1. The University of Tennessee, College of Veterinary Medicine, 2407 River Drive, Knoxville, Tennessee 37996-4543, School of Pharmacy and Chemistry, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, England, and Department of Chemical Ecotoxicology, UFZ Centre for Environmental Research, Leipzig-Halle, Permoserstrasse 15, D-04318, Germany