Evolution of fluoride concentrations in cattle and grass following a volcanic eruption.

This study determined fluoride concentrations of forage, water and bovine serum 2-y after the cessation of a volcanic eruption. Three farms within the polluted area were selected, and water and green grass were collected from April 1990 to February 1992. Samples of hay were collected twice from each farm. Five cows exposed during the 13-mo eruption and 6 young bulls not exposed during the volcanic eruption had blood collected monthly or bimonthly. Serum fluoride concentrations and alkaline phosphatase activities were determined and dental conditions observed in all animals. Grass fluoride remained low except during spring of the second year; high fluoride was in the hay. Serum fluoride of the cows remained near acceptable reference values, although some cows had higher values; serum fluoride of the bulls markedly increased during the spring of the second year. Severe incisor attrition occurred in the cows, while the young bulls had less severely eroded teeth.