Grade 8 Integrated Science Chapter 20 Lesson 3 on human impacts on water. This lesson goes into detail on how humans positively and negatively impact our water resources. The objective is that students will be able to identify point and non-point source pollution, international cooperation and national initiatives to manage water resources, and how we can prevent polluting our water supply.

1. Chapter 20 Lesson 3
p734-740
IMPACTS ON WATER

2. Water as a Resource
 Most of Earth’s surface is covered with water,
and living things on Earth are made mostly of
water.
 Like other organisms, humans need water to
survive.
 Humans also use water in ways that other
organisms do not.
 People wash cars, do laundry, and use water for
recreation and transportation

3. Water as a Resource
 Household activities, however, make up only a
small part of human water use.
 Most water in the United States is used by
power plants.
 The water is used to generate electricity and to
cool equipment.
 The use of water as a resource also impacts the
environment

6. Sources of Water Pollution
 Water moves from Earth’s surface to the
atmosphere and back again in the water cycle.

7. Point-Source Pollution
 Point-source pollution is pollution from a
single source that can be identified.
 Discharge pipes that release industrial waste
 Oil spilling tankers
 Runoff from the mining operation

8. Nonpoint-Source Pollution
 Pollution from several widespread sources that
cannot be traced back to a single location is called
nonpoint-source pollution
 As precipitation runs over Earth’s surface, the water
picks up materials and substances from farms and
urban developments.
 These different sources might be several kilometers apart.
 This makes it difficult to trace the pollution in the water
back to one specific source and is harder to control.
 Examples:
 Farm and urban development runoff
 Construction site runoff which contain excess amounts of
sediment

10. Positive Actions
 Once pollution enters water, it is difficult to
remove.
 In fact, it can take decades to clean polluted
groundwater!
 That is why most efforts to reduce water
pollution focus on preventing it from entering
the environment, rather than cleaning it up.

11. International Cooperation
 In the 1960s, Lake Erie, one of the Great
Lakes, was heavily polluted by runoff from
fertilized fields and industrial wastes.
 Rivers that flowed into the lakes were polluted,
too.
 Litter soaked with chemicals floated on the
surface of one of these rivers – the Cuyahoga
River.
 The litter caught fire which spurred Canada and
the United States – the two countries that border
the Great Lakes – into action.

14. International Cooperation
 The countries formed several agreements to
clean up the Great Lakes.
 The goals of the countries are pollution
prevention, as well as cleanup and research.
 Although, the Great Lakes still face challenges
from aquatic species that are not native to the
lakes and from the impact of excess
sediments, pollution from toxic chemicals has
decreased.

15. National Initiatives
 In addition to working with other governments,
the United States has laws to help maintain
water quality within its borders.
 The Clean Water Act, for example, regulates
sources of water pollution, including sewage
systems.
 The Safe Drinking Water act protects supplies
of drinking water throughout the country.

18. How can you help?
 Laws are effective ways to reduce water
pollution. But simple actions taken by
individuals can have positive impacts, too.

19. Reduce Use of Harmful
Chemicals
 Many household products, such as paints and
cleaners, contain harmful chemicals.
 People can use alternative products that do
not contain toxins.
 For example, baking soda and white vinegar are
safe, inexpensive cleaning products.
 In addition, people can reduce their use of
artificial fertilizers on gardens and lawns.
 Compost can also enrich soils without harming
water quality.

20. Dispose of Waste Safely
 Sometimes using products that contain
pollutants is necessary.
 Vehicles, for example, cannot run without
motor oil.
 This motor oil must be replaced regularly.
 People should never pour motor oil or other
hazardous substances into drains, onto the
ground, or directly into streams or lakes.
 These substances must be disposed of safely.

21. Conserve Water
 Water pollution can be reduced simply by
reducing water use.
 Easy ways to conserve water include taking
shorter showers and turning off the water
when you brush your teeth.