[Study on secular changes of cadmium concentration accumulated in main organs of Japanese].

With the development of the mining and manufacturing industries and the petrochemical industry, cadmium (Cd) has been used not only for metal products but also petroleum products. Recently, environmental pollution due to waste fluids and gases from factories using cadmium and also domestic waste materials has become a cause for concern. In this connection, studies on the accumulated levels of Cd in the human body, its age-distribution in the general population and its secular changes during the last decade would be useful for clarifying the degree of contamination in the human body and providing an index which could be used as a basis for preventive measures against environmental pollution. For this purpose, the levels of Cd accumulated in main organs of the human body were determined using forensic data 3 times at 5-year intervals starting in 1976. The age intervals starting in 1976. The age group having the highest Cd level was 50-59 years, old and the mean weights of Cd per wet weight of heart, liver and kidney were 0.421, 2,984 and 56.43 micrograms/g, respectively. Each of these organs in babies less than a year old exhibited lower Cd levels, but teenagers had levels close to those in adult. However, the level in each organ was lower in individuals over 60 years old. 4 distinct age-related increase in the level of Cd was found only in the kidney. The levels of accumulated Cd in the liver and kidney showed a rise during the last 10 years from 2.358 to 5.568 micrograms/g and from 43.95 to 73.47 micrograms/g, respectively, whereas the Cd level in the heart has remained about the same, i.e. from 0.207 to 0.181 micrograms/g.