Aerobic degradation of a hydrocarbon mixture in natural uncontaminated potting soil by indigenous microorganisms at 20 degrees C and 6 degrees C

A hydrocarbon mixture containing p-xylene, naphthalene, Br-naphthalene and straight aliphatic hydrocarbons (C-14 to C-17) was aerobically degraded wit hout lag phase by a natural uncontaminated potting soil at 20 degrees C and 6 degrees C. Starting concentrations were approximately 46 ppm for the aro matic and 13 ppm for the aliphatic compounds. All aliphatic hydrocarbons we re degraded within 5 days at 20 degrees C, to levels below detection (ppb l evels) but only down to 10% of initial concentration at 6 degrees C. Naphth alene was degraded within 12 days at 20 degrees C and unaffected at 6 degre es C. At 20 degrees C p-xylene was degraded within 20 days, but no degradat ion occurred at 6 degrees C. Br-naphthalene was only removed down to 30% of initial concentration at 20 degrees C, with no significant effect at 6 deg rees C. The biodegradation was monitored with head space solid-phase microe xtraction and chromatography-mass spectrometry.