ABSTRACT
Objective To observe the efficacy of ozone in the inactivation of f2 phage in water. Methods The concentration of ozone in water was measured by iodometry. During the experiment,the suspension of f2 phage was added in the ozonized water, at 5,15,30 min, the f2 phage inactivation rate was calculated. Results Under the same condition of ventilation,in the range of pH regulated in the drinking water sanitary standard,the effect of pH on the inactivation of f2 phage was not obvious, while the chromaticity of water could remarkably influence the inactivation of f2 phage. Conclusion The higher chromaticity of water can interfere the inactivation of f2 phage in water by ozone.
ABSTRACT
Objective To explore the relationship between trace elements proportion in food and health. Methods 45 mice aged 12 month were randomly divided into 3 groups: control group(n=16) and two experimental groups(n=15).The mice in the experimental groups were given Zn, Li, Fe, Se, Mn, Cu, Co in different proportion by food for 60 days, then all mice were sacrificed, thymus weight, spleen weight, thymus coefficient, spleen coefficient, bone indexes were determined. Results Supplementation of the trace elements in food increased the content of Ca2+ in the bone of the aged mice and proportion variety of trace elements might induce the changes of thymus weight, spleen weight, spleen coefficient and bone indexes. Conclusion The reasonable proportion of trace elements in food could increase the content of bone Ca2+ in aged mice.
ABSTRACT
Objective To evaluate the safety of the levels of fluoride,arsenic and lead in toothpaste and the microbiological index of the toothpaste saled in Tianjin. Methods 60 tubes of toothpaste were sampled from the department stores and shops in Tianjin. The toothpaste samples included 14 tubes of commen toothpaste,18 tubes of medicated toothpaste,28 tubes of toothpaste blended with fluoride. Among 28 tubes of fluoride-adding toothpaste,6 tubes were specially used for children,19 tubes were domestic products for adults,3 tubes were imported for adults. All of the domestic toothpaste sampled were made in more than 10 cities and privinces such as: Tianjin,Beijing,Shanghai,Guangdong,etc. The levels of fluoride in toothpaste were determined by ion selective electrode,arsenic and lead were determined by inductively coupled plasma emission spectroscopy,the microbiological indexes were determined based on GB8372-1995 (toothpaste?雪. Results The contentes of soluble fluoride were 539-877 mg/kg for 5 tubes of fluoride-adding toothpaste used for children, 1 582-1 697 mg/kg for 3 tubes of domestic fluoride-adding toothpaste used for adults. The content of lead in an tubes of imported toothpaste was as high as 43.09 mg/kg,2.9 time the value of the national standard. The total count of bacteria,the count of fecal coliform,Paeruginosa,Staph aureus in 52 tubes of toothpaste sampled met the requirement of the related national standards. Conclusion The sanitary quality of 60 tubes of toothpaste sampled for this study saled in Tianjin was qualified in general,but very few had the sanitary problems in the aspects of fluoride excess in domestic fluoride-adding toothpaste and lead excess in imported toothpaste.