Comparison of the Mineral Content of Tap Water and Bottled Waters

Abstract

OBJECTIVES: Because of growing concern that constituents of drinking water may have adverse health effects, consumption of tap water in North America has decreased and consumption of bottled water has increased. Our objectives were to 1) determine whether North American tap water contains clinically important levels of calcium (Ca 2+ ), magnesium (Mg 2+ ), and sodium (Na + ) and 2) determine whether differences in mineral content of tap water and commercially available bottled waters are clinically important. DESIGN:We obtained mineral analysis reports from municipal water authorities of 21 major North American cities. Mineral content of tap water was compared with published data regarding commercially available bottled waters and with dietary reference intakes (DRIs). MEASUREMENTS AND MAIN RESULTS:Mineral levels varied among tap water sources in North America and among bottled waters. European bottled waters generally contained higher mineral levels than North American tap water sources and North American bottled waters. For half of the tap water sources we examined, adults may fulfill between 8% and 16% of their Ca 2+ DRI and between 6% and 31% of their Mg 2+ DRI by drinking 2 liters per day. One liter of most moderate mineralization European bottled waters contained between 20% and 58% of the Ca 2+ DRI and between 16% and 41% of the Mg 2+ DRI in adults. High mineralization bottled waters often contained up to half of the maximum recommended daily intake of Na + .CONCLUSION: Drinking water sources available to North Americans may contain high levels of Ca 2+ , Mg 2+ , and Na + and may provide clinically important portions of the recommended dietary intake of these minerals. Physicians should encourage patients to check the mineral content of their drinking water, whether tap or bottled, and choose water most appropriate for their needs.

Comparison of the Mineral Element Content of Public Drinking Fountains and Bottled Water: A Case Study of Ferrara City

“…Using ΣCation, the content of mineral elements in the bottled water followed this order: Group 3 > Group 2 > Group 1 ( Table 1). According to Azoulay et al [6], a comparison between DRI and mineral intake from drinking water is made using a reference volume of 2 litres. The DRI of Ca 2+ is 1200 mg/day; for Mg 2+ , 420 mg/day; 500 mg/day for Na + ; and 4700 mg/day for K + .…”

“…The main source of mineral intake is water, but significant differences exist among the mineral content of available drinking water, and often water ingested daily does not contain the recommended dietary allowances [6].…”

“…The use of water for body rehydration is also recommended given that the ions in water are easily absorbed from the gastrointestinal tract [9], and the best way to reintegrate minerals is to drink water with an adequate total dissolved salt content [6].…”

“…Mineral levels of public drinking water (for example, PDRF) vary among various cities, and commercially available bottled water has different compositions related to the hydrology and chemical characteristics of the water sources [6]. Therefore, people should be selective when deciding which water to drink when jogging.…”

“…Regarding the environmental impact, it is known that Polyethylene Terephthalate (PET) water bottles (production, transportation, disposal, packaging waste and pollution) and mineral water industry (bottling, trading and transporting) impacts are extremely negative [11,[17][18][19][20]. In terms of health, mineral elements in bottled water are in some cases low, whereas often, public drinking water sources have an optimal mineral profile (high levels of Ca 2+ and Mg 2+ and little Na + ), and adequate daily consumption of tap water may help people supplement their dietary intake of mineral nutrients [6].…”