Abbau aromatischer Kohlenwasserstoffe und Metabolitenbildung im Grundwasserleiter eines ehemaligen Gaswerkstandorts

Abstract

GrundwasserGrundwasser Grundwasser Grundwasser Grundwasser -Zeitschrift der Fachsektion Hydrogeologie 2/98 Kurzfassung Auf dem kontaminierten Gelände eines ehemaligen Gaswerkstandorts in Düsseldorf wurden von Oktober 1995 bis November 1996 hydrochemische Untersuchungen durchgeführt. Die im Zuge der seit Dezember 1995 laufenden Grundwasser-und Boden-Sanierung auftretenden Veränderungen der mikrobiologischen Abbauprozesse im Grundwasserleiter wurden analysiert. Als organische Schadstoffe waren vor allem BTEX (Benzol, Toluol, Ethylbenzol, Xylole) und niedermolekulare PAK (polyzyklische aromatische Kohlenwasserstoffe) im Grundwasser vertreten. Zu Beginn der Sanierung vollzog sich der natürliche Abbau der Schadstoffe unter Sulfatreduktion als vorherrschendem elektronenakzeptierenden Prozeß. Aufgrund von Sauerstoffeintrag in den Grundwasserleiter im Zuge der Bodenauskofferung wurde dieser Schadstoffabbau gestört. Die Folge waren deutlich ansteigende Konzentrationen an aromatischen Kohlenwasserstoffen und Sulfat. Die beim Abbau der aromatischen Kohlenwasserstoffe auftretenden aromatischen Säuren zeigten spezifische Veränderungen der Abbauprozesse an. AbstractHydrochemical investigations were performed at a contaminated site in the area of a former gasplant at Düsseldorf, Germany, between October, 1995 and November, 1996. The changes of the biodegradation processes in the aquifer during the remediation of groundwater and soil were monitored. The organic contaminants present in the groundwater were mainly BTEX (benzene, toluene, ethylbenzene, xylenes) and low molecular weight PAH (polycyclic aromatic hydrocarbons). At the beginning of the remediation activities, natural degradation of the contaminants occurred with sulfate reduction as the prevailing terminal electron accepting process. Due to oxygen input into the aquifer during soil removal the biodegradation process was disturbed and the concentrations of aromatic hydrocarbons and sulfate rose significantly. The aromatic acids occuring as metabolites of the aromatic hydrocarbons reacted specifically to the changes in the degradation processes.

Degradation of 2-Methylnaphthalene by a Sulfate-Reducing Enrichment Culture of Mesophilic Freshwater Bacteria

“…Detection of naphthyl-2-methyl-succinate and 2-naphthoate in the enrichment culture indicated that the initial reactions of 2-MN metabolism probably include addition of fumarate to the methyl group of the compound and further degradation to 2-naphthoate as it was suggested earlier (15,18). Such a pathway was elucidated in detail for the degradation of toluene by nitrate-reducing bacteria, and also occurred in sulfatereducing and anoxygenic phototrophic bacteria (19,(26)(27)(28)(29)(30).…”

“…During bioremediation of groundwater in the area of a former gas plant at Düsseldorf, Germany, the production of naphthylmethylsuccinate was detected (18). That suggested that MNs were metabolized through fumarate addition to the methyl group (18).…”

“…During bioremediation of groundwater in the area of a former gas plant at Düsseldorf, Germany, the production of naphthylmethylsuccinate was detected (18). That suggested that MNs were metabolized through fumarate addition to the methyl group (18). So far, enrichment cultures of freshwater and marine sulfate-reducing bacteria were obtained that mineralized 2-MN but not 1-MN (16,17,20).…”