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91.
The Danjiangkou reservoir lies in the upper Hanjiang basin and is the source of water for the Middle Route Project (MRP) under the South-to-North Water Transfer Scheme (SNWT) in China. The eco-environment of water resource areas plays an important role in water conservation and purification and would have significant implications for the economic prosperity in Hanjiang basin as well as for the SNWT. Focusing on the Danjiangkou Reservoir Area (DRA), this study established an environmental information system database. Based on the database, an eco-environmental vulnerability assessment method using integrated fuzzy AHP (FAHP) and GIS was developed for the DRA. According to eco-environmental conditions and anthropic effects, vulnerability was classified into five levels: potential, light, medium, heavy and very heavy. The eco-environmental vulnerability distribution and major problems of the eco-environment were analysed and discussed. The results indicated that eco-environmental vulnerability in the DRA was moderate overall. Regions with lower eco-environmental vulnerability were located in Qinling Mountain area in the northwest, Daba Mountain area in the south and the area immediately surrounding Danjiangkou Reservoir in the east. Two regions with very high eco-environmental vulnerability were located in the north of Danjiangkou Reservoir in Henan province and in the western part of Shanxi province. On the basis of analysis of distribution of the different factors of eco-environmental vulnerability, different environmental protection measures were proposed for different areas. This study demonstrated that the proposed method was an effective approach for the assessment of environmental vulnerability. The results gained closely reflected the reality of the eco-environmental vulnerability of the DRA.  相似文献   
92.
The volatile organic pollutants from direct vehicular exhaust were trapped with activated charcoal, desorbed with carbon disulphide and analysed by GC/MS with tert-butyl benzene as an internal standard. A comparative study was made from the exhaust of 1000 cc, 1300 cc, 1600 cc cars, pickup, lorry(diesel), 125 cc and 70 cc motorbikes. The level of pollutants emitted were in the following order, motorbike(petrol) car(petrol) pickup(petrol) lorry(diesel). The range of highest emission (125 cc motorbike) to the lowest emission (lorry(diesel)) was of the order of 102 for benzene, 6×102 for ethyl benzene, 5×102 for toluene and 3×102 for xylenes. Among cars, those fitted with catalytic convertors emitted a lower level of benzene (2 to 3 times) when compared with those without catalytic convertors. Similar studies on the air in air-conditioned buses, non air-conditioned buses and three metres from the edge of the road shows that they have the same pollutant level. The level of these pollutant as compared to those from direct car exhaust are of the order of 102 times less for benzene, xylene and toluene and 103 times less for ethylbenzene. The levels of benzene, toluene, ethylbenzene and xylenes by the road side and in the buses were found to be lower than the exposure limits of ACGIH, OSHA and EH40.  相似文献   
93.
We conducted a multicity time-series study using monitoring data to assess seasonal patterns of short-term ozone–mortality association among elderly aged 65 years and over in Japan. Daily exposure to ambient ozone was computed using hourly measurements of photochemical oxidants available at multiple monitoring stations in each city. Effects of ozone on daily all-cause non-accidental, cardiovascular, and respiratory mortality were estimated using distributed lag linear models, controlling for confounding by temporal, day of the week, temperature, and flu epidemics. City-level effect estimates were combined using inverse variance meta-analysis. In spring and autumn, a 10-ppbv increase of daily maximum 8-h average ozone concentration in the previous 3 days was associated with 0.69 % (95 % confidence interval (CI): 0.27–1.10), 1.07 % (0.34–1.82), and 1.77 % (0.78–2.77) increases in daily all-cause, cardiovascular, and respiratory mortality, respectively. Forward displacement of respiratory mortality was large during the cold season despite lower ozone concentration. Results were generally independent of fine particulate matter and nitrogen dioxide. Findings suggest significant mortality effects of short-term ozone exposure among the elderly during the moderate season. Those with underlying respiratory diseases were susceptible, even during winter.  相似文献   
94.
The aim of this work was to report on imidacloprid [IUPAC name 1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine] residues in some vegetables, fruits, and water samples collected from the West Bank, Palestine, in 1998 and 1999. Imidacloprid and its derivatives in the study samples were extracted by methanol/water and oxidized into 6-chloronicotinic acid and subsequently derivatized into 6-chloronicotinic acid trimethylsilyl ester before being determined by GC/MS. Imidacloprid residues were detected in more than half of the analyzed samples. The highest and lowest imidacloprid concentrations were found in eggplant (0.46 mg/kg) and green beans (0.08 mg/kg), respectively. An increase of 11–120% in imidacloprid concentration in the 1999 samples was observed when compared with those of 1998. This may suggest imidacloprid accumulation in the soil and/or increased use by local farmers. The imidacloprid residue concentrations in several crops were found to exceed the CODEX maximum residue limit.  相似文献   
95.
Variations in the relative contributions of gene flow and spatial and temporal variation in recruitment are considered the major determinants of population genetic structure in marine organisms. Such variation can be assessed through repeated measures of the genetic structure of a species over time. To test the relative importance of these two phenomena, temporal variation in genetic composition was measured in the limpet Cellana grata, among four annual cohorts over 10 years at four rocky shores in Hong Kong. A total of 408 limpets, comprising individuals from 1998, 1999, 2006 and 2007 cohorts were screened for genetic variation using five microsatellite loci. Minor but significant genetic differentiation was detected among samples from the 1998/1999 collection (F ST = 0.0023), but there was no significant differentiation among the 2006/2007 collection (F ST = 0.0008). Partitioning of genetic variation among shores was also significant in 1998/1999 but not in the 2006/2007 collection, although there was no correlation between genetic and geographic distances. There was no significant difference between collections made in 1998/1999 and 2006/2007. This lack of clear structure implies a high level of gene flow, but differentiation with time may be the result of stochastic recruitment variation among shores. Estimates of effective population size were not high (599, 95% C.L. 352–11397), suggesting the potential susceptibility of the populations to genetic drift, although a significant bottleneck effect was not detected. These findings indicate that genetic structuring between populations of C. grata in space and time may result from spatio-temporal variation in recruitment, but the potential development of biologically significant differentiation is suppressed by a lack of consistency in recruitment variability and high connectivity among shores.  相似文献   
96.
ABSTRACT: The hydrologic modeling of streamflow in the Waterford River Basin has been conducted as part of comprehensive investigations of the effects of urbanization on water resources in the basin. Using a detailed input data base, continuous simulation of streamflow in the study area has been done by means of the HSPF model, which has been calibrated for the existing conditions and then applied to several future land use scenarios. The basin climate and geology contribute to high conversion of precipitation into streamflow under the existing conditions. Consequently, future urban development in the study basin should not increase the annual streamflow, but would contribute to increases in peak flows and the incidence of flooding because of the increased speed of runoff. If the impervious area in the basin is doubled, the peak flows may increase by about 20 percent.  相似文献   
97.
Analyzing historical databases can provide valuable information on the incident occurrences and their consequences for assessing the safety of the chemical process industry. In this study, the RMP and HSEES databases were utilized to understand the patterns and the factors influencing chemical process industry incidents. Frequency exceedance curves were generated by utilizing the different incident consequences from the databases to understand the profile of societal loss from reported incidents. Understanding the statistics and trends of the historical incidents could serve as important lagging indicators in order to assess the probable proximity to major consequences from the low-probability/high-consequence incidents. To this regard, the safety pyramids were also generated to better understand the relationship between the different consequences of the reported incidents. Furthermore, the safety pyramids were analyzed in comparison with the traditional safety pyramid proposed by Heinrich to understand the US process industry incident occurrence trends.  相似文献   
98.
Extensive contamination of soils by highly recalcitrant contaminants such as polycyclic aromatic hydrocarbons (PAHs) is an environmental problem arising from rapid industrialisation. This work focusses on the remediation of soil contaminated with 3- and 4-aromatic ring PAHs (phenanthrene (PHE) and fluoranthene (FLUT)) through catalysed hydrogen peroxide propagation (CHP). In the present work, the operating parameters of the CHP treatment in packed soil column was optimised with central composite design (H2O2/soil 0.081, Fe3+/soil 0.024, sodium pyrophosphate (SP)/soil 0.024, pH of SP solution 7.73). The effect of contaminant aging on PAH removals was also investigated. Remarkable oxidative PAH removals were observed for the short aging and extended aging period (up to 86.73 and 70.61 % for PHE and FLUT, respectively). The impacts of CHP on soil biological, chemical and physical properties were studied for both spiked and aged soils. Overall, the soil functionality analyses after the proposed operating condition demonstrated that the values for soil respiration, electrical conductivity, pH and iron precipitation fell within acceptable limits, indicating the compatibility of the CHP process with land restoration.  相似文献   
99.
100.
Journal of Polymers and the Environment - This study aims to evaluate the effects of poly(2-ethyl-oxazoline) (PEOx) on the thermal properties, wettability, and optical properties of poly(lactic...  相似文献   
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