Monday, 24 April 2023 | By VP Dimri

GUEST COLUMN

VP Dimri

The Yale University, USA has released a quantitative estimate of the quality of drinking water in all countries. The drinking water is normally termed tap water in the house. There are countries that have 100 per cent pure drinking water and some countries have reasonably good but some countries have a very poor quality of drinking water. The poor quality tap water is being processed through reverse osmosis (RO) to have safe drinking water but one loses basic minerals good for health plus loss of plenty of water in this process. Of course, the best way is to boil the tap water which is safe to drink.

Before I go into detail about water quality in India, I would like to tell you about my experience during stays in Norway and Germany. I went to Germany in 1977 for about 17 months, spending the first five months studying the German language in Dortmund and the remaining 12 months with the Geological Survey of Germany at Hannover. We were told not to take tap water for drinking purposes as Dortmund is an industrial town with many industries in and around Dortmund. After coming to Hannover there were no such instructions. Again in 1986 I along with my family went to Trondheim, Norway for my postdoctoral work at the Norwegian University of Science and Technology (NTNU). My professor at NTNU arranged accommodation for us. After a few days, my professor came to our house to learn about our comforts. It seems he was thirsty and asked for drinking water. I told him that our drinking water which we brought from a shop was finished and we could give him something else like a soft drink. He was surprised to know that our drinking water was over and checked the tap and told us that he wants this tap water which is drinking water. Then I told him that when we were in Dortmund, Germany we were advised not to take tap water for drinking purposes. Then, he took all of us in his car to a lake in the high mountains and told us that the lake is the source of water being supplied to the whole city of Trondheim including our house. It is pure water and today we see that the quality of water in Norway is 100 per cent pure. One can see that the quality of tap water in Germany is not as pure as in Norway and stands at an average of 98.6 per cent. See the table in which the purity of water in some countries is shown.

Drinking water quality in some of the nations studied by Yale University

Now, let us briefly discuss the quality of drinking water in India. The table shows the average values of the quality of water for the whole of India. However, every State may have different values. Some of the States may be better and some may have less pure water. The Himalayan glaciers are the main source of water for the northern part of India. The rivers originating from the Himalaya and flowing on the main lands give plenty of water. The situation is the same for the southern part of India where rivers are the source of water. The rivers in north east India are very pure. These include the Umngot river in Meghalaya, the Teesta river in the Sikkim-West Bengal border, the Brahmaputra river in Assam and the Tuipui river in eastern Mizoram. Among the top five cleanest rivers in India, there is the Chambal river flowing from Rajasthan to Madhya Pradesh. There are some places where groundwater becomes the main source of water. The groundwater gets generated from the northwest monsoon coming from the Arabian sea and the Bay of Bengal towards the mainland after the sea gets heated during summer. Normally the arrival of the monsoon is at the end of May or the first week of June from Kerala towards Goa and Maharashtra and then it turns towards the east passing over Telangana, Andhra Pradesh and meets clouds from the Bay of Bengal while then moving towards the west.  In fact, the whole of India gets monsoon covering south, west, then east and north east and finally turns to the west and north covering Bihar, Uttar Pradesh, Delhi and the Himalaya.  In some places, ground water gets mixed with underground rocks, especially in the south, and gets rich in minerals. Fluoride is such an example in Nalgonda in Telangana and groundwater has more than permissible limits fluoride in groundwater. At other places, we have arsenic in West Bengal and other places. Scientific studies have been carried out extensively to get rid of these unwanted minerals in groundwater for drinking purposes.

The countries which have 100 per cent pure drinking water include Scandinavian countries like Norway, Finland, Iceland and Sweden. In fact, there are some useful points from these examples as the geography of Norway and Uttarakhand are more or less similar. The source of drinking water in Uttarakhand is springs and rivulets, and big rivers depending upon the altitude of the region. For example spring water in high altitude areas is very pure as the source is glaciers-like in Scandinavian nations. The water from the springs can be transferred to the houses through taps.  The water of rivers and rivulets of Uttarakhand within the State’s mountainous area is pure and loses its purity after coming down from the mountains. So, we must use the water of rivers for drinking purposes in low-altitude regions. Villages and towns may be above the level of close by rivers or rivulets. So, the water of these rivers and rivulets can be lifted up by many technical methods such as hydraulic pumps practiced in many countries.  The tap water in Uttarakhand can be as pure as in Scandinavian countries.

However, there are issues with tap water. In some places, it is being supplied without any treatment. The source of such water must be thoroughly studied. Now, there are many scientific studies being carried out in India and abroad. For example, humic acid originates from organic matter for instance from the leaves of plants which may fall on lakes or any source of water then that water is harmful. However, if water has a metal substance then humic acid can be used to clean the waste water. In fact, the treatment of water is a separate matter which is not the subject of this article.  Lastly, tap water or any water may be stored in a clay vessel and/or boiled until the tap water is treated. 

 (A Padma Shri recipient, the author is a scientist who has worked in various institutions. Views expressed are personal)