Drinking
water is water that is clean and safe for humans to drink and to use other
domestic purposes such as cooking, washing up, bathing and showering. The
human body is made up of 60-75% water; therefore drinking enough water is
essential to maintain our health. Water helps to relieve or prevent
headaches, constipation and assist in digestion. It further helps
maintaining weight loss (water is calorie free) and keeping the kidneys
healthy. To keep us healthy we should drink at least the minimum of eight
glasses of water per day or 1.5-2.5 litres per day.
Bottled
water in recent times has been very popular to consumers due to the
convenience of being able to it carry around. Tap water is the main source
of drinking water in cities and rural towns. Australian tap water is safe to
drink and Melbourne water is regarded as one of the best drinking water in
the world.
We
can use either bottled water or tap water for drinking, but which water is
healthier? Bottled water is not
subject to rigorous testing and purity standards that is applied to city tap
water (eg. WHO, Australian WQ Guidelines, USEPA). On the other hand, tap
water is regularly tested for common contaminants (eg. microbial pathogens),
inorganic contaminants (eg. arsenic, nitrate, lead) and organic contaminants
(eg. atrazine, pesticides). Chemicals such as fluoride are added in tap
water to prevent tooth decay and chlorine as disinfectant. Research studies
carried out have not found any significant differences in terms of health
benefits between bottled water and tap water, although bottled water is
about 1000 times more expensive than tap water (based on per unit of water).
Nevertheless, bottled water may be an alternative option where tap or
shallow tube well water is contaminated.
Until
recently, Bangladesh rural communities depended on shallow tube wells as a
major source of drinking water. However, due to contamination of these tube
wells with arsenic it has been suggested to use surface water for drinking.
Unfortunately villagers in Bangladesh may still be using ponds and rivers
water for drinking and other purposes. There are potential risks in using
surface water for drinking and other domestic usages as it may possibly be
contaminated with human and animal pathogens and could be a source of water
borne infectious diseases such as cholera. In addition, a recent research
reported that Bangladesh surface water at some places is also contaminated
with toxins producing cyanobacteria (called cyanotoxins). These cyanotoxins
is a potential hazard to public health as it may cause liver damage or even
human death.
A
group of molecular and microbiologists from the U.S.A found that filtering
surface water through an old sari cloth (by folding four to eight times) can
prevent cholera in Bangladesh (see Figure 1). Other scientists further
believe that the same technique (i.e. use of old sari cloth) may also be
useful in filtering out cyanobacteria. Solar Water Disinfection (SODIS)
technique that uses sunlight (UV-A
and increased temperature) can also
be used to treat small quantities of contaminated water. Here contaminated water is filled into transparent
plastic bottles and exposed to full sunlight for at least six hours to
destroy micro organisms that cause water borne diseases.
