生态土壤渗滤系统启动周期研究

利用室内模拟试验装置,考察了4种生态土壤渗滤系统在0.1 m3/(m2·d)的水力负荷条件下对生活污水中TP、COD和NH3-N的去除效果及启动周期; 同时对整个系统及同类生态工艺启动周期的判断方法做了探讨.研究结果表明,生态土壤渗滤系统对TP、COD和NH3-N的启动周期分别为15～27 d、24～40 d和24～26 d; 土壤渗滤系统对TP的启动周期最短,对COD的启动周期最长; 处理系统启动周期的判断原则是综合考察系统对主要污染物各自的启动周期,以最长的作为系统启动周期.4组试验中,1#和2#系统的启动周期为40 d; 3#和4#的为24 d.     

煤炭地下气化灰渣浸泡实验及Zn、Cd、Pb、As环境效应分析

为研究煤炭地下气化灰渣的环境效应,主要是对地下水的影响,以洛阳半焦煤为研究对象,进行煤炭地下气化的模型实验.取气化后的灰渣浸泡,测定浸出液中Zn、Cd、Pb和As4种元素的质量浓度.浸出液中Zn、Cd和As的质量浓度均低于地下水Ⅲ级标准.在饮用水允许的浓度范围内,不会对地下水造成多大污染;Pb的质量浓度在地下水Ⅴ类标准内,可能会对地下水造成一定污染.现场应考虑采取适当处理措施.4种元素的质量浓度均远低于浸出毒性鉴别标准值,因而不属于具有浸出毒性的危险废物.研究表明洛阳半焦煤地下气化灰渣中的Zn、Cd、Pb和As对环境的影响较小,不会对地下水产生多大影响.但在现场的工业试验中,由于长期的积累作用,也可能使元素的累积浓度超过地下水允许浓度,应定期监测.     

Global fallout Pu recorded in lacustrine sediments in Lake Hongfeng, SW China

Studies on the distribution and isotope compositions of fallout Pu are important for source characterization of possible future non-fallout Pu contamination in aquatic environments, and useful for dating of recent sediments to understand the pollution history of environmental contaminants. We present the historical record of atmospheric Pu fallout reconstructed from a sediment core from Lake Hongfeng, China. The Pu activity profile was in agreement with the 137Cs profile. Inventories were 50.7 Bq m(-2) for 239+240Pu and 1586 Bq m(-2) for 137Cs. The average 240Pu/239Pu atom ratio was 0.185+/-0.009, indicating that Pu originated from global stratospheric fallout rather than from direct tropospheric or close-in fallout from the Chinese nuclear testing conducted in the 1970s. Our data suggested that Lake Hongfeng would be an ideal setting for monitoring atmospheric fallout and environmental changes in this region.     

Inverse modeling of multicomponent reactive transport through single and dual porosity media

Compacted bentonite is foreseen as buffer material for high-level radioactive waste in deep geological repositories because it provides hydraulic isolation, chemical stability, and radionuclide sorption. A wide range of laboratory tests were performed within the framework of FEBEX (Full-scale Engineered Barrier EXperiment) project to characterize buffer properties and develop numerical models for FEBEX bentonite. Here we present inverse single and dual-continuum multicomponent reactive transport models of a long-term permeation test performed on a 2.5 cm long sample of FEBEX bentonite. Initial saline bentonite porewater was flushed with 5.5 pore volumes of fresh granitic water. Water flux and chemical composition of effluent waters were monitored during almost 4 years. The model accounts for solute advection and diffusion and geochemical reactions such as aqueous complexation, acid-base, cation exchange, protonation/deprotonation by surface complexation and dissolution/precipitation of calcite, chalcedony and gypsum. All of these processes are assumed at local equilibrium. Similar to previous studies of bentonite porewater chemistry on batch systems which attest the relevance of protonation/deprotonation on buffering pH, our results confirm that protonation/deprotonation is a key process in maintaining a stable pH under dynamic transport conditions. Breakthrough curves of reactive species are more sensitive to initial porewater concentration than to effective diffusion coefficient. Optimum estimates of initial porewater chemistry of saturated compacted FEBEX bentonite are obtained by solving the inverse problem of multicomponent reactive transport. While the single-continuum model reproduces the trends of measured data for most chemical species, it fails to match properly the long tails of most breakthrough curves. Such limitation is overcome by resorting to a dual-continuum reactive transport model.     

城市灾害相对承载力分析与模型的建立

如何评价城市系统综合承灾能力,这一直足被普遍关注也是较难解决的问题.在综合型可持续发展度评价模型的基础上建立的城市系统灾害相对承载力评价模型,为解决上述问题提供了新的思路.通过对城市复杂功能系统中社会子系统、经济子系统和环境子系统的划分及其相互影响分析,找出各子系统中对承灾能力的重要影响因素,进行加权整合后分别得出社会安全指数、经济"软"指数、环境指数和基础设施指数,应用这些承灾能力指数建立了灾害相对承载力模型.建模计算过程中发现因素量化方式的选取和权重的确定是比较重要的,会影响灾害相对承载力的合理取值,因此以经济"软"指数为例,提出了用协调度系数乘积代替原计算式值以使其取值范围在合理区间内的解决方式.     

高氯低COD值水样的无汞快速测定法

以硝酸银和硫酸铬钾代替硫酸汞来消除 COD 测定中的氯离子干扰,同时将重铬酸钾溶液的浓度降低为0.100 mol／L,并用硫磷混酸代替硫酸,该方法经过对标准样品和实际样品的测定,表现出对于测定氯离子含量低于25000 mg／L的高氯低 COD 值水样具有较好的准确度和精密度,同时可以实现银盐的回收再利用。     

土壤中酞酸酯类化合物监测方法的质量控制研究

从监测结果控制的角度对近10年的土壤中PAEs监测方法进行了探讨,重点比较了索氏萃取柱净化GC/MS、微波萃取柱净化GC、加速溶剂萃取柱净化GC/MS和加速溶剂萃取GPCGC/MS方法的检出限、精密度和准确度。旨在为中国土壤监测方法的建立提供基础支撑,为开展质量控制工作提供评价依据。     

环境监测实验室方法确认过程中常见问题探讨

根据实验室资质认定对于方法确认的要求,结合环境监测实验室的特点,提出了新项目方法确认的具体步骤,并分析了其中存在的常见问题。指出在方法确认过程中,应严格按照标准方法和监测技术规范进行全过程试验,尤其不能忽视采样现场实验、空白实验和检出限的测定。建议在精密度与准确度检验过程中,使用高、中、低不同浓度的有证标准样品,实际样品加标回收,比对试验（方法比对、人员比对、实验室间比对）,增加分析次数等多种手段,确保新项目开展的可靠性。     

A mini review of fluoride-induced apoptotic pathways

Fluorine or fluoride can have toxic effects on bone tissue and soft tissue at high concentrations. These negative effects include but not limited to cytotoxicity, immunotoxicity, blood toxicity, and oxidative damage. Apoptosis plays an important role in fluoride-induced toxicity of kidney, liver, spleen, thymus, bursa of Fabricius, cecal tonsil, and cultured cells. Here, apoptosis activated by high level of fluoride has been systematically reviewed, focusing on three pathways: mitochondrion-mediated, endoplasmic reticulum (ER) stress-mediated, and death receptor-mediated pathways. However, very limited reports are focused on the death receptor-mediated apoptosis pathways in the fluoride-induced apoptosis. Therefore, understanding and discovery of more pathways and molecular mechanisms of fluoride-induced apoptosis may contribute to designing measures for preventing fluoride toxicity.     

Robust Regression with Data-Dependent Regularization Parameters and Autoregressive Temporal Correlations

We introduce robust procedures for analyzing water quality data collected over time. One challenging task in analyzing such data is how to achieve robustness in presence of outliers while maintaining high estimation efficiency so that we can draw valid conclusions and provide useful advices in water management. The robust approach requires specification of a loss function such as the Huber, Tukey’s bisquare and the exponential loss function, and an associated tuning parameter determining the extent of robustness needed. High robustness is at the cost of efficiency loss in parameter loss. To this end, we propose a data-driven method which leads to more efficient parameter estimation. This data-dependent approach allows us to choose a regularization (tuning) parameter that depends on the proportion of “outliers” in the data so that estimation efficiency is maximized. We illustrate the proposed methods using a study on ammonium nitrogen concentrations from two sites in the Huaihe River in China, where the interest is in quantifying the trend in the most recent years while accounting for possible temporal correlations and “irregular” observations in earlier years.