Content of cariostatic trace elements (F, Cu, and Zn) in the commercially packaged and public tap waters of Qatar

Objectives

Drinking water containing optimal levels of cariostatic trace elements is an effective preventive approach against community-wide dental caries. This study aimed to (i) determine the concentrations of fluoride, copper, and zinc in commercially packaged and public tap water available in Qatar, (ii) assess the accuracy of the content of these cariostatic trace elements on commercial water brand labels, and (iii) check for seasonal fluctuations in the levels of these trace elements in commercial and public water samples.

Methods

Duplicate samples from 20 commercial and six public tap water sources were collected once in the summer and winter seasons. Water samples were evaluated for fluoride concentration using ion chromatography (IC), whereas copper and zinc concentrations were estimated using inductively coupled plasma mass spectrometry (ICP-MS).

Results

The fluoride content of all commercial and public water samples was below the 0.25 mg/L detection limit of the IC instrument. Commercial water brands had copper and zinc levels below the ICP-MS detection limits (1.22 μg/L for copper and 0.24 μg/L for zinc). Copper levels in the public water samples ranged from <1.22 μg/L to 11 μg/L. Zinc levels in the public water samples ranged from 5 μg/L to 40 μg/L. Thirteen commercial water brands labelled their fluoride content, with most showing labelled fluoride levels <0.1 mg/L, consistent with the results of this study. The difference in trace element content between the summer and winter water samples was not statistically significant (P > 0.05).

Conclusions

Lower optimal cariostatic trace element content in the drinking water in Qatar could be a reason for the exceptionally high prevalence of dental caries. The results of this study could lead to public health advocacy for supplementing drinking water in Qatar with cariostatic trace elements that could potentially lower the prevalence of dental caries.