水热法改性粉煤灰去除矿山酸性废水中金属离子

矿山酸性废水污染是由开采矿山和废弃矿山的所产生的重要环境问题。本文利用廉价的粉煤灰通过水热法改性制备了沸石吸附剂,研究了不同pH值、接触时间和吸附剂加入量条件下,矿山废水中的重金属离子去除效果。结果表明：pH值是影响重金属离子去除的重要因素,pH值在为7时,其对Pb²⁺、Zn²⁺、Cu²⁺去除率分别为100%、95.2%和95.8%;吸附剂对Cu²⁺的去除主要是由吸附和沉淀共同作用完成的,而Zn²⁺和Pb²⁺的去除主要依靠吸附作用。随着吸附剂加入量的增加,Pb²⁺、Zn²⁺、Cu²⁺的吸附率也随之增加,其最优加入量分别为20、25和30 g·L^-1。当Pb²⁺、Zn²⁺、Cu²⁺的吸附时间分别为20、40和50 min时,其去除率可分别可达94.2%、95.2%和98.2%。此外,还讨论了复合离子相互间强化和抑制作用。当3种离子同时存在时,其相互间的强化作用并不明显,但会呈现较显著的抑制作用。     

重金属递进胁迫对黑麦草初期生长的影响

通过研究Cu²⁺、Zn²⁺、Cd²⁺与Pb²⁺胁迫对黑麦草初期生长的影响,结果表明：4种重金属对种子发芽率抑制效应相对较小,尤其Cu²⁺与Zn²⁺的抑制作用最小。高浓度Cu²⁺、Cd²⁺胁迫对株高、根系长度、地上生物量的抑制作用相对较大,尤其Cu²⁺对根系生长的抑制效应最大,在300 mg·L^-1下,与对照相比,根长最高下降了 85.48%。高浓度Cd²⁺胁迫显著降低了叶绿素含量,在300 mg·L^-1时比对照降低了45.51%;与对照相比,Cu²⁺与Zn²⁺所有处理都增加了叶绿素含量。从递进胁迫进程看,一些重金属对某一生长指标的影响往往表现在低浓度具有促进作用,而高浓度又存在明显的抑制效应。     

污染对拟寡水螅形态损伤的扫描电镜观察

运用扫描电镜技术对不同浓度梯度的Pb²⁺和Cd²⁺重金属离子处理下的拟寡水螅（Hydra pseudoligactis）形态学变化进行了观察。结果表明：水螅形态变化主要表现为与Pb²⁺和Cd²⁺浓度、水螅世代数目以及离子种类的相关性。与空白对照相比,处理组在Cd²⁺≥0.04 mg·L^-1,Pb²⁺≥0.25 mg·L^-1浓度下时,随着培养世代数目的增加,水螅体表逐渐发生一些不可逆的变化,皮层腐蚀,结构裂解;体壁胚层结构模糊,组织松散,刺丝囊肿胀裸露甚至破裂;上皮肌肉细胞、间细胞、刺细胞等数目减少并变形。同时,Cd²⁺处理组对其形态学的损伤和致畸作用均明显强于相对应世代数的Pb²⁺处理组。     

汞、镉、铜污染对鱼草细胞膜系统的毒害作用

通过生理生化反应测定、激光共聚焦扫描显微镜及透射电镜观察等实验手段,研究了汞（Hg²⁺）、镉（Cd²⁺）、铜（Cu2⁺）对高等水生植物鱼草(Cabomba caroliniana A. Gray)细胞膜系统的毒害作用.结果表明：在3种重金属离子作用下,鱼草叶细胞活性氧（ROS）与丙二醛（MDA）含量上升,保护酶系统活性紊乱,膜脂过氧化程度加剧;质膜受损,膜透性增加,质壁分离;叶绿体膨胀至解体,类囊体膜上的光合色素光激发过程受阻,平均自发荧光强度降低;线粒体嵴突膨胀、减少,膜破损;核膜破裂.Hg²⁺、Cd²⁺、Cu²⁺对鱼草细胞膜系统的影响存在着一定的剂量效应关系.膜系统的稳定性在植物抗重金属胁迫的过程中起着关键性的作用.鱼草对Hg²⁺污染较为敏感,致死浓度为0.3～0.5 mg·L^-1,而对Cd²⁺、Cu²⁺具有较强的抗性,可用作生物防治中的抗性植物.     

香根草对重金属铅离子的胁迫反应研究

研究了Pb²⁺对香根草生理生态指标的影响.结果表明, 随水培液中Pb²⁺浓度的增加(0～8 mmol·L^-1),香根草苗的生长受到严重影响;叶片电导率增大;SOD活性先上升后下降,但均高于对照,其活性与Pb ²⁺浓度呈正相关;POD和CAT活性虽也是先上升后下降,但在高浓度(＞4 mmol·L^-1)的Pb²⁺处理下,酶活性均低于对照,其酶活性与Pb²⁺浓度呈显著负相关.可以认为,酶活性升高是由于香根草苗对Pb2+胁迫做出的应激反应,而高浓度Pb²⁺却对香根草苗的保护酶活性有抑制作用.     

青霉菌Penicillium janthinellum菌株GXCR的高抗重金属盐及其对Cu2+和Zn2+离子吸收的特性

从广西某矿区污泥中分离了一株高抗Cu²⁺的真菌,编号为GXCR,根据形态和5.8SrRNA基因的内转录间隔子区的DNA序列同源性将其鉴定为Penicilliumjanthinellum。GXCR能够耐200mmolL^-1的Cu²⁺,在5mmolL^-1Mn²⁺存在下,可在含800mmolL^-1Cu²⁺的PDA上生长。在PDA培养基上,限制GXCR生长的其它金属盐的最小浓度(mmolL^-1)依次为:Zn²⁺,>1200;Al³⁺,>500;Na⁺,>250;Mn²⁺,>200;Cd²⁺,50;Cr³⁺,>60;Cr⁶⁺,>3;Ni²⁺,20;Pb²⁺,50。对Cu²⁺、Cr⁶⁺、Pb²⁺和Zn²⁺,的抗性是pH依赖性的,在pH37,随着pH的升高,其抗性急剧下降。在含3种金属盐混合物的PDL(未添加琼脂的PDA)中的GXCR生长的正交实验结果表明:金属盐之间存在显著的毒性协同效应;毒性协同效应强度不仅与盐的种类也与组成盐之间的浓度相关;GXCR有较高的抗3种金属盐混合物的能力。原子吸收测定结果表明:在含20mmolL^-1Cu²⁺去离子水溶液中,未经NaOH预处理的自然菌体的Cu2+吸收量为38.1mgg^-1干菌体     

Cd2+和Pb2+对花翅摇蚊(Chironomus kiiensis)幼虫生长发育的影响及富集效应

河流、湖泊等水生环境中普遍存在的重金属污染破坏水生生态系统并间接威胁人类健康。为探究重金属胁迫下水生昆虫花翅摇蚊（Chironomus kiiensis）生态毒理,测定了重金属Cd²⁺和Pb²⁺胁迫对花翅摇蚊化蛹率和羽化率的影响,检测了摇蚊的口器致畸与富集效应。研究结果表明,Cd²⁺和Pb²⁺影响摇蚊幼虫化蛹和羽化过程,单一重金属离子处理14 d Pb²⁺处理组的化蛹率和羽化率分别为22.22%和8.89%,低于Cd²⁺的化蛹率（25.56%）和羽化率（11.11%）,表现出更强的抑制效应。混合离子1：2和2：1配比处理组化蛹率和羽化率均为11.11%和4.44%,显著低于单一重金属离子胁迫下的化蛹率和羽化率。单一重金属离子及混合离子处理均能导致花翅摇蚊幼虫口器致畸,表现为上颚前齿断裂,中齿和基齿磨损、缺失,下唇板齿部不规则,下唇板边缘齿与中央齿磨损、断裂、增生、缺失。不同重金属离子处理下幼虫口器致畸率不同,并与暴露时间呈正相关,其中1：2配比处理14 d致畸率达到40.61%。重金属离子在摇蚊幼虫体内产生生物富集效应,单一重金属离子处理下的Pb²⁺富集含量7 d至14 d由11.46 mg/kg上升至31.32 mg/kg,不同配比混合离子处理下Pb²⁺富集含量均呈增加趋势,其中1：2配比处理组由15.48 mg/kg上升至42.50 mg/kg,而Cd²⁺在单一重金属与1：1混合离子处理组7 d至14 d的富集含量无显著性变化,2：1配比处理组由14.20 mg/kg下降至9.52 mg/kg,1：2配比由5.85 mg/kg上升至20.99 mg/kg。这些研究结果表明Cd²⁺和Pb²⁺胁迫影响花翅摇蚊幼虫生长发育且口器出现畸型,与重金属在幼虫体内的富集密切相关,为研究重金属对水生生态系统多重效应提供了理论依据。     

基因工程菌大肠杆菌JM109富集废水中镍离子的研究

利用通过基因工程技术所构建的在细胞内同时表达出高特异性镍转运蛋白和金属硫蛋白的基因工程菌富集水体中的镍离子。菌体细胞对Ni²⁺的富集速率很快,富集过程满足Langmuir等温线模型。与原始宿主菌相比,经基因改造的基因工程菌不仅最大镍富集容量增加了5倍多,而且对pH值、离子强度的变化及其它共存重金属离子的影响都呈现出更强的适应性。相比而言,Na⁺、Ca²⁺、Cd²⁺、Pb²⁺的影响较小,但Mg²⁺、Hg²⁺和Cu²⁺所引起的负面效应较大。进一步的实验表明基因工程菌对Ni2+的富集行为不需要外加营养物质。     

Cu胁迫对狭叶香蒲体内元素吸收分配的影响

采用水培法,研究了不同浓度Cu²⁺胁迫下狭叶香蒲（Typha angustifolia）体内Cu及其他元素吸收分配的变化。结果表明：狭叶香蒲地上部和根系累积的Cu量均随Cu²⁺浓度升高显著增加;在同一浓度Cu²⁺胁迫下,根中Cu的累积量明显高于地上部。根系同一组织中的Cu百分含量随Cu²⁺浓度的升高均显著增加;同一Cu²⁺浓度下,根系各组织中Cu含量均表现为：中柱>皮层>表皮。低浓度（1和5 mg·L^-1）Cu²⁺对地上部及根中Ca、Mg含量及地上部Mn含量均无显著影响,但高浓度（80和100 mg·L^-1）Cu²⁺可促进植株对Ca的吸收,显著降低对Mg﹑Mn和Zn的吸收。较高浓度（55～100 mg·L^-1）Cu²⁺胁迫后,根系各组织对Ca的吸收增加,对Zn的吸收降低;55～80 mg·L^-1 Cu²⁺胁迫下根系不同组织对Cl和K的吸收增加,但高浓度（100 mg·L^-1）Cu²⁺胁迫下则显著降低。根系累积的Ca、Zn和K主要分配到中柱中,Cl主要分配到皮层中.     

AtsHsp17.6-CⅠ和AtsHsp17.6-CⅡ基因对非生物胁迫的应答研究

小分子热激蛋白是植物受到热胁迫后的主要表达产物之一,与植物细胞耐热有密切关系。该研究发现,拟南芥小分子热激蛋白基因AtsHsp17.6-CⅠ和AtsHsp17.6-CⅡ 除热激之外,重金属离子Ni⁺、Pb²⁺、Cu²⁺、Zn²⁺和Al³⁺均能诱导这2个热激蛋白基因的表达;氧化胁迫和渗透胁迫同样也能诱导它们表达。该研究将由CaMV35S启动子驱动的这2个小分子热激蛋白基因导入拟南芥,RT-PCR分析表明,2个小分子热激蛋白基因在转基因植物中呈现组成型表达。实验结果表明,组成型表达小分子热激蛋白基因AtsHsp17.6-CⅠ的转基因植物表现出对6 μmol·L^-1 Cd²⁺胁迫、0.4% NaCl胁迫的耐受性。研究表明,这2个小分子热激蛋白基因可能参与着多种抗逆途径,推测其能够减轻或抵抗逆境胁迫引起的伤害并对其进行修复。     

Compartments for the Management of Municipal Solid Waste

Despite technological developments and improved liner-material applications, heavy metals in landfill leachate still penetrate the soil profile, polluting the soil and ground-water. An alternative approach therefore must be explored to reduce heavy-metal migration in soil-bentonite landfill liners. By considering the interaction of different heavy metals and their synergetic and antagonistics behaviors, such an approach could be developed. Low mobility metals such as Cu²⁺, and Pb²⁺ inhibit the adsorption of Cd²⁺ which is a moderate-mobility metal and Cu²⁺ sorption is decreased by the presence of Zn²⁺ and Cd²⁺. Therefore, Zn²⁺, a low-mobility metal, cannot be grouped with Cu²⁺. This way, four compatible metal groups have been identified: (1) low mobility: Pb²⁺, Cu²⁺, and Ag, (2) low mobility: Zn²⁺ and Cr³⁺; (3) moderate mobility: As²⁺, Fe²⁺, and Ni²⁺; (4) high mobility: Cd²⁺ and Hg²⁺. Cd²⁺ with a moderate mobility pattern is synergetic to Fe²⁺ and is more mobile with Ni²⁺. Therefore, Cd²⁺ is separated from the moderate-mobility group and is consigned with Hg, a high-mobility metal. The liner materials suitable for Hg²⁺ are assumed to be suitable for Cd²⁺ as well. Based on this concept, and to reduce heavy metal mobility, wastes should be segregated on compatibility basis according to their heavy metal contents before being disposed in different individual compartments. For wastes containing several incompatible heavy metals, sorting should be based on the heavy-metal with the highest concentration. Another solution is the manufacturing of products using compatible heavy metal combinations and then labeling them accordingly. Such waste segregation and landfill compartmentalization lowers risks of groundwater contamination and liner cost.     

Enhanced heavy metal immobilization by a bacterial-chitosan complex in soil

Soil contaminated with heavy metals (e.g., Pb²⁺, Cu²⁺, and Zn²⁺) was treated with aminopoly-saccharide chitosan alone or a strain of the bacterium Bacillus subtilis to determine their effects on metal ion accumulations. Phosphatase and Chitosanase production were also assayed. The combined bacterial-chitosan treatment showed the greater accumulation of Zn²⁺ followed by Cu²⁺ as compared to single treatments, while Pb²⁺ did not show a marked accumulation by either single or combined treatments.     

Multi-metal biosorption and bioaccumulation by Exiguobacterium sp. ZM-2

The present work deals with the biosorption performance of dried and non-growing biomasses of Exiguobacterium sp. ZM-2, isolated from soil contaminated with tannery effluents, for the removal of Cd²⁺, Ni²⁺, Cu²⁺, and Zn²⁺ from aqueous solution. The metal concentrations studied were 25 mg/l, 50 mg/l, 100 mg/l, 150 mg/l and 200 mg/l. The effect of solution pH and contact time was also studied. The biosorption capacity was significantly altered by pH of the solution. The removal of metal ions was conspicuously rapid; most of the total sorption occurred within 30 min. The sorption data have been analyzed and fitted to the Langmuir and Freundlich isotherm models. The highest Q_max value was found for the biosorption of Cd²⁺ at 43.5 mg/g in the presence of the non-growing biomass. Recovery of metals (Cd²⁺, Zn²⁺, Cu²⁺ and Ni²⁺) was found to be better when dried biomass was used in comparison to non-growing biomass. Metal removal through bioaccumulation was determined by growing the bacterial strain in nutrient broth amended with different concentrations of metal ions. This multi-metal resistant isolate could be employed for the removal of heavy metals from spent industrial effluents before discharging them into the environment.     

径流雨水中溶解性有机质特征演化及其对典型污染物迁移和生物有效性的影响

地表径流污染已经逐渐成为城市面源污染的重要组成部分。其中溶解性有机质DOM (Dissolved organic matter)是有机污染物的主要组成部分。DOM中因为含有大量不饱和结构、官能团,其中包括羟基、羧基、羰基、胺基等,这些结构容易与径流中重金属结合发生络合反应,改变重金属的赋存形态,从而对其迁移转化及其生物有效性产生很大的影响。本文以北京市地表径流为研究对象,研究城市地表径流在冬、夏季不同功能区不同下垫面中溶解性有机质特征及其与典型重金属的作用机制,通过荧光淬灭滴定实验,研究夏季径流雨水中DOM的不同组分与重金属Cu~(2+)、Pb~(2+)、Zn~(2+)之间的结合机制。研究结果显示PARAFAC将获得的样品都分解成2类6个不同的组分,1种腐殖酸,1种类蛋白;类蛋白物质的荧光强度与Cu~(2+)、Pb~(2+)的淬灭率要强于腐殖酸,而Zn~(2+)则呈现相反趋势;通过使用二维相关同步光谱发现DOM对重金属Cu~(2+)、Pb~(2+)、Zn~(2+)的敏感性呈现递减趋势,二维相关异步光谱发现Cu~(2+)、Pb~(2+)会先与位于270—300nm附近类蛋白光谱带反应,Zn~(2+)则会先与330nm附近的腐殖酸光谱带反应。     

Changes in lipid composition in the tissues of fresh-water plant <Emphasis Type="Italic">Hydrilla verticillata</Emphasis> induced by accumulation and elimination of heavy metals

Qualitative and quantitative composition of lipids was investigated in fresh-water vascular plant Hydrilla verticillata (L. fil.) Royle in the course of the accumulation and elimination of heavy metals (HM). The plants were incubated in 100μM solutions of metal nitrates for 10 days. The accumulation of Cu²⁺, Zn²⁺, and Pb²⁺ and their elimination from the plants depended on the duration of exposure and chemical nature of the metal. Accumulation of lead and copper salts was the greatest on the 3rd day, and zinc, on the 10th day. It was associated with changes in the composition of total lipids, polar lipids, and fatty acid (FA). Copper ions suppressed lipid metabolism stronger than other metals. Zn²⁺ and Pb²⁺ induced the accumulation of biomass and elevated the content of some phospholipids and glycolipids. The detected changes (decrease or increase) were observed both during the incubation with HM and within an afterstress period when the plants recovered in the medium free of metals. Judging by their effect on the content of lipids and FA, HM form a series: Cu²⁺ > Zn²⁺ > Pb²⁺. The responses of plant lipid metabolism to the metals of various chemical nature are discussed.     

Enhanced heavy metal immobilization by a bacterial-chitosan complex in soil

Soil contaminated with heavy metals (e.g., Pb²⁺, Cu²⁺, and Zn²⁺) was treated with aminopoly-saccharide chitosan alone or a strain of the bacterium Bacillus subtilis to determine their effects on metal ion accumulations. Phosphatase and Chitosanase production were also assayed. The combined bacterial-chitosan treatment showed the greater accumulation of Zn²⁺ followed by Cu²⁺ as compared to single treatments, while Pb²⁺ did not show a marked accumulation by either single or combined treatments.     

Effects of heavy metals on the Ca2+-ATPase activity present in gill cell plasma-membrane of mussels (Mytilus galloprovincialis Lam.)

1. Heavy metals (Hg²⁺, Cu²⁺, Cd²⁺, Zn²⁺, Pb²⁺) at micromolar concentrations strongly inhibit the Ca²⁺-ATPase activity present in the plasma-membrane obtained from the gill cells of Mytilus galloprovincialis Lam. Heavy metals act through inhibition of the formation of the phosphorylated intermediate.2. All the heavy metals tested inhibit the Ca²⁺-ATPase activity, the effect following the order: Hg²⁺ > Pb²⁺ > Cu²⁺ > Cd²⁺ > Zn²⁺; the simultaneous addition of different heavy metals causes a summatory inhibition of the enzyme activity; addition to the reaction mixture of GSH at a final concentration of 0.5 mM, reverses inhibitory effects of heavy metals.3. The inhibitory effects of Cu²⁺ on Ca²⁺-ATPase are highly enhanced by addition of ascorbate to the reaction mixture. In the presence of ascorbate (100 μM), copper strongly stimulates the lipid peroxidation damage of the gill plasma-membranes, a result that may explain the high copper cytotoxicity.     

Effect of heavy metal ions on growth and biochemical characteristics of photosynthesis of barley and maize seedlings

The effects of Cu²⁺, Zn²⁺, Cd²⁺ and Pb²⁺ on growth and the biochemical characteristics of photosynthesis were more expressed in barley (Hordeum vulgare L.) than in maize (Zea mays L.) seedlings. The barley and maize seedlings exhibited retardation in shoot and root growth after exposure of Cu²⁺, Cd²⁺ and Pb²⁺. The Zn²⁺ions practically did not influence these characteristics. The total protein content of barley and maize roots declined with an increase in heavy metal ion concentrations. The protein content of barley shoots was only slighly decreased with an increase in heavy metal ion concentrations, but the protein content in maize shoots was increased under the same conditions. The chlorophyll content was decreased in barley shoots and increased in maize. The ribulose-l,5-bisphosphate carboxylase (RuBPC, EC 4.1.1.39) and phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) activities were decreased drastically by Cu²⁺, Cd²⁺ and Pb²⁺ in thein vivo experiments. The tested heavy metal ions affect photosynthesis probably mainly by inhibition of these key carboxylating enzymes: this mechanism was studied in thein vitro experiments.