Physiology and Ultrastructure of Azolla imbricata as Affected by Hg 2+ and Cd 2+ Toxicity

The toxic effects of different gradient concentrations of Hg2+ and Cd2+ on chlorophyll content, chlorophyll a/b value, photosynthetic O-2 evolution, respiration rate, anti-oxidase system (superoxide dismulase (SOD), catalase (CAT), peroxidase (POD)) and ultrastructure of the cells of Azolla imbricata (Roxb.) Nakai were studied. The results showed that with Hg2+ and Cd2+ increase, chlorophyll content and chlorophyll a/b value, photosynthetic O-2 evolution decreased drastically; respiration rate peaked at 2 mg/L pollutant and declined afterwards. The activities of SOD, CAT and POD increased first and decreased afterwards except the activity of POD, which decreased with the increasing of Cd2+ concentration. Ultrastructural observation showed that the extent of ultrastructural damage was much more serious with higher pollutant concentration and longer time of stress. This resulted in swelling of chloroplast, disruption and disappearance of chloroplast membrane and disintegration of chloroplasts; swelling of cristae of mitochondria, deformation and vacuolization of mitochondria; condensation of chromatin in nucleus, dispersion of nucleolus and disruption of nuclear membrane. The experimental results showed: (1) Hg2+ and Cd2+ pollution not only destroyed physiological activities, but also caused irreversible damage to its ultrastructure, thus leading the cells to death; (2) With increase in the stress of Hg2+ and Cd2+, ultrastructural damage was related to the changes of plant physiology; (3) The toxic symptoms of plant showed an evident correlation between dose and effect; (4) The toxicity of Cd2+ on A. imbricata is heavier than that of Hg2+ under the same treatment time and concentration. The lethal concentration of Hg2+ to A. imbricata ranged from 3.5 to 4 mg/L, and that of Cd2+ ranged from 3 to 3.5 mg/L. The damage of cell ultrastructure on Anabaena azollae Strasburger was observed. The results indicated that tolerance of Azolla imbricata for Hg2+ and Cd2+ was higher than that of A. imbricata.

Effects of Heavy Metal Ions (Cu^(2+), Pb^(2+) and Cd^(2+)) on DNA Damage of the Gills, Hemocytes and Hepatopancreas of Marine Crab, Charybdis japonica

There are rising concerns about the hazardous effects of heavy metals on the environment. In this study, comet assay and DNA alkaline unwinding assay were conducted on the tissues (gills, hepatopancreas, and hemocytes) of Charybdis japonica in order to illustrate genotoxicity of three heavy metal ions (Cu2+, Pb2+, and Cd2+) on the marine crabs C. japonica. The crabs were exposed to Cu2+ (10, 50, and 100 ?g.L?1), Pb2+ (50, 250, and 500 ?g L?1) and Cd2+ (5, 25, and 50 ?g L?1), and the tissues were sampled at days 0.5, 1, 3, 6, 9, and 15. DNA alkaline unwinding assay was used for testing the DNA single strand break in gills and hepatopancreas and comet assay was employed for testing the DNA damage in hemocytes. The results showed that the DNA damage (F-value) of gills in the crabs exposed to the three heavy metals was decreased gradually during the exposure periods and there was a dose-time response relationship in certain time, suggesting that the levels of DNA single strand break in all the experimental groups increased significantly compared to the controls. Changes of F-value in hepatopancreas of the crabs exposed to the three heavy metals were similar to those in gills except that the peak values were found in the 500 ?g L?1 Pb2+ treatment group at day 3 and the 50 ?g L?1 Cd2+ treatment group at day 9. The ranks of DNA damage in gills and hepatopancreas induced by the three heavy metal ions (50 ?g L?1, day 15) were Cd2+ >Pb2+ >Cu2+ and Pb2+ >Cu2+ >Cd2+. The levels of DNA damage in gills were higher than those in hepatopancreas in the same experimental group. It can be concluded that indices of DNA damage can be used as the potential biomarkers of heavy metal pollution in marine environment.

Effect of Pb and Cd Stress on the Growth of Potato and Its Antioxidase System

With the potato variety Xishu 1 as the test materials, this paper adopted tissue culture to study the effect of Pb and Cd stress with different mass fractions on potato growth and the antioxidase system. The results showed that under the stress of Pb （200 mg/kg） and Cd （20 mg/kg）, growth of potato had no obvious difference with that in control group; under the stress of Pb （ 〉200 mg/kg） and Cd （ 〉20 mg/kg）, potato growth suspended, and its physiological indexes such as dry weight, plant height, root number, root length were inhibited obviously. With the increasing mass fraction of Pb, relative electrical conductivity, MDA and proline of potato leaves showed the tendency of increase, and the results in high mass fraction treatments showed significant difference with those in the control group （P 〈 0.05 ）, CAT, POD and SOD activity of leaves increased greatly with the increasing mass fraction. In the Pb stress treatment （200 mg/kg）, relative electrical conductivity, MDA and proline of potato leaves showed no obvious difference with those in the control group, and the results in high mass fraction treatments were significantly higher than those in the control group （ P 〈 O. 05 ）, CAT and SOD activity increased greatly with the increasing mass fraction （ P 〈 0.05 ）. Under the stress of Pb and Cd, synthesis of soluble protein in potato leaves was strongly inhibited. The results showed that potato was tolerant to Pb and Cd of lower mass fraction, and damage of potato caused by Pb and Cd stress could be relieved by improving activity of antioxidase and reducing peroxidation of membrane lipid, and the tolerance reduced with the increase of stress.

GLDA及其组合试剂对土壤中As、Cd、Cu和Pb的提取能力和机制

以重金属复合污染土壤为研究对象,将谷氨酸二乙酸四钠(GLDA)和其他生物可降解络合剂进行组合,研究了单一和组合试剂对土壤中不同重金属的提取效率和影响机制。结果表明:随着试剂与土壤重金属摩尔比的增加,重金属的提取率逐渐增加,最优摩尔比为5∶1;草酸(OA)对As、柠檬酸(CA)对Cu的提取能力高于乙二胺四乙酸二钠(EDTA)对As和Cu的提取能力;GLDA在偏酸的条件下对各种重金属的提取能力均较高;通过不同试剂的组合,GLDA和OA在摩尔比为1∶1时对土壤中As、Cu和Pb的提取能力最强,分别为52.4%、75.0%和89.8%,各重金属元素提取能力顺序为Pb>Cu≈Cd>As。而GLDA和CA在摩尔比为5∶1时对土壤中Cd的提取能力最强,为95.7%。提取前后的土壤重金属形态分级表明,GLDA+OA(1∶1)组合试剂降低了绝大多数形态的重金属含量,减少了易迁移和易被生物吸收的弱结合态重金属含量。

Compound pollution of Cd,Pb,Cu,Zn,and As on lowland rice

Cd,Pb,Cu,Zn,and As are typical pollutantsoriginated from Pb-Zn mine,smelting wastewater discharge/irrigation and gas emission,and they were distributed widely in China.Westudied the compound pollution of Cd,Pb,Cu,Zn,and As on rice. Pot culture and field plots test were bothused in the experiment.The treatments were:1)low dose:Cd 0.5,Pb 100,Cu 33,Zn 66,and As 10mg·kg;2)high dose:Cd 1.5,Pb 300,Cu 100,Zn 200,and As 30mg·kg,and 3)CK:no heavy metal was applied.Soil tested was meadow burozen(pH6.3-6.7)and the dosage of heavy metal added to the soilwas close to the soil environmental standard.Results were as follows:

叶面阻控剂对大白菜Cu、Pb、Cd、As含量及产量的影响

土壤重金属污染已成为威胁农产品安全和人类健康的重要问题。为了验证喷施叶面阻控剂降低As-Cu复合污染土壤上大白菜重金属铜(Cu)、铅(Pb)、镉(Cd)、砷(As)的污染效应,在弥勒市选取有代表性的农田,通过田间试验研究了硅肥、铁肥、锌肥、硒肥对As-Cu复合污染土壤上的大白菜Cu,Pb,Cd,As含量及大白菜产量的影响。结果表明,与对照相比,喷施叶面阻控剂均有效降低了大白菜可食用部位Cu、Pb、Cd、As含量,降幅分别为13.32%~36.15%、25.31%~52.39%、14.75%~29.27%、33.55%~45.68%。喷施不同叶面阻控剂有效增加了大白菜产量,增幅为0.10%~3.20%,其中以喷施硅肥处理的白菜产量最高。综合不同阻控剂降低大白菜可食用部位Cu、Pb、Cd、As含量及对大白菜的增产效应,在本试验条件下,在以硅肥的喷施效果最佳。

Adsorption of Pb, Cd to Fe, Mn oxides in natural freshwater surface coatings developed in different seasons

Metal oxides(Fe, Mn oxides) in natural surface coatings(biofilms and associated minerals) are believed to play a significant role in the fate and transport of trace metal in aquatic environments. Seasonal variation of Fe, Mn oxides and organic materials in surface coatings, which were developed periodically on glass slides in Nanhu Lake, Jilin Province, China over the time frame of three seasons, was investigated in order to understand the influence of metal oxides on Pb and Cd adsorption to heterogeneous surface coating materials(biofilm). Pb and Cd adsorption was measured under controlled laboratory conditions(mineral salts solution with defined speciation, ionic strength 0 05 mol/L, 25℃ and pH 6 0). The classical Langmuir adsorption isotherm was applied to estimate equilibrium coefficients of Pb and Cd adsorption to the surface coatings. In general, components in the surface coatings varied greatly with seasons altering and obtained higher concentrations in summer while the content of iron oxides always exceeded that of manganese oxides. Correlation analyses between the maximum adsorption of Pb and Cd and components in the surface coatings developed periodically indicated that Pb phase association with Mn oxides and Cd phase association with Fe oxides as well as Mn oxides were statistically significant. Effect of Mn oxides on Cd adsorption was confirmed in view of its higher content in the surface coatings. The importance of ferromanganese oxides for Pb and Cd adsorption to the natural surface coatings developed in different seasons was evidenced.

应用ICP-MS、AFS、GF-AAS测定食品中As、Cd、Hg、Pb方法的对比研究

应用ICP-MS法测定食品中的As、Cd、Hg、Pb,AFS法测定As、Hg,GF-AAS法测定Cd、Pb,并对3种测定方法进行对比研究。采用微波消解法作为ICP-MS法的样品前处理方法,湿式消解法作为AFS、GF-AAS法的前处理方法。通过优化消解条件,优化ICP-MS、AFS及GF-AAS仪器测定工作条件,选择适宜内标元素、EPA200.8标准干扰校正方程、硫脲-抗坏血酸掩蔽剂、硝酸镁-硝酸钯混合基体改进剂等办法,利用小麦粉(GBW08503b)和大米粉(GBW10010)国家标准物质验证各方法的准确度与可靠性。测定值均在标准值允许范围内,食品试样比对测定结果相对偏差均小于20%。ICP-MS法线性动态范围宽,不必稀释样品,适合批量样品多元素同时分析,但仪器昂贵、实验成本相对较高;AFS、GF-AAS法是单一元素分析,保证了测定结果准确、可靠,但由于线性范围窄,部分样品需要稀释,分析周期较长。

常压湿式消解/常压微波消解-原子光谱法测定近海海洋生物体中Cu、Pb、Cd与Hg、As

采用常压湿式消解、常压微波消解两种方法处理近海海洋生物体,以石墨炉原子吸收法测定Cu、Pb、Cd和氢化物发生原子荧光法同时测定Hg、As。实验表明,以常压湿式消解法处理生物体,其Cu、Pb、Cd回收率分别为92%、103%、105%,而Hg、As的回收率分别是52%、58%。以常压微波消解法处理生物体,其Cu、Cd、Hg、As回收率分别为86%、94%、112%、94%,但用于Pb的测定,其回收率严重偏低。常压湿式消解、常压微波消解分别被用于海洋生物体样品中Cu、Pb、Cd和Hg、As的测定,有较好的测定结果。

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

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。

朱鹮羽毛中Ca,Mg,Pb,Cd,As和Hg六种元素测定

微量元素参与朱鹮体内的许多重要的生命过程,通过了解微量元素含量与朱鹮生长过程及生存环境有重要的联系,也有一些相关报道。文章用ICP和HG-AAS测定我国的朱鹮羽毛中营养性元素、有害元素Ca,Mg,Pb,Cd,As和Hg含量。结果表明,此方法简便、可靠,具有良好的精确度和准确性。通过较长时间对朱鹮羽毛中元素含量的跟踪研究,尤其对有害性元素含量的数据收集、整理和相关性研究,对于改善朱鹮的正常生长繁殖、发育以及生存环境状况是有价值的。

农产品中Zn、Cu、Fe、Pb、Cd、Cr、Hg、As的快速测定

建立了微波消解法一次前处理,电感耦合等离子体发射光谱(ICP-AES)法、石墨炉原子吸收光谱(GF-AAS)法和氢化物-原子荧光光谱(HG-AFS)法相结合联合快速测定农产品中Zn、Cu、Fe、Pb、Cd、Cr、As、Hg等重金属元素的方法。ICP-AES法采用基体匹配法消除对Zn、Cu、Fe的干扰,GF-AAS法采用氘等扣背景和加入机体改进剂消除测定Pb、Cd、Cr的干扰,HG-AFS法采用加入硫脲和抗坏血酸消除同时测定As和Hg的干扰。该方法对7种元素的检出限分别为0.009,0.00024,0.0016,0.001,0.0001,0.001,0.0005,0.00004mg/L,RSD为2.2%～4.9%,白菜样品的回收率为95%～112%。

ICP-MS测定化肥中有害元素Cr、Cd、As、Pb、Hg的新方法

采用电感耦合等离子体质谱法测定化肥中微量Cr、Cd、As、Pb、Hg元素。样品经微波消解和敞开酸溶,滴加5～8滴2%高锰酸钾氧化,低温水浴加热蒸至近干,加甲醇2 mL溶剂化,用水定容至100 mL,进行测定。方法标准加入回收率为67%～115%,RSD小于15%,误差完全符合GB18877-2002的规定要求,方法简便快速。

微波消解—原子吸收/原子荧光光度法测定活性污泥中的Cd、Pb、Ni、Cu、Zn、Cr、K、As、Hg

通过实验,建立了活性污泥中金属和重金属的测定方法。活性污泥样品经硝酸—氢氟酸或硝酸—高氯酸微波消解处理后,Pb、Ni、Cu、Zn、Cr、K选用火焰原子吸收分光光度法测定,Cd用石墨炉原子吸收分光光度法测定,As、Hg用原子荧光光度法测定。该方法操作简单,结果准确,重现性好。样品加标回收率为93%-108%,相对标准偏差〈5%。

试论有害微量元素As、Pb、Cd、Hg对生态系统的毒害作用

本文论述了有害微量元素Cd、Pb、As、Hg的物理、化学、病理学、生物无机化学及地球化学性质,探讨了这四种元素在生态系统中的变迁,对动植物的毒害作用机理及与人的健康的关系.并提出应当重视微观生态学的研究.

吉林黑土中Cd、Pb、As的空间分布及潜在生态风险

研究了吉林省黑土区耕层土壤（0～20cm）中Cd、Pb、As含量的分布特征及其潜在生态风险．结果表明、煤矿区周围、公路旁和城郊为农田黑土Cd、Pb、As的高含量分布区，煤矿区周围土壤Cd、Pb、As均具有明显的累积效应，公路旁和城郊的土壤外源Pb进入量较大．采用Muller地累积指数法和Hakanson潜在生态危害指数法得出的潜在生态风险评价结果表明，煤矿区土壤Cd具有很高的潜在生态风险，As具有一般风险；各采样区的Pb含量均呈现一般风险．总体而言，煤矿区土壤具有一般潜在风险，而公路旁和城郊土壤均具有低潜在生态风险．

磷基及铁基钝化剂对Pb、Cd、As复合污染土壤的修复效果及其工艺条件优化

通过DTPA和Na HCO3浸提方法评价磷基、铁基钝化剂对Pb、Cd、As复合污染土壤的钝化修复效果。结果表明,磷基钝化剂中磷酸二氢钙对有效态Pb、Cd固定效果较好,35 d后其去除率分别为61%、38%;铁基钝化剂中以硫酸高铁对有效态As固定效果最好,28d后其去除率达74.6%。工艺条件优化结果表明,随磷酸二氢钙用量增加,土壤中有效态Pb、Cd含量明显下降;随硫酸高铁用量增加,对有效态As的固定效果明显增加,当硫酸高铁添加量为土壤中As总物质的量的3.06倍时,28 d后土壤中有效态As的去除率高达74.5%。土壤水分含量在最大田间持水量的60%~80%时,对有效态Pb固定影响不大,但均略高于最大田间持水量30%~50%时的Pb去除率;土壤水分含量在最大田间持水量的60%~80%时,有效态Cd固定效果较好。当磷酸二氢钙用量为土壤中Pb、Cd总物质的量的10倍,土壤水分含量为最大田间持水量的60%时,21 d后有效态Pb、Cd去除率分别达到93%和39%。铁基与磷基钝化剂复配可以同时固定土壤中的Pb、Cd、As。当Fe3＋与PO3-4物质的量的比为7.2∶1时,7 d后土壤有效态Pb、Cd、As去除率分别为99%、41%、69%。

吉林省农田黑土中Cd、Pb、As含量的空间分布特征

利用地统计学方法研究了吉林省黑土区耕层土壤（0～20cm）中Cd、Pb、As含量的空间结构及其分布特征．结果表明，研究区土壤Pb含量属中等程度的空间相关，而Cd、As含量属空间弱相关．3种元素含量的空间变异主要受人为的随机性因素的影响．利用半方差函数的分析结果经普通克立格插值得到了3种元素含量的空间分布图．结果显示，在空间分布上，受不同污染源的影响，土壤Cd、Pb、As含量表现出不同的分布特征．土壤Cd含量较高的地区主要分布于煤矿区周围；土壤Pb含量高的样点主要分布于城郊及公路两侧；煤矿区周围及城郊农田土壤中As含量相对较高．

Cd、Pb、Ni、As单一污染对油麦菜叶绿素含量和抗氧化酶系统的影响

研究了Cd、Pb、Ni、As单一污染对油麦菜叶绿素含量和抗氧化酶系统的影响,结果表明油麦菜叶绿素含量低于对照,并且随着Cd、Pb、Ni、As处理浓度的增加呈先升后降的趋势;油麦菜抗氧化酶系统所受影响因重金属污染种类不同而不同,其中SOD的活性随着Cd、Pb单一污染浓度的增加呈下降趋势,而随着As、Ni污染浓度的增加呈先升后降的趋势;CAT和POD的活性随着As污染浓度的增加呈上升趋势,而随着Cd、Pb、Ni污染浓度的增加呈先升后降的趋势。

微波消解/ICP-MS同时测定扶芳藤中的Cu、Pb、As、Cd

用硝酸进行消解,电感耦合等离子体质谱法（ICP-MS）同时测定扶芳藤样品中Cu、Pb、As、Cd。用国家一级标准物质茶叶（GBW 10016）和标准物质茶叶（GBW 8505）评价了方法的准确性。结果表明：方法对试样中各元素测定的相对标准偏差范围为3.35%-7.59%,回收率在87.6%-101.4%。该法简便、快速、灵敏,适合于扶芳藤中Cu、Pb、As、Cd的测定。