中国突发环境事件时间序列分析

突发性环境事件时间序列特征可表征环境风险管理成效及存在问题。研究表明2000年以来中国突发环境事件预防、控制与管理取得了显著成效,其中,突发性水污染事件、大气污染事件以及噪声振动危害年发生频次呈大幅度降低趋势,但固废污染事件自2003年以来的年发生频次变化不大,而其它突发性环境事件自2002年以来的年发生频次则呈快速增长态势,说明中国在强调突发性水环境和大气环境事件监管的同时,还需加强固废污染事件及其它类型突发环境事件的监控与管理。     

环境监测信息化建设的问题分析与对策建议

环境监测信息化是环境管理现代化的重要手段,信息化建设是监测现代化的重要组成部分。基于当前环境监测信息化建设的现状,分析了建设过程中经常存在的"信息孤岛"、系统失衡、进度延期等问题,提出了建设初期做好IT规划、实施阶段重视项目管理的对策和建议,并依据监测站的实践经验对实施要点加以阐述。解决好这些问题,将推动环境监测信息化建设工作更加高效合理地进行,提升监测信息化程度,对提高环境管理和环境决策的水平具有重要意义。     

Quantification of the inhibitory effect of methyl fluoride on methanogenesis in mesophilic anaerobic granular systems

The inhibitory effect of CH₃F on methanogenesis in mesophilic anaerobic granules was tested at different concentrations (0-10% v/v, in the gas phase) and verified by the stable carbon isotopic signatures of CH₄ and CO₂. The results showed that the inhibitory effect increased with the initial CH₃F concentration up to 5%. The CH₃F concentration causing 50% metabolic inhibition was 0.32%. Complete inhibition of acetoclastic methanogenesis with a 91% reduction in total methanogenic activity was achieved when 5% CH₃F was initially added to the headspace, which resulted in 870 μM dissolved CH₃F in the liquid. It was much higher than that applied in other natural anoxic non-granular systems, indicating that the layered granular structure influenced the inhibitory effect. The obvious increase in hydrogen content indicated that high concentrations of CH₃F (?5%) suppressed hydrogenotrophic methanogenesis as well. The stable inhibition lasted for at least 6 d as the CH₃F concentration decreased slowly with incubation time. These results suggested that CH₃F could be used for investigating methanogenic processes in anaerobic granular systems after the CH₃F concentration and incubation time for specific inhibition of acetoclastic methanogenesis were carefully determined. In the present system, CH₃F concentration of 5% was suggested to be optimal.     

Nano-TiO2 enhances the toxicity of copper in natural water to Daphnia magna

The acute toxicity of engineered nanoparticles (NPs) in aquatic environments at high concentrations has been well-established. This study demonstrates that, at a concentration generally considered to be safe in the environment, nano-TiO₂ remarkably enhanced the toxicity of copper to Daphnia magna by increasing the copper bioaccumulation. Specifically, at 2 mg L⁻¹ nano-TiO₂, the (LC₅₀) of Cu²⁺ concentration observed to kill half the population, decreased from 111 μg L⁻¹ to 42 μg L⁻¹. Correspondingly, the level of metallothionein decreased from 135 μg g⁻¹ wet weight to 99 μg g⁻¹ wet weight at a Cu²⁺ level of 100 μg L⁻¹. The copper was found to be adsorbed onto the nano-TiO₂, and ingested and accumulated in the animals, thereby causing toxic injury. The nano-TiO₂ may compete for free copper ions with sulfhydryl groups, causing the inhibition of the detoxification by metallothioneins.     

A possible new mechanism involved in ferro-cyanide metabolism by plants

Background, aim, and scope  

Ferro-cyanide is one of the commonly found species at cyanide-contaminated soils and groundwater. Unlike botanical metabolism of KCN via the β-cyanoalanine pathway, processes involved in the plant-mediated assimilation of ferro-cyanide are still unclear. The objective of this study was to investigate a possible mechanism involved in uptake and assimilation of ferro-cyanide by plants.     

建筑屋顶雨水径流初期冲刷效应研究

以无量纲化后的雨水径流污染物和径流输送量为基础,通过引入间隙函数,建立了雨水径流污染物的初期冲刷效应定量评价公式,对建筑屋顶雨水初期冲刷现象进行了研究.结果表明:(1)建筑屋顶雨水径流污染物浓度总体上呈现出前期高于后期的现象,且污染物浓度较低,建筑屋顶雨水利用可作为雨水利用的优先方向.(2)间隙函数存在峰值区域,峰值区...     

鲢鳙放养水平对淀山湖浮游植物群落影响的围隔实验

在淀山湖进行放养不同密度鲢、鳙的围隔实验（密度水平梯度设置为0、40、80和120 g/m3）,探索鲢、鳙的现场控藻效果。结果表明,实验后期（8—9月）,鲢、鳙放养密度为80 g/m3和120 g/m3的围隔对叶绿素a的去除效果显著（P〈0.05）;且放养密度为80 g/m3的围隔蓝藻比例降幅最明显。鲢、鳙对较大个体藻...     

阴极氧还原产电生物可渗透反应栅的研究Ⅱ.酸蚀处理对不锈钢丝电极性能的影响

不锈钢毛虽然用作阴极氧还原产电生物反应栅（CORE—PRB）的电极材料虽然有很多优点,但是反应电流较小。尝试对不锈钢毛进行酸蚀处理后用作电极材料,并分别研究比较了4种不同电极组合的产电反应性能。酸蚀处理显著提高不锈钢毛阳极的反应性能,并对提高不锈钢毛阴极的反应性能有一定作用。酸蚀的作用主要是使不锈钢毛表面变得粗糙,有利于提高电极表面积和材料的生物亲和性。虽然生物产电反应对COD降解的直接贡献不到10％,但是不同电极组合下COD的去除率与它们生物产电反应的贡献率呈现高度正相关性。     

饮用水源水无机金属污染的应急处理

根据密云水库供水现状,针对突发性无机金属污染事件,采用聚合氯化铝辅助化学沉淀法进行应急处理。选用Cu2＋、Fe2＋、Zn2＋和Cd2＋ 4种金属离子为目标污染物,首先通过小试实验确立了最佳混凝处理条件。结果表明,调节pH值为8．0左右,可使初始浓度为5mg／L和10mg／L的Cu2＋浓度降至0．96mg／L和0．67mg／L;初始浓度为1．5mg／L和3mg／L的Fe2＋浓度降至0．27mg／L和0．24mg／L;初始浓度为0．05mg／L和0．1mg／L的Cd2＋浓度降为0．0089mg／L和0．0078mg／L;调节pH值为9．0时,可使初始浓度为5mg／L和10mg／L的Zn2＋浓度降至0．57mg／L和0．48mg／L。4种污染物出水浓度均低于国家饮用水标准。在小试基础上,在北京第九水厂开展无机金属污染处理的中试实验,结果表明所选用的聚合氯化铝辅助化学沉淀法简便易行,可实现污染物快速、有效去除。     

超重力旋转填料床中柠檬酸钠法烟气脱硫

采用柠檬酸-柠檬酸钠缓冲溶液作为吸收液,在超重力旋转填料床(简称填料床)中进行模拟烟气中SO2的吸收和解吸实验,考察了吸收液组成及各操作参数对SO2吸收率及解吸率的影响.实验结果表明:吸收过程中吸收液的柠檬酸浓度越高、吸收液初始pH 越高,SO2吸收率越高;填料床转速增大、液气比增大,SO2 吸收率下降速率增大;解吸过...