环境雌激素o,p′-DDT和抗雌激素氟维司群对斑马鱼胚胎的复合效应

为探究雌激素与抗雌激素的复合效应,将斑马鱼(Danio rerio)的胚胎暴露于o,p′-DDT和氟维司群2种典型的环境内分泌干扰物中,考察胚胎孵化率、孵化时间和总畸形率,并用实时荧光定量PCR技术检测Vtg1、Vtg2和ERα等雌激素效应相关基因的mRNA转录水平.结果显示,与单一化合物的暴露相比,o,p′-DDT和...     

Characterization of soil low-molecular-weight organic acids in the Karst rocky desertification region of Guizhou Province, China

Soil low-molecular-weight (LMW) organic acids play important roles in the soil-forming process and the cycling of nutrients in Karst regions. In this study, we quantified the contents of LMW organic acids (including lactate, acetate, formate, malate, and oxalate) in soil solution over the Karst region of Guizhou Province, China using ion chromatography. The concentration of total LMW organic acids in topsoil solution ranged from 0.358 to 1.823 μmol·g^-1, with an average of 0.912 μmol·g^-1. The mean concentrations of lactate, acetate, formate, malate, and oxalate were 0.212±0.089, 0.302±0.228, 0.301±0.214, 0.014±0.018 and 0.086±0.118 μmol·g^-1, respectively. There were also significant difference in the contents of these acids among four phases of rocky desertification, and their concentrations decreased with the aggravation of rocky desertification. The concentrations of the LMW organic acids were significantly positive correlated each other. Significant positive correlations were also observed among individual LMW organic acids in soil solution, and between them and soil available P, available K, exchangeable Ca, respectively. Furthermore, the concentrations of LMW organic acids were significantly positively correlated with inorganic anions (chlorides, nitrates, and sulfates) in Karst topsoil solution. Therefore, the concentrations of soil LMW organic acids might be one of driving force in the Karst rock desertification process in Guizhou Province.     

河源城南污水处理厂尾水深度处理效果的研究

河源市城南污水处理厂利用垂直流人工湿地对该厂A2-O工艺处理的尾水进行深度处理,研究了人工湿地对尾水中TN、NH4+-N、TP、COD、BOD5的去除效果。结果表明:人工湿地对污水处理厂尾水具有较好的深度处理效果,垂直流人工湿地处理系统对尾水中TN、NH4+-N、TP、COD和BOD5平均去除率分别达到97.4%、97.8%、95.06%、91.87%和95.87%以上,其出水水质基本达GB 18918—2002《城镇污水处理厂污染物排放标准》一级A标准,地表水Ⅲ类标准。     

Rapid dephosphorylation of glyphosate by Cu-catalyzed sulfite oxidation involving sulfate and hydroxyl radicals

Environmental Chemistry Letters - Glyphosate is a broad-spectrum toxic herbicide that has entered the environment. Advanced oxidation processes efficiently remove various persistent organic...     

基于NORTA相关随机数的岩质边坡可靠性仿真评估

随机因素的合理表征是边坡可靠性评估的关键。NORTA方法是一种利用多维正态随机向量变换实现具有任意分布类型和可行相关矩阵的多维随机数生成的快速算法。以秀茂坪岩质边坡稳定可靠性为例,采用NORTA方法生成具有指定概率信息(边缘分布和相关系数)的相关随机数,利用MC仿真估计典型工况下的岩坡失稳概率,并在这一过程中探讨NORTA-MCS方法的限制、仿真结果的随机性以及通过控制变异系数估算仿真样本个数的途径。结果表明:相比自然状态下的秀茂坪岩坡,忽略相关性的岩坡失稳概率增加显著;而且随着粘聚力和内摩擦角间以及张力裂缝深度和充水程度间相关系数代数值的增大,秀茂坪岩坡的失稳概率也逐渐增大。     

多级A/OVTBR组合工艺处理焦化废水

采用水解酸化、多级A/O垂直折流生物膜反应器(vertical tubulant biological reactor,VTBR)、混凝和Fenton氧化组合技术对实际焦化废水进行处理。其中水解酸化预处理阶段提高了废水可生化性,混凝降低了生化处理的有机负荷,一级A/O VTBR以脱碳为主,二级A/O VTBR主要脱碳和脱氮,三级好氧VTBR强化对氨氮的去除,Fenton氧化则对生化出水进行深度处理。试验结果表明:在进水ρ(COD)为3 000～3 500 mg/L,ρ(BOD5)为1 212 mg/L,ρ(NH3-N)为109 mg/L条件下,保持好氧段ρ(DO)为3～7 mg/L,缺氧段ρ(DO)<1 mg/L,总停留时间HRT 56 h,该工艺对COD、BOD5、NH3-N的去除率分别为98%、99%、95%,出水达GB8978-1996《污水综合排放标准》中的一级排放标准。     

蜡染印花工艺废水处理设计及运行

设计运行了整个蜡染印花废水处理工程,皂化脱蜡废水松香回收新工艺,即采用两步调pH法-周边自重力进水法,回收率可达98%以上;机械洗蜡废水分流后经双级气浮处理,蜡回收率和处理水回用率可达90%以上;洗蜡废水经蜡回收后出水与其他废水混合后经初级混凝沉淀-水解酸化-好氧生化(A/O工艺)-辐流沉淀组合工艺处理,出水ρ(COD)均值约为130 mg/L,ρ(NH3-N)为3.36 mg/L,然后进入市政管网进行深度处理。     

Preparation and assay of C-glucosyltransferase from roots of Pueraria lobata

C-glucosyltransferase (EC 2.4.1.X) is one of the key enzymes for the biosynthesis of puerarin. This paper describes the methodology in purification and assay of the enzyme for the first time in Puerarin lobata (Wild.) Ohwi. C-glucosyltransferase from roots of P. lobata was extracted and partially purified by (NH4)2SO4 saturation. The effects of pH, temperature, and substrate concentration on the activity of the enzyme were investigated. The properties of the puerarin produced by C-glucosyltransferase were studied by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). The peak activity of C-glucosyltransferase was detected in fraction of by 80% saturation of (NH4)2SO4 and the optimal conditions for enzymatic reaction were 35.5 micromol l(-1) of isoliquiritigenin and 560 micromol l(-1) of UDP-G at pH 8.1, 28 degrees C for 1 h. Mn2+ at 1 mmol l(-1) and Al3+ at 1 mmol l(-1) increased the enzyme activity, while Mg2+ inhibited its activity. The enzyme activity in Nicotiana tabacum and P. lobata were detected under the above assay conditions. Higher activity was found in roots than in leaves and stems of P. lobata, while no enzyme activity was detected in leaves of N. tabacum. It was the first time that activity of C-glucosyltransferase, which transforms isoliquiritigenin to puerarin, was detected in P. lobata.     

预处理-气浮-氧化沟工艺处理再生纸废水

介绍了预处理-气浮-氧化沟工艺在再生纸废水处理工程中的应用。运行结果表明:该工艺处理效果稳定,耐冲击负荷能力强,进水ρ(COD)、ρ(BOD5)、ρ(SS)分别为1542,654,2254mg/L时,出水分别为77,38,22mg/L,系统出水水质达GB3544-2001《造纸工业水污染物排放标准》。     

Enhanced NOx removal from flue gas by an integrated process of chemical absorption coupled with two-stage biological reduction using immobilized microorganisms

An integrated process of metal chelate absorption coupled with two stage bio-reduction using immobilized cultures has been proposed to continuously removal of NO_x, and the effects of SO₂, NO and O₂ concentration, gas/liquid flow rate on NO_x removal efficiency were investigated. Although nitrogen-containing components, such as Fe(II)EDTA-NO, NO₂^? and NO₃^? in the scrubbing solution, inhibited the bio-reduction of Fe(III)EDTA obviously, it was feasible to abate the inhibition effect by using the two stage bio-reduction system, and thus to improve NO_x removal efficiency. The removal efficiency decreased slowly with the increase of SO₂, O₂, NO concentration and gas flow rate, and increased with the increase of liquid flow rate. Continuously operating for 18 days, a high removal efficiency around 95% was reached by using the two-stage bio-reduction system with immobilized microorganisms, while the value decreased to 85% after 5 days of operation by using the suspended microorganisms, at a constant gas flow rate of 60 L/h containing 424–450 mg/m³ NO, 2428–2532 mg/m³ SO₂ and 3% O₂.