THE TOXICITY OF SOME ZIRCONIUM AND THORIUM SALTS IN RATS

¹ College of Medicine, University of Illinois, Chicago, Illinois
² Argonne National Laboratory, Chicago, Illinois

1. The acute toxicity in rats of the citrate and gluconate salts of zirconium and the citrate salt of thorium have been studied. The salts were administered by intraperitoneal injection at frequent intervals for not more than 20 hours in large doses and, in the case of zirconium citrate, in divided doses over a period of two to eight days.

2. The LD₅₀'s and the standard errors for the experiments where the animals received large frequent doses of the above salts were determined.

3. Rats which survived 36 hours following the large frequent doses of the zirconium and thorium salts invariably recovered and exhibited no toxic symptoms 6 months later. No hematologic or histologic effects of zirconium (citrate) were found.

4. As much as 3,600 mgm./kgm. of zirconium (citrate) was tolerated by rats when administered by intraperitoneal injection once daily in doses of 450 mgm./kgm.

We are grateful to Miss Ruth P. Rhoades for carrying out the histological examinations and to Miss Rose Hunter and Mrs. Myrtle Karcher for their valuable services. We are indebted to members of the Biology Division and in particular to Dr. Hermann Lisco and Dr. Miriam Finkle for their advice on technical problems arising during the course of this work.