Toxicity of Heavy Water. ∗

Abstract

The following experiments were performed in an effort to determine whether or not the newly recognized substance, heavy water (deuterium oxide) possesses toxic properties. Water containing approximately 20% deuterium oxide was prepared electrolytically and its action tested on rabbit leucocytes and bacteria. Experiments are now being done testing heavy water in more concentrated form up to 100%.

Experiment I—Rabbit leucocytes. One drop of a 24-hour aleurinate broth exudate, freshly removed from the pleural cavity of a rabbit, was added to 2 cc. of a modified Tyrode solution containing 18% heavy water and 1/10,000 neutral red. The Tyrode solution, which was buffered at pH 6.6, had 10% of its salts replaced by NH₄Cl. Two hanging drops and one spread preparation, sealed with vaseline-paraffin mixture, were incubated at 37°C. and observed under the microscope. A control series was prepared with triple distilled water.

The viability of the leucocytes was followed. After one hour an occasional dead cell could be seen. In 8 hours 10% were dead; in 16 hours 50%, and in 24 hours about 75% were dead. There were no significant differences between leucocytes in the heavy water solution and control ordinary water preparations.

Experiment 2—Growth of Staphylococcus. A. A minute amount of an 18-hour broth culture of hemolytic Staphylococcus aureus was added to a drop of 20% heavy water. The drop was divided into 3 parts which were sealed on sterile cover slip hanging drops. These were cultured on blood agar plates after 6, 24 and 48 hours respectively. There was no inhibition of growth.

B. A drop of 20% heavy water was placed in the center of a blood agar plate freshly streaked with the organism used in A. No effect was noted during a period of 4 days.