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111.
Wilhelm Hoeflinger 《中国人口.资源与环境(英文版)》2010,8(4)
The characteristics of fine particulate pollution(PM10and PM25)were measured at urban and suburban sites in Jinan during the 2008-2009 heating and non-heating seasons.The results showed that PM10 and PM2.5 pollution was quite serious,and PM mass concentration was higher during the heating season than the non-heating season.PM was the highest in the chemical factory and lowest in the development zone.The mass concentrations of PM10 and PM2.5 were linearly related,and the mass concentration ratio of PM2.5/PM10 was up to 0.59 in urban areas.PM pollution in Jinan was related to local meteorological factors: PM2.5 mass concentration and humidity were positively correlated,and PM2.5mass concentration was negatively correlated with both click on the temperature and wind speed,although wind speed varied more. 相似文献
112.
Uptake of uranium and thorium by native and cultivated plants 总被引:2,自引:0,他引:2
Shtangeeva I 《Journal of environmental radioactivity》2010,101(6):458-6946
Large part of available literature on biogeochemistry of uranium and thorium refers to the studies performed either in highly contaminated areas or in nutrient solutions that have been artificially ‘spiked’ with radionuclides. Effects of background levels of natural radioactivity on soil-grown plants have not been studied to the same extent. In this paper, we summarised results of greenhouse and field experiments performed by the author from 2000 to 2006. We examined some of the factors affecting transfer of U and Th from soil to plants, differences in uptake of these radionuclides by different plants, relationships between U and Th in soil and in plants, and temporal variations of U and Th in different plant species. Concentrations of radionuclides (critical point for experimental studies on biogeochemistry of U and Th - rare trace elements in non-contaminated regions) and essential plant nutrients and trace elements were determined by instrumental neutron activation analysis. 相似文献
113.
Heather E. Golden Elizabeth W. Boyer Michael G. Brown S. Thomas Purucker René H. Germain 《Journal of the American Water Resources Association》2009,45(4):945-962
Abstract: Nitrate‐nitrogen (NO3‐N) concentrations in stream water often respond uniquely to changes in inter‐annual conditions (e.g., biological N uptake and precipitation) in individual catchments. In this paper, we assess (1) how the spatial distribution of NO3‐N concentrations varies across a dense network of nonnested catchments and (2) how relationships between multiple landscape factors [within whole catchments and hydrologically sensitive areas (HSAs) of the catchments] and stream NO3‐N are expressed under a variety of annual conditions. Stream NO3‐N data were collected during two synoptic sampling events across >55 tributaries and two synoptic sampling periods with >11 tributaries during summer low flow periods. Sample tributaries drain mixed land cover watersheds ranging in size from 0.150 to 312 km2 and outlet directly to Cayuga Lake, New York. Changes in NO3‐N concentration ratios between each sampling event suggest a high degree of spatial heterogeneity in catchment response across the Cayuga Lake Watershed, ranging from 0.230 to 61.4. Variations in NO3‐N concentrations within each of the large synoptic sampling events were also high, ranging from 0.040 to 8.7 mg NO3‐N/l (March) and 0.090 to 15.5 mg NO3‐N/l (October). Although Pearson correlation coefficients suggest that this variability is related to multiple landscape factors during all four sampling events, partial correlations suggest percentage of row crops in the catchments as the only similar factor in March and October and catchment area as the only factor during summer low flows. Further, the strength of the relationships is typically lower in the HSAs of catchment. Advancing current understanding of such variations and relationships to landscape factors across multiple catchments – and under a variety of biogeochemical and hydrological conditions – is important, as (1) nitrate continues to be employed as an indicator of regional aquatic ecosystem health and services and (2) a unified framework approach for understanding individual catchment processes is a rapidly evolving focus for catchment‐based science and management. 相似文献
114.
转Bt基因棉花抗虫萜烯类化合物时空动态的HPLC分析 总被引:14,自引:0,他引:14
利用高效液相色谱(HPLC)技术对转Bt基因棉花抗虫萜烯化合物种类、含量以及时空动态进行了初步研究。结果表明,被研究的抗虫棉品种抗虫萜烯类化合物在不同品种、不同组织器官间含量差异较大。叶片中杀实夜蛾素(包括H1、H2、H3、H4)含量较高,花及蕾中棉酚含量的比例明显高于叶片。总抗虫萜烯类(包括棉酚、半棉酚酮、杀实夜蛾素H1、H2、H3、H4以及甲氧基半棉酚酮等)均以铃、顶叶含量最高,蕾、花柱等器官次之。说明在棉花不同品种、同一品种不同器官中是不同的萜烯类化合物在起到抗虫作用。图3参16 相似文献
115.
Ambient particles vary greatly in their ability to affect visibility, climate and human health. The fine fraction of aerosol
is responsible for greater and wider effects on human health; thus, investigation of this fraction is very important. Continuous
measurements of PM2.5 (particulate matter below 2.5 μm in size) concentrations at the Preila monitoring station started in
2003. During a period of 2 years, the episodes of high daily and semi-hourly concentrations of PM2.5 were measured. These
episodes did not depend on the season or time of day. The substantial role of long-range transport of pollutants to these
increases in concentration was shown using chemical and statistical analysis. It was found that most of the severe episodes
occurred when air masses came from a specific site besides it was established that air masses of different origin were characterized
by different mixing layer depth. Lower mixing depth was observed in air masses characterized by higher observed concentrations
at the measuring site and vice versa. PM2.5 concentrations showed diurnal and seasonal variations whose pattern reflected
the regional origin of the aerosol. The regional pollution level was evaluated by the statistical analysis of PM2.5 concentrations.
The background annual average of PM2.5 mass concentration for the eastern coast of the Baltic Sea was 15.1 ± 0.8 μg m−3. 相似文献
116.
7Be是研究大气科学与地球化学的核元素之一,对研究短期过程的地表土壤颗粒迁移具有较大价值。为了解南京地区利用7Be进行土壤侵蚀示踪研究的合适时机,于2010年1月~2011年12月收集南京地区各月的7Be沉降样品,经实验室化学实验处理和γ谱仪测量,计算7Be沉降通量,并分析7Be大气沉降的季节性变化趋势。结果表明:南京地区平均7Be沉降量为1 62178 Bq/(m2·a),沉降通量为066~1449 Bq/(m2·d),平均沉降通量为444 Bq/(m2·d);7Be沉降通量的季节变化呈现双峰型趋势,冬末春初和夏季是两个高值区;7Be沉降的а值冬春季较大,夏季最低;降雨量大小与沉降量存在明显的正相关 相似文献
117.
可持续发展水平时空解构表明,木垒县可持续发展能力很弱,资源问题成为限制其经济发展、社会发展及环境保护的主要因素。近8年来,木垒县可持续发展水平虽然呈良性上升状态,但其上升主要归功于社会发展因素,经济发展指数、资源指数等对其上升的推动性并不强。仅以提高经济发展水平为目的的掠夺式开发,使得资源匮乏的木垒县因此出现较为严重的资源性环境问题,并制约经济水平的提高。上述分析表明,资源指数成为新疆北疆地区少数民族贫困县可持续发展的基础,少数民族贫困县的贫困现状与其可持续发展能力弱是密切联系的。消除贫困的前提条件是实现可持续发展,因此,提高新疆少数民族贫困县的可持续发展水平这项任务迫切而重要。 相似文献
118.
Salgado R Marques R Noronha JP Mexia JT Carvalho G Oehmen A Reis MA 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2359-2367
An intensive sampling campaign has been carried out in a municipal wastewater treatment plant (WWTP) to assess the dynamics of the influent pharmaceutical active compounds (PhAC) and musks. The mass loadings of these compounds in wastewater influents displayed contrasting diurnal variations depending on the compound. The musks and some groups of PhACs tended to follow a similar diurnal trend as compared to macropollutants, while the majority of PhACs followed either the opposite trend or no repeatable trend. The total musk loading to the WWTP was 0.74 ± 0.25 g d−1, whereas the total PhAC mass loading was 84.7 ± 63.8 g d−1. Unlike the PhACs, the musks displayed a high repeatability from one sampling day to the next. The range of PhAC loadings in the influent to WWTPs can vary several orders of magnitude from one day or week to the next, representing a challenge in obtaining data for steady-state modelling purposes. 相似文献
119.
Temporal atmospheric temperature changes during summers at sub-Arctic sites often cause periodic fluctuations in shallow landfarm and surface soil temperatures. However, little information is available on the effect of site-relevant variations on biodegradation performance in cold climates. This study compares the rate and extents of biodegradation of petroleum hydrocarbons at variable site temperatures (1-10 °C) representative of summers at a sub-Arctic site reported previously with those obtained under a constant average temperature of 6 °C. The biodegradation was evaluated in pilot-scale landfarming experiments with field-aged petroleum-contaminated soils shipped from Resolution Island (61°30′N, 65°00′W), Nunavut, Canada. Under the variable site temperature conditions biodegradation rate constants of semi- (F2) and non-volatile (F3) hydrocarbon fractions were enhanced by over a factor of two during the 60-d experiment, compared to the constant temperature mode. The decrease in total petroleum hydrocarbons (TPH) under the variable site temperature mode was 55% compared to only 19% under the constant average temperature mode. The enhanced biodegradation is attributable to the non-linear acceleration of microbial activity between 4.7 and 10 °C and faster growth of indigenous hydrocarbon-degrading microbial populations. The first-order biodegradation rate constants of 0.018, 0.024 and 0.016 d−1 for TPH, F2 and F3 fractions at the variable site temperature were in agreement with those determined by an on-site experiment at the same site. 相似文献
120.
基于百度指数数据,运用指数测度、空间地理分析、回归模型和地理探测器,对2011—2019年中国大陆26个代表性滑雪场网络关注度的时空演变特征及影响因素进行分析。结果表明:(1)时间演化上,网络关注度呈先增后减且逐渐平稳的规律。2015年、2016年为峰值年份,季节性差异明显,共两个波动峰值且为“南北为单,中东为双”的分布格局。(2)空间特性上,全国和地区均为先增后减特征,地区差异显著;变异程度先降后增并趋于稳定,全国分布相对稳定平衡,地区分布呈不稳定集聚特性。省区冷热区域分布总体呈“东北热—西南冷”格局,层级变化以稳定型为主。(3)滑雪场层面上,滑雪场总体偏好层级变动较大,高偏好保持稳定领先,其余层级以下降变动为主。滑雪场冷热点分级呈“北热南冷”的格局,东北、华北两个热点集聚区域演变较为稳定。(4)影响因素上,需求侧影响因素排序为滑雪消费吸引力>受教育程度>经济发展水平>信息化水平>滑雪场建设水平。供给侧的滑雪人次占比、滑雪经济贡献、客运承载力、冰雪旅游资源丰度、官方媒体建设水平解释力较强,其他因素影响并不显著。 相似文献