| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1993: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1992: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
Effects of triclosan (2,4,4'-Trichloro-2'-hydroxydiphenyl ether) on activated sludges were investigated using an oxygen up-take method. As the results, the maximum non-reactive concentration of this disinfectant was 20 mg/l, and its inhibition rate 50 % concentration was 50 mg/l. The toxicity of triclosan has stronger than those of other disinfectants, except the maximum non-reactive concentration of hexachlorophene (6 mg/l).
Triclosan concentrations in medical waste water from Hamamatsu University School of Medicine were within the range of several hundred ng/l to several mug/l. We have already reported that the concentrations of chlorhexidine and benzethonium chloride in medical waste water discharged from our university were several hundred mug/l and several mg/l, respectively. It is clear that the values of this compound are remarkably lower than both disinfectants. The results are reflected that the used amount of this compound is lower compared with those of others.
The concentrations of triclosan in raw water, biological treatment waster and final treatment water from the medical waste water treatment plant of our university were not also detected by new mass fragmentography developed. It can be presumed that this compound is adsorbed or decomposed by activated sludges.
The metabolism of triclosan on activated sludges is presupposed as follows ; (1) the estification or conjugation of 2'-hydroxy radical, (2) the peroxidation of benzene rings, and the hydroxylation, (3) dechlorination of 2,4,4'-chlorine. The metabolites of triclosan were found to be methyl estification of 2'-hydroxy radical and any one dechlorination of 2,4,4'-chlorine by high pressure liquid chromatography and mass fragmentography.
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