cd含量先降后升,黑色闪锌矿含量最高的有2个矿床,2组数据,分别占统计矿床的6.1%,数据组的5.7%;Cd含量先减后增,浅色闪锌矿含量最高和先升后降,褐色闪锌矿含量最高的各有一个矿床,一组数据,分别各占统计矿床的3.0%,占数据组的2.9%。由此看来,黑色闪锌矿与浅色闪锌矿的Cd含量无明显差异,说明闪锌矿的Cd含量与其颜色无明显关系。  相似文献   

Joint toxic effects of heavy metals and atrazine on invasive plant species <Emphasis Type="Italic">Solidago Canadensis L</Emphasis>.     

HAN Zhaoxiang*  HE Gu  ong  WANG Jiahong  Lü Chunxia School of Chemical Engineering  Huaihai Institute of Technology  Lianyungang  China School of the Environment  Nanjing University  Nanjing  China Jiaonan Agricultural Bureau  Qingdao  China 《中国地球化学学报》2011,30(4):523-530

In this study, the joint effects of Cd(Ⅱ), Pb(Ⅱ) and atrazine (ATR) on Solidago Canadensis L. were investigated. The results showed that soil containing Cd, Pb and ATR could inhibit root elongation of Solidago Canadensis L., and that there was a positive linear relationship between the inhibitory rate of root elongation and the concentrations of Pb(Ⅱ). The mixture of Cd(Ⅱ) and Pb(Ⅱ)-ATR in soil showed a significant adverse effect on root and shoot biomass of Solidago Canadensis L. Acetylsalicylic acid (ASA) contents increased slightly at the lower concentrations of Cd(Ⅱ)-ATR, then decreased when Cd(Ⅱ)-ATR concentrations were higher than those of 1.0 TUmix(Cd+ATR). The toxic effect of Pb(Ⅱ)-ATR on the ASA contents of Solidago Canadensis L. was greater than that of Cd(Ⅱ)-ATR. Soluble sugar contents firstly decreased and then increased with increasing concentrations of Cd(Ⅱ)-ATR and displayed fluctuation with increasing concentrations of Pb(Ⅱ)-ATR. Total protein contents in-creased with increasing concentrations of Cd(Ⅱ) and Pb(Ⅱ)-ATR , relative to the control sample. The NP-SH con-tents showed a significant increase up to 12.2 mg/gfw of Cd(Ⅱ)-ATR, followed by a significant decline to 4.5 mg/gfw after 14 days of exposure. The effect of Pb(Ⅱ)-ATR was similar to that of Cd(Ⅱ)-ATR but the amount of NP-SH was not higher than that of Cd(Ⅱ)-ATR.  相似文献   

铜陵市大气降尘中Cd元素污染特征及其对土壤的影响   总被引：2，自引：0，他引：2       下载免费PDF全文

殷汉琴  周涛发  陈永宁  陈富荣  袁峰  李湘凌 《地质论评》2011,57(2):218-222

为了评价有色金属矿山城市大气降尘中重金属元素的污染状况、来源及其对土壤重金属累积的影响,分析测试了铜陵市大气降尘样品中Cd元素的含量.分析结果表明,降尘样品中Cd元素的平均含量为16.44/μg/g,明显高于安徽省江淮流域多目标调查中铜陵土壤Cd元素的平均含量;降尘中Cd元素含量较高的样品出现在矿山和冶炼厂附近.用富集...  相似文献   

镉对共培养赤潮微藻的急性毒性效应研究——基于流式细胞术的研究探讨     

苏婧 《海洋湖沼通报》2012,(2):107-113

在实验条件下,利用流式细胞术探讨了重金属镉对赤潮异弯藻和微小原甲藻的种群增长和种间竞争的影响,实验结果如下:(1)共培养的条件下,Cd2+胁迫前后2种微藻的细胞体积和细胞内容物复杂程度没有一致的变化规律,但叶绿素a含量和存活率均呈下降趋势;(3)叶绿素a荧光值和存活率可以考虑作为Cd2+胁迫增强的微藻生物标志物系统的指标。  相似文献   

Sorption Kinetics of Cd(II) Species on Humic Acid‐Based Sorbent          下载免费PDF全文

Sri Juari Santosa 《洁净——土壤、空气、水》2014,42(6):760-766

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云南岩溶区As、Cd元素异常特征   总被引：2，自引：1，他引：1  

王宇  彭淑惠  杨双兰 《中国岩溶》2012,31(4):377-381

云南岩溶区水系沉积物中As、Cd元素含量分别为6.7~14.9ppm和0.14~0.21ppm,普遍高于省内其它地区。云南不同岩溶区As、Cd元素含量高异常还有较大的差异。As、Cd元素的高异常以滇东南岩溶区最为明显,异常幅度最大;其次为滇东岩溶区、滇西北以及滇西保山—沧源岩溶区;滇东北地区Cd异常较为突出,而As异常较弱。一般从岩石到土壤As、Cd元素呈富集态势,富集约4~5倍。通过对小江流域泸西As、Cd元素高异常区的地球化学和地质环境分析,发现农作物对As吸收量不大,超标率为14.8%;但对Cd元素吸收远高于As元素,超标率高达74.1%。通过对比分析,认为岩溶区碳酸盐岩As、Cd元素的高背景含量(As含量12.89~28.86ppm、Cd含量0.031~0.314ppm)是其风化形成的土壤中As、Cd元素含量高异常的根本来源,As、Cd元素主要通过粘土矿物和有机质的吸附累积而富集。   相似文献   

有机-中性化技术对旱作土壤镉有效性的长期影响   总被引：1，自引：1，他引：0  

杜葱远  林珍珠  梁巧凤  陈炎辉  王果 《亚热带资源与环境学报》2009,4(1)

采用连续提取法测定了土壤中镉(Cd)的形态,以研究石灰或钙镁磷肥与猪粪或泥炭混施对田间条件下Cd污染土壤中Cd有效性的抑制效果.处理的第1年,猪粪使石灰对土壤Cd有效性的抑制率从18.2%提高到22.3%,使钙镁磷肥的抑制率从37.1%提高到50.8%;泥炭使石灰的抑制率从18.2%提高到57.1%,使钙镁磷肥的抑制率从37.1%提高到49.3%.处理的第4年,猪粪使石灰对土壤Cd有效性的抑制率从32.3%提高到44.2%,使钙镁磷肥的抑制率从38%提高到51.6%;泥炭使石灰的抑制率从32.3%提高到45.4%,使钙镁磷肥的抑制率从38%降低到8.2%.上述结果表明猪粪和泥炭在施用后第1年均可增强石灰和钙镁磷肥对土壤Cd有效性的抑制效果.到第4年,猪粪仍然促进了石灰和钙镁磷肥对Cd有效性的抑制效果,而泥炭增强了石灰的抑制效率但降低了钙镁磷肥的抑制效果.研究结果证明了有机-中性化技术对Cd污染土壤的修复效果.石灰和钙镁磷肥大幅度提高了土壤Cd的碳酸盐结合态与专性吸附态,从而降低了土壤Cd的有效态(水溶态+交换态).  相似文献   

出芽短梗霉吸附水体中共存Cr（Ⅵ）、Cd（Ⅱ）重金属离子研究   总被引：5，自引：2，他引：3  

张玉玲张兰英  王显胜王晓晖 高松 《吉林大学学报(地球科学版)》2005,35(3):403-406

利用出芽短梗霉进行吸附水体中Cr（Ⅵ）、Cd（Ⅱ）共存离子实验, Cr（Ⅵ）、Cd（Ⅱ）毒性浓度均为300 mg/L时,菌种生长良好。吸附性能实验结果表明：出芽短梗霉吸附水中Cr（Ⅵ）的最佳条件是pH值为3.0、时间为2 h、温度为30℃,吸附量为8.575 mg/g;吸附Cd（Ⅱ）的最佳条件是pH为5.0、时间为30 min、温度为30℃,吸附量为15.49 mg/g。  相似文献