Fluoride in the bone and diet of fin whales, Balaenoptera physalus

Bone samples were taken from fin whales Balaenoptera physalus from the North Atlantic to examine the relationship between fluoride concentration in skeletal tissue and age, sex, body length and anatomic location. By the use of an ion-selective electrode, the fluoride concentration in these samples were found to be higher than that normally occurring in any mammalian species, ranging from 4340 to 18 570 ppm. The positive correlation observed with age, along with high fluoride concentrations found in krill taken from the stomachs of these whales, indicated a probable bioaccumulation of fluoride from dietary sources. These results confirmed and extended earlier findings that bone tissue in fin whales naturally contains very high concentrations of fluoride and indicate that this baleen whale is tolerant to a significant extent of the high fluoride concentrations found in krill.