Every Indian citizen has a right to get safe drinking water. It is one of the Sustainable Development Goals (SDGs) that every country in the world should achieve before 2030.
Therefore, the BIS (Bureau of Indian Standards) has stipulated specific safe drinking water guidelines. We shall go through the guidelines later on in this article. Before that, let us stare at some hard facts.
It is an alarming figure. With this background, let us look at the look at the aspects affecting water quality before discussing the BIS safe drinking water guidelines.
In its purest state, water is a tasteless, colourless, and odourless liquid. However, water has the reputation of being one of the best naturally occurring solvents in the planet.
As any substance will dissolve in water to some extent, it is not easy to find water in its pure state. It contains various impurities such as gases, solids, and so on. As water percolates into the earth, it dissolves the minerals present in it.
We have seen above that there are more than 60 lakh water sources in India. The surface water comprises of rivers, streams, ponds, lakes, and reservoirs. You have wells, springs, mines, and tube wells as sources of groundwater.
Groundwater comprises of dissolved minerals such as calcium, magnesium, sodium, and so on. These dissolved minerals are in the form of carbonates, nitrates, and other salts. You also refer to them as Totally Dissolved Salts (TDS).
At the same time, you have heavy metals like arsenic, lead, cadmium, mercury, and others contaminating water. Many areas in India contain fluorides as well. Also, you have organic impurities like residual animal and vegetable matter.
Surface water contains these organic impurities, human waste, and industrial waste. Groundwater is relatively free from such contaminants because of the strata of the soil act as natural filters.
Now, we know that pure water does not have any taste. Water needs to have some TDS in it to be palatable. The BIS has stipulated specifications for the acceptable and permissible levels of TDS. We shall look into these aspects as well.
We reproduce below the BIS 10500-2012 standard that applies to the purity levels acceptable for human consumption.
|Parameter||Desirable Limit||Permissible Limit||Risks or Effects||Sources of Impurity||Treatment|
|Colour||5 Hz||25 Hz||Visible tint results in decrease in acceptance||Iron, Copper, Manganese, Tannins, Natural Deposits||Filtration, Distillation, Ozonisation, Reverse Osmosis|
|Odour||Agreeable||Agreeable||Rotten Eggs, Musty, Chemical||Chlorine, Hydrogen sulphide, Organic matter, Sewage contamination, Methane Gas||Activated Carbon, Oxidation, Filtration, Air stripping|
|pH||6.5 to 8.5||No Relaxation||Low pH – Metallic taste|
High pH – Bitter taste
|Natural||Increase pH by adding soda ash|
Decrease pH by adding vinegar or citric acid
|TDS||500||2000||Hardness, Scaly deposits, sediments, cloudy coloured water, salty taste, corrosion of pipes||Sewage, animal waste, landfills, nature of the soil, Dissolved minerals, iron, manganese||Reverse Osmosis, Distillation, Ion Exchange|
|Hardness||300||600||Scaling in utensils and hot water systems, soap scums||Dissolved calcium and magnesium from the soil, minerals containing limestone||Water softener Ion Exchange, Reverse Osmosis|
|Alkalinity||200||600||Low alkalinity causes deterioration of plumbing, increase chances of presence of heavy metals||Pipes, landfills,||Neutralizing agent|
|Iron||0.3 mg/l||1.0 mg/l||Brackish Colour, Rusty sediment, bitter taste, brown stains, discoloured beverages||Leaching of cast iron pipes, Natural||Oxidizing filter, Green-sand Mechanical filter|
|Manganese||0.1 mg/l||0.3 mg/l||Brownish colour, black stains on clothes, bitter taste||Landfills, deposits in rocks and soil||Ion Exchange, Chlorination, Oxidizing filter, Green-sand Mechanical filter|
|Sulphate||200 mg/l||400||Bitter, medicinal taste, scaly deposits, rotten-egg odour, laxative effects||Human and animal sewage, a by-product of coal mining industry, industrial waste, Natural deposits||Ion Exchange, distillation, Reverse Osmosis|
|Nitrate||45 mg/l||No Relaxation||Blue baby disease in infants||Livestock, septic systems, manure lagoons, fertilisers, household waste||Ion Exchange, Distillation, Reverse Osmosis|
|Chloride||250 mg/l||1000 mg/l||High blood pressure, salty taste, corrosion in pipes, blackening of stainless steel||Fertilisers, industrial wastes, minerals, sea water||Distillation. Activated Carbon, Reverse Osmosis|
|Fluoride||1.0 mg/l||1.5 mg/l||Brownish discolouration of teeth, bone damage||Industrial waste, Geological||Activated Alumina, Distillation, Reverse Osmosis, Ion Exchange|
|Arsenic||0.01 mg/l||0.05 mg/l||Loss of weight, depression, lack of energy, Carcinogen agent||Pesticides, improper waste disposal, glass industry, semiconductor industry, mining||Activated Alumina filtration, Reverse Osmosis, Distillation, Chemical precipitation, Ion Exchange|
|Chromium||0.05 mg/l||No Relaxation||Skin irritation, skin and nasal ulcers, lung tumours, gastrointestinal effects, nervous and circulatory system damage, accumulation in spleen, bones, kidneys, and liver||Septic systems, Industrial waste, mining, Geological||Ion Exchange, Reverse Osmosis, Distillation|
|Copper||0.05 mg/l||1.5 mg/l||Anaemia, Digestive problems, liver and kidney damage, Gastrointestinal irritations, bitter taste, Blue-green stains||Leaching from copper water pipes, algae treatment, Industrial and mining waste, wood preservatives, Natural deposits||Ion Exchange, Reverse Osmosis, Distillation|
|Cyanide||0.05 mg/l||No Relaxation||Thyroid, nervous system damage||Fertiliser, electronics and steel industry, Plastics mining||Ion Exchange, Reverse Osmosis, Chlorination|
|Lead||0.01 mg/l||No Relaxation||Mental retardation, interference in kidney and neurological functions, hearing loss, blood disorders, hypertension, death at high levels||Paints, diesel combustion, pipes and solder, discarded batteries, leaded gasoline, Natural deposits||Ion Exchange, Activated Carbon, Reverse Osmosis, Distillation|
|Mercury||0.001 mg/l||No Relaxation||Loss of vision and hearing, deterioration of intellect, kidney and nervous system disorders, death at high levels||Fungicides, batteries, mining, electrical equipment, plant, paper, and vinyl chloride, Natural deposits||Reverse Osmosis, Distillation|
|Zinc||5 mg/l||15 mg/l||Metallic taste||Leaching of galvanized pipes, paints, dyes, Natural deposits|
|Total Coliform Bacteria|
|not detectable in any 100 ml sample||15 mg/l||Gastrointestinal illness||Livestock, septic systems, household wastes, manure||Chlorination, Ultraviolet, Distillation, Iodination|
Solutions to the problem
If you go through the above table, you will understand the need for installing high-quality water purifiers. It can help eliminate these contaminants and ensure pure and safe drinking water for all. Some of the best water purification technologies are Reverse Osmosis, Ion Exchange, and Ultraviolet water purification.
The municipalities and other governmental organisations can take the initiative and see to it that it supplies RO purified water to the residents of the cities and villages.
Every household has a responsibility to ensure pure and safe water. A little care can go a long way in solving the problem. India has to go a long way in this regard if they have to achieve the Sustainable Development Goals by 2030.