Studies on Metabolism of Triclosan, a Disinfectant, as Medical Waste by Activated Sludges

采用吸氧法研究了三氯生（2,4,4′-三氯-2′-羟基二苯醚）对活性污泥的影响。结果表明，该消毒剂的最大无反应浓度为20 mg/l， 50%浓度的抑制率为50 mg/l。除六氯苯的最大非活性浓度为6 mg/l外，三氯生的毒性比其他消毒剂强。滨松大学医学院医疗废水中三氯生浓度在几百ng/l到几mug/l之间。我们已经报道了我校排放的医疗废水中氯己定和苄索氯铵的浓度分别为几百马克杯/升和几毫克/升。很明显，这种化合物的值明显低于两种消毒剂。结果表明，与其他化合物相比，该化合物的使用量较低。采用新开发的质粒破碎法对我校医疗废水处理厂的原水、生物处理废水和终处理水中的三氯生浓度也未进行检测。可以假定该化合物被活性污泥吸附或分解。三氯生在活性污泥上的代谢假定如下：(1) 2′-羟基自由基的鉴定或共轭；(2)苯环的过氧化反应；(3)2,4,4′-氯的羟基化反应。通过高压液相色谱和质谱分析，发现三氯生的代谢产物为2′-羟基自由基的甲基化和2,4,4′-氯的任意一次脱氯。

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.