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COMPARATIVE SUBCHRONIC TOXICITY STUDIES OF THREE DISINFECTANTS
Citation:
Daniel, F., L. Condie, M. Robinson, J. Stober, R. York, G. Olson, AND S. Wang. COMPARATIVE SUBCHRONIC TOXICITY STUDIES OF THREE DISINFECTANTS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-92/122 (NTIS PB92164920), 1990.
Description:
In separate subchronic toxicity studies, male and female Sprague-Dawley rats received three water disinfectants in the drinking water for 90 consecutive days. he treatment levels were 25 mg/L, 100 mg/L, 175 mg/L and 250 mg/L for chlorine, and 25 mg/L, 50 mg/L, 100 mg/L and 200 mg/L for both monochloramine and chlorine dioxide. ontrols received carbonated (ph buffered) drinking water. ater consumption for all three compounds decreased in a dose-related fashion with increasing concentration of disinfectant, most likely due to unpalatability. one of the disinfectants caused premature deaths in any concentration evaluated. he highest dose of chlorine tested (250 mg/L) was considered to be a no observable adverse effect level (NOAEL) as no body weight, absolute or relative organ weight, hematological, clinical or histopathological changes were observed in either sex. he monochloramine produced both decreased body and organ weights in both sexes (heart, liver, lung and spleen in males; liver, spleen and thymus in females) and a small decrease in red blood cell count and serum calcium in males, 200 mg/L. hus, this concentration (circa 9-12 mg/kg-day) was considered the lowest observable effect level (LOAEL), while 100 mg/L was designated the NOAEL. onochloramine produced no histopathological evidence of toxicity in either sex. hlorine dioxide produced dose-related decreases in body and organ (in the liver at 50 mg/L in males; in the spleen at 25 mg/L in females) weights. here were no observed hematological changes associated with chlorine dioxide treatment, but significant reductions in creatinine in both sexes and in serum enzymes LDH and AST in males were indiced at the high concentration (circa 12-15 mg/kg-day). he most significant toxic effect of chlorine dioxide was the induction, at all concentrations, of nasal lesions (goblet cell hyperplasia and subacute inflammation). hese lesions were observed in both sexes. hus, our study suggests that a NOAEL was not found for chlorine dioxide and a LOAEL at 25 mg/L is indicated.