The report represents the results of a comprehensive series of toxicological studies designed to evaluate the health effects of the application of recycled water for drinking purposes. Water was prepared in a highly advanced domestic sewerage pilot plant. Some 400,000 liters of the finished water were concentrated down to a volume of 200 liters with a total organic carbon content of 700 mg/l. This concentrate was incorporated into a gel-type diet which was fed to mice. A total of 900 animals was included in the experimental program, which extended to 150 days. The mice were tested for growth, food intake, mutagenicity, mortality, blood physiology and biochemistry, and liver and nervous system functions. Ten tissues were screened for pathological effects. Only marginal changes were demonstrated in these areas. In a second series of experiments, rodent and human cells were tested in vitro for general toxicity, mutagenicity, and carcinogenicity. Results for all three effects in the tissue cultures were positive. These effects were significantly increased by the presence of a liver activation system. These results show that exposure for a limited time (20% of a lifespan) to the concentrated, recycled water (about 100-1000 times present human exposure) does not lead to physiological changes in mice. On the other hand, the positive results from the mutagenicity and carcinogenicity studies in tissue culture indicate a need for more studies in this area.

Report submitted by Gulf South Research Institute under contract no. 68-03-2464. Issued Dec. 1978. Includes bibliographical references.