Composition of Water
- We use water in many aspects of our everyday life:
- Domestic uses: for drinking, cooking, gardening and general sanitation
- Agricultural uses: as a drink for animals and watering crops
- Industrial uses: as a solvent, as a coolant and heated to make steam used to generate electricity
- Water is found in natural sources such as lakes, rivers and underground water sources (groundwater)
- A rock that stores water is known as an aquifer
- Water from natural sources may contain a variety of different substances including:
- Dissolved oxygen
- Dissolved carbon dioxide from rainwater (which lowers the pH of water)
- Metal ions (E.g. Ca2+, K+, Na+, Mg2+)
- Plastics
- Sewage
- Harmful microbes
- Nitrates from fertilisers
- Phosphates from fertilisers and detergents
- Some of these substances are classed as pollutants
- Pollutants can either be natural or man- made
- Natural pollutants enter water sources when rain falls and washes them into lakes, rivers or groundwater
- These include bacteria and viruses
- Man made pollutants are a direct result of human activities
- These include fertiliser, pesticides and household and industrial waste
Photo by Ben Clayton on Unsplash
Exam Tip
Despite the term 'natural source’, water from these sources may contain lots of impurities and harmful substances and should not be confused with water which is clean and ready for use.
