Determination of calcium in Mashhad City tap water by flame atomic absorption spectrometry

Calcium in drinking water is one of the sources of calcium that may contribute significantly to the daily calcium intake. in this study,the samples of tap water were randomly taken from five zones of mashhad city. calcium concentration was determined by flame atomic absorption spectrometry (faas) technique. the precision of the method was evaluated. the cv% of 6 replicate determinations at 5 μg/ml ca was 4.2 in one day and 4.5,among 6 consecutive days. the recovery of spiked samples (98.7%) also showed that the proposed method is reliable for the determination of amounts of calcium in water samples. the mean of calcium in tap water in the city of mashhad was 52.61±12.91 (sd) μg/ml. at present,the amount of calcium in mashhad tap waters is within the national standard. however,due to the climate and environmental changes,determination of calcium in tap water of mashhad in different seasons is recommended.