First investigation of the physicochemical and bacteriological quality of the "Hajra Safra" thermal spring, Taza region (Morocco)

Abstract

Hajra Safra Spring, located in the Eastern Rif of northern Morocco, has long been used locally despite the absence of published hydrochemical and bacteriological data. This study presents the first peer-reviewed physicochemical and bacteriological characterization of this hypersaline thermal spring. A single grab sample was collected directly from the spring outlet in June 2026 following standardized sampling procedures. Physicochemical and bacteriological analyses were performed in an ISO/IEC 17025-accredited laboratory using standardized analytical methods, and the hydrochemical facies was determined using the Piper diagram. The results revealed an exceptionally mineralized water characterized by an electrical conductivity of 491.9 mS/cm and a dissolved major-ion load exceeding 270 g/L. Major ions were dominated by Na$^{+}$ and Cl$^{-}$, defining a sodium--chloride (Na--Cl) hydrochemical facies consistent with prolonged interaction with Triassic evaporitic formations. Elevated ammonium concentrations associated with very low nitrate levels are compatible with reducing groundwater conditions. Culture-based bacteriological analyses detected no total coliforms, Escherichia coli, or intestinal enterococci above the analytical detection limits, while low heterotrophic plate counts and one Sulfite-reducing Clostridia spores per 100 mL were observed. Because the investigation was based on a single sampling event and culture-dependent methods, the results should be considered a preliminary characterization. Further seasonal monitoring, expanded physicochemical analyses, molecular microbiological investigations, and hydrogeological studies are required to better understand the functioning of this unique hypersaline groundwater system and to evaluate its potential environmental and biotechnological significance.