Assessing the authenticity of commercial deep-sea drinking water by chemical and isotopic approaches

Abstract

This study combines stable isotopes and chemical elements with statistical principal component analysis (PCA) to assess the authenticity of bottled commercial drinking water desalinized from deep seawater in the Taiwan market. Isotopic results indicate that true bottled deep-sea drinking water (DSDW) exhibits about 0 ‰ for both δ²H and δ¹⁸O values, which are values similar to those of open seawater. By comparison, suspected counterfeit DSDW products display δ²H and δ¹⁸O values of around −51 ‰ and −8 ‰, respectively. These values are representative of terrestrial freshwater. In addition, suspected counterfeit DSDWs have δ and electrical conductivity values similar to a mixed water (MW) product that was manufactured by purifying terrestrial freshwater and adulterating this with small amounts of brine. Furthermore, PCA results indicate the chemical constitution of suspected DSDW products to be similar to the MW product which falls between purified terrestrial freshwater and desalinized open seawater. These similarities imply that suspected counterfeit DSDW products are manufactured in a similar manner to the declared MW product. This study demonstrates how combining knowledge of stable water isotopes and PCA can be used in assessing the authenticity of commercial DSDW products. The method should be of great interest to similar investigations elsewhere.

Keywords:

• authenticity
• deep-sea drinking water
• hydrogen-2
• oxygen-18
• principal component analysis
• stable isotope tracer technique

The authors are very grateful to two anonymous reviewers for their constructive comments in greatly improving our manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by National Chung Hsing University and Agricultural Research Institute, Council of Agriculture, Executive of Yuan, Taiwan, Republic of China [grant number NCHU-TARI 10201].