滇池内湖滨带重金属污染及其生态风险评价

水体沉积物是重金属元素的重要载体,其含量高低能反映水环境质量现状。采集滇池内湖滨带沉积物样品,分析了滇池内湖滨带表层沉积物中Pb、Cd、Cu、Zn、Cr、Ni、Fe、Mn 8种重金属元素含量特征,并用Hakanson潜在生态危害指数法评价其生态危害,旨在为合理预防和治理滇池内湖滨带的重金属污染以及内湖滨带生态系统的修复提供基础资料。结果表明,与“全国土壤环境质量标准”对比,表层沉积物中主要是Cd、Cu、Zn超标,重金属污染强度总体上是草海＞外海。不同重金属间的相关性分析结果表明,Cu-Cd之间呈极显著相关,说明这两种元素污染源可能相同,几种污染重金属与胶体矿物元素Fe、Mn间的相关性不大,说明在所调查沉积物中,Fe/Mn氧化物或氢氧化物共沉淀或吸附Pb、Cd、Cu、Zn、Cr、Ni元素量较少。由潜在生态风险评价结果可知,滇池内湖滨带表层沉积物已具极强生态危害,各重金属对滇池内湖滨带生态风险影响程度由高到低依次为：Cd〉Cu〉Pb〉Ni〉Zn≈Cr。     

昆承湖沉积物重金属的环境地球化学特征

对昆承湖9个采样点柱状沉积物中主要重金属元素(Pb,Cu,Zn,Cd,Cr)的垂向分布进行了测定,结果表明,5种重金属元素具有非常相似的垂向变化特征,表现为随沉积深度增加含量降低的态势;横向上表现为靠近污染源的含量高,远离污染源的含量低。各重金属元素均与TOC之间呈显著正相关关系,表明沉积物中重金属污染受人类活动作用较为明显。地积累指数评价结果显示,Zn污染最重,且污染主要集中在表层;潜在生态风险性指数反映出全湖沉积物中的重金属污染属于中等生态危害程度,Cd是最主要的生态危害元素;生物毒性效应评价则表明目前昆承湖沉积物的金属毒性效应不高,但各样点的ΣTUs都表现为由底层向表层逐渐增大的态势,必须予以相当的重视,避免加重该湖的生物毒性。     

昆承湖沉积物重金属的环境地球化学特征

对昆承湖9个采样点柱状沉积物中主要重金属元素（Pb,Cu,Zn,Cd,Cr）的垂向分布进行了测定,结果表明,5种重金属元素具有非常相似的垂向变化特征,表现为随沉积深度增加含量降低的态势;横向上表现为靠近污染源的含量高,远离污染源的含量低。各重金属元素均与TOC之间呈显著正相关关系,表明沉积物中重金属污染受人类活动作用较为明显。地积累指数评价结果显示,Zn污染最重,且污染主要集中在表层;潜在生态风险性指数反映出全湖沉积物中的重金属污染属于中等生态危害程度,Cd是最主要的生态危害元素;生物毒性效应评价则表明目前昆承湖沉积物的金属毒性效应不高,但各样点的∑TUs都表现为由底层向表层逐渐增大的态势,必须予以相当的重视,避免加重该湖的生物毒性。     

巢湖表层沉积物中重金属污染的时空变化特征及潜在生态风险评价

2008年3月至7月连续对巢湖8个采样点的表层沉积物中Zn、Hg、Cr、Pb、Ni和Cu6种重金属含量进行分析,据此探讨巢湖表层沉积物中重金属污染程度及时空分布特征,评价巢湖重金属污染的潜在生态风险并筛选出主要生态风险因子。结果表明：3月至7月期间,全湖范围内表层沉积物中重金属含量逐渐降低,河流入湖区的污染程度高于其他区域,Zn、Cu、Pb的污染程度高于其他重金属,表层12cm沉积物中的重金属含量随深度增加污染情况呈加重趋势;从潜在生态风险角度分析,巢湖表层沉积物总体只具有轻微潜在生态风险,生态风险指数排名前两位的区域是南淝河入湖区和十五里河入湖区,3月至7月期间重金属潜在生态风险级别逐渐降低,巢湖生态安全主要风险因子为Hg,其次是Pb和Cu。     

大沽河湿地表层沉积物重金属分布特征及污染评价

胶州湾属半封闭海湾,水体交换能力较弱,受多条河流入海影响,污染日趋加重,通过大沽河的径流量、输沙量和溶解污染物占到胶州湾入海河流的首位。根据区域特征,于2009年2、5、8、11月对大沽河湿地48个采样点表层沉积物中的Cu、Zn、Pb、Cd、Hg、As、有机碳、粒度进行测定,探讨了重金属含量和污染特征与总有机碳、粒度的关系,利用污染评价法和潜在生态风险评价法进行污染和风险分析。结果表明：胶州湾大沽河湿地表层沉积物重金属含量较低,大部分测站符合海洋沉积物质量（GB 18668—2002）Ⅰ类标准的要求。表层沉积物中Cu、Pb、Zn含量8月份最高、2月份次之、5月份最低。Pb、Hg、As 3种重金属含量在2月份最高。Cu、Pb、Zn和Cd重金属之间存在显著正相关关系,Hg与As存在明显的相关关系;除Cd和As外的4种重金属与沉积物粘土、有机碳含量之间也存在显著正相关性。重金属单因子污染程度总体较轻,属于低污染水平,污染程度依次为Hg〉Cd〉Pb〉Cu〉As〉Zn。大沽河河口区表层沉积物重金属潜在生态风险总体处于较低水平,风险程度依次为Hg〉Cd〉Pb〉Cu〉As〉Zn。     

渭河中下游河道沉积物重金属污染生态风险评价

以渭河中下游河道沉积物为研究对象,在分析12个干流采样点和7个一级支流采样点沉积物中Pb,Zn,Cr,Cu,Co和Ni六种重金属元素含量变化的基础上,采用Hakanson潜在生态风险指数法对河道沉积物重金属污染的生态风险程度进行了评价。渭河中下游河道19个采样点沉积物中Pb,Zn,Cr,Cu,Co和Ni六种重金属元素含量均不同程度超过了陕西省土壤重金属背景值,除Pb外,支流沉积物中其他五种重金属的平均含量都低于干流沉积物;Hakanson潜在生态风险评价结果显示,渭河中下游采样点的六种重金属元素单项生态风险指数均小于40,综合潜在生态风险指数均小于50,潜在生态风险处于较低水平,表明渭河中下游河道沉积物中重金属富集量小,基本不构成生态风险。     

上海市老港垃圾填埋场潮滩重金属污染及评价研究

以上海市老港垃圾填埋场潮滩为例,研究了沉积物中重金属的分布特征,并采用化学法和潜在生态危害指数法评价了潮滩重金属的污染状况及其潜在生态危害,以期为保护潮滩环境以及利用潮滩进行垃圾渗滤液的净化提供科学依据。结果表明,受垃圾渗滤液排放和生物活动影响,老港潮滩表层沉积物中重金属(除Cu外)的含量在向海向上均表现为:高潮滩>低潮滩>中潮滩;Cr和Zn的含量在氧化池排污口处明显高于其它排污口,而Pb的含量在自然排污口处最高;老港潮滩沉积物受到一定程度的重金属污染,以Zn的污染最为严重,由这4种元素造成的潜在生态危害是中等的,其中,Cu和Pb的毒性贡献最大。     

福建闽江河口湿地土壤重金属污染特征及评价研究

为掌握福建闽江河口湿地重金属污染特征,对闽江河口湿地不同监测点重金属污染状况进行全面调查采样,利用综合污染指数法和地累积指数法对重金属污染状况进行评价。结果表明,福建闽江河口湿地重金属污染比较严重,除Ni和Cr外,Cu、Pb、Zn、Cd、Mn均超过土壤环境质量标准（I级）。除Ni和Cr单项污染指数无污染外,其他监测点均有不同程度的重金属污染,污染程度表现为Pb〉Cu〉Zn〉Cd;综合污染指数除潭头港和鳝鱼滩为轻度污染,其他6个监测点均达到中度污染以上,表明闽江河口湿地存在严重的重金属复合污染。地累积指数除Pb、Zn、Cd污染达到中或轻度污染水平,其他重金属均无污染。     

重庆市长寿湖重金属污染评价

中国环境科学研究院采集了长寿湖沉积物样品,分析其表层沉积物中Pb、Cd、Cu、Zn、Cr、Ni、Hg、As 8种重金属元素含量特征,结果表明,按照《土壤环境质量标准》,目前长寿湖主要是Cd、Hg和As的污染,且中部湖区沉积物重金属污染强度要高于东部和西部两区。各重金属间的相关性分析表明,Cu-Zn、Cu-Ni、Zn-Ni之间呈极显著相关,说明这3种元素污染源可能相同。由潜在生态风险评价结果可知,长寿湖重金属污染只是略超轻微生态危害,各重金属对长寿湖生态风险影响程度由高到低依次为：Hg〉Cd〉As〉Pb〉Ni〉Cu〉Cr〉Zn。应用Hakanson潜在生态危害指数法评价其生态风险,并提出了相关污染防治措施,为预防和综合治理长寿湖提供了科学依据。     

滇池沉积物中重金属的形态分布特征

本文利用BCR三步提取法对滇池沉积物中的重金属(Cd、Cr、Cu、Pb和Zn)形态进行了详细研究.结果表明,表层沉积物中的Cd和Zn主要以可提取态(即弱酸溶解态、可还原态和可氧化态)存在,其中,Cd在弱酸溶解态、可还原态和可氧化态中的含量分别为35.0%、49.7%和12.9%;Zn在三者中的含量也分别达到了17.6%、16.6%和21.4%.而Cr、Cu和Pb主要以残渣态存在,其含量分别为88.5%、59.2%和81.8%.表层沉积物中可提取态重金属的空间分布特征为草海含量最高,其次为外海北部和南部,开阔湖中心区域含量最低.除Cr和Cu外,其他可提取态重金属的总含量随着采样深度的增加而减少.     

论图书馆数字馆藏资源建设中亟待解决的问题

论述数字馆藏的产生、概念和特点,分析数字馆藏资源建设中存在的问题,探讨数字馆藏资源建设中应采取的策略。     

Transformation of the Bryansk Paleosol in Microdepressions in the Center of the East European Forest-Steppe during the Maximum of Valdai Glaciation and in the Holocene

Eurasian Soil Science - Recent and Late Pleistocene soils of the central forest-steppe in the East European Plain have been studied. The main objective of the work is to reveal changes in the...     

Changes in the structure of the rhizosphere complex of actinomycetes in the ontogenesis of winter rye

Changes in the taxonomic structure of actinomycetes in the rhizosphere of winter rye (Secale cereale L.) growing on acid soddy-podzolic soil were studied. During the first stages of ontogenesis of winter rye, the rhizosphere complex of mycelial prokaryotes was characterized by a relatively level generic structure (with respect to the indices of abundance and frequency of particular genera), low values of the species diversity, and low domination frequency of the species from the Streptomyces genus. The numbers and species diversity of the streptomycetes increased during the further growth of the winter rye, so that streptomycetes became a dominant group in the complex of the rhizosphere actinomycetes. According to the two-way ANOVA, the population density of the Micromonospora and the Streptosporangium genera in the rhizosphere was mainly dictated by the winter rye variety, whereas the population density of the streptomycetes depended on the particular stage of the winter rye development. The differences between the actinomycetal complexes characteristic of different varieties of winter rye at the early stages of its development was leveled by the end of the winter rye growth.     

Variations in the composition of the sap of zea mays with the increase in osmotic pressure of the nutritive solution

The alterations are studied which are produced in the content of mineral elements and organic fractions of sap with the increase in the osmotic pressure of the nutritive solution at levels of 2.0; 3.5 and 5.0 atm., obtained through the addition to the nutritive solution either of magnesium sulphate or PEG‐4000.

Through the effect of the osmotic pressure, the transformations are modified of the nitrogen and mineral phosphorus at organic fractions experience a series of modifications which produce different values in the Nm%TSN and Pm%TSP ratios with respect to control. Through action of the specific effect of magnesium sulphate, the reducing sugars concentrations in sap having an important increase.     

稳定同位素在植物源性农产品产地溯源研究进展

产地溯源是保护农产品品牌及地区特色产品、防止欺诈、保护消费者权益的有效保障。稳定同位素指纹分析是用于食品产地溯源的有效技术之一,具有高效、准确、可靠的特点。本文系统分析了近5年来,稳定同位素指纹分析技术在植物源性初级农产品、加工农产品溯源中的应用以及稳定同位素在食品加工过程中分馏变化的研究进展。在此基础上,展望了今后稳定同位素在植物源性农产品产地溯源中的研究重点和发展方向。     

Evolution of forest pedogenesis in the south of the forest-steppe of the Central Russian Upland in the Late Holocene

The Late Holocene stage of forest pedogenesis has been studied on the interfluves along river valleys in the forest-steppe zone of the Central Russian Upland. The development of gray forest soils from the former chernozems as a result of the Late Holocene advance of forest vegetation over steppes is discussed. It is argued that the climatic conditions of the Subatlantic period were unstable, so that multiple alternation of forest and steppe vegetation communities took place. This specified a complex character of soil evolution upon contrasting substitution of forest pedogenesis for steppe pedogenesis. On the interfluves near the natural drainage network (balkas, ravines, and steep slopes of river valleys), the climate-driven dynamics of forest and steppe vegetation with corresponding changes in the character of pedogenesis could take place during the entire Holocene, which is reflected in a lower thickness of humus profiles and deeper leaching of carbonates from chernozems of the Early Iron Age in comparison with their analogues formed under steppe cenoses in central parts of the interfluves. Two variants of the evolution of gray forest soils can be suggested: the pulsating evolution typical of balkas and interfluves near river valleys and the continuous progressive evolution typical of automorphic (plakor) positions in central parts of the interfluves.     

Accumulation of chemical elements in the raised peatbogs of the subtaiga Trans-Urals in the Holocene

The results of studying the variability of the geochemical parameters of the layers of the Sartamskii upland peatbog in the south of Tyumen oblast based on the radiocarbon time scale are given. Four basic types of peat and stages of peat deposits formation in the Holocene are distinguished: the organomineral layer of the sediments in a paleolake (up to 5065 ± 60 years ago), the low moor layer (4300–4900 years ago), the transitional layer (3100–4300 years ago), and the high moor peat (250–3100 years ago). The upper peat layer (last 200–300 years) significantly differs from its main portion; in particular, it is characterized by an increased ash content and the accumulation of a number of elements. The relationship between the various characteristics of the deposit is analyzed using principal component analysis, and the conditions of the formation of the peat deposit in different time periods are estimated, including the climatic conditions (in relative units). The anthropogenic signal of the accumulation of some elements in wetland systems is identified.     

Seasonal changes in the communities of microorganisms and algae in the litters of tree plantations in the steppe zone

Specific structural and dynamic parameters of communities from various ecological and trophic groups of microorganisms and algae in the litter of artificial tree stands were studied using the example of the Staro-Berdyansky Forest in the steppe zone of Ukraine. The composition of the communities was shown to vary by seasons and depend on the forest-forming woody species. In spring, in all the litters, the maximal number of actinomycetes and aminotrophs was recorded; in the leaf litter, the number of phosphate-mobilizing organisms was also the largest. In summer, the development of cellulolytic organisms, ammonifiers, and nitrogen-fixers was intensified; in autumn, the number of micromycetes and oligotrophic organisms decreased. The composition of dominants, the species richness of algae and their abundance also varied by seasons. Representatives of the Chlorophyta division predominated. The highest species richness of algae was characteristic of the spring litter samples, and their number, for the spring and autumn ones. The positive correlation was established between the numbers of micromycetes and oligotrophs, micromycetes and algae. The negative correlation was found between the numbers of micromycetes and actinomycetes, cellulose-decompose bacteria and algae in the litters.     

植树造林在黄河三角洲生态与环境建设中的作用

通过认真分析黄河三角洲生态环境的现状和存在的问题，探讨了林业在黄河三角洲生态环境建设中的作用，并结合黄河三角洲的实际情况，从森林生态体系建设的角度，提出了黄河三角洲生态环境建设的对策，为黄河三角洲生态建设和可持续发展提供科学依据。