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231.
232.
Kostanjsek R Lapanje A Drobne D Perović S Perović A Zidar P Strus J Hollert H Karaman G 《Environmental science and pollution research international》2005,12(6):361-368
- Goal, Scope, Background. Lake Skadar is the largest lake in Balkan Peninsula, located on the Montenegro-Albanian border. The
unique features of the lake and wide range of endemic and rare or endangered plant and animal species resulted in the classification
of the Skadar as a wetland site of international significance. In spite of its importance the Lake is influenced by inflowing
waters from river Morača and other regional rivers contaminated by the industry, municipal and agricultural activities in
the area. Therefore, the Lake has been subject of various physical, chemical, biological and toxicological examinations. However,
community-level analyses are most relevant to assess the effect of stressors on aquatic ecosystems. In the present study bacterial
community structure among differently polluted sites of the lake was compared by genetic fingerprinting technique.
Methods Water and sediment samples were collected from five differently polluted sampling sites on the Lake Skadar in spring and
autumn of the same year. The bacterial community structure in the samples was characterized and compared by temporal temperature
gel electrophoresis (TTGE) analysis of polymerase chain reaction-amplified bacterial 16S rRNA genes.
Results and Discussion The TTGE analysis resulted in many distinguishable and reproducible band patterns, allowing reliable comparison of bacterial
communities among sampling sites. Results on the bacterial community structure revealed that three of the selected locations
can be considered as sites that have not shown any pollution degradation determined by our method, due to similar structure
of bacterial community in the sediment samples. On the other hand, significant shifts in bacterial community structure in
the mouth of the river Morača and Plavnica were shown. Since the results coincide with some of the bioassays and chemical
analysis performed previously, the changes in bacterial community structure are explained as an effect of antropogenic pollution
on the lake ecosystem by waters of river Morača and stream Plavnica.
Conclusion The TTGE has proven to be an efficient and reliable method to monitor bacterial dynamics and community shifts in aquatic
environment, especially in the sediments. Within the variety of environmental quality assessments the use of TTGE analyses
of bacterial community is strongly recommended, particularly as an initial investigation. However, in any conclusion on the
state of the environment, the TTGE results should be combined to some other biological, chemical and hydrological data.
Recommendation and Outlook Since prokaryotes are a crucial group of organisms in the biosphere, the ecosystem function studies are largely based on
bacterial communities. Therefore, bacterial community structure analysis should be a part of an integrated weight of evidence
approach in pollution assessment. In case of Triad approach, consisting of chemical analyses, bioassays, and community studies
in the field, the TTGE bacterial community structure analyses should be placed in the later Triad leg. In comparison to other
community studies, based on various biotic indices, the TTGE bacterial community analysis has proven to be very sensitive,
reliable and less time consuming. 相似文献
233.
Past dioxin (coplanar polychlorinated biphenyl (Co-PCB), 2,3,7,8-substituted polychlorinated dibenzo-p-dioxin (PCDD) and 2,3,7,8-substituted polychlorinated dibenzofuran (PCDF)) fluxes recorded in dated aquatic-sediment cores were analyzed using principal component analysis (PCA). The data set consisted of samples from four cores collected from the Kanto region of Japan. Time trends and spatial differences in the dioxin flux were examined, and the potential relationship to emission sources was investigated. Twenty-five compounds and 58 core slices, corresponding to the later half of the 20th century, were subjected to the analysis. The PCA of both log-transformed and maximum-value-standardized data successfully divided the dioxin compounds into a small number of groups, and three similar clusters of Co-PCBs, PCDDs and penta- to hepta-CDFs were identified. PCB formulations used in the past are judged to have been responsible for the major part of the Co-PCB flux recorded in the sediment cores. However, the relationship to emission sources needs further investigation. It is suggested that most 2,3,7,8-substituted PCDDs and PCDFs are different from Co-PCBs in their emission sources or movements in the environment. The subcore clusters obtained from the PCA of log-transformed data show that the cores from different sampling areas exhibited distinct dioxin fluxes and compositions. Common time trends among the cores were more effectively summarized by the PCA of maximum-value-standardized data focusing on relative time trends. PC scores show that recently the flux of each dioxin compound in the four cores has been generally declining after having reached a peak. 相似文献
234.
水污染是困扰淮阴区工农业发展的问题之一。因此对盐河淮阴区段近几年来的水质状况进行了评价,分析了水体污染形成的原因及发展趋势,阐述了污染特征和程度,并提出了改善水环境的对策。 相似文献
235.
Nenad Aleksic Garry Boynton Gopal Sistla Jacqueline Perry 《Atmospheric environment (Oxford, England : 1994)》2005,39(40):7894-7905
Since 1990s, a systematic program to measure air toxics has been active in New York State with monitors located both in urban and rural areas. In this study we examined the spatial and temporal characteristics of benzene, a known human carcinogen that is emitted by many source categories. The analysis indicates that ambient concentration levels of benzene have decreased by as much as 60% over this period not only in the ozone non-attainment area of New York City that had the reformulated gas (RFG) requirements, but also over the rest of the state as well. Although the rate of decrease appears to have flattened out in recent years, the annual average concentration levels are found to be above the health risk threshold even at the remote location, Whiteface Mountain, suggesting the need for further reductions in benzene emissions. 相似文献
236.
利用最新的AIRS卫星观测资料分析了2002年12月~2016年11月全球和东亚地区(70°~140°E,10°~55°N)CH4浓度的时空变化分布特征.研究发现,2003~2016年,全球CH4年平均浓度从1774.2×10-9增加到1789.1×10-9,年增长率约为1.1×10-9/a;东亚地区CH4年平均浓度从1811.5×10-9增加到1841.0×10-9,年增长率约为2.0×10-9/a.在美国西南部、南美洲南部、澳大利亚东南部、中国青藏高原和东北地区等地上空,CH4浓度增幅比较明显,而在北美洲的东北部上空,CH4浓度出现负增长.北美洲东北部和俄罗斯东部等地上空CH4浓度的变化与温度变化呈正相关;如在冬季,该地区温度与周围地区相比更低,同时CH4浓度更低.本文利用近10a的卫星数据获得了CH4浓度的垂直廓线,显示不同纬度带CH4浓度均随着高度的升高逐渐减小,且高纬度地区CH4浓度减小的最快.近年来,在低纬度地区对流层中低层CH4浓度变化较为明显.在对流层低层(850hPa),北半球CH4浓度随着纬度增加逐渐变大;在南半球则随着纬度增加先减小后变大.而在平流层内,CH4浓度在赤道处最大,且随着纬度的升高逐渐减小.此外,CH4的浓度分布存在明显的季节变化:在北半球,大部分地区夏季CH4浓度高于冬季(约20×10-9~40×10-9),但在撒哈拉沙漠和中国新疆塔里木盆地等地区上空,冬季CH4浓度高于夏季(约40×10-9~60×10?9).在冬季,中国四川西部上空的CH4浓度要比青藏高原上空高(约100×10-9~120×10-9). 相似文献
237.
以南方林区为研究区域,基于林业统计年鉴和MODIS卫星火点数据,结合相关文献中不同林型各类污染物的排放因子数据,估算2000~2016年间研究区域各省森林生物质燃烧及污染物排放总量,并分析其时空变化情况.结果表明,南方林区森林火灾总体呈先升后降的趋势,林火空间分布较为分散.2000~2016年南方林区森林生物质燃烧总量4.79×104kt.其中,温带常绿针叶林、温带常绿阔叶林、温带落叶阔叶林、热带常绿阔叶林和灌木的燃烧比例分别为65.24%,17.45%,1.55%,1.10%和14.66%.CO、CO2、NOx、CH4、VOCs和PM2.5等主要污染物的排放总量均值依次为3.73×103,5.87×104,48.05,347.27,358.54和365.06kt.此外,各类污染物的时空分布差异性明显:福建、广东、广西全省,海南西部,以及江西和湖南南部是各类污染物网格排放高值区;江西和湖北各类污染物的排放呈显著下降,福建NOx、VOCs和PM2.5,以及广东CH4和VOCs下降趋势显著,其余省份各类污染物排放下降但不显著.林火释放污染物占工业粉尘比例呈波动性上升,表明该地区森林火灾对大气环境的影响程度逐渐增加. 相似文献
238.
为研究渭南市区2014?—?2016年的冬春季雾霾天气的特点,选取覆盖渭南市区的4个监测站点,分析渭南市区PM_(10)和PM_(2.5)污染时间分布特征;同时选取日平均气温、相对湿度、风等气象因素,用线性回归分析法分析各个气象因素同大气中PM_(10)和PM_(2.5)的相互关系。研究发现:三年来冬季PM_(10)和PM_(2.5)的日变化的峰值主要出现在12月—?次年1月;春季PM_(10)和PM_(2.5)的逐日变化的峰值主要出现在3月;日内的周期变化趋势呈多次波动。渭南市区冬春PM_(10)和PM_(2.5)的质量浓度与风速、气温呈负相关,与相对湿度呈正相关,为雾霾的形成创造了条件,在冬季温度较高的情况下以及相对湿度较大的情况下应加强防范。在冬季12月—?次年1月和春季3月应注意雾霾的防范和治理,燃煤企业要安装脱硫脱硝装置,居民日常生活中尽量减少生物燃料的燃烧,同时政府应根据污染物排放量征税,用制度保护环境。 相似文献
239.
以辽河口为研究区域,利用遥感影像数据、现状调查数据和历史监测数据,系统地分析了辽河口沉积物质量历史变化趋势和空间分异规律,并进一步研究不同海域使用类型和不同植被演替阶段对沉积物环境要素分异特征的影响.结果表明,辽河口区域沉积物质量总体良好,各要素平均含量均符合一类沉积物质量要求;沉积物营养元素呈现显著的带状分布规律,重金属元素空间分布具有一定随机性,未呈现显著规律;不同海域使用类型对沉积物污染物富集的影响具有一定差异显著性,说明重金属及污染物的分布受到人类活动的影响,具有一定的随机性;植被不同演替阶段下主控因子具有显著差异,初级阶段主要受盐度控制,随着由盐生植被向陆生植被逐渐过渡,植被分布特征与总有机碳(TOC)、总氮(TN)和总磷(TP)的内在联系逐渐增大,同时重金属等污染物含量与植被群落内在联系并不显著. 相似文献
240.
论文以中国2003—2015年GRACE水储量数据、GLDAS-Noah地表蒸散发数据、地面实测降水数据为数据源,基于Theil-Sen Median 趋势分析和Mann-Kendall检验法,分析了中国水储量、降水量以及蒸散发量的变化趋势及相关关系,并利用经验正交函数(EOF)分析了中国水储量变化时空分布特征,结果表明:1) 2006年以后中国整体水储量年际变化剧烈,且降水和蒸散发可以识别水储量异常时段内的特征信息;2) 2003—2015年全国各地水储量、降雨量和蒸散发量变化空间分布差异明显;3) 全国共有18.6%的地区气候因素对水储量变化的方差解释量超过50%,主要位于中国东北、东南沿海、四川盆地、青海高原以及新疆西北部地区;4) EOF分解的GRACE水储量各主成分信息可以表征研究时段内中国地区整体和局部的水储量时空变化特征。 相似文献