珠江口海岸带沉积物中酸可挥发性硫化物与重金属生物毒效性研究

对珠江口淇澳岛附近2个站(QA-2、QA-5)柱状沉积物中酸可挥发性硫化物(AVS)和同步提取重金属(SEM)的垂直分布规律进行了研究。研究表明,AVS在2个站沉积物中的质量摩尔浓度分别为3.44～13.13μmol/g和11.67～15.39μmol/g。QA-2站沉积物中AVS的质量摩尔浓度随深度增加,QA-5站AVS的质量摩尔浓度垂直剖面上没有明显的变化趋势,反映了不同沉积环境对AVS质量摩尔浓度分布特征的影响。2个站的SEM的质量摩尔浓度在沉积物垂直剖面上都随深度增加逐渐减小,这是因为珠江三角洲工业和城市的发展、污染物排放增加导致了重金属在沉积物中的累积。QA-2站表层沉积物(0～5 cm)SEM/AVS>1,表明可能存在重金属的生物毒效应;同时,SEM中Cu和Cd的质量摩尔浓度超过了它们的重金属浓度阈值(TEL),有可能产生重金属毒性作用;QA-2站5 cm以下和QA-5站沉积柱中SEM/AVS<1,不存在重金属的生物毒效性。

毒死蜱的微胶囊化及其长效毒杀性能

以异佛尔酮二异氰酸酯三聚体、二甲苯、毒死蜱为油相,聚乙烯醇、水、十二烷基磺酸钠为水相,通过界面聚合法,制备出高稳定性毒死蜱微胶囊悬浮剂。通过扫描电镜照片研究了微胶囊的表面形貌和平均粒径,用紫外分光光度法研究了微胶囊对毒死蜱的初期包封率及其释放特性;壁材及微胶囊的热行为通过热重分析进行了表征;用斜纹夜蛾3龄幼虫进行了生测初步试验。结果表明,微胶囊是平均粒径为10μm左右的球形颗粒;壁材热稳定性良好,微胶囊的初期包封率均高于95%,在低于45℃的水相中毒死蜱在微胶囊中能长期稳定储存,微胶囊化的毒死蜱具有持久的生物毒杀性。

利用玉米浸泡液制备苏云金杆菌生物杀虫剂

以玉米淀粉生产过程中的浸泡液作为原料培养基,在5L发酵罐中培养苏云金杆菌生物杀虫剂,并以常规黄豆粉培养基为对照,考察了苏云金杆菌在玉米浸泡液中的生长代谢状况(包括菌体形态、菌数增长与芽孢形成)以及48h发酵液的生物毒效.研究表明,无需添加其它成分及前处理,玉米浸泡液所含营养成分即可满足苏云金杆菌生长需求,其培养的总活菌数及芽孢数在27h可达最大值1.51×109CFU.mL-1和1.41×109CFU.mL-1,分别比常规培养基高出59%和85%,芽孢形成与晶体释放提前约9～12h;36h扫描电镜(SEM)观察表明,发酵36h浸泡液中大部分芽孢囊已经自溶,游离出卵圆形芽孢与菱形的晶体;而此时常规培养基正处于芽孢形成后期,只有极少数的游离晶体与芽孢;48h发酵终点的生物毒效结果显示,以浸泡液为培养基的苏云金杆菌发酵液毒效(891.51IU.μL-1)比常规培养基高89%.本试验为浸泡液的再利用提供了一条崭新的途径,同时降低了杀虫剂的生产成本.

巢湖底泥营养盐与酸性可挥发性硫化物及同步可提取重金属的耦合效应研究

在野外调查监测的基础上,阐述了各类污染物的空间分布规律,深入挖掘了营养盐与AVS 和SEM 的相互关系,结果表明:(1)巢湖底泥中TN、TP含量空间分布规律与AVS及SEM有所不同:底泥中TN、TP含量西北湖区>东部>中部。而AVS、ΣSEM含量则东南湖区>西北和中部;(2)TN、TP可通过诱发蓝藻爆发改变湖泊环境,促使底泥中AVS与SEM减少;(3)巢湖底泥中最主要的ΣSEM贡献元素是Ni、Zn,Spearman相关性分析二者加和与ΣSEM表现出极显著相关且系数达到0.941。仅就底泥AVS及ΣSEM看来,除姥山岛附近可能存在潜在生物毒效性外,其余部分重金属暂不会对底栖生物产生急性或慢性毒性,湖中营养盐的增加会间接放大底泥中重金属对底栖生物的危害。

Effect of Potato Extract on its Phenolic Metabolism,SAGs Accumulation and Allelopathic Autotoxicity

[Objective] The paper was to study the effect of potato extract on its phenolic metabolism,SAGs accumulation and allelopathic autotoxicity.[Method] With water treatment as control,the effects of aqueous extracts of potato bud,leaf-stem and tuber on its morphological characteristics,phenolic metabolism,glycoside alkaloids accumulation and allelopathic autotoxicity were studied.[Result] After the treatment of aqueous extract,the germination rate of potato reduced,germination was delayed,the plants became smaller,and the growth of root slowed down;the content of phenolic substances in roots,stems and leaves of potato increased,glycoside alkaloids accumulated,the activity of PPO and PAL increased.The effects of aqueous extract treatment on germination,growth,phenolic metabolism,glycoside alkaloid content and allelopathic autotoxicity successively were bud extractleaf-stem extracttuber extractcontrol.Treatment of aqueous extract did not affect the distribution of phenolic substances and glycosidic alkaloid in potato.[Conclusion] Phenolic substances and glycosidic alkaloid involved in the allelopathic autotoxicity of aqueous extract of potato,which had inhibition effect on germination and growth of potato.

Application of Spodoptera litura Nucleopolyhedrovirus for Crop Pest Control

The laboratory bioassay and field control efficacy of Spodoptera litura nucleopolyhedrovirus（Spli NPV） Chenzhou strain were preliminarily examined. The efficient artificial propagation method was to feed the host larvae with virus suspension,and the average mortality of the insects was 65.0%. The death peak of the pests appeared 4-8 d after virus infection. The high temperature, high humidity and poor light could help the virus infection and propagation. Filed control efficacy of Chenzhou strain was 86.6% in laboratory, which was better than of another commercial strain. The corrected control efficacy of this strain was 88.4% the field, which was higher than that of avermectin pesticide significantly. It was detected that the occlusion body（OB） concentration of the initial virus＇ s stock solution was 1.03×1011OBs/ml,and it was a strong SpliNPV strain, as it showed an excellent efficacy to control the pest Spodoptera litura, and thus there will be a good prospect of application and development of this SpliNPV strain.

Biodegradation of microcystin-RR and -LR by an indigenous bacterial strain MC-LTH11 isolated from Lake Taihu

The indigenous bacterial strain MC-LTH11 with the capability of degrading microcystin-RR MC-RR and microcystin-LR MC-LR was successfully isolated from Lake Taihu.The bacterium was identified as Stenotrophomonas sp. which possessed a mlrA gene. The MC-LTH11 thoroughly degraded MC-RR and MC-LR with the initial concentration of 37.13 mg/L and 18.49 mg /L respectively in the medium containing crude microcystins extract within 6 d.The degradation rates were affected by temperature pH initial MCs concentration and the kinds of media. Additionally the bacterial strain MC-LTH11 also degraded thoroughly microcystins in the water body of Lake Taihu within 1 d.These results suggest that the Stenotrophomonas sp.MC-LTH11 has the capacity to bioremediate water bodies contaminated by microcystins and may contribute to the degradation of microcystins after the outbreak of harmful cyanobacterial blooms in Lake Taihu.

Advances in environmental behaviors and effects of dissolved organic matter in aquatic ecosystems

Dissolved organic matter(DOM) is a group of compounds that have complex chemical structures and multiple interactions with their surrounding materials. More than one trillion tons of DOM are stocked in the world's aquatic ecosystems. DOM is a very important part of aquatic ecosystem productivity and plays a crucial role in global carbon cycling. DOM has rich environmental behaviors and effects such as influencing the bioavailability of contaminants, serving as an important inducer of reactive oxygen species(ROS), and protecting aquatic organisms from the harm of dangerous ultraviolet radiation. There have been many systematic studies on the composition, structure, and sources of DOM because such studies are much easier to conduct than studies on the environmental behaviors and effects of DOM. Due to many factors, the research systems of DOM's environmental behaviors and effects are still being developed and have become a hotspot of environmental science. This review paper focuses on some critical progress, problems, and trends of DOM's environmental behaviors and effects in aquatic ecosystems, including mutual exchange mechanisms between DOM and particulate organic matter(POM) with influencing factors, photochemical behaviors of DOM especially inducing ROS, binding interactions between DOM and anthropogenic organic contaminants(AOC), interactions between DOM and microorganisms, effects of DOM on pollutants' bioavailability, ecotoxicity, and ecological risks. Hopefully, this paper will contribute to a more systematic understanding of the DOM environmental behaviors and effects and to promoting further relevant studies.

Toxic effects of metal oxide nanoparticles and their underlying mechanisms

Nanomaterials have attracted considerable interest owing to their unique physicochemical properties.The wide application of nanomaterials has raised many concerns about their potential risks to human health and the environment.Metal oxide nanopartides（MONPs）,one of the main members of nanomaterials,have been applied in various fields,such as food,medicine,cosmetics,and sensors.This review highlights the bio-toxic effects of widely applied MONPs and their underlying mechanisms.Two main underlying toxicity mechanisms,reactive oxygen species（ROS）-and non-ROS-mediated toxidties,of MONPs have been widely accepted.ROS activates oxidative stress,which leads to lipid peroxidation and cell membrane damage.In addition,ROS can trigger the apoptotic pathway by activating caspase-9 and-3.Non-ROS-mediated toxicity mechanism includes the effect of released ions,excessive accumulation of NPs on the cell surface,and combination of NPs with specific death receptors.Furthermore,the combined toxicity evaluation of some MONPs is also discussed.Toxicity may dramatically change when nanomaterials are used in a combined system because the characteristics of NPs that play a key role in their toxicity such as size,surface properties,and chemical nature in the complex system are different from the pristine NPs.

Impacts of climate change on the ecotoxicology of chemical contaminants in estuarine organisms

Global climate change effects will vary geographically, and effects on estuaries should be independently considered. This review of the impacts of climate change on the ecotoxicology of chemical contaminants aims to summarize responses that are specific to estuafine species. Estuarine organisms are uniquely adapted to large fluctuations in temperature, salinity, oxygen, and pH, and yet future changes in climate may make them more susceptible to chemical contaminants. Recent research has hig- hlighted the interactive effects of chemical and nonchemical stressors on chemical uptake, metabolism, and organism survival. Assessments have revealed that the nature of the interaction between climate variables and chemical pollution will depend on es- tuarine species and life stage, duration and timing of exposure, prior stressor exposure, and contaminant class. A need for further research to elucidate mechanisms of toxicity under different abiotic conditions and to incorporate climate change factors into toxicity testing was identified. These efforts will improve environmental risk assessment of chemical contaminants and manage- ment capabilities under changing climate conditions [Current Zoology 61 （4）： 641-652, 2015].