基于折减系数的地下水污染风险评价方法探究

地下水污染风险评价对地下水污染防治与地下水合理开发利用具有重要意义.目前国内外最常用的是基于DRASTIC模型结合污染荷载的地下水污染风险评价方法.本文对比总结了国内外地下水污染风险评价方法体系,针对目前方法体系的不足,提出基于折减系数的评价体系,通过引进"折减系数"来表征污染物在包气带中的迁移转化过程,最后以石家庄滹沱河冲洪积扇平原区为例进行了地下水污染风险评价.结果表明,研究区污染风险最高的地区多为工业区;其次是滹沱河河道及周边地区地下水污染风险较高,原因主要是该地区包气带基本以砂性土为主,且排污河污染物随河水常年下渗;农业污染源排放量较小,农田区污染风险最低.该方法体系实现了污染物由地表到达地下的衰减过程量化,且简便易操作.此外,该方法把污染物毒性与污染物到达地下水面的量放在同一层次,使得地下水污染风险评价的结果更具说服力.     

软锰矿浆烟气脱硫动力学研究

研究了软锰矿浆烟气脱硫工艺SO2与软锰矿反应的动力学特征,考察了搅拌强度、温度和SO2浓度等因素对反应速率的影响,计算出反应活化能和反应级数,建立了揭示SO2与软锰矿反应动力学特征的锰浸出速率方程.     

喷射鼓泡反应器在软锰矿烟气脱硫中的应用

对喷射鼓泡反应器结构及反应器内传质、反应状态进行了分析 ,并对脱硫浸锰进行了研究。结果表明 ,采用喷射鼓泡反应器可以获得好的脱硫率和锰浸出率 ,同时该反应器将SO2 吸收和锰浸出放在一个设备中进行 ,省去了外循环系统 ,故该装置系统简单、紧凑 ,投资省 ,脱硫效率高     

软锰矿微生物催化氧化烟气脱硫

利用软锰矿与微生物联合催化氧化烟气SO₂.分别选取氧化亚铁硫杆菌（T. ferrooxidans菌）和锰氧化细菌,研究微生物对SO^2-₃的氧化性能和恢复体系中Mn（Ⅱ）和Fe（Ⅲ）的活性性能.采用紫外线诱变法,选育出了对SO^2-₃和Fe²⁺转化效率高T. ferrooxidans菌的优势菌株,对Fe²⁺的完全氧化时间缩短为约24 h.通过分析细菌与软锰矿联合催化氧化脱除SO₂的脱硫效率变化、液相中SO^2-₃离子的变化,以及二者的关系,探讨了细菌在软锰矿脱硫体系中所起的作用,并用透射电子显微镜观察了反应前后锰氧化细菌的形态变化.结果表明Fe²⁺与T. ferrooxidans菌共同存在时,T. ferrooxidans菌对SO₃^2-的转化速率可达到0.015?3　g/(L·min),优于化学氧化.T. ferrooxidans菌和锰氧化菌联合软锰矿脱硫实验结果表明,细菌对软锰矿脱硫存在强化作用;锰氧化细菌促进脱硫存在适应期,T. ferrooxidans菌和锰氧化菌存在协同效应,微生物可以完成铁锰催化剂的再生循环.     

Antioxidant and modulatory role of Chlorophytum borivilianum against arsenic induced testicular impairment

Arsenic has a suppressive influence on spermatogenesis and induces impairment in male reproductive system due to oxidative stress. The present study was aimed to test the arsenic induced toxicity and protection by Chlorophytum borivilianum. The effect of sodium arsenite (4 mg/(kg body weight (bw). day)) via double distilled water without or with C. borivilianum (800 mg/(kg bw. day)) was evaluated in Swiss albino mice for 30 days. The radical scavenging activity of the aqueous C. borivilianum root extract was measured using DPPH (1,1-diphenyl-2-picryl hydrayzyl) radical. Qualitative assessment of various cell types in the testis, sperm count and motility, testicular activity of lipid peroxidation (LPO), reduced glutathione (GSH), acid and alkaline phosphatase, cholesterol and serum testosterone were monitored. Arsenic treatment showed a significant increase in LPO, acid and alkaline phosphatase, cholesterol and decrease in sperm count, sperm motility, GSH and serum testosterone. Combined treatment showed significant decrease in LPO, acid and alkaline phosphatase, cholesterol and elevation in sperm count, sperm motility, GSH and serum testosterone. Testicular histopathology showed that C. borivilianum had reduced degeneration of germ cell in the seminiferous tubules and loss of sperms induced by arsenic intoxication. The results thus led us to conclude that administration of C. borivilianum root extract is found to be protective against arsenic induced toxicity.     

软锰矿浆烟气脱硫反应器内气-液两相流的数值模拟

为了揭示喷射鼓泡反应器内流动结构和气液分散特性,为该反应器的优化设计提供理论指导,应用计算流体动力学(CFD)方法对反应器内气液两相流动结构进行了数值模拟,并提出气含率方差概念用于定量描述气相分散程度。着重考虑了搅拌转速和表观气速对通气功率、整体气含率和气相分散程度的影响。结果表明:流场的重要特征与前人的类似实验结果和数值模拟结果一致;数值模拟能很好地捕捉了六直叶圆盘涡轮桨的气穴现象;气穴现象会导致通气功率降低且不利于气液混合;整体气含率随转速和表观气速的增加而增大,但从气液混合与能耗的的角度考虑,搅拌转速宜采用200～300 r/min,表观气速为0.04～0.06 m/s。     

厌氧-混凝-高级氧化对转运站污水恶臭处理效果

以总还原硫(TRS)为考察指标,分析了基于厌氧-混凝-高级氧化工艺的中试系统各处理单元对转运站污水中恶臭物质的处理效果。转运站污水中,TRS总量为0.602 mg/L水,而经过厌氧、混凝、高级氧化等处理单元后依次为4.167,3.513,0.168 mg/L水。厌氧对含硫有机物的降解是恶臭物质产生的重要过程,混凝过程对污水恶臭去除作用很小。相比于混凝出水,高级氧化对恶臭物质去除率在95%以上。     

太阳辐射减弱对灌浆期冬小麦光合特性及膜脂过氧化水平的影响

以扬麦13为供试材料,通过大田试验方法研究了太阳辐射减弱对冬小麦灌浆期光合生理特性、保护酶系统及膜脂过氧化水平的影响. 设置了5个太阳辐射减弱处理,各处理的太阳辐射强度分别为自然光照的100%(CK),60%,40%,20%和15%. 结果表明:太阳辐射减弱导致冬小麦叶片的光合生理特性发生明显变化,表现为净光合速率(P_n)减少,气孔限制值(L_s)和蒸腾速率(T_r)显著降低,但胞间CO₂浓度(C_i)却逐渐上升;随着太阳辐射减弱程度的增加,冬小麦叶片的CAT(过氧化氢酶),SOD(超氧化物歧化酶)和POD(过氧化物酶)活性均显著增加,表现出较高的抗性,但MDA(丙二醛)含量及EC(电导率)降低,说明太阳辐射减弱未使作物膜系统受到明显伤害;在太阳辐射减弱条件下,冬小麦光合色素的含量增加较明显,但w(Chla)/w(Chlb)下降,对太阳辐射中偏向短波部分波段的吸收能力增强. 综上所述,在太阳辐射减弱条件下,冬小麦灌浆期通过提高保护酶系统的活性避免细胞膜系统的膜脂过氧化伤害,同时提高w(Chlb)以增强光能的利用能力. 尽管如此,由于太阳辐射能量的不足,作物的P_n仍持续下降,且主要是由非气孔因素引起.      

Effect of latex material on antioxidant enzymes,lipid peroxidation,DNA damage,and chromosomal aberration

Cell integrity is affected by oxidative stress when the production of active oxidants overwhelms antioxidant defense mechanisms. Latex, a natural polymer obtained from Hevea brasiliensis, is used in medical industry for manufacturing surgical gloves, urinary catheters, and dental dams. The aim of this study was to evaluate the effects of latex material on oxidative stress by in vivo and in vitro methods. In addition, the material was screened for its ability to induce any chromosomal aberrations (CAs) by in vitro method. In vivo studies were carried out with implanted latex material onto subcutaneous tissue of various batches of experimental Wistar rats. At the end of experimental period, animals were anesthetized, blood was collected for serum analysis, and sacrificed. Liver was excised for the determination of antioxidant enzymes and lipid peroxidation (LPO). Subcutaneous tissues were obtained for the extraction of genomic DNA from implanted animals and checked for the presence of 8-hydroxy-2-deoxyguanosine (8-OHdG), considered an indicator of DNA damage. Simultaneously, in vitro studies were carried out using fresh liver and subcutaneous tissue obtained from Swiss albino mice treated with physiological saline extract of latex material. For the estimation of both in vitro and in vivo oxidative stress, 10% liver homogenate was assessed for stress indicators like reduced glutathione, glutathione reductase, glutathione peroxidase, LPO and protein content. The results of both in vivo and in vitro studies indicated that the chemical leachents from the latex material did not significantly affect LPO and the levels of antioxidant enzymes. There was also no significant increase in 8-OHdG content due to the presence of implanted latex material. Finally, the results of in vitro CA test and G banding indicated that extracts of test material did not induce any chromosomal abnormalities.     

软锰矿浆催化氧化烟气SO2的动力学初探

对高液固比软锰矿浆与烟气SO2产酸过程进行了研究,在考察液固比、氧浓度和pH值等对反应过程影响的实验基础上,认为高液固比下主要发生的是软锰矿浆对烟气SO2的催化氧化生成硫酸的反应,并认为在[O2]控制区内,反应可以分为线性阶段和幂函数2个反应阶段.