水质二硝基甲苯环境标准样品的研制

报道了水和废水环境监测所用水质二硝基甲苯环境标准样品的研制情况。其中对水质二硝基甲苯环境标准样品的作用、样品的制备、均匀性测定、稳定性考察以及定值分析等方面做了较详细的介绍。     

高分解度泥炭土-土水特征曲线研究∗

为了明确非饱和泥炭土的土水特征及其影响因素,以原状泥炭土和人工调配的 5 种不同有机质含量的重塑泥炭土为研究对象,采用滤纸法测试其基质吸力,绘制出相应的土水特征曲线,分析泥炭土原状样和重塑样土水特性的差别,以及不同有机质含量对于泥炭土土水特性的影响;选用 Gardner 模型、Van Genuchten 模型和 Fredlund & Xing 模型对试验结果进行拟合,比较 3 种模型对泥炭土的适用性;最后分析比较高分解度泥炭土的土水特征曲线与其他土类的差异。试验结果表明：有机质含量相同时,原状土样的进气值和残余值小于重塑土样的进气值和残余值,说明原状土样的持水能力弱于重塑土样;有机质含量对泥炭土的土水特征曲线有很大影响,随着土中有机质含量的增加,土的持水能力变强,土样的进气值从 155 kPa 增长到 1 486 kPa,残余值从 4 796.7 kPa 增长到 35 101.5 kPa;3 种模型拟合优良度依次为 Van Genuchten 模型、Fredlund & Xing 模型、Gardner 模型;通过对比,发现高分解度泥炭土持水能力最强,其特征值大于膨润土。     

利用场地表征参数研究岷漳地区地震动相对变化趋势

近地表场地条件所引起的地震动差别可以造成不同场地上建筑物震害的显著差异。为了在岷漳地区的震害预测和长期发展规划中考虑场地条件差异性,提出联合V_(s30)和地形标度曲率作为场地表征参数来获得研究区地震动相对变化趋势图的方法。研究表明:土质山体土质河谷基岩山体基岩河谷是研究区地震动变化的基本规律,但因覆盖层厚度和地形条件的不同,具体场地的地震动变化也有不同。总体上,地震动峰值加速度的放大程度主要与近地表V_(s30)相关,V_(s30)越大地震动峰值加速度的放大越小,地震频谱受频率标度地形曲率和覆盖层厚度共同影响,分别在相应的特征频率处放大。该研究可为区域地震动预测提供理论依据,为制定区域长期发展规划和建筑抗震设计提供重要的基础资料,基于场地表征参数研究区域地震动相对变化趋势的方法也可应用于地震烈度速报和地震灾害快速评估等领域。     

基于筛选层面的北京地区典型二噁英类的生态风险评价

以二 类为研究对象,利用风险评估识别排序模型在稳态假设下对北京地区环境中二 类的潜在生态风险进行模拟计算和评估,并根据计算结果对污染物按风险进行归类.模拟结果表明:当二 以估算的实际排放比例和排放量进入到大气、水和土壤介质中时,以环境介质中的阈值进行分析时,2,3,7,8-四氯二苯并-对-二 (2,3,7,8-TCDD)的风险评价因子(RAF)值为235,归为A类化合物,八氯二苯并-对-二 (OCDD)的RAF值为0.246,归为C类化合物.以生物介质中的阈值进行评价时,2,3,7,8-TCDD和OCDD的RAF值分别为6.70×10-3和1.11×10-3,均归为D类化合物.其余二 类同族体化合物的生态风险介于这二者之间.     

Groundwater arsenic removal by coagulation using ferric(III) sulfate and polyferric sulfate: A comparative and mechanistic study

Elevated arsenic (As) in groundwater poses a great threat to human health. Coagulation using mono-and poly-Fe salts is becoming one of the most cost-effective processes for groundwater As removal. However, a limitation comes from insufficient understanding of the As removal mechanism from groundwater matrices in the coagulation process, which is critical for groundwater treatment and residual solid disposal. Here, we overcame this hurdle by utilizing microscopic techniques to explore molecular As surface complexes on the freshly formed Fe flocs and compared ferric(III) sulfate (FS) and polyferric sulfate (PFS) performance, and finally provided a practical solution in As-geogenic areas. FS and PFS exhibited a similar As removal efficiency in coagulation and coagulation/filtration in a two-bucket system using 5 mg/L Ca(ClO)₂. By using the two-bucket system combining coagulation and sand filtration, 500 L of As-safe water (<10 μg/L) was achieved during five treatment cycles by washing the sand layer after each cycle. Fe k-edge X-ray absorption near-edge structure (XANES) and As k-edge extended X-ray absorption fine structure (EXAFS) analysis of the solid residue indicated that As formed a bidentate binuclear complex on ferrihydrite, with no observation of scorodite or poorly-crystalline ferric arsenate. Such a stable surface complex is beneficial for As immobilization in the solid residue, as confirmed by the achievement of much lower leachate As (0.9 μg/L-0.487 mg/L) than the US EPA regulatory limit (5 mg/L). Finally, PFS is superior to FS because of its lower dose, much lower solid residue, and lower cost for As-safe drinking water.     

石家庄市春季景观水体nirS型反硝化细菌群落特征分析

选取石家庄市主城区4个典型景观水体作为研究对象,在对水体水质特征分析的基础上,运用Illumina高通量测序技术对景观水体中的nir S型反硝化细菌种群结构和多样性进行测定,探究春季景观水体水质与nir S型反硝化细菌群落的相互关系.结果表明,4个景观水体中氮素含量为4. 43～13. 83 mg·L-1,氮素污染较严重;基于三维荧光光谱的特征指数分析,4个景观水体均呈现出较强的自生源及弱腐殖质特征; Illumina高通量测序结果表明,不同景观水体中nir S型反硝化细菌大多为变形菌门,在优势菌属上差异显著; unclassified_Bacteria(53. 52%)、假单胞菌(Pseudomonas)(60. 48%)和红杆菌属(Rhodobacter)(46. 94%)分别为裕西、水上和长安公园水体中的优势菌属,unclassified_Bacteria(36. 19%)和unclassified_Proteobacteria(23. 44%)为世纪公园水体中的优势菌属;冗余分析(RDA)结果表明,裕西公园反硝化细菌主要受硝氮、总氮和溶解氧的影响,水上公园反硝化细菌受总磷的影响较大,长安公园反硝化细菌主要受氨氮和亚硝氮的影响,世纪公园反硝化受总磷、亚硝氮和氨氮的影响较大.综上表明,春季不同景观水体的水质以及nir S型反硝化细菌的群落结构差异显著,通过开展景观水体水质、反硝化群落以及影响因素的研究,有助于对城市水系的水质特征以及反硝化群落结构的认识,对基于该水质特征的高效反硝化菌剂的研发具有指导意义.     

好/厌氧条件下反硝化细菌脱氮特性与功能基因

从西安市金盆水库沉积物中分离筛选出1株高效反硝化细菌,经形态学观察和16S r DNA测序鉴定为施氏假单胞菌(Pseudomonas stutzeri),命名为KK99.探究了该菌株在好/厌氧条件下的脱氮特性以及nar G、nir S和nos Z功能基因的表达水平.结果表明,KK99菌株在好/厌氧条件下,均能进行反硝化作用,且在两种不同的条件下均具有高效的脱氮效率.经过24h的培养,其总氮(TN)去除率分别为85.08%和89.05%.胞内功能基因nos Z和nir S的表达量较高,nos Z在好氧条件下的反硝化发挥主要作用,nir S在厌氧条件下的反硝化发挥主要作用,nar G在两种条件下的表达均较低.同时该菌株还具有同步硝化反硝化性能,在好氧条件下,能同时去除硝酸盐氮和氨氮,24 h时,TN去除率为76%.施氏假单胞菌(P.stutzeri KK99)将为微污染水体富营养化控制和总氮削减工程应用提供菌源保障.     

中药废水主要成分厌氧生物降解途径研究

通过小试研究,利用气-质联机（GC-MS）对黄芩甙的厌氧生物降解曲线和途径进行了探讨,对黄芩甙的降解数据进行趋势化模拟和线性回归分析,得到了相应的降解动力学方程.黄芩甙可能的降解途径为“脱糖→脱苯→开环→饱和化→拆链”,降解时间需47 h以上, 厌氧分解的主要产物是小分子氧化物,如醇、醛、酸、酯、烯烃以及还原态饱和烷烃.结果表明,黄芩甙降解的限速步骤在水解酸化阶段,适宜采用两相厌氧消化技术和较长的停留时间进行处理.     

Groundwater arsenic removal by coagulation using ferric(Ⅲ)sulfate and polyferric sulfate: A comparative and mechanistic study

Elevated arsenic(As) in groundwater poses a great threat to human health. Coagulation using mono- and poly-Fe salts is becoming one of the most cost-effective processes for groundwater As removal. However, a limitation comes from insufficient understanding of the As removal mechanism from groundwater matrices in the coagulation process, which is critical for groundwater treatment and residual solid disposal. Here, we overcame this hurdle by utilizing microscopic techniques to explore molecular As surface complexes on the freshly formed Fe flocs and compared ferric(III) sulfate(FS) and polyferric sulfate(PFS)performance, and finally provided a practical solution in As-geogenic areas. FS and PFS exhibited a similar As removal efficiency in coagulation and coagulation/filtration in a two-bucket system using 5 mg/L Ca(ClO)_2. By using the two-bucket system combining coagulation and sand filtration, 500 L of As-safe water( 10 μg/L) was achieved during five treatment cycles by washing the sand layer after each cycle. Fe k-edge X-ray absorption near-edge structure(XANES) and As k-edge extended X-ray absorption fine structure(EXAFS) analysis of the solid residue indicated that As formed a bidentate binuclear complex on ferrihydrite, with no observation of scorodite or poorly-crystalline ferric arsenate. Such a stable surface complex is beneficial for As immobilization in the solid residue, as confirmed by the achievement of much lower leachate As(0.9 μg/L–0.487 mg/L)than the US EPA regulatory limit(5 mg/L). Finally, PFS is superior to FS because of its lower dose, much lower solid residue, and lower cost for As-safe drinking water.     

松花湖沉积物溶解性有机质荧光光谱特性

溶解性有机质(DOM)对于湖泊的主要污染指标(如COD等)有着较大的影响,而沉积物亦是湖泊污染的主要来源,因此沉积物DOM荧光光谱特性的研究对进一步揭示湖泊污染本质有重要意义.采集了松花湖20个点位的沉积物,利用激发发射矩阵光谱-平行因子分析(EEM-PARAFAC)技术对沉积物中的DOM组分进行了解析,从光谱学角度明...