ABSTRACT
Objective To evaluate disinfection efficacy of slightly acidic hypochlorous water (SAHW) on object surfaces of hemodialysis room. Methods 30 dialysis units in the hemodialysis room were dividea into two groups (trichloroisocyanuric acid group and SAHW group) by random number table method, 15 dialysis units in each group. Trichloroisocyanuric acid group disinfected object surface of each hemodialysis unit with trichloroisocyanuric acid containing 500 mg/L available chlorine, and SAHW group disinfected with SAHW. The colony counts on object surface after 4 hour disinfection were detected, the qualified status and killing of multidrug-resistant organisms (MDROs) between two disinfection methods were compared. Results After bedrails, screens of dialysis machine, and knobs of dialysis machine were disinfected by trichloroisocyanuric acid containing 500 mg/L available chlorine and SAHW respectively, the qualified rates of trichloroisocyanuric acid group were 90.00％, 80.00％, and 90.00％ respectively. SAHW group were 100.00％, 96.67％, and 100. 00％ respectively, difference was not significant between two disinfection methods(both P＞0.05). SAHW disinfection testing showed that the killing rates of SAHW to four MDROs were both 100％. Conclusion Disinfection efficacy of SAHW is the same as that of trichloroisocyanuric acid containing 500 mg/L available chlorine, and has high killing effect on the common MDROs in the hemodialysis room.
ABSTRACT
OBJECTIVE To investigate the developmental toxicity of a new disinfectant trichloroiso-cyanuric acid (TCCA) on zebrafish embryos and larvae. METHODS Zebrafish embryos of 2 h post fertilization (hpf) were exposed to TCCA:①The embryos were exposed to a culture medium containing TCCA 0, 50, 100, 150, 200, 250 and 300 mg·L-1 for 48 h before 50%lethal concentration (LC50) was calcu-lated. ② The embryos were exposed to a culture medium containing TCCA 0, 10.4, 20.8 and 41.7 mg · L-1 for 96 h. The mortality, malformation rate and heart rate of embryos and larvae were measured at 48, 72 and 96 h after TCCA exposure. The expression of superoxide dismutase (SOD) was detected at 2, 4 and 6 h after TCCA exposure. The pathological changes in the head of zebrafish larvae were observed 7 d after exposure by HE staining. RESULTS LC50 of 48 h after TCCA exposure was 166.9 mg · L-1. Compared with normal control group, the mortality and malformation rate of zebrafish embryos were significantly increased (P<0.05) in TCCA 41.7 mg · L-1 group, but the heart rate was decreased significantly (P<0.05) in each dose of TCCA group at 96 h after TCCA exposure. At 72 h after TCCA exposure, the mortality rate of zebrafish embryos was significantly increased (P<0.05) in TCCA 41.7 mg·L-1 group, the malformation rate of zebrafish embryos was increased (P<0.05) and the heart rate of zebrafish embryos was decreased (P<0.05) in 20.8 and 41.7 mg · L-1 groups. At 48 h after TCCA exposure, the heart rate of zebrafish embryos was decreased significantly (P<0.05) in 41.7 mg · L-1 group. The SOD activity of zebrafish embryos in 20.8 and 41.7 mg · L-1 groups was significantly lower than that of control group (P<0.05). At 7 d after exposure, the brain and ocular space of larvae were enlarged and the ocular retina layers were not obvious in any dose of TCCA groups. CONCLUSION TCCA has toxic effect on zebrafish embryonic development, which can down-regulate SOD activity in the early developmental stage of embryos and damage the retina tissue of larvae.
ABSTRACT
TCCA containing a high amount of effective chlorine is an organic disinfectant for drinking water. A small amount of it has satisfactory effect with less odour and color, It is stable in storage.The factors which effect disinfection are less.It is suitable for the disinfection of various kinds of water sources. The laboratory experiment and field investigation showed that the rate of killing bacteria in water was 99.99% when its concentration was 1.4-3.4 mg/1.the temperature was 5?to 30℃, the pH value was 5-9, the disinfecting time was 10 to 30 minutes.There was an exception of the experimental group number 7 and 9 which showed the rate of killing bacteria was 99. 94%. The toxicity of TCCA is low, the disinfectant effect is much better when it is used with SM-92 coagulant.