TYPES OF WATER IMPURITIES

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CONTAMINATING water can be caused accidentally or unknowingly. But making water safe can never be accidental. It must be intentional and deliberate. Water, especially drinking water must not just be clean but safe. Not all clean water is safe water.

It is quite sad to observe that we are starting the new year with water contamination issue in Lusaka. According to media reports, the contaminated water affected approximately 410 people. After consuming the water, some of them developed vomitting and stomach upset.

Last year, we started the year with the issue of cholera. It’s amazing to note that both issues are linked to poor water safety. Cholera, which started in Lusaka, spread to other parts of the country.

I hope the water contamination which has started in Lusaka will not lead to the discovery that water is contaminated in other parts of the country too.

The water utility companies must do their best to ensure that water supplied to consumers is safe. Investigation for the Lusaka water contamination is underway and we will patiently wait for results.

Currently we don’t know what type of contamination it was and how it got into the water pipe system. The Lusaka water contamination may tempt someone to think that maybe – just maybe – the fear of another cholera outbreak may have forced Lusaka Water and Sewerage Company (LWSC) to overdose chemicals during water treatment! Hence causing chemical contamination. Forgive my imagination. Anyway let’s wait for the results of the investigations.

Today, I would like highlight various types of water impurities which can contaminate water. There are only three types of impurities – physical, chemical and biological impurities.

Water picks up these impurities as it flows on or sinks in the ground. Human activities may also introduce these impurities in the water. Let’s look at each one.

The first ones are physical impurities. These impurities float on or in water. They are suspended in water. These impurities determine the clarity of water. They make water look dirty.

No one wants to drink water which is not clear. This is probably the reason why we don’t have coloured water or flavoured water like most carbonated drinks. Safe drinking water must be colourless, tasteless and odourless. These impurities can easily be detected by our naked eyes.

The second ones are chemical impurities. These impurities are dissolved in water. Just like you can’t see salt after you dissolve it in water, you can’t see dissolved impurities with your naked eyes.

These impurities influence the taste of water. Safe water is expected to be tasteless. No one wants to drink water that has some taste. It is not always that you can detect the presence of chemical impurities in water by tasting. Not all chemical impurities affect the taste of water.

In small quantities, dissolved chemicals are needed in water. I am sure you have seen them on the bottles of mineral water. The presence of chemical impurities like calcium or magnesium makes water “hard” which causes scaling in equipment like geysers, boilers and heat exchangers.

Chemical impurities also pose various health risks to people. Presence of heavy metals in drinking water may cause cancer and damage to the nervous system. Depending on the nature and concentration of chemical contamination, the impact can either be immediate or long-term.

Immediate effects of high chemical contamination differ from chemical to chemical but may include vomiting, dizziness and diarrhoea. The long-term impact of chemical impurities usually occurs slowly over time. Hence most people may not even realise it.

The third and last ones are biological impurities. These are harmful microorganisms which live in water. It is these microorganisms living in water which cause waterborne diseases like cholera, diarrhoea, dysentery or typhoid.

Safe water is expected to be free of any harmful microorganisms. Microorganisms are invisible. You can’t see them with your naked eyes. In fact, you may not detect them by sight, smell or taste. You can’t tell biological contamination simply by the appearance of water.

In my opinion, biological contamination is probably the most serious because its health effects are almost immediate and, in worst cases, fatal.

For instance, if you drink water contaminated with cholera-causing bacteria, within a short time, you will develop cholera which can kill you within a matter of hours if left untreated. Besides from one cholera patient, the cholera disease can spread fast and affect the entire community. This explains why biological treatment is so critical.

Safe water must be free from all the three types of impurities. The water utility companies have the responsibility of ensuring that drinking water is safe for consumers.

The need to make water safe cannot be over emphasised. Even at domestic level, we need to ensure that drinking water is safe by adding chlorine or boiling.

Even borehole water must be treated. Since borehole water is usually clear, it’s tempting to feel that it is safe. Don’t just drink water, drink safe water. Until next week, stay safe. Zambia needs you.

*The author is the CEO of SafetyFocus, a safety company committed to providing safety training and consultancy.

For your comments, contact the author on cell +260 975 255770 or email: marksucceed@gmail.com

Mark Kunda – Safety Consultant.

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