Fate of gasoline oxygenates in conventional and multilevel wells of a contaminated groundwater table in düsseldorf, Germany

Abstract

In a gasoline-contaminated site in Düsseldorf, Germany a two-year monitoring program was carried out to determine the presence, behavior, and fate of 12 gasoline additives in a total of 96 samples from 14 groundwater wells. The origin of contamination was suspected to be a gasoline spill at a gas station. Target compounds were methyl-tert-butyl ether (MTBE), its main degradation products, tert-butyl alcohol (TBA) and tert-butyl formate (TBF); other gasoline additives, oxygenate dialkyl ethers: Ethyl-tert-butyl ether (ETBE), tert-amyl methyl ether (TAME) and diisopropyl ether (DIPE); aromatics: Benzene, toluene, ethylbenzene and xylenes (BTEX), and other compounds causing odor problems: Dicyclopentadiene and trichloroethylene. Purge and trap coupled with gas chromatography-mass spectrometry permitted detection of ng/L concentrations. Ninety of the 96 samples analyzed contained MTBE at levels varying between 0.01 to 645 microg/L. Five contaminated hot spots were identified with levels up to U.S. Environmental Protection Agency (U.S. EPA) drinking water advisory values (20-40 microg/L) and one of them doubling Danish suggested toxicity level of 350 microg/L at a depth of 11 m. No significant natural attenuation was found in MTBE degradation, although samples with high levels of MTBE contained 0.1 to 440 microg/L of TBA. These levels were attributed to its presence in the contamination source more than MTBE degradation. tert-Butyl alcohol was found to be recalcitrant in groundwater. In all cases, BTEX were at low concentrations or not detected, showing less persistence than MTBE. The monitoring of the contamination plume showed that the distribution of the MTBE and TBA in the aquifer formed a similar vertical concentration profile that was influenced by the groundwater flow direction.

Distribution of ETBE-degrading microorganisms and functional capability in groundwater, and implications for characterising aquifer ETBE biodegradation potential

“…Concentrations of ETBE, TBA and dissolved oxygen are typically monitored in groundwater at ETBE-release sites to demonstrate aerobic biodegradation of ETBE (Rosell et al 2005 ; Fayolle-Guichard et al 2012 ; Stupp et al 2012 ; Bombach et al 2015 ; van der Waals et al 2018 ; Nicholls et al 2020 ; Thornton et al 2020 ). The detection of the ethB gene in aquifer samples can provide additional microbiological-based evidence to support the hydrochemical assessment, complementing other molecular tools which may be deployed to evaluate GEO biodegradation (e.g.…”

“…Concentrations of ETBE, TBA and dissolved oxygen are typically monitored in groundwater at ETBE-release sites to demonstrate aerobic biodegradation of ETBE (Rosell et al 2005; Fig. 4 Plot of ethB to 16S rRNA gene copy number ratios for Site F, well F2, and Site T, wells T1 and T2, according to different purged borehole volumes (1, 3 or 6).…”

Evaluation of evidence for infection as a mode of action for induction of rat lymphoma

“…Methanol, formaldehyde, aspartame, and MTBE have common metabolites. DIPE, TAME, methanol and MTBE have chemical and physical properties in common such that they are all described as gasoline-oxygenate additives [Rosell et al, 2005;Zein et al, 2006]. Therefore, there is coherence and apparent chemical specificity for induction of this specific tumor type that would not be expected from a MOA of generalized infection in the rat colony.…”

Characterization and Testing of Periodic Mesoporous Organosilicas as Potential Selective Benzene Adsorbents

“…Of particular interest is the gas-phase detection of benzene at trace levels in mixtures containing similarly structured aromatic molecules such as toluene and xylene as well as other hydrocarbons. The gas-phase analysis of benzene/toluene/xylene (BTX) mixtures at trace levels (≤100 ppb) typically employs GC or GC-MS methods either via direct headspace analysis , or in combination with a cryogenic or solid-phase microextraction ,, preconcentrator. While this technology excels for laboratory analysis, major technical hurdles must be overcome (e.g., μ-GC) to adapt these methods to real-time personal exposure monitoring.…”