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91.
SO2 和氟化物对农作物的危害可通过症状、镜检和受害叶片的化学分析来鉴别 ,并从风向、与污染源距离、障碍物和叶片成熟程度几方面与作物病虫等影响因素相区别。排放浓度、接触时和作物本身抗性是影响危害程度的主要因素。应从治理污染、选种抗性强树木、避开作物敏感生育期、合理种植、加强施肥等方面采取措施加以防治  相似文献   
92.
城市水资源系统综合评价指标体系初探   总被引:8,自引:0,他引:8  
洪阳  曹静 《上海环境科学》2000,19(6):269-271
基于中国城市缺水的历史和现状,运用系统研究的方法,对影响城市水资源系统的自然禀赋、供水能力、用水效率和排放处理等子系统因素进行了综合分析,建立了包括目标层、准则层、指标层和方案层4个层次的城市水资源系统综合指标体系,并对评价程序和方法进行了理论分析,最后就目标层和准则层的可能评价结果建立了多维城市水资源综合评语集,对城市缺水类型进行分析,并可据此提出相应对策。  相似文献   
93.
阐述了欧洲国家的SEA系统,实施领域,规定、导则和立法以及培训等.分析了欧洲国家研究与实施SEA的经验、挑战和障碍(1)方法、技术和程序;(2)规定、导则和立法;(3)体制、政治支持性与公众参与;(4)信息来源与研究资金;(5)检查监督和质量保证.指出了注重教育培训、建立宣传网络,加强SEA研究,重视信息数据库开发,拓宽SEA试点研究领域4个发展趋势.  相似文献   
94.
Our previous study indicated that the current level of polycyclic aromatic hydrocarbons (PAHs) in Shenzhen soil is in the low-end of world soil PAH pollution. In this study, the fate of PAHs in the soil of Shenzhen was investigated. The mass inventories of Σ(27)PAHs and Σ(15)PAHs (defined as the sum of the 27 or 15 PAH compounds sought) in topsoil of Shenzhen were ~204 and ~152 metric tons, respectively. Fate estimation of Σ(15)PAHs shows that air-soil gaseous exchange is the primary environmental process with ~10,076 kg/year diffusing from soil to air. Rain washing (~1131 kg/year from air to soil) is the most important input pathway followed by wet (~17 kg/year) and dry deposition (~8 kg/year) to soils in Shenzhen. The transport of Σ(15)PAHs by soil erosion is a crucial loss process for soil PAHs in Shenzhen (1918 kg/year for water runoff and 657 kg/year for solid runoff from soil). Moreover, degradation is not ignorable at present (95 kg/year). Comparison of inventory and residue (defined as Σ(15)PAHs left in topsoils after all environmental loss processes) suggested that input and loss of high molecular weight PAHs for Shenzhen's soil reached apparent equilibrium. Soil PAH pollution in Shenzhen will stay in a quasi-steady state for a long period and the natural environmental processes can not significantly reduce the pollution.  相似文献   
95.
To determine the incidence of organochlorine pesticides (OCPs) in soil in a rapid urbanization region, soil samples from various land use types in Shenzhen were collected in winter, 2007. The concentration of dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs) ranged from non-detected to 149 ng g(-1) and 19 to 88 ng g(-1), respectively. The highest levels of OCPs were observed in soil from traffic and industry areas, reflecting that intensive human disturbance make the soil pollution accumulation more disperse. HCHs and DDTs profiles revealed that the sources were associated mainly with lindane and technical DDTs, respectively, while HCHs in the soil of Shenzhen might originate from both recent and historical sources. The loss of OCPs by soil erosion will enter surface runoff and impose impact on the water environment. Non-dietary exposure estimation indicates that children were the most sensitive group. The average daily exposure to OCPs for males was more serious than for females. Non-dietary exposure to DDTs and HCHs in residential blocks of Shenzhen were far below the acceptable daily intake recommended by the Food and Agriculture Organization/World Health Organization.  相似文献   
96.
垃圾填埋场建设项目的主要环境问题包括:渗沥液排放、地下水环境污染、大气环境污染、噪声污染、景观变化和环境安全。根据工作经验,建立了包括建设项目基本情况、生态环境影响、社会环境影响、生态环境保护措施四大类调查监测指标为核心的环保验收调查指标体系,提出了文件资料核实、现场勘查、遥感调查、公众意见调查、环境监测和摄影法为主的建设项目竣工环保验收调查技术方法。  相似文献   
97.
通过田间定位试验,研究了石灰(L)、钙镁磷肥(G)、泥炭(P)、猪粪(M)、石灰 泥炭(L P)、石灰 猪粪(L M)、钙镁磷肥 泥炭(G P)、钙镁磷肥 猪粪(G M)等改良材料对新罗区特钢厂附近的重金属污染田的长期改良效应.结果表明:大部分处理可提高土壤的pH值、有机质含量,降低了土壤的有效锌含量,石灰 泥炭、钙镁磷肥 泥炭的改良效果要优于单施有机、中性化改良剂和其它处理,和对照相比,有效锌含量和糙米锌含量最高分别降低了59.2%、36.2%.  相似文献   
98.
The degradation of polyacrylamide (PAM) in simulate wastewater was studied in UV/Fenton/C4H4O62? system. The factors such as molecular ratio of H2O2/Fe2+/C4H4O62?, pH, and the dosage of Fenton reagent that could affect the PAM degradation in the UV/Fenton/C4H4O62? system were investigated. The experimental results showed that adding C4H4O62? to UV/Fenton system could form photosensitive ferrous complexes, which led to higher degradation efficiency of PAM. The degradation rate of PAM could be up to 95.2% under the following conditions: the concentration of H2O2, Fe2+, and C4H4O62? were 22.5, 2.25, and 2.25 mmol/L, respectively (i.e., molecular ratio of H2O2/Fe2+/C4H4O62? was 10:1:1), the pH value was 3.0.  相似文献   
99.
Density functional theory (DFT) has been used to investigate the reaction pathways with steam reforming of glycerol under cold plasma conditions. Total energies, energy barriers, and reaction enthalpies at 298.15 K have been calculated at the GGA/PW91/DNP level. The calculation shows that, with the presence of steam, the energy barrier of glycerol conversion is reduced and the conversion from glycerol to H2 and CO is promoted under cold plasma conditions. The formation of syngas was through a multi-step pathway via the conversion of OHCH2CHOH, CH2OH, CH2O, HCO,·and CH3, while the recombination of H generated extra H2. The synthesis of hydrocarbons are from the recombination of·CH3,·CH2, and·CH, which could be primarily generated through glycerol dissociation. The structure of glycerol anion was also studied in this work, and it was less stable than the neutral molecule. The route for the formation of OHCH2CHOH·and CH2OH·from glycerol anion is thermodynamically favorable.  相似文献   
100.

Purpose

The aim of this paper is to understand the sustainability of urban spatial transformation in the process of rapid urbanization, and calls for future research on the demographic and economic dimensions of climate change. Shanghai towards its transformation to a metropolis has experienced vast socioeconomic and ecological change and calls for future research on the impacts of demographic and economic dimensions on climate change. We look at the major questions (1) to explore economic and demographic growth, land use and land-cover changes in the context of rapid economic and city growth, and (2) to analyze how the demography and economic growth have been associated with the local air temperature and vegetation.

Method

We examine urban growth, land use and land-cover changes in the context of rapid economic development and urbanization. We assess the impact of urban expansion on local air temperature and vegetation. The analysis is based on time series data of land use, normalized difference vegetation index (NDVI), and meteorological, demographic and economic data.

Results and discussion

The results indicate that urban growth has been driven by mass immigration; as a consequence of economic growth and urban expansion, a large amount of farmland has been converted to paved road and residential buildings. Furthermore, the difference between air temperature in urban and exurban areas has increased rapidly. The decrease of high mean annual NDVI has mainly occurred around the dense urban areas.  相似文献   
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