应用自动识别和定量系统评价两种污水再生工艺对微量有机污染物的去除效果

采用气质联用分析,并结合自动识别与定量系统(AIQS-DB)考察2种再生水厂采用的深度处理工艺对微量有机污染物的去除效果。结果表明,以污水为原水的膜生物反应器(MBR)+臭氧氧化+生物活性炭滤池(BAC)工艺用于再生水生产,MBR工艺对有机污染物的去除起主要作用;城市污水厂二级出水为原水的混凝沉降+浸没式超滤(SMF)/连续微滤(CMF)+部分反渗透(RO)+臭氧氧化工艺用于再生水生产,其SMF和CMF工艺段的膜截留作用均可有效消减有机污染物含量,SMF的效果优于CMF;2种工艺中采用的臭氧技术都能进一步加强部分物质的去除效果。气质联用结合AIQS-DB可用于再生水中污染物的筛查和不同污水再生工艺对微污染物消减效果的评价。     

人工湿地系统微生物去除污染物的研究进展

人工湿地污水处理系统具有净化效果显著、建设和运行费用低廉、管理简便等优点,近年来越来越受到人们的重视。人工湿地是利用介质、植物和微生物构成的复合系统来处理污水。微生物在人工湿地系统净化污水过程中发挥着重要作用。介绍了人工湿地系统中微生物去除污染物的研究进展,重点讨论了人工湿地对污染物和特殊有机污染物的去除以及系统基质中微生物的种群和活性等内容,并结合我国研究现状展望了该领域的研究前景。人工湿地系统微生物对污染物去除将成为人工湿地生态系统服务功能评价、人工湿地生态系统健康与稳定的诊断的重要组成部分。     

土壤渗滤对有机微污染物去除性能研究

采用土壤柱试验研究了土壤渗滤对再生水中有机微污染物的去除性能。结果表明,土壤柱对再生水中的DOC、UV₂₅₄、总氮和总磷有较好的去除效果,并具有较高的抗冲击负荷的能力;土壤表层10 cm厚度对DOC的去除起主要作用;UV₂₅₄和AOX在土壤表层10 cm厚度降解效果不明显,随着深度增加去除率逐渐升高;液相色谱有机碳探测(LC-OCD)检测结果表明,土壤柱对溶解性有机物质的去除主要体现在对多糖物质的降解上,其次是有机酸类,对腐殖质也有一定的去除作用。     

不同复合人工湿地对高污染河流有机污染物的去除

为了研究复合人工湿地对高污染河流污水中有机污染物的去除效果及规律,实验构建了不同水力负荷下的潜流+潜流、潜流+表面流、潜流+潜流+表面流、表面流+表面流等人工湿地单元组合成的5个复合人工湿地.连续运行一年以来,各复合人工湿地对BOD5、COD和SS的去除效果分别为91.9％ ～94.7％、69.3％ ～75.8％和92.3％ ～ 93.9％,相对于多级表流湿地,多级潜流湿地更利于有机污染物和悬浮物的去除;BOD5、COD和SS主要在各复合湿地的第一级湿地单元内得到去除;复合人工湿地对COD去除效果秋夏季两季好,春冬两季差;复合人工湿地能有效去除悬浮态BOD5和COD,出水中部分溶解态有机物难以有效降解.     

零价铁复合有机膨润土处理染料废水的研究

针对目前印染废水处理现状及膨润土在水处理中回收困难等问题,提出将零价铁复合到有机膨润土中制成零价铁复合有机膨润土(ZVI-OB),以达到高效吸附并降解污染物的目的。以染料废水(Orange II) 作为研究对象,考察了废水中染料的初始浓度、pH以及吸附时间对ZVI-OB去除染料效率的影响,并研究了吸附后降解过程中时间和pH对污染物降解的影响以及降解前后膨润土层结构的变化。研究结果表明,ZVI-OB相对于CTMAB改性的有机膨润土而言,其吸附量有所降低,但ZVI-OB在吸附污染物之后能有效降解有机物。ZVI-OB在饱和吸附Orange II后经催化氧化,总有机碳含量降低为原来的19%,可以重复利用。     

人工湿地去除污水厂尾水中的营养元素和雌激素

利用复合垂直流人工湿地对城镇污水厂尾水进行深度处理,研究了湿地系统对水中营养元素及微量雌激素的去除效果。结果表明:复合垂直流人工湿地对污水厂尾水具有良好的处理效果;水力负荷、填料种类、植物、季节等因素影响湿地处理效果。复合垂直流湿地系统对污染物的去除作用主要发生在下行池前1/6段,种植芦苇的沸石湿地系统处理效果最佳;在水力负荷为0.12 m~3·(m~2·d)~(-1)时,运行良好的复合垂直流湿地出水水质指标达到《城市污水再生利用景观环境用水水质》标准(GB/T 18921-2002)。     

土壤气相抽提技术去污规律及土层压力变化特征分析

土壤气相抽提(SVE)技术可有效去除包气带土壤中挥发性有机污染物(VOCs),是一种经济高效的土壤原位修复技术.对北京市某化工厂内进行SVE技术的现场应用,去除污染土壤中的VOCs,研究污染物的消减规律以及土层压力的变化特征.结果表明,抽出气体的污染物浓度随SVE的运行不断降低,群井抽气初期,VOCs浓度迅速下降,之后...     

持久性有机污染物的环境分布与生物危害

介绍了国内外持久性有机物的研究进展,分析了中国典型地区中的持久性有机污染物的分布情况,其中淮河中下游的PAHs含量较高,而大连湾检测出的DDTs和PCBs含量均高于其他地区。持久性有机污染物可以在动植物体内不断富集,据分析,有机污染物在鱼类的富集因子可高达1124．1,持久性有机污染物通过食物链的富集逐级放大,对全球生态构成潜在巨大的威胁。近年来,由于持久性有机污染物的影响,在世界各地出现了动物的死亡、甚至灭绝的现象,而且有机污染物在人体内的蓄积,会对人体产生极大的的影响。最后,就当前存在的问题,提出了对策与建议,指出了该领域的发展方向。     

环境水体微污染有机物及其去除技术研究进展

水体有机污染物因其生物毒性对人体健康和生态环境造成了严重的危害。随着环保技术的发展,高浓度有机污染物已得到很好的去除。检测水平的不断提高使微量有机污染物日益受到广泛关注。为了深入地研究微污染有机物及其去除技术,对微污染有机物的种类、性质和危害进行了详细阐述,并综述了国内外生物法、膜处理技术、高级氧化技术、吸附技术对微污染有机物的去除效果,总结了各种技术的优缺点。     

纳滤生产再生水示范工程运行效果分析

纳滤(NF)作为一种深度处理工艺,在再生水生产领域具有广阔应用前景,但目前其在生活污水深度处理方面的工程应用不多。为此,对北京市某再生水厂的NF示范工程进行了跟踪研究,评价了NF工艺对各水质指标的去除效果及稳定性。结果表明:该示范工程的NF工艺可以有效地去除化学需氧量(COD)、总磷(TP)、重金属等指标,使出水的这些指标达到《地表水环境质量标准》中Ⅲ类水的相关标准;但对TN的截留能力较差,截留率不足15%,为出水达标的限制因子;NF工艺对大部分微量有机污染物的截留率在70%以上,但对于双酚A和卡马西平截留率较低,分别只有64.1%和53.4%,截留率与目标物分子质量大小及带电情况有关。细菌发光实验结果表明,NF工艺可以保障出水达到无毒状态。     

Chloroaromatic pollutants in mussels incubated in two finnish watercourses polluted by industry

Concentrations of different chlorinated compounds were measured in mussels incubated in two polluted watercourses, a river (the River Kymijoki) and a lake (Lake Vanaja) for four weeks in summer 1995. The sum concentrations of polychlorinated phenols (PCP) and biphenyls (PCB) were both about 1 μg/g lipid weight (lw) in Lake Vanaja mussels, while in the River Kymijoki mussels PCPs were non-detectable and PCBs were measured 120 ng/g lIw. The concentrations of toxic polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners ranged between <17 and 370 pg/g Iw in Lake Vanaja mussels and between <38 and 11,000 pg/g lw in the River Kymijoki mussels. Polychlorinated diphenyl ethers (PCDE) were detected in the mussels incubated in the River Kymijoki (0.4–1.1 ng/g Iw), but not in those incubated in Lake Vanaja. Polychlorinated phenoxyanisoles (PCPA) were measured 33 ng/g lw and polychlorinated phenoxyphenols (PCPP) 300 ng/g lw in the mussels incubated in the River Kymijoki. PCPAs were also detected in reference samples, which were sediment and pike from the River Kymijoki and Baltic salmon, seal and white-tailed sea eagle.     

Evaluation of trichloroethene recovery processes in heterogeneous aquifer cells flushed with biodegradable surfactants

The ability of two biodegradable surfactants, polyoxyethylene (20) sorbitan monooleate (Tween 80) and sodium dihexyl sulfosuccinate (Aerosol MA), to recover a representative dense non-aqueous-phase liquid (DNAPL), trichloroethene (TCE), from heterogeneous porous media was evaluated through a combination of batch and aquifer cell experiments. An aqueous solution containing 3.3% Aerosol MA, 8% 2-propanol and 6 g/l CaCl(2) yielded a weight solubilization ratio (WSR) of 1.21 g TCE/g surfactant, with a corresponding liquid-liquid interfacial tension (IFT) of 0.19 dyn/cm. Flushing of aquifer cells containing a TCE-DNAPL source zone with approximately two pore volumes of the AMA formulation resulted in substantial (>30%) mobilization of TCE-DNAPL. However, a TCE mass recovery of 81% was achieved when the aqueous-phase flow rate was sufficient to displace the mobile TCE-DNAPL toward the effluent well. Aqueous solutions of Tween 80 exhibited a greater capacity to solubilize TCE (WSR=1.74 g TCE/g surfactant) and exerted markedly less reduction in IFT (10.4 dyn/cm). These data contradict an accepted empirical correlation used to estimate IFT values from solubilization capacity, and indicate a unique capacity of T80 to form concentrated TCE emulsions. Flushing of aquifer cells with less than 2.5 pore volumes of a 4% T80 solution achieved TCE mass recoveries ranging from 66 to 85%, with only slight TCE-DNAPL mobilization (<5%) occurring when the total trapping number exceeded 2 x 10(-5). These findings demonstrate the ability of Tween 80 and Aerosol MA solutions to efficiently recover TCE from a heterogeneous DNAPL source zone, and the utility of the total trapping number as a design parameter for a priori prediction of DNAPL mobilization and bank angle formation when flushing with low-IFT solutions. Given their potential to stimulate microbial reductive dechlorination at low concentrations, these surfactants are well-suited for remedial action plans that couple aggressive mass removal followed by enhanced bioremediation to treat chlorinated solvent source zones.     

Book review

The Pesticide Manual ‐ A World Compendium, 8th Edition, C.R. Worthing, Editor and S.B. Walker, Assistant Editor, British Crop Protection Council, BCPC Publications Sales, Bear Farm, Binfield, Bracknell, Berkshire RG12 5QE, England. 1987, 1100 pp., UK £50; Overseas £56. ISBN 0–948404–01–9.     

The variation of street air levels of PAH and other mutagenic PAC in relation to regulations of traffic emissions and the impact of atmospheric processes

The occurrence of particle associated PAH and other mutagenic PAC was determined in 1996 in the street air of Copenhagen. In addition, particle extracts were tested for mutagenicity. The measurements were compared with previous measurements in 1992/1993. The levels had decreased in this period. The decrease was caused by an implementation of light diesel fuels for buses and the exchange of older petrol-driven passenger cars with catalystequipped new ones. About 65% of the reduction was caused by the application of the light diesel fuels. Under special conditions, chemical processes in the atmosphere produced many more mutagens than the direct emissions. The concentrations of S-PAC and N-PAC were 10 times lower than those of PAH, while the levels of oxy-PAH were in the same order of magnitude as those of PAH. Benzanthrone, an oxy-PAH, is proposed to be formed in the atmosphere in addition to direct emissions. Benzo(a)pyrene, often applied as an air quality criteria indicator, was photochemically degraded in the atmosphere. A strong increase in the mutagenic activities was observed to coincide with a depletion of benzo(a)pyrene.     

Organochlorine compounds in a three-step terrestrial food chain

The concentrations of 15 organochlorine chemicals (PCBs and pesticides) were studied in a Central European oak wood food chain system: Great tit (Parus major), caterpillars (Tortrix viridana, Operophtera brumata, Erannis defoliaria), and oak-leaves (Quercus robur). Juvenile tits receive organochlorines from the mother via egg transfer and, eventually to a greater extent, from the caterpillar food source during nestling period. The concentrations of PCB 153 (2,2′,4,4′,5,5′-hexachlorobiphenyl, the most abundant in this study) was found in leaf material at ca. 1 ng/g, in caterpillars 10 ng/g, and in bird eggs 170 ng/g on an average and on a dry mass basis.     

The chemical stability of formulations of some hydrolyzable insecticides in aqueous mixtures with hydrolysis catalysts

Abstract

The active ingredients in commercial formulations of malathion, oxamyl, carbaryl, diazinon, and chlorpyrifos diluted to “spray tank”; concentrations with buffered distilled or natural water of pH 4–9 were stable for at least 24 hr. Formulations of trichlorfon were not stable at pH 7 or above but disappearance rates were slower than for the pure chemical in homogeneous solution. Cupric ion was observed to be an effective catalyst for the hydrolysis of a variety of pure organophosphorus insecticides but did not catalyze hydrolysis of the active ingredients of the formulations examined. Increasing the dilution of the formulation increased the susceptibility of malathion, oxamyl, and carbaryl to hydrolysis.     

Observations on the influence of water and soil pH on the persistence of insecticides

Abstract

The pH‐disappearance rate profiles were determined at ca. 25°C for 24 insecticides at 4 or 5 pH values over the range 4.5 to 8.0 in sterile phosphate buffers prepared in water‐ethanol (99: 1 v/v). Half‐lives measured at pH 8 were generally smaller than at lower pH values. Changes in half lives between pH 8.0 and 4.5 were largest (>1000x) for the aryl carbamates, carbofuran and carbaryl, the oxime carbamate, oxamyl, and the organophosphorus insecticide, trichlorfon. In contrast, half lives of phorate, terbufos, heptachlor, fensulfothion and aldicarb were affected only slightly by pH changes. Under the experimental conditions described half lives at pH8 varied from 1–2 days for trichlorfon and oxamyl to >1 year for fensulfothion and cyper‐methrin. Insecticide persistence on alumina (acid, neutral and basic), mineral soils amended with aluminum sulfate or calcium hydroxide to different pH values and four natural soils of different pH was examined. No correlation was observed between the measured pH of these solids and the rate of disappearance of selected insecticides applied to them. These observations demonstrate the difficulty of extrapolating the pH dependent disappearance behaviour observed in homogeneous solution to partially solid heterogeneous systems such as soil.     

Teratological effects of pesticides in vertebrates: a review

Abstract

In the last decades, the use and misuse of pesticides in the agriculture have increased, having a severe impact on ecosystems and their fauna. Although the various effects of pesticides on biodiversity have been already documented in several studies, to our knowledge no consistent overview of the impact of pesticides in vertebrates, both terrestrial and aquatic, is available. In this review, we try to present a concise compilation of the teratogenic effects of pesticides on the different classes of vertebrates – mammals, birds, reptiles, amphibians and fish.     

Radionuclides in pinon pine (Pinus edulis) nuts from los alamos national laboratory lands and the dose from consumption

Abstract

One of the dominant tree species growing within and around the eastern portion of Los Alamos National Laboratory (LANL), Los Alamos, NM, lands is the pinon pine (Pinus edulis). Pinon pine is used for firewood, fence posts, and building materials and is a source of nuts for food—the seeds are consumed by a wide variety of animals and are also gathered by people in the area and eaten raw or roasted. This study investigated the (1) concentration of ³H, ¹³⁷Cs, ⁹⁰Sr, ^totU, ²³⁸Pu, ^{239, 240}Pu, and²⁴¹ Am in soils (0‐ to 12‐in. [31 cm] depth underneath the tree), pinon pine shoots (PPS), and pinon pine nuts (PPN) collected from LANL lands and regional background (BG) locations, (2) committed effective dose equivalent (CEDE) from the ingestion of nuts, and (3) soil to PPS to PPN concentration ratios (CRs). Most radionuclides, with the exception of ³H in soils, were not significantly higher (p < 0.10) in soils, PPS, and PPN collected from LANL as compared to BG locations, and concentrations of most radionuclides in PPN from LANL have decreased over time. The maximum net CEDE (the CEDE plus two sigma minus BG) at the most conservative ingestion rate (10 lb [4.5 kg]) was 0.0018 mrem (0.018 μSv); this is far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem (1000 μSv). Soil‐to‐nut CRs for most radionuclides were within the range of default values in the literature for common fruits and vegetables.     

Degradation and sorption of imidacloprid in dissimilar surface and subsurface soils

Degradation and sorption/desorption are important processes affecting the leaching of pesticides through soil. This research characterized the degradation and sorption of imidacloprid (1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine) in Drummer (silty clay loam) and Exeter (sandy loam) surface soils and their corresponding subsurface soils using sequential extraction methods over 400 days. By the end of the incubation, approximately 55% of imidacloprid applied at a rate of 1.0 mg kg^?1 degraded in the Exeter sandy loam surface and subsurface soils, compared to 40% of applied imidacloprid within 300 days in Drummer surface and subsurface soils. At the 0.1 mg kg^?1 application rate, dissipation was slower for all four soils. Water-extractable imidacloprid in Exeter surface soil decreased from 98% of applied at day 1 to > 70% of the imidacloprid remaining after 400 d, as compared to 55% in the Drummer surface soil at day 1 and 12% at day 400. These data suggest that imidacloprid was bioavailable to degrading soil microorganisms and sorption/desorption was not the limiting factor for biodegradation. In subsurface soils > 40% of ¹⁴C-benzoic acid was mineralized over 21 days, demonstrating an active microbial community. In contrast, cumulative ¹⁴CO₂ was less than 1.5% of applied ¹⁴C-imidacloprid in all soils over 400 d. Qualitative differences in the microbial communities appear to limit the degradation of imidacloprid in the subsurface soils.