1. Department of Ecotoxicology, DHI Water & Environment, 11 Agern Allé, DK-2970 Hørsholm, Denmark, Institute of Food Safety and Nutrition, Danish Veterinary and Food Administration, 19 Mørkhøj Bygade, DK-2860 Søborg, Denmark, and Danish Environmental Protection Agency, Strandgade 29, DK-1401 Copenhagen K, Denmark