Introduction: Since the beginning of the XXth there has been a constant increase in fluoride (F-) emissions into the environment, mainly due to the development of industry, the fluoridation of drinking water, and the widespread use of toothpaste containing fluoride. All these factors have resulted in an intensive accumulation of F- in the bodies of vertebrates, mainly in their bones. It is therefore reasonable to estimate the F- concentration in humans and other long-lived mammals. Accordingly, ecotoxicologists worldwide have looked for mammalian species that may serve as good bioindicators of environmental fluoride pollution. In contrast to ungulates, long-lived domestic mammals and wild carnivores have rarely been used for this purpose (including the dog, fox and raccoon dog). The main aims of this study were to: 1) investigate F- concentrations in bones obtained from humans, dog, fox and raccoon dog from northwestern Poland, 2) perform intra- and inter-specific comparisons of F- concentrations in the studied mammalian bones against the background of environmental and living conditions, 3) examine the relationship between concentrations of F- in bones and the age or age category of the studied mammals.
Material and methods: The study material comprised bones of the hip joint obtained from 36 patients who underwent hip replacement in Szczecin, 43 dogs from Szczecin veterinary clinics, 32 foxes and 18 raccoon dogs provided by hunters, with the whole test material consisting of 129 samples. The indications of F- (using potentiometry with Thermo Orion ion-selective electrodes) were performed in triplicate. The F- concentration was expressed on a dry weight basis.
Results: Interspecific analysis showed that the largest number of differences in the concentrations of F- were between the fox and raccoon, and then between the dog and fox, and then between the dog and the wild canids (foxes and raccoon dogs together). Close statistically significant differences were also found between the samples from humans and the fox, and also between human and dog bones. There were no statistically significant differences in the concentrations of F- between humans and raccoons, humans and canids (dog, fox, raccoon dog together), and between dogs and raccoon dogs.
Conclusions: Domesticated and wild canids are good bioindicators of environmental levels of fluoride, because they reflect the concentration of fluoride in bones observed in humans who lived in a similar area.