Aquifers and Groundwater: Challenges and Opportunities in Water Resource Management in Colombia

Abstract

Water is essential for life on Earth, playing fundamental roles in climate regulation, ecosystem maintenance, and domestic, agricultural, and industrial processes. A total of 70% of the planet is covered by water. However, only 2.5% is fresh water, and much of it is inaccessible. Groundwater is the main source of the planet’s available water resources. For that reason, groundwater is a critically important resource, and is increasingly vulnerable due to the climate crisis and contamination. These challenges threaten the availability of clean and safe water, necessitating an understanding of effective and sustainable management. This review presents an overview of the concepts of aquifers and groundwater. Also, it reflects on the importance of these resources in developing countries such as Colombia (South America). In addition, it considers the characteristics of mineral waters, their uses, and associated risks, as well as their exploration and control policies. Colombia is a country with immense water and biological wealth and is crucial to maintaining the climate and availability of global water resources. Nevertheless, managing Colombia’s aquifers is a challenge, as many have not yet been fully explored. In order to achieve this, it is necessary to study hydrogeochemistry through the application of advanced technologies to analyze the dynamics, distribution, and quality of groundwater, as well as its vulnerability to pollution and climate change. On the other hand, the consumption of mineral groundwater can have health benefits, such as positive cardiovascular and gastrointestinal effects. But geogenic, biogenic, or anthropogenic elements such as heavy metals and microplastics can pose a risk to human health. The need for proper management of water resources to prevent risks to human health and the environment is emphasized. Therefore, an integrated approach to water resource management will ensure conservation and sustainable use, secure a continuous supply of freshwater, and facilitate adaptation to climate change.

1. Introduction

Biological systems are completely dependent on water due to its physicochemical characteristics that favor essential biochemical processes and allowed the evolution of life [1]. Cells and living organisms in general are mostly composed of water, and in the case of the human body, water corresponds to 50–60% of its weight [2]. Water is fundamental to humanity for its role in hydration and homeostasis, among others. Water is also required for sanitation, culture, religion, medicine, agriculture, animal production, food industry, manufacturing, energy generation, maintenance of ecosystems, and biodiversity.

Groundwater is the main source of the planet’s available water resources, essential to the hydrological cycle and sustaining river and terrestrial ecosystems. Groundwater is widely used throughout the world as a source of drinking water, mineral–medicinal water and for irrigation of crops (agriculture), industrial processes, domestic life, and mining [3,4]. Although most of the planet is covered by water (≅70%), only 2.5% is freshwater, of which 30% is groundwater and the rest is in the form of ice in glaciers and permafrost [3]. Considering this, the amount of fresh water that is accessible is limited, which makes it an exhaustible and precious resource [5]. Nevertheless, overexploitation and pollution have increased the vulnerability of these systems [3].

The climate crisis has had a negative effect on the hydrological cycle and water resources, which have been depleted and polluted, disrupting socio-ecological systems [6]. Groundwater is increasingly vulnerable to drought and desertification scenarios [7]. However, in the face of decreasing water availability, the proper use and management of aquifers can be an alternative for sustainable water use and adaptation to climate change [8,9,10].

Groundwater contains a dilution of the minerals found in sediments or rocks present in the aquifers that give them particular physicochemical characteristics [4]. On the other hand, these waters are very vulnerable to contamination by infiltration and percolation of microorganisms such as pathogens from sewage and chemicals such as heavy metals, medicines, agrochemicals, hydrocarbons, and microplastics [11,12,13]. The presence of these components of geogenic, biogenic, or anthropogenic origin, including emerging contaminants or pathogens, implies health risks for the people who consume them [14].

Despite the importance of groundwater, there is much unknown about it. For that reason, it is essential to understand aquifers and manage them sustainably to ensure reliable sources of freshwater [15]. This requires hydrogeochemical studies using advanced technological tools to better understand groundwater distribution and dynamics, as well as assessments of water quality and vulnerability to pollution and climate change, with a holistic approach to water resource conservation and management [12,14,16].

Colombia is a country in South America that particularly stands out for its biological diversity, topography, and water resources, providing 5% of the planet’s surface water resources [17,18,19]. It is estimated that the country’s groundwater reserves amount to approximately 5848 km³, distributed over 16 hydrogeological regions, within which there are 61 aquifers, many of which have not yet been studied [17,20,21]. In the face of the global climate and environmental crisis, Colombia’s water resources are not only important for the country, but also for the world. In this sense, the technical guidelines of the Colombian National Government for 2022–2026 establish a policy for integrated management of water resources, which includes the protection of groundwater sources [22]. In the face of these challenges, it is necessary to promote and intensify hydrogeological research, using integrated methodologies to assess and monitor the health and sustainability of aquifers [21].

This review presents an overview of the concepts of aquifers and groundwater due to their importance as natural sources. These water resources facilitate resilience to climate change and ecosystem protection. For that reason, the characteristics of mineral waters, their uses, risks, control policies, and the management of this water resource were examined. Finally, the importance of groundwater in Colombia was highlighted.

2. Aquifers

Aquifers are geological formations or subway layers of rock, sediment, or soil that contain and diffuse groundwater [3]. In this sense, groundwaters are those that lie below the Earth’s surface and encompass the spaces between the rocks and sediments. In the hydrological cycle of the planet, aquifers are essential constituents that play a fundamental role in the supply of water for different uses, such as domestic, industrial, energy, recreation contexts, etc. They also play a crucial role in sustaining ecosystems and supplying rivers and streams during periods of drought [23]. A relevant aspect in the maintenance of aquifers is the replenishment of water through a process called recharge, mainly from precipitation that infiltrates the ground. Meanwhile, groundwater can be discharged naturally into surface water bodies such as rivers and lakes or extracted through wells [3,4,24].

2.1. Types of Aquifers

Aquifers consist mainly of sediments and rocks of varying structure and composition. Sedimentary aquifers are rich in silicates and carbonates, and/or siliciclastic or carbonate rocks of different sizes and structures including grains, matrices, pores, and mineral sediments [25]. Aquifers can be classified into one of the three types, or into several at the same time (multi-layered aquifers), as shown in Figure 1, according to their geological and hydraulic characteristics, such as the type of rock, its degree of heterogeneity, permeability, porosity, depth, and hydraulic conductivity [25,26].

2.1.1. Unconfined or Shallow Aquifers

Free aquifers are characterized because they have a water table (the upper limit of groundwater) that is not covered by an impermeable layer (confined) and their active flow is often directly influenced by local precipitation and surface water for recharge (see Figure 1). Being the most exposed permeable layer or level with the environment, these aquifers are often exposed to physical, chemical, biological, and microbiological contamination [5,27].

2.1.2. Confined Aquifers

A confined aquifer is a type of geological formation that includes groundwater interspersed with impermeable layers, i.e., both above and below it is covered with material that prevents the movement or outflow of water, for example, bedrock, clay soil, or highly compacted sediment [3]. Confined aquifers, given the depth at which they are located and the characteristics of their layers, are under pressure, which means that when an extraction is carried out by means of drilling, the water is pumped to the surface by itself, forming what is called an artesian well [4,25]. The way in which confined aquifers are recharged is slower than other types of aquifers due to the size of the pores and the compaction of the layers; however, it can occur at certain depth levels where the layers are a little more predisposed to rain or surface water, as in the case of unconfined aquifers [27].

2.1.3. Intermediate, Semi-Confined, or Leaking Aquifers

Intermediate aquifers are often referred to as semi-confined or leaky aquifers. These are aquifers with a confining layer above or below, but not in both locations. Therefore, they could be considered to have aspects characteristic of both confined and unconfined aquifers (see Figure 1). The presence of a single impermeable layer may partially restrict groundwater movement, but it is not as pressured as a fully confined aquifer. Like free aquifers, the mode of recharge of intermediate aquifers is from precipitation and surface water sources [4,27].

3. Groundwater

Groundwater is the term used for naturally occurring water that is at various depths below the Earth’s surface in the spaces between rock, sediment, or soil particles. It is also an essential component of the water cycle and may be present in unconfined aquifers, confined aquifers, intermediate aquifers, or other geological formations [28]. Groundwater encompasses all groundwater, regardless of its location or geological characteristics, including in a vadose zone (unsaturated zone) and a saturated zone (where all available spaces are filled with water) [29].

Groundwater occupies the largest percentage (29.7%) of the accessible water on Earth. However, an alarming fact is that most of this water is polluted, leaving about 1% for daily use [30]. A key aspect to support the recovery of these waters is to know what their natural properties are, i.e., biological, physical, and chemical properties that give them a distinctive value compared to other waters and, in addition, mark a starting point that helps to compare and evaluate pollution and its origins [31].

3.1. Colombian Grounwater

Colombia has significant groundwater reserves, which has led to an interest in understanding these resources, their uses, and their current state. However, relatively few studies have been conducted on this topic. The Institute of Hydrology, Meteorology and Environmental Studies (IDEAM), as an institution under the Ministry of Environment and Sustainable Development (MADS), has characterized Colombia’s groundwater and aquifers, providing insights into the distribution of hydrogeological provinces, aquifer systems in the country, and the development of strategies that contribute to assessment and management [32,33].

Colombia has five major hydrographic areas (Amazon, Caribbean, Magdalena–Cauca, Orinoco, and Pacific). In these hydrographic areas are 16 hydrogeological provinces, which are delimited by tectonostratigraphic units, and 61 multi-layered aquifer systems (see Figure 1) [21,33]. It is estimated that in these provinces, there is approximately 5848 km³ of groundwater reserves in the country, with 52% of these located in the Amazon and Orinoquia provinces [19,20,33].

Colombia’s aquifer systems contain over 130 aquifers with a wide variety of characteristics (see Figure 2), including unconfined, semi-confined, and confined types, with diverse physicochemical properties that support various water types [4,33]. Most of Colombia’s aquifer systems are in the Magdalena–Cauca and Caribbean hydrographic regions, which are the most densely populated in the country [20,21,33]. However, most of the knowledge about them needs to be improved; the least studied are those found in the Amazon, Orinoco, and Pacific regions [21,29]. Many of Colombia’s aquifer systems have been overexploited and polluted [21,34,35,36].

In addition to the IDEAM work, some research has been carried out on the dynamics between surface and groundwater [37,38,39]. The Magdalena–Cauca hydrographic region is an exciting large area whose studies reveal a complex interaction of groundwater and surface water, requiring further studies and new technologies [40,41].

In the Middle Magdalena, it has been observed that the dynamics of water flow are influenced not only by surface waters, but that there are seasonal variations throughout the year, which still need to be better understood [42]. In the Aburrá Valley, groundwater flow is lateral in areas with great population expansion, requiring further studies on the impact of these areas on water dynamics [38].

Wetlands are significant and important biodiversity refuges in Colombia, where there are 31,702 known wetlands distributed throughout the country and which have suffered a negative anthropogenic impact [37]. These wetlands have a dynamic of recharge, transit, or discharge of aquifers, but only in some of them, located in the Cauca–Magdalena hydrogeological system, have they been studied or have information about this relationship [21]. Climate change has effects on groundwater recharge [38], and in Colombia, it has been seen how climate phenomena have had effects on the state of wetlands and groundwater [21,36]. To know the true state of groundwater and the maintenance of ecosystems, it is important to characterize the aquifer recharge process [38]. Only some evaluations have been carried out, such as the aquifers of the Bogotá savannah, Cauca, and the Middle Magdalena Valley [21,35,39,43].

Most of the studies on groundwater in Colombia focus on water management, its usage, and its quality, particularly in regions of demographic, agricultural, and industrial importance [41,44,45,46,47]. These studies reveal the degradation of water quality [43,46,48,49,50,51], the depletion of water resources in arid and impoverished areas [44], and the utilization and management of these waters [44,45,48,52]. Therefore, it is essential to increase the study of groundwater to ensure a safe and sustainable water supply in the country, as well as to address the challenges associated with contamination and the industrial and agricultural use of these resources.

Although Colombian public policies seek the availability of drinking water and basic sanitation for the entire population, at least 25% of the population does not have adequate access to drinking water, with the rural population being the most affected by the absence of aqueducts [53]. Therefore, for many rural populations, groundwater is an alternative to accessing water through deep wells, which subsist on the use of this water for consumption without being treated [54]. However, many of these waters have not been analyzed to determine their microbiological and physicochemical characteristics or to determine their safety or risks, making these populations vulnerable. Some studies indicate that some groundwater is not suitable. In groundwater from rural areas of the Department of Meta, coliforms, phosphorus, and nitrate were determined in ranges not permitted for consumption [49]. In sugar cane-producing areas, an alteration in the quality of groundwater has been determined due to the discharge of residual vinasse from the production of ethanol derived from the cane industry [52]. In groundwater used for consumption located in the rural municipalities of Margarita and San Fernando, department of Bolívar, on the banks of the Magdalena River, the presence of arsenic was detected in concentrations above the reference values [51]. In the northern region of La Guajira and Cesar, the quality of groundwater has been evaluated, and microbiological contamination with pathogenic bacteria and protozoa has been found [50]. On the other hand, human activities, mainly mining, put aquifers at risk, not only due to contamination but also due to exploitation and alteration of recharge processes, making them increasingly vulnerable [44]. The presence of various chemical and biological agents in groundwater may be typical of the nature of the subsoil. However, contaminating elements have been identified. Therefore, it is essential to do more research using advanced methodologies, as well as groundwater management to guarantee conservation, sustainable use, and safety if used for consumption.

Likewise, it is necessary to carry out more research related to recovery and management strategies for aquifers and groundwater. In this sense, the diversity of Colombian ecosystems and biological species is a source of possible solutions based on nature. One example is the use of magnetotactic bacteria to remove metals such as iron and manganese [55].

Given its water resources, Colombia is a world water power, where a large part of the reserves are made up of groundwater. For this reason, it is necessary to pay more attention to Colombia’s groundwater, controlling overexploitation and contamination, and establishing public policies and research that promote its recovery, conservation, monitoring, management and sustainable use, as well as the development of new technologies.

3.2. Biological Propierties of Groundwater

Groundwater has a series of biological properties that contribute to the homeostasis of the natural system. These properties refer to the organisms, microorganisms and ecological processes that develop in them. Although, groundwater may give the impression that it is a completely isolated environment, and, therefore, there may be limitations to the generation of diverse and active environments; on the contrary, it can host varied and unique ecosystems [56].

Macroscopic subterranean biological biodiversity includes species of small invertebrates, fish, amphibians, and other types of aquatic organisms that possess high adaptive characteristics [57,58]. For example, in the absence of light, they may lose their eyes and pigments and develop greater sensitivity in their structure; they may have more excellent resistance to low pressures or greater tolerance to the low oxygen levels present; and given the scarcity of nutrients, they may opt for modified feeding behaviors that result in a low metabolic rate and resistance to starvation [59,60,61]. Likewise, a variety of microorganisms, such as fungi, protozoa, bacteria, and archaea, live in such environments, fulfilling essential roles in nutrient cycling, decomposition of organic matter, and transformation of various chemical compounds [62]. Therefore, since subterranean environments can comprise a wide range of diverse organisms and microorganisms, in a biotechnological context, it is beneficial because it could favor the use of these, or of their proteins, genetic elements, and metabolic products that could become of interest in some industries. As an example of this, certain bacteria found in groundwater have developed metabolisms capable of biodegrading pollutants of different natures, thus contributing to purification processes [63,64]; bacteria with insecticidal properties have also been isolated and exploited [65] as well as antibiotic producers [66].

3.3. Physicochemical Properties of Groundwater

Groundwater can encompass a wide range of physicochemical conditions that will depend on the geology of the space where it is found and circulates. These include pH, temperature, turbidity, ions, metals, minerals, among others.

Table 1. Physicochemical properties of groundwater.

Physicochemical Properties	Description
Color	There may be coloration due to the presence of colored organic material or chemical elements that when reacting, generate a certain shade, for example, iron and manganese in water may be red. The color varies according to geological characteristics and can be measured by visual comparison with cobalt standards [67].
Odor	It is variable and dependent on the chemical composition of the water, or the elements that make up the water. Likewise, it is complemented by individual perception [67].
Taste	The result of the taste, in addition to being based on the characteristics of a particular water source, is also the combination of the perception of odor, temperature, and the sensation of the taste [67].
Electrical conductivity	It is related to the concentration of salts in solution, in which dissociation generates ions capable of conducting electric charge. In groundwater, the conductivity may be higher due to the number of ions present [68,69]
pH	It is generally neutral, around 7; however, it depends on the chemical composition of the adjacent rocks and the presence of acids or bases in the medium [70].
Temperature	It is stable and is influenced by the local climate, but tends to be colder than surface water because it is insulated by the ground [71].
Turbidity	Undisturbed water is usually clear with low turbidity because it passes through natural filtration through the ground.
Suspenden solids	They are usually very few, but may be present in unconfined aquifers or during well drilling and development [71].
Total disolved solids (TDS)	They are mainly determined by the geological characteristics of the surrounding environment. TDS are a mixture of organic material and inorganic salts that may be naturally occurring, such as carbonates, chlorides, sulfates, etc., or introduced by anthropogenic contamination [69].
Hardeness	It depends on the concentration of calcium and magnesium in the water. Hard water can cause scaling in pipes, and may require water softening treatments [67].
Contaminants	Contamination is often associated with a variety of sources, including industrial, agricultural or subway storage leaks. Contaminants may include heavy metals, organic pollutants, pesticides and VOCs [72].
Disolved gases	Gases such as O2 and CO2 can be present in water. The former favors the development of aerobic organisms and microorganisms. The latter can be transformed into carbonic acid and modify the pH [71].
Salinity	Salinity is often generated in warm regions or coastal areas. It may be due to the accumulation of salts due to evaporation of water from the Earth’s surface, or by the infiltration of seawater into coastal aquifers [67].
REDOX reactions	Redox conditions are influenced by the availability of different chemical species in the water, the presence of organic material, and microbial activity [73].
Dissolved oxygen	It is an indicator of biochemical processes carried out by organisms and microorganisms in the presence of organic matter. The concentration of dissolved oxygen in groundwater can differ according to depth, pressure, and temperature. Both saturated and anoxic zones can occur [67].
Alkalinity	It is the index of the buffering capacity of water to neutralize the acids present. In groundwater, this capacity is given mostly by carbonates, bicarbonates and hydroxides [69].
Ions	The most common ions in groundwater include [67]: Cations: calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), iron (Fe2+, Fe3+), manganese (Mn2+) and ammonium (NH4+). Anions: sulfate (SO42−), chloride (Cl−), bicarbonate (HCO3−), nitrate (NO3−), carbonate (CO32−), fluoride (F−), phosphate (PO43−), cyanide (CN−) and silicate (SiO32−). The interactions and concentrations of these in water differ according to the geology and conditions determined in each area.
Metals	Some metals can be naturally occurring or introduced, some of these are: copper, chromium, cadmium, manganese, arsenic, lead, copper, zinc and mercury [74].
Minerals	The presence of one mineral or another, or the combination of several will depend on the geological conditions of the environment where the water moves. Some of the minerals that can be found in groundwater include: calcite, gypsum, dolomite, quartz, feldspar, iron oxides, manganese oxides, arsenopyrite, realgar, orpiment, phyllosilicate, and selenite [67].

shows a series of general characteristics associated with the physicochemical properties of groundwater.

3.4. Groundwater Contamination

Groundwater is typically clear and clean because the soil naturally filters out particles. However, this same process can result in the dissolution of natural mineral deposits within the Earth’s crust, which has a geogenic origin [12]. Groundwater contamination is defined as the introduction of undesirable substances into groundwater due to human activities, which have an anthropogenic origin. These contaminants, such as toxic metals, hydrocarbons, organic pollutants, pesticides, nanoparticles, microplastics, and other emerging contaminants, pose a threat to human health, ecological services, and sustainable socioeconomic development [12,75]. Groundwater contamination differs from surface water contamination in that it is invisible. Contaminants in groundwater are often colorless and odorless, with negative impacts on human health, leading to chronic diseases and, in some cases, being difficult to detect [76].

In recent decades, scientists have developed sophisticated and highly successful techniques for removing many contaminants from water. The removal of contaminants from groundwater is typically addressed by drilling water wells, pumping the contaminated water to underground facilities for various treatment approaches, such as air stripping and treatment towers, and granular-activated carbon (GAC). Pressurized air bubbles are also used to treat contaminated groundwater. The selection of an effective treatment/remediation method depends on the characteristics of the contaminants and the media, as well as the available reactive materials [77]. To delve deeper into the topic of groundwater treatment, there are studies that delve into groundwater contamination and remediation models [77,78].

The number of contaminants detected in groundwater has significantly increased in recent years. Depending on the nature of the contaminant, they can be classified as chemical, biological, or radioactive contaminants. Among the main contaminants of groundwater are seawater and brackish water. These natural sources can become serious sources of contamination if human activities disrupt the natural environmental balance, such as the depletion of aquifers leading to the intrusion of saltwater, particularly in coastal cities [12]. The overexploitation of soils due to intensive agriculture has led to an increasing presence of nitrogen contaminants, such as nitrate, nitrite, and ammonia nitrogen. Nitrate primarily originates from anthropogenic sources, including agriculture (such as fertilizers and manure) and domestic wastewater [79,80]. Other common inorganic contaminants found in groundwater include anions and oxyanions such as F⁻, SO₄²⁻, and Cl⁻, as well as major cations like Ca²⁺ and Mg²⁺. Total dissolved solids (TDS), which refer to the total amount of organic and inorganic compounds in water, can also be elevated in groundwater. These contaminants are often of natural origin, but human activities can also increase their levels in groundwater [81].

Potentially Harmful Metals (PHMs) in sources of potable groundwater are a commonly reported environmental issue [82]. Chemical elements widely detected in groundwater include metals such as zinc (Zn), lead (Pb), mercury (Hg), chromium (Cr), and cadmium (Cd), as well as metalloids like selenium (Se) and arsenic (As) [74]. The presence of Potentially Harmful Metals (PHMs) in groundwater can have a geogenic origin due to factors such as lithology, hydrodynamic conditions, mineralization of the watersheds, and water–rock interactions, including mineral dissolution, ion exchange, and redox processes. However, human activities can also contribute to the presence of these metals in groundwater, either through industrial processes, agricultural practices, or other anthropogenic sources. It is essential to understand both natural and human-induced factors when assessing and managing groundwater quality and potential contamination by PHMs [12,74,83]; indeed, the high concentration of Potentially Harmful Metals (PHMs) in groundwater sources is primarily attributed to mining activities, the discharge of industrial wastewater, and pesticide usage. However, PHMs in groundwater can also increase due to a low hydraulic gradient, resulting in reduced water infiltration, or in arid climates where evaporation leads to metal accumulation [84,85].

In groundwater, more than 200 organic contaminants have been detected, and this number continues to increase [12]. This group includes pesticides, veterinary products, food additives, nanomaterials, industrial compounds, halogenated solvents, personal care products, and pharmaceutical residues. Recently, attention has been focused on the detection of the latter due to their high persistence in the environment [86]. Many of these compounds may not have direct toxic effects on living organisms, but they can reduce the levels of dissolved oxygen in groundwater. On the other hand, halogenated compounds (chlorinated, brominated, fluorinated) are stable in the environment and can accumulate in organisms, leading to harmful effects in higher trophic level organisms [12]. Organic contaminants in groundwater are traditionally classified based on their use [87] instead of their occurrence, transport, or environmental impact. However, it can sometimes be extremely difficult to assign certain compounds to a particular group, as they may belong to more than one category. The presence of organic contaminants in groundwater is poorly characterized, and understanding their temporal and spatial variation remains a priority [86].

4. Mineral–Medicinal Groundwater

Natural mineral waters come from springs or wells that are supplied from geologically and physically protected mineral-rich aquifers, springing from one or more natural (or borehole) sources. For a water to be considered a natural mineral water, it must contain no less than 250 parts per million (ppm) of total dissolved solids (TDS), which are mainly dissolved minerals, salts, and trace elements, such as calcium, magnesium, potassium, and sodium [88].

When a mineral evaluation is carried out on the water and minerals with therapeutic potential are recognized, these waters are called “mineral-medicinal”. Some studies believe that compounds such as sulphate, bicarbonate, calcium, and magnesium present in mineral water have health benefits like improving digestion [89,90,91,92,93] mainly due to the direct action of mineral waters on the intestinal epithelium, generating an accelerated process of epithelial renewal, without epithelial disruption [94]. Other benefits of mineral water consumption include improved gastric emptying [95], gastroduodenal peristalsis [96], dyspepsia [97], the activity of the bile ducts [98,99], cholagogue activity [100], increased mineralization [101,102], and a reduction in bone resorption [103]. Studies on mineral water consumption show that frequent intake of mineral water can have health effects on biomarkers of cardiometabolic risk, especially reducing total cholesterol, fasting glucose, and LDL cholesterol [104,105], and the formation of kidney stones [106].

In a rodent model of metabolic syndrome, mineral-rich water intake prevented increases in heart rate and plasma triacylglycerols [107]. In pregnant women with iron deficiency anemia, iron-rich mineral waters can be an alternative to ferrous sulphate tablets, as lower doses of iron are needed, thus avoiding the unpleasant side effects of iron therapy [108].

There are many sources of mineral waters worldwide, and due to their mineral–medicinal properties, several countries market these waters. Europe is a continent abundant in natural mineral waters [109], and there, some countries such as Spain, Slovakia, Romania, Germany, and France bottle and market them for consumption [102,110]. In Italy, these waters are mainly used for recreational purposes [111]. North America also has an abundance of mineral waters; however, the geological characteristics of the formations containing these groundwaters differ from the European continent. In fact, some studies have found that European mineral waters have much higher calcium content compared to American mineral waters [102,112,113].

In terms of ecosystem diversity and environmental wealth, Colombia has always stood out in the world. Hydrogeologically, it has also proven to be diverse [19,114]. This is conducive to the study of the evaluation and exploitation of groundwater with possible mineral potential. The importance of these resources lies in their medicinal and tourist potential, which could benefit the economy and the health of the population [115].

In different regions of Colombia, aquifers from hot springs and mineral waters emerge, which have been popularly and traditionally used for tourism as medicinal waters. These include: the Chocó hydrogeological region; the Nuquí hot springs; the Eastern Cordillera region; the Paratebueno and Machetá hot springs; the Cauca–Patía region; the Santa Rosa de Cabal hot springs; the Bajo Magdalena region; the Ciénaga hot springs; the Cesar–Ranchería region; the Becerril hot springs; the Sinú–San Jacinto region; and the Usiacurí mineral water wells [20,115,116]. However, it is important to highlight that the lack of expert studies evaluating the properties of these waters, both nationally and internationally, makes it difficult to determine their potential uses and possible associated risks in the Colombian context.

Therefore, extensive research on mineral waters is needed to fully understand their properties, potential uses, and associated risks. This would allow us to not only to maximize their therapeutic benefits, but also to establish safe guidelines and regulations for their use. In addition, the implementation of monitoring programs could be considered to ensure the quality and safety of these waters, both for the health of consumers and for the long-term sustainability of this resource. On the other hand, it would be valuable to explore possible synergies with the scientific community and health experts to develop specific treatment protocols and to promote responsible and conscious use of these waters in the therapeutic and tourism sectors.

5. Classification of Mineral Waters

Mineral waters, due to their geological nature, contain a variety of chemical substances or species, mainly due to the high solvent and reactive capacity of water. In reality, there is no single classification of mineral waters; however, the European Parliament and the Council of the European Union (Directive 2009/54/EC) established a classification of mineral waters based on the amount of residues present after the evaporation of one liter of water. Mineral waters are classified into; (a) oligometallic or weakly mineralized, those with up to 500 mg/L of dry residue; (b) very weakly mineralized, those with up to 50 mg/L of dry residue; (c) strongly mineralized, those with more than 1 500 mg/L of dry residue; (d) bicarbonated, those with more than 600 mg/L of bicarbonate; (e) sulphurous, those containing more than 200 mg/L of sulfates; (f) chlorinated, those containing more than 200 mg/L of chloride; (g) calcium, those containing more than 150 mg/L of calcium; (h) magnesium, those containing more than 50 mg/L of magnesium; (i) fluoridated, or containing fluorine, with amounts greater than 1 mg/L of fluorine; (j) ferruginous, or iron-containing, containing more than 1 mg/L of bivalent iron; (k) acidified, those containing more than 250 mg/L of free CO₂; (l) sodium, those containing more than 200 mg/L of sodium [117].

There are other criteria used to classify the different types of water, such as physico-chemical analyses (temperature, density, pH, radioactivity, etc.), chemical analyses (ozone, sulphhydrometric grade, dissolved gases, etc.), or organoleptic characteristics (color, taste, limpidity). In terms of pH, mineral waters are classified as acidic water (pH below 7) or alkaline water (pH above 7). By temperature, mineral waters can be cold (temperatures below 20 °C measured in situ), hypothermal (20–30 °C measured in situ), mesothermal (30–40 °C measured in situ), and hyperthermal (temperatures above 40 °C measured in situ). Hardness indicates the presence of alkaline earth metals, and mineral waters can be very soft (0–100 mg/L CaCO₃), soft (100–200 mg/L CaCO₃), hard (200–300 mg/L CaCO₃), or very hard (with values above 300 mg/L CaCO₃) [109]. According to the osmotic pressure or cryoscopic drop (∆), they can be hypotonic (∆ lower than −0.55° C), isotonic (∆ between −0.55 and −0.58 °C), and hypertonic (∆ higher than −0.58 °C) [118].

On the other hand, a classification of these waters is given by the mineral state that prevails in it. They can be:

5.1. Waters with More than One Gram per Liter of Mineralizing Substances

A mineral water is one with a dry residue greater than 1 g/L, or without a residue of more than 1 mg/L of lithium, 5 mg/L of iron, 5 mg/L of strontium, 1 mg/L of iodine, 2 mg/L of fluorine, 1.2 mg/L of silica, etc. If the dry residue information is not available, the total dissolved solids (equal to the sum of anions and cations), in excess of 1 g/L, can be used.

• Sulfated: sulfate anion predominates, and its therapeutic properties are strongly influenced by other ions such as sodium, magnesium, bicarbonate, and chloride [119].
• Chlorinated: the chloride ion is usually accompanied by sodium in a similar proportion. The composition of this type of water reflects a deep origin and the presence of past seas. The occurrence of faults and cracks facilitates its rise to the surface. They are subdivided into sources: (>50 g/L), medium (between 10 and 50 g/L) and weak (<10 g/L).
• Bicarbonated: the bicarbonate ion is accompanied by calcium, magnesium, sodium, chloride, and others. When these waters have a large amount of free acids (CO₂, >250 mg/L), they are also called carbonated or carbogaseous [119].

5.2. Waters with Less Than One Gram per Liter of Mineralizing Substances

Waters with this condition are known as oligo-mineral waters. In this type of water, microelements such as cobalt, vanadium, molybdenum, silicon, etc., may be present. Within the classification, there are two subgroups, one of low (<0.2 g/L) and one of medium mineralization (from 0.2 to 1 g/L), but without being considered special mineralizing causes. Those of medium mineralization, depending on the temperature, can be acratopegas (less than 20 °C) or acratotherms (more than 20 °C) [119,120,121].

5.3. Waters with Special Components Recognized for Their Biological Activity in Certain Proportions

Mineral waters are also considered to be those that have certain components of recognized biological action, and whose concentrations are established by standards (

Table 2. Classification of mineral waters with biological activity according to their composition.

Water Type	Formula	Established Range
Silicic	SiO2	>50 mg/L
Arsenicas	As	From 0.2 to 0.3 mg/L
Boric	Ba	>4 mg/L
Fluorics	F−	From 1.0 to 2.0 mg/L
Bromics	Br−	>4 mg/L
Iodhydric	I−	>1 mg/L
Lithics	Li	>1 mg/L
Strontium	Sr	>10 mg/L
Barium	Ba	>5 mg/L
Ferruginous	Fe+2; Fe+3	>5 g/L
Radonics	Rn	>1.82 nCi/L

) [119].

6. Uses Associated with the Consumption of Mineral Waters

Both ground and surface mineral waters have been widely used by mankind since prehistoric times [122] as a vital resource for the development of life; they have allowed not only the survival of the species but also social growth and an impact on the economy of the populations [123,124,125].

A clear example of this is the use of water in agriculture for crop irrigation, a practice that has increased worldwide in recent decades due to the growing demand for food and decreasing rainfall [126,127]. In addition, groundwater can be rich in nutrients and minerals, which can improve crop quality and promote plant growth [65]. In this sense, the use of mineral waters represents an economic impact in the regions where this resource is enjoyed, proposing models of sustainable agriculture [123]. On the other hand, authors focus on the consequences that the exploitation of agriculture has generated on the environment, precisely generating the contamination of groundwater by the presence of pollutants such as pesticides, and evaluate how this impact can lead not only to environmental but also economic consequences [124].

Among the other ancestral uses of subway mineral waters is also recreation, as in the case of spas and health resorts. These tend to be popular all over the world due to their healing and relaxing properties, since these waters can be rich in minerals such as calcium and magnesium, which can be beneficial for the skin and hair [104,128]. Although, the use and benefits in humans are not limited to recreation and they also include consumption, as mineral water is established as a source of drinking water. This is possible if the properties of mineral water consumption are analyzed, and the quality parameters and purification requirements are carried out. Some sources of useful trace elements for people are iron, fluoride, calcium, magnesium, zinc, among others, and these can contribute to medicinal and therapeutic processes [102,129].

For consumption, wells have been identified from which water can be consumed directly, a common practice in rural communities where access to manufacturing processes is limited and where ground mineral water can be considered an important source of drinking water for the populations, even more so if the surface water supply is scarce in the area [130,131]. In favor of industrialization in other regions, bottling companies comply with water purification and quality assurance processes, reaching the mass distribution of water [132].

On the other hand, mineral waters have been used for raising livestock where wells are considered as a source of water suitable for livestock use and are very profitable considering the economic impact generated using natural waters, which in turn, can be a source of micronutrients and minerals that can be used by the animals raised [133].

Another reported use is in the mining area, where due to the proximity, groundwater is used for mining processes; however, this tends to generate a problem, since the water used in these processes becomes a major pollutant, known as “mining contact water” or mining tailings, which is nothing more than water that carries high amounts of minerals and toxic compound waste from mining. This is reported for the known negative impact it generates to the environment, contaminating aquifer connections that can supply drinking water to regions, and also generating toxic environments for nearby fauna [134,135].

7. Risks Associated with the Consumption of Mineral Waters

Throughout history, mineral waters have been recognized for their healing properties, which has generated considerable interest in evaluating their effects on human health and the possible risks associated with their consumption. Among the studies carried out, special attention has been paid to the cardiovascular and gastrointestinal benefits derived from mineral water consumption. Bicarbonated mineral water could have a positive impact on cardiometabolic risk markers, including lower levels of total cholesterol, fasting glucose, and LDL-cholesterol [106,136]. On the other hand, mineral water rich in magnesium and sulfate have shown significant benefits in the treatment of functional constipation [137].

However, it is important to also consider the potential risks associated with mineral waters. Just as mineral waters can contain a wide variety of minerals important to the functioning of the human body, such as calcium and magnesium, they can also contain other highly toxic minerals.

In discussing these risks, it is essential to consider the factors associated with health effects. These risks may include chemical contaminants, the presence of microplastics, and biological pathogens.

7.1. Chemical Contaminants

Primary metals, also known as trace metals, such as iron (Fe), copper (Cu), zinc (Zn), selenium (Se), and nickel (Ni), play specific roles in the body’s metabolism [138]. In contrast, there is no defined function in the body for non-essential metals, commonly known as heavy metals, chromium (Cr), cadmium (Cd), mercury (Hg), manganese (Mn), lead (Pb), and arsenic (As) [139]. It is important to note that exposure to high concentrations of heavy metals can pose a risk to human health [140].

One of the crucial aspects to consider when evaluating mineral waters are the possible risks associated with the presence of chemical contaminants (see Figure 3). Among these, arsenic stands out for its high toxicity to humans [141]. Arsenic, in different organic and inorganic forms, can be present in mineral waters [142,143]. However, the forms of arsenic present different degrees of toxicity, such as monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), as end products of arsenic metabolism, are less harmful compared to the inorganic form of arsenic [141]. Arsenic has been shown to be a potent carcinogen that can cause cancers of the skin, bladder, liver, and lung [144,145].

Regarding other metals, it has been observed that copper (Cu) can cause liver and kidney damage [146]. Lead (Pb) has been associated with brain disorders and gastrointestinal colitis [138,146]. Cadmium (Cd) has been linked to bone disorders (known as Ita-Ita) and cardiovascular diseases [147,148]. Zinc (Zn) can influence the level of acidity in blood vessels, increase oxygen uptake, and elevate heart rate [149]. Finally, it has been suggested that cobalt (Co) and chromium (Cr) may be associated with certain types of cancer in humans, including blood and bone cancers [150]. Recent research suggests that some clinical symptoms caused by exposure to heavy metals in drinking water may occur even at concentrations below the established standard limits [138]. This reality highlights the importance of considering the possible risks associated with the presence of chemical contaminants in mineral waters.

Lithium is considered a therapeutic agent to treat chronic neurodegenerative diseases such as Alzheimer’s, Parkinson’s, and Huntington’s disease [151,152]. Some mineral waters naturally contain this element [152]. However, it is important to note that lithium levels in water have been associated with a possible increased risk of autism spectrum disorder during pregnancy [153].

Some elements that provide benefits to human health, such as fluoride, should be consumed in low concentrations. The presence of high concentrations of F- in water is associated with fluorosis [154]. It has been shown that people residing in areas with elevated fluoride levels may experience regional fluorosis, which can trigger problems such as skeletal fluorosis, bone cancer and neurotoxic effects [155,156,157].

On the other hand, excessive use of fertilizers can result in elevated concentrations of certain chemical compounds, such as nitrates and nitrites, in mineral waters [158]. This is important because of its relation to pathologies such as blue baby syndrome in the case of nitrates [154]. In addition, it has been reported that the ingestion of nitrates and nitrites, in situations leading to endogenous nitrosation, may have carcinogenic properties [158].

7.2. Microplastics

Microplastics are plastic fragments with diameters of less than 5 μm and can be classified into primary and secondary microplastics [159]. They are commonly formed when plastic waste is released into nature, and it undergoes a degradation process that reduces it in smaller sizes. Primary microplastics are those that are produced directly in this size range, while secondary microplastics come from the fragmentation of larger objects due to exposure to solar ultraviolet radiation, as well as chemical and physical processes and mechanical wear and tear [160,161].

A large amount of plastic waste is discarded in rivers, surface water bodies, oceans, and landfills due to the increase in global demand for plastics [162,163]. In addition, there is atmospheric micro and nanoplastic that is exchanged with the ocean, which denotes a complex dynamic [161,164] and must be interacting with groundwater. These wastes undergo decomposition processes driven by biological and environmental factors, resulting in the generation of even tinier particles that eventually infiltrate groundwater [13,162,164].

These tiny plastic particles not only have an impact on the environment but can also affects various systems in the human body, such as the respiratory system, the digestive system, and the endocrine system [165]. Microplastics can induce alterations in the intestinal microbiome, generating an imbalance between beneficial and harmful bacteria, potentially triggering various gastrointestinal symptoms such as abdominal pain, bloating and changes in bowel habits [166]. Thus, the presence of microplastics in water is a cause for concern, as it can result in the ingestion of these particles which can generate detrimental effects on human health.

7.3. Pathogenic Biological Agents

Nearly 50% of the world’s drinking water supply comes from groundwater sources, which is due to their lower exposure to contamination, pathogen ingress, and evaporation, making them a more reliable and suitable source for supply compared to surface water [167,168].

Groundwater harbors a wide diversity of microorganisms, including viruses, bacteria, and parasites. Contamination with fecal matter is of particular concern, as it can be a source of significant gastrointestinal infections in humans, such as cholera, salmonellosis, and shigellosis [169,170,171]. In addition, other pathogens have been observed to caused outbreaks, including Norovirus, Rotavirus, Campylobacter, Legionella, Giardia, and Cryptosporidium [172,173,174,175].

Some studies have been carried out to evaluate the survival of these microorganisms in mineral waters [176,177,178]. For example, it has been observed that strains such as Bacillus megaterium and Staphylococcus can survive for 10 to 100 days in groundwater [178]. The ability of microorganisms to colonize springs and mineral water bottling plants has been described previously, and this represents a major health risk for consumers of mineral water [170]. Therefore, it is important to evaluate and maintain the necessary conditions, stipulated by the regulations, in order to avoid illnesses or health problems due to the consumption of these waters.

8. Groundwater Exploration and Analysis

Groundwater plays a crucial role in drinking water supply, irrigation, sustainability of wetlands and rivers, as well as in temperature regulation and adaptation of ecosystems to climate change, among other things [179,180]. Global monitoring of these waters is carried out by measuring factors such as water level (water table), extraction rates and percentages, spring discharges, and water quality. Groundwater level measurements are often interpolated and combined with other data, such as remotely sensed information and mathematical models, to assess the status of these water resources [121].

Not all Latin American countries have a water law that is adapted to their needs and territorial characteristics, if they have one. This is due to the fact that, frequently, groundwater is given little consideration or is left to the decision and dynamism of the citizens without any type of regulation, protection, or planning [179].

Groundwater exploration is a process that involves searching for and locating aquifers and is based on a variety of geophysical, hydrogeological, and sampling techniques in order to identify the location and quality of the water resource [181]. Some of the common techniques include drilling boreholes, observing water tables, using satellite imagery and Geographic Information Systems (GIS) [182,183], and geophysics, which uses methods such as electrical tomography and seismic surveying to map the geological structure of the subsurface [181,184,185]. Once an aquifer has been identified and located, a detailed analysis of the groundwater is performed to determine its quality and supply capacity; this involves the collection of samples and their analysis in the laboratory to evaluate the presence of pollutants such as heavy metals, nitrates, pesticides, or other chemicals that may affect the potability of the water, as well as physicochemical parameters such as pH and electrical conductivity, among others [186,187]. In addition, the monitoring of these aquifers is provided by a framework of meteorological, hydrological, and oceanographic networks that are a fundamental part of the observation, measurement, and surveillance of aquifers [184]. These technologies range from radar and satellite imagery to higher altitude observation systems, radiometers, wind profilers, radiosondes, and ozonesondes [179,188].

8.1. Extraction

Over the last century, freshwater withdrawals from rivers, lakes, aquifers, and artificial reservoirs have increased worldwide. The rate of increase during the period 1950–1980 was high (about 3% per year), due to the higher population growth rate and the exponential increase in groundwater exploitation, especially for irrigation [121]. Groundwater supplies about 30% of all the freshwater abstracted on the planet. However, its consumption and global benefits are greater. Groundwater abstractions are stable in the United States of America (USA), most European countries, and China. Asia has the highest proportion of freshwater withdrawals (64.5%). It is followed by North America (15.5%), Europe (7.1%), Africa (6.7%), South America (5.4%), and Australia and Oceania (0.7%). An analysis of the main sectors of the use of groundwater abstractions shows that 69% of the total volume abstracted is used for agriculture [189], 22% is for domestic use, and 9% is for industrial purposes. However, these percentages vary from continent to continent [121].

Irrigated agriculture consumes 70% of all freshwater withdrawals. Its use for food processing is also significant and amounts to 5% of the total water use [190]. To meet global water and agricultural demand in 2050, there is an estimated 50% increase in demand for food, feed, and biofuels from the 2012 levels [191]. It is important to increase agricultural productivity through sustainable intensification of groundwater abstraction and in turn, to decrease the water and environmental footprint of agricultural production [189]. Groundwater is essential for irrigated agriculture, livestock, and agricultural activities, including food processing. It is estimated that 38% of land equipped for irrigation is supplied by groundwater. The main regions using water for irrigation are North America and South Asia, where 59% and 57% of equipped areas use groundwater, respectively. While in North Africa, it is 35%, and in Sub-Saharan Africa, just 5% [192].

The industry and energy sectors consume 19% of global freshwater withdrawals where groundwater is usually used in places where the amount of surface water available is limited, but also in situations where quality is important. In 2020, 54% of global manufacturing companies reported that non-renewable and renewable groundwater was important to their operations; of these, 46% decreased their groundwater withdrawals compared to 2019, 32% remained the same, and 21% increased. However, it is more profitable for industries to extract surface water, since pumping groundwater with electricity consumes seven times more energy than extracting surface water, and desalination consumes up to an order of magnitude more energy than groundwater extraction [121].

8.2. Groundwater and Aquifer Legislation and Control

Groundwater sustainability is linked to micro- and macro-political issues that influence land and surface water use and is one of the major challenges in natural resource management worldwide. In the early years of the 21st century, the water governance crisis in Ibero-American countries was identified; as a consequence, five fundamental pillars for the management of a country’s water resources were established: (1) the water authority should be at the highest level. It should be neutral and have a medium and long-term vision; (2) the management law should be modern and take into account the availability of water resources. It should incorporate all advances in knowledge; it should recognize that water is a public good; it should be managed exclusively by river basin units and/or aquifers; (3) the availability of adequate human resources, both in terms of quality and quantity, in all cross-cutting areas related to water resources should be ensured; (4) dedicated financial resources should be made available for the implementation of the measures required by the sector; (5) access to information on the various issues related to water resources is reliable, freely available, and publicly accessible [193]. Each country is aware of the problems it faces in managing and controlling groundwater aquifers and has devoted effort and resources to developing legislation to help mitigate the problem [121]. However, some countries and regions have laws that do not reflect current needs and, in some cases, are often contradictory, as they are subject to different interpretations as a result of their ambiguity [194,195].

The World Health Organization (WHO) is the international authority on public health and water quality that leads global efforts to prevent waterborne diseases and advises governments on setting health-based targets and regulations, developing a series of guidelines on water quality, particularly for drinking water, wastewater treatment, and recreational water quality. In addition, it recommends the establishment of health-based targets, that water service providers develop and implement health plans to define risks, that these are avoided in the most effective way, from the time the water is collected until it reaches the consumer, and that independent monitoring is carried out to ensure the effectiveness of these plans and the achievement of these goals [196]. On the other hand, within the Sustainable Development Goals (SDGs), which are the global goals adopted by the United Nations in 2015 to end poverty and protect the planet, SDG6 was established, called “clean water and sanitation”, in which it promotes the use of groundwater and alternative sources, such as wastewater, to ensure a supply of drinking water is available safely, without fecal contamination or contamination by priority chemicals [196,197].

In Colombia, the national policy for the integrated management of water resources (PNGIRH) is the main instrument for the integrated management and establishment of indicators, hydrological monitoring, and lines of action for the management of water resources. In this sense, national entities execute actions to improve monitoring within the institutional framework of the environmental sector; the Institute of Hydrology, Meteorology and Environmental Studies, IDEAM, oversees providing scientific support to the Environmental Information System, by collecting, processing, and analyzing information. This ensures that any decision on environmental matters is properly supported and meets the relevant needs [188]. Hydrological data and information, which is essential to ensure that the knowledge of water resources in each scientific study is closer to reality, are standardized and homogenized. In response to these responsibilities, the Hydrology Sub-directorate elaborated a protocol in 2007 for water monitoring and follow-up, highlighting the surface water observation and measurement component, as a scientific contribution for users in the national productive sector, regional and local environmental authorities, the disaster prevention and response sector, and the community in general. With this, it is intended to guide the monitoring and follow-up of water through water indicators, so that the decisions to be taken by the national, departmental, and local governments are supported by data and information duly standardized from its origin, to have a better description of the state and projection of the country’s water resources [188]. Furthermore, Decree 1076 of 2015 from the Environment and Sustainable Development Sector of Colombia states that aquifer recharge zones are considered strategic ecosystems, as well as tools for the planning, organization, and management of the country’s aquifers [198]. This framework encompasses stages of preparation, diagnosis, formulation, execution, and monitoring, supported by a methodological guide for the formulation of environmental management plans for aquifers [199].

Drinking waters are those that are considered fit for human consumption, are used for drinking, and can have a nutritional function, it is of vital importance that they are pathogen free, colorless, and odorless, and have relatively low temperatures and dissolved mineral contents below the maximum levels established by the corresponding standard. Given this, drinking waters can be classified into two types: directly potable, which are those whose physical, chemical, and microbiological conditions do not exceed the established limits, and sanitary tolerable, which are those that exceed some of the established limits, but do not contain toxic or radioactive substances, nor fecal contamination or pathogenic germs. In Colombia, Decree 2115 of 2007 establishes characteristics and frequencies of the control and surveillance system for the quality of water for human consumption, which establishes the chemical, physicochemical, and microbiological characteristics with which water for human consumption must comply, including the maximum permitted value for each of these characteristics [200]. On the other hand, the standards for waters for recreational use are established in article 42 of resolution 1618 of 2010; this is understood as waters for primary contact, such as swimming and diving, and secondary contact, such as nautical sports and fishing [201,202].

Mineral waters have been found to have a direct relationship with temperature, flow rate, microflora (saprophytic), and chemical composition. Mineral water standards generally stipulate a concentration of more than one gram of dissolved minerals per kg of water, or of special components above certain proportions established directly by each region. Restrictions regarding temperature and the presence of pathogenic germs are also considered. For example, the WHO in 1969 considered as natural mineral water microbiologically uncontaminated water from underground sources, with a minimum mineralization of 1 g per kg of water or 250 mg of free CO₂, with favorable properties for health, according to criteria accepted by the FAO/WHO Coordinating Committee (1985).

9. Conclusions

Groundwater, an essential source of freshwater, plays a vital role in the hydrological cycle and in sustaining ecosystems. Despite its importance, access to freshwater is limited, and aquifers are increasingly threatened by the effects of the climate crisis and pollution. In Colombia, a country noted for its water wealth, effective management of these waters is crucial not only for the country’s biodiversity, but also for global water balance.

The physico-chemical characteristics of groundwater, determined by the local geology, include variations in pH, temperature, turbidity, ionic content, and levels of metals and minerals. These waters may contain harmful elements of biogenic, geogenic, and anthropogenic origin, such as high concentrations of salts, heavy metals, and chemical pollutants, which are determining factors in their quality and usability. Historically, emerging mineral waters from aquifers have been valued for their therapeutic potential and used for various purposes, including consumption after purification. However, research on their properties and associated risks is insufficient, especially in regions such as Colombia. Multidisciplinary research and monitoring programs are essential to ensure sustainable and safe management.

In addition, groundwater exploration and management require advanced techniques to identify aquifers and assess water quality. With the increase in groundwater abstraction globally, mainly for agricultural, domestic, and industrial use, the need for effective management and robust legislation that adheres to health and environmental guidelines is highlighted. Quality standards for both drinking and mineral water are essential to ensure its safety and benefits.

The challenges and opportunities related to groundwater in Colombia are diverse and include environmental, social, and economic aspects. One of the main challenges is to control and prevent pollution from industrial, agricultural, mining, and urban activities to ensure water quality and availability for ecosystems and human consumption. Another challenge is to control over-exploitation of aquifers, which reduces water levels and affects long-term availability. It is necessary to ensure the equitable distribution and use of these resources, especially in rural areas and where social conflicts and public order have limited access to water. There is also a need to generate more detailed scientific information on various aspects of groundwater and to establish groundwater management plans. The opportunities are also great, as groundwater can provide a safe and reliable source of water, especially in areas where other sources are scarce or contaminated. As part of the recovery process, it is possible to implement aquifer recharge methods to improve groundwater levels and ensure their long-term sustainability; promoting more efficient agricultural and water use practices that can help reduce vulnerability and improve sustainability, and developing integrated water management approaches that consider both surface and groundwater can be an opportunity to address challenges more effectively. Also, promoting research and technology to better understand groundwater dynamics, address contamination, and improve management practices can lead to innovative solutions.

Finally, climate change, biodiversity loss, pollution, and population growth pose significant challenges to the availability of clean and safe water. The conservation and efficient use of groundwater requires comprehensive management, including scientific research, rigorous monitoring, and robust legal frameworks, to ensure its sustainable and safe use in the future.