Water is essential for human survival. Water is considered the most important factor for life on Earth. The human body is made of 70% water, much of which is lost when we pee or sweat. This is why we need to be hydrated at all times. Water carries out many important jobs such as flushing bacteria out of your bladder, aiding digestion, and carrying nutrients and oxygen to the cells.

Water Quality

Clean water is free from microbial, chemical, and

physical contamination. This includes disease-causing

bacteria and toxic metals, and those that have no

health risk, but can make the water unpleasant to

drink (too much iron).

Water quality can be divided into three things:

Microbial contamination is about water with disease-

causing microbes. This is when water comes into

contact with faecal material. These microbes can

cause typhoid fever, cholera, and E. coli which can kill

people. The World Health Organization (WHO)

considers disease-causing microbes one of the most

serious problems to health.

Chemical contamination is about metals and chemicals in water that are bad for your health. Water actually contains many chemicals, like sodium and calcium, most of which will not harm you. However, some chemicals if drunk over time are very risky especially for children. Heavy metals are can harm the kidneys, liver, nervous system, and bone structure. These metals and chemicals can come from natural sources, like volcanoes, and from industrial waste disposal and agriculture.

Physical contamination is about the water’s physical condition, for example colour, odour, temperature, and turbidity (cloudiness from small pieces of soil in water). Most of these will not harm your health, but they can be homes for bacteria and sometimes they make water unpleasant to drink.

How can we measure the water quality?

Water Flow: If the water is flowing (moving), then

oxygen is being put into the water. If the water is not

flowing, it becomes stagnant (dead) water.

Water Temperature: If the water temperature is too

high, this can limit the water’s ability to hold oxygen

which can kill organisms living there.

pH Testing: This measures the acidity of water. Most

aquatic organisms are only able to survive within a pH

range of 6 to 8.

Salinity Testing: This measures how much salt there is

in water. Many organisms and plant life cannot survive

if the water becomes too saline (salty).

Dissolved Oxygen Test: This measures the amount of

oxygen dissolved in water. Without this, aquatic life

cannot survive.

Total Dissolved Solids: This measures how many

minerals, salts, and metals are dissolved in water.

These come from natural sources, sewage, industrial

wastewater, chemicals used in the water treatment

process, and the pipes used to send the water to your

home or office.

Turbidity Test: This measures how much matter that is

in the water or how clear the water is. If turbidity is

high, water plants cannot get the sunlight they need.

We can measure simply by looking at how transparent

the water is.

It is important to test water regularly to check

for any changes in water quality. It is also

important to test water if an emergency

happens, like a a chemical spill.

Why could the water change? 1. Soil can get into water because of

erosion, land clearing, and overgrazing.

2. Chemicals can get into water because

of fertilisers, pesticides, and leaching.

3. Pollution can get into water because of

refuse from factories, sewage systems,

mines, and service stations.

4. Pollution can get into water because

of rubbish disposal (from landfills).

There are SEVEN types of water:

Tap water: This is the water from your tap. It may not be

good enough to drink, but we can use it for cleaning,

cooking, gardening, and washing clothes.

Mineral water: This water that contains minerals from

underground. It has lots of calcium and magnesium. It has a

reputation as healthy drinking water and has a salty taste.

Spring water: In some places, rainwater underground leaks

out as a spring, but this water is not suitable for drinking as

it comes from under the ground.

Well water: When it rains, water trickles down and travels

through the gaps in soil to create underground lakes. This is

called groundwater. A well can bring this water up to the

surface.

Purified water: This water has been cleaned (purified) at a

water treatment plant. This involves removing all bacteria,

contaminants, and dissolved solids making it suitable for

drinking. You can buy it from supermarkets or use a water

purifier at your home.

Distilled water: This water is treated to remove all minerals

and salt. It is completely pure water, but it is not

recommended for drinking because it does not have any

minerals or salts that we need for healthy living. This water

could be used in a car battery.

Sparkling Water: You can find this water at restaurants. This

water has been carbonated (add carbon dioxide) which

makes water fizzy, just like pepsi. Sparkling water may be

spring water, purified water, or even mineral water.