共查询到20条相似文献，搜索用时 109 毫秒
1.
Md. Saiful ISLAM Md. Kawser AHMED Md. Habibullah Al-MAMUN Dennis Wayne EATON 《土壤圈》2020,30(2):201-213
Trace metal contamination in soil is of great concern owing to its long persistence in the environment and toxicity to humans and other organisms.Concentrations of six potentially toxic trace metals,Cr,Ni,Cu,As,Cd,and Pb,in urban soils were measured in Dhaka City,Bangladesh.Soils from different land-use types,namely,agricultural field,park,playground,petrol station,metal workshop,brick field,burning sites,disposal sites of household waste,garment waste,electronic waste,and tannery wast,and construction waste demolishing sites,were investigated.The concentration ranges of Cr,Ni,Cu,As,Pb,and Cd in soils were 2.4–1258,8.3–1044,9.7–823,8.7–277,1.8–80,and 13–842 mg kg^-1,respectively.The concentrations of metals were subsequently used to establish hazard quotients(HQs)for the adult population.The metal HQs decreased in the order of As>Cr>Pb>Cd>Ni>Cu.Ingestion was the most vital exposure pathway of studied metals from soils followed by dermal contact and inhalation.The range of pollution load index(PLI)was 0.96–17,indicating severe contamination of soil by trace metals.Considering the comprehensive potential ecological risk(PER),soils from all land-use types showed considerable to very high ecological risks.The findings of this study revealed that in the urban area studied,soils of some land-use types were severely contaminated with trace metals.Thus,it is suggested that more attention should be paid to the potential health risks to the local inhabitants and ecological risk to the surrounding ecosystems. 相似文献
2.
3.
Iron and steel slags are smelting wastes, mainly including blast furnace slag(BFS) and steel slag(SS) produced in the iron and steel industry. Utilization of iron and steel slags as resources for solving the problem of slag disposals has attracted much attention with increasing iron and steel smelting slags in China. Because the iron and steel slags contain calcium(Ca), magnesium(Mg), phosphorus(P), and silicon(Si), some have tried to use them as Si-and P-fertilizers, for producing Ca-Mg-P fertilizers, or as soil amendments in agriculture. However, in the iron metallurgical process, several pollutants in iron ores can inevitably transfer into iron and steel slags, resulting in the enrichment of pollutants both in BFS(mainly nickel(Ni), copper(Cu), mercury, zinc(Zn),cadmium(Cd), chromium(Cr), arsenic, lead, selenium, fluorine(F), and chlorine(Cl)) and in SS(mainly Ni, Cr, Cd, Zn, Cu, F, and Cl), in which some of pollutants(especially Cr, Ni, F, and Cl) exceed the limits of environmental quality standards for soils and groundwater. The elements of manganese, barium,and vanadium in iron and steel slags are higher than the background values of soil environment. In order to ensure soil health, food safety, and environmental quality, it is suggested that those industrial solid wastes, such as iron and steel slags, without any pretreatment for reducing harmful pollutants and with environmental safety risk, should not be allowed to use for soil remediation or conditioning directly in farmlands by solid waste disposal methods, to prevent pollutants from entering food chain and harming human health. 相似文献
4.
《山西水土保持科技》2010,(3):11-11
<正>淤地坝管护经费落实后,如何用好这笔经费,各地结合自身实际情况制定了相应的使用办法。临汾市隰县实行百分考核制,逐项量化打分,奖优罚劣,不搞平均分配,强化了管护人员的安全责任。他们的具体做法:一是对责任心不强,致使管护范围内放牧,毁坏林木,损坏淤地坝工程设施,未按时间上坝巡查,或者情况掌握不准,迟报、漏报、瞒报汛情,卧管孔塞丢失、缺损,坝体塌陷、冲沟不修补,排水设施淤积不清理,管护责任人将受到处罚,情节严重的,解除合同,并追究行政负责人的责任。 相似文献
5.
6.
7.
(一)一般介绍 博斯腾湖位于新疆焉耆盆地中心,焉耆盆地据过去自然区域之划分,属于北山系中的山间盆地,四周为高山所环绕,在气候上不受海洋气团之影响,其特征是夏季气温高,湿度小,风速大,蒸发量一般为降水量的38倍左右,与塔里木盆地很相似,可以说是塔里木盆地的缩影。焉耆盆地从高山到低地,在地貌上大概可以这样划分:①高山带:以古生代之千枚岩,花岗岩,硬砂岩,石英岩,板岩,斑岩等为主。②山麓砾石带:因为在第三纪湖相盆地水份干涸后,那时气候非常干燥,童山濯濯,森林分布稀少,促进了岩石 相似文献
8.
Debasis MITRA Rittick MONDAL Bahman KHOSHRU Ansuman SENAPATI T. K. RADHA Bhaswatimayee MAHAKUR Navendra UNIYAL Ei Mon MYO Hanane BOUTAJ Beatriz Elena GUERRA SIERRA Periyasamy PANNEERSELVAM Arakalagud Nanjundaiah GANESHAMURTHY Sne&#;ana AN&#;ELKOVI&#; Tanja VASI&#; Anju RANI Subhadeep DUTTA Pradeep K. DAS MOHAPATRA 《土壤圈》2022,32(1):149-170
Agricultural areas of land are deteriorating every day owing to population increase, rapid urbanization, and industrialization. To feed today’s huge populations, increased crop production is required from smaller areas, which warrants the continuous application of high doses of inorganic fertilizers to agricultural land. These cause damage to soil health and, therefore, nutrient imbalance conditions in arable soils. Under these conditions, the benefits of microbial inoculants (such as Actinobacteria) as replacements for harmful chemicals and promoting ecofriendly sustainable farming practices have been made clear through recent technological advances. There are multifunctional traits involved in the production of different types of bioactive compounds responsible for plant growth promotion, and the biocontrol of phytopathogens has reduced the use of chemical fertilizers and pesticides. There are some well-known groups of nitrogen-fixing Actinobacteria, such as Frankia, which undergo mutualism with plants and offer enhanced symbiotic trade-offs.In addition to nitrogen fixation, increasing availability of major plant nutrients in soil due to the solubilization of immobilized forms of phosphorus and potassium compounds, production of phytohormones, such as indole-3-acetic acid, indole-3-pyruvic acid, gibberellins, and cytokinins, improving organic matter decomposition by releasing cellulases, xylanase, glucanases, lipases, and proteases, and suppression of soil-borne pathogens by the production of siderophores, ammonia, hydrogen cyanide, and chitinase are important features of Actinobacteria useful for combating biotic and abiotic stresses in plants.The positive influence of Actinobacteria on soil fertility and plant health has motivated us to compile this review of important findings associated with sustaining plant productivity in the long run. 相似文献
9.
10.
本文是《广西壮族自治区畜禽寄生虫名录》的补遗与修订 ,收载了广西畜禽体内外寄生虫共计 51 8种 ,隶属于 7门 ,1 0纲 ,2 5目。它们包括 :鞭毛虫 2科 ,2属 ,2种 ;类锥体虫 2科 ,4属 ,4 6种 ;无类锥体虫 2科 ,2属 ,4种 ;纤毛虫 1科 ,1属 ,1种 ;吸虫 1 6科 ,38属 ,95种 ;绦虫 6科 ,2 4属 ,4 2种 ;线虫30科 ,65属 ,1 36种 ,棘头虫 3科 ,3属 ,5种 ;蜱螨 7科 ,1 3属 ,2 5种 ;昆虫 1 9科 ,38属 ,1 62种 相似文献
11.
针对校园网的流量问题,在网关型设备的基础上,在校园网中采用基于应用层的网络流量控制方法,并对校园网流量控制策略采取了精细化的分类,为解决校园网出口瓶颈问题提出了新的思路。 相似文献
12.
从“人人网”的发展与特点入手，介绍了校园SNS对学生的思想导向作用，从实践的角度探究了高校网上建团的思路与舆情引导的关系，提出开展网络思想政治教育的新思路。 相似文献
13.
OSPF协议作为一种在大型网络中运行的协议很适合在高校校园网络中运行,OSPF协议的配置是否合理直接决定了校园网络的运行是否稳定。从宝鸡文理学院校园网络的现状出发,结合其改造工程实例,从OSPF原理开始论述并探讨了OSPF在校园网部署中的区域划分、路由优化等问题。 相似文献
14.
在介绍VPN相关知识的基础上,结合IPSec VPN与SSL VPN各自的优缺点,提出了针对校园网的不同需求,采用不同模式的校园网VPN技术,选择适合校园网应用的最佳模型,并对VPN技术在校园网中的应用前景进行了展望。 相似文献
15.
本文简述了虚拟专用网技术在高校校园网的应用,并结合实际应用情况详细阐述了如何在Linux系统中架设基于PPTP的VPN服务器,解决了校外老师访问校园网资源速度缓慢的具体问题。 相似文献
16.
17.
本文介绍了基于策略路由的双出口校园网的实现，理论联系实际进行了分析、配置，较好地解决了混合IP组网的校园网用户访问INTERNET的问题。 相似文献
18.
随着高校校园网规模的不断扩大,以及应用的不断深入,校园网的安全问题也日益突出。本文在对校园网的安全特点和安全问题分析的基础上,提出了加强对校园网安全建设的对策。 相似文献
19.
大学校园从单纯教学功能迈向多元化,校园外部环境设计也随之不断演变发展。本文以重庆工商职业学院合川校区外部环境景观设计为例,从山地校园景观结构布局、文化内涵的表达、特色景观塑造的角度详细阐述,对山地校园景观构建作多维度的实践探索。 相似文献
20.
数字化校园建设是网络环境下高等教育适应信息社会的需求,也是实现自身与社会不断发展进化的必然选择。教育信息化作为高校建设的重要组成部分,数字化校园建设是其根本目标。目前,由于思想观念落后、缺乏有效的管理机制使得数字化校园建设无法取得应有的效益,通过对甘肃省11所高校数字化校园建设进行调研,对数字化校园建设的现状进行了分析,并提出具体的对策与建议。 相似文献