Photolysis of polycyclic aromatic hydrocarbons on soil surfaces under UV irradiation

Photolysis of some polycyclic aromatic hydrocarbons (PAHs) on soil surfaces may play an important role in the fate of PAHs in the environment.Photolysis of PAHs on soil surfaces under UV irradiation was investigated.The effects of oxygen,irradiation intensity and soil moisture on the degradation of the three PAHs were observed.The results showed that oxygen,soil moisture and irradiation intensity enhanced the photolysis of the three PAHs on soil surfaces.The degradation of the three PAHs on soil surfaces is related to their absorption spectra and the oxidation-half-wave potential.The photolysis of PAHs on soil surfaces in the presence of oxygen followed pseudo first-order kinetics.The photolysis half-lives ranged from 37.87 days for benzo[a]pyrene to 58.73 days for phenanthrene.The results indicate that photolysis is a successful way to remediate PAHs-contaminated soils.     

Influence of fuel moisture, charge size, feeding rate and air ventilation conditions on the emissions of PM, OC, EC, parent PAHs, and their derivatives from residential wood combustion

Controlled combustion experiments were conducted to investigate the influence of fuel charge size, moisture, air ventilation and feeding rate on the emission factors (EFs) of carbonaceous particulate matter, parent polycyclic aromatic hydrocarbons (pPAHs) and their derivatives from residential wood combustion in a typical brick cooking stove. Measured EFs were found to be independent of fuel charge size, but increased with increasing fuel moisture. Pollution emissions from the normal burning under an adequate air supply condition were the lowest for most pollutants, while more pollutants were emitted when an oxygen deficient atmosphere was formed in the stove chamber during fast burning. The impacts of these factors on the size distribution of emitted particles was also studied. Modified combustion efficiency and the four investigated factors explained 68%, 72%, and 64% of total variations in EFs of PM, organic carbon, and oxygenated PAHs, respectively, but only 36%, 38% and 42% of the total variations in EFs of elemental carbon, pPAHs and nitro-PAHs, respectively.     

滇池PAHs的沉积记录、来源及其生态风险评估

采用GC/MS方法分析了滇池沉积柱中16种美国EPA优控的多环芳烃(PAHs)的垂直分布状况,并对其来源变化及生态风险进行了分析和评估.研究表明:滇池沉积柱中PAHs的含量范围为558～6418 ng·g-1,并在20世纪90年代初达到峰值,这明显不同于发达国家的同类研究,也与国内沿海地区和偏远湖泊的相关研究有所不同.滇池沉积物中的PAHs主要来自当地的家庭燃煤、木材和生物秸秆等的低温燃烧过程,但工业燃煤和机动车尾气等高温燃烧过程释放的PAHs的相对含量近年来有明显增加的趋势.风险评估结果显示,滇池中上层沉积物中的PAHs可能存在潜在的生态风险,而这些生态风险主要来自低环数的NAP、FLU、PHEN和高环数的BbF、BaP、DBA等.     

煤矸石堆放对土壤环境PAHs污染的影响

为探讨煤矸石堆放对土壤环境的有机污染效应,以典型煤矸石区——平煤十二矿为例,利用GC-MS技术对煤矸石、表层土壤及降尘样品中多环芳烃(PAHs)含量及化学组成特征进行了检测,将PAHs空间分布、环数分布、优势组成与分子标志物参数相结合,定性剖析了煤矸石堆放对表层土壤PAHs污染的贡献.煤矸石、降尘和土壤表层中PAHs综合分析表明,煤矸石堆积区表层土壤US EPA 16种优控PAHs(PHA₁₆)总量为0.94~5.66 μg·g^-1,属严重污染;表层土壤PAH₁₆总量与煤矸石山距离呈负相关关系;煤矸石、降尘及表层土壤中PAHs均为富3环特征,以菲、苯并荧蒽、、荧蒽及芘为优势组成;煤矸石扬尘直降、煤矸石燃烧、原煤煤尘降落和燃烧对土壤环境PAHs均有输入,但近源区煤矸石扬尘直降贡献明显,煤矸石扬尘使煤矿区土壤环境中PAHs污染具有面源贡献的特点,应引起重视.     

聊城古云地区地下水环境质量评价与分析

通过对古云地区地下水开发利用调查和污染取样分析,结合实际情况选取了15项评价因子,采用内梅罗综合指数法按照地下水质量评价标准(GB/T 14848-93)进行水质评价。结果表明:古云地区浅层地下水已受到较为严重的污染,全区均为Ⅳ级水和Ⅴ级水,且二者所占比例为Ⅳ级水占25%,Ⅴ级水占75%。污染物以石油类、酚类为主,该类污染物主要分布在西部石油开采区和金堤河沿线。部分样品中砷污染也较为严重,主要分布于古云地区中部。     

湟水河小流域地下水脆弱性评价

湟水河地处西北高原干旱地区,针对其流域地下水的特点,选取包气带介质、水位埋深、含水层介质、含水层厚度、净补给量和地形坡度共6个指标并运用三标度AHP法为各个指标赋予权重,构建了改进的DRASTIC模型。运用改进DRASTIC模型对湟水河的小流域范围的地下水脆弱性进行了评价。结果表明,湟水河沿岸的部分地区和西堡村附近地下水脆弱性高,地下水易受到污染。与传统DRASTIC模型相比,改进模型与实际情况更加吻合。     

包头市水体中放射性水平分析

随着世界稀土产业的蓬勃发展,包头市稀土生产规模不断扩大,白云鄂博矿开发利用是否对包头市水体有放射性的影响,成为人们一直关注的问题。本文通过归纳总结大量的数据,分析了2008～2012年包头市水体中的放射性水平,包头市昭君坟断面的黄河水、居民饮用自来水及地下水放射性水平均处于国家安全范围内,没有受到放射性污染。     

有机污染物多环芳烃检测方法及进展

就近年来有机污染物多环芳烃检测方法及进展作一综述,方法包括高效液相色谱法、气相色谱一质谱联用法、毛细管电泳分析法、荧光法、免疫检测法以及表面增强拉曼散色光谱检测法,为在环境监测、食品检测等方面的应用提供了依据。     

吕梁市PM2.5中多环芳烃的来源解析及健康风险评价

为探索吕梁地区PM_2.5中多环芳烃的季节变化、健康风险和潜在来源,于2018年10月23日至2019年7月1日对离石区(市区)和孝义市(郊区)进行PM_2.5样品采集,利用气相色谱-质谱联用仪(GC-MS)测定了14种多环芳烃浓度.总多环芳烃的浓度年均值为95.50 ng·m^-3,主要以5～6环为主(49.7%),3环占比较低(8.3%);吕梁市多环芳烃浓度呈现冬季>秋季>春季>夏季的季节性变化规律,市区浓度年均值(130.47 ng·m^-3)高于郊区(84.4 ng·m^-3);增量终身致癌风险和蒙特卡洛模拟结果均表明吕梁市多环芳烃毒性服从成人>青年>儿童的规律,除夏季外,离石区增量终身致癌风险值均在10^-6～10^-4之间,远高于孝义市,表明市区存在较高的多环芳烃潜在风险;通过采用特征比值法和正定矩阵因子分解模型表明,吕梁市多环芳烃主要来自于煤和生物质的燃烧(61.9%)和机动车尾气排放(38.1%),由后...     

Characterization, reactivity, source apportionment, and potential source areas of ambient volatile organic compounds in a typical tropical city

Based on one-year observation, the concentration, sources, and potential source areas of volatile organic compounds (VOCs) were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haikou, China. The results showed that the annual average concentration of total VOCs (TVOCs) was 11.4 ppbV, and the composition was dominated by alkanes (8.2 ppbV, 71.4%) and alkenes (1.3 ppbV, 20.5%). The diurnal variation in the concentration of dominant VOC species showed a distinct bimodal distribution with peaks in the morning and evening. The greatest contribution to ozone formation potential (OFP) was made by alkenes (51.6%), followed by alkanes (27.2%). The concentrations of VOCs and nitrogen dioxide (NO₂) in spring and summer were low, and it was difficult to generate high ozone (O₃) concentrations through photochemical reactions. The significant increase in O₃ concentrations in autumn and winter was mainly related to the transmission of pollutants from the northeast. Traffic sources (40.1%), industrial sources (19.4%), combustion sources (18.6%), solvent usage sources (15.5%) and plant sources (6.4%) were identified as major sources of VOCs through the positive matrix factorization (PMF) model. The southeastern coastal areas of China were identified as major potential source areas of VOCs through the potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) models. Overall, the concentration of ambient VOCs in Haikou was strongly influenced by traffic sources and long-distance transport, and the control of VOCs emitted from vehicles should be strengthened to reduce the active species of ambient VOCs in Haikou, thereby reducing the generation of O₃.