Cadmium in induced hair of the rat and its relation to the level in the diet and in the major organs during long-term exposure to cadmium in the subtoxic and toxic range.

Induced hair of the rat was used to examine the suitability of hair analysis as an indicator of cadmium ingestion and for assessing its content in the kidneys or the liver. At an exposure to 3 mg per litre drinking water the transfer to hair exhibited a widely irregular fluctuation during the 50 weeks of the experiment, with a mean which was only slightly higher than that of the 'unexposed' controls. The content in the liver increased at the beginning and attained a steady state within 3 weeks, that in the kidneys increased up to the end of the experiment. The content in the heart and the pancreas behaved similarly to that in the kidneys, that in the brain similarly to that in the liver. At an exposure of 300 mg per litre drinking water the amount of cadmium in hair was significantly higher than that in the unexposed controls and the scatter relative to the mean was smaller than at the low exposure level. The content in the liver increased until the end of the experiment, while that in the kidneys exhibited an inflection after 20 weeks, indicating renal dysfunction. After the onset of renal dysfunction the transfer to hair showed an upward trend. The ultimate cadmium content relation was liver > kidneys > adrenals and pancreas > heart > forebrain. None of them attained steady state within the 50 weeks of exposure. The correlation between cadmium content in hair and that in the various organs was poor, especially at the low exposure level. The findings in the rat suggest that the capability of hair analysis in its application in man for assessing the uptake of cadmium into the body or its burden in the organs in individual persons is limited, especially at low levels of exposure and in cases of discontinued exposure. The 'critical concentration' of cadmium in the kidney cortex of the rat was found in the same range as in man