挥发性有机污染物排放控制标准制订中的关键技术问题研究

研究分析了挥发性有机污染物排放标准制订中4个关键技术问题:污染因子选择、控制指标确定、限值的确定以及技术管理措施.结果表明,应根据毒性和光化学反应性选择污染因子;确定控制指标应既考虑有组织控制指标,又考虑无组织的控制指标;确定排放限值应明确是基于控制技术还是基于健康风险;同时制定技术管理措施以通过源头和过程控制挥发性有机污染物排放.     

杭州市典型企业废水中挥发性有机物排放特征及其评价

以10家杭州市典型企业进出口废水为调查对象,用顶空气相色谱质谱法测定77种挥发性有机物(VOCs),分析其排放特征,并对监测结果进行评价.结果表明,进口废水共定量检出22种VOCs,检出质量浓度范围为7~3.39×106μg·L-1;出口废水共定量检出14种VOCs,检出质量浓度范围为16~6.82×104μg·L-1.就行业而言,香精香料制造企业进出口废水VOCs检出的质量浓度最高.以《污水综合排放标准》(GB 8978-1996)三级排放标准为评价标准时,1号企业出口废水检出甲苯质量浓度为2.45×103μg·L-1,超过标准限值.以挥发性有机物的水介质排放环境目标值(DMEG WH)为标准时,3号企业出口废水检出的正丁醇、异丙醇、丙酮质量浓度均超过它们各自的水介质排放环境目标值.     

第二届挥发性有机污染物(VOCs)检测分析、减排控制、环境政策研究专辑征稿通知

挥发性有机物污染对生态、环境、健康产生了重要的影响,从国家层面上VOCs已经被列为重点控制的污染物,对挥发性有机污染物的减排与控制有着迫切的需求,有关挥发性有机污染的研究已经引起政府、地方、企业和科研人员密切的关注。     

DOM纳滤膜污染及对膜截留卡马西平性能的影响

研究了天然原水中溶解性有机物(DOM)对HL和ESNA1-K两种纳滤膜造成的膜污染及其对膜截留卡马西平(CBZ)性能的影响.结果表明,DOM的存在造成了严重的膜污染和通量衰减.膜污染对CBZ截留率的影响与膜本身的特性和污染物特性有关,DOM通过在膜表面形成污染滤饼层和进入膜孔内部造成的膜孔堵塞,影响弱疏水性的CBZ从水中的分离,青草沙水库原水中的DOM引起的膜污染提高了两种纳滤膜对CBZ的截留效果,而太湖DOM造成的膜污染会降低CBZ的截留效果.研究还发现,中等相对分子质量(1 500~10 000)有机物会紧密地黏附在膜表面形成滤饼层,从而改变膜表面的疏水性能,小分子主要通过进入膜孔导致膜孔径堵塞.滤饼层的疏水性和浓差极化作用以及膜孔径的堵塞造成膜通量衰减并影响CBZ去除率.应用XDLVO理论对DOM造成的膜污染的分析结果表明,太湖DOM的疏水性明显强于青草沙DOM,其分子间的聚合自由能更负,与膜的黏附自由能更负,因而造成的膜污染和通量衰减更严重.     

四环素抗性基因在人工湿地中的去除及累积

以垂直潜流人工湿地系统为试验装置,考察了猪场养殖废水中四环素类抗生素抗性基因(tetW、tetM和tetO)在人工湿地中的去除及累积情况.结果表明,养猪废水中的3种抗性基因均有检出且含量较高,tetW、tetM和tetO的平均绝对含量分别为1.07×1010、4.03×1010和4.92×1010copies.L-1.通过湿地系统处理后,水体中抗生素抗性基因绝对拷贝数和相对表达量均明显降低,tetW、tetM和tetO的平均去除率分别为95.73%、92.21%和95.05%.在系统运行末期,湿地表层土壤和底层土壤中tetW、tetM和tetO的绝对拷贝数和相对表达量均有明显的升高,并且抗性基因在表层土壤中的累积水平高于底层土壤.因此,人工湿地系统可有效降低养猪废水中抗生素抗性基因的绝对及相对含量水平,系统的运行条件可对抗生素抗性基因在湿地系统中的积累产生影响.     

闽南城市区域空气中挥发性有机物的污染特征

采用美国EPA TO-15的方法,研究了2011年3月份闽南城市区域空气中VOCs的含量及其污染特征。结果表明:1)漳州工业区空气的VOCs浓度为200.5μg/m3,污染较为严重;厦门交通干道VOCs浓度为74.0μg/m3,泉州商住区的VOCs浓度77.1μg/m3,污染较轻。2)漳州工业区采样点TOP5占TVOCs的比例最高,达77.3%;厦门交通干道与泉州商住区两采样点的TOP5占TVOCs的比例相近,分别为64.1%和62.0%。在所有的采样点中出现的TOP5组分比较集中,主要包括甲苯、苯、二氯甲烷、异丙醇、乙酸乙酯、1,1-二氯乙烯、萘等。3)机动车尾气的排放、工业溶剂的挥发和废气排放可能是厦漳泉三地大气VOCs的主要排放源。4)厦漳泉的BTEX主要来源于汽车尾气和汽油挥发;其中厦门和泉州BTEX浓度相比较处在较低污染水平,漳州处在中等水平。     

Influence of dissolved organic matter character on mercury incorporation by planktonic organisms：An experimental study using oligotrophic water from Patagonian lakes

Ligands present in dissolved organic matter （DOM） form complexes with inorganic divalent mercury （Hg^2＋） affecting its bioavailability in pelagic food webs. This investigation addresses the influence of a natural gradient of DOM present in Patagonian lakes on the bioaccumulation of Hg^2＋ （the prevailing mercury species in the water column of these lakes） by the algae Cryptomonas erosa and the zooplankters Brachionus calyciflorus and Boeckella antiqua. Hg^2＋ accumulation was studied through laboratory experiments using natural water of four oligotrophic Patagonian lakes amended with^197Hg^2＋. The bioavailability of Hg^2＋ was affected by the concentration and character of DOM. The entrance of Hg^2＋ into pelagic food webs occurs mostly through passive and active accumulation. The incorporation of Hg^2＋ by Cryptomonas, up to 27% of the Hg^2＋ amended, was found to be rapid and dominated by passive adsorption, and was greatest when low molecular weight compounds with protein-like or small phenolic signatures prevailed in the DOM. Conversely, high molecular weight compounds with a humic or fulvic signature kept Hg^2＋ in the dissolved phase, resulting in the lowest Hg^2＋ accumulation in this algae. In Brachionus and Boeckella the direct incorporation of Hg from the aqueous phase was up to 3% of the Hg^2＋ amended. The dietary incorporation of Hg^2＋ by Boeckella exceeded the direct absorption of this metal in natural water, and was remarkably similar to the Hg^2＋ adsorbed in their prey. Overall, DOM concentration and character affected the adsorption of Hg^2＋ by algae through competitive binding, while the incorporation of Hg^2＋ into the zooplankton was dominated by trophic or dietary transfer.     

Electrochemical and spectroscopic characteristics of dissolved organic matter in a forest soil profile

Dissolved organic matter （DOM） represents one of the most mobile and reactive organic compounds in ecosystem and plays an important role in the fate and transport of soil organic pollutants, nutrient cycling and more importantly global climate change. Electrochemical methods were first employed to evaluate DOM redox properties, and spectroscopic approaches were utilized to obtain information concerning its composition and structure. DOM was extracted from a forest soil profile with five horizons. Differential pulse voltammetry indicated that there were more redox-active moieties in the DOM from upper horizons than in that from lower horizons. Cyclic voltammetry further showed that these moieties were reversible in electron transfer. Chronoamperometry was employed to quantify the electron transfer capacity of DOM, including electron acceptor capacity and electron donor capacity, both of which decreased sharply with increasing depth. FT-IR, UV-Vis and fluorescence spectra results suggested that DOM from the upper horizons was enriched with aromatic and humic structures while that from the lower horizons was rich in aliphatic carbon, which supported the findings obtained by electrochemical approaches. Electrochemical approaches combined with spectroscopic methods were applied to evaluate the characteristics of DOM extracted along a forest soil profile. The electrochemical properties of DOM, which can be rapidly and simply obtained, provide insight into the migration and transformation of DOM along a soil profile and will aid in better understanding of the biogeochemical role of DOM in natural environments.     

不同聚硅酸硫酸铁去除有机物及膜污染的影响

采用腐植酸、苯胺、海藻酸钠、羟丙基甲基纤维4种有机物分别模拟天然有机物中的疏水酸性、疏水碱性、亲水带电性及亲水中性4种有机物,使用"聚硅酸+Fe3+"、"聚硅酸+聚硫酸铁(PFS)"、"聚硅酸+Fe2++H2O2"3种不同聚合方式的聚硅酸硫酸铁(PFSS)进行水处理,并将絮凝处理后的废水上清液通过微滤膜,考察不同聚合方式PFSS对有机物的去除及膜污染的影响。实验结果表明:4种有机物最难去除的是苯胺和海藻酸钠,羟丙基甲基纤维素其次,腐殖酸最易去除;以"聚硅酸+PFS""、聚硅酸+Fe2++H2O2"方式聚合的絮凝剂与"聚硅酸+Fe3+"方式聚合的絮凝剂相比,去除产生可逆污染的腐植酸的比例相差不大,但去除产生不可逆污染加大的苯胺、海藻酸钠、羟丙基甲基纤维素3种有机物的比例明显增大,膜污染率虽然相对稍大,但更加可逆。     

溶解性有机质对土壤呼吸作用的影响

本文采用室内培养方法研究了水稻秸秆腐解产生的DOM对温州周边地区两种不同土壤的呼吸强度的影响。结果表明,腐解初期的DOM能促进土壤的呼吸作用,而腐解后期的DOM则抑制土壤的呼吸作用。