城市生活垃圾问题研究的系统动力学方法

利用被称为战略与策略实验室的系统动力学方法,建立了城市生活垃圾问题的系统动力学研究模型;以北京市为实例,探讨了垃圾排放及污染随人口和经济发展的变化,以及污染和占地损失、绿色GDP核算、居民家庭、企事业单位生活垃圾与建筑垃圾组合收费方案等问题.     

基于集装化外运与综合型处理的上海城市生活垃圾管理对策

分析了上海市区生活垃圾收运处理现状与问题,借鉴国外特大城市生活垃圾收运处理管理经验和教训,提出了将现有垃圾水运系统升级改造为集装化水陆联运系统、将现有老港废弃物处置场扩建为生活垃圾分类、生化处理、焚烧发电、填埋等多种技术有机组合的综合型处理基地的方案,为改善上海市生活垃圾收运与处理处置系统提出可行的对策建议.     

原位回灌对垃圾填埋场稳定化进程影响的实验研究

针对填埋法处理城市生活垃圾造成的土地占用和水资源污染等系列环境问题,通过在实验室搭建的模拟城市生活垃圾填埋场实验台,系统研究了淋滤介质、淋滤量和淋滤频率等条件对生活垃圾填埋场稳定化进程的影响。结果表明:采用垃圾渗滤液原液淋滤、淋滤频率为3次/d、淋滤总量为10L时,垃圾填埋场初期稳定化进程最快;在此条件下,垃圾渗滤液中污染物COD、氨氮和TP出现负增长对应的时间分别为17、29、18d。研究结果对进一步开展垃圾渗滤液深度处理和工程应用等相关研究具有重要的指导意义。     

生活垃圾与煤混合燃烧特性及动力学分析

利用热重分析仪对生活垃圾与煤混合试样的燃烧特性及热反应动力学进行了实验研究,考察了不同配比混合试样的着火温度、燃尽温度、最大燃烧速率及最大燃烧速率温度等燃烧特征参数,并用Coats-Redfern积分法对其进行了燃烧动力学分析,确定了燃烧动力学方程,求出了反应活化能Ea及指前因子A。实验结果表明:生活垃圾与煤混合燃烧时均保持各自的燃烧特性;混合燃料中随着生活垃圾掺量的增加,热重曲线向低温区转移,燃尽点逐渐降低,综合燃烧特性指数明显增大,生活垃圾能改善煤的燃烧性能;生活垃圾及其与煤混合燃烧出现两个燃烧阶段,分别遵循二级和一级反应机理,煤燃烧只出现一个燃烧阶段,遵循一级反应机理;混合燃料燃烧反应活化能Ea与指前因子A存在动力学补偿效应。     

生活垃圾填埋场对地下水污染的风险评价——以北京北天堂垃圾填埋场为例

以国外生活垃圾填埋场对地下水污染的风险评价方法为基础,建立了综合考虑含水层脆弱性及生活垃圾填埋场自身性质的地下水污染风险评价方法,并以北京北天堂垃圾填埋场为例.评价了当地4个生活垃圾填埋场对地下水污染的风险级别.结果表明,生活垃圾填埋场对地下水污染的风险取决于场地规模、防护情况等自身相关参数以及场地所处位置的含水层脆弱...     

三峡库区垃圾污染现状及治理技术

如何搞好三峡库区的生态环境保护已成为全世界关注的课题，介绍了库区生活垃圾污染现状，并根据库区生活垃圾的特性及当地的经济发展和自然条件，对三峡库区生活垃圾的综合治理进行了系统研究，建议三峡库区垃圾实行分类收集，系统地将城区生活垃圾的管理、收集、运输和处理等各个环节有机结合起来，逐步建立起高效完善的现代化城市生活垃圾管理体系。重点介绍了准好氧垃圾卫生填埋技术和CBS（Cental Bilolgical System）城市生活垃圾高效菌种堆肥技术，秭归、巴东等烧煤区生活垃圾含无机物成分较高，建议选用准好氧填埋技术；涪陵、开县、忠县等燃气区生活垃圾有机物成分较高，已具备一定的资源化价值，高效菌种CBS堆肥技术在燃气区具有广阔的前景。     

四川城市生活垃圾重金属污染状况及来源分析

四川省作为西南粮食生产大省,土壤重金属污染问题备受关注,生活垃圾处理处置可能带来的土壤污染风险急需探明。结合四川省五大经济区的发展格局和多样的地形条件,研究了成都、宜宾、南充、达州、西昌、马尔康城市夏冬两季生活垃圾的物理组成、重金属含量及垃圾主要组分受污染状况。结果表明,四川地区生活垃圾中厨余、包装纸、卫生纸、橡塑和灰土是主要组分,共占总量的78.25%~96.92%;四川地区垃圾中Cu(14.23~107.56 mg/kg)、Cd(0.07~0.63 mg/kg)、Zn(53.77~338.30 mg/kg)、Hg(0.01~0.41 mg/kg)和Cr(35.39~179.63 mg/kg)浓度较高,易造成土壤污染。以土壤环境质量农业用地标准为参照计算得出的重金属污染负荷指数表明:仅夏季宜宾生活垃圾处于Ⅰ级中度污染;四川地区夏冬季总体处于无污染水平,且夏季污染负荷指数略高。通过测定垃圾主要组分中重金属含量,发现厨余和灰土是成都夏季垃圾中Cd的主要来源,灰土是四川地区垃圾中Cu、Zn和Cr的主要来源之一,燃煤产生的灰土是西昌冬季垃圾中Hg的主要来源。     

论生活垃圾处理与污染防治技术

详细分析了国内外生活垃圾污染途径和处理方法，根据中国生活垃圾的现状和特点，就国内外现有不同处理方式，提出了较为町行的生恬垃圾卫生填埋和污染防治技术。     

高热值城市生活垃圾归类分流处置的能值分析

生活垃圾处理已成为限制城市化进程和城市经济发展的重大问题之一,采用垃圾归类分流处置方法可以有效地促进垃圾减量化和资源化的效果。以西安市典型高校校园生活垃圾为代表性高热值焚烧型城市生活垃圾,通过绘制能值系统图辨析卫生填埋-沼气发电、焚烧发电、生物质燃料混烧发电等3种垃圾处理系统的能值投入和产出过程。依据垃圾物理组成和热值数据分别计算了2种处理系统的能值产出率、环境负载率、能值投资率、可更新能源投入率和能值可持续指数等5项基本能值指标,并从能量利用的角度对3种生活垃圾处理方法的环境可持续性与经济竞争力进行了比较分析。能值分析结果表明,采用生活垃圾焚烧和生物质燃料混烧发电处理法在能量转化效率和环境影响方面具有显著优势,对高热值焚烧型生活垃圾采用"归类分流-集中焚烧处理"的方式有利于提高城市生活垃圾减量化处理的环境效益与经济收益。     

生活垃圾恶臭污染释放过程研究

在实验室模拟填埋条件下,考察了不同垃圾组分、含水率、温度、填埋高度和压实密度对生活垃圾恶臭释放的影响。结果表明:生活垃圾恶臭物质主要来源于厨余垃圾、果皮垃圾和生活垃圾;含水率越高,恶臭物质释放越多;温度越高,恶臭物质释放越多;适当增加填埋高度不仅可以减少填埋作业面积,还可减少恶臭物质释放;提高生活垃圾的压实密度,可在增大恶臭气体迁移阻力、减轻恶臭污染的同时,增强垃圾堆体的稳定性,一定程度上增加了填埋库容。     

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.     

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.     

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.     

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 and trace elements in fish collected upstream and downstream of Los Alamos national laboratory and the doses to humans from the consumption of muscle and bone

Abstract

The purpose of this study was to determine radionuclide and trace element concentrations in bottom‐feeding fish (catfish, carp, and suckers) collected from the confluences of some of the major canyons that cross Los Alamos National Laboratory (LANL) lands with the Rio Grande (RG) and the potential radiological doses from the ingestion of these fish. Samples of muscle and bone (and viscera in some cases) were analyzed for ³H, ⁹⁰Sr, ¹³⁷Cs, ^totU, ²³⁸Pu, ^239,240Pu, and ²⁴¹Am and Ag, As, Ba, Be, Cr, Cd, Cu, Hg, Ni, Pb, Sb, Se, and Tl. Most radionuclides, with the exception of ⁹⁰Sr, in the muscle plus bone portions of fish collected from LANL canyons/RG were not significantly (p<0.05) higher from fish collected upstream (San Ildefonso/background) of LANL. Strontium‐90 in fish muscle plus bone tissue significantly (p<0.05) increases in concentration starting from Los Alamos Canyon, the most upstream confluence (fish contained 3.4E‐02 pCi g^‐1 [126E‐02 Bq kg^‐1]), to Frijoles Canyon, the most downstream confluence (fish contained 14E‐02 pCi g^‐1 [518E‐02 Bq kg^‐1]). The differences in ⁹⁰Sr concentrations in fish collected downstream and upstream (background) of LANL, however, were very small. Based on the average concentrations (±2SD) of radionuclides in fish tissue from the four LANL confluences, the committed effective dose equivalent from the ingestion of 46 lb (21 kg) (maximum ingestion rate per person per year) of fish muscle plus bone, after the subtraction of background, was 0.1 ± 0.1 mrem y^‐1 (1.0 ± 1.0 μSv y^‐1), and was far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem y^‐1 (1000 μSv y^‐1). Of the trace elements that were found above the limits of detection (Ba, Cu, and Hg) in fish muscle collected from the confluences of canyons that cross LANL and the RG, none were in significantly higher (p<0.05) concentrations than in muscle of fish collected from background locations.     

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.     

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.     

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.