首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   83篇
  免费   1篇
  国内免费   1篇
安全科学   4篇
废物处理   6篇
环保管理   5篇
综合类   3篇
基础理论   15篇
污染及防治   27篇
评价与监测   22篇
社会与环境   3篇
  2023年   3篇
  2022年   6篇
  2021年   6篇
  2020年   1篇
  2019年   3篇
  2018年   3篇
  2017年   4篇
  2016年   4篇
  2015年   6篇
  2014年   8篇
  2013年   16篇
  2010年   6篇
  2009年   4篇
  2008年   6篇
  2007年   4篇
  2006年   3篇
  2003年   1篇
  2000年   1篇
排序方式: 共有85条查询结果,搜索用时 93 毫秒
21.
This research was carried out in the cities of Zonguldak and Eregli, which have been characterized as urban and industrial environments of the Western Black Sea Region, Turkey, in order to assess the contamination of polycyclic aromatic hydrocarbons (PAHs) using mosses as biomonitors. The methodology involved the collection of moss samples (Hypnum cupressiforme), ultrasonic extraction with dichloromethane, cleanup using silica gel and analysis by liquid chromatography with ultraviolet detection. The total PAH concentrations ranged from 78.1 to 1693.5 ng g?1 in Zonguldak and from 15.2 to 275.1 ng g?1 in Eregli. The total PAH concentration in Eregli was about six times lower than that in Zonguldak, revealing the importance of switching from coal to natural gas in residential heating. The diagnostic ratios and the correlation analysis have indicated that coal combustion and traffic emissions were the major PAH sources at both sites. The contour maps were constructed for the determination of spatial distributions of total PAHs, and it was shown for Zonguldak as well as for Eregli that the PAH pollution was much more predominant in highly populated regions. Moving away from the city centres, a gradual decrease in PAH pollution rates was observed.  相似文献   
22.
Most species face multiple anthropogenic disruptions. Few studies have quantified the cumulative influence of multiple threats on species of conservation concern, and far fewer have quantified the potential relative value of multiple conservation interventions in light of these threats. We linked spatial distribution and population viability models to explore conservation interventions under projected climate change, urbanization, and changes in fire regime on a long‐lived obligate seeding plant species sensitive to high fire frequencies, a dominant plant functional type in many fire‐prone ecosystems, including the biodiversity hotspots of Mediterranean‐type ecosystems. First, we investigated the relative risk of population decline for plant populations in landscapes with and without land protection under an existing habitat conservation plan. Second, we modeled the effectiveness of relocating both seedlings and seeds from a large patch with predicted declines in habitat area to 2 unoccupied recipient patches with increasing habitat area under 2 projected climate change scenarios. Finally, we modeled 8 fire return intervals (FRIs) approximating the outcomes of different management strategies that effectively control fire frequency. Invariably, long‐lived obligate seeding populations remained viable only when FRIs were maintained at or above a minimum level. Land conservation and seedling relocation efforts lessened the impact of climate change and land‐use change on obligate seeding populations to differing degrees depending on the climate change scenario, but neither of these efforts was as generally effective as frequent translocation of seeds. While none of the modeled strategies fully compensated for the effects of land‐use and climate change, an integrative approach managing multiple threats may diminish population declines for species in complex landscapes. Conservation plans designed to mitigate the impacts of a single threat are likely to fail if additional threats are ignored. Manejo de Incendios, Reubicación Administrada y Opciones de Conservación de Suelo para Plantas de Vida Larga con Sembrado Obligado bajo los Cambios Globales en el Clima, la Urbanización y el Régimen de Incendios  相似文献   
23.
This study analyses forest dynamics and land use/land cover change over a 43-year period using spatial-stand-type maps of temporal forest management plans of Karaisal? Forest Enterprise in the Eastern Mediterranean Region of Turkey. Stand parameters (tree species, crown closures and developmental stages) of the dynamics and changes caused by natural or artificial intervention were introduced and mapped in a Geographic Information System (GIS) and subjected to fragmentation analysis using FRAGSTATS. The Karaisal? Forest Enterprise was first planned in 1969 and then the study area was planned under the Mediterranean Forest Use project in 1991 and five-term forest management plans were made. In this study, we analysed only four periods (excluding 1982 revision plans): 1969, 1991, 2002 and 2012. Between 1969 and 2012, overall changes included a net increase of 3,026 ha in forested areas. Cumulative forest improvement accounted for 2.12 % and the annual rate of total forest improvement averaged 0.08 %. In addition, productive forest areas increased from 36,174 to 70,205 ha between 1969 and 2012. This translates into an average annual productive forest improvement rate of 1.54 %. At the same time, fully covered forest areas with crown closure of “3” (>70 %) increased about 21,321 ha, and young forest areas in developmental stage of “a” (diameter at breast height (dbh)?<?8 cm) increased from 716 to 13,305 ha over the 43-year study period. Overall changes show that productive and fully covered forest areas have increased egregiously with a focus on regenerated and young developmental stages. A spatial analysis of metrics over the 43-year study period indicated a more fragmented landscape resulting in a susceptible forest to harsh disturbances.  相似文献   
24.
There is an increasing attempt in the world to determine the exposures of children to environmental chemicals. To analyze the genotoxic effect of air pollution, micronucleus (MN) assay was carried out in buccal epithelial cells (BECs) of children living in an urban city of Turkey. Children from two schools at urban-traffic and suburban sites were investigated in summer and winter seasons for the determination of BEC-MN frequency (per mille) and frequency of BEC with MN (per mille). The same children were also recruited for lung function measurements within a MATRA project (“Together Towards Clean Air in Eskisehir and Iskenderun”) Measured NO2 and SO2 concentrations did not exceed the European Union (EU) limit levels either in urban-traffic or suburban regions. Higher O3 concentrations were measured in the suburban site especially in the summer period. Particulate matter (PM2.5 and PM10) levels which did not differ statistically between two regions were above the EU limits in general. Although BEC-MN frequencies of children living in the suburban sites were higher in general, the difference between two regions was not significant either in the summer or winter periods. BEC-MN frequencies of the urban-traffic children were found to be significantly higher in summer period (mean ± SD, 2.68?±?1.99) when compared to winter period (1.64?±?1.59; p?=?0.004). On the other hand, no seasonality was observed for the suburban children. Similar results have been obtained in the BEC frequency with MN in our study. In summer, BEC-MN frequencies were significantly increased with the decrease in pulmonary function levels based on forced expiratory flow between 25 and 75 % of vital capacity (FEF25–75 %) levels (p?<?0.05). As a conclusion, children living in urban-traffic and suburban areas in the city of Eski?ehir exhibited similar genotoxicity. Seasonal variation in genotoxicity may be interpreted as relatively high ozone levels and increasing time spent at outdoors in the summer.  相似文献   
25.
Abstract: Disruption of gene flow among demes after landscape fragmentation can facilitate local adaptation but increase the effect of genetic drift and inbreeding. The joint effects of these conflicting forces on the mean fitness of individuals in a population are unknown. Through simulations, we explored the effect of increased isolation on the evolution of genetic load over the short and long term when fitness depends in part on local adaptation. We ignored genetic effects on demography. We modeled complex genomes, where a subset of the loci were under divergent selection in different localities. When a fraction of the loci were under heterogeneous selection, isolation increased mean fitness in larger demes made up of hundreds of individuals because of improved local adaptation. In smaller demes of tens of individuals, increased isolation improved local adaptation very little and reduced overall fitness. Short‐term improvement of mean fitness after fragmentation may not be indicative of the long‐term evolution of fitness. Whatever the deme size and potential for local adaptation, migration of one or two individuals per generation minimized the genetic load in general. The slow dynamics of mean fitness following fragmentation suggests that conservation measures should be implemented before the consequences of isolation on the genetic load become of concern.  相似文献   
26.
In this research, in order to determine mean fungus counts, indoor and outdoor air samples were taken in five elementary school buildings located in the city center of Seferihisar, Izmir (45 km from Izmir) within a 1-year period between March and April 2004, and between January and February 2005 representing similar climatic characteristics. Five samples, three from three classes where 5–8, 10–12, and 12–15 age group students attended, one from the corridors, and one from outside the buildings in all the schools, were taken for each period. Within the period of the study, in indoor and outdoor air samples, 7,122 microfungus colonies were counted. Sixty-four species were identified that belong to 17 genera as a result of the identification of isolates obtained. Skin prick tests were applied to 55 out of a total of 117 teachers by the clinicians. According to these test results, 24 teachers were sensitive to at least one agent. Results revealed that, in terms of mold counts, the difference between the schools and the difference between the times (periods) were statistically significant (p?< 0.05).  相似文献   
27.
In this study, surface water quality of the Ceyhan River basin were assessed and examined with 13 physico-chemical parameters in 31 stations in 3 months during the period of 2005. Multivariate statistical techniques were applied to identify characteristics of the water quality in the studied stations. Nutrients, Cl??? and Na?+? affected mostly to the stations of Erkenez 2, S?r 2, and S?r 3 in the ordination diagram of correspondence analysis. Three factors were extracted by principal component analysis, which explains 79.14% of the total variation. The first factor (PC1) captures variables of EC, DO, NO $_{2}^{\; -}$ , PO $_{4}^{\; \equiv }$ , Cl???, SO $_{4}^{\; =}$ , Na?+?, and Ca?+?+?. The second factor (PC2) is significantly related to pH, NH $_{3}^{\; -}$ , and Mg?+?+?, while water temperature (T) and NO $_{3}^{\; -}$ accounted for the greatest loading for factor 3 (PC3). The stations were divided into three groups for PC1, two groups for PC2, and three groups for PC3 by hierarchical cluster analysis. The stations in the vicinity of cities presented low dissolved oxygen and high concentration of physico-chemical parameter levels. The stations of Erkenez 2, S?r 2, S?r 3, and Aksu 4 located near the city of Kahramanmara? were characterized by an extremely high pollution due to discharge of wastewater from industry and domestic. P?narba?? and Elbistan stations were also influenced by household wastewater of the city of Elbistan. According to criteria of Turkish Water Pollution Control Regulation, Erkenez 2, S?r 2, and S?r 3 stations have high polluted water. This study suggests that it is urgent to control point pollutions, and all wastewater should be purified before discharge to the Ceyhan River basin.  相似文献   
28.
The aim of this study was to determine if high concentrations of any heavy metals exist in the sediment of Seyhan Dam reservoir to be considered toxic to the aquatic environment. Surface sediment samples from five stations in the Seyhan dam were collected quarterly from 2004 to 2005 and examined for metal content (Cr, Zn Cu, Mn, Cd, Fe, Ca, K, and Na), organic matter, and grain size. Correlation analyses showed that metal content of Seyhan dam sediment was affected by organic matter and grain size. The results have been compared with values given in the literature. The evaluation of the metal pollution status of the dam was carried out by using the enrichment factor and the geoaccumulation index. A comparison with sediment quality guideline values has also been made. Based on the enrichment factor, dam sediments were treated as a moderately severe enrichment with Cd and minor enrichment with Cr and Mn. The results of geoaccumulation index reveal that sediments of Seyhan Dam were strongly polluted in stations 1, 2, 4, and 5, and were moderately polluted in station 3 with Cd. Moreover, Cd and Cr concentrations in the sediments were above TECs except ERL for Cd.  相似文献   
29.
30.
The purpose of the study was the experimental evaluation of ultrafiltration as a potential innovative technology for the removal of organic matter of around 15,000 mg chemical oxygen demand (COD) per liter in the polymer industry wastewater. Particle size distribution (PSD) analysis served as the major experimental instrument along with conventional chemical settling. Biodegradation characteristics of the remaining COD after ultrafiltration were determined by model interpretation of the corresponding oxygen uptake rate (OUR) profile. The study first involved a detailed characterization of the polymer wastewater including PSD analysis of the COD content. Chemical treatability was investigated using lime alone and with ferric chloride as coagulants followed with a PSD assessment of the chemically settled effluent. Modeling of the OUR profile generated by the ultrafiltration effluent defined related biodegradation kinetics and provided information on the overall COD removal potential. PSD analysis indicated that more than 70 % of the total COD accumulated in the 220- to 450-nm size range. It indicated that ultrafiltration was potentially capable of removing more than 90 % of the COD with an effluent lower than 1,500 mg COD/L. Chemical settling with 750 mg/L of FeCl3 dosing at a pH of 7.0 provided a similar performance. The ultrafiltration effluent included mainly hydrolysable COD and proved to be biodegradable, with the process kinetics compatible with domestic sewage. PSD evaluation proved to be a valuable scientific instrument for underlining the merit of ultrafiltration as the appropriate innovative technology for polymer wastewater, removing the major portion of the COD in a way that is suitable for recovery and reuse and producing a totally biodegradable effluent.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号