Microbiological Contamination Profiling of Geothermal Hot Spring Water at Gambiran Padusan Bath, Pacet District, Mojokerto Regency

Abstract

This study provides an initial microbiological load assessment of Gambiran Padusan Bath hot spring water (36–39°C) using Total Plate Count (TPC) analysis based on ISO 4833-1:2013 standards. Pour plate technique on nutrient agar with 0.9% NaCl, across dilutions 10⁻¹ to 10⁻⁶, yielded 4.84 × 10⁴ CFU/mL from valid plates (25-250 colonies; averages: 219, 168.3, 126.3 CFU). Triplicate plating ensured reproducibility (RSD <10%, CV <15%), with declining counts in higher dilutions (17.7 to 0 CFU) confirming methodological reliability. Endogenous geothermal heat provides intrinsic disinfection, selectively favoring beneficial aerobes over pathogens, aligning TPC below WHO (<10⁵ CFU/mL) and BPAK 2017 recreational limits. Padusan's controlled microbiota poses minimal dermal/opportunistic infection risk during 15-20 min hydrotherapy sessions, supporting musculoskeletal relaxation (20-30% tension reduction), anti-inflammatory mineral absorption, and stress relief via endorphin induction. Logarithmic dilutions and 37±1°C incubation (mimicking skin temperature) optimized mesophile profiling, distinguishing therapeutic safety from bioprospecting. Negative 10⁻⁶ growth rules out hyper-contamination/aerosol risks. This baseline enables temporal monitoring, geotourism capacity planning (max 50 bathers/hour), and sustainable development, bridging public health with enzymatic bioprospecting potentials.

Keywords - Hot Spring; Hydrotherapy Safety; Microbial Load; Plate Count; Water Quality