Abstract
The organic lead added to gasoline to maintain its octane value, organochlorine agrochemical DDT widely used throughout the world were banned in early '70s in Japan, and the human exposure to them has been gradually decreased these decades. The atmospheric nuclear detonation tests, which were heavily practiced through' 60s, were also regulated substantially in early'70s, and the radioactive fallouts like Sr-90 and Cs-137 were reduced these decades. These environmental micropollutants were examined for their environmental fates, human exposures and human health risks in the last half century, by using the environmental risk evaluation model. Main results obtained in this study can be summarized as follows;
(1) Lead concentration in ambient air, DDT and radionuclides in an environment were reduced right after thereduction of their release to an environment, and the related health risks have also been reduced.
(2) The unleaded gasoline policy was evaluated to be effective for reduction of the potential health risks especially in the population group with the larger lead exposure. The base line lead exposure was not reduced because of the rather constant lead exposure through dietary pathway.
(3) The lifespan cancer induction risk of the reference Japanese due to the DDT was evaluated to be larger than 10-5 level for people born before 1970, but for people born after 1970 the risk has been reduced to less than 10-5 level by the ban of DDT use in early 1970's.
(4) The lifespan cancer induction risk of the reference Japanese due to the radioactive fallout Sr-90 and Cs-137 was evaluated to be10
-6 level for people born before 1960, but for people born after 1960 the risk has been reduced to less than 10-6 level by the ban of the atmospheric nuclear detonation tests.
