Isotopic composition of dissolved inorganic carbon in bottled waters on the Slovene market

Abstract

This study investigates the stable isotopic composition of dissolved inorganic carbon (DIC), expressed as δ 13C DIC, in domestic and foreign bottled waters randomly collected on the Slovene market. All together 58 brands and 16 replicates were analysed. The δ 13C DIC values varied between −63.1‰ and +1.0‰ with an average of −12.3‰. Average δ 13C DIC values for naturally sparkling, artificially sparkling, still and flavoured waters were −3.3‰, −36.5‰, −10.0‰ and −11.0‰, respectively. The lowest values are characteristic of artificial sparkling waters (minimum −63.1‰) and can be attributed to injection of industrial CO 2 during bottled water production. Therefore, determination of the isotopic composition of DIC can represent a useful analytical tool to distinguish between natural and artificially sparkling waters. Furthermore, the method used enabled determination of the various origins of still waters. From the bottled waters sampled it was possible to discern waters that originate from deeper aquifers, from aquifers in equilibrium with soil CO 2, or from aquifers with their recharge in a mountainous area. Finally, δ 13C DIC values of flavoured waters illustrate that isotopic fractionation occurs during the production process and that δ 13C DIC values in products of some producers have a large variation.