Occurrence of musk xylene and musk ketone metabolites in the aquatic environment

Abstract Quantification of musk xylene (MX) and musk ketone (MK) was for the first time achieved in aquatic environmental samples simultaneously with their transformation products 4-amino-MX, 2-amino-MX, and 2-amino-MK at a ng/L level using liquid-liquid extraction and subsequent GC-MS and GC with AFID detection. Thus, the transformation of nitro musks to the corresponding amines could be studied in samples of the sewage plant Hamburg and of the river Elbe. In the influent of the sewage treatment plant concentrations of 150 and 550 ng/L were found for MX and MK, respectively, while in the effluent the corresponding values were 10 and 6 ng/L. The amino derivatives as transformation products were not detectable in the influent samples, however, values of 10 ng/L (2-amino-MX), 34 ng/L (4-amino-MX), and 250 ng/L (2-amino-MK) were found in the effluent samples. These latter concentrations were 4 to 40 times higher than the parent compounds. The simultaneous decrease in the nitro musk concentrations and the increase in the amino derivatives suggest that, besides adsorption at the sludge, this transformation pathway plays an important role. In the Elbe river the concentrations of 4-amino-MX attained at least 3 to 10 fold higher values (1 – 9 ng/L) than the parent compound, while 2-amino-MK exhibited a concentration of 7 ng/L. These results suggest that monitoring programmes as well as risk assessments of nitro musks in aquatic ecosystems should include the transformation products such as the amino derivatives investigated herein.