Evaluation of mixture effects in a crude extract of compost using the CALUX bioassay and HPLC fractionation

Potential synergistic interactions between polycyclic aromatic hydrocarbons in a household sewage sludge compost extract were investigated using the Dioxin-Responsive Chemical-Activated Luciferase gene eXpression (DR-CALUX) assay and reverse-phase high-performance liquid chromatography (RP-HPLC) fractionation. The biological activity of the crude extract was measured in vitro using the CALUX assay. The CALUX activity of the extract was as potent as 360-pg CALUX-TEQ (2,3,7,8-TCDD equivalent value) per g sample, this was 70 times above the WHO-TEQ value which was derived from chemical analyses of dioxins/furans and dioxin-like PCBs of the mixture. The CALUX activity pattern of the crude extract and the retention times of 26 polycyclic aromatic compounds (PACs), as determined by RP-HPLC on an octadecylsilica column, suggested that the dioxin-like compounds with the log K(OW) (n-octanol/water partition coefficient) values corresponding to 6.0-7.0 contributed highly to the whole activity. The CALUX activity of the crude extract was three times the sum of the CALUX activities of the RP-HPLC separated fractions. Mixture effects were assessed by co-exposure of each HPLC fraction and 2,3,7,8-TCDD to the cells. The four concentration levels of added 2,3,7,8-TCDD corresponded to the TEQ value in the original compost sample. The experimental CALUX activity was higher than the predicted CALUX activity for some fractions. It was demonstrated that some compounds in the compost sample interacted synergistically with 2,3,7,8-TCDD in terms of dioxin-like activity. This finding points out the necessity for detailed investigation of synergistic effects in environmental samples.     

600 m3湿式氢气贮柜燃烧爆炸伤害效应预测

建立了某动力公司600m^3易燃易爆湿式氢气贮柜燃烧爆炸事故的6种模型,给出边界条件和计算过程,提出爆炸事故伤害效应预测指标。进行燃烧爆炸事故伤害效应预测,为氢气贮柜发生燃烧爆炸事故危害性评估提供了理论依据。     

燕化公司固体废物堆埋场对地下水的影响分析

对北京燕山石化公司固废堆埋场进行了回顾性评述。分析了堆埋场易发生渗漏的可能途径和石化行业固废淋滤液中主要污染物的特性,分别模拟测定和估算了地基和坝基的渗漏量。现场取样分析认为废渣液及淋滤污水目前对该地区地下水影响较小,工程在运行10a后仍然具有较好的防渗功能。      

磁场协同交变脉冲电化学场处理垃圾渗滤液

以自行研制的交变脉冲电源为基础,在自制的磁场-电化学场一体化水处理反应器中,使用铝片为可溶性电极,并同时施加磁场和交变脉冲电解电流,对垃圾渗滤液进行处理.在磁感应强度为0.08 T,脉冲峰值电流密度为5 A/dm2,平均脉冲峰值电压为2.0 V,脉冲电流周期为3 s及处理时间为90 min的工艺条件下,相对于相同电化学条件的单一交变脉冲电絮凝处理,新鲜垃圾渗滤液的COD_Cr与NH₃-N的去除率分别提高了8.41%和6.56%;老龄垃圾渗滤液的COD_Cr与NH₃-N的去除率分别提高了16.01%和7.82%.表明磁场与电化学场的协同作用明显地提高了废水的处理效果.      

应用DAT-IAT工艺污水处理厂的运行效果分析

天津经济技术开发区污水处理厂采用先进的DATIAT工艺,针对该污水处理厂冬季和夏季的实际运行效果分别进行研究、比较,并就DAT池和IAT池对有机物的去除效果进行分析。研究发现,污水处理厂实际运行中,对BOD5的去除效果十分彻底,对CODCr的去除效果一般,但都能够保证出水达标。DATIAT工艺系统的抗冲击负荷能力较强污水处理厂DAT池过高的BOD5去除率对后续的脱氮除磷效果会产生不利的影响。     

邻苯二甲酸二丁酯在不同品种菜心-土壤系统的累积

在邻苯二甲酸二丁酯(DBP)污染的水稻土中盆栽不同品种菜心,采用GC/MS研究了菜心-土壤系统中DBP的分布特征.结果表明,不同品种菜心茎叶和根系对DBP的吸收累积存在明显差异;不同品种菜心茎叶中DBP含量与其叶面积大小之间存在一定的正相关关系.不同品种菜心-土壤系统中DBP的分布特征明显不同,新选45天油菜心表现为茎叶和根系中DBP含量较低,盆栽后土壤中DBP含量也较低;特青60天菜心和新选油青四九菜心表现为茎叶和根系中DBP含量较低,但盆栽后土壤中DBP含量较高;油青60天菜心表现为茎叶和根系中DBP含量较高,盆栽后土壤中DBP含量也较高.     

水资源短缺对北京农业的不利影响分析与对策

北京市农业水资源短缺状况十分严峻。针对水资源短缺对北京农业经济、农村生态环境和社会稳定产生的影响,进行了全面、深入的分析,认为北京市目前的用水政策会进一步加剧农业用水的紧张趋势。进而提出了诸如发展利用和推广节水农业技术、大力建设节水灌溉工程设施、调整种植结构、发展特色农业、适度发展污水灌溉、建设地下水应急备用水源、加速推广雨洪利用技术、实施人工增雨工程、加强农村水资源的宏观和微观管理等相应的对策和建议。     

The role of migration and founder effect for the evolution of cooperation in a multilevel selection context

The idea that natural selection can be meaningfully applied at the group level may be more important than previously thought. This perspective, a modern version of group selection, is called multilevel selection. Multilevel selection theory could incorporate previous explanations for the evolution of cooperation including kin selection. There is general agreement that natural selection favors noncooperators over cooperators in the case of an unstructured population. Therefore, the evolution of cooperation by multilevel selection often requires positive assortment between cooperators and noncooperators. The question is how this positive assortment can arise in the ecological meaning. We constructed an individual-based model of multilevel selection and introduced migration and evolution. The results showed that positive assortment was generated especially when a migration strategy was adopted in which individuals respond specifically to bad environmental conditions. It was also shown that the founder effect in the evolutionary process could further facilitate positive assortment by working with migration. We analyzed assortment by using relatedness defined in group-structured populations. The fact that cooperation was achieved by such migration and by the founder effect highlights the importance of sensitiveness to the ecological environment and of fluctuations in group size, respectively.     

丙烯酰胺生态毒理行为研究进展

丙烯酰胺(AM)是一种重要的化工产品,在不同领域均有广泛的应用,其生态毒理行为一直是人们关注的焦点.论文从AM的理化特性出发,概述了AM在生物体内的行为,探讨了AM对生物体的危害,分析了AM在环境中的归宿,提出了AM的预防措施,为今后AM的使用、治理及预防提供了一定的参考和依据.     

利用涡流空化效应降解水中罗丹明B

涡流空化通过特殊结构的涡流仓产生,流体在涡流仓中形成压力远低于大气压力的低压区域,从而产生空化效应.通过CFX计算软件对涡流形成情况进行了模拟计算,确定了适宜的结构参数.对罗丹明B进行了实际降解试验,考察了压力和温度对降解的影响,结果表明,压力提高对降解有利,而温度的影响有一定复杂性.涡流空化降解和超声空化降解的对比试验结果表明,涡流空化降解效率远大于超声空化.