TDS: A Crucial Factor for Water Health
The water we drink is more than just H₂O; it’s a complex mix of dissolved minerals, salts, and organic matter. It’s important to note that some of these substances originate from human activities, underscoring our responsibility to protect and preserve our water sources. These Total Dissolved Solids (TDS) can significantly influence our health both good and bad ways depending on their concentration in potable water. Understanding TDS and its effect on health is crucial and empowering in ensuring that the water we consume is genuinely safe.
Water is not just H2O; it also contains minerals, salts, and organic matter. These substances can naturally occur or result from human activities. TDS encompasses a variety of dissolved substances, ranging from essential minerals like calcium, sodium, and magnesium to potentially harmful elements like lead and arsenic. The composition of TDS varies depending on the water source and environmental factors, such as springs, wells, rivers, and borewells.
Measurement & Health Guidelines
TDS is measured in parts per million (ppm). The World Health Organisation (WHO) recommends that the TDS level in drinking water should not exceed 1000 ppm for safety and palatability. Water with total dissolved solids levels within this range of 300 to 600 ppm is generally considered suitable for drinking. In comparison, levels above 1000 ppm could pose health risks and affect the taste of water.
TDS and general hardness measure different components within water, such as minerals and salts. Despite examining distinct substances, these two measurements are closely linked; as the concentration of dissolved solids (TDS) rises, the overall hardness of the water tends to increase as well. (Fig.1)
What Contributes to TDS?
India’s diverse geographical and climatic conditions contribute significantly to varying TDS levels. Here are the primary factors:
Geological Factors
- Rock formations – The Indian subcontinent is geologically diverse, with mineral-rich regions contributing to higher TDS levels.
- Soil composition – Soils containing high concentrations of salts and minerals can increase TDS in groundwater.
- Salinity Intrusion – Coastal areas are susceptible to seawater intrusion, increasing TDS in groundwater.
Climatic Factors
- Evaporation – High temperatures in many parts of India lead to increased evaporation, concentrating dissolved solids.
- Rainfall – While rainfall generally dilutes TDS, erratic patterns can influence levels.
Anthropogenic Factors
- Agriculture & Deforestation – Excessive use of fertilisers and pesticides can contaminate water bodies, increasing TDS. Reduced vegetation cover can intensify soil erosion, leading to higher sediment and mineral loads in water bodies.
- Industrialisation – Discharging industrial effluents containing salts and chemicals elevates TDS in rivers and groundwater.
- Urbanisation – Sewage and domestic waste can affect TDS levels in urban water bodies.
- Overexploitation of Groundwater – Over-pumping can lead to increased concentration of dissolved solids in groundwater. India faces severe groundwater depletion in many regions, leading to higher TDS levels.
Balancing the Good and Bad in TDS
Not all dissolved solids are harmful; many are beneficial, too. This balance is crucial and understanding it can reassure you about the safety of your water. Calcium is essential for bone health. Magnesium is necessary for biological functions like blood pressure regulation and muscle health, whereas sodium is vital for bodily functions.
However, the balance of these dissolved compounds is crucial. While some minerals are beneficial, high concentrations of these elements can lead to various problems. For example, excessive calcium and magnesium can cause water hardness, scaling pipes and appliances and reducing their efficiency and lifespan. Right amount of dissolved solids in water contribute to a healthy mineral intake, hydration and improved taste of water. Maintaining the balance of TDS is crucial.
Reverse Osmosis (RO)
RO systems effectively remove many dissolved components, including heavy metals, salts, and organic matter. These systems force water through a
semipermeable membrane that blocks larger molecules and ions, allowing only clean water to pass.
Ion exchange
Ion exchange involves exchanging undesirable ions in water with more desirable ones. For instance, hardness-causing calcium and magnesium ions can be replaced with sodium or hydrogen ions.
Remineralisation
After purification, water can sometimes lack essential minerals. Remineralisation is the process of adding back healthy minerals to improve water’s taste and nutritional value.
Have you heard about the pH factor, which measures the acidity or alkalinity of water? (Fig. 2)
While TDS and pH are distinct parameters, they often influence each other. Certain dissolved solids can impact water’s pH.
Low pH (Acidic Water): Acidic water can dissolve more metals, such as iron and lead. It increases TDS levels and can lead to higher concentrations of harmful metals in the water.
High pH (Alkaline Water): Alkaline water tends to have higher concentrations of bicarbonates and carbonates, contributing to TDS. While not necessarily harmful, it can lead to scaling and other issues.
Fig. 2 pH Scale
Therefore, maintaining the optimal pH level ensures water safety and taste. pH adjusters help to maintain the balance of pH levels in the water.
Can We Modify TDS and pH?
While the modification is complex, technologies are being developed to alter harmful components into harmless or beneficial forms. This approach, though still in its infancy, holds promise for the future of water purification. For instance, specific advanced filtration systems can neutralise contaminants, converting them into non-toxic substances.
Advances in Water Purification Technologies
Emerging technologies in water purification aim to make the process more efficient, sustainable and right amount of TDS in water. Some promising approaches include:
– Electrodialysis process uses electrical potential to move ions through selective membranes, effectively reducing TDS.
– Nanofiltration uses nanometer-sized pores to filter out contaminants while allowing beneficial minerals to pass through.
– Advanced Oxidation Processes (AOPs) use oxidants to break down harmful organic and inorganic substances, reducing TDS and improving water quality.
About NICHEM
Long-standing Specialty Chemicals player with ISO 9001:2015 certification and a history of providing specialty solutions for over 25 years. The company is headed by senior chemical industry specialists with the combined expertise of more than 100 years. With an emphasis on eco-friendly, non-toxic products, the company’s primary strength is research, development, and customisation. More information on NICHEM can be found at https://nichem.solutions.
