Source identification and geochemical characteristics of surface and groundwater from Larji-Rampur window, Himachal Himalaya: Implications for socio-environmental perspectives

Understanding water quality and its interaction with the litho-units is essential for human activity and socio-environmental development. This study focused on surface, groundwater, and thermal springs water in the Larji-Rampur Window (LRW), Himachal Himalaya, with results revealing that the water was alkaline with an average pH of 7.91. The TDS ranged from 16.38 to 367.92 mg/L, while electrical conductivity (EC) varied between 26 and 584 µS/cm. Calcium (Ca^2 +) dominated the major cations (208–2424 µE), followed by magnesium (Mg²⁺), sodium (Na⁺), and potassium (K⁺), with bicarbonate (HCO₃⁻) being the main anion (200–3000 µE). Mixing diagrams, Gibbs plot, and ionic ratios indicated carbonate weathering as the primary factor, with contributions from silicate weathering. The first factor of principal component analysis (PCA) explains 66.44 % of the variance, indicating carbonates as the primary source of dissolved loads in the basin, with contribution from silicate weathering. The isotopic analysis (δ¹⁸O and δD) showed the samples’ alignment along the Global Meteoric Water Line (GMWL), with a slight compositional shift due to water-rock interactions. The δ¹³C values (-13.7 to −3.6 ‰), suggested their derivation from associated carbonate rocks. Lithium (Li), strontium (Sr), and iron (Fe) were identified at higher-than-permissible limits in groundwater and thermal springs of Garsah and Parvati Valley. Arsenic levels in geothermal springs reached 48.79 ppb, exceeding WHO guidelines. This study underscores the presence of hazardous elements threatening human health and emphasizes the importance of geological influences on water quality. This work further advocates the need for regular monitoring and management strategies to mitigate risks associated with trace element contamination.