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1.
土壤中金属的生物可给性及其动态变化的研究   总被引:2,自引:0,他引:2  
土壤中金属的生物可给性常应用于人体健康风险评价,如能准确地判定土壤中金属在胃肠阶段不同时间的溶出动态,研究者就可以更好地分析其对人体的健康风险。本文采集5种不同地区的重金属污染的土壤,利用改进的PBET方法,分别在胃阶段的20、40、60、80 min以及小肠阶段的1、2、3、4、5 h时取样并分析,探究土壤中8种金属元素(As、Al、Cd、Cr、Fe、Mn、Ni、Pb)的生物可给性和溶出动态,探讨造成金属溶出动态变化的影响因素,对其溶出机理进行初步探究。研究结果表明,Fe、Al的生物可给性较低,并且在胃肠阶段差异较小。与胃阶段相比,土壤中Pb、Cd的生物可给性在小肠阶段明显降低,而As、Mn、Cr、Ni的生物可给性在小肠阶段均升高。升幅最大的两个元素是Ni、Cr,其小肠阶段的平均生物可给性分别升高61.4%、29.9%。在溶出量随时间变化方面,在胃阶段,假定1 h时溶出率为100%。20 min时,土壤中Fe、Ni的平均溶出率较低,分别为59.3%、56.8%,其他6种金属元素的平均溶出率在71.2%~79.5%。As、Cd、Pb的溶出速率是先快后慢,Cr和Ni的溶出速率是先慢后快,而Fe、Mn、Al的溶出速率基本保持不变。在小肠阶段,假定4 h时溶出率为100%。Al、As、Cd、Mn的溶出率基本不变。1 h时,土壤中Cr(土壤A除外)、Ni的平均溶出率最低,分别为31.5%、32.7%,而5 h时,Fe、Cr、Ni的溶出率还在升高。由此可见,土壤中不同金属元素的生物可给性以及溶出动态是有明显差异的。  相似文献   

2.
包装材料及食品中纳米材料的检测与表征技术   总被引:1,自引:0,他引:1  
随着纳米技术的发展,纳米材料在包装行业及食品工业中得到了广泛的应用。然而,纳米材料的安全应用高度依赖于对其生物及环境效应的了解。有研究表明,纳米材料对人类健康及生态环境存在着潜在危害,这使得纳米材料的安全性成为毒理学领域的热点研究课题。同时纳米材料的安全性问题也成为纳米复合包装材料及纳米食品研究和开发的新瓶颈。在对纳米材料没有充分认识的情况下,为了消费者和生态环境的安全,必须控制包装材料及食品中纳米颗粒的种类、来源、含量及可能的释放,这就需要可靠的方法对纳米颗粒的性质和结构进行检测及表征。首先,综述了目前纳米材料在复合包装材料及食品加工中的应用,然后总结了包装材料及食品中纳米材料的检测技术及表征方法,例如显微技术、色谱分离技术、光谱与质谱技术等。由于纳米材料的理化性质参数众多,应用多种分析手段来检测和表征纳米材料成为必然。最后对目前检测技术及表征方法的不足和今后发展方向进行了探讨。  相似文献   

3.
汞是一种高毒性且具有持久性的重金属污染物,汞污染的治理与修复在近几十年一直是国内外研究热点.了解微生物对汞赋存形态的转化作用,对汞污染的治理与修复具有重要意义.总结汞的不同赋存形态、毒性及对应的常用分析方法,其中甲基汞(methyl mercury,MeHg)是毒性最强的汞形态之一.环境中汞的化学形态能发生转化,尤其以微生物驱动的汞的甲基化、MeHg的去甲基化和汞的氧化还原最为常见.依据汞转化类型将汞转化相关微生物分为汞甲基化、MeHg去甲基化、汞还原、汞氧化等类群,将对应的汞转化作用机制分为基于hgcAB基因的汞甲基化、基于mer操纵子基因的MeHg去甲基化和Hg2+还原、胞内过氧化氢酶介导的Hg0氧化.微生物汞转化过程不仅受到pH和温度的显著影响,而且还受到汞的赋存形态和游离汞的浓度、微生物种/群结构与功能、矿物种类、中间体和次生产物及其交互作用的影响,基于此,提出正确客观表征汞的微生物转化过程需要综合分析微生物组和矿物组的变化规律及其交互作用的综合效应.针对酸性矿山废水(AMD)极端环境微生物汞转化研究的不足,未来的工作将聚焦结合多组学手段、同步辐射谱学和密度泛函理论(DFT)计算等分析技术研究汞赋存形态的微生物转化过程,分析和阐明汞转化中间体的键合作用方式和转化机制,从而为AMD汞污染的预防、治理和修复提供依据.(图2表2参107)  相似文献   

4.
First results are presented from the Urban geochemistry of Tallinn, a project supported by the Scientific and Environmental Affairs Division of NATO. The distribution of chemical elements in 532 samples of the topsoils from the territory of the biggest industrial centre of Estonia (pop. 500,000) is interpreted. Statistical analysis and mapping of major and trace elements at the territory of the Tallinn region and of the city were performed and background values and local anomalies of chemical elements on the territory were determined. The investigation focussed on the determination of zones with anomalously high concentrations of elements and the relationships of soil contamination with different pollution sources. The increase of the element concentrations has natural as well as anthropogenic origins. A detailed comparative analysis of the element distributions and the results of a factor analysis showed that the distribution of the major chemical elements depended mainly on the composition of the underlying sedimentary rocks.The territory of Tallinn is characterised by relatively high and widespread concentrations of Ba, Cr, Ga, Ni, Ti and Zn. Especially intensive local concentrations were determined for As, Cr, Mn, Ni, Pb, S, V and Zn, which are typical for the local pollution of the soils by industrial sources. The levels of As, Cr, Mn and V are more than three times. Pb and Zn are more than five times higher in the geochemical anomalies than for background levels. For the Tallinn region two major associations of elements connected with industrial pollutions of the soil are typical: the first association includes Ba, Cr, Mn, Ni and partly Fe and the second one includes As, Pb and Zn. For the city of Tallinn an increase of Ag, Ba, Be, La, Pb, Sn and Zn concentration in the soil was detected. Ba, Cr, Mn and Ni occur in high concentrations in the soils around Maardu. Different types of contamination sources can be identified in Tallinn and its suburbs.  相似文献   

5.
This paper studied the relationship between heavy metal concentrations of herbaceous plants and soils at four Pb-Zn mining sites in Yunnan, China. 50 herbaceous plant samples of 9 plant species from 4 families and 50 soil samples were collected and then ana1yzed for the tota1 concentrations of Pb, Cd, and Zn. The results showed that the average concentrations of Pb, Cd, and Zn in soil samples were 3772.83, 168.81, and 5385.65 mg/kg, respectively. The average concentrations of Pb, Cd, and Zn were 395.68, 28.14, and 1664.20 mg/kg in the shoots, and 924.12, 57.25, and 1778.75 mg/kg in the roots, respectively. Heterospecific plants at the same site and conspecific plants at various sites had different average levels of Pb, Cd, and Zn, both in the shoots and the roots. Enrichment coefficients of Pb, Cd, and Zn were greater than 1 in 2, 3, and 9 herbaceous plant samples, respectively. Translocation factors of Pb, Cd, and Zn were greater than 1 in 10, 17, and 25 herbaceous plant samples, respectively. In all 50 samples, the concentrations of Pb, Cd, and Zn between the shoots and the roots, the shoots, and the soils, and the roots and the soils had significant positive relationships.  相似文献   

6.
植物区系学中的特有现象是其研究的重点内容,对特有现象的概念、类型、起源及其研究意义作了详细的论述;其次,总结了中国植物区系的基本情况、生活型、分布区学、水平分布、垂直分布与起源等研究成果;第三,介绍了研究特有现象的形态-地理学方法、细胞地理学方法和等位酶分析方法;第四,指出了中国植物区系中特有现象研究所面临的困境,认为应该集中力量重点研究滇黔桂、横断山脉以及华中等3个地区的植物区系基本特征、组成、起源、演化与扩散等内容.  相似文献   

7.
It was proved by in vitro and animal experiments, that the toxicokinetics (resorption, distribution, deposition and excretion) and, in connection with this, also the toxicity of the metals Cadmium (Cd), Copper (Cu) and Zinc (Zn) is closely associated to the low molecular weight protein Metallothionein (Mt). There is a considerable lack of information on the Mt concentration in human tissues and its correlation to Cd, Cu and Zn. Therefore the concentrations of Cd, Cu, Zn and Mt were determined quantitatively in liver and kidney samples of 184 deceased. The dependence of these concentrations from each other and from further parameters, i.e. age, sex, drinking and smoking habits, or diseases of the organs, is studied. Scalar values (concentrations, age) were compared by Spearman rank correlations. The influence of non‐scalar factors (i.e. sex, diseases etc.) was proved by comparison of the geometric means of the Cd, Cu, Zn and Mt concentrations in the tissues of the corresponding subgroups. The manner of influence of the main factors will be discussed.  相似文献   

8.
水深和氮素是影响湿地植物生长的关键因素,研究两者对功能性状的影响有助于预测未来环境变化下湿地植物的生长与分布趋势.以三江平原沼泽湿地3种优势植物(漂筏苔草Carex pseudocuraica、毛苔草Carex lasiocarpa和燕子花lris laevigata)为研究对象,设置3个水深(0、5、15 cm)和3...  相似文献   

9.
金昌市郊农田土壤Cu,Zn,Ni形态分布特征与生物有效性评价   总被引:3,自引:1,他引:2  
通过野外调查和室内测试分析,研究了金昌市郊农田土壤重金属Cu,Zn和Ni的形态特征,并以麦粒中重金属含量为重点进行了Cu,Zn和Ni的生物有效性评价.结果表明,研究区域土壤重金属Cu和Ni污染严重;Cu的主要存在形态为有机结合态,Zn的主要存在形态为残渣态,而Ni的主要存在形态为潜在可利用态;三种元素的生物有效性大小顺序为NiZnCu.对麦粒中重金属健康风险进行评价反映出麦粒中Ni含量对人体健康风险较大,而Cu和Zn对人体健康风险较小.逐步回归分析结果表明,农田土壤中Cu可交换态和碳酸盐结合态对麦粒中Cu含量贡献最大,而对麦粒吸收Zn和Ni贡献最大的形态分别为Zn的碳酸盐结合态和Ni的可交换态、碳酸盐结合态、铁锰氧化态和有机结合态.土壤重金属Cu,Zn和Ni各形态分配系数较总量和各形态含量更适合表征本研究区域土壤重金属的生物有效性.  相似文献   

10.
SUMMARY

Energy transition is the process whereby there is an increase in the volume and proportion of commercial energy, to the extent that it replaces traditional fuels as the main source of energy and having enormous implications for the physical and biotic environment. This energy-environment process has rarely been the focus of research investigation in Africa. Using cross-national data drawn from the African continent, this paper examines and accounts for intercountry variations in the nature and extent of the energy transition process. The empirical analysis reveals that, for the continent as a whole, the extent to which commercial energy replaces traditional fuels is quite low. It varies between 33% and 39%. However, inter-country variations were found to be as high as 90% in countries such as Algeria, Egypt, Libya, Mauritania, Morocco and South Africa; and less than 15% for such countries as Benin, Burkina Faso, The Central African Republic, Ethiopia, Lesotho and Uganda. The key factors explaining intercounty variations in the energy transition process are the level of urbanization and the extent of forest and woodland resources. Other factors of secondary importance include economic growth, incidence of poverty, affordability of electrical appliances, energy trade status of the country in question and the price of commercial fuel. Finally, the paper shows that the identification of these key energy transition-inducing variables is a necessary prerequisite to an effective energy and environmentally sustainable development policy formulation in Africa.  相似文献   

11.
采用土培的方式,研究了不同浓度的NaCl(0,50,100,150,250,350mmol·L-1)对岑溪酸橘Citrus reticulata Blanco、龙州土柠檬CitruslimoniaOsbeck和临桂砧板柚Citrus grandis Osbeck叶片抗氧化酶(SOD、POD、CAT、APX)活性以及谷胱甘肽(GSH)、丙二醛(MDA)、超氧自由基(02]含量的影响。结果表明,随着NaCI处理浓度的增加,岑溪酸橘、龙州土柠檬和临桂砧板柚3种柑橘叶片中02均有不同程度的增加,表明在NaCI处理下3种柑橘均受到了不同程度的O2-胁迫。NaCI处理对岑溪酸橘和龙州土柠檬SOD、POD活性,临桂砧板柚MDA含量的影响不显著C〉0.0S),但引起临桂砧板柚SOD活性、岑溪酸橘和龙州土柠檬APX活性显著增加(P〈0.05)。在不同浓度的NaCI处理下,3种柑橘叶片的CAT活性均有不同程度的下降,但GSH的含量随着NaCl浓度的增加而增加,在NaCl处理浓度为350mmol·L-1时,岑溪酸橘、龙州土柠檬、临桂砧板柚GSH含量分别比对照提高了137%、59.1%、90.8%,表明GSH在解毒NaCl胁迫时起重要作用。  相似文献   

12.
Abstract: In East Africa fire and grazing by wild and domestic ungulates maintain savannas, and pastoralists historically set fires and herded livestock through the use of temporary corrals called bomas. In recent decades traditional pastoral practices have declined, and this may be affecting biodiversity. We investigated the effects of prescribed fires and bomas on savanna bird communities in East Africa during the first and second dry seasons of the year (respectively before and after the rains that mark the onset of breeding for most birds). We compared abundance, richness, and community composition on 9‐ha burned plots, recently abandoned bomas, and control plots in the undisturbed matrix habitat over a 3‐year period. Generally, recently burned areas and abandoned bomas attracted greater densities of birds and had different community assemblages than the surrounding matrix. The effects of disturbances were influenced by interactions between primary productivity, represented by the normalized difference vegetation index, and time. Bird densities were highest and a greater proportion of species was observed on burned plots in the months following the fires. Drought conditions equalized bird densities across treatments within 1 year, and individuals from a greater proportion of species were more commonly observed on abandoned bomas. Yearly fluctuations in abundance were less pronounced on bomas than on burns, which indicate that although fire may benefit birds in the short term, bomas may have a more‐lasting positive effect and provide resources during droughts. Several Palearctic migrants were attracted to burned plots regardless of rainfall, which indicates continued fire suppression may threaten their already‐declining populations. Most notably, the paucity of birds observed on the controls suggests that the current structure of the matrix developed as a result of fire suppression. Traditional pastoralism appears critical to the maintenance of avian diversity in these savannas.  相似文献   

13.
利用土壤环境资料中关于锡元素的32335个数据,癌死亡调查资料787080例,研究了胃癌、食管癌、肝癌、宫颈癌、肺癌、大肠癌、白血病、鼻咽癌、乳腺病死亡率与人鲜生活区土壤环境中锡元素的关系,结果表明。食管癌死亡率与生活区土壤中锡元素质量分数的相关性显著,肝癌、宫颈癌、鼻咽癌死亡率与生活区土壤中锻元素质量分数的相关性极显著,而胃癌、肺癌、大肠癌、白血病、乳腺癌死亡率与生活区土壤中锡元素质量分数的相共性下显著。  相似文献   

14.
Ecotourism contains the integration from ecological integrity and economic benefits to environmental and historically sensitive areas. One of the major keys of ecotourism-planning strategies is to ensure the sustainability of unique natural and cultural resources by a balance strategy between protection and use. It causes both the increase of the ecotourism awareness of local people and visitors and the decrease of the environmental problems and visitor pressures on the landscape resources of potential ecotourism areas. For this reason, the study presents the example of Iznik which is an ancient Greek, Roman, Byzantine, and Ottoman city of Nicaea with its lake, historical walls and gates, churches and early-period mosques, ceramic tiles, and agricultural activities on the southeast of Marmara Region, Turkey. It has been declared to have a different protected area status. However, the number of unsuitable management and uncontrolled economic activities has caused damage to sensitive landscape values. The aim of this research is to define ecotourism criteria for Iznik and it offers ecotourism strategies for the sustainability of sensitive landscape areas. Fieldwork, field observation, interviews and survey study with integrated multiple-criteria decision analysis and strengths-weakness-opportunities-threats (SWOT) analysis conducted with locals, tourists and experts were performed for this purpose. According to the results, among the 4 main and 15 sub-criteria of ecotourism to be in UNESCO Tentative List, the opportunity for ecotourism-planning strategy was found as the highest priority ranking. This research proposes a framework by using a priority-ranking method for the development of ecotourism strategies in the town.  相似文献   

15.
Conservation of sea snakes is virtually nonexistent in Asia, and its role in human–snake interactions in terms of catch, trade, and snakebites as an occupational hazard is mostly unexplored. We collected data on sea snake landings from the Gulf of Thailand, a hotspot for sea snake harvest by squid fishers operating out of the ports of Song Doc and Khanh Hoi, Ca Mau Province, Vietnam. The data were collected during documentation of the steps of the trading process and through interviewers with participants in the trade. Squid vessels return to ports once per lunar synodic cycle and fishers sell snakes to merchants who sort, package, and ship the snakes to various destinations in Vietnam and China for human consumption and as a source of traditional remedies. Annually, 82 t, roughly equal to 225,500 individuals, of live sea snakes are brought to ports. To our knowledge, this rate of harvest constitutes one of the largest venomous snake and marine reptile harvest activities in the world today. Lapemis curtus and Hydrophis cyanocinctus constituted about 85% of the snake biomass, and Acalyptophis peronii, Aipysurus eydouxii, Hydrophis atriceps, H. belcheri, H. lamberti, and H. ornatus made up the remainder. Our results establish a quantitative baseline for characteristics of catch, trade, and uses of sea snakes. Other key observations include the timing of the trade to the lunar cycle, a decline of sea snakes harvested over the study period (approximately 30% decline in mass over 4 years), and the treatment of sea snake bites with rhinoceros horn. Emerging markets in Southeast Asia drive the harvest of venomous sea snakes in the Gulf of Thailand and sea snake bites present a potentially lethal occupational hazard. We call for implementation of monitoring programs to further address the conservation implications of this large‐scale marine reptile exploitation. Cosecha de Serpientes Marinas en el Golfo de Tailandia  相似文献   

16.
设置0、0.001、0.01、0.1、l和10mg·L-16个质量浓度梯度,测定了草甘膦异丙胺盐(Glyphosate—isopropylammonium)农药对球形棕囊藻(Phaeocystis globosa)生长、叶绿素a含量、SOD和CAT活性的影响,探讨了有机磷农药对球形棕囊藻的毒物刺激效应。结果表明,低浓度的草甘膦异丙胺盐对球形棕囊藻的生长呈现出刺激效应。在实验所设定的6个质量浓度梯度范围内,0.001mg·L0和0.01mg·L-1质量浓度处理下的刺激效应最为显著。该两个质量浓度处理下,球形棕囊藻的平均相对增长率比对照分别提高了1.27%和0.45%,叶绿素a含量分别比对照提高了9.2%和2.5%,SOD活性提高了5.9%和7.2%,CAT活性提高了93%和155%;而当草甘膦异丙胺盐质量浓度在0.1mg·L-1以上时,球形棕囊藻的生长率、叶绿素a含量、SOD活性均显著低于对照。草甘膦异丙胺盐在0.001mg·L-1和0.01mg·L-1范围内对球形棕囊藻均呈现刺激效应,而高于0.1mg·L-1时球形棕囊藻各生理指标表现出显著抑制效应。研究结果为了解有机磷农药对海洋微藻生长的影响特征,揭示有机磷农药对微藻产生低促高抑的规律和为深入探索赤潮暴发的成因提供依据。  相似文献   

17.
Antibiotics are used widely in human and veterinary medicine, and are ubiquitous in environment matrices worldwide. Due to their consumption, excretion, and persistence, antibiotics are disseminated mostly via direct and indirect emissions such as excrements, sewage irrigation, and sludge compost and enter the soil and impact negatively the natural ecosystem of soil. Most antibiotics are amphiphilic or amphoteric and ionize. A non-polar core combined with polar functional moieties makes up numerous antibiotic molecules. Because of various molecule structures, physicochemical properties vary widely among antibiotic compounds. Sorption is an important process for the environment behaviors and fate of antibiotics in soil environment. The adsorption process has decisive role for the environmental behaviors and the ultimate fates of antibiotics in soil. Multiply physicochemical properties of antibiotics induce the large variations of their adsorption behaviors. In addition, factors of soil environment such as the pH, ionic strength, metal ions, and organic matter content also strongly impact the adsorption processes of antibiotics. Review about adsorption of antibiotics on soil can provide a fresh insight into understanding the antibiotic-soil interactions. Therefore, literatures about the adsorption mechanisms of antibiotics in soil environment and the effects of environment factors on adsorption behaviors of antibiotics in soil are reviewed and discussed systematically in this review.  相似文献   

18.
为了解不同浓度铜(Cu)、锌(Zn)重金属污染土壤对乔木抗氧化指标的影响以及为植物修复蠡河重金属污染岸带提供理论依据,选取广玉兰(Magnoliagrandiflora)、香樟(Cinnamomumcamphora)、榉树(Zelkovaschneideriana)幼苗,采用土培法浇灌重金属溶液模拟土壤污染环境,研究不同浓度重金属Cu/Zn对乔木脯氨酸含量、过氧化物酶活性、过氧化氢酶活性及丙二醛含量的单一及复合影响。实验表明,单一Cu胁迫对广玉兰、香樟和榉树的毒害作用较单一,Zn胁迫严重;Cu/Zn复合作用下,3种乔木抗氧化指标均在Cu15和Zn110时达到最大值,表现出较强的抗性,而后随着复合作用强度增加,重金属对其毒害作用增大;75μg/gCu和210μg/gZn单一及复合胁迫时,广玉兰丙二醛含量相对香樟和榉树较接近对照值,过氧化物酶和过氧化氢酶活性较大,脯氨酸含量差别不大。综合分析,不同乔木在不同浓度重金属胁迫下抗氧化指标作出不同响应,广玉兰对高浓度Cu/Zn胁迫不敏感,承受能力和抗性较强,适合于修复Cu/Zn污染较严重土壤。  相似文献   

19.
退化滨水景观带植物群落生态修复技术研究进展   总被引:8,自引:0,他引:8  
滨水带是重要的生态交错带,物质、养分和能量流动速率高,具有较高的生态、经济和美学价值。近年来,由于缺乏科学合理的生态规划意识,我国滨水带多被建成近直立人工护岸,加之自然、人为干扰力度的加强,滨水岸线生境破坏,生物群落丧失,滨水带退化,水岸生态环境日趋恶化。通过对滨水带生态景观功能分析,研究滨水带退化原因与机理,系统归纳了国内外退化滨水景观带植物群落生态修复相关技术的研究现状,深入探讨了生境恢复、生物廊道恢复、景观格局美化和水岸生态系统结构与功能优化等方面的研究内容,并提出今后滨水带生态修复技术研究方向,以及基于生态学、景观学、水力学、土力学、生物学、经济学等多学科背景的滨水景观带植物群落定量分析、配置方法。最后指出,滨水景观带植物群落生态修复技术研究需进一步分析我国水岸生态系统退化机理、细化滨水深槽-浅滩序列、量化滨水植被配置宽度与生物多样性关系、深化稳定化长效管理技术等,为我国退化滨水生态景观带植物群落生态修复集成技术的研究与实践提供参考,以全面有效的提高生态环境质量。  相似文献   

20.
ABSTRACT

The application of a sustainable tourism management and development framework, including the enhancement of cultural heritage is presented for the city of Nafpaktos (Western Greece) and the surrounding area. Through a qualitative SWOT analysis and a quantitative Limits of Acceptable Change (LAC)–Tourism Carrying Capacity (TCC) framework, an attempt is made to establish thresholds, monitor current conditions, and upgrade tourism activities, with simultaneous development of the tourism-associated economic sectors and the cultural heritage of the city. Activity zones are identified and 18 indicators are selected to describe the environmental/cultural, economic, and social conditions of the area. Reference conditions for each indicator are established either as measured or negotiated thresholds and indicators are accordingly scored to depict the current divergence from reference. The Leopold matrix is used to compare scores and identify restrictions of development. Results reveal high potential for sustainable tourism development of the area, as 9 of 18 indicators received high scores, indicating sustainable conditions, and a variety of underdeveloped tourism endpoints were identified, including the castle of the city, which could potentially support a 90-fold increase in tourism flow. However, restricting factors of development were detected, related to the lack of a tourism management plan, the weak on-site protection of the natural and cultural heritage and the lack of awareness for sustainability among the local people. A strategic plan is finally proposed to provide managers, stakeholders, and the local communities with a guiding framework to upgrade the tourism flow in and around the city within a step-by-step sustainable process.  相似文献   

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