Phenols in rainwater

From July to December 1989 22 rain water samples were collected in Hannover (F.R. Germany) and analyzed for phenol, 2-methylphenol, 3-/4-methylphenol, 2-nitrophenol and 4-nitrophenol by combined gaschromatography/mass spectrometry (GC/MS) using deuterated internal standards for quantitation. Among the non nitrated phenols phenol was the dominant component with a mean concentration of 8.4 myg/l, while the average concentration for the sum of 3- and 4-methylphenol was 2.7 myg/l and that of 2-methylphenol even lower (0.93 myg/l). Among the nitrophenols 4-nitrophenol was by far the dominant component with an average concentration of 6.1 myg/l, while 2-nitrophenol was present only in traces (mean = 0,18 myg/l). There was no significant correlation between the concentrations of the various phenols. Moreover, a dependence on the season was not observed. It is assumed that the very high concentrations of phenols in precipitation is due to their photochemical formation in the atmosphere.