Assessment of Medical Geology from Major Element Trilinear Diagrams Cl-SO4-HCO3 and Na-K-Mg from Geothermal and Non-Geothermal Springs; Case Study the Wayang Windu Geothermal Area, West Java, Indonesia

Medical geology research involves the processes, deficiencies, and excessive exposure of significant elements and minerals to present solutions to health problems. Minerals from volcanic aquifers from geothermal and non-geothermal springs interest medical geology research. Major elements in source rocks essential for our health come from the rocks beneath the earth’s surface. This study aims to evaluate the medical geology of major elements in the water from volcanic aquifers in the Wayang Windu Geothermal Area. The methods used are trilinear analysis of major elements, Piper diagram, and statistical analysis. We have investigated six cold springs, four hot springs, and three dug wells surrounding the Wayang Windu geothermal area. The results of hydrochemical study and field checking identified the location of water sources that have potential uses in medical geology and balneotherapy. The primary relationship elements in the Piper Diagram defined five major water types: CaCl, MgCl, CaMgHCO3, and CaHCO3. Results from hydrochemical analyses, statistics, and trilinear diagrams were used to identify springs suitable for medical geology and balneotherapy. Hot springs with good health criteria that meet the balneotherapy requirements are found at locations H1, H2, H3, and H4. Hydrochemical data shows that hot springs in several areas of Pangalengan are suitable for bathing and body contact activities but not for drinking water. Cold springs at locations C1, C2, C3, C4, C5, and C6 meet the drinking water criteria surrounding the Wayang Windu geothermal area.


Introduction
The acquisition of precise geochemical data is of utmost importance in evaluating the potential health implications arising from exposure to elevated concentrations of potentially hazardous substances, as well as in identifying areas where the scarcity of vital elements in groundwater and soil may have an impact on the well-being of both animals and humans [1].Elements in groundwater that are important for health can be classified into five types according to their sources and characteristics: geogenic substances, anthropogenic contaminants, biogenic elements, pathogens, and emerging contaminants [2] [3].The association between groundwater quality and human health can enhance groundwater's visibility as a critical resource.However, it is essential to acknowledge the existing knowledge gap about the interconnectedness of these factors, which necessitates the need for interdisciplinary research efforts to bridge this gap [4].Examining knowledge gaps and future developments pertaining to the correlation between groundwater quality and human health is paramount in contemporary discourse [5].The field of medical geology study focuses on investigating the effects of excessive or inadequate exposure to essential elements and minerals to propose interventions for health-related issues [6] [7].
Medical geology research studies mineralization from volcanic aquifers and geothermal/nongeothermal springs.According to [8], the rocks beneath the Earth's surface contain significant constituents crucial for maintaining our health.Throughout history, springs and hot springs have been utilized globally for various purposes, such as the consumption of potable water, therapeutic benefits, and expediting the healing process [9].Tectonically produced natural mineral water exhibits hydrogeochemistry influenced by the lithology and mineral structure arrangement.This water contains various elements, including magnesium, potassium, calcium, iron, and other trace elements, positively affecting human health [10] [11].The earliest documented utilization of geothermal resources can be traced back to ancient times, when hot water was employed for bathing and medical practices, often associated with traditional religious customs, as observed during the era of Hippocrates.The primary advantages of hot springs reside in their therapeutic and curative properties for medical intervention [12].Researchers from several countries have extensively investigated the correlation between utilizing natural factor therapy and developing healing bath concepts [13].
Cold and hot springs have historically played a significant role in traditional cultural practices related to bathing, healing, and spiritual purification in various Asian countries, including China, India, and Japan [14].Numerous scholarly investigations have been undertaken on the subject of groundwater therapy within the field of medical geology.These studies mainly focus on comparing the utilization of mineral-rich groundwater in natural therapeutic approaches.Notable examples include the research conducted by [15] [16] [1] [7] [17].Recently, there has been a notable surge in global interest in natural mineral waters.This heightened attention can be attributed to growing apprehensions surrounding the quality of surface water, the potential health benefits associated with mineral waters, and the evolving patterns of human lifestyles.According to a recent ecological review conducted by [9], springs play a crucial role in preserving ecosystems that harbor diverse flora and fauna.These ecosystems rely on groundwater flow to sustain their environmental conditions and riparian habitats.
According to [17], there is a prevailing belief among the Indonesian population regarding the health benefits of hot water, as it is believed to possess a rich mineral content conducive to overall well-being.However, it is worth noting that not all communities know that hot springs constitute an integral component of the geothermal system.Prior research has established a positive association between beneficial minerals and the possible health advantages of geothermal springs.Numerous medical conditions can be effectively managed by utilizing diverse thermal springs containing vital minerals known for their therapeutic properties, typically in hot springs [18].Wayang Windu is a geothermal region located in the province of West Java, Indonesia, characterized by its many hot and cold springs with significant potential.Geological conditions and geological structures greatly influence the hydrochemistry of springs' primary constituents, offering potential for medical and geological therapy.
This study aims to examine the primary components of hydrogeochemical behavior in natural mineral waters with varying lithological formations.The objective is to assess the field of medical geology using major element trilinear diagrams of Cl-SO4-HCO3 and Na-K-Mg obtained from both geothermal and non-geothermal springs.It is necessary to comprehend the hydrological and geochemical processes that restrict the availability of natural mineral water sources.The present study aims to categorize various types of water based on their hydrogeochemistry.Additionally, it seeks to determine the factors that govern the presence of minerals in water and assess the hydrogeological and geochemical processes involved.The research employs multivariate statistics and trilinear diagrams as analytical tools to achieve these objectives.In this study, we conducted an investigation to examine the concept that the 3 lithological setting exhibits a strong correlation with natural mineral waters, which display distinct physical and chemical characteristics in hydrogeochemical measurements obtained from various springs.

Existing Geothermal Dryhouse
The research area is geographically situated inside the Bandung Basin region (see Figure 1).The Bandung Basin can be described as a volcanic arc that occupies a valley situated between two mountain ranges, with its underlying structure being connected to the Bogor Basin [19].The research area is situated inside the Bandung Zone, which is physiographically positioned in the central region of Java Island [20].The Bogor Zone demarcates the northern boundary of the zone and is juxtaposed with the southern mountain zone to the south.The Bandung Zone exhibits a higher level of economic depression compared to the neighbouring zones, namely Bogor and the Southern Mountains Zone.The demarcation line separating the Bandung Zone and the South Mountains is delineated by a sequence of volcanic formations, namely Kendeng, Patuha, Tilu, Malabar, Papandayan, and Cikuray.A portion of the Bandung Zone is characterized by the presence of volcanic and alluvial sediments, whereas the highlands are predominantly composed of tertiary rock formations.The Quaternary volcanic chain encompasses the geological region that spans the boundary between the elevated banks of the central portion of the Southern Mountains and the Bandung Zone.
According to the regional geological maps of the Garut and Pameungpeuk sheets [21], the rock units present in the research area are as follows: The Late Pleistocene (Qmt) Malabar-Tilu volcanic rock groups are characterized by their composition, which primarily consists of tuff and lava breccias.These rock units also contain minor quantities of pumice and lava.The breccias found in the local area are 4 relatively compact and cohesive.The geological formation under consideration is a volcanic deposit from the late Pleistocene epoch.It is characterized by the presence of tuff rock, which has a fine-coarse texture and is composed of dacitic material.Additionally, the deposit contains a tuffaceous breccia consisting of pumice fragments and ancient lava deposits that display an andesitic-basalt composition.The Waringin-Bedil Andesite Unit, located in the Old Malabar region, is classified as an Early Pleistocene formation.This unit is characterized by a diverse rock composition, which includes intercalated lava, breccia, and tuff.The rocks within this unit primarily consist of andesite, containing minerals such as pyroxene, hornblende, and pumice.The study was carried out in the Wayang Windu Pangelengan region, situated in the volcanic area of South Bandung, West Java, Indonesia.This location is physically positioned between longitudes 107030'E -107040'E and latitudes 7000'S -7010' S (Figure 2).

Methodology
The assessment of groundwater quality within the hydrogeologic system is conducted by analyzing water samples collected from 13 specific spots.These sampling locations represent the diverse groundwater and geological characteristics of the system.A comprehensive examination was conducted on six cold springs, four hot springs, and three excavated wells in the vicinity of the Wayang Windu geothermal area.This study utilized eleven laboratory variables to assess the groundwater quality for medical geology investigations.These variables encompassed physical characteristics such as pH, temperature, total dissolved solids (TDS), and electrical conductivity (EC), as well as chemical components including sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), chloride (Cl-), sulfate (SO42-), and bicarbonate (HCO3-) concentrations at each water sample site.These analyses can provide valuable insights in further elucidating the appropriate therapeutic approach.The equipment employed for collecting, storing, and analyzing chemical components underwent cleaning procedures with distilled water.The samples were gathered using a grab sampler throughout the spring season.During the sampling process, additional water quality indicators, namely pH, temperature, electric conductivity, and total suspended particles were assessed at the designated collection sites.The pH was determined by employing a portable pH meter that was calibrated before to each measurement.The instrument underwent calibration before its deployment in the field.The chemical test of water samples was conducted at the E-service scientific laboratory, affiliated with the National Research and Innovation Agency, BRIN.The trustworthiness of the chemical composition was assessed through the application of charge balance procedures, as outlined by [22].The parameters encompass crucial cations, namely sodium (Na + ), potassium (K + ), calcium (Ca 2+ ), and magnesium (Mg 2+ ), as well as anions such as sulfate (SO4 2-), chloride (Cl -), and bicarbonate (HCO3 -).The concentrations of sodium (Na + ), potassium (K + ), calcium (Ca 2+ ), and magnesium (Mg2+) were determined through the utilization of Atomic Absorption spectrometry (AAS).The estimation of bicarbonate (HCO3 -) was conducted by a titration method using H2SO4, as described by [23].The chloride ions (Cl -) concentration was assessed by titration using standard AgNO 3 solution.On the other hand, the concentration of sulfate ions was studied using a spectrophotometer.
The employed techniques encompass a trilinear analysis of primary constituents, a Piper diagram, and a bivariate study of main elements.The chloride (Cl -), sulfate (SO4 2-), and bicarbonate (HCO3 -) anions present in groundwater samples were graphed on a ternary diagram to ascertain the water classification of hot springs and hydrothermal fluids, using hydro chemical concentrations as a basis.The Cl --SO4 2--HCO3 -triangle plotting diagram allows for the identification of four distinct categories of geothermal fluid types: volcanic water, steam water hot, peripheral, and cooked water.The classification of the geothermal fluid type is ascertained by quantifying the proportional distribution of the primary anions present in the geothermal fluid, expressed as percentages.Subsequently, these values are graphically represented on the Cl --SO4 2--HCO3 -triangle diagram, as proposed by [24].The Pearson correlation coefficient is utilized to assess the association between the concentrations of the physicochemical parameters.The data analysis was conducted utilizing the SPSS Statistics 26 software.The Pearson correlation coefficient results exhibited statistical significance and demonstrated a substantial link among water parameters [25].Cluster analysis is a valuable component of multivariate statistical methods, as it facilitates the examination of geochemical patterns and the subsequent interpretation of their hydrochemical features [26].

Physico-chemical Parameters
The present investigation methodically obtained 13 groundwater samples from various locations surrounding the geothermal area.Figure 3   Table 1 summarizes the concentrations of main ions in the springs of the Wayang Windu area, compared to the standards set by the World Health Organization [27].The presence of many critical constituents in drinking water is a matter of concern from a public health perspective due to the possibility of exceeding suggested thresholds.Nevertheless, specific crucial components are essential for maintaining good health and must be present in drinking water in precise amounts.
The concentrations of major ions compared to WHO Standard [27] in the springs of the Wayang Windu area are summarized in Table 1.Most major elements in drinking water are apprehension from a community health point of view because of the potential for excess above recommended limits.However, some major elements are essential to health and must be present at specific concentrations in drinking water.Total dissolved solids (TDS) and conductivity are derived from environmental factors, including geological conditions and the impact of human activities such as using fertilizers, household practices, and agricultural operations [28].In the local context, the elevated Total Dissolved Solids (TDS) levels during the dry season can be attributed to the evaporation process and the lack of a diluting mechanism.The decrease in mineral content observed in groundwater during the rainy season might be attributed to the dilution caused by the influx of rainwater, as discussed by [29].The extent of rock-water reactions is influenced by the hydrogeological features of rocks [30].
Sodium (Na + ) is frequently observed inside igneous rocks in volcanic regions [31].Its presence can be attributed to the process of silicate weathering, which results in the formation of residual materials within clay minerals [32].The concentration of sodium ions (Na + ) in Wayang Windu varied between 4.84 mg/l and 79.64 mg/l, whereas the concentration of potassium ions (K + ) ranged from 1.23 mg/l to 22.08 mg/l, as shown in Table 1.According to [33], excessive consumption of sodium (Na + ) has a detrimental impact on individuals with hypertension and pregnant women with toxemia.The body's ability to retain water depends on a significant quantity of sodium (Na + ) and potassium (K + ) ions.The main goal of heart failure treatment is to reduce the concentration of Na + in the blood and promote water excretion from the body [34].
The regulation of various physiological processes in the human body, such as blood vessel contraction, blood coagulation, nerve transmission, and muscle contraction, is attributed to calcium ions (Ca 2+ ) [33].The calcium ion (Ca 2+ ) concentrations varied between 5.97 mg/l and 68.51 mg/l, as indicated in Table 1.In natural environments, magnesium ions (Mg 2+ ) can be attributed to volcanic rocks characterized by basaltic to andesitic compositions [35].The magnesium ion (Mg 2+ ) concentrations span a range of 3.61 mg/l to 83.96 mg/l, as seen in Table 1.According to [36], the presence of insufficient levels of magnesium in the body can lead to several health hazards, including atherosclerotic vascular disease, eclampsia in pregnant women, vasoconstriction, acute myocardial infarction, infection, and hypertension.The elevated levels of HCO3 -in groundwater in various locations can be attributed to the ample availability of CO2 resulting from gas dissolution and the infiltration of precipitation seepage [35] [37].The range of HCO3 -levels observed in this study varied from 10.54 mg/l to 760.36 mg/l.
The elevated concentration of chloride ions (Cl -) in the central facies is subject to influence from anthropogenic and hydrothermal activities, as discussed by [38].The chloride (Cl -) concentrations varied between 0.5 mg/l and 41.32 mg/l.Sulfate ions (SO 4 2-) are derived from various sources, including mineral weathering, volcanic activity, leaching of fertilizers from agricultural soils, and industrial wastewater runoff [39].The concentrations of SO4 2-ions varied between 1.28 mg/l and 154.82 mg/l.Elevated levels of sulfate in water indicate water pollution, and the presence of high sulfate concentrations in water has been associated with the potential to induce gastrointestinal irritation [33].

Statistical Analysis
Pearson analysis was carried out to determine the relationship among the concentrations of physicochemical parameters [25].Pearson analysis shows the correlation among hydrogeochemical parameters (Table 2).Temperature strongly correlates with EC, Na + , K + , Mg 2+ , Ca 2+ SO4 2-, and HCO3 -.EC strongly correlates with Na + , K + , Mg 2+ , Ca 2+ SO4 2-, and HCO3 -.EC also strongly correlates with temperature, Na + , K + , Mg 2+ , Ca 2+ SO4 2-, and HCO3 -.It is also obvious that Na + strongly correlates with temperature, EC, K + , Mg 2+ , Ca 2+ SO4 2-, and HCO3 -.K + strongly correlates with temp, EC, Na + , Mg 2+ , Ca 2+ SO4 2-, and HCO3 -.Ca 2+ strongly correlates with temperature, EC, Na + , K + , Mg 2+ , SO4 2-, and HCO3 - .Mg 2+ strongly correlates with temperature, EC, Na + , K + , Ca 2+ , and HCO3 -.SO4 2-has strong correlation with temperature, EC, and Na + .HCO3 -strongly correlates with temp, EC, Na + , K + , Ca 2+ , and Mg 2+ .Physical parameters such as temperature and EC closely correlate to anions and cations.Cluster analysis effectively explores and interprets hydrochemical characteristics [26].This method uses hierarchical clusters to measure the distance between variable clusters [40].In this study, hydrochemical data with similar properties were clustered in a group, including Na + , K + , Ca 2+ , Mg 2+ , Cl - , SO4 2-, and HCO3 -, which was considered to evaluate the characteristics of groundwater using the average linkage hierarchy method (Figure 4).Based on the dendrogram of the cluster analysis results, there are two groups with hot and cold spring characteristics: Group A, with the hydrochemical parts of the cold springs, can be used for drinking water for the community, and Group B, with the hydrochemical features of the hot springs, can be used for medical geology therapy.The chloride water found in the springs within the research area results from combining hydrothermal fluids with connate water or formation water.The phenomenon of condensation in this region gives rise to the formation of acid sulfate water.The ensuing condensate water may undergo mixing with meteoric water or groundwater, leading to the formation of sulfate-bicarbonate water.The CaMgHCO 3 facies type is located within the cold springs C1, C2, C3, C4, C5, and C6, found in Old Volcanic Rock formations.The CaHCO3 facies type is located within the cold springs H1, H2, and H3, Old Volcanic rock formations.Bicarbonate water is attributed to combining hydrothermal fluids with meteoric water or groundwater.The springs in the research area are similar to hot springs utilized for balneotherapy in many nations.For instance, CaHCO3 water is employed in Latvia to treat gastrointestinal ailments, such as hepatic insufficiency.The condition known as gout has been studied by [41].Bicarbonate (HCO3 − ), IOP Publishing doi:10.1088/1755-1315/1293/1/01200210 the primary anion, exhibits anti-acid properties, enhances pancreatic function, acts as a hepatoprotector, and promotes the excretion of uric acid in urine.
Additionally, mineral water containing high levels of carbon dioxide (CO2) exceeding 250 mg/L has been found to aid digestion, as [42] noted.Korean spas utilize a specific variety of sulfide-sodium chloride water to treat dermatitis as a sedative and address psoriasis, as documented by [43].According to [15], sulfur-based water is utilized in American spas to treat burns, respiratory ailments, skin conditions, and rheumatic disorders.

The type of water based on Geothermal Fluid
The relative content of subsurface fluid elements can be used to determine the fluid's chemical type, flow type, and source.The maturity of geothermal manifestations can be selected from the elemental content of Na + , K + , and Mg 2+ by plotting the Na-K-Mg [44]-ternary diagram.Mg 2+ is an element that has a small concentration at high temperatures (0.01-0.1 ppm).The high concentration of Mg 2+ is sourced from dilution by surface water with a high Mg 2+ content [45].The fluid release process observed at the research site exhibits the presence of immature Na + , K + , and Mg 2+ ions in the water, suggesting a combination of hydrothermal fluid and meteoric water (Figure 6a).The potential origin of sulfate, with concentrations reaching up to 154.82 mg/L, is likely attributed to the formation of water inside the sedimentary rock stratum.Before transitioning into a surface condition, the fluid experiences a dilution process by incorporating meteoric water or groundwater.Cl --HCO3 --SO4 2-for classifying geothermal water.
The relative contents of Cl-, SO 4 2-, and HCO 3 -from groundwater samples are plotted on a ternary diagram to determine the type of water based on the hydrochemical content.The results of plotting the percentages of the three elements Cl-, SO4 2-, and HCO3-for water sources include mature, peripheral, and steam-heated water (Figure 6b).The fluids in locations C1, C2, C3, C4, C5, and C6 have a peripheral water type.While the fluid contained in hot springs H1, H2, H3, and H4 near Mt Wayang and Mt Windu are generally of the type of steam hot water, this indicates that the water is formed on the lower slopes of the geothermal system.

Direct utilization for medical geology treatment and balneotherapy
Through field investigations, primary hydrochemical analysis, and secondary data analysis, it becomes feasible to ascertain the precise whereabouts of water sources that hold potential for application in medical geology and balneotherapy.According to [46], for springs to be suitable for balneological purposes, they must possess minerals that are appropriate for balneotherapy, have the potential for sustainable discharge, and demonstrate a high degree of mineralization while simultaneously having a low presence of undesirable contaminants.It is imperative to consider the diversity of significant aspects and the continuity of the flow rate [15].
The hydrochemical composition of hot and cold springs exhibits variations, influencing their utilization.The hot springs that meet the standards for good health and balneotherapy requirements are at designated areas H1, H2, H3, and H4.Based on the available data, it can be observed that the hot springs located in various regions of Pangalengan exhibit suitability for engaging in bathing and body contact activities.However, it is essential to note that these hot springs are unacceptable for drinking water.The cold springs in C1, C2, C3, C4, C5, and C6 satisfy the established criteria for drinking water.The mineral composition of cold springs in volcanic regions renders them appropriate for utilization as a viable supply of pristine water.Direct utilization is contingent upon several balneological features specific to each potential site, as each site necessitates distinct criteria for balneotherapeutic investment.

Conclusion
Hydrochemical analysis and field verification enable the identification of water sources that exhibit promising potential for applications in medical geology and balneotherapy.The hot and cold springs' hydrochemical composition shows variations, rendering them suitable for diverse applications.Hot springs that possess favorable health characteristics following the standards of balneotherapy can be identified at designated sites H1, H2, H3, and H4.The hydrochemical analysis reveals that the hot springs in various regions of Pangalengan exhibit favourable characteristics for bathing and bodily contact activities.However, it is essential to note that these hot springs are deemed unsuitable to consume as drinking water.Cold springs located in C1, C2, C3, C4, C5, and C6 have characteristics that align with the requirements for potable water.Further investigation is necessary to mitigate the adverse effects of hazardous toxic components through the implementation of direct utilization strategies, which a comprehensive analysis should inform of various hydrochemical characteristics.This discovery is relevant and warrants further exploration, serving as a crucial link between science and society.

Figure 2 .
Figure 2. The present document showcases a geological map of Pangalengan, a region located in West Java, Indonesia.Modification from [21].
depicts the sample ID and concentration of physicochemical parameters for all the groundwater samples.A Schoeller diagram to investigate patterns in the concentration of anions and cations and to analyze the chemical composition of rock materials.The different ways of three water groups (hot springs-H, cold springs-C, and dug wells-D).

Figure 3 .
Figure 3.The different patterns of three water groups (hot springs-H, cold springs-C, and dug wells-D) are shown in a Schoeller diagram.

Figure 4 .
Figure 4.The dendrogram of the cluster analysis in the research area

Figure 5 .
Figure 5.The Piper Diagram describes the water type in the Wayang Windu geothermal area.

Table 1 .
Physico-chemical parameters from Wayang Windu samples compared to WHO Standard

Table 2 .
Pearson correlation matrix for the hydrochemical concentration.