Marjan Nouri; Amirsalar Montazer Faraj
Abstract
Drinking water is one of the main factors for health maintenance and sustainable development of communities and its quantity and quality are so important. The aim of present study is random sampling of drinking water in 30 regions of Tehran city during 2 months in summer of 2020 to determine physicochemical ...
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Drinking water is one of the main factors for health maintenance and sustainable development of communities and its quantity and quality are so important. The aim of present study is random sampling of drinking water in 30 regions of Tehran city during 2 months in summer of 2020 to determine physicochemical attributes, microbial quantity and heavy metal levels according to national standard guidelines. Tests such as pH, alkalinity, turbidity, electrical conductivity, chloride, nitrite level, total and thermotolerant coliforms, and also heavy metals (arsenic, copper, zinc and lead), were performed in three replications. The pH (6.50 to 7.81), turbidity (0.011 to 2.983 NUT), chloride level (240.42 to 321.34 mg/L) and nitrate value (7.21 to 20.04 mg/L) were in allowable ranges. The phenolphthalein alkalinity was not found and methyl orange alkalinity was detected in the range of 31.54 to 147.22 (mg/L) in samples. The electrical conductivity (1401.7 to 1972.1 μs/cm) and thermotolerant coliforms were found higher than allowable range in some samples. The range of heavy metals was represented by following trend in Tehran: arsenic (0.85 to 15.90 μg/L), cooper (0.04 to 3.38 mg/L), zinc (0.16 to 3.80 mg/L), lead (0.001 to 0.031 mg/L) and some ranges were not within the national standard guidelines. The present study illustrated that quality of drinking water was in line with World Health Organization, while microbial quantity, electrical conductivity and some impurities (Cu and Pb) were higher than standard in some regions, so more arrangements should consider for increasing of drinking water quality in Tehran.
Zahra Salehi Reyhani; Zahra Khoshnood
Abstract
In order to investigate the biofilm creating bacteria in drinking water of Ahvaz, Iran, 4 different types of frequently used kitchen dishes (made up of plastic, glass, zinc, and teflon) were used for storage of drinking water under the same conditions at room temperature (25 °C) in triplicate order. ...
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In order to investigate the biofilm creating bacteria in drinking water of Ahvaz, Iran, 4 different types of frequently used kitchen dishes (made up of plastic, glass, zinc, and teflon) were used for storage of drinking water under the same conditions at room temperature (25 °C) in triplicate order. After the formation of the slime layer, microbiological tests were performed. Results showed that after 3 days, the biofilm layer was created. The biofilm creating bacteria of studied water belonged to both the gram-negative and gram-positive groups and were identified as follows: Staphylococcus aureus, Eschershia coli, Salmonella typhimorium, Entrobacter aerogenes, and Shigella sp. Results showed that the plastic dishes had the highest rate of bacterial growth and E. coli with 65 % of the growth was the most abundant bacteria of the investigated biofilm. It could be concluded that even in purified drinking water there were bacteria with the ability to create biofilm which needs more attention to purification processes and water storage in consideration with the quality of the dishes.
