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Processes controlling the distribution and natural attenuation (NA) of phenol, cresols and xylenols released from a former coal-tar distillation plant in a deep Triassic sandstone aquifer are evaluated from vertical profiles along the plume centerline at 130 and 350 m from the site. Up to four groups of contaminants (phenols, mineral acids, NaOH, NaCl) form discrete and overlapping plumes in the aquifer. Their distribution reflects changing source history with releases of contaminants from different locations. Organic contaminant distribution in the aquifer is determined more by site source history than degradation. Contaminant degradation at total organic carbon (TOC) concentrations up to 6500 mg l⁻¹ (7500 mg l⁻¹ total phenolics) is occurring by aerobic respiration NO₃-reduction, Mn(IV)-/Fe(III)-reduction, SO₄-reduction, methanogenesis and fermentation, with the accumulation of inorganic carbon, organic …