Assessment of azaarenes and azaarones (oxidized azaarene derivatives) in the Dutch coastal zone of the North Sea

“Azaarones (oxidized derivatives of azaarenes) is a group of newly emerging chemical compounds. Little is known about their occurrence in the aquatic environment. Azaarenes are polycyclic aromatic heterocyclic compounds containing one nitrogen atom in one of the aromatic rings. The (photo) oxidized metabolites of the azaarenes are often more toxic than the parent compound. For the first time the concentration of seven azaarenes and seven primary metabolites have been measured in the surface sediments (fraction<63microm) of the Dutch coastal zone of the North Sea. Samples collected in 2000 and 2001 were analyzed using a newly developed method to determine the contents of azaarenes and azaarones simultaneously in a single GC-MS run. The concentrations of acridine, benz[a]acridine, benz[c]acridine and 5,6-benzoquinoline varied between 10-63, 3.9-25, 3.3-11 and 3.98-10.84ngg(-1), respectively. Concentrations of 7,8-benzoquinoline and phenanthridine were below the limit of detection. 2-Hydroxyquinoline and 5-hydroxyquinoline, probably metabolites of quinoline, were present in relatively high concentrations: 7.4-949 and 11-188ngg(-1). A gradient was observed with highest concentrations of the sum of azaarenes and the sum of the concentration of their metabolites close to the coast and lower concentrations further offshore. The concentrations of azaarenes and their metabolites are in the same order of magnitude as those found to induce phototoxicity to algae. The concentrations of mineral oil and PAHs in the surface sediments of the Dutch coastal zone of the North Sea were, at most locations, above the Dutch chemical targets for environmental protection. Spatial distribution of PAHs and mineral oil were slightly different from those of azaarenes and transformation products. Simultaneous GC-MS for azaarenes and their degradation products is possible but extraction/clean up can be further improved. Azaarenes as well as their primary metabolic products are present in the marine environment. In sediments the cumulative concentrations of transformation products amount to about four times the cumulative concentrations of the azaarenes. In conclusion, azaarenes and their metabolites constitute a new group of emerging polycyclic aromatic compounds which need more attention in the future." Copyright © 2009 Elsevier Ltd. All rights reserved. (Citaat: Voogt, W.P. de, Laane, R.W.P.M. - Assessment of azaarenes and azaarones (oxidized azaarene derivatives) in the Dutch coastal zone of the North Sea - Chemosphere 76 (2009)8, p.1067-1074)