A review on the aging phenomena of organic components and their mass transfer through the NAPL interfacial phase

Liu, Lihua; Haderlein, Stefan B.

doi:10.1007/s11631-013-0630-6

Cited by 3 publications

(1 citation statement)

References 71 publications

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“…Commonly, only a limited range of compounds is considered in modeling approaches, most prominently a selection of 16 EPA-listed PAH, which are among the most abundant constituents (Brown et al, 2006;Vasilieva et al, 2012a,b) at tar oil impacted soils, aquifers and sediments. Moreover, coal tars undergo a variety of aging processes in the decades following their release into the subsurface that further complicate the prediction of their behavior (Liu and Haderlein, 2013). The effect of the genesis of phase-internal gradients within a multicomponent DNAPL due to leaching of well soluble compounds over time, and the development of high-viscosity skins (Alshafie and Ghoshal, 2004) or emulsions (Nelson et al, 1996) at the phase interface on coal tar dissolution have been noted and documented in laboratory studies (Nelson et al, 1996;Alshafie and Ghoshal, 2004) but to our knowledge, not under field conditions.…”

Section: Introductionmentioning

confidence: 99%

Composition and Dissolution of a Migratory, Weathered Coal Tar Creosote DNAPL

Scherr

Vasilieva

Lantschbauer

et al. 2016

Front. Environ. Sci.

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Opaque, viscous tars derived from the carbonization of fossile carbon feedstocks, such coal tars and creosote, are long-term sources of groundwater contamination, predominantly with poly-and heterocyclic aromatic hydrocarbons (PAH). The dissolution, aging and migratory behavior of dense, non-aqueous phase liquid (DNAPL) coal tar blobs and pools forming at the aquitard is not sufficiently understood to estimate the risk and adequately design groundwater treatment measures at a contaminated site. In this study, we investigate the composition and dissolution of a migrated, aged creosote DNAPL, and corresponding experimental and groundwater profiles using comprehensive two-dimensional gas chromatography (GCxGC-MS). GC-FID unresolved compounds were attributed to methylated homocyclic species using GCxGC-MS in the Methylanthracene weight range. Equilibrium concentrations were estimated using Raoult's law, assuming non-ideal behavior. Low molecular weight compounds were found to be prevalent even after decades of weathering, with Naphthalene (8% by mass) representing the most abundant identified compound, contrary to the expected preferential depletion of hydrophilic compounds. Morevoer, dimethylnaphthalenes were relatively more abundant in the aqueous boundary layer than in the DNAPL. DNAPL migration over 400 m with the groundwater flow effected lower viscosity and specific gravity of the migrated phase body in a superposition of weathering, transport, and aquifer chromatography effects. Based on a decomposition of analyzed and estimated constituents using the group contribution approach, reference DNAPL values for activity coefficients γ i were used to model aqueous solubilities for selected compounds. Anthracene was close to its theoretical precipitation limit in the bulk DNAPL. While laboratory and modeled DNAPL dissolution behavior agree well, field data imply the presence of specific interfacial in situ processes significantly impacting dissolution processes. Based on aqueous GCxGC-MS profiles over the DNAPL, a hypothetical interfacial in situ film was calculated to be composed primarily of Phenanthrene, with minor contribution by Naphthalene, possibly forming a viscous barrier for the dissolution Scherr et al.Environmental Coal Tar DNAPL Weathering of lower molecular weight PAH. The main advances and gaps in electron donor DNAPL understanding are discussed regarding our conception of weathered, migrating hydrophobic DNAPL bodies in the aquifer of historic contaminated sites for the adequate treatment of contaminated water.

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Section: Introductionmentioning

confidence: 99%

Composition and Dissolution of a Migratory, Weathered Coal Tar Creosote DNAPL

Scherr

Vasilieva

Lantschbauer

et al. 2016

Front. Environ. Sci.

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Migration and remediation of organic liquid pollutants in porous soils and sedimentary rocks: a review

et al. 2022

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Assessing bioavailability of complex chemical mixtures in contaminated soils: Progress made and research needs

Cipullo

Prpich

Campo

et al. 2018

Science of The Total Environment

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Understanding the distribution, behaviour and interactions of complex chemical mixtures is key for providing the evidence necessary to make informed decisions and implement robust remediation strategies. Much of the current risk assessment frameworks applied to manage land contamination are based on total contaminant concentrations and the exposure assessments embedded within them do not explicitly address the partitioning and bioavailability of chemical mixtures. These oversights may contribute to an overestimation of both the eco-toxicological effects of the fractions and the mobility of contaminants. In turn, this may limit the efficacy of risk frameworks to inform targeted and proportionate remediation strategies. In this review we analyse the science surrounding bioavailability, its regulatory inclusion and the challenges of incorporating bioavailability in decision making process. While a number of physical and chemical techniques have proven to be valuable tools for estimating bioavailability of organic and inorganic contaminants in soils, doubts have been cast on its implementation into risk management soil frameworks mainly due to a general disagreement on the interchangeable use of bioavailability and bioaccessibility, and the associated methods which are still not standardised. This review focuses on the role of biotic and abiotic factors affecting bioavailability along with soil physicochemical properties and contaminant composition. We also included advantages and disadvantages of different extraction techniques and their implications for bioavailability quantitative estimation. In order to move forward the integration of bioavailability into site-specific risk assessments we should (1) account for soil and contaminant physicochemical characteristics and their effect on bioavailability; (2) evaluate receptor's potential exposure and uptake based on mild-extraction; (3) adopt a combined approach where chemical-techniques are used along with biological methods; (4) consider a simplified and cost-effective methodology to apply at regulatory and industry setting; (5) use single-contaminant exposure assessments to inform and predict complex chemical mixture behaviour and bioavailability.

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A review on the aging phenomena of organic components and their mass transfer through the NAPL interfacial phase

Cited by 3 publications

References 71 publications

Composition and Dissolution of a Migratory, Weathered Coal Tar Creosote DNAPL

Composition and Dissolution of a Migratory, Weathered Coal Tar Creosote DNAPL

Migration and remediation of organic liquid pollutants in porous soils and sedimentary rocks: a review

Assessing bioavailability of complex chemical mixtures in contaminated soils: Progress made and research needs

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