Sorption of 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT) by clays and organoclays

This study focused on the sorption isotherms of 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (p,p'-DDT) and 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (p,p'-DDE) on different original clays (i.e., zeolite, montmorillonite and attapulgite) and organoclay complexes. Sorption of organic pollutants was determined using gas chromatographic (GC) techniques to investigate the sorption behavior, and characterize the effect of, different organic cations. The original clays only sorbed low amounts of p,p'-DDT and p,p'-DDE, and the sorptive curves can be classified as L-shaped. Organoclays exhibited higher amounts of p,p'-DDT and p,p'-DDE sorption. The p,p'-DDT and p,p'-DDE sorption increased with increasing total organic carbon (OC) content of the organoclays. For hexadecyltrimethylammonium (HDTMA)-modified organoclays, the dominant adsorptive medium showed the partitioning sorption of hydrophobic-hydrophobic interaction, indicating no competitive sorption. The sorptive curves can be classified as C-shaped of constant partition (CP). However, benzyltrimethylammonium (BTMA)-modified organoclays exhibited competitive sorption. The sorption isotherm curves can be classified as S-shaped. The sorptive capacity of the HDTMA-modified organoclays for p,p'-DDT were higher than those for p,p'-DDE, but the BTMA-modified organoclays showed a reverse trend. This can be attributed to the different structures and shapes of organic cations, giving different sorptive mechanisms. The p,p'-DDT and p,p'-DDE sorption onto HDTMA-modified organoclays were caused by chemical interaction, with the BTMA modified organoclays occuring due to physical sorption.     

应急监测中样本有无放射性的讨论

利用统计学方法提出了如何在应急监测中判断样本有无放射性,并结合实际监测做出了具体应用。     

基于灰色-随机风险率方法的湖泊水质分析

湖泊水环境是一个受多种不确定性因素限制的复杂系统。以内蒙古乌梁素海为研究对象,应用水质超标灰色-随机风险率的计算方法和系统可靠性分析理论建立了单项参数评价模型和综合参数评价模型,分析湖泊入口断面水质存在的潜在风险性。结果表明:乌梁素海镉的Ⅴ类达标率仅为7.69%~23.89%,镉污染已经十分严重,硫化物和氰化物的Ⅲ类和Ⅴ类达标率都达到100%,所以几乎不受这两项指标的污染。该方法能较好地反映乌梁素海入口断面不同水质参数的污染强度和污染历时的变异过程,为湖泊水环境风险的决策和管理工作提供了参考依据。     

蜥蜴生态毒理学研究进展

蜥蜴是爬行动物的重要组成部分,开展蜥蜴的生态毒理学研究对爬行动物毒理学研究具有一定代表性。本文介绍了蜥蜴生态毒理学研究的重要性,系统回顾了前人对重金属以及有机污染物所开展的相关研究,以及近年来在模式动物筛选方法和标准试验方法的建立上取得的成就,并对未来的工作进行了展望。     

Enhancement of activated sludge performance on ammonium removal by clinoptilolite

This study evaluated the influence of clinoptilolite on the performance of activated sludge system shocked by high concentration of ammonium. The ammonium and chemical oxygen demand (COD) removal from the experimental reactor containing clinoptilolite and from the clinoptilolite-free control reactor was determined. The ammonium and COD removal was approximately 8 and 20% higher in the experimental reactor than in the control reactor, respectively. The removal increased with an increase in clinoptilolite concentration over the tested range up to 50?mg?L^?1. The presence of clinoptilolite resulted in the sludge flocs being more compacted with smoother surfaces and edges. Molecular biological analysis revealed that clinoptilolite increased the DNA diversity, richness, and evenness of sludge microbes. The enhanced-performance activated sludge previously treated with clinoptilolite was less influenced by the shock of ammonium than non-treated sludge in terms of the ammonium and COD removal. These results suggest that clinoptilolite enhanced the performance of activated sludge system in the removal of ammonium and COD. Amendment of activated sludge with natural zeolites may thus improve the efficiency of wastewater treatment.     

基于稳定同位素的天津市北塘排污河污染源解析研究

依据不同采样点污染物组分不同,分析各样品中氢、氧同位素组成比率,判断各采样点污染贡献率。研究以天津市北塘排污河为例,将其分为若干段,每一段作为一个箱式模型对流人和流出区段的溶解态氢、氧同位素比率进行检测,借助氢、氧同位素成分比率图求算各区段的污染贡献率,同时判断是否有新污染源增加,研究表明北塘排污河下游中心桥闸处污染贡献率最高,达到污染总量的70％,另外发现2个污染未知源,分别位于北塘排污河中游检测点和山岭子问、山岭子与永和闸间。     

城镇防灾避难场所规划研究

城镇防灾避难场所是城镇灾后应急避难、救援、恢复重建的重要组成部分,也是城镇平时功能的主要构成部分。首先按照应对灾害的主要类型,将避难场所分为气象型避难场所和地质型避难场所,相对应的为建筑型避难场所与场地型避难场所。继而与城市规划中的用地性质相关联,从防灾避难的角度将城镇用地划分为"靶区""防灾避难据点"与"防灾避难通道"。总结城镇防灾避难空间结构的组成要素、组构原则与组成方式,并以三种模式进行模型化构建。进而概括了城镇防灾避难场所的规划要点、规划内容与技术路线,并以深圳防灾避难场所规划加以佐证。得出了结论:防灾避难场所是城镇整体空间不可分割的一部分;城镇防灾避难空间规划应从城镇整体空间结构出发,合理规划防灾避难场所与防灾避难通道,优化用地功能与规模,提升城镇整体的防灾避难能力。     

无机离子SO42-对小麦幼苗积累稀土的影响

采用ＭＩＮＴＥＱＡ 程序计算出在无机离子SO₄^2-存在下,轻（Ｌａ）、中（Ｇｄ）、重（Ｙ）３ 种稀土元素在溶液中的形态分布．研究了在水培条件下ＳＯSO₄^2-对３种稀土元素在小麦幼苗根、茎和叶部的积累规律．热力学实验表明,小麦幼苗在加SO₄^2-的稀土元素溶液中培养３０ｄ 后,小麦根部对Ｌａ、Ｇｄ 的积累受抑制,而对Ｙ的积累却明显提高;加入SO₄^2-后茎叶部对Ｌａ、Ｙ积累值改变不明显,但对Ｇｄ的积累有所增加．生长动态实验表明,在SO₄^2-存在下,小麦幼苗根部对稀土的积累随时间增加而增加,其积累值符合线性递增函数方程,相关系数ｒ＞ ０．９４;而茎叶部最初积累能力较强,SO₄^2-的加入对小麦植株动态吸收稀土规律无明显影响．     

憎水性污染物在表面活性剂溶液中的增溶动力学

为了解表面活性剂溶液对憎水性污染物增溶过程的影响因素,研究六氯乙烷在Ｔｗｅｅｎ２０溶液中的增溶动力学过程,建立了六氯乙烷在表面活性剂溶液中增溶的传质模型．模型表明当六氯乙烷总表面积固定时,其溶解速率同六氯乙烷在表面活性剂溶液中的表观溶解度和表观传质系数呈正相关．发现六氯乙烷在表面活性剂溶液中的表观传质系数和纯水中的相比降低了,但由于表面活性剂对六氯乙烷的增溶作用导致其溶解速率总体上是提高的     

络合萃取法与生物法处理含酚废水技术经济比较

从技术经济角度对络合萃取法与生物法处理含酚废水进行了比较。建立了投资及净现值与处理量和浓度的关系式。结果表明：当浓度小于265mg/L时,络合萃取法与生物法随处理量的不同在投资上存在差别;当浓度大于265mg/L时,无论处理量为多少,络合萃取法的投资始终小于生物法的投资。对于处理量较大、浓度较高的废水,采用络合萃取法能获得较大的净现值（NPV）;当回收酚时,盈亏平衡点的浓度为1000mg/L,高于此浓度,络合萃取法处理为盈利项目。