All water analyses were performed by Unilab Analyse AS
(Tromsø, Norway). The water samples from the crude oil
experiment were analyzed for the 16 Environmental Protection
Agency (EPA) priority PAHs plus naphthalenes, phenanthrenes
and dibenzothiophenes (NPD). Water samples from the pyrene
experiment were analyzed for pyrene only. Briefly, an internal
standard was added to the water samples that were extracted
with dichloromethane. Extracts were analyzed by Gas Chromatograph/
Mass Spectrometry (GC/MS) (Hewlett-Packard/Agilent
Technologies). The quantification of individual components was
related to the internal standard. When concentrations were measured
to be below the level of quantification (LOQ), 1/2 LOQ was
used as concentration value.