三峡库区消落带土壤中硫酸盐还原菌对汞甲基化作用的影响

为探究三峡水库这一特殊的周期性干湿交替环境中,硫酸盐还原菌(sulfate-reducing bacteria,SRB)是否在汞的生物甲基化过程中起主导作用,本文以库区消落带原土为研究对象,以灭菌土+接种硫酸盐还原菌Desulfovibrio africanus(D.africanus,DSM-2603)为对照(试验A),在每公斤土壤分别添加0、1、5 mg汞浓度条件下,模拟研究原土(试验B)中总汞(THg)和甲基汞(MeHg)含量的动态变化、总硫酸盐还原菌(SRB)数量变化,以及影响土壤中甲基汞含量的环境因子分析.结果表明,淹水状况有利于THg从土壤中释放,且Hg含量越高,释放越快;菌株D.africanus对汞具生态适应性,其菌数与MeHg含量显著正相关:在5 mg·kg~(-1)Hg条件下,D.africanus菌数可达3.65×10~4cfu·g~(-1),MeHg含量也高达7.60×10~4ng·kg~(-1).值得注意的是,试验B处理中,一方面消落区原土中SRB菌数较少,平均仅193 cfu·g~(-1);另一方面,土壤MeHg含量较低:在5mg·kg~(-1)Hg条件下,MeHg含量仅为5.54×10~3ng·kg~(-1),且总SRB菌数与MeHg含量无显著相关性.由此可以推测,在三峡水库消落区这种非严格厌氧土壤环境中,SRB并非优势菌群,其中还存在着其它对生物汞甲基化起主导作用的好氧或兼性厌氧微生物种群.     

A study on cometabolic bioventing for the in situ remediation of trichloroethylene

Cometabolic bioventing for removal of TCE in the unsaturated zone was studied in a soil column study using methane as growth substrate. A numerical model was developed for simulating the behavior of TCE during cometabolic bioventing. The model parameters were estimated independently through laboratory batch experiments or from the literature. Simulations were found to provide reasonable agreement with the experimental data. The experimental data show that a total TCE remediation efficiency of over 95% was obtained. The volatilization-to-biodegradation ratio of TCE was about 7:1 and T _c values ranging from 0.0078 to 0.07 were obtained in this methane-driven system. Due to the toxicity of the high TCE concentrations to the microbial biomass in the initial stages of the experiment, cometabolic biodegradation was enhanced and was more efficient in the later stages of cometabolic bioventing.     

试谈建立沱江源头水源保护区的必要性

本文根据沱江源头水源涵养林辽度砍代，导致源头蓄水量锐减，以及滥采乱控矿石，造成资源损失与灾害频繁的严峻现实，提出了建立沱江源头水源保护区的必要性。     

江苏省城乡结合部土地资源利用状况与对策

城乡结合部是城市向农村的过渡带。由于其独特的经济地理位置,使这一地带的土地资源呈现出协同效应活跃、恢复原状机会少、抗干扰能力低、边界变化速度快等生态脆弱性特征。由于人们长期不合理的开发活动,导致了结合部内土地资源数量锐减、质量下降、污染严重、投入减少、地面沉降等生态环境变异。迫使我们采取切实有效的措施,解决日趋严重的城乡结合部土地资源危机。     

试论查干湖湿地保护

查干湖国家级自然保护区是我国东北地区重要湖泊群湿地之一,为合理地开发和保护其丰富的自然资源,应在宣传、立法以及严禁开发占地、过度捕捞、水污染等几个方面采取保护措施.     

新疆天山北坡经济带生态环境保护思路探讨

随着区域经济的发展和自然资源的开发，区域生态环境状况面临严峻的考验。本文分析了新疆天山北坡经济带的生态环境现状、特点及发展趋势，重点阐述了该区域生态环境保护与治理的思路，并提出一些相应的对策和建议。     

IMPLEMENTATION OF ACUTE CRITERIA FOR CONSERVATIVE SUBSTANCES1

ABSTRACT: Acute criteria are assigned to the fish and wildlife propagation beneficial use in Oklahoma's water quality standards. Dye studies are analyzed to show that these criteria can be implemented through acute regulatory mixing zones. Acute regulatory mixing zones may be defined as areas in receiving streams where acute numerical criteria may be exceeded without causing acute toxicity. Acute regulatory mixing zones are used to obtain acute waste load allocations. If effluent loading does not exceed acute waste load allocation, acute criteria exceedance is confined to the acute regulatory mixing zone and there is no acute toxicity in the receiving stream. Waste load allocations for acute and chronic criteria are compared to determine which is appropriate to develop permit limits for the dye studies.     

分洪区数字地形模型建立及其应用

从实用的角度介绍了建立分洪区数字地形模型（ＤＴＭ）方程,并给出了在分洪区信息可视化、分洪区特征曲线生成、分洪区二维洪水演进等等方面的应用。     

南黄海6.1级地震的中期预报

归纳介绍了１９９５年两篇报告中的中期预报意见及主要依据，并据此讨论了这次中期预报与南黄海６．１级地震的对应关系及今后长南带海域６级以上地震中期预报的思路     

海平面上升对海岸带环境的影响与危害及其防治对策

本文阐述了过去近百年来和未来特定年份海平面上升的趋势，分析了海平面上升的原因及其对海岸带环境的影响与危害，最后提出了防治对策与措施。