From the viewpoint of environmental pollution, heavy metals have been known to produce serious health problems.
The potential exposure of the metals is increased progressively with the industrial development. Human and other organisms were exposed to various metals in many ways. Especially cadmium and lead are very important in heavy metal poisonings. Simultaneous exposure to cadmium and lead is highly probable due to common environmental sources of exposure. This can result in effects different from those produced by a single metal by itself. Information. on this subject is rather limited.
To clarify the effects on cadmium-lead interaction on rat organs when exposed to the single chemical and combined chemicals, a study was carried out.
Eighty-five mature rats of Sprague-Dawley strain were divided into the control group and the experimental groups.
The three study groups were given the chemical compounds through peritoneum injection every day for fourteen days.
After the series of injection and breeding of twenty-five days, the rats were killed and examined. Organs were removed and analyzed for cadmium and lead amounts.
The amounts of calcium and phosphorus were also measured in femurs. The atomic absorption apparatus for the metals and the spectrophotometer method for phosphorus were employed.
Their effects on the body weight changes and organ-body weight ratio were also observed in comparison to control group.
The results obtained were as follows;
1. Body weight gains of the rats injected with cadmium, the rats with cadmium and lead and the rats with lead were depressed respectively. Difference in growth between cadmium group and control group was almost not observed. The growth rates of the lead group and cadmium and lead group were inferior to that of the control group.
2. The weight ratios of organs to body weight were compared and those of liver, kidney, lung and -spleen were depressed to compare with those of control group. In contrast, the ratio of femur increased in all study groups.
3. The remarkable accumulations of cadmium and lead were observed in kidneys and additive actions -of lead to cadmium was observed in liver and kidneys, and those of cadmium to lead were marked only in kidneys.
4. Cadmium was not so much accumulated in femurs, but a large amount of lead was accumulated in femurs. The additive actions of the lead in femurs were conspicuous but those of cadmium were not significant.
5. The amount of calcium and phosphorus in femurs was lowest in cadmium group. In contrast to that, the amount of calcium and phosphorus in combined group and lead group increased respectively.
The additive actions between two metals on metabolism of calcium and phosphorus were relatively low.
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