M.A. Thesis:

Evaluation of nitrate٫nitrite and microbial contamination bottled water in sabzevar.

An investigation on the amount of nitrate, nitrite and microbial contamination of bottled water in the city of Sabzevar Abstract Objective: Due to the dangerous effects of consuming water contaminated with heavy metals, nitrates, nitrites and harmful bacteria in the human body, together with the increasing preference of using bottled drinking water in modern societies, investigating on the amount of chemical and microbial contamination of bottled drinking water seems extremely important. Therefore, that was put under examination in the city of Sabzevar and during different seasons. Materials and methods: Ten samples of drinking and mineral water were collected in the city of Sabzevar during the four seasons. Nitrite and nitrate were measured by photometry. Microbial tests were performed using culture method. Findings and results: The highest amount of nitrite in drinking water was obtained in summer (0.0288 mg/lit) which was more than the permissible limit (0.02 mg/lit), but the effects of the seasons were not significant. Although nitrate was the highest in the spring (8.530 mg/lit) which was less than the permissible limit (50 mg/lit), but the effects of the other seasons were meaningful (p<0.05). In remaining mineral water, nitrite and nitrate were less than the standard permissible limit and the effects of the seasons were not meaningful, too. For existence of Coliform and E.Coli, through the first sampling during summer, three of them were positive for Coliform, but in other samples and seasons, no contamination was observed. Keywords: bottled drinking water, mineral water, heavy metals, nitrite, nitrate, microbial contamination

Keywords: Keywords: bottled drinking water, mineral water, nitrite, nitrate, microbial contamina