Distribution characteristics of ammonia-oxidizing bacteria in the Typha latifolia constructed wetlands using fluorescent in situ hybridization(FISH)

A molecular biology method, fluorescent in situ hybridization（FISH）, in which the pre-treatment was improved in allusion to the media of the constructed wetlands（CW）, e.g. the soil and the grit, was used to investigate the vertical distribution characteristics of ammonia-oxidizing bacteria（AOB） quantity and the relation with oxidation-reduction potential（ORP） in the Typha latifolia constructed wetlands under three different Ioadings in summer from May to September. Results showed that the quantity of the AOB decreased in the Typha latifolia CW with the increase of vertical depth. However, the AOB quantity was 2-4 times the quantity of the control in the root area. Additionally, ORP in the rhizosphere was found to be higher than other areas, which showed that Typha latifolia CW was in an aerobic state in summer when using simulated non-point sewage at the rural area of Taihu Lake in China and small town combined sewage.     

PO4^3-和柠檬酸对稀土元素在小麦体内积累和分异的影响

基于营养液培养,添加外源稀土和ICP-MS分析技术,研究了无机配体PO43-(Pi)及有机配体柠檬酸(Cit)对小麦器官中稀土元素积累和分异的影响.结果表明,不同Pi水平对小麦根中的稀土总含量(∑REE)影响较小,但显著降低叶中∑REE含量;而不同Cit水平对小麦根、叶中∑REE含量都有明显降低作用.对照植物(无Pi、Cit添加)中,稀土元素在小麦根中具有中稀土(MREE)富集及M-型四重效应分布特征,叶中有重稀土(HREE)富集及W-型四重效应分布特征.不同Pi处理对四重效应无明显作用,但进一步加强HREE在小麦叶片中的富集.添加柠檬酸使对照植物根和叶中的分异有逐渐减弱的趋势,在高浓度处理时(Cit≥150μmol.L-1),小麦根和叶中出现轻稀土(LREE)富集.     

连州电厂湿法烟气脱硫系统的综合评价

从技术性能、经济性能两方面对连州电厂的广东省首套石灰石 /石膏湿法烟气脱硫系统进行了全面的评价     

UV/TiO_2膜深度处理垃圾渗滤液的研究

研究了以固定相TiO2为催化剂光催化降解垃圾渗滤液中有机污染物的可行性。试验了制备TiO2膜的适宜条件以及光照时间等各种因素对COD的去除率和UV335脱色率的影响。研究表明,COD为418mg/L的垃圾渗滤液经400W高压汞灯光照30min,COD的去除率和UV335脱色率分别为44.3%和75.0%。光照时间60min时,COD的去除率和UV335脱色率可提高至54%和90%。光照30min后与活性炭柱联用,COD的去除率和UV335脱色率分别提高到68.3%和84.6%。     

Interfacial effects of suspended particles on biodegradation of N (2,4 dimethyl phenyl) N'' methylformamidine hydrochloride and dibutyl phthalate in waters

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景观及视觉影响评价初探

介绍了国内外开展景观与视觉影响评价的情况和意义 ,提出了景观与视觉影响评价的基本概念、步骤、内容和方法 ,介绍了一种较为简便、实用的用于景观与视觉影响评价的定量方法。提出了进行这项工作的难点问题及设想建议。     

典型北方高碱度微污染水体强化混凝的示范研究

以高碱度、受有机物污染的典型北方水体为例,探索适宜的强化混凝技术.在水质调查的基础上,提出适合水质特征的强化混凝目标.研究了高碱度水体强化混凝技术方法.研究表明,可以通过3条技术途径提高水体中有机物的去除效率.其一在混凝前优化pH,促进絮凝剂水解形成中聚体,AlCl3在pH 6左右,FeCl3在pH 5左右时,有机物去除率可以提高一倍左右;其二是强化沉淀软化;其三是絮凝剂优化.结合我国实际情况,通过对传统絮凝剂进行改性,研制出了适合我国北方水质特征的高效絮凝剂,能较传统絮凝剂将有机物去除率提高30%以上.     

Prenatal diagnosis of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency by steroid analysis in the amniotic fluid of mid-pregnancy: Comparison with HLA typing in 17 pregnancies at risk for CAH

Amniotic fluid (AF) levels of 17-hydroxyprogesterone (17OHP) and testosterone (T) were determined at 16–17 weeks in 17 pregnancies at risk for CAH and results compared to 75 normal controls. The fetus was predicted to be unaffected in 12 cases on the findings of normal AF levels of both 17OHP and T and the latter allowed a correct prediction of fetal sex in all instances. HLA typing confirmed normality in 12 cases revealing 5 carriers, 5 homozygous normal and 2 indeterminate. Steroid levels of the 2 groups were similar. Three fetuses were predicted to be CAH affected on unambiguously high levels of 17OHP and T (in female only). HLA typing was in agreement, and the diagnosis was confirmed in 2 abortuses and a female newborn by physical and hormonal studies. In the last 2 cases AF levels of OHP and T were normal but HLA (A/B/C) genotypes were identical to the CAH affected siblings. Normal physical and hormonal findings in the 2 aborted fetuses would exclude the possibility of an in utero virilizing form of CAH. The discrepancy could be explained on the basis that the fetuses had an allelic form of 21-hydroxylase deficiency or on the basis of recombination (not fully tested). It is concluded that a fully informative prenatal diagnosis of CAH should not rely entirely on HLA typing but on hormonal studies.     

南京北郊冬夏季大气PM2.5中水溶性有机碳的研究

为研究南京北郊大气PM_(2.5)中水溶性有机碳(WSOC)的浓度及来源特点,在冬、夏季分别采集PM_(2.5)样品,还同步收集臭氧(O_3)浓度与相对湿度(RH)数据,分析了PM_(2.5)、有机碳(OC)、水溶性有机碳(WSOC)浓度特征,并对WSOC冬、夏季来源及其二次来源差异进行了探讨.结果显示,南京北郊冬季大气污染水平明显高于夏季且来源更复杂,与冬季静稳的天气条件及化石燃料和生物质燃烧排放较严重有关.冬季PM_(2.5)平均值为(136.7±42.4)μg·m~(-3),OC、WSOC浓度分别为(13.4±4.4)、(8.5±3.1)μg·m~(-3);夏季PM_(2.5)、OC、WSOC平均浓度分别为(61.5±14.6)、(6.7±2.1)、(4.6±1.7)μg·m~(-3).冬、夏季WSOC/OC值分别为67%±20%、69%±13%,且二次有机碳(SOC)与WSOC显著正相关,说明二次来源对WSOC有显著影响.冬季WSOC与O_3的负相关性不显著,与RH显著正相关;而夏季WSOC与O_3、RH的相关性正好与冬季相反,说明冬、夏季二次WSOC形成途径存在差异.冬季二次WSOC可能主要来自液相氧化,夏季可能主要来自光化学氧化.通过主成分因子分析法进一步确定南京北郊冬、夏季WSOC分别主要来源于二次来源和生物质燃烧、汽车尾气和扬尘.     

Simultaneous determination of dissolved organic nitrogen, nitrite, nitrate and ammonia using size exclusion chromatography coupled with nitrogen detector

Accurate quantification of dissolved organic nitrogen (DON) has been a challenge due to the cumulative analytical errors in the conventional method via subtracting dissolved inorganic nitrogen species (DIN) from total dissolved nitrogen (TDN). Size exclusion chromatography coupled with an organic nitrogen detector (SEC-OND) has been developed as a direct method for quantification and characterization of DON. However, the applications of SEC-OND method still subject to poor separations between DON and DIN species and unsatisfied N recoveries of macromolecules. In this study, we packed a series of SEC columns with different lengths and resin materials for separation of different N species and designed an independent vacuum ultraviolet (VUV) oxidation device for complete oxidation converting N species to nitrate. To guarantee sufficient N recoveries, the operation conditions were optimized as oxidation time ≥ 30 min, injection mass (sample concentration × injection volume) < 1000 µL × mg-N/L for macromolecular proteins, and neutral pH mobile eluent. The dissolved O₂ concentration in SEC mobile phase determined the upper limit of VUV oxidation at a specific oxidation time. Compared to conventional HW50S column (20 × 250 mm), HW40S column (20 × 350 mm) with mobile phase comprising of 1.5 g/L Na₂HPO₄·2H₂O + 2.5 g/L KH₂PO₄ (pH = 6.85) could achieve a better separation of DON, nitrite, nitrate, and ammonia. When applied to river water, lake water, wastewater effluent, groundwater, and landfill leachate, the SEC-OND method could quantify DON as well as DIN species accurately and conveniently even the DIN/TDN ratio reached 0.98.