Abstract
Comparative evaluation was carried out for natural abundance and background levels of cadmium in rice grains produced on the different type of farm fields in Kanto district using flameless atomic absorption spectrophotometry. Rices from Hojo field at foot of the Mount Tsukuba gave narrow range of the lowest cadmium levels between 2.4 and 14.8 ppb and this may consistent with natural abundance level. The rices from polluted area showed wide range of the highest level between 85 and 1, 480 ppb. Cadmium level in other rice samples was distributedbetween these two, the natural abundance and pollution level, sometimes overlapping with the ebge of both, for example 6.6-182 ppb for rices from fields located near town, 7.3-301 in great river basin, 6.5-42.3 in lake shore, and 3.2-56.3 in mountain and hill area, respectively. These evidences probablly suggest that natural abundance of cadmium in rice would correspond to below or around 10 ppb, and that wide range of cadmium levels up to 300 ppb detected in rice from farm fields near town and great river basin would reflect some additional cadmium by background enrichment under intensive humanimpact in Japan.
