用绿粉茶作吸着剂富集分离水中各类重金属的方法

本文探讨了以绿茶富集分离水中各类重金属的方法及其有效性的问题。在稀硫酸溶液中用甲醛处理绿粉条,然后取0.5g经甲醛处理过的茶添加到100ml含有Ag~+、Cd~(2+)、Co~(2+)、Cu~(2+)、Fe~(3+)、Mn~(2+)、Ni~(2+)、Pb~(2+)和Zn~(2+)等九     

1耐铬(Ⅵ)沙雷氏菌S2的筛选及铬(Ⅵ)还原特性研究

目的筛选和鉴定能够耐高浓度Cr(Ⅵ)的菌株,并探究该菌株Cr(Ⅵ)还原特性对于微生物治理铬污染环境的意义。方法通过驯化、筛选后得到高耐铬菌株,研究菌落形态、生化特性及16S rDNA比对鉴定细菌种属;再从Cr(Ⅵ)浓度、温度、pH值、外界常见金属、非金属及有机物等方面研究该菌株的生长特性和除Cr(Ⅵ)特性,并用透射电镜定位菌株中发生Cr(Ⅵ)还原的可能部位。结果筛选并鉴定出沙雷氏菌(Serratia sp.)S2,能在含1 000 mg/L Cr(Ⅵ)的LB肉汤中正常生长;当初始Cr(Ⅵ)浓度为50 mg/L、p H值为7.0、温度为37℃时,S2生长能力及Cr(Ⅵ)还原能力最强;Pb~(2+)、Hg~(2+)、Cd~(2+)、Cu~(2+)能抑制S2生长,而酚和氨基氮能促进S2的生长;透射电镜下观察到含铬黑色颗粒位于菌体中。结论沙雷氏菌S2能耐受高浓度的Cr(Ⅵ),有较好的还原Cr(Ⅵ)能力,初步确定其还原Cr(Ⅵ)的场所在胞内。     

环境中耐锰细菌的筛选鉴定及除锰性能研究

目的从实际污染环境中筛选出耐重金属锰的菌株,研究其耐锰和除锰性能,并进行菌种鉴定,为微生物修复锰污染提供更好选择。方法从潍坊、日照、南京等地区的27份土壤和污水样品中筛选出耐锰、除锰能力较强的细菌,用电感耦合等离子体质谱测试其耐锰性能、除锰离子能力和对其他常见重金属的去除能力,并进行细菌鉴定。结果筛选出的3株细菌(编号为M2、M7a及M9)对1.0 g/L以内的Mn~(2+)去除率大于90%,且可以针对Mn~(2+)浓度较高的样品进行处理;3株细菌处理Mn~(2+)的浓度适宜范围分别为2.5、4.0、3.5 g/L以内(去除率60%),最高耐受Mn~(2+)浓度分别为4.5、8.0、8.0 g/L;3株细菌对Cd~(2+)和Zn~(2+)同样具有较好的耐受性和去除能力。通过16S r DNA测序及Biolog生化鉴定,将菌株M2鉴定为木糖氧化无色杆菌,菌株M7a和M9均为黏质沙雷菌。结论本研究筛选获得的3株细菌除锰能力强、耐锰性能优良,丰富了国内外现有的耐锰除锰菌种库,在微生物修复锰污染领域具有广阔应用前景。     

基于秀丽线虫的5种重金属生物毒性评价

目的评估5种重金属对秀丽线虫的生物毒性效应。方法将L1期秀丽线虫暴露于氯化汞(汞浓度为0、2.5、5.0、10、20、40、50μmol/L)、氯化铅(铅浓度为0、50、75、100、125、150、200μmol/L)、氯化镉(镉浓度为0、300、400、500、600、700、1 000μmol/L)、重铬酸钠(铬浓度为0、50、75、100、200、300、400μmol/L)、砷酸钠(砷浓度为0、50、100、200、300、400、600μmol/L)溶液中,加入E.coli OP50悬液10μl,暴露48 h。采用半数致死浓度(LC_(50))比较5种重金属对线虫生物毒性效应。结果 Hg~(2+)、Pb~(2+)、Cr~(6+)、As~(5+)、Cd~(2+)对秀丽线虫的LC_(50)及其95%CI分别为17.83μmol/L(95%CI=16.15～19.52μmol/L)、124.34μmol/L(95%CI=120.72～127.63μmol/L)、231.79μmol/L(95%CI=186.99～276.68μmol/L)、305.83μmol/L(95%CI=226.17～380.88μmol/L)、558.30μmol/L(95%CI=498.99～609.01μmol/L)。采用评估因子法获得Hg~(2+)、Cr~(6+)、As~(5+)、Pb~(2+)、Cd~(2+)的预测无效应浓度(PNEC)分别为3.60、12.06、22.95、25.67、62.50μg/L。结论 5种重金属对线虫的生物毒性效应依次为Hg~(2+)Pb~(2+)Cr~(6+)As~(5+)Cd~(2+)。     

二阶导数分光光度法同时测定微量的镍、锌和铜

用一般的分光光度法不能同时测定微量的镍(Ni~(2+))、锌(Zn~(2+))和铜(Cu~(2+)),因为这三种离子的光谱带严重重叠,互相干扰,所以必须分离后进行测定。本文介绍用二阶导数分光光度法可同时铡定微量的镍、锌和铜,它是根据Ni~(2+),Zn~(2+)、Cu~(2+)与1-(2-吡啶偶氮)-2-萘酚(PAN)形成络合物,其二阶导数光谱峰明显分离,基线到峰顶的距离与Ni~(2+),Zn~(2+),Cu~(2+)离子浓度呈正比关系。本法操作简单,灵敏,快速,适用于药物分析和环境监测。     

聚L-缬氨酸修饰电极差分脉冲伏安法测定自来水中锌和镉

目的制备聚L-缬氨酸(L-Val))修饰电极,并用于自来水中锌离子和镉离子的快速测定。方法于pH值为5.5的Na_2HPO_4-NaH_2PO_4缓冲液中,用循环伏安法(CV)将L-Val电聚合修饰至玻碳电极(GCE)表面,制得聚L-缬氨酸修饰电极(PL-Val/GCE),并用CV法、电化学阻抗法(ESI)对制备的电极性能进行表征。将PL-Val/GCE作为工作电极,建立了差分脉冲伏安法(DPV)测定水中痕量的Zn~(2+)和Cd~(2+)。结果在最佳的条件下,Zn~(2+)和Cd~(2+)的氧化峰电位分别为-1.184 V和-0.872 V。Zn~(2+)峰电流在(5.0×10~(-9)～2.0×10~(-5))mol/L的浓度与其浓度呈良好线性关系,Cd~(2+)峰电流在(5.0×10~(-9)～1.5×10~(-7))mol/L和(2.5×10~(-7)～1.0×10~(-5))mol/L的浓度与其浓度呈良好线性关系。Zn~(2+)和Cd~(2+)的检测限均为2.0×10~(-9) mol/L。Zn~(2+)和Cd~(2+)在自来水样品中的平均回收率在90.0%～105.8%;连续平行测定3次RSD均4.4%。结论该方法灵敏度高、检测速度快、准确性高,适用于自来水中的Zn~(2+)和Cd~(2+)的测定。     

饮料中锑的氢化物发生-原子荧光测定法

目的探讨饮料中锑的氢化物发生-原子荧光测定法。方法以 L-半胱氨酸为预还原剂,应用氢化物发生-原子荧光光谱法测定锑含量。结果在该方法的最佳条件(1%HCl,2%KBH_4,2%L-半胱氨酸)下,40 mg/L 的 Fe~(3 )、Pb~(2 )、50mg/L 的 Cu~(2 )、Mn~(2 )、Zn~(2 )、Sn~(2 )、Se~(4 )、Hg~ 、As~(3 )、Bi_(3 )以及10 mg/L 的 Cr~(6 )、Cd~(2 )对锑测定均无干扰。在0～60.0μg/L 范围内,该方法所得线性回归方程为:y=65.1x 13.2,相关系数(r)为0.999 9,检出限为0.35 μg/L,平均回收率为89.50%～103.75%,RSD 分别为1.51%和1.22%。与国家标准法比较,差异均无统计学意义(P>0.05)。结论该方法具有试剂用量少,污染小,检出限低,灵敏度高,重现性好,线性范围宽及干扰少等特点,适用于饮料中锑含量的检测。     

常见非致病菌对无机砷抵抗作用

目的 初步探讨几种常见非致病菌对无机砷(As3 )的抵抗作用.方法 采用在培养基中加入不同浓度亚砷酸钠的方法研究各菌株对砷的耐受性,并在显微镜下进行细菌量计数,采用超低温捕获原子吸收分光光度仪测定菌体中砷含量.结果 绿脓杆菌可耐受100 mg/L的As3 浓度,大肠埃希菌、白色葡萄球菌、蜡样芽孢杆菌和酵母菌均可耐受1 000 mg/L的As3 浓度;大肠埃希菌对As3 有一定的富集能力.结论 实验所用各菌株均对As3 具有一定的抵抗作用,对As3 的转化还需进一步研究.     

铜和土霉素复合暴露对玉米幼苗生长发育的影响

目的探讨铜和土霉素复合暴露对玉米幼苗生长发育的影响。方法观察铜(Cu~(2+))和土霉素(OTC)单一暴露及Cu~(2+)+OTC复合暴露对其发芽、总根长、叶片抗氧化酶和丙二醛含量的影响。结果 OTC、Cu~(2+)单一暴露、Cu~(2+)+OTC复合暴露对玉米种子发芽率的影响无统计学意义(P0.05)。与对照组相比,Cu~(2+)(20、30 mg/L)单一暴露组总根长在8 h显著减低,随着生长时间的延续,Cu~(2+)(20、30和40 mg/L)单一暴露组总根长在96 h明显减低,差异有统计学意义(P0.05);与对照组相比,Cu~(2+)+OTC(30、40 mg/L)组处理8 h玉米幼苗根系总根长缩短,随着玉米幼苗的生长,在24 h~96 h Cu~(2+)+OTC(10~40 mg/L)复合暴露组玉米幼苗根系总根长缩短,差异有统计学意义(P0.05)。Cu~(2+)+OTC复合暴露与Cu~(2+)、OTC单一暴露对玉米幼苗叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)的活力没有明显影响(P0.05)。与对照组相比,40 mg/L Cu~(2+)单一暴露组MDA含量的升高,差异有统计学意义(P0.05);而OTC单一暴露组玉米幼苗叶片中MDA含量无明显变化(P0.05);Cu~(2+)+OTC(20~40 mg/L)复合暴露组8~120 h MDA含量增加,差异有统计学意义(P0.05)。结论 Cu~(2+)单一暴露和Cu~(2+)+OTC复合暴露对玉米幼苗总根长有一定的抑制作用,且叶片组织发生氧化损伤。     

细菌发光传感器对污染物急性毒性快速检测的研究

目的 研究建立一种快速、灵敏、简便的测定污染物急性毒性的生物传感器。方法 利用明亮发光杆菌的细胞发光作为毒性的判断指标,将细胞固定化技术、生物传感器技术与发光细菌毒性测试技术有机结合起来,构建了一种细菌发光传感器。结果 在pH=7.0,温度20℃,3.0％ NaCl底液条件下,固定化菌膜发光强度达2～4nw,稳定发光时间60～80min,毒性测试结果EC_(50)(EC_(50):菌膜发光强度抑制50％所需受试物的浓度)如下:Hg~(2+)0.14mg/L,Cu~(2+)20.3mg/L,Zn~(2+)120mg/L,苯酚48.9mg/L,乐果5.26mg/L,乙醛210mg/L,与哺乳动物毒性试验的LD_(50)(大鼠,经口)具有相关性:Log LD_(50)=1.226+0.91 Log EC_(50),r=0.95。结论 不同毒物之间对细菌发光反应的抑制速率有差异。     

Toxicity of heavy metals using sperm cell and embryo toxicity bioassays with Paracentrotus lividus (Echinodermata: Echinoidea): comparisons with exposure concentrations in the Lagoon of Venice,Italy

Sperm cell and embryo toxicity tests using the Mediterranean sea urchin Paracentrotus lividus Lmk were performed to assess the toxicity of As3+, Cd2+, Cr3+, Ni2+, Pb2+, Cu2+, Zn2+, and Hg2+. The aim of this study was to improve information about the comparative sensitivity of sea urchin bioassays to the heavy metals, which are an important cause of contamination in the ecosystem of the Lagoon of Venice. Considering the data in mM/L, the order of toxicity is Hg2+ > Cu2+ > Zn2+ > As3+ > or = Cr3+ > or = Cd2+ > or = Pb2+ > or = Ni2+ for the sperm cell test and Hg2+ > or = Pb2+ > Cu2+ > Zn2+ > Cd2+ > Ni2+ > As3+ > or = Cr3+ for the embryo test. New toxicity data for metals expressed as median effective concentration (EC50) and no-observed-effect concentration (NOEC) are reported for the Mediterranean species. Accurate observations of embryotoxic effects at increasing metal concentrations were done, detecting some different behaviors in metal toxicity. Toxicity data compared with water column and pore-water concentrations recorded in the Lagoon of Venice (Italy) demonstrate the potential ability of bioassays using sea urchin to detect important contaminants in this ecosystem.     

Exposure of human proximal tubule cells to cd2+, zn2+, and Cu2+ induces metallothionein protein accumulation but not metallothionein isoform 2 mRNA.

The organization of the human metallothionein (MT) gene family is more complex than the commonly used mouse and rat models. The human MTs are encoded by a family of genes consisting of 10 functional and 7 nonfunctional MT isoforms. One objective of this study was to determine if the accumulation of MT protein in cultures of human proximal tubule (HPT) cells exposed to metals is similar to that expected from the knowledge base obtained from rodent models. To accomplish this objective, HPT cells were exposed to both lethal and sublethal concentrations of Cd2+, Zn2+, Cu2+, Ag2+, Hg2+, and Pb2+ and MT protein levels were determined. The results were in general agreement with animal model studies, although there were some exceptions, mainly in areas where the animal model database was limited. In clear agreement with animal models, Cd2+, Zn2+, and Cu2+ were demonstrated to be potent inducers of MT protein accumulation. In contrast to the similarity in MT protein expression, we obtained evidence that the human renal MT-2 gene has a unique pattern of regulation compared to both animal models and human-derived cell cultures. In the present study, we determined that MT-2A mRNA was not induced by exposure of HPT cells to Cd2+ or the other metals, a finding in contrast to studies in both animal models and other human cell culture systems in which a high level of MT-2 mRNA induction occurs upon exposure to Cd2+ or Zn2+. While MT protein expression may be similar between humans and animal models, this finding provides initial evidence that regulation of the genes underlying MT protein expression may be divergent between species.     

公路旁土壤中重金属污染分布及潜在生态危害的研究

[目的]研究公路旁土壤中重金属污染的分布及潜在生态危害。[方法]以319国道龙岩市新罗区路段为研究区,对耕作土采样,用原子吸收光谱法和分光光度法分析土壤中重金属Cd、Pb、Cu、Zn和Cr含量,并与对照区比较,同时采用Lars Hakanson指数法评价重金属的潜在生态危害。[结果]研究区表层土壤cd[(1.48±0.60)mg/kg]、Pb[(160.17±55.99)mg/kg]、cu[(38.44±12.16)mg/kg]、Zn[(80.35±6.60)mg/kg]、Cr[(79.50±23.58)mg/kg]含量显著高于对照区(P<0.001),Cd和Pb为重度污染(100％),Cu和Cr为轻微污染(分别占监测点位的55.8％和35.3％);土壤对重金属元素的吸收及污染程度:Pb>Cd>Cu>Cr>zn。潜在生态危害综合指数为253.0,主要污染为Cd,达到很强的生态危害,其次是Pb、Cu、Cr和Zn,均为轻微生态危害;潜在生态危害地带自公路起向其两侧扩散范围约为150 m。[结论]公路旁土壤中重金属以Cd、Pb污染为主,属于中等生态危害,污染物主要来源于机动车辆燃料和轮胎中所含微量重金属成分。     

Divalent metal inhibition of non-haem iron uptake across the rat duodenal brush border membrane

Duodenal Fe2+ uptake is essential to body Fe2+ homeostasis, but the interaction of metals with the uptake process remains unclear. The present study compared the effects of four essential trace metals (Mn2+, Zn2+, Co2+ and Ni2+) with two toxic metals (Pb2+ and Cd2+) on Fe2+ uptake across the brush border membrane of villus-attached duodenal enterocytes. Everted rat duodenum was exposed to buffer containing 0.2 mm-59Fe2+-ascorbate with or without the competing metal (2 mm) and the tissue was then processed for autoradiography allowing Fe2+ uptake to be determined at specific crypt-villus regions. The quantification method ensured that uptake by cells, rather than Fe2+ binding to the tissue surface, was measured. Fe2+ uptake was significantly inhibited by Cd2+ in upper villus enterocytes only and Pb2+ was without effect on Fe2+ uptake. The inhibition by Cd2+ was not due to general cell damage as judged by the release of lactate dehydrogenase from tissue into incubation fluid. Essential divalent trace metals reduced uptake significantly along the whole length of the crypt-villus axis. Cd2+ uptake, measured separately, took place at all regions of the villus-crypt axis, highest uptake being into crypt enterocytes. The very different uptake profiles for Cd2+ and Fe2+ suggests that the divalent metal transporter 1 is not the principal transporter of Cd2+. The addition of Fe2+ to incubation buffer inhibited Cd2+ uptake by both crypt and villus enterocytes. The possibility that the inhibitory actions of Fe2+ and Cd2+ on the uptakes of Cd2+ and Fe2+ respectively can be explained by a non-competitive action or the involvement of an additional metal transporter is discussed.     

Differences in Concentration of Heavy Metals Between Native and Transplanted Plagiothecium denticulatum: A Case Study of Soils Contaminated by Oil Well Exudates in South East Poland

For a period of 60 days, the terrestrial moss Plagiothecium denticulatum was transplanted from a clean control site to a soil contaminated with crude oil exudates (Krosno, South East Poland). Native P. denticulatum growing on this contaminated soil was collected during the same period. Concentrations of the metals Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn as well as the macroelements N, P, K, Ca, Mg, and S were determined in P. denticulatum and in soils from the contaminated and control sites. Contaminated soil was the main contributor of Ba, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn to native and transplanted P. denticulatum. Other sources of contamination apart from the soil existed for Cd and Cu. Transplanted P. denticulatum accumulated significantly more Al, Cr, Cu, Ni, Pb, and Zn, and native P. denticulatum accumulated significantly more N, P, K, and Ca. Higher levels of N, P, K, and Ca in native P. denticulatum indicates a possible mechanism to prevent the loss of these elements as observed in the transplanted P. denticulatum.     

Low metal bioavailability in a contaminated urban site

Bioavailability of Cd, Cu, Ni, Pb, and Zn in a metal-enriched railway yard in Montréal, Québec, Canada was assessed using metal speciation, plant uptake, and microbial assays. Metal speciation of extracted soil solutions was estimated using the Windmere Humic Aqueous Model. In soil solutions, free Cd, Ni, and Zn ions represented as much as 80%, 72%, and 62%, respectively, of the total dissolved metals. Copper and Pb were strongly bound by dissolved organic matter, and metal-fulvic acid complexes represented as much as 99% of the total dissolved metals. Three field-collected plant species (dandelion, bladder campion, and chicory) varied in their tendency to accumulate metals in either their leaves or roots. Chicory grown in the greenhouse had significantly higher metal bioconcentration factors than wild chicory. Although the site studied is considered to be contaminated, no metal pool, such as free ions or dissolved or total soil metals, consistently predicted metal uptake by potted chicory. Regression analysis revealed that soil total metal concentrations could adequately predict tissue accumulations of Cd, Ni, Pb, and Zn in bladder campion but only Cd and Zn in dandelion. Data from microbial assays also showed that the soil respiration was not affected by the metal contamination, but that nitrification was inhibited for the most contaminated soils. These results indicate that the metal bioavailability in the railway yard is low, but they also suggest that nitrogen cycling may be affected.     

Effect of Cd or Pb Addition to Cu-Contaminated Soil on Tissue Cu Accumulation in the Earthworm,Dendrobaena veneta

Generally, soil heavy metal contamination consists of a mixture of heavy metals. Soil chemical properties and interaction with other pollutants in soil affect the external heavy metal bioavailability. Moreover, interaction with other pollutants accumulated in organisms may change the toxicity of each pollutant. Therefore, the hypotheses was tested that addition of Cd or Pb to Cu-contaminated soil would lead to an increase in tissue Cu accumulation in the earthworm,Dendrobaena veneta,caused by (i) induction of metallothionein by Cd, or (ii) an increase in Cu concentration in soil solution due to the exchange of adsorbed Cu for Pb. Tissue heavy metal concentrations were determined after exposure in contaminated soils for 3 or 21 days. Considerable amounts of Cu, Cd, and Pb were accumulated, indicating that these heavy metals were available for uptake byD. veneta.Both Cd and Pb, however, did not significantly affect tissue Cu accumulation.     

Bioaccumulation of heavy metals in mullet (Mugil cephalus) and oyster (Crassostrea madrasensis) from Pulicat lake, south east coast of India

The accumulation of six heavy metals (Cr, Cd, Cu, Zn, Pb and Ni) in sediment, water and in tissue parts of Mugil cephalus and Crassostrea madrasensis was studied in two locations of Pulicat lake, Southeast coast of India, which receives considerable quantity of effluents from industries located in North Chennai coastal region. The results reveal that the metal concentration in water is decreasing in the following order of Zn > Ni > Cu > Cr > Pb > Cd both in lake and barmouth and highest concentration was observed for Zn (32.5 μg L(-1) in lake and 25.2 μg L(-1) in bar mouth). Metals were highly concentrated in sediments when compared to water and biota. Metals abundance in sediments has following sequential order of Cr > Ni > Zn > Cu > Pb > Cd and the accumulation pattern in barmouth showed minor variation indicating the following pattern of Zn > Ni > Cr > Cu > Pb > Cd. The geoaccumulation index (I(geo)) for Pulicat lake sediments indicate that the sediments are extremely contaminated with Cd and moderately contaminated with Cu and Ni. Bioaccumulation of heavy metals in Mugil cephalus and Crassostrea madrasensis showed marked differences in the accumulation patterns. It is observed that Zn, Cu and Pb are accumulated in elevated concentrations in various parts of the fish and oyster when compared with other metals.     

Metal distribution and metallothionein induction after cadmium exposure in the terrestrial snail Helix aspersa (Gastropoda, Pulmonata)

The aim of the present work was to study the effect of Cd2+ exposure on metallothionein (MT) induction and on the distribution of metals (Cd, Cu, and Zn) in the terrestrial pulmonate Helix aspersa. In particular, the soluble and nonsoluble pools of the accumulated metals and their tissue distribution in uncontaminated and contaminated edible snails were investigated after a two-week exposure to Cd2+. In the soluble cytosolic pool of the midgut gland of H. aspersa, three metal-specific putative MT isoforms were separated following a fractionation protocol with diethylaminoethyl cellulose, size-exclusion chromatography, ultrafiltration, and reversed-phase high-performance liquid chromatography (RP-HPLC). Interestingly, one of the above isoforms seems to bind both Cd and Cu, which may in addition mobilize, after induction by Cd2+, some of the intracellular Cu and, thus, perhaps increase the Cu pool in the cytosolic fraction. The cDNA and its translated amino acid sequence of a Cd2+-binding MT isoform from the snail midgut gland was characterized and attributed to one of the putative MT isoforms obtained by RP-HPLC. The amino acid sequence of this Cd-MT isoform of H. aspersa differed from similar sequences described in other terrestrial pulmonates, such as Helix pomatia or Arianta arbustorum, by only a few amino acids (n = 4 and 8, respectively). That the identified Cd-MT from H. aspersa is inducible by Cd2+ also was shown, chromatographic evidence aside, by a specific polymerase chain reaction protocol on a cDNA basis, which included a noninducible housekeeping gene as a control.