Human and ecological risks of metals in soils under different land-use types in an urban environment of Bangladesh

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.     

青花菜品种在南亚热带地区的适宜性研究

青花菜又称绿叶菜,原产于地中海沿岸,其特点是营养价值高,含有多种矿物质等营养,位居同类蔬菜之首。由于青花菜生育期短,耐寒性强,主要产区在北方,在南方只有冷凉地区有少量栽培,而贵州属典型的南亚热气候类型,特别是在罗甸地区,秋季作物收获后,冬季只种植一些白菜类蔬菜。而营养价值高的青花菜,     

Environmental risks for application of iron and steel slags in soils in China: A review

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.     

隰县百分制强化淤地坝管护责任

<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。     

呼和浩特市依托水土保持生态建设促进生态旅游成效显著

近10年来,内蒙古呼和浩特市通过抓重点,建精品,搞示范,有效地带动了全市水土保持生态建设全面,快速地发展,现水土流失累计治理程度达48%,累计投入达2.6亿元,在治理过程中,利用资源优势,积极发展生态旅游,以开发促治理,拓展了水土保持生态建设领域。     

编委风采

陈文俊陈文俊,男,1965年生,汉族,重庆合川人,中共党员,在职博士,研究员,中国作物学会、中国遗传学会会员,重庆市首届有突出贡献的中青专家。参     

新疆博斯腾湖地区盐土生成类型和地下水的关系

(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     

Actinobacteria-enhanced plant growth, nutrient acquisition, and crop protection: Advances in soil, plant, and microbial multifactorial interactions

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.     

《广西壮族自治区畜禽寄生虫名录》补遗与修订(Ⅱ)

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     

绿荫鲜花扮美东京都

日本首都东京,是世界上屈指可数的人口超千万的特大型城市。在我的想象中,那里必定是高楼大厦鳞次栉比,到处车水马龙,绿树稀疏。然而,不久前的一次东京之行,我惊奇地发现,东京的繁华中充满勃勃生机,整座城市绿化得非常好,给人一种清新的感觉。     

对于Bentonite之初步研究

民国三十三年著者以英国奖学金,由农林部派赴英国剑桥大学研究,三十五年在剑桥 Gan-vendish 实验室膠质化学部研究土壤膠质,蒙 Rideal 教授予以种种方便,并嘱研究 Bentonite,惟研究之时间甚短,疏忽错误之处,尚希读者惠予指正为幸。Montmorillonite(Mg,CaO,K,Na)Al_2O_3·5 SiO_2 5H2O 土,为构成 Bentonite 之主要成分,可以代表土壤无机膠质吸持养分及供给养分于植物之机能,又可藉此而说明土壤之主要理化学性质。以 X—ray 分析 Bentonite,其所示之光带,相当于 Montmorillonite 与石英适量之混合物,故由 Bentonite 试验所得之结果,亦可以作研究土壤膠质性能之参考。     

地形因子与土壤养分空间分布的相关性研究

运用地统计学和GIS技术,研究丘陵地区土壤养分的空间变异性,探讨地形因子对土壤养分含量空间分布的影响.结果表明:N,K的空间变异主要来自随机因素,而Mg及其他养分的空间变异性在一定程度上受地形等结构性因素的影响.OM,N,P,K几种大量元素与海拔呈显著正相关,Ca,Mg,S与海拔呈负相关;N与坡度呈显著正相关,Ca与坡度呈显著负相关;OM,N,P与坡向呈负相关,Ca,Mg与坡向呈显著正相关关系;而K,S与地形因子的相关性不显著.研究地形地貌与土壤养分之间的空间关系,为进一步合理进行土地利用规划提供理论依据,并且对土壤养分综合管理以及进行土壤改良和耕作都具有一定的指导作用.     

四月日本赏樱花

日本工友这样向我说:"在日本,你不会欣赏樱花,连追求你的帅哥都没有。"这话也不是没有道理,在日本工作期间,日历一翻到4月,人们茶余饭后谈论的话题就是樱花,日本人全民爱樱花,全民是樱花迷。谈起樱花,人们眉飞色舞、津津乐道。生活在这样的氛围中,你要是真不懂樱花,不会欣赏樱     

小叶女贞盆景的制作(一)繁殖

小叶女贞(Ligustrum quihoui Carr.)是木犀科女贞属的落叶或半常绿灌木,别名小叶冬青、小叶水蜡树、小白蜡、楝青。叶小,对生,具光泽,凌冬青翠,6—7月开白花,11—12月果熟,可采摘播种。病虫害较少,能减低噪音,吸收二氧化硫等有害气体。喜阳光,稍耐阴,耐寒性极强。可植作树丛,配于草坪一隅;也可用作绿篱,是庭院风景树良材。因其叶小,萌芽力强,耐     

山东沿海盐土荒地的改良利用问题

山东半岛北翼渤海湾内,主由黄河入海时沉积物所成的三角洲地带,占面积约四百万亩以上的荒地,即所谓“苦海盐边”的荒凉地区,抗日战争期间这里曾作过抗日根据地,因此这种荒地的开发及利用,将带动老根据地人民走向集体化生产。但本区土壤多为盐质冲积土,盐分较多,利用适当将日趋改善,否则仍可因耕作不良导致不良后果,本文就观察所得略作讨论。     

秧田泡青的试验报告和讨论

一、序言将青嫩的植物茎叶(以冬作荳类为主)泡在水稻秧田里,让它腐解产生肥效,称为秧田泡青。这方法,在长江中游,有不少地方实施着,但是,由于过去农村间相互闭塞,这些点的经验没有广为推行。我们认为这是一种优良的农业技术,经过适当的实验研究,在长江流域和长江以南可以普遍推广。1944年,前中央农业实验所在     

河西走廊水资源利用与生态环境建设的几点思考

河西走廊是甘肃重要的商品粮、蔬菜、果品生产基地 ,水利为河西走廊经济社会的快速发展提供了有力的支撑和保障。但是 ,河西走廊地区水资源供需矛盾突出、配置不尽合理 ,地下水位急剧下降 ,生态环境恶化趋势加剧 ,节水措施不力 ,水的利用效率不高 ,水资源统一管理薄弱。因此 ,要加快立法 ,调整经济结构 ,优化配置水资源 ,保证生态用水适度发展经济 ,加强水资源统一管理 ,改革用水管理制度 ,加强综合治理等     

编委风采

高立洪,男,1970年10月出生,重庆垫江县人,高级工程师,中共党员。1994年7月毕业于西南大学,现任重庆市农业科学院农业工程研究所所长、党支部书记,重庆市生     

Importance of hydrogenotrophic, aceticlastic and methylotrophic methanogenesis for methane production in terrestrial, aquatic and other anoxic environments: A mini review

Microbial methanogenesis is a major source of the greenhouse gas methane(CH4).It is the final step in the anaerobic degradation of organic matter when inorganic electron acceptors such as nitrate,ferric iron,or sulfate have been depleted.Knowledge of this degradation pathway is important for the creation of mechanistic models,prediction of future CH4 emission scenarios,and development of mitigation strategies.In most anoxic environments,CH4 is produced from either acetate(aceticlastic methanogenesis)or hydrogen(H2)plus carbon dioxide(CO2)(hydrogenotrophic methanogenesis).Hydrogen can be replaced by other CO2-type methanogenesis,using formate,carbon monoxide(CO),or alcohols as substrates.The ratio of these two pathways is tightly constrained by the stoichiometry of conversion processes.If the degradation of organic matter is complete(e.g.,degradation of straw in rice paddies),then fermentation eventually results in production of acetate and H2 at a ratio of>67%aceticlastic and<33%hydrogenotrophic methanogensis.However,acetate production can be favored when heterotrophic or chemolithotrophic acetogenesis is enhanced,and H2 production can be favored when syntrophic acetate oxidation is enhanced.This typically occurs at low and elevated temperatures,respectively.Thus,temperature can strongly influence the methanogenic pathway,which may range from 100%aceticlastic methanogenesis at low temperatures to 100%hydrogenotrophic methanogenesis at high temperatures.However,if the degradation of organic matter is not complete(e.g.,degradation of soil organic matter),the stoichiometry of fermentation is not tightly constrained,resulting,for example,in the preferential production of H2,followed by hydrogenotrophic methanogenesis.Preferential production of CH4 by either aceticlastic or hydrogenotrophic methanogenesis can also happen if one of the methanogenic substrates is not consumed by methanogens but is,instead,accumulated,volatilized,or utilized otherwise.Methylotrophic methanogens,which can use methanol as a substrate,are widespread,but it is unlikely that methanol is produced in similar quantities as acetate,CO2,and H2.Methylotrophic methanogenesis is important in saline environments,where compatible solutes are degraded to methyl compounds(trimethyl amine and dimethyl sulfide)and then serve as non-competitive substrates,while acetate and hydrogen are degraded by non-methanogenic processes,e.g.,sulfate reduction.     

重庆:“民生十条”让群众共享改革发展成果

2010年中,重庆市决定,用两年半时间,投入3000亿元,受益群众2000万,可以带动消费4000亿元,拉动GDP增长4至6个百分点,在解决全市群众最关心的十大民生问题上取得重大突破,实现"民生十条"。