Monitoring and assessment of water quality in Tehran city using physicochemical and microbial indexes

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 ۳۰ regions of Tehran city during ۲ months in summer of ۲۰۲۰ 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 (۶.۵۰ to ۷.۸۱), turbidity (۰.۰۱۱ to ۲.۹۸۳ NUT), chloride level (۲۴۰.۴۲ to ۳۲۱.۳۴ mg/L) and nitrate value (۷.۲۱ to ۲۰.۰۴ mg/L) were in allowable ranges. The phenolphthalein alkalinity was not found and methyl orange alkalinity was detected in the range of ۳۱.۵۴ to ۱۴۷.۲۲ (mg/L) in samples. The electrical conductivity (۱۴۰۱.۷ to ۱۹۷۲.۱ 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 (۰.۸۵ to ۱۵.۹۰ μg/L), cooper (۰.۰۴ to ۳.۳۸ mg/L), zinc (۰.۱۶ to ۳.۸۰ mg/L), lead (۰.۰۰۱ to ۰.۰۳۱ 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.

کلیدواژه ها:

Drinking water ، Tehran City ، Physicochemical ، Coliform ، Heavy metals