Bottled waters have been becoming increasingly popular in Korea over the last two decades due to the high demand for safe drinking water. Hydrochemical characterization of groundwater is essential for understanding quality properties of bottled waters. We investigated hydrochemistry of 60 manufacture factories for bottled waters in relation to geology. The mean EC value is highest in groundwaters of Ogcheon metamorphic rocks (213.6 μS/cm) > Precambrian gneiss (177.8 μS/cm) > Cretaceous granite (160.4 μS/cm) > Jurassic granite (131.3 μS/cm) > Quaternary Jeju Island volcanic rocks (99.2 μS/cm). The groundwater types are commonly classified as Ca-HCO₃, Ca-Na-HCO₃, or Ca-Mg-HCO₃ types depending on bed rocks. Based on correlation matrix, the groundwater chemistry was controlled by water–rock interactions. We established relationships between groundwater compositions and bedrock geology in Korea.

Radon concentrations in the raw water and treated water used for 59 brands of bottled water produced in South Korea were analysed. The radon levels in 59 raw water samples ranged from 3.7 to 476.8 Bq/L, with a geometric mean of 49.0 Bq/L. The mean radon levels in raw water samples were high in Jurassic granite aquifers and low in volcanic rock aquifers. However, the maximum radon levels were observed in metamorphic rock aquifers. The concentrations in 55 treated water samples ranged from 0.1 to 239.4 Bq/L, with a geometric mean of 7.7 Bq/L. In treated water, radon levels decreased by 16.0–98.9% (average, 74.9%) due mainly to storage in water tanks and treatment with granular activated carbon (GAC) filters. The radon levels in raw water and treated water samples exceeded the US EPA alternative maximum contaminant level (AMCL) of 148 Bq/L by 16.9% and 1.8%, respectively. Considering the radon reduction rate, it is anticipated that the radon concentrations in bottled water in stores will not exceed 148 Bq/L because it takes about 1–2 weeks for treated water to reach the customer as bottled water.

The Magumsan thermal waters of the southeastern Korean Peninsula are pumped out of six deep wells (average depth, 300 m) at temperatures of 30.8–49 °C. The thermal waters are chemically classified into two groups: NaHCO₃ type (40 °C), both of which have chemical compositions that are distinct from local groundwater (Ca–HCO₃ type). δ¹⁸O and δD values suggest that the thermal waters originate from meteoric water and they are isotopically fractionated by silicate hydration or H₂S exchange. δ³⁴S values (+7.0 to +15%) of dissolved sulfate in the thermal waters reflect enrichment in ³⁴S through kinetically controlled oxidation of magmatic pyrite in the thermal aquifer and mixing with paleo-seawater. On the ³He/⁴He vs. ⁴He/²⁰Ne diagram, the thermal waters plot along a single air mixing line of dominant crustal He, which indicates that the heat source for the thermal waters is non-volcanogenic thermal energy that is generated from the decay of radioactive elements in crustal rocks. Chalcedony geothermometry and thermodynamic equilibrium calculations using the PHREEQC program indicate a reservoir temperature for the immature thermal waters of 54–86 °C and 55–83 °C, respectively.

The purpose of this study is to delineate the main contributions controlling the chemical composition of groundwater and spring water samples at Jeju Island, South Korea. Groundwater and spring water can be grouped as three chemical types: Fresh water (Ca, Na-HCO₃), sea water mixing (Na-Cl, SO₄) and contamination (Ca-NO₃, Cl). By factor analysis, three factors can explain about 87% of chemical variances: Factor 1 (Na⁺ and Cl⁻), factor 2 (NO₃⁻), and factors 3 (HCO₃⁻), which are regarded as indicative ions of sea water mixing, contamination and mineral-water interaction, respectively. Sea water intrusion in the southeastern area of Jeju Island is due to downward distribution of Seogwipo Formation, which plays a role as an aquiclude preventing sea water intrusion in other areas, under sea level at the southeastern coastal area. Nitrate contamination is likely to be affected by pollution sources, i.e., agricultural activities, horse farms and municipal sewage. Thermodynamic saturation index indicates that most of waters are undersaturated with respect to major minerals, which may result from insufficient reaction time within a permeable aquifer. The unsaturation state corresponds to low load scores of Ca, Mg, Na, K, and SiO₂ in factor 3, which means a low contribution of mineral-water interaction.

In this study, the state of the production, market, and integrated management of mineral water in South Korea was assessed and a strategy was established to improve the competitiveness of mineral water with respect to foreign brands. Diverse data, including a number of mineral water manufacturers, daily permitted volume, daily production amounts, sales volume, and sales amounts, were used to clarify the state of mineral water and establish a strategy. Real-time data transmitted from the mineral water manufacturers were analyzed and managed in an integrated management system (IMS). Chemical characteristics of mineral water were analyzed to assess water quality and identify problems related to contamination. This study shows that specialization plans according to geological characteristics should be established, rather than focusing on quantitative growth by a low-cost sales method. The establishment of contamination management plans was found to be needed for wells with potential pollution due to sub-surface inflow into the wells. We suggest that an independent editing system of the attribute information needs to be designed based on the analysis and management of the IMS.