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91.
Biochemical methane potential (BMP) assays, typically used to assess anaerobic biodegradability of liquid wastes with added nutrients and bacteria, were adapted to compare hydrolysis of lignocellulosic material under sulfidogenic and methanogenic environments. A method based on selective inhibition of microorganism activity, by 3% toluene, was used to measure the hydrolysis rate of lignocellulosic material and the accumulation of sugar. The neutral sugars, galactose, glucose, and xylose, which were released from lignocellulosic material such as office paper and newspaper in the presence 3% toluene, clearly accumulated over time under sulfidogenic conditions. The accumulation rates of sugars, glucose, and xylose, were higher in the sulfidogenic condition than in the methanogenic condition, indicating a faster degradation of lignocellulosic materials under the sulfidogenic condition. 相似文献
92.
Stormwater runoff from the University of California, Davis/U.S. Department of Energy Laboratory for Energy‐Related Health Research (UCD/US DOE LEHR) Superfund site located on the University of California campus in Davis, California, has been found to contain over 500 ng/L of total recoverable mercury, which is about ten times the California Toxics Rule criterion. This stormwater runoff is discharged to Putah Creek, which is Clean Water Act Section 303(d) listed as impaired for excessive mercury bioaccumulation in edible fish. A discussion is presented on the potential impact of the mercury in stormwater runoff from LEHR leading to excessive bioaccumulation of mercury in Putah Creek fish. The mercury in the stormwater runoff is derived from former flooding of the soils near the creek, which contains mercury derived from abandoned upstream mercury mines located in the Coast Range Vaca Hills to the west of LEHR. The implications of this situation for implementing a Total Maximum Daily Load (TMDL) to control mercury in stormwater runoff to Putah Creek are presented. © 2009 Wiley Periodicals, Inc. 相似文献
93.
Hyoung-June Im Young-Jun Kwon Soo-Geun Kim Yong-Kyu Kim Young-Su Ju Hwa-Pyung Lee 《Safety Science》2009,47(8):1159-1162
This study is aimed at exploring the characteristics of fatal occupational injuries in Korea’s construction industry and comparing the causes in various occupations within that industry. There were 10,276 fatal occupational injury victims in Korea over 8 years (1997–2004). The mortality risk due to injuries in construction and non-construction industries was calculated, and their causes were compared. The number of victims of fatal occupational injuries in the construction industry was 4333 (42.2% of the total fatal occupational injuries), and the 1 year mortality risk was higher (23.7/100,000 persons) than in non-construction industries (10.4). Falling was the most frequent (52.7%) cause of fatal injuries. In addition, deaths due to structural collapse and electric shock were significantly higher than in other industries. When the distribution of the causal factors in various occupations within the construction industry was investigated, some factors appeared more frequently in certain occupations than in others. As the construction industry encompasses a large proportion of occupational injuries, a reduction in this field alone will substantially contribute to an overall reduction of occupational injuries in Korea. Further research for effective prevention is needed. 相似文献
94.
95.
D.S. Lee R.D. Kingdon M.E. Jenkin A. Webster 《Environmental Modeling and Assessment》2000,5(2):105-118
In order to understand relationships between sources and receptors of atmospheric deposition, computer models must be used.
This paper describes a Lagrangian acid deposition model that represents emissions of trace species across Northern Europe.
The chemistry of sulphur dioxide, dimethyl sulphide and hydrogen sulphide is represented and the model tested against estimates
of UK wet and dry deposition. Mean UK wet and dry deposition for the period 1992–1994 was 206 and 145 ktonne S yr-1, respectively. The model predicted wet and dry deposition of 222 and 166 ktonne S yr-1, in good agreement with measurements. The model has been used to examine the sources of deposited S to the UK. For a base
year of 1992, 86% of the UK's SO2 emissions are exported. The S deposition attributable from mainland European sources was 36% of the UK total S deposition,
in good agreement with other UK models but this differs substantially from the calculations of the EMEP model. Natural sources
of S deposition from planktonic emissions of dimethyl sulphide, biological emissions of hydrogen sulphide and non-eruptive
volcanic emissions of sulphur dioxide contributed approximately 1% of the modelled UK S deposition, of which 95% originated
from dimethyl sulphide. The explicit chemical scheme for dimethyl sulphide incorporated into the model showed that 24% of
the resultant deposited S was methane sulphonic acid. Boundary conditions of the model were tested and it was found that initialisation
of sulphur dioxide and sulphate concentrations to representative ambient conditions had a very small effect. The modelled
contribution of UK and European sources to UK S deposition was approximately 40 and 60%, respectively, showing the dramatic
change arising from projected UK SO2 emissions in 2010.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
96.
Tsung-Hung Hsu Jen-Yang Lin Tsu-Chuan Lee Harry X. Zhang Shaw L. Yu 《Environmental monitoring and assessment》2010,163(1-4):81-94
It is vitally important to define the critical condition for a receiving water body in the total maximum daily load (TMDL) development process. One of the major disadvantages of using a continuous simulation approach is that there is no guarantee that the most critical condition will be covered within the subjectively selected representative hydrologic period, which is usually several years depending on the availability of data. Another limitation of the continuous simulation approach, compared to a design storm approach, is the lack of an estimate of the risk involved. Because of the above limitations, a storm event-based critical flow-storm (CFS) approach was previously developed to explicitly address the critical condition as a combination of a prescribed stream flow and a storm event of certain magnitude, both having a certain frequency of occurrence and when combined, would create a critical condition. The CFS approach was tested successfully in a TMDL study for Muddy Creek in Virginia. The present paper reports results of a comparative study on the applicability of the CFS approach in Taiwan. The Dy-yu creek watershed in northern Taiwan differs significantly from Muddy Creek in terms of climate, hydrology, terrain, and other characteristics. Results show that the critical condition for different watersheds might be also different, and that the CFS approach could clearly define that critical condition and should be considered as an alternative method for TMDL development to a continuous simulation approach. 相似文献
97.
The technical viability of using inert construction and demolition (C&D) materials for the construction of seawall and breakwater foundations has been established by laboratory testing of the materials, numerical analysis of foundation stability, and a pilot field-scale engineering performance evaluation. However, quality control measures are still required so that only suitable materials are used for seawall and breakwater foundation construction. The development of different quality control measures for different site conditions is presented in this paper. The rationale, practicality, and implementation of these quality control measures are also discussed. 相似文献
98.
To further understand the effects of wet scrubbers on PCDD/DF levels, it was measured the concentrations of PCDD/DF, dust, and other gaseous pollutants at both the inlets and the outlets of seven wet scrubbers. As a result, the concentrations of PCDD/DF at the inlets and outlets of the wet scrubbers ranged from 0.2 to 37.4, and 0.8 to 6.0 ng TEQ N m-3, respectively. With the exceptions of wet scrubbers F and G, the PCDD/DF levels decreased by and large in most wet scrubbers. It was thought that their relatively high removal efficiencies were more increased with heavier loads of dust and particle-bound PCDD/DF. On the other hand, it was also surveyed the increase of gaseous PCDD/DF in wet scrubber, where the total level of PCDD/DF was decreased. However, it was not sure whether it had been resulted from the thermal adsorption/desorption phenomenon between packing materials and emission gases or not. At the very least, however, although there still remains an unexplained aspect for the increase of gaseous PCDD/DF, it is clear that wet scrubbers can be sufficiently applied to remove PCDD/DF to a certain extent, if only removal efficiencies for the particle loads are high, and if a significant part of the PCDD/DF at the inlets is particle associated. 相似文献
99.
Composition and distribution of polycyclic aromatic hydrocarbons in the surface sediments from the Susquehanna River 总被引:6,自引:0,他引:6
Polycyclic aromatic hydrocarbon (PAH) concentrations in 34 surface sediments along the Susquehanna River were investigated in 2000. The total concentrations of PAHs in the surface sediments of Lake Clarke, Lake Aldred, the upper Conowingo Reservoir, and the lower Conowingo Reservoir were 3.3+/-1.5 microg g-1 (n=9), 1.6+/-1.3 microg g-1 (n=4), 9.8+/-5.5 microg g-1 (n=7), and 4.0+/-1.2 microg g-1 (n=14), respectively. These represent the first comprehensive measurement of PAHs in Susquehanna River surface sediments. Overall, total PAH concentrations were relatively lower in Lake Aldred, which is more shallow and sloped, and significantly higher in the upper Conowingo Reservoir. The sediment PAH levels were related to river flow rates, which are indirectly correlated with the particle size of the surface sediments. Total PAH levels in all the studied sites were below the effects range median (ERM) of 44.8 microg g-1 with 38% (13 of the 34 sampling sites) exceeding the effects range low (ERL) of 4.02 microg g-1. Principal component analysis indicated that variations in the PAH compound patterns of each reservoir decreased from upstream to downstream, indicating that the surface sediments were mixed along the Susquehanna River. The PAH patterns in the lower Conowingo Reservoir sediments were a combination of those upstream sources. Source analysis using isomer ratios as indicators suggested that PAHs in the Susquehanna River surface sediment are derived from the combustion of fossil fuels such as coal and gasoline with coal as the major source of contaminants. 相似文献
100.
Formation of leadhillite and calcium lead silicate hydrate (C-Pb-S-H) in the solidification/stabilization of lead contaminants 总被引:1,自引:0,他引:1
Lee D 《Chemosphere》2007,66(9):1727-1733
In this study, we have investigated the structure of Pb-doped solidified waste forms (SWF) for assessment of lead fixation. A large quantity of lead precipitates produced during the S/S, based upon the results of cement-water solution analysis, X-ray diffraction and electron probe microanalysis/electron dispersive spectroscopy investigations, have been shown to be principally leadhillite (lead carbonate sulfate hydroxide, Pb(4)SO(4)(CO(3))(2)(OH)(2)), lead carbonate hydroxide hydrate (3PbCO(3).2Pb(OH)(2).H(2)O) and two other unidentified lead salts. In the long curing, the lead species dissolved from the lead precipitates are fixed into the cement matrix, forming a gelling calcium lead silicate hydrate during cement-based solidification. On leaching the lead precipitates such as leadhillite were markedly dissolved/released and some dissolved lead species were adsorbed to silicate-rich surface of leached SWF with the subsequent formation of mainly amorphous gel of calcium lead silicate hydrate. 相似文献