负载AsOB离子交换纤维FFA-1去除水中三价砷

对比两组填充了离子交换纤维FFA-1的固定床反应器（R1和R2）的运行处理效果,研究负载功能微生物的离子纤维组合工艺对不同浓度As（III）的去除能力.研究结果表明接种了三价砷氧化菌（AsOB）的R1能够长期稳定并高效地去除不同浓度（1~10 mg·L^-1）As（III）.未接种AsOB的R2反应器初期无法去除As（III）,随着微生物逐步侵入R2反应器,7 d后R2反应器As（III）去除率逐渐与R1接近.相对于一直稳定运行的R1反应器,每次提升进水中As（III）浓度后R2去除率呈现先下降后上升的趋势.同时,在运行过程中发现进水中NO₃^-和SO₄^2-等阴离子也会被R1和R2去除从而导致As（III）去除总量的下降.离子交换纤维FFA-1再生实验证实R1和R2中的纤维与原始的离子交换纤维FFA-1再生效果相当（再生率均达到90%以上）.进一步研究微生物种群结构在反应器中的变化发现离子交换纤维作为微生物载体可能是影响微生物种群结构的重要因素.本研究证实了功能微生物AsOB联合离子交换纤维可以作为一种高效去除地下水中三价砷的工艺,具有很好的应用前景.     

轻型汽车和汽车塑料配件涂装工艺过程的VOCs组分特征

通过采集和分析珠江三角洲(以下简称“珠三角”)地区轻型汽车和汽车塑料配件涂装工艺过程的VOCs样品,识别了上述两个行业不同涂装工艺过程的VOCs组分特征.结果表明:芳香烃(56.4%~75.5%)和OVOCs(11.0%~35.7%)为轻型汽车涂装工艺占比最大的两种VOCs组分;烷烃和烯炔烃在烘干工艺所占比重要高于喷涂工艺;1,2,4-三甲苯为电泳和面涂烘干工序的主要VOCs组分,间/对-二甲苯、乙酸丁酯、丙二醇甲醚醋酸酯分别为中涂、面涂和中涂烘干工序的主要VOCs组分.汽车塑料配件涂装工艺不同工序的VOCs组成相似,芳香烃(53.3%~58.3%)和OVOCs(40.9%~45.8%)为主要VOCs组成,甲苯、乙酸乙酯、乙酸丁酯等为主要VOCs组分.不同废气治理设施对汽车塑料配件涂装工艺VOCs组分会造成一定的影响.活性炭吸附治理设施处理后的主要VOCs组分为甲苯、乙苯和邻二甲苯等芳香烃组分,水喷淋治理设施则为乙酸乙酯、乙酸丁酯和丙二醇甲醚醋酸酯等OVOCs类组分.通过与其他研究对比,丙二醇甲醚醋酸酯作为原辅料和废气中的主要组分之一,在以往研究中并未识别出来,表明针对测试对象的原辅料与工艺信息的现场调研是开展VOCs组分特征及成分谱研究的基础工作,建议未来该方面研究加强对前期调研工作的重视.此外,建议关注行业发展趋势给VOCs成分谱研究带来的影响.     

Current status of indoor dust PBDE pollution and its physical burden and health effects on children

Environmental Science and Pollution Research - Polybrominated diphenyl ethers (PBDEs) are widely detected in indoor dust, which has been identified as a more important route of PBDE exposure for...     

Blood concentrations of lead,cadmium, mercury and their association with biomarkers of DNA oxidative damage in preschool children living in an e-waste recycling area

Reactive oxygen species (ROS)-induced DNA damage occurs in heavy metal exposure, but the simultaneous effect on DNA repair is unknown. We investigated the influence of co-exposure of lead (Pb), cadmium (Cd), and mercury (Hg) on 8-hydroxydeoxyguanosine (8-OHdG) and human repair enzyme 8-oxoguanine DNA glycosylase (hOGG1) mRNA levels in exposed children to evaluate the imbalance of DNA damage and repair. Children within the age range of 3–6 years from a primitive electronic waste (e-waste) recycling town were chosen as participants to represent a heavy metal-exposed population. 8-OHdG in the children’s urine was assessed for heavy metal-induced oxidative effects, and the hOGG1 mRNA level in their blood represented the DNA repair ability of the children. Among the children surveyed, 88.14% (104/118) had a blood Pb level >5 μg/dL, 22.03% (26/118) had a blood Cd level >1 μg/dL, and 62.11% (59/95) had a blood Hg level >10 μg/dL. Having an e-waste workshop near the house was a risk factor contributing to high blood Pb (r _s  = 0.273, p < 0.01), while Cd and Hg exposure could have come from other contaminant sources. Preschool children of fathers who had a college or university education had significantly lower 8-OHdG levels (median 242.76 ng/g creatinine, range 154.62–407.79 ng/g creatinine) than did children of fathers who had less education (p = 0.035). However, we did not observe a significant difference in the mRNA expression levels of hOGG1 between the different variables. Compared with children having low lead exposure (quartile 1), the children with high Pb exposure (quartiles 2, 3, and 4) had significantly higher 8-OHdG levels (β _Q2 = 0.362, 95% CI 0.111–0.542; β _Q3 = 0.347, 95% CI 0.103–0.531; β _Q4 = 0.314, 95% CI 0.087–0.557). Associations between blood Hg levels and 8-OHdG were less apparent. Compared with low levels of blood Hg (quartile 1), elevated blood Hg levels (quartile 2) were associated with higher 8-OHdG levels (β _Q2 = 0.236, 95% CI 0.039–0.406). Compared with children having low lead exposure (quartile 1), the children with high Pb exposure (quartiles 2, 3, and 4) had significantly higher 8-OHdG levels.     

Kinetic and mechanism studies of the ozonolysis of three unsaturated ketones

Reaction rate constants and products of 1-octen-3-one, 3-octen-2-one and 4-hexen-3-one with ozone were studied in a 100-L fluorinated ethylene propylene (FEP) Teflon film bag using absolute rate method at 298 ± 1 K and atmospheric pressure. The rate constants were (1.09 ± 0.12) × 10^?17, (3.48 ± 0.36) × 10^?17 and (5.70 ± 0.60) × 10^?17 cm³/(molecule?sec), respectively. According to the obtained rate constants, the effects of carbonyl were discussed. The carbonyl group in β position has a net withdrawing effect with respect to an olefinic bond, then causing the decline of rate constants. The quantum chemical calculation was used to explain the results of rate constants. The products of ozonolysis were mainly aldehydes, which have significant influence on the formation of SOA, and hence play an important role in the atmosphere. In this work, we detected the main products of reaction and proposed the reaction mechanism by combining the results of quantum chemical calculations. Atmospheric lifetime for three unsaturated ketones reacted with ozone was 36.4, 11.4 and 6.9 hr for 1-octen-3-one, 3-octen-2-one and 4-hexen-3-one, respectively.     

水平潜流人工湿地脱氮功效中植物的作用

为了研究芦苇(Phragmites australis)在收割期前/后、湿地床体内部各个区域内、一年四季中在水平潜流人工湿地脱氮效用所起的作用,实验设置了有/无植物2组平行反应器。结果表明,芦苇在收割前/后对于水平潜流人工湿地脱氮效果均有促进作用,植物地上部分氮吸收量占湿地脱氮量的10.2%。在芦苇收割前/后(5月~9月、10月~次年5月),芦苇湿地日均脱氮量分别是无植物湿地的1.55倍与1.11倍。高、矮芦苇不同组织中总氮浓度分布趋势一致,2种芦苇各组织含量分别为:穗(28.69 g/kg)>叶(13.69 g/kg)>茎(5.31 g/kg)、穗(28.06 g/kg)>叶(14.61 g/kg)>茎(8.46 g/kg)。在湿地的各个沿程区域,总氮、氨氮累加去除率变化趋势一致,并且从反应器前部到尾部呈上升趋势,从上部到下部呈下降趋势。有芦苇湿地的脱氮效用优于无植物湿地,且底部氮积累含量也较少。一年四季中有芦苇湿地在各个季节脱氮量是无植物湿地的1.06~1.47倍。     

潮汐流人工湿地对高污染河水的处理功效

为了研究潮汐流人工湿地对高污染河流污染物的去除效果及其影响因素,实验构建了潮汐流人工湿地系统。运行春夏两季以来,系统对TN、NH3-N、TP、COD和BOD5的平均去除率分别为49.14%、48.34%、79.40%、81.52%和83.39%;其中系统对TN和NH3-N的去除受到温度的影响,且温度变化对NH3-N去除效果的影响大于TN;在实验周期内,系统对TN、TP、COD和BOD5的去除均受进水污染负荷的影响,但却有着较好的抗负荷冲击能力;潮汐流人工湿地能够显著提高系统内溶解氧,使其不再成为去除污染物的限制性因素。     

复合人工湿地对高污染性河流营养物的去除

为了研究复合人工湿地对高污染性河流营养物的去除效果，在西安皂河人渭处建立了一座占地约13334m。包括5组不同复合人工湿地工艺的中试系统。经过1年的实验研究表明，复合型人工湿地对COD、BOD。和ss有很好的去除效果，其去除率最高分别为（82．4±7．2）％、（97．1±1．7）％和（94±2．7）％，对于脱氮除磷而言，以水力停留时间4．1d的复合湿地系列4的处理效果最佳，对TN、NH3-N和TP的年去除率达（79．4±14）％、（79．2±13．7）％和（82．3±12）％。氮的去除效果受温度季节性变化影响较大，夏季平均水温高于19℃有更好的处理效果，磷的去除效果受温度影响不大；NO2-、NO3-去除率呈现负增长，在湿地尾端出现了不同程度的积累。     

Hybrid constructed wetlands for highly polluted river water treatment and comparison of surface- and subsurface-flow cells

A series of large pilot constructed wetland （CW） systems were constructed near the confluence of an urban stream to a larger fiver in Xi＇an, a northwestern megacity in China, for treating polluted stream water before it entered the receiving water body. Each CW system is a combination of surface- and subsurface-flow cells with local gravel, sand or slag as substrates and Phragmites australis and Typha orientalis as plants. During a one-year operation with an average surface loading of 0.053 m3/（m2.day）, the overall COD, BOD, NH3-N, total nitrogen （TN） and total phosphorus （TP） removals were 72.7% ~ 4.5%, 93.4% ＋ 2.1%, 54.0% ＋ 6.3%, 53.9% ~ 6.0% and 69.4% ：t： 4.6%, respectively, which brought about an effective improvement of the fiver water quality. Surface-flow cells showed better NH3-N removal than their TN removal while subsurface-flow cells showed better TN removal than their NH3-N removal. Using local slag as the substrate, the organic and phosphorus removal could be much improved. Seasonal variation was also found in the removal of all the pollutants and autumn seemed to be the best season for pollutant removal due to the moderate water temperature and well grown plants in the CWs.     

国内外PM2.5源谱对比及其对空气质量模拟效果的影响

对比了国内外固定燃烧源、工业过程源、道路移动源和扬尘源等排放源PM_2.5成分谱之间的差异,并利用CMAQ（区域空气质量模型）模拟识别各PM_2.5成分谱之间的差异对空气质量模拟影响较大的排放源.结果表明:① 由于国内外发展水平、排放标准、采样分析条件以及排放源除尘设备等的差异,各排放源PM_2.5成分谱差异较大;② PM_2.5成分谱差异较大的源主要有燃煤电厂、水泥制造、重型柴油车和道路扬尘等,而差异较大的组分主要有SO₄2-、NO₃-和Ca等;③ 道路移动源源谱本地化对PM_2.5的模拟影响最大,其次为扬尘源和工业过程源,而固定燃烧源则相较最小,其中道路移动源源谱本地化模拟案例与基线的PM_2.5模拟质量浓度绝对差值为0.27μg/m3,各组分质量浓度差系数之和为52.60×10-3 μg/（m3·kg）,而固定燃烧源源谱本地化模拟案例PM_2.5模拟质量浓度绝对差值仅为0.10μg/m3,各组分之和为2.12×10-3 μg/（m3·kg）.研究显示,有必要采用统一的标准开展本地源成分谱测试工作,为源解析及模型模拟提供基础性数据,而从对空气质量模型模拟影响的角度出发,优先建立道路移动源本地化PM_2.5成分谱较为重要.