Earth Science

Human Impacts on the Earth Environment

Safety of Water

Study Tip
Nearly one-fifth of the world population has no access to clean water.

Water Treatment

  • Unsafe water contains many pathogens, which causes a variety of diseases.
  • Natural sources of water are treated with disinfectants such as chlorine, to kill bacteria and other microscopic pathogens.
  • In most communities in the United States, water undergoes a lengthy process before ending up in drinking fountains.
Study Tip
Nearly one-fifth of the world population has no access to clean water.

Water Treatment Process

The water treatment process involves the following five steps:

  • Coagulation
  • Sedimentation
  • Filtration
  • Disinfection
  • Storage

Effects of Water Pollution

  • Drinking unsafe water causes approximately 88% of all diseases.
  • Throughout the world, more than 14,000 people die every day from waterborne diseases such as cholera and Guinea Worm disease.
Water Treatment Process
Concept Check
  • What do waterborne diseases from unsafe drinking water lead to?
  • How is water treated in many communities across the United States?