德阳镉污染农田区生态安全性及居民健康风险评价   总被引：8，自引：3，他引：5  

金立新  侯青叶  包雨函  徐洲  李忠惠  杨忠芳  陈德友 《现代地质》2008,22(6)

对四川德阳地区土壤镉等重金属污染区大米、小麦安全性进行了评价,并建立了水稻籽实镉含量与根系土镉、有机质含量、pH值的回归方程,据此预测德阳地区水稻镉超标面积。根据当地居民主食(大米、小麦)镉等重金属元素的摄入量,对镉污染区人体健康风险进行了评价。研究表明,德阳地区大米、小麦重金属污染均以镉为主。预测水稻镉超标面积达1 547.95 km2,占研究区面积的73.47%。人发镉等重金属元素存在明显异常。人发镉含量高值区与土壤镉异常和居民主食镉摄入量高值区分布有一致性。什邡市、绵竹市、安县、旌阳区、广汉市居民主食(大米、小麦)镉摄入量均超标2~10倍。重金属污染造成人体健康风险最高的是绵竹、什邡地区,其次是旌阳区。  相似文献   

多重分形方法识别铜陵矿区土壤中Cd的地球化学异常   总被引：4，自引：0，他引：4  

白晓宇  袁峰  周涛发  李湘凌  张鑫  范裕  陈兴仁  陈永宁  陈富荣 《矿物岩石地球化学通报》2008,27(3)

土壤元素异常下限值的确定对环境地球化学评价具有重要意义。传统异常下限值计算方法仅适用于元素含量数据呈正态分布的情况,而事实上土壤元素含量的空间分布极其复杂,很可能具有多重分形分布特征。本文利用校正累积频率分形方法确定铜陵矿区土壤中Cd的异常下限值为1．687mg／kg。并据此圈定了异常范围。与传统方法所确定的异常下限值及相应异常区域对比,分形方法圈定的异常区域范围更广,更为合理、有效。  相似文献   

Comparison of the Complexation of Cu and Cd by Humic or Fulvic Acids and by Ligands Observed in Lake Waters     

Hanbin Xue  Laura Sigg 《Aquatic Geochemistry》1999,5(4):313-335

The complexation of Cu and Cd by ligands observed in filtered unfractionated lakewaters is compared to the complexation by humic and fulvic acids. Complexation parameters (conditional stability constants and ligand concentrations) of Suwannee River fulvic acids (FA), purified peat humic acids (HA) and of ligands in lakewater samples have been determined using the same methods (ligand-exchange and CSV (cathodic stripping voltammetry) or ASV (anodic stripping voltammetry)), and the same titration ranges of Cu, Cd and organic carbon concentrations. The performance of the used techniques is first evaluated in FA and HA suspensions, and gives comparable results with the literature values for the same materials, according to published models (5-site model, NICA model) and parameters. Model calculations using the WHAM model for FA and HA (Tipping, 1994) are also presented. The comparison of titrations of FA and HA with Cu and Cd with those of lakewater samples indicates that stronger ligands than FA and HA are present at low concentrations in the lakewaters. Specific strong ligands occur in particular in eutrophic lake waters, whereas in a lake with higher metal concentrations and low biological productivity the ligands more closely match the fulvic acid characteristics.  相似文献   

Particulate Flux and Cd/P Ratio of Particulate Material in the Pacific Ocean     

Shinichiro Noriki  Kazuhiro Hamahara  Koh Harada 《Journal of Oceanography》1999,55(6):693-703

Time-series Mark 7 sediment traps were deployed at three stations at 0°N, 13°N and 48°N along 175°E to investigate seasonal and spatial variations of particulate material flux. Chemical analysis of particulate material was performed for four major chemical components, viz. opal, CaCO₃, organic material and clay minerals, Cd and P in the particulate material were also determined. We discuss the characteristics of particulate material at each site and the transportation of Cd and P to deep water by the particulate material. The total mass fluxes and variation of fluxes at each site reflect oceanographic conditions, such as biological productivity and kind of major planktonic organisms. At the northern site, large mass fluxes with a spring bloom and high ratios of opal are characteristic. Relatively small mass fluxes with high ratios of CaCO₃ are distinct, and dissolution of CaCO₃ due to sinking is recognized in the middle latitude and 0°N sites. The larger flux at the lower trap than the upper trap at the equatorial site suggests influence by lateral transport in the deep water. Distinctive decreasing Cd/P ratio and CaCO₃ concentrations in the particulate material with increasing depth suggests that the change of Cd/P ratio in the intermediate and deep water occurs through the dissolution of CaCO₃. The dissolved Cd/P ratios in the deep water are proportional to the age of the deep water in the Atlantic but not in the Pacific. This is explained by the difference of kinds of particulate material transporting Cd and P in the deep water between the oceans. That is, the major planktonic organisms are planktons of CaCO₃ tests in the Atlantic Ocean and diatoms of opal tests in the North Pacific Ocean.  相似文献   

Seasonal Cycles of Dissolved Cd, Mn and Zn in River Water Caused by Variations in pH Induced by Biological Activity     

Alain C. M. Bourg  Monika A. M. Kedziorek  Cathrine Crouzet 《Aquatic Geochemistry》2000,6(4):461-471

pH, dissolved oxygen, Zn, Cd and Mnwere measured once a month for 2.5 years in the LotRiver, France. The pH is controlled by biologicalactivity (photosynthesis and respiration). Dissolvedoxygen variations are due to a combination ofbiological activity and of the temperature dependenceof the oxygen solubility. pH is the master variablefor concentrations of aqueous Zn, Cd and Mn, thelowest concentrations being associated with thehighest pH values, which occur during the summer. pH-related processes rather than redox phenomenaexplain variations in dissolved Mn. Variations indissolved Zn and Cd are also controlled bypH-dependent reactions (possibly related to thedissolutive behavior of solid Mn).  相似文献   

电感耦合等离子体质谱仪测定可可西里冰芯样品中超痕量Cd和Pb   总被引：2，自引：2，他引：0  

李月芳  王宁练  姚檀栋 《冰川冻土》2002,24(1):93-97

介绍了利用电感耦合等离子体质谱仪(ICPMS)直接测定冰芯样品中超痕量重金属Cd和Pb的实验和分析方法,用国家一级标准溶液进行分析过程中的质量控制.仪器对测定浓度在20～100ng·L^-1之间Pb的分析精度<10%,对浓度在5～100ng·L^-1Cd的分析精度<10%,标准加入回收率在85%～107%之间.Cd和Pb的检测下限分别为0.62ng·L^-1和0.15ng·L^-1.初步探索了冰芯外部被污染部分的去除方法,给出了实验结果,并利用此方法对青藏高原马兰冰川的一根22m深冰芯进行了处理,分析了其中的Cd和Pb的浓度。  相似文献   

Cd²⁺和Cr⁶⁺对慈姑（Sagittaria sagittifolia L.）的毒害效应   总被引：3，自引：0，他引：3  

胡金朝  施国新  丁秉中  陈苏雅  许丙军  赵娟  吴国荣 《湖泊科学》2006,18(2):157-162

以水生经济植物慈姑（Sagittaria sagiuifolia L．）为实验材料,通过模拟水体Cd^2＋和Cr^6＋污染环境,研究了两种单一离子处理对慈姑的毒害影响．结果表明：随着水体Cd^2＋、Cr^6＋浓度增大,慈姑叶绿素含量与根细胞质膜透性先升高后降低;Cd^2＋浓度增大,根和叶的POD活性,叶的SOD活性、丙二醛（MDA）含量及根的超氧阴离子（O2^-）产生速率均是先升后降;根和叶的CAT活性、根的SOD活性、MDA含量和叶的O2^＋产生速率则逐渐升高;而Cr^6＋处理时,MDA含量、根的SOD、CAT、POD活性均随浓度增大而升高,O2^-产生速率和叶的SOD、CAT、POD活性则升高后降低;Cd^2＋和Cr^6＋污染都对慈姑产生毒害,其毒害的效应既有相似性又有差异,同浓度条件下根的受害程度比叶严重．  相似文献   

镉及其络合物在黏土上的吸附行为     

王丹瑞  贾旭  于凌  张凤君  常馨月 《世界地质》2010,29(4):663-667

淋洗剂EDTA 二钠和柠檬酸三钠与镉形成的络合物及镉本身在黏土上的吸附行为研究表明: 上述两种淋洗剂能有效提取表层土中的Cd,形成的络合物在迁移过程中又能较好地被黏土层吸附。黏土对Cd2 +、Cd--EDTA 和Cd--柠檬酸的吸附容量顺序为: Cd--柠檬酸＞ Cd2 + ＞ Cd － EDTA; 3 种形态的吸附过程均以离子交换吸附为主,并在15 min 内完成。黏土对Cd2 + 和Cd － 柠檬酸的吸附容量随溶液初始pH 的升高而增大,对Cd--EDTA 的吸附容量随pH 升高略有降低。  相似文献   

水稻土中Hg,Cd,Pb和As的空间变异性特征及相关影响因素探讨--以四川孝泉地区为例   总被引：3，自引：0，他引：3       下载免费PDF全文

刘爱华  杨忠芳  张本仁  汤奇峰  马晓可  金立新 《第四纪研究》2005,25(3):396-403

以四川孝泉地区水稻土为研究对象,利用地质统计学方法,系统地研究了水稻土中Hg,Cd,Pb和As含量的空间分布特征和空间变异性特征,就可能的影响因素进行讨论并得出结果:1)孝泉地区水稻土中Hg,Pb和As含量的空间自相关尺度分别为10.4km,3.8km和5.1km,且为中等程度相关;Cd在所研究的尺度上不表现明显的空间相关性。2)城镇生活、生产废弃物无序排放,铁路、公路运输,农业施肥、灌溉等因素对孝泉地区水稻土中Hg,Cd,Pb和As含量的空间变异性均有不同程度的影响。3)运用地质统计学方法处理多目标地球化学调查数据能有效地提取地球化学变量的空间结构信息并能在不同尺度上检验取样网度的合理性。  相似文献   

陕西潼关金矿区土壤Pb和Cd生物有效性的影响因素及其意义   总被引：2，自引：1，他引：1  

张江华  王葵颖  李皓  陈华清  柯海玲  刘瑞平  赵阿宁 《地质通报》2014,33(8):1188-1195

土壤中重金属形态与其赋存条件之间的关系是评估土壤重金属风险的关键问题。以受金矿开发影响的土壤中Pb、Cd为研究对象,采用动力学方程分析了土壤有机质、粘粒、pH、Eh等对Pb、Cd生物有效性的影响。结果表明,研究区影响Pb、Cd生物有效性的主要因素有土壤有机质、pH及Eh;有机质与土壤中的Pb、Cd总量呈现正相关性;但当有机质含量增加时,Pb、Cd的水溶态和离子交换态含量反而降低;土壤粘粒对Pb、Cd生物有效性的影响不甚明显;虽然较低的土壤pH值会加剧重金属离子的活性,增强其生物有效性,但过高的pH值又会提高Cd碳酸盐态、铁锰氧化态的含量;Pb、Cd生物有效性随着土壤氧化—还原电位的降低而减弱。研究发现,对于Pb、Cd污染的土壤,通过增施有机肥可提高农产品的安全性;保持土壤处于弱酸—弱碱有利于降低农产品风险;在农作物成熟期实施淹水灌溉,降低土壤氧化—还原电位,可抑制Pb、Cd在籽粒中的累积。  相似文献