祁连山北麓降水酸碱度和电导率特点及其与气候因素的关系

为了解祁连山北麓降水酸碱度和电导率(EC)特征及其与气候因素的关系,对祁连山北麓永昌县2013年4月至2014年7月的降水样品的pH和EC进行了分析,并选取研究区典型的沙尘事件来分析探讨pH和EC在沙尘事件发生前后的变化情况。结果表明:祁连山北麓降水的pH为6.84~8.34,平均值为7.47,EC平均值为207.59μS/cm;研究区四季降水的EC表现为秋季冬季夏季春季,pH表现为秋季夏季春季冬季;pH与风速呈显著的正相关关系,EC与降水量和气温均呈显著的负相关关系;在沙尘事件发生前,pH会出现升高趋势,而EC表现出降低趋势。     

杭州市大气降雨化学组成特征及来源分析

研究了2006-2008年杭州市大气降雨的化学组成及其来源,并与国内外的相关研究结果进行了比较.结果表明,总体来说,杭州市各月的降雨量相对均衡,月均降雨量为7.1～25.3 mm;降雨pH为3.99～5.64,雨量加权平均pH为4.50;降雨电导率为1.30～8.55 mS/m,雨量加权平均值为3.73 mS/m,降雨电导率与雨量、pH均呈负相关;夏季降雨中的水溶性离子平均浓度较低,雨量加权平均pH较高,而其他季节降雨中的水溶性离子平均浓度较高,雨量加权平均pH较低;其中SO2-4和NO-3是降雨中的主要水溶性阴离子,NH+4和Ca2+是降雨中的主要水溶性阳离子;SO2-4/NO-3(当量浓度比)为2.87,低于国内其他城市,降雨类型为硫酸型,但硝酸在降雨酸性中起的作用有增大趋势;降雨中水溶性阳离子总当量浓度/水溶性阴离子总当量浓度为1.11,低于国内外大部分城市;NH+4、Ca2+当量浓度之和与SO2-4、NO-3当量浓度之和之比为0.89,也低于国内外大部分城市,NH+4和Ca2+是主要的酸性中和物质;总体来说,杭州市降雨中各水溶性离子间的相关性均较好,但H+浓度与大部分离子的相关性不明显;杭州降雨中的化学组分主要来源于工业源和地壳源,此外部分来源于海盐粒子.     

天津市臭氧污染特征及来源解析研究

使用天津市2013—2017年的连续臭氧观测数据,分析了天津市的臭氧污染特征,并使用基于排放清单处理模型(SMOKE)/中尺度气象模型(WRF)/多尺度空气质量模型(CAMx)的臭氧来源解析技术对天津市不同季节的臭氧来源情况进行研究。结果表明,天津市臭氧污染整体波动变化,年均浓度总体呈现先下跌后上升的趋势;天津市臭氧夏季浓度较高,春季、秋季浓度较低,冬季浓度最低。天津市臭氧污染区域性特征明显,区域输送贡献远大于本地贡献,本地臭氧来源贡献率仅占8%～20%。河北省、山东省、内蒙古自治区等地区污染物排放对天津市臭氧污染有较大贡献。天津市本地源对臭氧的贡献季节差异较大,其中工业源贡献较大,其在春季、秋季对臭氧贡献率分别为49%、43%。夏季天然源、工业源、交通源与电厂源对臭氧贡献率较为接近,均在20%～30%;冬季其他源(包括生物质燃烧源、居民燃烧源等)对臭氧贡献率最大,为54%。未来应根据臭氧污染来源的地域特征和季节特征采取不同臭氧污染防治策略。     

宝鸡市大气PM_(10)中水溶性物质的组成及特征研究

2008年冬、春季在宝鸡市4个不同功能区采集PM10样品,探讨了PM10中水溶性物质的化学组成、时空分布特征以及来源。结果表明,冬、春季PM10的平均质量浓度分别为(402±100)、(410±160)μg/m3,无明显季节差异,冬季以交通干道区的PM10浓度为最高,而春季则以商贸区的PM10浓度为最高;冬、春季PM10中水溶性有机碳(WSOC)浓度最高值均出现在商贸区,最低值则分别出现在背景点和交通干道区,水溶性无机碳(WSIC)浓度最高值分别出现在交通干道区和商贸区,最低值均出现在背景点;冬、春季PM10中所含大多数无机离子浓度不存在显著空间差异,但不同功能区PM10中无机离子所占质量分数差异较明显;冬、春季PM10中的水溶性物质质量浓度分别为207、151μg/m3,在PM10中所占质量分数分别为51%和40%,其中,冬、春季水溶性物质浓度最高的分别为居民区和商贸区;冬季PM10中WSOC浓度与SO24-、NO3-浓度有较好的相关性,说明冬季PM10中WSOC的主要组分为二次有机气溶胶,而春季PM10中WSOC浓度与SO42-、NO3-浓度的相关性相对较差,这是由于一次有机气溶胶对WSOC的贡献率较冬季显著增大;宝鸡市与北京市大气PM10浓度、PM10中的SO42-、NO3-、NH4+浓度最为接近;广州市大气PM10中的SO42-所占质量分数(14%)要高于北方城市(宝鸡市和北京市均为9%)。     

连云港酸雨变化特征及其影响因子分析

利用连云港酸雨观测资料和颗粒物浓度数据,分析了2008—2016年该地区酸雨的变化特征,同时讨论了酸雨发生前污染物浓度及其源地分布特点。结果表明:(1)统计时段内,连云港南、北部年均酸雨日数分别为33.2、21.3d;酸雨的年均pH分别为4.35和4.46,均达到强酸雨等级;8—9月酸雨日数最多,1月最少,但冬季酸雨频率较高。(2)连云港南、北部酸雨发生前平均连续无降水日数分别为2.8、4.0d,且连续性降水的酸雨酸性并不会因为前一天有降水而明显减弱。(3)酸雨开始前,南部地区大气中SO2平均质量浓度达27.6μg/m3,为北部地区的两倍。基于拉格朗日混合单粒子轨迹(HYSPLIT)模式的后向轨迹聚类分析表明,西北和偏南两种路径在连云港南、北两地强酸雨发生前气团轨迹中占比较大,均达60%以上,其源地分别对应华北和长三角两个工业集中、SO2等污染物排放高的地区。     

太原市降水化学特征及来源分析

本研究采集了2012年3—11月间35场太原降水样品,探讨了pH值、电导率和水溶性化学组成特征。结果表明,降水pH加权平均值为5.27;电导率平均值为98.8μS/cm,表明大气污染显著;SO2-4(471.8μeq/L)、NO-3(93.6μeq/L)、Ca2+(477.4μeq/L)和NH+4(133.4μeq/L)是太原降水的主导离子,4种离子占总离子浓度的85%。SO2-4/NO-3当量浓度比为4.38,比太原市1986年的比值(19.02)下降了77%。太原降水的酸性仍以SO2-4主导,但NO-3比例大幅上升。降水离子相关性分析和气团后向轨迹表明太原市大气污染物主要来自自身排污企业(热电厂、钢铁厂等)污染物的扩散以及省内焦化企业污染物的输送等小尺度区域内。太原市硫的湿沉降量为1.93 t/(km2·a);氮湿沉降量为1.54 t/(km2·a),其中铵态氮和硝态氮分别为1.28 t/(km2·a)和0.26 t/(km2·a);钙为5.87 t/(km2·a)。     

广州地区酸雨状况及其影响因素探讨

对广州地区降水酸度、酸雨频率的年际变化进行了研究,发现近十几年来广州地区的酸雨污染有所减缓,但2001-2003年有恶化的趋势.为探究原因,追溯主要酸雨污染物来源,并对各酸雨污染物进行综合评价,结论表明,广州地区的大气环境已从过去的以SO2为主的煤烟型污染转变为以NOX为主的氧化型污染.还讨论了广州地区气象条件对酸雨形成的影响.     

安顺市酸雨形成特点

前 言 酸雨是大气污染物的一种特殊形式。据全国酸雨普查,西南地区是我国的强酸雨区。1982年至1985年贵州省酸雨监测结果表明:贵州省中部的贵阳市、遵义市、安顺市、都匀市是我省酸雨污染最为严重的核心区域。 安顺市酸雨监测工作始于一九八二年。在冬、春、夏、秋四季的2、5、8、11月份,采集每次降水样品,测其pH值,并分析了部分样品中 SO_4~(2-)、NO_3~-、NH_4~+、Ca~(2+)等离子的含量。1983年10月本站参予了贵州     

天津市灰霾评价等级指标体系研究

根据天津市2003—2007年灰霾日的污染物浓度和气象资料,应用主成分分析方法得出影响灰霾的5个主要因子(SO2、相对湿度、总云量、PM10和风速)。对相对湿度、总云量和风速3个气象因子的历史资料进行频数统计分析,并建立了各气象因子的等级划分标准。利用灰色聚类法构建了天津市灰霾评价的等级指标体系,灰霾等级划分结果表明,天津市轻度灰霾和重度灰霾出现天数相对较少,均以中度灰霾为主;轻度灰霾大多出现在春季和夏季;重度灰霾主要出现在冬季,春季出现的比例最小;综合评价分析,冬季灰霾污染程度最为严重。     

天津市大气能见度与空气污染物关系分析及控制措施

利用天津市1990—2004年大气能见度观测资料及天津市2002—2004年空气污染物监测数据,统计分析了天津市大气能见度变化特征及其与空气污染物的关系。结果表明,天津市20世纪90年代大气能见度处于波动下降趋势,2000—2003年大气能见度整体水平有所改善,到2004年空气质量迅速提高。统计数据说明,在非采暖季的春季,天津市大气能见度的下降与PM10浓度有较大相关性;在夏季,与相对湿度有较大相关性;在采暖季(冬季),与SO2和NOX等空气污染物浓度有密切关系。同时,提出改善城市大气能见度的4个措施:(1)制定长期的大气能见度控制策略;(2)合理改善能源结构;(3)加强城市裸露土地的治理;(4)城市交通采用清洁能源。     

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.     

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.     

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.     

Sorption and predicted mobility of herbicides in Baltic soils

This study was undertaken to determine sorption coefficients of eight herbicides (alachlor, amitrole, atrazine, simazine, dicamba, imazamox, imazethapyr, and pendimethalin) to seven agricultural soils from sites throughout Lithuania. The measured sorption coefficients were used to predict the susceptibility of these herbicides to leach to groundwater. Soil-water partitioning coefficients were measured in batch equilibrium studies using radiolabeled herbicides. In most soils, sorption followed the general trend pendimethalin > alachlor > atrazine～ amitrole～ simazine > imazethapyr > imazamox > dicamba, consistent with the trends in hydrophobicity (log K_ow) except in the case of amitrole. For several herbicides, sorption coefficients and calculated retardation factors were lowest (predicted to be most susceptible to leaching) in a soil of intermediate organic carbon content and sand content. Calculated herbicide retardation factors were high for soils with high organic carbon contents. Estimated leaching times under saturated conditions, assuming no herbicide degradation and no preferential water flow, were more strongly affected by soil textural effects on predicted water flow than by herbicide sorption effects. All herbicides were predicted to be slowest to leach in soils with high clay and low sand contents, and fastest to leach in soils with high sand content and low organic matter content. Herbicide management is important to the continued increase in agricultural production and profitability in the Baltic region, and these results will be useful in identifying critical areas requiring improved management practices to reduce water contamination by pesticides.