Water from the springs of the Himalayas is often marketed as the purest form of drinking water, but how clean is this water? While the sentiment may be dismissed as a marketing ploy, for the communities living around the springs, this is not just a luxury packaged good, but their source of everyday drinking water.
Researchers frpm Banaras Hindu University, Uttar Pradesh, Pennsylvania State University, USA, Western Sydney University, Australia, Bhabha Atomic Research Centre, Mumbai, University of Kara, Togo, Virginia Tech, USA, Anna University, Chennai, Indian Institute of Technology (IIT) Roorkee, have studied the of the Himalays spring water to see how pure they really are. In a new study, the team examined the Khulgad micro-watershed in Kumaun Lesser Himalayas, conducting a detailed analysis of both pre- and post-monsoon periods, giving a clearer picture of seasonal changes and specific factors influencing water quality.
Did You Know? The Himalayas are often called the Third Pole because they hold the most significant amount of ice outside the Arctic and Antarctic. The meltwater from these glaciers, along with rainfall and snowmelt, feeds countless rivers and springs that supply water to billions of people across Asia. |
The Khulgad micro watershed is located in the Kosi basin, Kumaun Lesser Himalayan terrain of India, in the district of Almora, in Uttarakhand. The researchers trekked the rugged Himalayan landscape to collect water samples from 98 different springs in the region. They collected water during two key periods: before the monsoon season (pre-monsoon, or PRM) and after the monsoon season (post-monsoon, or POM). Their goal was to determine the quality of the spring water, understand how its chemical makeup changes, and identify potential factors that could compromise its quality.
The researchers analysed parameters of the water, like its temperature, how much solid stuff was dissolved in it (Total Dissolved Solids or TDS), and the levels of different minerals and chemical ions. They found that about 18.4% of pre-monsoon samples and 15.2% of post-monsoon samples were too acidic for drinking based on Indian and WHO standards. In the pre-monsoon period, 2.6% of samples had fluoride levels exceeding drinking water limits. A more significant concern was nitrate, with about 10.5% of pre-monsoon and 12.1% of post-monsoon samples exceeding the permissible limit. A small percentage (2.6% pre-monsoon, 1.5% post-monsoon) of samples also exceeded potassium limits.
To understand how these chemicals get into the water and what processes are at play, the researchers used Principal Component Analysis (PCA). This statistical method helps find patterns and relationships in complex data. PCA helped them identify that the water's chemistry is influenced by two main things: the natural geology of the area (what kind of rocks the water flows through) and human activities. They also used geochemical mass balance modeling to figure out which minerals are dissolving into the water and how that affects its composition.
The study found that the type of water found in the springs changes as it travels. In higher, more remote areas, the water tends to be a freshwater type, often rich in calcium and bicarbonate (Ca-HCO3). As the water moves down through different rock layers and closer to human settlements, it shows more of calcium-sodium-chloride (Ca-Na-Cl). This evolution is linked to the water interacting with rocks over longer periods and potentially picking up more dissolved substances. The main natural process influencing the water's chemistry was the weathering (dissolving) of silicate minerals in the rocks. Fluoride and potassium were primarily linked to these natural rock sources. Sulfates also partly came from the oxidation of sulfide minerals in the rocks. Ion exchange processes, where water swaps chemicals with the clay in the soil, also played a role. Nitrate contamination, however, was strongly linked to human activities like agricultural runoff (from fertilisers and manure), wastewater seepage, and waste disposal. Chloride and some sulfate were also connected to these surface contaminations.
However, the researchers themselves point out a limitation: they didn't analyse nitrogen and oxygen isotopes. These isotopes are super helpful for pinpointing the exact source of nitrates, for example, whether it's from farm fertiliser or sewage. The study suggests that future research should include these isotopic analyses, along with more detailed monitoring of spring flow and water chemistry, to create an even more accurate model of how the water behaves.
The fact that human activities, particularly agriculture, are impacting the quality of Himalayan spring water is a wake-up call. These springs are not just sources of water; they are often deeply connected to the culture and daily lives of mountain communities. By understanding the pathways of contamination, we can develop better strategies for protecting these vital water sources. This includes promoting sustainable farming practices, improving waste management, and raising community awareness about the importance of safeguarding springs. Ultimately, this research helps us ensure that these life-giving waters remain clean and safe for generations to come, benefiting not only the local communities but also contributing to the broader understanding of water resource management in fragile mountain ecosystems.
This article was written with the help of generative AI and edited by an editor at Research Matters.
The article was edited to add a missing punctuation. The error is regretted.