沉淀物和生物中U,Th和226Ra的联合测定

用放射化学法对U,Th,~(226)Ra等核素进行联合测定,国外已有不少报道,只是所用的分离方法和所测的介质不同而已。我国学者也做过一些这方面的工作。本工作建立了用三正辛胺-二甲苯萃取分离法对沉积物和生物样中U,Th和~(226)Ra的联合测定方法。 二、主要仪器与试剂     

Enhanced cyanogen chloride formation after UV/PS and UV/H2O2 pre-oxidation and chlorination in natural river water

Ultraviolet/persulfate (UV/PS) and Ultraviolet/hydrogen peroxide (UV/H₂O₂) have attracted much attention in recent years as advanced oxidation processes for water treatment. However, it is not all clear how these two methods affect the formation of cyanogen chloride (CNCl) in the subsequent water chlorination process. In this study, it was found that both UV/H₂O₂ and UV/PS pre-oxidation promoted the formation of CNCl in six actual water samples collected from urban rivers. Glycine, uric acid, arginine and histidine were investigated as the model compounds to explore the effects of different methods on the production of CNCl. The results showed that compared with chlorination alone, pre-oxidation by UV/H₂O₂ and UV/PS can reduce the production of CNCl for glycine and uric acid by up to 95% during post-chlorination process. However, they can greatly promote the formation of CNCl for arginine and histidine by up to 120-fold. In a more detailed investigation, pre-oxidation of histidine formed highly reactive intermediates to chlorine, leading to increased CNCl formation and chlorine consumption. The results showed that the precursors of CNCl was altered after pre-oxidation, and need to be re-evaluated.     

水稻烤田期间N2O排放及其影响因素

水稻田间实验研究了烤田期间的土壤温度、Eh、含水量和裂缝基本性质,矿质态氮以及与氮有关的酶活性的演变规律,及其对N2O排放的影响.试验表明,在水稻分蘖期间烤田,N2O有一个排放高峰,其最高值可达75.6μg·m-2·h-1.在排放高峰后,即使继续烤田,N2O的排放值也将降低.N2O排放与尿素氮肥的施用量没有明显关系.裂缝的生成,改变了N2O的日排放规律.随着烤田时间的延长,脲酶和羟胺还原酶活性呈波动变化,硝酸还原酶活性递减,亚硝酸还原酶活性极低.硝酸还原酶活性与N2O排放之间没有显著相关性.土壤中的脲酶活性与N2O日排放通量呈显著的线性正相关.在烤田期间,NO-3含量呈增加趋势.土壤中的硝态氮含量与N2O排放通量之间呈显著正线性关系.土壤中的铵态氮含量与N2O排放通量之间呈显著负线性相关.     

Geological CO2 Storage as a Climate Change Mitigation Option

Carbon dioxide (CO₂₎ capture and storage is increasingly being considered as an important climate change mitigation option. This paper explores provisions for including geological CO₂ storage in climate policy. The storage capacity of Norway's Continental Shelf is alone sufficient to store a large share of European CO₂ emissions for many decades. If CO₂ is injected into oil reservoirs there is an additional benefit in terms of enhanced oil recovery. However, there are significant technical and economic challenges, including the large investment in infrastructure required, with related economies of scale properties. Thus CO₂ capture, transportation and storage projects are likely to be more economically attractive if developed on a large scale, which could mean involving two or more nations. An additional challenge is the risk of future leakages from storage sites, where the government must take on a major responsibility. In institutional and policy terms, important challenges are the unsettled status of geological CO₂ storage as a policy measure in the Kyoto Protocol, lack of relevant reporting and verification procedures, and lack of decisions on how the option should be linked to the flexibility mechanisms under the Kyoto Protocol. In terms of competitiveness with expected prices for CO₂ permits under Kyoto Protocol trading, the relatively high costs per tonne of CO₂ stored means that geological CO₂ storage is primarily of interest where enhanced oil recovery is possible. These shortcomings and uncertainties mean that companies and governments today only have weak incentives to venture into geological CO₂ storage.     

纳米TiO2光催化反应器研究进展

光催化氧化作为一种高级氧化技术,在环境工程治理领域得到较快的发展。主要介绍了纳米TiO2光催化反应器近年来的研究进展,对各类型反应器的优缺点进行了深入分析,并展望了催化反应器应用前景。     

Ni2+对2-氯酚厌氧降解系统的影响

针对重金属对难降解有毒有机物厌氧降解的影响问题,采用间歇试验法研究Ni2 对2-氯酚(2-CP)厌氧降解系统的影响规律.结果表明,当ρ(Ni2 )＜5 mg/L时,Ni2 对2-CP厌氧降解表现出轻度促进,当ρ(Ni2 )为5～500 mg/L,Ni2 以抑制作用为主,抑制作用随ρ(Ni2 )的增加而增强.Ni2 对原基质及关键中间产物苯酚和苯甲酸的抑制程度表现为:苯酚＞苯甲酸＞2-CP;ρ(Ni2 )低时的驯化能有效提高厌氧污泥对Ni2 毒性的耐受性能,300 mg/L Ni2 对2-CP降解的抑制从驯化前的65%降至驯化后的21%.Ni2 对2-CP厌氧降解的抑制作用与污泥中Ni的截留量之间存在正相关关系.抑制浓度CIP值和方程αC=[1-(I/I*)m]/[1 (I/I*)n)]能较好地表征厌氧生物处理过程受抑制程度.     

环境风险评价中若干问题探讨

社会经济的高速发展,也诱发了新的环境风险可能性的发生,特别是近年来的多种环境风险灾害事故的发生已引起了各国和国际组织的普遍关注。环境风险评价与环境风险管理已成为保护生态环境、维护公众健康的重要内容和制定决策的重要依据。文章结合目前环境风险评价的发展,探讨有关两大类环境风险评价(突发性与非突发性)以及环境风险评价与安全评价的区别,环境风险评价评估标准以及环境风险评价与城市环境管理的一些问题。     

Toxic effects of wastewater from various phases of monosodium glutamate production on seed germination and root elongation of crops

To make a comprehensive assessment on monosodium glutamate (MSG) wastewater pollution, a pollution exposure experiment was carried out on the seed germination and root elongation of wheat, Chinese cabbage and tomato by using the wastewater discharged from different processing phases of MSG production. The results showed that there were significantly positive linear relationships between the inhibitory rates of wheat seed germination and root elongation and the COD_cr of the mother liquor scraps. The toxicity of MSG wastewater to the test crops was in the order of tomato > Chinese cabbage > wheat, indicating that tomato was the most sensitive to the wastewater, and could be considered as an ideal toxic bioindicator. The half-effect concentrations (IC₅₀) based on the seed germination and root elongation of the test crops exposed to the wastewater discharged from various processing phases of MSG production was 22.0–32 432 and 17.3–3320 mg/L, respectively. Translated from Chinese Journal of Applied Ecology, 2006, 17(7): 1286–1290 [译自: 应用生态学报]     

上海市在用车推行I/M制度中检测方法的研究

对在用车实施I/M制度，采用底盘测功机模拟道路工况检测汽车排放污染物，按美国国家环保局（EPA）推荐的方法有3种：瞬态短工总法（IM240）、稳态加速模拟工况法（ASM）和瞬态短工部简易质量分析检测法（VMAS）。根据上海市的试验结果，对上述3种方法的检测精度、设备投资以及运行维护诸方面进行分析比较，阐明上海市采用VMAS方法的依据和应注意的问题，并对应采用的模拟道路工况提出了看法。     

BP网络应用于大气环境监测点的优选

为了对大气环境监测点进行优化选择 ,以大气质量分级标准为训练样本 ,构造BP网络进行训练 ,用训练好的BP网络对某地的大气环境监测采样点进行了优选 ,并与物元分析法优选结果进行比较。结果表明 ,BP网络用于环境测点优选具有较好的客观性和应用性