Natural attenuation at tar oil contaminated sites - results from the German funding priority KORA

2006 ◽  
Vol 14 (2) ◽  
pp. 288-292
Author(s):  
N. Hüsers ◽  
P. Börke ◽  
P. Werner
Keyword(s):  
Natural Attenuation ◽  
Contaminated Sites ◽  
Tar Oil

Numerical analysis of soil microstructure reveals conditions for natural attenuation in aged tar oil contaminated soil

2021 ◽  
Author(s):  
Pavel Ivanov ◽  
Karin Eusterhues ◽  
Kai Uwe Totsche
Keyword(s):  
Soil Solution ◽  
Contaminated Soil ◽  
Natural Attenuation ◽  
Pore Space ◽  
Total Porosity ◽  
Control Soil ◽  
Soil Microstructure ◽  
Cell Counts ◽  
Good Protection ◽  
Tar Oil

<p>Understanding of ongoing biogeochemical processes (natural attenuation) within contaminated soils is crucial for the development of plausible remediation strategies. We studied a tar oil contaminated soil with weak grass vegetation at a former manufactured gas plant site in Germany. Despite of the apparent toxicity (the soil contained up to 120 g kg<sup>-1</sup> petroleum hydrocarbons, 26 g kg<sup>-1</sup> toxic metals, and 100 mg kg<sup>-1</sup> polycyclic aromatic hydrocarbons), the contaminated layers have 3-5 times as much cell counts as an uncontaminated control soil nearby. To test, if the geometry of the pore space provides favourable living space for microorganisms, we applied scanning electron microscopy to the thin sections and calculated on sets of 15 images per layer three specific Minkowski functionals, connected to soil total porosity, interface, and hydraulic parameters.</p><p>Our investigation showed that the uncontaminated control soil has a relatively low porosity of 15-20 %, of which 50-70 % is comprised of small (< 15 µm) pores. These pores are poorly connected and show high distances between them (mean distance to the next pore 10 µm). The dominating habitats in the control soil are therefore created by small pores. They provide good protection from predators and desiccation, but input of dissolved organic C and removal of metabolic products are diffusion limited. Coarser pores (>15 µm) provide less space (< 50 % of total porosity) and solid surface area (< 20 %), are prone to desiccation and offer less protection from predators. However, they serve as preferential flow paths for the soil solution (input of nutrients) and are well aerated, therefore we expect the microbial activity in them to appear in “hot moments”, i.e. after rain events.</p><p>All layers of the contaminated profile have higher porosities (20-70 %) than the control. Coarse pores comprise 83-90 % of total pore area and create 34-52 % of total interface. Pores are also more connected and tortuous than in the control soil, which implies a better aeration and circulation of soil solution. The loops of pore channels may retain soil solution and be therefore preferably populated with microorganisms. The small (< 15 µm) pores comprise less than 17 % of total porosity but represent a substantial proportion of the interface (48-66 % vs 82-91 % in control). In the uppermost layer of the contaminated profile, such pores occur in plant residues, are close to the largest pores (mean distance to the next pore 4 µm) and therefore, along with good protection, are supplied with air, water, and non-tar C. In the middle of the profile, the small pores, presumably constantly filled with water, are located within dense tar pieces remote from the neighbouring pores (mean distance to the next pore 22 µm), and therefore, with hindered aeration and no supply of non-tar C, may create anaerobic domains of tar attenuation.</p><p>Our results show that the contaminated soil offers more favourable conditions for microorganisms than the control soil, probably because the hydrocarbons provide suitable energy and nutrition sources and a beneficial pore space geometry.</p>

Assessment of microbial natural attenuation in groundwater polluted with gasworks residues

2004 ◽  
Vol 50 (5) ◽  
pp. 347-353 ◽  
Author(s):  
S. Schulze ◽  
A. Tiehm
Keyword(s):  
Natural Attenuation ◽  
Disposal Site ◽  
Multiple Line ◽  
Reducing Conditions ◽  
Groundwater Hydrochemistry ◽  
Tar Oil ◽  
Microcosm Studies ◽  
The Impact ◽  
Redox Zones

Intrinsic biodegradation, representing the key process in Natural Attenuation, was examined at a tar-oil polluted disposal site. Methods to assess microbial natural attenuation of BTEX and PAH included analysis of groundwater hydrochemistry, pollutant profiles, composition of the microflora, and microcosm studies. In the polluted groundwater downgradient the disposal site, oxygen and nitrate were only available adjacent to the groundwater table and at the plume fringes. In the anaerobic core of the plume, a sequence of predominating redox zones (methanogenic, sulphate-reducing, Fe(III)-reducing) was observed. Changing pollutant profiles in the plume indicated active biodegradation processes, e.g. biodegradation of toluene and naphthalene in the anaerobic zones. High numbers of microorganisms capable of growing under anaerobic conditions and of aerobic pollutant degrading organisms confirmed the impact of biodegradation at this site. In microcosm studies, the autochthonous microflora utilised toluene, ethylbenzene, and naphthalene under sulfate- and Fe(III)-reducing conditions. Additionally, benzene and phenanthrene were degraded in the presence of Fe(III). Under aerobic conditions, all BTEX and PAH were rapidly degraded. The microcosm studies in particular were suitable to examine the role of specific electron acceptors, and represented an important component of the multiple line of evidence concept to assess natural attenuation.

Quinoline and Derivatives at a Tar Oil Contaminated Site:  Hydroxylated Products as Indicator for Natural Attenuation?

2007 ◽  
Vol 41 (15) ◽  
pp. 5314-5322 ◽  
Author(s):  
Anne-Kirsten Reineke ◽  
Thomas Göen ◽  
Alfred Preiss ◽  
Juliane Hollender
Keyword(s):  
Natural Attenuation ◽  
Contaminated Site ◽  
Tar Oil

Comparison of field-observed and model-predicted plume trends at fuel-contaminated sites: Implications for natural attenuation rates

2005 ◽  
Vol 7 (11) ◽  
pp. 1099 ◽  
Author(s):  
Seung-Woo Jeong ◽  
Donald H. Kampbell ◽  
Youn-Joo An ◽  
Bruce M. Henry
Keyword(s):  
Natural Attenuation ◽  
Contaminated Sites

Enumeration of aromatic oxygenase genes to evaluate monitored natural attenuation at gasoline-contaminated sites

2008 ◽  
Vol 42 (3) ◽  
pp. 723-731 ◽  
Author(s):  
Brett R. Baldwin ◽  
Cindy H. Nakatsu ◽  
Loring Nies
Keyword(s):  
Natural Attenuation ◽  
Contaminated Sites ◽  
Monitored Natural Attenuation

Robustness of an aerobic metabolically vinyl chloride degrading bacterial enrichment culture

2011 ◽  
Vol 64 (9) ◽  
pp. 1796-1803 ◽  
Author(s):  
He-Ping Zhao ◽  
Kathrin R. Schmidt ◽  
Svenja Lohner ◽  
Andreas Tiehm
Keyword(s):  
Vinyl Chloride ◽  
Natural Attenuation ◽  
Enrichment Culture ◽  
Contaminated Sites ◽  
Contaminated Groundwater ◽  
Chlorinated Ethene ◽  
Equimolar Concentration ◽  
Bacterial Enrichment ◽  
Ph Tolerance

Degradation of the lower chlorinated ethenes is crucial to the application of natural attenuation or in situ bioremediation on chlorinated ethene contaminated sites. Recently, within mixtures of several chloroethenes as they can occur in contaminated groundwater inhibiting effects on aerobic chloroethene degradation have been shown. The current study demonstrated that metabolic vinyl chloride (VC) degradation by an enrichment culture originating from groundwater was not affected by an equimolar concentration (50 μM) of cis-1,2-dichloroethene (cDCE). Only cDCE concentrations at a ratio of 2.4:1 (initial cDCE to VC concentration) caused minor inhibition of VC degradation. Furthermore, the degradation of VC was not affected by the presence of trans-1,2-dichloroethene (tDCE), 1,1-dichloroethene (1,1-DCE), trichloroethene (TCE), and tetrachloroethene (PCE) in equimolar concentrations (50 μM). Only cDCE and tDCE were cometabolically degraded in small amounts. The VC-degrading culture demonstrated a broad pH tolerance from 5 to 9 with an optimum between 6 and 7. Results also showed that the culture could degrade VC concentrations up to 1,800 μM (110 mg/L).

Using dynamic flux chambers to estimate the natural attenuation rates in the subsurface at petroleum contaminated sites

2018 ◽  
Vol 619-620 ◽  
pp. 470-479 ◽  
Author(s):  
Iason Verginelli ◽  
Roberto Pecoraro ◽  
Renato Baciocchi
Keyword(s):  
Natural Attenuation ◽  
Contaminated Sites ◽  
Flux Chambers
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