生化法处理煤气废水

采用Ａ／Ｏ工艺处理煤气废水的研究结果表明,该工艺能同时去除煤气废水中的有机物和氨氮,在试验确定的条件下,该工艺对煤气废水中的ＣＯＤｃｒ去除率达９１．０％,ＢＯＤ５去除率达９９．１％,ＮＨ３－Ｎ去除率达９９．２％,ＴＮ去除率达９４．７％。     

土壤含水层处理的试验研究

研究了好氧,缺氧,厌氧三种状态下土壤含水层处理工艺对北京高碑店污水处理厂二级出水中有机物的去除效果,ＢＯＤ５去除率大于９０５,ＣＯＤ,ＤＯＣ,ＵＶ－２５４去除率１２％－２５％之间,厌氧状态下,通过共代谢作用,可去除约５５％的ＡＯＸ;好氧状态下,出水ＮＨ３－Ｎ浓度低于０．５display status     

驯化活性污泥处理明胶有机废水的实验

利用驯化活性污泥对组分复杂的明胶有机废水进行有机物降解实验。结果表明,明胶废水的ＢＯＤ５／ＣＯＤｃｒ比值为０．４４－０．４６,ＣＯＤｃｒ进水浓度在１０００－１２００ｍｇ／Ｌ人,ＣＯＤｃｒ和ＢＯＤ５去除率分别达８１％－８３％和８６％－９１％。     

吹脱法去除渗滤液中氨的动力学及机理

不同条件下渗滤液中ＮＨ３－Ｎ吹脱效果及其去除动力和机理的研究表明,在ＰＨ＝１１,Ｔ＝２２．５℃,及供气量为１０Ｌ／ｍｉｎ的条件下,经５ｈ的曝气吹脱,可获得６８．７％－８２．５％的ＮＨ４＾＋－Ｎ去除率。     

动力学光度法测定环境水样中痕量钒（V）

在柠檬酸介质中，Ｖ＾５＋对ＫＢｒＯ３氧化甲基紫的反应有催化作用，研究了其催化动力学条件，由此建立了痕量Ｖ＾５＋的测定方法。方法检出限为１．８μｇ／Ｌ，线性范围为０－０．３２０μｇ／２５ｍｌ，对水环境样品进行精密度试验和加标回收实验。相对偏差为７．２％，加标回收率为９０．６－９７．５％。     

重氮化偶合反应测定亚硝酸盐方法的改进

用Ｈ酸代替α－萘胺或盐酸萘乙二胺作为重氮化合物的偶联试剂测定水中亚硝酸盐，亚硝酸盐在０．０２５￣１．０μｇ／ｍＬ范围内与吸光值呈线性关系。方法的精密度ＣＶ％小于５，样品加标回收率范围在９６．５％￣１０５％之间，结果令人满意。     

絮凝—酸化法预处理腈纶纺丝生产废水的实验研究

研究采用絮凝－酸化法对腈纶纺丝废水进行预处理,考察了絮凝剂的选用及多种絮凝实验条件对实验结果的影响。结果表明,以ＰＦＳ作絮凝剂,絮凝ｐＨ６．０,ＰＦＳ 投加量为０．３ｍｌ,ＰＡＭ投加量为０．４ｍｌ时的ＣＯＤ,ＢＯＤ５和ＮＨ３－Ｎ及ＣＮ＾－去除率分别为３０％,３１％,８％及３２％。     

酸性分散染料废水的治理及综合利用研究

利用硫酸含量达１５％－４０％的酸性分散染料废水和废铁作用制得聚合硫酸铁,并用其作净水剂处理印染废水。结果表明,每ｔ酸性废水可生产１．０５ｔ浓度１６０ｇ／ＬＦｅ＾３＋的取合硫酸铁溶液,出水的酸含量降低了８３．５％。用所制得的聚合硫酸铁处理印染废水,ＣＯＤ去除率可达７０．４％－９５．４％,色度去除率可达６５．７％＿９０．５％,具有较好处理效果。     

多元线性回归分光光度法同时测定污水中的苯酚,苯胺

苯酚、苯胺与４－ＡＡＰ络合后所形成的吸收光谱出现严重重桑。采用多元线性，建立了计算分光光度法可测定污水苯酚、苯胺含量。其加标回收率分别在９５－１０５％，９８－１０３．３％之间，方法较好地解决了采用分光光度法测定污水中苯酚、苯胺时的相互干扰。     

气相色谱-质谱法测定水中挥发性有机物的测量不确定度评定

根据测量不确定度评定与表示理论，采用气相色谱一质谱法测定水中挥发性有机物。以氯乙烯为例，通过计算和评定，得出当氯乙烯的测量结果为4．99μg／L时，取包含因子k=2（约95％置信概率），扩展不确定度U=0．96μg／L。该不确定度评定方法在实际工作中具有较强的实用价值。     

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.     

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.     

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.     

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.     

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.     

Patterns of volatile metabolites and nonvolatile trichothecenes produced by isolates of <Emphasis Type="Italic">Stachybotrys,Fusarium, Trichoderma,Trichothecium</Emphasis> and <Emphasis Type="Italic">Memnoniella</Emphasis>

We reported previously that trichodiene, a volatile trichothecene derivative, was produced by a Stachybotrys isolate, also known to produce highly cytotoxic, non-volatile, macrocyclic trichothecenes (satrotoxins). We investigated the relationship between the production of trichodiene and various non-volatile trichothecenes for several molds. Volatile metabolites were concentrated by adsorption on Tenax TA and analyzed by GC/MS, while non-volatile metabolites were separated by HPLC, derivatized and analyzed by GC/MS. Stachybotrys chartarum isolates producing macrocyclic trichothecenes secreted significantly larger amounts of trichodiene and other sesquiterpenes than isolates which only produced simple trichothecenes. The amounts of secreted trichodiene were relatively small in all cases. With the exception of Memnoniella, which excreted small amounts of sesquiterpenes, the other isolates produced varying amounts of sesquiterpenes, including trichodiene, as well as simple tricothecenes, no detectable trichodiene, but large amounts of griseofulvin derivatives. In Stachybotrys there is apparently a correlation between trichodiene and macrocyclic trichothecene production. In the remaining isolates, there was no simple relationship between trichodiene and non-volatile trichothecene synthesis. Trichodiene is produced in larger amounts by Stachybotrys isolates, which also produce satratoxins, but it will be difficult to utilize this metabolite to detect toxic isolates in buildings due to the relatively small amounts excreted.     

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.     

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.     

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.     

Knowledge transfer initiative between molecular biologists and environmental researchers and regulators

A Natural Environment Research Council (NERC) funded Knowledge Transfer (KT) workshop was held in the United Kingdom (UK) to identify the needs and opportunities in the application of molecular biology and ‘omics’ techniques to environmental monitoring and risk assessment. Attendees highlighted a lack of effective communication between end-users and researchers as well as difficulties with data interpretation as reasons behind the slow uptake of molecular biology and omics techniques. A number of promising areas in which new techniques could be implemented at a practical level in the very near future were identified, thereby raising the profile of these recent technologies and providing vital proof of concept work. Molecular taxonomy, bacterial source tracking and pre-screening of chemicals for potential toxicities were all viewed as areas in which omics and molecular techniques could have immediate value, with the aim of reducing cost, increasing efficiency and providing more comprehensive data of improved quality.