Accumulation of naphthalene degradation products in the supernatant was accompanied by a decrease in pH. Actually, the major metabolite was salicylic acid, as determined by gas chromatography-mass spectrometry. As expected, an increase in the apparent aqueous solubility of naphthalene was observed when concentrations of glycolipids exceeded the critical micelle concentration(which is indicated by the lowered surface tension).Because of its volatility, the actual concentration of solubilized naphthalene was probably slightly higher than indicated by the data obtained. Bacterial degradation of naphthalene was not directly quantified because of its volatility and utilization of very high concentrations (20 g/liter). Degradation of naphthalene is therefore indirectly shown by the accumulation of glycolipids
and metabolic intermediates.