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排序方式: 共有351条查询结果,搜索用时 11 毫秒
111.
This study performs a field analysis of the diffusion collection rate coefficients of radial geometry passive samplers to measure NO2 in a Mediterranean coastal area. The study shows that the collection rate coefficients are not constant and depend on certain environmental parameters as well as on the levels of some co-pollutants. A mathematical model, which explains the variation of the collection rate coefficient, has been established. 相似文献
112.
Li CR Lee SH Kim SS Kim A Lee KW Lu M Kim HE Kwak IJ Lee YJ Kim DK Lee JS Kang SW Huh MD Chung KH Park JS 《Environmental monitoring and assessment》2009,150(1-4):397-404
Serum vitellogenin (VTG) contents of wild goldfish (Carassius auratus) were investigated as a sensitive biomarker for artificial estrogenic compounds in aquatic environments. Goldfish was sampled from a pristine area, a river situated 5 km downstream from a sewage treatment works (STW), and also from the Young-San River in Korea. The female yolk precursor protein VTG was not detected when gonadosomatic index (GSI) was less than 0.85%, while VTG levels of >10 microg/ml were found in males whose GSI was less than 1.53%. In male goldfish sampled from STW and the Young-San River, the higher VTG corresponded to lower GSI. This study suggested a trend that gonad development was connected to VTG levels in both sexes, and the application of GSI and histological analysis provide an attractive possibility that it could be included in the panel of markers used for estrogenic activity investigation of aquatic environments. 相似文献
113.
Miao-Ching Cheng Chen-Feng You Fei-Jan Lin Chuan-Hsiung Chung Kuo-Fang Huang 《Atmospheric environment (Oxford, England : 1994)》2010,44(28):3386-3393
We investigated chemical and Sr isotopic composition of monthly rainwater collected on Peng-Chia-Yu (PCY) in northern Taiwan. Rainwater 87Sr/86Sr ratios, Na/Cl, Ca/Cl, Sr/Cl, Sr/Ca, NH4/Cl, NO3/Cl, SO4/Cl and Na/Sr, showed clear seasonal cycles, reflecting mixture of loess carbonates (high Ca/Sr and more radiogenic 87Sr/86Sr) and seawater (low Ca/Sr and intermediate 87Sr/86Sr). Model results showed that the former source contributes up to 45% during the winter monsoon period, but seawater is the dominant Sr source in rainwater (>50%) at other times. Two anomalously low 87Sr/86Sr values occurred in July and August 1998, coinciding with the Merapi eruption in Indonesia. Air-mass backward trajectories and the geochemical and isotopic compositions in rainwater and Merapi lava (i.e. Ca/Sr = 100 and 87Sr/86Sr = 0.705400) suggested that the Merapi eruption delivered ash across the western equatorial Pacific to PCY. Aerosols leaching experiments were conducted to examine the impact of the 1998 eruption, demonstrating that only a minor terrestrial signature can be extracted by distilled water, implying rapid dispatch of volcanic gases or high-efficiency dissolution of ash related substance in acidic rains. 相似文献
114.
This study investigated Taiwan's industries to identify the characteristics of companies most advanced in environmental design. Thirty design principles in five categories were used to define advanced environmental design. The five categories are: use of raw materials, use of energy, design for recyclability, product life cycle assessment, and packaging optimization. We found that of the 30 design principles only eight were applied consistently by Taiwanese manufacturers. Most effort was given to the “use of energy” category. The most advanced environmental design was found at large companies—those with over 2000 employees, 3 billion in capital, and/or 3 billion in annual sales. 相似文献
115.
Parental allocation strategies are of profound interest in life history because they directly impact offspring fitness and therefore are highly valuable for understanding population dynamics and informing management decisions. Yet, numerous questions about reproductive allocation patterns for wild populations of large mammals remain unanswered because of the challenges for measuring allocation in the wild. Using a nine-year longitudinal data set on life-history traits of mother-calf bison pairs, we identified sources of variation in relative maternal allocation (calf mass ratio on mother mass) and assessed the occurrence of reproductive costs associated with differential maternal allocation. We found that heavy mothers provided a lower allocation but still produced heavier calves than light mothers. Older females produced lighter calves and tended to decrease allocation as they aged, supporting the occurrence of reproductive senescence. Mothers that had produced a calf the previous year produced lighter calves and allocated less than mothers that did not lactate the previous year, revealing reproductive costs. However, greater maternal allocation did not reduce the probability of breeding in successive years, and the amount of allocation provided by a mother was positively correlated among the offspring she produced, illustrating individual heterogeneity. Although life-history studies are usually classified as either supporting costs of reproduction or individual quality, our study demonstrates that these contrasting evolutionary forces can shape variation within a single trait. Our work illustrates that many processes can coevolve within a population, emphasizing the need to integrate multiple concepts to better understand the evolution of life-history traits. With regard to management of bison herds, if the goal of culling programs is to select for animals with the best performance, this research suggests that managers should account for the condition and previous reproductive status of mothers when taking culling decisions on juvenile bison. 相似文献
116.
117.
This study examines the motivations of mainland Chinese facilities in seeking ISO 14001 certification and examines the linkages between these motivations and self-reports of the effectiveness of major environmental management system (EMS) components. In a sample of 128 facilities in Beijing, Shanghai, and Guangzhou, the main drivers for certification were reported to be to ensure regulatory compliance, to enhance the firms reputation, and to improve environmental performance, in that order. Although motivation to achieve cost reductions were least emphasized, a broad range of motivations appears to be considered in the decision to seek certification to ISO 14001. Regression models linking these motivations to the EMS components suggests that internal motivations have an influence on most EMS components. One interesting exception to this, however, is that no significant relationship was observed between internal motivations and the promulgation of environmental objectives and targets. The relationships associated with external motivations for certification (i.e., those in response to customer and other stakeholder pressures) and EMS components, on the other hand, are weaker and tend to occur earlier in the process cycle. No significant relationships were found between motivations to reduce costs and perceptions of the effectiveness of EMS components. Overall, these findings suggest that ISO 14001, as currently being implemented in mainland China, may have a modestly useful role when used in combination with other policy mechanisms to move the Chinese economy toward more sustainable practices. It is asserted that the ISO standard could provide even greater benefits if Chinese registrars were more proactive in developing EMS in conjunction with even more rigorous third-party audits.Published online 相似文献
118.
During the dry season in Korea, rivers become more vulnerable to contamination by biochemical oxygen demand (BOD) and nitrogen. It is hypothesized that the natural characteristics of the streams in Korea allow the contaminated water to be treated at the tributaries. Down-stream river water quality in Korea may be improved by spraying the contaminated stream water from the tributaries over the surrounding floodplains. The consequent water filtration through the soil could remove the contaminants through aerobic and denitrifying reactions. In this study, the kinetics parameters of the denitrifying reaction in floodplain filtration were determined using contaminated stream water. For the electron donor the Monod kinetics was used, while the competitive Michaelis-Menten model was employed for the electron acceptors. The parameters to the competitive Michaelis-Menten model were found using continuous denitrifying reactions, instead of the batch reactions employed in previous studies, to match the conditions needed to apply the competitive Michaelis-Menten kinetics. From the result, it was found that continuous reactions as well as batch reactions could be used to determine the affinity coefficients in denitrification. The results of this study also showed that the affinity coefficient of NO2, using continuous reactions, was similar to that of other studies in the literature found via batch reactions, whereas the affinity coefficient of N2O was much larger than that acquired with batch reactions. The parameters obtained in this study will be used in future work to simulate the contaminant behaviors during floodplain filtration using a mathematical model. 相似文献
119.
Chung Y. S. Kim H. S. Park K. H. Jhun J. G. Chen S. J. 《Water, Air, & Soil Pollution: Focus》2003,3(2):21-40
This Korea-China study monitored the phenomena of sandstorms and significant dustfall (SD) from 1997 to 2000. The analysis of our data included ground measurements of dust concentration, visibility, satellite imagery, aircraft and lidar observations. In addition, an estimation of atmospheric loadings and a studyon the relationship between dust concentrations and visibilitywere carried out. The movement and invasion of dust clouds toKorea were clearly identified with meteorological and satellitedata. The increasing concentrations of TSP and PM10 concurredwell with the satellite information. From case studies, weestimated that atmospheric loadings of a dust cloud were over 1million ton and that the deposition over the Korean Peninsulawas in the range from 46 000 to 86 000 tons. For SD withvisibility of 3 km, we predict TSP 659 g m-3 and PM10 493 g m-3. We recommend the issuance of an SD Watch(advisory) and an SD Warning for the general public. 相似文献
120.
The National Vegetation Classification Standard (NVCS) was implemented at two US National Park Service (NPS) sites in Texas,
the Padre Island National Seashore (PINS) and the Lake Meredith National Recreation Area (LMNRA), to provide information for
NPS oil and gas management plans. Because NVCS landcover classifications did not exist for these two areas prior to this study,
we created landcover classes, through intensive ground and aerial reconnaissance, that characterized the general landscape
features and at the same time complied with NVCS guidelines. The created landcover classes were useful for the resource management
and were conducive to classification with optical remote sensing systems, such as the Landsat Thematic Mapper (TM). In the
LMNRA, topographic elevation data were added to the TM data to reduce confusion between cliff, high plains, and forest classes.
Classification accuracies (kappa statistics) of 89.9% (0.89) and 88.2% (0.87) in PINS and LMNRA, respectively, verified that
the two NPS landholdings were adequately mapped with TM data. Improved sensor systems with higher spectral and spatial resolutions
will ultimately refine the broad classes defined in this classification; however, the landcover classifications created in
this study have already provided valuable information for the management of both NPS lands. Habitat information provided by
the classifications has aided in the placement of inventory and monitoring plots, has assisted oil and gas operators by providing
information on sensitive habitats, and has allowed park managers to better use resources when fighting wildland fires and
in protecting visitors and the infrastructure of NPS lands. 相似文献