Bioconcentration and biotransformation of [¹⁴C]methoxychlor in the brackish water bivalve Corbicula japonica

Abstract

1. To obtain basic information on the metabolic fate of xenobiotics in the brackish water, bivalve Corbicula japonica, bioconcentration and biotransformation experiments were performed using methoxychlor (MXC) as a model compound. Bivalves were exposed to [ring-U-¹⁴C]MXC (10 µg L⁻1) for 28 days under semi-static conditions followed by a 14-day depuration phase.

2. The ¹⁴C concentration in the bivalves rapidly increased and reached a steady state after exposure for 7 days (BCFss = 2010); however, it rapidly decreased with a half-life of 2.2 days in the depuration phase.

3. Mono- and bis-demethylated MXC, and their corresponding sulphate conjugates, were identified as minor metabolites. No glycoside conjugates (including glucuronide and glucoside) were detected.

4. Despite this biotransformation system, bivalves were found to excrete retained MXC mostly unchanged although its relatively hydrophobic nature.

Keywords::

• Methoxychlor
• metabolism
• bioconcentration
• biotransformation

Acknowledgments

The authors wish to thank Yoshiki Wakasone for his advice, and Hiromi Masuda and Maiko Kameshiro for excellent technical assistance.

Declaration of interest

The authors report no conflicts of interest.