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631.
632.
上海市PM2.5的物理化学特征及其生物活性研究 总被引:3,自引:1,他引:2
采集了上海市区和郊区春季和夏季的大气PM2.5样品,分析了市区和郊区春夏2季PM2.5质量浓度变化的规律,使用PIXE(Proton Induced X-ray Emission)分析技术获得S、K、Ca、Ti、Cr、Mn、Fe、Ni、Cu、Zn、As、Se、Br、Sr、Pb等15种元素的质量浓度.结果表明,上海PM2.5中化学元素的质量浓度在春季 (5?038.6 ng·m-3) 比在夏季 (3?810.6 ng·m-3) 高,春季郊区(2?528.9 ng·m-3) 和市区(2?509.7 ng·m-3) PM2.5中化学元素的质量浓度相当,夏季市区样品 (1?674.2 ng·m-3) 中化学元素质量浓度的总量比郊区(2?136.3 ng·m-3) 的低,但来自人为污染的化学元素 (Cr、Mn、Ti、Ni、Cu、Zn、As、Br、Sr、Pb) 在市区PM2.5中的含量较高;场发射扫描电镜 (FESEM) 分析显示,上海PM2.5主要由烟尘集合体、燃煤飞灰、矿物颗粒、生物质颗粒和不明物质组成,质粒DNA评价揭示上海市区PM2.5比郊区的具有更强的生物活性,主要原因可能在于市区样品中含有较高的重金属元素和较多的烟尘集合体. 相似文献
633.
Exposure to polybrominated diphenyl ethers among workers at an electronic waste dismantling region in Guangdong, China 总被引:9,自引:1,他引:8
Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants. The aim of the present study was to evaluate the PBDE serum levels in residents from an electronic waste dismantling region, residents living within 50 km of the dismantling region, and a referent group with no occupational PBDE exposure. Fourteen PBDE congeners including BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, BDE-196, BDE-197, BDE-203, BDE-206, BDE-207, BDE-208 and BDE-209 were quantified in these three groups by gas chromatography-negative chemical ionization (NCI) mass spectrometry in selected ion monitoring (SIM) mode. We found that the levels of all PBDE congeners in serum of residents from electronic waste dismantling region were significantly higher than those in the two other groups. The referents showed the lowest PBDE levels. Concentrations of congeners with a high number of bromine substituents, i.e., hepta- to decaBDEs in occupational exposure workers were 11-20 times higher than those in the referent group. BDE-209 was the dominant congener. The highest concentration of BDE-209 was observed among the electronic waste dismantling workers, and it was 3436 ng g(-1) lipid weight (ng g(-1) l.w.), which is the highest concentration of BDE-209 in humans worldwide. Some higher brominated PBDE congeners such as BDE-197, BDE-207 and BDE-208 also showed elevated concentrations in dismantling workers. This study confirms that BDE-209 is released to the environment and can bioaccumulate in the blood of electronic waste dismantling workers, and extensive occupational exposure to PBDEs leads to elevated concentrations of all PBDE congeners in serum. 相似文献
634.
Distribution of PBDEs in air particles from an electronic waste recycling site compared with Guangzhou and Hong Kong, South China 总被引:4,自引:0,他引:4
Air samples of total suspended particles (TSP, particles less than 30-60 microm), and particles with aerodynamic diameter smaller than 2.5 microm (PM(2.5)) were collected simultaneously at Guiyu (an electronic waste recycling site), three urban sites in Hong Kong and two urban sites in Guangzhou, South China from 16 August to 17 September 2004. Twenty-two PBDE congeners (BDE-3, -7, -15, -17, -28, -49, -71, -47, -66, -77, -100, -119, -99, -85, -126, -154, -153, -138, -156, -184, -183, -191) in TSP and PM(2.5) were measured. The results showed that the overall average concentrations of TSP and PM(2.5) collected at Guiyu were 124 and 62.1 microg m(-3), respectively. The monthly concentrations of the sum of 22 BDE congeners contained in TSP and PM(2.5) at Guiyu were 21.5 and 16.6 ng m(-3), with 74.5 and 84.3%, contributed by nine congeners (BDE-28, -47, -66, -100, -99, -154, -153, -183 and -191 respectively). This pattern was similar to Tsuen Wan site of Hong Kong. Two urban sites of Guangzhou had the same congener pattern, but were different from Yuen Long and Hok Tsui sites of Hong Kong. The results also showed that the amount of mono to penta brominated congeners, which are more toxic, accounted for 79.4-95.6% of Sigma(22)PBDEs from all sites. All congeners tested in Guiyu were up to 58-691 times higher than the other urban sites and more than 100 times higher than other studies reported elsewhere. The higher concentration in the air was due to heating or opening burning of electronic waste since PBDEs are formed when plastics containing brominated flame retardants are heated. 相似文献
635.
636.
We report on the effects of forest management practices of understory removal and N-fixing species (Cassia alata) addition on soil
CO2 fluxes in an Eucalyptus urophylla plantation (EUp), Acacia crassicarpa plantation (ACp), 10-species-mixed plantation (Tp), and
30-species-mixed plantation (THp) using the static chamber method in southern China. Four forest management treatments, including
(1) understory removal (UR); (2) C. alata addition (CA); (3) understory removal and replacement with C. alata (UR+CA); and (4)
control without any disturbances (CK), were applied in the above four forest plantations with three replications for each treatment.
The results showed that soil CO2 fluxes rates remained at a high level during the rainy season (from April to September), followed by
a rapid decrease after October reaching a minimum in February. Soil CO2 fluxes were significantly higher (P < 0.01) in EUp (132.6
mg/(m2·hr)) and ACp (139.8 mg/(m2·hr)) than in Tp (94.0 mg/(m2·hr)) and THp (102.9 mg/(m2·hr)). Soil CO2 fluxes in UR and CA
were significantly higher (P < 0.01) among the four treatments, with values of 105.7, 120.4, 133.6 and 112.2 mg/(m2·hr) for UR+CA,
UR, CA and CK, respectively. Soil CO2 fluxes were positively correlated with soil temperature (P < 0.01), soil moisture (P < 0.01),
NO3?-N (P < 0.05), and litterfall (P < 0.01), indicating that all these factors might be important controlling variables for soil CO2
fluxes. This study sheds some light on our understanding of soil CO2 flux dynamics in forest plantations under various management
practices. 相似文献
637.
Li Li Changhong Chen Cheng Huang Haiying Huang Gangfeng Zhang Yangjun Wang Minghua Chen Hongli Wang Yiran Chen D. G. Streets Jiamo Fu 《环境科学学报(英文版)》2011,23(7):1150-1157
Ozone has become one of the most important air pollution issues around the world. This article applied both O3/(NOy-NOx) and
H2O2/HNO3 indicators to analyze the ozone sensitivity in urban and rural areas of Shanghai, with implementation of the MM5-CMAQ
modeling system in July, 2007. The meteorological parameters were obtained by using the MM5 model. A regional emission inventory
with spatial and temporal allocation based on the statistical data has been developed to provide input emission data to the MM5-CMAQ
modeling system. Results showed that the ozone concentrations in Shanghai show clear regional differences. The ozone concentration
in rural areas was much higher than that in the urban area. Two indicators showed that ozone was more sensitive to VOCs in urban
areas, while it tended to be NOx sensitive in rural areas of Shanghai. 相似文献
638.
Multivariate analysis of surface water quality in the Three Gorges area of
China and implications for water management 总被引:3,自引:0,他引:3
Multivariate statistical techniques, cluster analysis, non-parametric tests, and factor analysis were applied to analyze a water quality
dataset including 13 parameters at 37 sites of the Three Gorges area, China, from 2003–2008 to investigate spatio-temporal variations
and identify potential pollution sources. Using cluster analysis, the twelve months of the year were classified into three periods of lowflow
(LF), normal-flow (NF), and high-flow (HF); and the 37 monitoring sites were divided into low pollution (LP), moderate pollution
(MP), and high pollution (HP). Dissolved oxygen (DO), potassium permanganate index (CODMn), and ammonia-nitrogen (NH4
+-N)
were identified as significant variables affecting temporal and spatial variations by non-parametric tests. Factor analysis identified that
the major pollutants in the HP region were organic matters and nutrients during NF, heavy metals during LF, and petroleum during HF.
In the MP region, the identified pollutants primarily included organic matter and heavy metals year-around, while in the LP region,
organic pollution was significant during both NF and HF, and nutrient and heavy metal levels were high during both LF and HF. The
main sources of pollution came from domestic wastewater and agricultural activities and runoff; however, they contributed differently
to each region in regards to pollution levels. For the HP region, inputs from wastewater treatment plants were significant; but for MP
and LP regions, water pollution was more likely from the combined effects of agriculture, domestic wastewater, and chemical industry.
These results provide fundamental information for developing better water pollution control strategies for the Three Gorges area. 相似文献
639.
对博尚水库及入库河流水环境现状、污染特性和成因分析评价以及未来可能出现的问题,并针对博尚水库及库区上游入库河流的实际情况提出了水环境和水资源综合保护治理措施。主要以云南省水环境监测中心临沧市分中心水质实测资料为依据,按照地表水环境质量标准(GB3838-2002)和国家环境监测总站制定的《湖泊水库富营养化评分与分类标准》作为评价标准进行单因子评价及富营养化评价标准。 相似文献
640.
流域梯级电站开发日益使河流湖库化,特别是建在流域下游的水库尤为明显,湖库富营养化已成为水库的主要生态环境问题,备受中外学者关注。本文通过对红岩水电站库区富营养化程度预测判别,分析了中小型水电站库区蓄水后富营养化变化趋势,提出中小型水电站库区富营养化控制对策,为湖库区水质保护与改善提供参考。 相似文献