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141.
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Mark E. Thompson Herbert H. Stoevener 《Journal of the American Water Resources Association》1983,19(6):889-896
ABSTRACT: An implicit price model relating residential lot value to price determining characteristics of land is developed to measure the benefits of a structural flood control project. Special attention is given to the selection of relevant price determining characteristics of residential lots. An implicit price equation is estimated for both the with and without project conditions. Flood damages are quantified through the use of a dummy variable indicating a flood plain location. The analysis shows that annual flood damages were reduced by $15,275. 相似文献
143.
Bossew P Gastberger M Gohla H Hofer P Hubmer A 《Journal of environmental radioactivity》2004,73(1):87-99
Five soil profiles from a site about 8 km SE of the Chernobyl NPP were investigated for the vertical distribution of radionuclides. The average (137)Cs-inventory at the site is about 2.6 MBq/m(2) (reference date 1 May 1986). Apart from (137)Cs, the following radionuclides have been identified (their activity ratios to (137)Cs in brackets): (134)Cs (0.537), (125)Sb (0.068), (60)Co (0.0022), (154)Eu (0.016), (155)Eu (0.020), (94g)Nb (9.5E-5), (239/240)Pu (0.0088), (238)Pu (0.040), (90)Sr (0.30) and (241)Am (0.011). Apparent vertical migration velocities are between 0.14 and 0.26 cm/a, apparent dispersion coefficients range from 0.02 to 0.13 cm(2)/a. The rankings of the velocities v for different radionuclides are (Sr, Cs, Sb, Co, Pu)< Am < Eu and Sr < (Cs, Nb), for D, the following rankings have been found: (Nb, Sr, Cs) < Am < Eu, Cs相似文献
144.
Rauret G López-Sánchez JF Sahuquillo A Barahona E Lachica M Ure AM Davidson CM Gomez A Lück D Bacon J Yli-Halla M Muntau H Quevauviller P 《Journal of environmental monitoring : JEM》2000,2(3):228-233
This paper provides additional data on a sewage sludge amended soil certified reference material, CRM 483, which was certified in 1997 for its EDTA and acetic acid extractable contents of some trace metals, following standardised extraction procedures. The additional work aimed to test the long-term stability of the material and the applicability of an improved version of the BCR three-step sequential extraction procedure on the sewage sludge amended soil (CRM 483). The paper demonstrates the CRM 483 long-term stability for EDTA and acetic acid extractable contents of Cd, Cr, Cu, Ni, Pb and Zn and gives the results (obtained in the framework of an interlaboratory study) for the extractable contents of the same elements in the CRM 483, following the BCR three-step sequential extraction scheme. The aqua regia extractable contents following the ISO 11466 Standard are also given. The data are given as indicative (not certified) values. 相似文献
145.
Qingmei Yan Xuxiang Zhang Tong Zhang Herbert H. P. Fang 《Frontiers of Environmental Science & Engineering in China》2011,5(1):40-47
Activated sludge was monthly sampled from a saline sewage treatment plant of Hong Kong (China) during June 2007 to May 2008
to analyze the microbial community shift along with environmental variations using denaturing gradient gel electrophoresis
of polymerase chain reaction amplified 16S rDNA fragments. Environmental changes resulted into a seasonal microbial community
shift characterized by alterations in species number and abundance in the sewage treatment plant. Correspondence analysis
and cluster analysis on community structure profile showed that the 12 monthly samples fell into four groups, which is in
accordance with season changing in Hong Kong. Canonical correspondence analysis revealed that PO43t- -P and NH4+ -N posed more significant effects on community structure than total phosphorus and total nitrogen, respectively. Compared
with sludge retention time, influent total phosphorus had an inverse effect on the community structure shift, and chemical
oxygen demand and NH4+ -N showed a similar effects. Results of this study may contribute to the development of new knowledge involving the microbial
community shift in sewage treatment plants. 相似文献
146.
In general, indoor radon concentration is subject to seasonal variability. The reasons are to be found (1) in meteorological influence on the transport properties of soil, e.g. through temperature, frozen soil layers and soil water saturation; and (2) in living habits, e.g. the tendency to open windows in summer and keep them closed in winter, which in general leads to higher accumulation of geogenic Rn in closed rooms in winter. If one wants to standardize indoor Rn measurements originally performed at different times of the year, e.g. in order to make them comparable, some correction transform as a function of measurement time which accounts for these effects must be estimated. In this paper, the seasonality of indoor Rn concentration measured in Austria is investigated as a function of other factors that influence indoor Rn. Indoor radon concentration is clearly shown to have seasonal variability, with higher Rn levels in winter. However, it is complicated to quantify the effect because, as a consequence of the history of an Rn survey, the measurement season maybe correlated to geological regions, which may introduce a bias in the estimate of the seasonality amplitude. 相似文献
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