Critical concentration of cadmium in kidney cortex of humans exposed to environmental cadmium.

Cadmium (Cd) was determined in kidney cortex and liver of 173 autopsied Japanese. Subjects consisted of 51 persons from Cd-polluted areas ages between 61-94 years and 122 controls ages between 3-90 years. The mean Cd concentrations for the Cd-polluted group were 35.2 micrograms/g wet wt for kidney cortex and 66.7 micrograms/g wet wt for liver. Corresponding values for the control group aged over 60 were 90.1 and 10.7, respectively. Both liver and kidney cortex Cd were analyzed for 127 subjects (41 Cd-polluted and 86 control subjects). The kidney cortex concentration tended to increase linearly with increasing liver concentrations up to approximately 20 micrograms/g of liver Cd; above this value there was no further increase in kidney cortex level. Only three persons showed kidney cortex Cd levels above 200 micrograms/g. The lowest liver Cd levels of the Cd-polluted subjects with renal damage were around 30 micrograms/g. The critical level of kidney cortex Cd may exist below 200 micrograms/g in humans exposed to environmental Cd. The corresponding value for the liver may be below 30 micrograms/g wet wt.