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1.
Y. Thomas He Arthur G. Fitzmaurice Azra Bilgin Sunkyung Choi Peggy O’Day John Horst James Harrington H. James Reisinger David R. Burris Janet G. Hering 《Applied Geochemistry》2010
The behavior of As in the subsurface environment was examined along a transect of groundwater monitoring wells at a Superfund site, where enhanced reductive dechlorination (ERD) is being used for the remediation of groundwater contaminated with chlorinated solvents. The transect was installed parallel to the groundwater flow direction through the treatment area. The ERD technology involves the injection of organic C (OC) to stimulate in situ microbial dechlorination processes. A secondary effect of the ERD treatment at this site, however, is the mobilization of As, as well as Fe and Mn. The concentrations of these elements are low in groundwater collected upgradient of the ERD treatment area, indicating that, in the absence of the injected OC, the As that occurs naturally in the sediment is relatively immobile. Batch experiments conducted using sediments from the site inoculated with an Fe(III)- and As(V)-reducing bacterium and amended with lactate resulted in mobilization of As, Fe and Mn, suggesting that As mobilization in the field is due to microbial processes. 相似文献
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The purpose of the present study was to elucidate in vitro effects of Hg(2+), Zn(2+), Ni(2+) and Cd(2+) on cytochrome P4501A1 (CYP1A1) dependent EROD activities in leaping mullet liver microsomes. Fish captured from the most polluted part of Izmir Bay, had highly elevated EROD activities, and induced CYP1A1 protein levels as determined by Western blotting. Although all of the metal ions caused inhibition of the initial velocity of the reaction, Hg(2+) and Cd(2+) exhibited much higher inhibitory effect at lower concentrations and they were evidently more potent inhibitors than others. The inhibitor concentration giving 50% inhibition (IC(50) values) of Zn(2+), Ni(2+), Cd(2+) and Hg(2+) of initial EROD activity were 107, 16, 1.3 and 0.15 micromolar, respectively. Glutathione (GSH) at 0.5 mM final concentration, completely reversed Ni(2+) and Cd(2+) inhibition of EROD activity indicating the protective action of GSH. 相似文献
3.
Estimation of Rock Cuttability from Shore Hardness and Compressive Strength Properties 总被引：6，自引：1，他引：6
Summary Shore hardness has been used to estimate some mechanical and physical properties of rocks for many years. This study differs
from previous studies in a way that it is directly oriented to rock cuttability. Two Shore hardness values (SH
1 andSH
2) and a coefficient of deformation value (K) have been measured for 30 different rock samples. In the first stage of the study, optimum specific energy values for 16
different rock samples obtained from full-scale cutting tests were correlated with the Shore hardness values of the same rock
samples changingSH
1 values from 9 to 66 andSH
2 values from 25 to 83, with deformation coefficient values changing from 26 to 195. In the second stage, the performance of
a roadheader used in the Kü?üksu (Istanbul) tunnel was recorded in detail and the instantaneous cutting rate of the machine
was determined. Then, the relationship between Shore hardness values, deformation coefficient and the instantaneous cutting
rate of the machine was determined for different formations encountered. It is concluded that there is a relationship between
Shore hardness values, optimum specific energy and compressive strength, which may be used to estimate the rock cuttability
and the instantaneous cutting rates of roadheaders within certain limits of reliability. 相似文献
4.
Azra Bozcaarmutlu Canan Sapmaz Zuleyha Aygun Emel Arinç 《Marine environmental research》2009,67(4-5):167-176
Aim of this study was to determine the extent of pollution in the West Black Sea Coast of Turkey by measuring CYP1A associated EROD activity, phase II enzyme, glutathione S-transferase and antioxidant enzymes, catalase and glutathione reductase activities and immunochemical detection of CYP1A protein level in the liver of mullet. The fish samples were caught from six locations having a varying degree of pollution in the West Black Sea Region of Turkey in August 2005, 2006 and 2007. Mullets caught from Zonguldak Harbour, Ere?li Harbour and Gülüç Stream’s Mouth displayed 6–9-fold higher EROD, 2–4-fold higher glutathione S-transferase and 2–3-fold higher catalase activities than the reference site, Amasra. Total polyaromatic hydrocarbon levels in mullets caught from these locations were also significantly higher (2–4-fold) than Amasra. The results of this study indicate that Zonguldak Harbour, Ere?li Harbour and Gülüç Stream are highly polluted by polycyclic aromatic hydrocarbons and related contaminants. 相似文献
5.
In order to characterize the seasonal, bathymetric, and spatial distribution of the species, Palaemon adspersus, Palaemon elegans, and Crangon crangon, shrimps were sampled with a beam trawl in four stations at depths between 1 and 30 m from February 2002 to January 2004 on the Sinop Peninsula coasts of the southern Black Sea. One-way analysis of similarity (ANOSIM) results demonstrated that the caridean composition was significantly different (p < 0.001) between seasons and between sampling areas. No significant relationship of the caridean composition was evident between depth zones ranging from 1 to 30 m. These three carideans occurred together in 28.5% of the sampling occasions. Different seasonal migration pattern was evident for all the three species. Palaemon adspersus migrated inshore during relatively higher water temperatures, whereas C. crangon density decreased in the shallow waters during the same period, and P. elegans population was mostly observed at depth zones of 5–10 m and was only observed in the 30 m depth zone in winter. The abiotic factors that characterize the coexistence of these three carideans were primarily determined by the habitat types and bottom structures. 相似文献
6.
Numerical studies of anchored sheet pile wall behavior constructed in cut and fill conditions 总被引：1，自引：0，他引：1
The construction of sheet pile walls may involve either excavation of soils in front or backfilling of soils behind the wall. These construction procedures generate different loading conditions in the soil and therefore different wall behavior should also be expected. The conventional methods, which are based on limit equilibrium approach, commonly used in the design of anchored sheet pile walls do not consider the method of construction. However, continuum mechanics numerical methods, such as finite element method, make it possible to incorporate the construction method during the analyses and design of sheet pile walls. The effect of wall construction type for varying soil conditions and wall heights were investigated using finite element modeling and analysis. The influence of construction method on soil behavior, wall deformations, wall bending moments, and anchor forces were investigated. The study results indicate that walls constructed by backfill method yield significantly higher bending moments and wall deformations. This paper presents the results of the numerical parametric study performed and comparative analyses of the anchored sheet pile walls constructed by different construction methods. 相似文献
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8.
Janet G. Hering Peggy A. O'Day Robert G. Ford Y. Thomas He Azra Bilgin H. James Reisinger David R. Burris 《Ground Water Monitoring & Remediation》2009,29(3):84-92
The potential application of monitored natural attenuation (MNA) as a remedy for ground water contaminated with arsenic (As) is examined for a subset of contaminated sites, specifically those where naturally occurring As has been mobilized due to localized anthropogenic organic carbon (OC) releases. This includes sites subject to petroleum releases, exposure to landfill leachates, and OC additions for biostimulation of reductive dechlorination of chlorinated solvents. The key characteristic of these sites is that, under conditions prevailing before the anthropogenic OC introduction, the naturally occurring As in the subsurface was not mobile and did not adversely affect ground water quality. This suggests that, in the far-field (where background conditions are (re) established), As may be sequestered upon contact of the contaminated ground water with either or both the (uncontaminated) ambient ground water and the background aquifer minerals. The observed extents of elevated concentrations (or "footprints") of As and other chemical species, such as dissolved OC and iron (Fe), and related parameters, such as redox potential ( E h ) and dissolved oxygen, and their evolution over time can be used to assess the mobilization and sequestration of As and the potential feasibility of MNA as a remedial option. Ultimately, the capacity for As sequestration must be assessed in the context of the OC loading to the site, which may require "active" measures for source control. Monitoring is needed to confirm the continuing effectiveness of the MNA remedy or to indicate if contingency measures must be implemented. 相似文献
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