A City‐wide Investigation of the Isotopic Distribution and Source of Tap Waters for Forensic Human Geolocation Ground‐truthing

Human geolocation is prefaced on the accuracy of the geographic precision of mapped isotopic values for drinking water. As most people live in cities, it becomes important to understand city water supplies and how the isotopic values uniquely reflect that city. This study investigated the isotopic distribution of δ²H and δ¹⁸O from sourced tap waters that were collected from across the Metro Vancouver (MV) area (n = 135). The results revealed that the isotopic values reflect their water sources with a range of 5.3‰ for δ¹⁸O_tap and 29.3‰ for δ²H_tap for MV. The results indicate that individual cities need higher resolution studies to determine their tap water isotopic ranges, and a good understanding of the water supply network itself for human geolocation work. With an extended high‐resolution understanding of each city, human tissue may be compared with more certainty for geolocation.