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In recent years, several studies focused on the detection of hydrocarbon pollution in the environment using hyperspectral remote sensing. Particularly the indirect detection of hydrocarbon pollution, using vegetation reflectance in the red edge region, has been studied extensively. Bioremediation is one of the methods that can be applied to clean up polluted sites. So far, there have been no studies on monitoring of bioremediation using (hyperspectral) remote sensing. This study evaluates the feasibility of hyperspectral remote sensing for monitoring the effect of bioremediation over time. Benzene leakage at connection points along a pipeline was monitored by comparing the red edge position (REP) in 2005 and 2008 using HyMap airborne hyperspectral images. REP values were normalized in order to enhance local variations caused by a change in benzene concentrations. 11 out of 17 locations were classified correctly as remediated, still polluted, or still clean, with a total accuracy of 65%. When only polluted locations that were remediated were taken into account, the (user's) accuracy was 71%. 相似文献
3.
Two biodegradation models are developed torepresent natural attenuation of fuel－hydrocarbon contaminants as observed in a comprehensive natural-gradient tracer test in a heterogeneous aquifer on the Columbus Air Force Basein Mississippi,USA．The first, a first-order mass loss model,describes the irreversible losses of BTEX and its individual components, i．e．,benzene（B）,toluene（T）,ethyl benzene（E）,and xylene（X）．The second, a reactive pathway model,describe ssequential degradation pathways for BTEX utilizing multiple electron acceptors,including oxygen,nitrate,iron and sulfate,and via methanogenesis．The heterogeneous aquifer is represented by multiple hydraulic conductivity（ K） zones delineated on the basis of numerous flowmeter K measurements．A direct propagation artificial neural network（DPN）is used as an inverse modeling tool to estimate the biodegradation rate constants associated with each of the K zones．In both the mass loss model and the reactive pathway model,the biodegradation rate constants show an increasing trend with the hydraulic conductivity．The finding of correlation between biodegradation kinetics and hydraulic conductivity distributions is of general interest and relevance to characterization and modeling of natural attenuation of hydrocarbons in other petroleum-product contaminated sites． 相似文献
4.
A laboratory experiment with two sequenced columns was performed as a preliminary study for the installation of a permeable
reactive barrier (PRB) at a site where a mixed ground water contamination exists. The first column contained granular zero
valent iron (ZVI), the second column was filled with granular activated carbon (GAC). Trichloromethane (TCM, 930 μg/l) and
chlorobenzene (MCB, 260 μg/l) were added to the ground water from the site as the main contaminants. Smaller amounts (<60 μg/l)
of benzene, 1,2-dichloroethane, 1,1,2-trichloroethane (1,1,2-TCA), 1,1-dichloroethene (1,1-DCE), trichloroethene (TCE), tetrachloroethene
(PCE), 1,2-dichloropropane (1,2-DCP), bromodichloromethane (BDCM), dibromochloromethane (DBCM), tribromomethane (TBM), vinyl
chloride and chromate were also added to the water to simulate the complex contamination pattern at the site of interest.
PCE, TCE, 1,1-DCE, DBCM, BDCM, TBM, MCB and chromate were remediated in contact with ZVI, while the remaining contaminants
showed incomplete degradation. A fraction of 8–16.5% TCM was converted to dichloromethane (DCM). Remaining contaminant concentrations
were efficiently sorbed by the GAC until breakthrough of DCM was observed after 1,230 exchanged pore volumes in the GAC. The
results show that the complex mixture of contaminants can be remediated by a sequenced PRB consisting of ZVI and GAC and that
DCM sorption capacity is the critical parameter for the dimensions of the GAC reactor. 相似文献
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Assessment of natural attenuation of aromatic hydrocarbons in groundwater near a former manufactured-gas plant, South Carolina, USA 总被引：1，自引：0，他引：1
J. E. Landmeyer F. H. Chapelle M. D. Petkewich P. M. Bradley 《Environmental Geology》1998,34(4):279-292
Shallow, anaerobic groundwater near a former manufactured-gas plant (MGP) in Charleston, South Carolina, USA, contains mono-
and polycyclic aromatic hydrocarbons (MAHs and PAHs, respectively). Between 1994 and 1997, a combination of field, laboratory,
and numerical-flow and transport-model investigations were made to assess natural attenuation processes affecting MAH and
PAH distributions. This assessment included determination of adsorption coefficients (K
ad
) and first-order biodegradation rate constants (K
bio
) using aquifer material from the MGP site and adjacent properties. Naphthalene adsorption (K
ad
=1.35×10–7 m3/mg) to aquifer sediments was higher than toluene adsorption (K
ad
=9.34×10–10 m3/mg), suggesting preferential toluene transport relative to naphthalene. However, toluene and benzene distributions measured
in January 1994 were smaller than the naphthalene distribution. This scenario can be explained, in part, by the differences
between biodegradation rates of the compounds. Aerobic first-order rate constants of 14C-toluene, 14C-benzene, and 14C-naphthalene degradation were similar (–0.84, –0.03, and 0.88 day–1, respectively), but anaerobic rate constants were higher for toluene and benzene (–0.002 and –0.00014 day–1, respectively) than for naphthalene (–0.000046 day–1). Both areal and cross-sectional numerical simulations were used to test the hypothesis suggested by these rate differences
that MAH compounds will be contained relative to PAHs. Predictive simulations indicated that the distributions of toluene
and benzene reach steady-state conditions before groundwater flow lines discharge to an adjacent surface-water body, but do
discharge low concentrations of naphthalene. Numerical predictions were "audited" by measuring concentrations of naphthalene,
toluene, and benzene at the site in early 1997. Measured naphthalene and toluene concentrations were substantially reduced
and the areal extent of contamination smaller than was both observed in January 1994 and predicted for 1997. Measured 1997
benzene concentrations and distribution were shown to be relatively unchanged from those measured in 1994, and similar to
predictions for 1997.
Received: 26 June 1997 · Accepted: 25 August 1997 相似文献
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Pseudomonas putida MHF 7109 has been isolated and identified from cow dung microbial consortium for biodegradation of selected petroleum hydrocarbon compounds – benzene, toluene, and o‐xylene (BTX). Each compound was applied separately at concentrations of 50, 100, 250, and 500 mg L?1 in minimal salt medium to evaluate degradation activity of the identified microbial strain. The results indicated that the strain used has high potential to degrade BTX at a concentration of 50 mg L?1 within a period of 48, 96, and 168 h, respectively; whereas the concentration of 100 mg L?1 of benzene and toluene was found to be completely degraded within 120 and 168 h, respectively. Sixty‐two percent of o‐xylene were degraded within 168 h at the 100 mg L?1 concentration level. The maximum degradation rates for BTX were 1.35, 1.04, and 0.51 mg L?1 h?1, respectively. At higher concentrations (250 and 500 mg L?1) BTX inhibited the activity of microorganisms. The mass spectrometry analysis identified the intermediates as catechol, 2‐hydroxymuconic semialdehyde, 3‐methylcatechol, cis‐2‐hydroxypenta‐2,4‐dienoate, 2‐methylbenzyl alcohol, and 1,2‐dihydroxy‐6‐methylcyclohexa‐3,5‐dienecarboxylate, for BTX, respectively. P. putida MHF 7109 has been found to have high potential for biodegradation of volatile petroleum hydrocarbons. 相似文献
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新疆地震局＾１４Ｃ实验室为提供准确可靠＾１４Ｃ年代 数据,在选择,制备、测量本底苯,制备、测量糖碳苯,分析产品的淬灭对＾１４Ｃ年代的影响等方面进行了有效的试验与探讨。 相似文献
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Jennifer M.K. O'KeefeErika R. Neace Edward W. LemleyJames C. Hower Kevin R. HenkeGregory Copley Rachel S. HatchAnne B. Satterwhite Donald R. Blake 《International Journal of Coal Geology》2011,87(2):150-156
Vent emissions of the Old Smokey coal fire, Floyd County, Kentucky, were studied in May and July, 2010. Vent emissions were generally lower in July, perhaps due to a shift in the fire front, change in vent structure, or another unidentified factor. Volatile organics in the vent gasses contain dangerous levels of toxic, carcinogenic, and other hazardous compounds. Benzene ranges to nearly 400 parts per billion (volume) at one vent. Toluene exceeds 104 parts per billion (volume) at the same vent.Flux rates for CO2 and CO range to 85,000 mg/s/m2 and 89 mg/s/m2, respectively, for various vents for the two measuring times. Estimates of total CO2 emissions, possibly less than 1000 t/year, are within the range of other eastern Kentucky coal fires. 相似文献
9.
利用浸渍法制备负载型V2O5/Na2SiO3催化剂,并通过XRD、IR、TG-DSC手段对催化剂进行了结构和热分析表征。在以Na2SiO3为载体的基础上,以V2O5为催化剂,通过改变V2O5的负载量,考查了不同负载量的V2O5催化剂对苯氧化为苯酚的催化性能的影响。实验结果表明,当V2O5的负载量为1%时,V2O5的催化性能最好,这是由于V2O5高度分散于Na2SiO3载体上,增大了活性组分V2O5的表面积,从而增加了其活性中心个数及活性组分与反应物的接触面积,增加了其催化活性。 相似文献
10.
P. Bruno M. Caselli G. de Gennaro L. de Gennaro M. Tutino 《Journal of Atmospheric Chemistry》2006,54(2):177-187
Atmospheric concentrations of benzene and toluene were assessed during three different seasons in the city of Taranto, using Radiello® diffusive samplers, in order to detect the most critical areas and to point out the sources contributing to pollution (vehicular traffic or industrial activities). High spatial resolution maps were built using a grid of 30 meshes drawn on the urban area of the city. For each mesh a monitoring site as representative as possible was chosen. Besides, in order to describe the highest levels of pollutants to which people is exposed, other 10 sampling sites were detected near high vehicular traffic crossroads or in particular critical zones of the city. The measurements of the concentration of these pollutants were carried out with Radiello® diffusive samplers for thermal desorption. The analysis of the results and the comparison between the map of vehicular traffic flows and the map of the concentrations of benzene suggested that in urban area the main benzene source is the traffic and the most significant pollution phenomena happens in zones characterized by narrow roads. Moreover it was possible to observe that high concentrations of benzene found in the NE zone of Taranto could be assigned to the industrial activities. This hypothesis was confirmed considering the diagnostic ratio between the toluene and benzene concentrations. 相似文献