Characteristics of major volatile organic hazardous air pollutants in the urban air of Kaohsiung city

The concentrations and characteristics of volatile organic hazardous air pollutants (HAPs) in the urban city of Kaohsiung from motor vehicles and dense pollutant sources has become a national concern. To continuously monitor volatile organic HAPs, sampling sites were selected near the four air-quality monitoring stations established by Ethe nvironmental Protection Administration of Taiwan ROC, namely Nan-tz, Tso-ying, San-min and Hsiao-kang, from north to south. An on-site automated online monitor of volatile organic compounds (VOCs) was used for continuous monitoring. This study performed two consecutive days of 24-h monitoring of five volatile organic HAPs form August to October 2005 at the four monitoring sites, which cover the northern, central, and southern areas of Kaohsiung city. The average monitored concentration was 2.78–4.84 ppb for benzene, 5.90–9.66 ppb for toluene, 3.62–5.90 ppb for ethylbenzene, 3.73–5.34 ppb for m,p-xylene, 3.38–4.22 ppb for o-xylene, and 4.48–7.00 ppb for styrene. The average monitored concentrations of the major volatile organic HAPs tended to follow the pattern San-min > Nan-tz > Hsiao-kang > Tso-ying. Among all the species monitored in this study, toluene had the highest ambient concentration, followed by styrene, m,p-xylene, ethylbenzene, o-xylene, and benzene. The results showed that the concentration at night was higher than that in the day for toluene at Nan-tz, San-min, Hsiao-kang, and for benzene at Nan-tz and Hsiao-kang.     

城市化进程对城市热岛效应因子的对比分析

采用1990～2004年乌鲁木齐市和其郊区的温度差值作为衡量其城市热岛效应的标准,以乌鲁木齐市城市化七项指标作为城市热岛效应的形成因子.通过多元回归模型分析了各热岛效应因子对城市热岛的影响.文章主要结论包括乌鲁木齐市各热岛效应因子时城市热岛的影响是不同的,居民生活条件的改善和公共基础设施的改善减轻了热岛效应的影响,热岛效应也符合环境库兹涅茨曲线规律.     

Forensic Applications of Nitrogen and Oxygen Isotopes in Tracing Nitrate Sources in Urban Environments

Ground and surface waters in urban areas are susceptible to nitrate contamination from septic systems, leaking sewer lines, and fertilizer applications. Source identification is a primary step toward a successful remediation plan in affected areas. In this respect, nitrogen and oxygen isotope ratios of nitrate, in conjunction with hydrologic data and water chemistry, have proven valuable in urban studies from Austin, Texas, and Tacoma, Washington. In Austin, stream water was sampled during stremflow and baseflow conditions to assess surface and subsurface sources of nitrate, respectively. In Tacoma, well waters were sampled in adjacent sewered and un-sewered areas to determine if locally high nitrate concentrations were caused by septic systems in the un-sewered areas. In both studies, sewage was identified as a nitrate source and mixing between sewage and other sources of nitrate was apparent. In addition to source identification, combined nitrogen and oxygen isotopes were important in determining the significance of denitrification, which can complicate source assessment by reducing nitrate concentrations and increasing i 15 N values. The two studies illustrate the value of nitrogen and oxygen isotopes of nitrate for forensic applications in urba areas.     

Polychlorinated biphenyls contamination in urban soil of Shanghai: level, compositional profiles and source identification

Surface soil samples taken from 55 sampling sites at the urban areas of Shanghai were collected and analyzed for the occurrence of 144 polychlorinated biphenyls (PCBs) by GC-μECD. The results showed that totally 74 PCB congeners were identified and the mean concentration of total PCBs was 3057 ng kg⁻¹ with a range of 232 to 11325 ng kg⁻¹. Compared with the related reports, the level of PCBs contamination in this study was approximately equal to the global background value in soils, but higher than Chinese background for rural and urban soils. According to the compositional profiles of PCBs homologues, a higher proportion of low chlorinated (from tri-CBs to hexa-CBs) was observed. The results indicated that PCB15 + 13, PCB18, PCB28, PCB104 + 47 and PCB153 were the most dominant congeners among the identified PCBs. Through homologues analysis, cluster analysis and principal component analysis (PCA), it was found that PCBs were stretched from mixed local sources, and appeared to be mostly originated by Aroclor 1260- and 1254-like mixtures as well as some samples influenced by Aroclor 1232 and 1242. The correlation analysis showed the relatively good correlation among the PCB homologues and soil total organic carbon (TOC), suggesting important influence of soil TOC on PCBs contamination in soil matrix in Shanghai region. The toxic equivalency (TEQ) concentrations of these six dioxin-like PCBs detected in urban soil samples range from 2.71 to 24.9 pg kg⁻¹-PCDDeq with a mean 8.18 pg kg⁻¹-PCDDeq.     

Oxygen-containing polycyclic aromatic hydrocarbons (OPAHs) in urban soils of Bratislava, Slovakia: patterns, relation to PAHs and vertical distribution

We determined concentrations, sources, and vertical distribution of OPAHs and PAHs in soils of Bratislava. The ∑14 OPAHs concentrations in surface soil horizons ranged 88-2692 ng g⁻¹ and those of ∑34 PAHs 842-244,870 ng g⁻¹. The concentrations of the ∑9 carbonyl-OPAHs (r = 0.92, p = 0.0001) and the ∑5 hydroxyl-OPAHs (r = 0.73, p = 0.01) correlated significantly with ∑34 PAHs concentrations indicating the close association of OPAHs with parent-PAHs. OPAHs were quantitatively dominated by 9-fluorenone, 9,10-anthraquinone, 1-indanone and benzo[a]anthracene-7,12-dione. At several sites, individual carbonyl-OPAHs had higher concentrations than parent PAHs. The concentration ratios of several OPAHs to their parent-PAHs and contribution of the more soluble OPAHs (1-indanone and 9-fluorenone) to ∑14 OPAHs concentrations increased with soil depth suggesting that OPAHs were faster vertically transported in the study soils by leaching than PAHs which was supported by the correlation of subsoil:surface soil ratios of OPAH concentrations at several sites with K_OW.     

Impact of the global economic crisis on metal levels in particulate matter (PM) at an urban area in the Cantabria Region (Northern Spain)

Air pollution by particulate matter is well linked with anthropogenic activities; the global economic crisis that broke out in the last year may be a proper indicator of this close relationship. Some economic indicators show the regional effects of the crisis on the Cantabria Region. The present work aims to evaluate the impact of the economic crisis on PM10 levels and composition at the major city of the region, Santander. Some metals linked to anthropogenic activities were measured at Santander and studied by Positive Matrix Factorization; this statistical analysis allowed to identify three main factors: urban background, industrial and molybdenum-related factor. The main results show that the temporal trend of the levels of the industrial tracers found in the present study are well agree with the evolution of the studied economic indicators; nevertheless, the urban background tracers and PM10 concentration levels are not well correlated with the studied economic indicators.     

Presence,dissemination and removal of antibiotic resistant bacteria and antibiotic resistance genes in urban drinking water system: A review

Reviewed the change of ARGs and ARB in full-scale urban drinking water systems. Conventional processes are more promising than BAC process in ARGs removal. Mechanisms of ARGs enrichment and spread in BAC filter and DWDSs are discussed. Raise the need of future research on ARGs and ARB change in building plumbing systems. Antibiotic resistance in aquatic environment has become an important pollution problem worldwide. In recent years, much attention was paid to antibiotic resistance in urban drinking water systems due to its close relationship with the biosafety of drinking water. This review was focused on the mechanisms of antibiotic resistance, as well as the presence, dissemination and removal of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in the urban drinking water system. First, the presence of ARB and ARGs in the drinking water source was discussed. The variation of concentration of ARGs and ARB during coagulation, sedimentation and filtration process were provided subsequently, in which filtration was proved to be a promising technology to remove ARGs. However, biological activated carbon (BAC) process and drinking water distribution systems (DWDSs) could be incubators which promote the antibiotic resistance, due to the enrichment of ARGs and ARB in the biofilms attached to the active carbon and pipe wall. Besides, as for disinfection process, mechanisms of the inactivation of ARB and the promotion of conjugative transfer of ARGs under chlorine, ozone and UV disinfection were described in detail. Here we provide some theoretical support for future researches which aim at antibiotic resistance controlling in drinking water.     

中心城区河道基本消除黑臭的可行性措施和对策

概述了上海浦东新区水环境的现状,并对新区黑臭河道的数量、分布和污染程度作了详细的分析,探讨了新区河道黑臭的成因,针对新区已基本消除黑臭的骨干河道和黑臭的中心城区镇(街道)、村级河道分别提出了不同的污染防治可行性措施和对策。     

城市景观水体中腐殖酸的臭氧氧化去除

以南京师范大学德风园池底泥中提取的腐殖酸(HA)为研究对象,采用臭氧氧化技术对其进行去除,对初始pH值、混合气体流量、腐殖酸(HA)初始浓度以及水中常见离子等因素对去除效果的影响进行了研究。实验结果表明:腐殖酸(HA)的去除率随初始pH值的升高而提高,随混合气体流量减少而提高;当腐殖酸(HA)初始浓度为5 mg/L时,反应过程中溶液的UV254升高,紫外扫描结果发现,溶液在200~220 nm内出现杂乱的吸收峰,表明有新物质生成;水中常见的无机阴离子(CO32-、HCO3-)和二价金属离子(Ca2+、Cu2+)的存在会降低臭氧对腐殖酸(HA)的去除率。     

生态适宜度评价在城市总体规划环境影响评价中的应用——以宿迁市城市总体规划为例

以江苏省宿迁市城市总体规划为研究对象,在中心城区的用地布局和功能组团设置中引入土地利用生态适宜度评价的方法,建立中心城区生态适宜度评价指标体系,并借助GIS技术将数值计算和图形叠置有机结合,实现对中心城区布局进行生态适宜度评价的定量化研究方法,为中心城区的城市总体规划提供决策依据.