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(41-22) Invivo metabolism and organ distribution of a branched 14C-nonylphenol isomer in the pond snail, Lymnaea stagnalis (L.). Lalah, Joseph1,2, Severin, Gabriele*,1, Schramm, Karl-Werner1, Lenoir, Dieter1, Henkelmann, Bernhard1, Behechti, Akbar1, Günther, Klaus3, Kettrup, Antonius, 1 GSF-National Research Center for Environment and Health, Neuherberg, Germany2 Maseno University, Maseno, Kenya3 Forschungszentrum Jülich, Jülich, Germany ABSTRACT- The branched isomers of p-nonylphenol (NP) are perceived to be more resistant to biodegradation in aquatic environments as well as to have more estrogen-like toxicity than the straight chain isomers. By use of GC-MS, some of them have been identified to and found to exist in higher concentrations in the isomeric compound mixture than the straight chain isomers. The investigations of the distribution and metabolism of these branched isomers in aquatic organisms are therefore considered to be important in understanding the mechanisms of toxicity of NP. A single tertiary isomer of NP, 4(3′-,6′-dimethyl-3′-heptyl)-phenol, was synthesized in the laboratory and used in in vivo studies of its organ distribution and metabolism in Lymnaea stagnalis L., following a constant exposure to 14C-NP isomer in water over a period of 8 days at an average exposure concentration of 105 ppb. The results obtained clearly showed the transfer and bioconcentration of the isomer residues in various internal organs of Lymnaea after uptake in water and food. Analysis of the extracts of organ tissues and faeces by HPLC and GC-MS after digestion with Pankreatin/ Key words: nonylphenol, lymnaea stagnalis, metabolism, 14C radiolabeled isomer |
-glucuronidase and nitric acid, respectively, showed that the isomer was metabolized by conjugation to glucuronic acid and hydroxylation to a catechol. The findings from these studies as well as their implications in the biotransformation and estrogenicity of nonylphenol in Lymnaea stagnalis L. will be discussed.