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Saline water
Saline water
Saline water
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Water salinity
Salinity levels
Fresh water (< 0.05%)
Brackish water (0.05–3%)
Saline water (3–5%)
Brine (> 5% up to 26%–28% max)
Bodies of water

Saline water (more commonly known as salt water) is water that contains a high concentration of dissolved salts (mainly sodium chloride). On the United States Geological Survey (USGS) salinity scale, saline water is saltier than brackish water, but less salty than brine. The salt concentration is usually expressed in parts per thousand (permille, ‰) and parts per million (ppm). The USGS salinity scale defines three levels of saline water. The salt concentration in slightly saline water is 1,000 to 3,000 ppm (0.1–0.3%); in moderately saline water is 3,000 to 10,000 ppm (0.3–1%); and in highly saline water is 10,000 to 35,000 ppm (1–3.5%). Seawater has a salinity of roughly 35,000 ppm, equivalent to 35 grams of salt per one liter (or kilogram) of water. The saturation level is only nominally dependent on the temperature of the water.[1] At 20 °C (68 °F) one liter of water can dissolve about 357 grams of salt, a concentration of 26.3 percent by weight (% w/w). At 100 °C (212 °F) (the boiling temperature of pure water), the amount of salt that can be dissolved in one liter of water increases to about 391 grams, a concentration of 28.1% w/w.

Properties

[edit]
Water-NaCl phase diagram
Properties of water-NaCl mixtures[2]
NaCl, wt% Freezing point (°C) Freezing point (°F) Density[a] (g/cm3) Refractive index[b] at 589 nm Viscosity[c] (cP )
0 0 32 0.99984 1.3330 1.002
0.5 −0.3 31.46 1.0018 1.3339 1.011
1 −0.59 30.94 1.0053 1.3347 1.02
2 −1.19 29.86 1.0125 1.3365 1.036
3 −1.79 28.78 1.0196 1.3383 1.052
4 −2.41 27.66 1.0268 1.3400 1.068
5 −3.05 26.51 1.0340 1.3418 1.085
6 −3.7 25.34 1.0413 1.3435 1.104
7 −4.38 24.12 1.0486 1.3453 1.124
8 −5.08 22.86 1.0559 1.3470 1.145
9 −5.81 21.54 1.0633 1.3488 1.168
10 −6.56 20.19 1.0707 1.3505 1.193
12 −8.18 17.28 1.0857 1.3541 1.25
14 −9.94 14.11 1.1008 1.3576 1.317
16 −11.89 10.60 1.1162 1.3612 1.388
18 −14.04 6.73 1.1319 1.3648 1.463
20 −16.46 2.37 1.1478 1.3684 1.557
[d]23.3 −21.1 −5.98 1.179
26 −19.18 −2.52 1.193 1.3795 1.676
  1. ^ At some ambient temperature
  2. ^ At some ambient temperature
  3. ^ At some ambient temperature (20°C)
  4. ^ Eutectic mixture

At 100 °C (212 °F; 373 K), saturated sodium chloride brine is about 28% salt by weight. At 0 °C (32 °F; 273 K), brine can only hold about 26% salt.[3] At 20 °C one liter of water can dissolve about 357 grams of salt, a concentration of 26.3%.[4]

The thermal conductivity of seawater (3.5% dissolved salt by weight) is 0.6 W/mK at 25 °C (77 °F).[5] The thermal conductivity decreases with increasing salinity and increases with increasing temperature. [6] [7] The salt content can be determined with a salinometer.

Density ρ of brine at various concentrations and temperatures from 200 to 575 °C (392 to 1,067 °F) can be approximated with a linear equation:[8]

where the values of an are:

Weight % a2 a3
5 0.043 72.60
10 0.039 73.72
15 0.035 74.86
20 0.032 76.21
25 0.030 77.85

Electrolysis

[edit]

About four percent of hydrogen gas produced worldwide is created by electrolysis. The majority of this hydrogen produced through electrolysis is a side product in the production of chlorine.

  • 2 NaCl(aq) + 2 H2O(l) → 2 NaOH(aq) + H2(g) + Cl2(g)

See also

[edit]

References

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Saline water

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from Grokipedia
Saline water is water that contains significant concentrations of dissolved salts, most commonly , with levels typically measured in parts per million (ppm) or milligrams per liter (mg/L) of . According to classifications by the U.S. Geological Survey (USGS), saline water encompasses slightly saline water (1,000–3,000 ppm TDS), moderately saline water (3,000–10,000 ppm TDS), and highly saline water (greater than 10,000 ppm TDS), in contrast to , which has less than 1,000 ppm TDS; for comparison, average is approximately 35,000 ppm TDS. Saline water occurs naturally in vast quantities worldwide, primarily in oceans and seas, which cover about 71% of Earth's surface, as well as in saline aquifers that underlie much of the continents. , saline resources underlie much of the country, with major occurrences in coastal plains, sedimentary basins, and arid regions where concentrates salts. Human activities, including agricultural , industrial effluents, discharges, and the application of road salts for de-icing, contribute to secondary salinization of rivers, lakes, and aquifers, amplifying natural sources and leading to freshwater salinization in many areas. While saline water is unsuitable for most , , or uses due to its potential to harm , animals, and through and , it serves critical roles in industrial applications. , the primary use is for cooling in thermoelectric power plants, accounting for about 39 billion gallons per day of saline water in 2015; other applications include and gas extraction, , and limited livestock in water-scarce regions. However, rising salinization from , sea-level rise, and land-use practices threatens ecosystems by altering , increasing heavy metal mobilization, and degrading for beneficial uses.

Definition and Classification

Salinity Scales

Salinity is defined as the total concentration of dissolved salts in water, predominantly along with other ions such as , calcium, and , expressed in units of grams of salt per of solution (g/kg) or parts per thousand (‰ or ppt). In , practical salinity units (PSU) are used, where 1 PSU is approximately equivalent to 1 g/kg of dissolved salts for typical compositions. This measure provides a standardized way to quantify the salt content, which influences water , , and biological processes. Historically, salinity was measured using the chlorinity scale, which determined the concentration of ions (primarily ) through with . Chlorinity (Cl) was defined as the grams of silver required to precipitate the from 0.3285234 kg of , and salinity was approximated by the relation S (‰) = 1.80655 × Cl (‰). This method, developed in the late by and refined through international standards, was widely used until the mid-20th century but was limited by its focus on rather than total salts and by inaccuracies. Another common scale is total dissolved solids (TDS), which measures the mass of all inorganic and organic substances remaining after evaporating a sample, typically reported in milligrams per liter (mg/L). For freshwater and low-salinity environments, salinity in ppt approximates TDS in mg/L divided by 1,000, providing a direct mass-based estimate. The modern standard, the UNESCO Practical Salinity Scale 1978 (PSS-78), replaced earlier scales by defining practical salinity (S) as a unitless approximately equal to the of dissolved salts in grams per kilogram of , calculated primarily from electrical conductivity measurements. PSS-78 is based on the conductivity ratio Rt=C(S,t,p)C(35,t,p)R_t = \frac{C(S, t, p)}{C(35, t, p)}, where C(S,t,p)C(S, t, p) is the conductivity of the sample at salinity S, t (°C on the International Practical Temperature Scale-68), and p (decibars), and C(35,t,p)C(35, t, p) is the conductivity of standard with S = 35 at the same t and p. To compute S, the measured conductivity is first corrected to the ratio at 15°C and (R_{15}) using the temperature dependence function defined in PSS-78, which involves a rational rather than a simple ; detailed coefficients are provided in (1983). Then, S is derived from R_{15} via the : S=a0+a1R150.5+a2R15+a3R151.5+a4R152+a5R152.5S = a_0 + a_1 R_{15}^{0.5} + a_2 R_{15} + a_3 R_{15}^{1.5} + a_4 R_{15}^2 + a_5 R_{15}^{2.5} where the coefficients are a_0 = 0.0080, a_1 = -0.1692, a_2 = 25.3851, a_3 = 14.0941, a_4 = -7.0261, and a_5 = 2.7081. A pressure correction term ΔS is added to account for the increase in conductivity under hydrostatic pressure. The full ΔS is given by a polynomial in p, S, and t: ΔS = p (b_0 + b_1 S + b_2 S^2 + b_3 t + ...) up to higher orders, with coefficients specified in UNESCO (1983); a rough approximation is ΔS ≈ 0.00025 p for typical conditions (p in dbar). For seawater, practical salinity in PSU approximates TDS in g/kg, with average open-ocean values around 35 PSU corresponding to roughly 35 g/kg TDS. Measurement accuracy in PSS-78 relies on correcting for environmental factors, as conductivity varies nonlinearly with (increasing by approximately 2% per °C) and (increasing by about 1.3% per 100 dbar at 25°C). Instruments like conductivity-temperature-depth (CTD) profilers apply these real-time corrections using the PSS-78 algorithms to achieve precisions of 0.002–0.005 PSU. Deviations can arise from non-standard ionic compositions, such as in brackish or polluted waters, where conductivity-based may slightly overestimate or underestimate true mass-based salinity by up to 1–2%.

Types of Saline Water

Saline water is categorized based on its total dissolved solids content, primarily measured in parts per thousand (ppt); note that classifications can vary by context, such as oceanography versus water resources management. According to U.S. Geological Survey (USGS) standards, fresh water has less than 1 ppt (1,000 ppm TDS), while saline water encompasses slightly saline (1–3 ppt), moderately saline (3–10 ppt), and highly saline water (greater than 10 ppt). In oceanographic contexts, brackish water typically falls between 0.5 and ~10–30 ppt, occurring in transitional zones like estuaries where fresh and saline waters mix. Seawater, a type of saline water, has an average salinity of approximately 35 ppt (range typically 32–37 ppt in open oceans), while brine exceeds ~40–50 ppt and is characterized by its extreme salt concentration that limits biological activity. Within these categories, hypersaline waters represent a subtype of brine with salinities far exceeding that of , often surpassing 100 ppt and approaching saturation levels. For instance, the Dead Sea maintains a hypersaline composition of approximately 340 ppt, dominated by magnesium and calcium salts due to extensive . Saline waters are further distinguished by their origins as either natural or anthropogenic. Natural saline waters form through geological and hydrological processes in marine and inland environments, whereas anthropogenic saline waters arise from human activities, such as desalination plant effluents or industrial brines from and oil production, which can introduce elevated salt levels into local water systems. Beyond total salinity, classification considers variations in ionic composition, which influence water chemistry and usability. Seawater is predominantly chloride-dominated, with comprising the majority of dissolved ions, whereas some inland or saline sources exhibit sulfate dominance, often due to mineral dissolution from sulfate-rich rocks like .

Physical and Chemical Properties

Physical Characteristics

Saline water's is greater than that of owing to the contributed by dissolved salts without a proportional increase in . For typical with a of 35 ppt at 25°C and , the is approximately 1.025 g/cm³, whereas at the same conditions has a of about 0.997 g/cm³. This difference arises from the saline contraction effect, where the addition of salts causes a slight reduction. The relationship can be approximated linearly as ρ=ρfresh+βS,\rho = \rho_{\text{fresh}} + \beta S, where ρ\rho is the density of saline water, ρfresh\rho_{\text{fresh}} is the density of fresh water, SS is salinity in parts per thousand (ppt), and β\beta is the haline contraction coefficient, valued at roughly 0.8×10−30.8 \times 10^{-3} (in units consistent with density in g/cm³ and SS in ppt). The freezing point of saline water is depressed relative to pure water due to colligative properties, which depend on the number of solute particles disrupting the formation of ice crystals. Seawater with 35 ppt salinity freezes at approximately -1.8°C under standard conditions, compared to 0°C for fresh water. This depression follows from the lowered vapor pressure of the solution, making it energetically favorable for the liquid phase to persist at lower temperatures. Salinity also elevates the through similar colligative mechanisms, requiring higher temperatures to achieve the needed for boiling. For at 35 ppt, the is about 0.5°C at 1 , yielding an effective of roughly 100.5°C. Additionally, dissolved salts increase the of by enhancing intermolecular interactions, with 's dynamic at 20°C being approximately 1.05 mPa·s, or about 5% higher than that of (0.998 mPa·s). Optically, saline water's refractive index rises with increasing salt content, altering propagation. Seawater at 20°C and 35 ppt has a refractive index of about 1.340 for sodium D-line (589 nm), compared to 1.333 for pure water, due to the higher of the ionic solution. In high- environments, such as brines exceeding 100 ppt, transparency can be reduced through modest increases in from clusters, though particulate matter often plays a larger role in overall clarity.

Chemical Composition and Reactions

Saline water, particularly , is dominated by , with ions (Cl⁻) comprising approximately 55% of the total ionic content by mass and sodium ions (Na⁺) accounting for about 30.6%. Other major ions include magnesium (Mg²⁺) at 3.7%, (SO₄²⁻) at 7.7%, calcium (Ca²⁺) at 1.2%, and (K⁺) at 1.1%, contributing to the overall typically around 35 g/kg. In standard , concentration is roughly 19.4 g/kg, while sodium is about 10.8 g/kg, with these proportions remaining relatively constant across oceanic samples due to conservative mixing behavior. The of saline water generally ranges from 7.5 to 8.4, maintained by buffering systems involving (HCO₃⁻) and (B(OH)₄⁻) ions, which resist acidification from dissolved CO₂. The carbonate- equilibrium predominates, where CO₂ reacts to form , which dissociates into bicarbonate and hydrogen ions, stabilizing around 8.1–8.3 in surface . contributes additional buffering capacity, particularly at higher values, enhancing the system's resistance to perturbations. Electrolysis of saline water, such as solutions, yields distinct products due to the ionic composition: gas (Cl₂) evolves at the , gas (H₂) at the , and (NaOH) in the . The overall reaction is: 2NaCl+2H2O→Cl2+H2+2NaOH2\text{NaCl} + 2\text{H}_2\text{O} \rightarrow \text{Cl}_2 + \text{H}_2 + 2\text{NaOH} This process underpins the industrial chlor-alkali production, generating essential chemicals like caustic soda and for manufacturing. Chloride ions in saline water significantly accelerate of metals, particularly through pitting and crevice mechanisms that disrupt protective layers on surfaces like and . High chloride concentrations promote localized anodic dissolution, leading to rapid pit formation and structural weakening in marine environments. This effect is exacerbated in saline solutions, where Cl⁻ ions penetrate passive films, initiating autocatalytic processes.

Natural Sources

Oceanic Sources

Oceans constitute the primary reservoir of saline water on , holding approximately 97% of the planet's total volume. This vast expanse encompasses about 1.335 billion cubic kilometers of , with an average of 35 parts per thousand (ppt). The of oceanic arises from a balance of processes that concentrate dissolved salts, primarily through exceeding in subtropical gyre regions, where high solar radiation drives loss and leaves salts behind. In contrast, coastal areas experience dilution from freshwater river inflows, reducing local . further maintains gradients by transporting denser, saltier to deeper layers and mixing it with less saline surface waters, ensuring a dynamic equilibrium across basins. Salinity varies regionally due to these processes and local conditions; for instance, the exhibits higher values around 41 ppt owing to intense in its semi-enclosed basin with limited freshwater input. Polar regions, conversely, show lower salinities, often below 34 ppt, primarily from seasonal ice melt introducing freshwater. Over geological timescales, ocean salinity has remained relatively stable at near-modern levels for billions of years, modulated by through the formation and subduction of ocean basins, which regulate salt inputs from continental and outputs via .

Inland and Subsurface Sources

Inland saline waters occur primarily in endorheic basins where and inflow are insufficient to counterbalance high rates, leading to the concentration of dissolved salts from and atmospheric inputs. These environments are prevalent in arid and semi-arid regions, resulting in hypersaline lakes that can exceed ocean levels by several times. For instance, the Dead Sea in the maintains a of approximately 340 g/L, primarily composed of magnesium, sodium, calcium, and potassium chlorides, due to its isolation and extreme under a hot, dry climate. Similarly, the in , , exhibits variable ranging from 50 to 270 ppt, fluctuating with water levels influenced by river inflows and evaporative losses; during low-water periods, the south arm can reach up to 270 ppt, while the north arm often exceeds 300 ppt in isolated brine layers. Subsurface sources of saline water include aquifers and brine wells that tap into highly concentrated fluids trapped in sedimentary formations. These brines often originate from ancient marine incursions, where was evaporated and preserved in porous rock layers over geological timescales. In the Permian Basin of and , for example, produced brines from oil and gas wells exhibit salinities exceeding 200 ppt, with up to 270,000 mg/L, reflecting the dissolution of minerals from Permian-age marine deposits. Such subsurface reservoirs are accessed via brine wells for industrial extraction, but their high salinity limits direct use without treatment. The geological origins of these inland and subsurface saline waters trace back to evaporite sequences formed during episodes of restricted marine basins in the geological past. In such settings, repeated transgressions of into enclosed depressions led to sequential precipitation of minerals like , , and as concentrated the brines beyond saturation points. A prominent example is the Zechstein Basin in , where Late Permian evaporites, spanning up to 2,000 meters thick, were deposited across a vast area of over 1,000,000 km² following marine flooding of the region; these deposits now serve as both sources of subsurface brines and impermeable seals in hydrocarbon systems. Similar evaporite formations worldwide, such as those in the Permian Basin, underpin many modern saline aquifers by providing the mineral matrix that dissolves to yield brines. Globally, inland saline bodies, including lakes and subsurface reservoirs, constitute approximately 0.008% of the total water volume on , a figure slightly less than that of freshwater inland waters at 0.009%, though they represent about 44% of all lake surfaces by area. Regional hotspots include the arid interior of , home to numerous ephemeral hypersaline lakes like , and the , where terminal basins such as the Dead Sea and concentrate salts in permanent hypersaline features. These concentrations highlight the role of climatic aridity and tectonic isolation in amplifying saline water accumulation on continents.

Human Applications

Water Supply and Desalination

Saline water, particularly , plays a critical role in addressing global by serving as the primary feedstock for to produce potable water. As of 2023, the worldwide desalination industry produces approximately 100 million cubic meters of per day, meeting a significant portion of needs in water-stressed regions. Roughly 60% of this capacity processes seawater, which typically has salinity levels around 35,000 parts per million, while about 62% of desalinated output is allocated for municipal and drinking water supplies. The development of large-scale began in the , with the construction of the first major plants in arid coastal areas to combat chronic shortages. This saw rapid expansion in regions like the , where now holds about 22% of global desalination capacity, driven by necessity in hyper-arid environments lacking alternative freshwater sources. Over decades, advancements in efficiency and cost have propelled desalination from experimental setups to a cornerstone of , with installed capacity growing at an average annual rate of around 7% since the early . The predominant desalination methods for converting saline water to potable supplies are membrane-based (RO) and thermal-based processes such as multi-stage flash (MSF) . employs semi-permeable membranes that allow water molecules to pass under high pressure while rejecting salts and impurities, achieving energy efficiencies of approximately 3 kWh per cubic meter in modern plants equipped with devices. In contrast, multi-stage flash heats saline water to produce steam that condenses into across successive low-pressure stages, often integrated with power generation for benefits, though it requires higher inputs typically exceeding 10 kWh per cubic meter equivalent. RO now dominates new installations due to its lower energy demands and scalability, accounting for over 60% of global capacity. Key processes in desalination plants include pre-treatment to mitigate and scaling on membranes or heat exchangers, post-treatment to ensure suitability for consumption, and management of concentrated byproduct. Pre-treatment typically involves , , or chemical dosing with antiscalants and biocides to remove particulates, organics, and microorganisms from feedwater, preventing operational declines and extending equipment life. Post-treatment remineralizes the low-mineral desalinated by adding calcium, magnesium, and other ions to achieve balanced and prevent in distribution systems, while also adjusting taste and stability for human use. Brine disposal presents significant challenges, as the hypersaline —often 1.5 to 2 times more concentrated than —can harm marine ecosystems if discharged directly, leading to hypoxia, , and altered ocean chemistry; mitigation strategies include deep-sea outfalls, evaporation ponds, or zero-liquid discharge technologies to minimize environmental impact.

Industrial and Agricultural Uses

Saline water serves as a vital in various , particularly where freshwater scarcity necessitates alternatives. In power generation, is extensively utilized for cooling in coastal thermal power plants, thereby conserving freshwater resources and reducing overall water demand. This approach is common in once-through cooling systems, where saline water is drawn from the , circulated to absorb heat, and discharged back, minimizing freshwater usage in regions with limited supplies. In the oil and gas sector, brines—concentrated saline solutions—are injected into reservoirs to enhance recovery through mechanisms such as wettability alteration and interfacial tension reduction. Low-salinity brines, often tuned with ions like and magnesium, improve sweep and displace residual , increasing recovery rates by up to 10-20% in formations compared to conventional flooding. Chemical production also relies on saline water, notably through the extraction of salt from hypersaline lakes via solar evaporation ponds, which concentrate brines to yield for industrial applications like manufacturing and de-icing. In arid regions, such as the or Australian salars, this method produces millions of tons annually without input, leveraging natural to separate crystals. Agriculturally, (typically 5-30 ppt salinity) supports , especially in coastal ponds where salinity levels of 15-25 ppt optimize growth and survival of species like Penaeus vannamei. These systems mimic estuarine conditions, allowing high-density stocking and yields exceeding 10 tons per in managed brackish environments. For crop irrigation in saline-prone areas, salt-tolerant varieties such as , , and date palms are cultivated using drip systems to deliver controlled amounts of moderately saline water (up to 7-10 dS/m) directly to , minimizing and salt accumulation on surfaces. This precision method enhances leaching in the root zone, sustaining yields in arid zones like California's or Israel's Desert. Globally, approximately 33% of thermal power plant capacity near coastlines employs for cooling, underscoring the scale of saline water's role in industrial operations and highlighting its contribution to . However, poses significant challenges, as marine organisms like and accumulate in pipes and heat exchangers, reducing efficiency by up to 50% and necessitating frequent or chemical treatments. Innovations in zero-liquid discharge (ZLD) systems address management by recycling hypersaline effluents from or , enabling recovery such as from salars in South America's . These integrated processes use and to concentrate brines, extracting battery-grade while eliminating liquid waste, as demonstrated in pilot operations achieving over 90% recovery.

Environmental and Health Considerations

Ecological Impacts

Saline water intrusion and use in irrigation contribute to soil salinization, a process where soluble salts in the soil are transported upward via capillary rise from shallow groundwater and then concentrated on the surface through evaporation, particularly in arid and semi-arid regions with inadequate drainage. Globally, about 10% of irrigated cropland is affected by soil salinity, primarily due to irrigation practices with brackish or saline sources, leading to yield losses that can reach up to 70% for salt-sensitive crops like rice and beans in severely impacted areas, according to the 2024 FAO Global Status of Salt-Affected Soils assessment. This degradation not only hampers plant growth by osmotic stress and ion toxicity but also diminishes soil structure and microbial activity, exacerbating long-term land productivity decline. In aquatic ecosystems, elevated salinity from upstream irrigation return flows and saline groundwater seepage induces hypersalinity stress, disrupting freshwater communities and causing widespread . For instance, in Australia's Murray-Darling Basin, prolonged high periods have harmed native , macroinvertebrates, and riparian vegetation, favoring the dominance of halotolerant species such as certain and tolerant while eliminating salt-sensitive taxa like freshwater snails and amphibians. This shift alters food webs, reduces overall ecosystem resilience, and impairs nutrient cycling, with studies showing up to 50% declines in sensitive macroinvertebrate diversity at levels exceeding 1,000 mg/L. Coastal ecosystems face intensified saline intrusion due to sea-level rise, which pushes saltwater further into estuaries and adjacent , fundamentally altering suitability for freshwater and brackish . In and systems, this intrusion increases soil and water beyond tolerance thresholds for many plants, leading to dieback of freshwater-dependent vegetation and conversion to salt-tolerant in some areas, though overall and loss of occur as tidal flooding expands. Such changes disrupt migratory populations, fish nurseries, and functions, with projections indicating potential loss of up to 30% of global coastal area by 2100 under moderate sea-level rise scenarios. Mitigation strategies have proven effective in curbing these impacts, as demonstrated by Australia's Murray-Darling Basin Salinity Management Program, initiated in the early 2000s, which integrates engineering works like salt interception schemes, improved efficiency, and environmental flow releases to reduce river salinity. This program has achieved approximately 30-50% reductions in salinity at key monitoring sites since 2000, restoring ecological conditions and preventing further decline through targeted investments exceeding AUD 1 billion.

Health Effects and Treatment

Consumption of saline water, defined as water with (TDS) exceeding 1 g/L, poses significant health risks primarily through osmotic imbalance, leading to and increased . High salinity prompts the kidneys to excrete excess sodium, drawing water from body tissues and exacerbating fluid loss, particularly in hot climates where sweat amplifies . The (WHO) does not establish a health-based guideline for TDS but notes that levels above 600 mg/L (0.6 g/L) may cause operational issues and palatability concerns, while exceeding 1,000 mg/L is generally unacceptable for due to potential health implications. Acute ingestion of (TDS 1,000–10,000 mg/L) can cause gastrointestinal distress, including , , and , as the high salt concentration disrupts balance and irritates the digestive tract. Chronic exposure to moderately saline sources contributes to strain through hyperfiltration, where the kidneys work harder to filter excess salts, potentially leading to long-term renal damage and elevated . Studies in coastal regions indicate that regular intake of water with TDS above 500 mg/L correlates with . Vulnerable populations, such as communities in arid coastal areas of , face heightened risks from saline intrusion due to reliance on . Research in these regions shows a 17–42% higher risk of among residents consuming saline water compared to those using freshwater sources, attributed to cumulative sodium loading and limited access to alternatives. Pregnant women in such areas are particularly susceptible, with elevated linked to and risks. Treatment of saline water for safe consumption focuses on salt removal, as boiling only concentrates salts and is ineffective. Home-based methods include filtration, which reduces TDS by 90–99% by forcing water through semi-permeable membranes, and , which evaporates and condenses pure . filters improve taste and odor but do not significantly lower salinity levels. For broader access, communities often rely on desalinated outputs from municipal , though home systems remain essential in remote areas.

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