Nov-Dec 2011: Essay - Let the Genie Out of the Bottle
Cola and cool drink companies try to position themselves as thirst quenchers. No matter what they do however, it is that good old glass of water you reach out to on a thirsty summer afternoon. Small wonder then, that the same companies have bottled water businesses too. Today, in urban India, bottled water is a ubiquitous essential. State-run Volvo buses provide bottled water gratis with a seat, establishments buy them for their staff, and I have seen households, in fact entire apartment complexes, depend entirely on bottled water for all their drinking and cooking purposes. Bottled water has become the symbol of drinking water in our larger cities.
Yet, perhaps 20 years ago when I was in high school my sister and I would race out to fill our bottle with drinking water from public taps on the railway stations during our annual family trip to ‘north India’. In these two decades then, what has changed, that we think we cannot drink water from those same taps? Has the quality of the water coming out of them deteriorated? Has our faith in the institutions that deliver water to the taps eroded? Or has our understanding changed, of what safe drinking water is? Is our bottled-water adoption a result of the insecurity created by this understanding?
Why do we think that bottled water is safe to drink? Any bottle of water should have information on the treatment water is subjected to before it is bottled, e.g., “Our stringent purification processes (including UV treatment, Reverse Osmosis, Microfiltration) as well as multiple quality checks ensure quality of packaged drinking water”.
And what does all this mean: UV treatment, Reverse Osmosis, Microfiltration? What was wrong with the water before this treatment and how does such treatment make it drink-worthy? Let’s try and find answers to these questions.
Firstly, we do understand that not all water is potable. We know that if we drink water that’s not ‘clean enough’ we could be prey to diseases such as jaundice, cholera and gastro-enteritis. So what water is potable? Well, water that meets the standards - the BIS (Bureau of Indian Standards) 10500:1991 Indian Standards for Drinking Water, to be precise (extracted overleaf). Let’s interpret the standards as we talk more.
Getting back to the water before it is treated, how good is our water at source? Well, that depends on the source. If you are among the fortunate urban dwellers who have a municipal water connection, it is likely you are provided piped drinking water supply. How do the municipal authorities ensure the water is of drinking quality? The most accepted way they do this is using surface sources of water (that is water from lakes or rivers) and then treating them for suspended matter (typically through sand filters) and microbial contamination (commonly through chlorination). This allows us to interpret the first part of water quality. Characteristics like colour, odour, taste and turbidity all relate to directly perceivable water quality aspects that our senses can grasp. Measures for taste and odour as you can see are subjective. Colour and Turbidity are measured based on suspended matter in the water – matter that you can see if you hold a glass of water to light. Some of these may actually settle down if you allow the water to stay undisturbed for a long time; indeed as happens in our storage tanks, underground or overhead.
To treat microbial contamination, authorities chlorinate the water, and ensure that there is an availability of what is called ‘Residual, free chlorine’ in water. If this number is 2 parts per million or 2 milligrams / litre of water (both are the same), it means there is enough ‘free chlorine’ in the water, that should there be an entry of new microbial organisms (perhaps in your underground tank), the chlorine will kill the microbial activity. However, too much free chlorine, it has been argued of late, is carcinogenic!
Our most instinctive understanding of clean water refers to microbial activity. We avoid water at the street-side shop because we’re afraid of this form of contamination. Water borne diseases are caused by bacteria, viruses, protozoans and parasites. The most common cause is pathogenic bacteria called ‘Fecal coliform’, a class of bacteria whose source most often is the fecal matter of humans or animals. So the bacterial counts in the standards and free-chlorine help establish if water is free from dangerous microbes. Our household treatment systems, from the simple cloth filter in combination with a rolling boil of water, to filters with chlorine tablets or even the more sophisticated UV filtration primarily deals with these forms of contamination. Strong UV radiation also kills microbial activity. We tend to use this even though our municipal supply supposedly provides drinking water because what guarantee there has been no contamination of the water in the drinking water pipes from source to house? We also store municipal water in tanks where it can get contaminated, therefore household treatment for microbes is a good precaution.
What if you are not connected to municipal supply? Or your municipal supply, like in many small towns of India, is driven from wells or borewells and not rivers or lakes? In either case you are dependent on groundwater. Groundwater is water that has percolated from the surface down through layers of soil and has accumulated in the earth. An open well allows us to extract this water when it is not too deep down. A bore well allows us to extract it when it is available at deeper levels. As water percolates down from the surface into the earth, its quality gets affected. In addition to suspended matter, and microbial activity, we may need to worry about a few more things. Water picks up a variety of minerals and salts from the earth as it percolates down. Unlike suspended matter, we cannot see this matter since it is dissolved, like salt or sugar disappears into water. The standards table deals with a number of measures for such dissolved salts and sets limits on them. ‘Total Dissolved Salts’ or simply ‘Dissolved Salts’ is an aggregate measure of different kinds of dissolved salts. There is a limit on that, and there is a limit on each kind of salt. Excessive fluoride in water for example, causes dental and skeletal Fluorosis. Fluorides occur in groundwater due to natural geological reasons, but also where we have extracted water so much from the ground that the water table has sunk very deep. Karnataka alone has over 5000 villages affected with excessive fluorides in groundwater but with no alternate surface source of water. There are more such villages across the country. High nitrates cause what is called the ‘blue baby syndrome’, a condition in which infants are born with oxygen deprivation problems. In urban areas, high nitrates are increasingly found because sewage leaches nitrates into groundwater. The high use of fertilizers (urea) is another source of high nitrates.
Of late, on television, we have cinema actresses exhorting us to use particular brands of ‘reverse osmosis systems’ in our homes. The use of such systems has arisen out of the increasing use of ground water as a source of water supply. The reverse osmosis system is a very energy intensive way of getting rid of almost all the dissolved salts and microbes at one go. It does so by taking a volume of water and concentrating all the contaminants in one part of it while cleaning the rest. So it generates a waste stream of water that is generally more dangerous for health than the original source, and this waste stream needs to be dealt with. For every litre of clean water we get out of the system, we extract much more from the source.
The other set of contaminants in drinking water that the standards deal with are special kinds of contaminants, like metals, radioactive substances, pesticides or special compounds. They can occur in both surface-water or ground-water sources though they are not very common (except, nowadays, for pesticides). We need to be particularly careful about these if we know that our source is contaminated by an industry, is near a mine, a land-fill, a toxic waste dump or we are in an area of high natural or artificial radioactivity. While many of these kinds of contaminants are not commonly occurring, some of them do occur due to geological reasons. Iron occurs in the groundwater in many places. There are villages in the Gangetic plain and Bangladesh where arsenic in groundwater is common; this is carcinogenic.
Honestly speaking, safe drinking water is a complex science. It is a function not only of water quality but also of our bodies’ immunity. Our forefathers managed well enough without all the science and technology we have access to. It is important to not let all the technology (and its insecurity inducing marketing) take the science out of our lives. A good protocol to follow is to get our regular source of water tested at a local water testing lab at least once a year and to choose our treatment system based on the source quality, not plugging in indiscriminate treatment systems driven through insecurity. And most importantly good science is understanding that what we consume and what we throw away comes back to us through life-giving water – our solid and liquid wastes, our industrial wastes, our fertilisers and pesticides. Good science is understanding and protecting our sources of water personally and as a community; that perhaps, is what our forefathers did better than us.
And as we introspect about our bottle of water, let us also remember that for the vast majority of people in our country the symbol of drinking water, or ‘Meetha paani’, continues to be the lady of the house – the wife, the mother, the cook, carrying a pot of water on her head. And among the more difficult questions for which we haven’t found answers is: how far should she walk from her house to fetch water that is safe for her home and children?