Inactivation of Heterotrophic Bacteria in Well Water Using ZVI, TiO2 and ZnO Nanoparticles

Background & Aims of the Study: The heterotrophic bacteria are widely used as a water microbial pollution index for drinking water. The aim of this study was to investigate the effect of metallic nanoparticles such as Zero Valent Iron (ZVI), Titanium dioxide (TiO2) and Zinc oxide (ZnO) on Heterotrophic Bacteria inactivation in well water. Materials & Methods: We performed an experimental-laboratory study that the effect of nanoparticles type Zero valent iron (ZVI), Titanium Dioxide (TiO2) and Zinc oxide (ZnO)) in constant contact time (30 min) and nanoparticles dose (1 g/L) was investigated on heterotrophic bacteria inactivation. Results: The results showed that TiO2 was detected more effective than ZnO and ZVI. The HPC inactivation after 30 min of retention time by TiO2, ZnO and ZVI nanoparticles were 71.5, 50 and 36.4 as percent, respectively. The maximum bacteria inactivation was 98.82% in the presence of TiO2 nanoparticles. Conclusions: It is concluded that nanoparticles used in this study could be effectively used to increase the efficiency of removing heterotrophic bacteria from water and can be considered for microorganisms’ inactivation

An Epidemiological Study of Carbon Monoxide Poisoning Rate and a Comparison with Other Poisonings Recorded in Mazandaran Department of Forensic Medicine, 2009-2011

Background: Carbon monoxide is an odorless, colorless and poisonous gas. Since there is currently no information on the prevalence of carbon monoxide poisoning in Mazandaran, this study aimed to investigate the prevalence of carbon monoxide poisoning and compare its prevalence with other poisonings recorded in Mazandaran Department of Forensic Medicine, from 2009 to 2011. Methods: This is a descriptive-analytical study, in which the information was received from Mazandaran Department of Forensic Medicine. Results: Among the 2446 human deaths in 2009, 2010, 2011, 237 deaths were due to poisoning and 27 (11.4%) were due to carbon monoxide poisoning, which ranked third after narcotic and Aluminum phosphide intoxication. Poisoning in males was 1.7 times more than females. Co was the most common cause of deaths among people aged 21 to 30 years. Conclusion: Considering the fact that in most cases of poisoning deaths caused by CO (silent killer) come by quietly and in a hidden manner, CO actually makes any defense and escape impossible for the person and despite seeing the shadow of death, that person will inevitably surrender and will be defeated. Therefore, it is necessary to educate and inform the public through media and educational institutions about the risks and sources of CO poisoning