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311.
Yichen Yang Mianqiang Xue Zhenming Xu Chen Huang 《Journal of Material Cycles and Waste Management》2013,15(4):556-563
The aim of the study was to determine the potential environmental contamination in a typical factory for recycling waste electrical and electronic equipment in Shanghai. Heavy metals (Cr, Ni, Cu, Zn, Cd, Pb) in the soil around the factory have been evaluated in this paper. Compared with the background value, the concentrations of six metals detected in all the samples were higher, which showed that toxic metals were released into soil around the factory. Compared with the Environmental Quality Standards for Soils, China grade III, all the six metals are under soil guidelines. The non-cancer risk in different directions from the factory was in the order of: the north > the west > the south > the east. For inhalation and ingestion, the non-cancer risk in the soil west of the factory was biggest. Nevertheless, the non-cancer risk in the soil north of the factory was the biggest for dermal contact. The trend of cancer risk was the west > the south > the north > the east. The non-cancer risk and the carcinogenic risk for Cr, Ni, and Cd were all below the limiting value. This study might provide a reference for the risk assessment involved in electronic waste management and recycling activities. 相似文献
312.
Polybrominated diphenyl ethers and organochlorine pesticides in sewage sludge of wastewater treatment plants in China 总被引:4,自引:0,他引:4
The concentrations of chemicals in sewage sludge from wastewater treatment plants (WWTPs) may relate to their levels of use and environmental pollution in the region. In this work, sludge samples were collected from 31 WWTPs in 26 cities in China and analyzed for polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs). The concentrations of SigmaPBDE (sum of congeners 17, 28, 47, 66, 71, 85, 99, 100, 138, 153, 154, and 183) ranged from 6.2 to 57ng/g (dw). The concentration of decabromodiphenyl ether (BDE-209) ranged from below limit of detection (LOD) to 1109ng/g (dw) (with a median of 27ng/g (dw)), and averaged 55% (median 69%) of the total PBDEs. These levels are about 10-100 times lower than those found in Europe and North America. PBDE levels in sludge were not found to depend on the location and capacity of the WWTPs. Concentrations of hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethane (DDTs) and its major degradation products, and hexachlorobenzene (HCB) ranged from below detection limit to 167ng/g (dw), 11 to 1065ng/g (dw), and 7.5 to 319ng/g (dw), respectively. The major DDT degradation products were p,p'-DDE and p,p'-DDD. The major hexachlorocyclohexane (HCH) isomer in sludge is beta-HCH, reflecting its higher affinity to solids and resistance to degradation than other isomers. 相似文献
313.
基于区域间水环境容量分配的控制指标和公平性准则分析,应用水环境基尼系数概念,以定量表达各公平性准则;并将各控制指标的水环境基尼系数均达到最小值作为界定多目标公平性的标准值。以此为基础,以各区域水环境容量分配比例为搜索变量,以水环境基尼系数达到多目标公平性标准值为目标,采用多目标最优化方法确定区域间水环境容量公平分配方案。应用该方法,对长乐江流域水环境容量在区域间的分配进行了实例分析。结果表明,将水环境基尼系数作为水环境容量分配结果的公平性衡量指标具有客观性,确定的水环境容量公平分配方案体现了多目标公平性。水环境基尼系数法可以推广至同一层面、具有可比性的排污单位间水环境容量公平分配问题上,且方法简单、可靠。 相似文献
314.
Quantitative Identification of Disturbance Thresholds in Support of Aquatic Resource Management 总被引:3,自引:0,他引:3
The identification of disturbance thresholds is important for many aspects of aquatic resource management, including the establishment
of regulatory criteria and the identification of stream reference conditions. A number of quantitative or model-based approaches
can be used to identify disturbance thresholds, including nonparametric deviance reduction (NDR), piecewise regression (PR),
Bayesian changepoint (BCP), quantile piecewise constant (QPC), and quantile piecewise linear (QPL) approaches. These methods
differ in their assumptions regarding the nature of the disturbance-response variable relationship, which can make selecting
among the approaches difficult for those unfamiliar with the methods. We first provide an overview of each of the aforementioned
approaches for identifying disturbance thresholds, including the types of data for which the approaches are intended. We then
compare threshold estimates from each of these approaches to evaluate their robustness using both simulated and empirical
datasets. We found that most of the approaches were accurate in estimating thresholds for datasets with drastic changes in
responses variable at the disturbance threshold. Conversely, only the PR and QPL approaches performed well for datasets with
conditional mean or upper boundary changes in response variables at the disturbance threshold. The most robust threshold identification
approach appeared to be the QPL approach; this method provided relatively accurate threshold estimates for most of the evaluated
datasets. Because accuracy of disturbance threshold estimates can be affected by a number of factors, we recommend that several
steps be followed when attempting to identify disturbance thresholds. These steps include plotting and visually inspecting
the disturbance-response data, hypothesizing what mechanisms likely generate the observed pattern in the disturbance-response
data, and plotting the estimated threshold in relation to the disturbance-response data to ensure the appropriateness of the
threshold estimate. 相似文献
315.
礼仪是一种文化,也是一种艺术.面对社会对高职学生素质问题的指责,面对高职院校教师对学生素质现状的忧虑,要充分发挥礼仪在推行素质教育中的桥梁作用.在高职院校实施礼仪教育可以从两个方面进行:一是重视礼仪的学习,挖掘礼仪的魅力;二是根据高职学生的特点,改革礼仪教学. 相似文献
316.
从组织保障、法规政策、监督管理、经济、技术等角度提出了保障南水北调工程环境管理工作有效实施的保障措施,并从加强统一领导和部门协调,推广和完善环境保护目标责任制,法制建设,对重大决策、规划与建设项目实施全过程监督和环境监测能力建设等方面进行了初步探讨. 相似文献
317.
Li Yang Rui Zhang Hairui Duo Wei Zhang Zhe Jiang Yueheng Ren Jiang Lv Mujiao Huang Fuyuan Liu Muhammad Shahid Xiaofeng Luan 《Russian Journal of Ecology》2017,48(6):569-575
Long-term dynamics of population decline can improve the conservation perspectives and strategies for endanger species. In China, new gazetteers having systematic compilation and wide geographical coverage can be considered as an important complementary for reconstruction historical distribution. For historical and cultural reasons, an endangered species–lynx (Lynx lynx) was recorded regularly in new gazetteers. Therefore, the aim of this paper was to evaluate the population distribution in Northeast China from the 1950s to 2014. The data show that Felis lynx was widely distributed in Northeast China in the 1950s, but the number of the occurrence records have been significantly reduced by 85.6% in the last 60 years. This research also enlightens us that the new gazetteers can contribute to data shortage and it would be helpful to conservation biology. 相似文献
318.
Xi Zhang Kai Zhang Huiping Liu Wenli Lv Masahide Aikaw Bing Liu Jinhe Wang 《环境科学学报(英文版)》2020,32(9):91-98
To investigate the secondary formation and pollution sources of atmospheric particles in urban Beijing, PM2.5 and its chemical components were collected and determined by URG-9000D ambient ion monitor (AIM) from March 2016 to January 2017. Among water-soluble ions (WSIs), NO3?, SO42- and NH4+ (SNA) had the largest proportion (77.8%) with the total concentration of 23.8 μg/m3. Moreover, as fine particle pollution worsened, the NO3?, SO42- and NH4+ concentrations increased basically, which revealed that secondary aerosols were the main cause of particle pollution in Beijing. Furthermore, the particle neutralization ratio (1.1), the ammonia to sulfate molar ratio (3.4) and the nitrate to sulfate molar ratio (2.2) showed that secondary aerosols are under ammonium-rich conditions with the main chemical forms of NH4NO3 and (NH4)2SO4, and vehicle emission could be the main anthropogenic source of secondary aerosols in Beijing. Source analysis further indicated that secondary aerosols, solid fuel combustion, dust and marine aerosol were the principal pollution sources of PM2.5, accounting for about 46.1%, 22.4% and 13.0%, respectively, and Inner Mongolia and Hebei Provinces could be considered as the main potential sources of PM2.5 in urban Beijing. In addition, secondary formation process was closely related with gaseous precursor emission amounts (SO2, NO2, NH3 and HONO), atmospheric ozone concentration (O3), meteorological conditions (temperature and relative humidity) and particle components. Sensitive analysis of the thermodynamic equilibrium model (ISORROPIA II) revealed that controlling total nitrate (TN) is the effective measure to mitigate fine particle pollution in Beijing. 相似文献
319.
Xianwei Wang Xiuzhen Li Yuanman Hu Jiujun Lv Ju Sun Zongmei Li Zhifeng Wu 《环境科学学报(英文版)》2010,22(7):1057-1066
Boreal peatlands represent a large global carbon pool.The relationships between carbon mineralization,soil temperature and moisture in the permafrost peatlands of the Great Hing'an Mountains,China,were examined.The CO2 emissions were measured during laboratory incubations of samples from four sites under different temperatures(5,10,15,and 20°C) and moisture contents(0%,30%,60%,100% water holding capacity(WHC) and completely water saturated).Total carbon mineralization ranged from 15.51 to 112.92 mg C under the treatments for all sites.Carbon mineralization rates decreased with soil depth,increased with temperature,and reached the highest at 60% WHC at the same temperature.The calculated temperature coefficient(Q10) values ranged from 1.84 to 2.51 with the soil depths and moisture.However,the values were not significantly affected by soil moisture and depth for all sites due to the different peat properties(P 0.05).We found that the carbon mineralization could be successfully predicted as a two-compartment function with temperature and moisture(R2 0.96) and total carbon mineralization was significantly affected by temperature and moisture(P 0.05).Thus,temperature and moisture would play important roles in carbon mineralization of permafrost peatlands in the Great Hing'an Mountains,indicating that the permafrost peatlands would be sensitive to the environment change,and the permafrost peatlands would be potentially mineralized under future climate change. 相似文献
320.
Particulate matter diameter ≤ 2.5 μm (PM2.5) causes direct harm to human health. Finding forms of urban forest systems that with the ability to reduce the amount of particulate matter in air effectively is the aim of this study. Five commonly cultivated kinds of urban forest types were studied in Beijing city at three stages of leaf growth. Results show that the urban forest system is capable of storing and capturing dust from the air. The types of shrubs and broadleaf trees that have the ability to capture PM2.5 from the air are most effective when leaves have fully developed. In the leafless season, the conifer and mixed tree types are the most effective in removing dust from the air. For all kinds of forest types and stages of leaf growth, the PM2.5 concentration is highest in the morning but lower in the afternoon and evening. Grassland cannot control particles suspended in the air, but can reduce dust pollution caused by dust from the ground blown by the wind back into the air. 相似文献