Microbial Degradation of Tar Oil Compounds under Different Redox Conditions

Abstract

The microbial transformation of typical tar oil compounds such as acridine, benzo(b)thiophene, dibenzofuran, indane, and indene under different redox conditions was investigated in microcosm studies. Under aerobic conditions the inherent contamination in polluted soil as well as the added N-, S-, O-heterocyclic and homocyclic compounds were transformed predominantly apart from thiophene. 1-Indanone was detected by RP-HPLC-DAD and GC-MS as an intermediate metabolite from indane and indene. Under nitrate and sulfate reducing conditions indane, benzo(b)thiophene, and dibenzofuran were transformed in assays with the polluted soil samples from well B 65 and B 66 within 426 days, whereas they were persistent in assays with the highly polluted soil B 67. All heterocyclic and homocyclic compounds added to the non-contaminated soil from well B 85 were not degraded under nitrate and sulfate reducing conditions, too. The results indicate that for the decision, wether natural attenuation can be implemented in the remediation of contaminated site, in addition to BTEX and PAHs especially the fate of further tar oil compounds in anoxic aquifers has to be considered. Mikrobieller Abbau von Teerölbegleitstoffen unter verschiedenen Redox-BedingungenDer mikrobielle Umsatz von typischen Teerölsubstanzen, wie Acridin, Benzo(b)thiophen, Dibenzofuran, Indan und Inden, wurde unter verschiedenen Redoxbedingungen in Mikrokosmen untersucht. Unter aeroben Bedingungen wurde sowohl in belasteten Bodenproben die inhärente Kontamination als auch in unbelasteten Bodenproben die zudotierten heterocyclischen und homocyclischen Verbindungen außer Thiophen überwiegend umgesetzt. 1-Indanon wurde als ein intermediärer Metabolit von Indan und Inden mittels RP-HPLC-DAD und GC-MS nachgewiesen. Unter denitrifizierenden und desulfurizierenden Bedingungen wurden Indan, Benzo(b)thiophen und Dibenzofuran in Ansätzen mit den belasteten Bodenproben von Brunnen B 65 und B 66 innerhalb von 426 Tagen umgesetzt, während sie in denen mit dem hoch belasteten Boden B 67 persistent blieben. Alle heterocyclischen und homocyclischen Stoffe, die den Versuchen mit unbelastetem Boden von Brunnen B 85 zugesetzt wurden, wurden ebenfalls nicht abgebaut. Die Ergebnisse zeigen, dass für die Entscheidung, ob Natural Attenuation an einem Standort implementiert werden kann, neben BTEX und PAK besonders der Verbleib weiterer Teerölverbindungen in anaeroben Aquifern zu prüfen ist.

Direct analysis of aromatic pollutants using a HPLC-FLD/DAD method for monitoring biodegradation processes

“…Industrial wastes and accidental spills resulting in soil and groundwater contamination is becoming a global concern due to the toxicity and recalcitrance of many aromatic compounds 1 . Common pollutants found in industrial or manufactured gas work sites are known as benzene, toluene, ethylbenzene, xylene (BTEX), polyaromatic hydrocarbons (PAHs) and various chlorinated aromatic hydrocarbons 2,3 . These compounds are specified as hazardous, mostly classified as carcinogenic, and posing risk to human health and to the environment 1,3 .…”

Promotive effect of pyridine on indole degradation by activated sludge under anoxic conditions

“…Therefore, during the biological treatment of the wastewater, N-heterocyclic compounds will also be exposed to nitrate reducing conditions. Most of these compounds are thought to be recalcitrant to biodegradation without oxygen [10][11][12]. Recently, however, this view has changed as anaerobic biodegradations of some recalcitrant compounds have been found under sulfate-reducing and nitrate-reducing conditions [13][14][15][16].…”

Biostimulation strategies : For in situ biodegradation of complex aromatic contaminant mixtures in groundwater

“…Despite being common tar oil contaminants, indene and indane received little attention. Most of the existing research has mainly focused on their metabolic conversions or biodegradation using pure cultures and under aerobic conditions (Allen et al, 1995;Buckland et al, 1999;Chartrain et al, 1998;Mundt et al, 2003;Wackett et al, 1988). Few studies were reported upon their anaerobic biodegradation (Kleemann & Meckenstock, 2011;Muhr et al, 2015).…”

“…Industrial wastes and accidental spills resulting in soil and groundwater contamination is becoming a global concern due to the toxicity and recalcitrance of many aromatic compounds (Birak & Miller, 2009). Common pollutants found in industrial or manufactured gasworks sites are known as benzene, toluene, ethylbenzene, xylene (BTEX), polyaromatic hydrocarbons (PAHs) and various chlorinated aromatic hydrocarbons (Jandera et al, 2001;Mundt et al, 2003). These compounds are specified as hazardous, mostly classified as carcinogenic, and posing risk to human health and to the environment (Birak & Miller, 2009;Jandera et al, 2001).…”

“…Tar oil is a complex mixture containing a large number of hydrophobic compounds (Murphy et al, 2005) with different susceptibilities for microbial degradation (Mundt et al, 2003). When chemical mixtures such as tar oil compounds enter the environment, substrate interactions can take place and influence the microbial biodegradation.…”