Abstract
The content of fluorine was determined in agricultural foodstuffs by the zirconium-Eriochrome cyanin R method and the thorium nitrate volumetry.
Rice samples had contained 1.51ppm of fluorine about 100 years ago in Japan. Rice samples in 1958 and 1960 contained 5.73 and 13.95ppm of fluorine, respectively. The contents of fluorine in other agricultural foodstuffs in 1965 were higher than those in 1958. A possible reason for this increase of fluorine content in foods in recent years may reside in the application of chemical fertilizers, especially phosphates.
Much fluorine was found in tea leaves, umbelliferae and pulses. Among many kinds of fruits in Japan, apples showed the highest content.
In vegetative foods, seeds contained more fluorine than edible parts. In Welsh onion, the content of fluorine in green portion was higher than that in white portion. The fluorine content of leaf stalk was generally lower compared with that of leaf blade.
