青藏高原淡水湖泊水化学组成特征及其演化

青藏高原淡水湖具有高生态价值和高脆弱性并存的特点.以海拔5 080 m±10 m的打加芒错湖水为研究对象,测试及分析了湖水化学组分,探讨了其主要离子来源、控制因子和湖泊水化学演化趋势.结果表明,湖水阳离子以Ca2+和Na+为主,阴离子以HCO3-为主,为HCO3-Ca型水;TDS为71.2～199.8 mg·L-1,矿化度低;受地表径流的稀释作用和富铝贫钙的地质背景约束湖区东南部水体的EC、Ca2+和HCO3-浓度均较低.湖水的Na+/(Na++Ca2+)为0.08～0.75,Cl-/(Cl-+HCO3-)为0.11～0.35,Ca/Na值为0.58,Mg/Ca值为0.12,HCO3/Na值为1.46,据Gibbs模型和元素化学计量分析表明,其化学组成主要受硅酸盐岩风化控制.湖区流域参与风化的矿物岩石包括斜长石(钙长石、钠长石)、钾长石、云母、石膏、盐岩等,但以斜长石风化为主,湖水的K/Na值平均为0.059,表明流域钾长石风化程度较低.湖水中方解石、白云石、石英、石膏等矿物饱和指数(SI)大于0,石盐的SI则小于0,揭示了青藏高原上淡水湖泊演变成咸水湖的变化趋势.     

基于SOA和O3生成潜势的杭州市PM2.5和O3协同控制

2019年3月1日～2019年5月31日期间采用Syntech Spectras GC955在线气相色谱仪对杭州市大气环境中挥发性有机物（VOCs）进行了在线连续监测,分析了VOCs体积分数的组成特征、 PM_2.5和O₃协同控制的优控VOCs物种和VOCs特征污染物比值.结果表明,烷烃是VOCs体积分数中最重要的组分,贡献了62.40%. C2～C6的烷烃、苯系物、乙烯和乙炔是VOCs关键物种.烯烃和芳香烃是OFP的主要贡献组分,贡献率分别为41.35%和37.50%.芳香烃是SOA的主要贡献者,贡献率超过90%.低碳的烷烃、低碳烯烃和苯系物是OFP的关键贡献物种,控制好甲苯、间/对-二甲苯和邻-二甲苯这3种苯系物,是O₃和PM_2.5协同控制的关键.采样点大气中VOCs除了受机动车尾气的影响外,溶剂使用等工业排放的影响也较为显著.     

Monitoring of environmental exposure to polycyclic aromatic hydrocarbons: a review

Polycyclic aromatic hydrocarbons (PAHs) are a large group of organic compounds with two or more fused aromatic rings. They have a relatively low solubility in water, but are highly lipophilic. Most of the PAHs with low vapour pressure in the air are adsorbed on particles. When dissolved in water or adsorbed on particulate matter, PAHs can undergo photodecomposition when exposed to ultraviolet light from solar radiation. In the atmosphere, PAHs can react with pollutants such as ozone, nitrogen oxides and sulfur dioxide, yielding diones, nitro- and dinitro-PAHs, and sulfonic acids, respectively. PAHs may also be degraded by some microorganisms in the soil. PAHs are widespread environmental contaminants resulting from incomplete combustion of organic materials. The occurrence is largely a result of anthropogenic emissions such as fossil fuel-burning, motor vehicle, waste incinerator, oil refining, coke and asphalt production, and aluminum production, etc. PAHs have received increased attention in recent years in air pollution studies because some of these compounds are highly carcinogenic or mutagenic. Eight PAHs (Car-PAHs) typically considered as possible carcinogens are: benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene (B(a)P), dibenzo(a,h)anthracene, indeno(1,2,3-cd)pyrene and benzo(g,h,i)perylene. In particular, benzo(a)pyrene has been identified as being highly carcinogenic. The US Environmental Protection Agency (EPA) has promulgated 16 unsubstituted PAHs (EPA-PAH) as priority pollutants. Thus, exposure assessments of PAHs in the developing world are important. The scope of this review will be to give an overview of PAH concentrations in various environmental samples and to discuss the advantages and limitations of applying these parameters in the assessment of environmental risks in ecosystems and human health. As it well known, there is an increasing trend to use the behavior of pollutants (i.e. bioaccumulation) as well as pollution-induced biological and biochemical effects on human organisms to evaluate or predict the impact of chemicals on ecosystems. Emphasis in this review will, therefore, be placed on the use of bioaccumulation and biomarker responses in air, soil, water and food, as monitoring tools for the assessment of the risks and hazards of PAH concentrations for the ecosystem, as well as on its limitations.     

Polycyclic aromatic hydrocarbons, black carbon, and molecular markers in soils of Switzerland

Polycyclic aromatic hydrocarbons (PAH) were analysed in 23 soil samples (0–10 cm layer) from the Swiss soil monitoring network (NABO) together with total organic carbon (TOC) and black carbon (BC) concentration, as well as some PAH source diagnostic ratios and molecular markers. The concentrations of the sum of 16 EPA priority PAHs ranged from 50 to 619 μg/kg dw. Concentrations increased from arable, permanent and pasture grassland, forest, to urban soils and were 21–89% lower than median numbers reported in the literature for similar Swiss and European soils. NABO soils contained BC in concentrations from 0.4 to 1.8 mg/g dw, except for two sites with markedly higher levels. These numbers corresponded to 1–6% of TOC and were comparable to the limited published BC data in soil and sediments obtained with comparable analytical methods. The various PAH ratios and molecular markers pointed to a domination of pyrogenically formed PAHs in Swiss soils. In concert, the gathered data suggest the following major findings: (1) gas phase PAHs (naphthalene to fluorene) were long-range transported, cold-condensated at higher altitudes, and approaching equilibrium with soil organic matter (OM); (2) (partially) particle-bound PAHs (phenanthrene to benzo[ghi]perylene) were mostly deposited regionally in urban areas, and not equilibrated with soil OM; (3) Diesel combustion appeared to be a major emission source of PAH and BC in urban areas; and (4) wood combustion might have contributed significantly to PAH burdens in some soils of remote/alpine (forest) sites.     

天津城区夏冬季典型污染过程中BTEX变化特征及其健康风险评估

利用GC955在线气相色谱仪分别于2019年7月和2020年1月在天津市区开展苯系物(BTEX,包括苯、甲苯、乙苯、间/对-二甲苯和邻-二甲苯)实时在线观测,对典型污染过程中BTEX的浓度水平、组成及演化机制进行了研究,并运用特征物种比值法对BTEX的来源进行了定性分析,最后运用US EPA的人体暴露分析评价方法对BTEX健康风险进行评估.结果表明,臭氧和霾污染过程中BTEX体积分数平均值分别为1.32×10^-9和4.83×10^-9,其中苯的体积分数占比最大,其次是甲苯、乙苯和二甲苯占比最小.2020年1月BTEX体积分数很大程度上受到西南方向短距离传输的影响,而在2019年7月BTEX浓度受到本地排放的影响.BTEX浓度水平在2019年7月受到温度和相对湿度的共同影响,而在2020年1月当温度较低时BTEX浓度对相对湿度的变化更敏感.天津市区BTEX在霾污染过程中受生物质燃烧/化石燃料燃烧/燃煤排放的影响较大,而在臭氧污染过程中除了受到燃烧排放源影响,交通源排放在很大程度上也有影响.臭氧污染和霾污染过程中BTEX的HI分别为0.072和0....     

Biodegradation and phytotoxicity assessment of phenanthrene by biosurfactant-producing Bacillus pumilus 1529 bacteria

ABSTRACT

Phenanthrene is a toxic and mutagenic pollutant that can cause severe environmental and human health issues. The bioremediation of these polyaromatic hydrocarbons (PAHs) is possible with a biosurfactant by enhancing hydrophobicity. In this study, the production of a biosurfactant by Bacillus pumilus 1529 and its effects on the phenanthrene biodegradation pathway were examined. Biosurfactant production was determined using hemolytic activity, emulsification index, and surface tension. For phenanthrene metabolite detection, samples at 0, 7, 14, and 21 incubation days were analysed by gas chromatography-mass (GC-mass) spectrometry. The results showed that Bacillus pumilus 1529 can reduce surface tension to 22.83?±?1.1?mN?m^?1. Furthermore, the GC-mass spectrometry analysis showed that 1-hydroxy-2-naphthoic acid, benzaldehyde, o-phthalic acid, and phenylacetic acid were notable phenanthrene metabolites produced during phenanthrene biodegradation. Biodegraded phenanthrene and its metabolites have a less toxic effect on the germination of safflower seeds than non-biodegraded phenanthrene. The IC50 of phenanthrene on seed germination after biodegradation was increased to approximately 113?mg?L^?1. In general, biodegradation aided by biosurfactant producing bacteria contributed to turning the toxic phenanthrene into less harmful metabolites with lower phytotoxicity effects, indicating that its application in the bioremediation of PAHs is promising.     

Environmental impact assessment (EIA): Equilibrium fugacity calculations and worst case approach

A mathematical model UNITRISK which can be used for screening purposes and risk ranking was set up to calculate relative risk values of single chemicals and mixtures of chemicals towards single or mixtures of organisms via contamination of air, water, soil and food dose. The concentration values are calculated by applying the fugacity concept or a dose must be defined. The dose-response is assumed to be linear versus concentration and degradative processes are not considered which is the worst case. The assumption that equilibria between the environmental phases exist is simplifying the model and is also representing the worst case. A mean risk factor is calculated which is 1 if the endpoint values (LC₅₀, LD₅₀, ADI, etc.) are exceeded for the investigated organisms and man.     

大气颗粒物中多环芳烃的监测

本文报导了大气颗粒物中多环芳烃的一种测定方法和结果。颗粒物预处理方法是:超声萃取,抽滤,减压蒸发浓缩,硅胶柱净化,再浓缩,定容溶解。用高效液相色谱法分离和鉴定。对西南石油学院5个功能区冬季大气颗粒物中的苯并(a)芘等9种多环芳烃的分布状况进行了实测,苯并(a)芘平均含量为26ng/m~3,为国外一些大城市冬季值的三倍,为国内一些大城市冬季污染值的二分之一。     

A 25-year record of polycyclic aromatic hydrocarbons in soils amended with sewage sludges

We studied polycyclic aromatic hydrocarbons (PAHs) in crop soils amended with 1000 tonnes dry weight of sewage sludges per 10,000 m² from 1974 to 1992, then after sludges addition from 1993 to 1999. The absence of variations of total PAHs levels of control soils, averaging at 123 μg/Kg, shows the absence of horizontal contamination. During sludges addition, the total PAHs levels in amended soils increased from 232 to 402 μg/Kg. Seven years after sludges addition, it decreased to 275 μg/Kg, which is still more than twice –the levels of control soils. This finding shows that sludges PAHs are preserved in crop soils for long periods of time, on a human scale.     

Preliminary evidence for the metabolism of benzo(a) pyrene by Plantago lanceolata

Polycyclic aromatic hydrocarbons (PAHs) have long been recognised as potential carcinogens in animals in which biotransformation into reactive metabolites can lead to DNA damage. In animals PAHs metabolism mainly occurs in hepatic microsomes and is associated with the cytochrome p-450 mediated mixed functional oxidase (MFO) system. PAH metabolism in plants has been shown to occur via a similar enzyme system, but has received relatively little attention. This study is looking at how the plant species Plantago lanceolata metabolises benzo(a)pyrene (B(a)P), which is one of the PAHs whose metabolism has been studied extensively in animals. The aim of the work is to establish firstly that the B(a)P is taken up and secondly that it is biotransformed by the plant to products possibly similar to those found in animals. This work is achieved by using C-14-B(a)P along with whole body autoradiography, scintillation analysis and chromatography techniques to locate the B(a)P and its metabolites.