Concentration and Bioaccumulation of Cyanobacterial Bioactive and Odorous Metabolites Occurred in a Large, Shallow Chinese Lake

The distributions of cyanobacterial bioactive and odorous metabolites were investigated in the fifth largest lake in China in the fishing season 2012. The highest microcystins (MCs) concentration in water reached 3.4 µg L−1. A high β-ionone concentration reached 35.6 ng L−1 in water. Mean MCs concentration in muscle was highest in omnivorous Carassius auratus (20.9 ng g−1 dry weight), followed by phytoplanktivorous Hypophthalmichthys molitrix (7.4 ng g−1 DW) and carnivorous Coilia ectenes (3.0 ng g−1 DW). The maximum off-flavor concentrations kept 9.5 µg kg−1 wet weight for geosmin (C. auratus), 5.5 µg kg−1 WW for β-cyclocitral (C. ectenes) and 25.5 µg kg−1 WW for β-ionone (C. ectenes). Positive correlation was found between the off-flavor and fat contents in C. ectenes. To be different with MCs, β-cyclocitral content was highest in fore-gut contents (87.6 µg kg−1 WW) in H. molitrix. It should not be reliable to predict odorous compounds level in fish muscle by only measuring the off-flavor in lake water only.