(c) McGraw Hill Ryerson 2007

12.3 Water Quality and Its Effectson Living Things

• Human activities are having many negative impacts on the water cycle.

See page 454

Water Quality and Its Effect on Living Things

• We are adding far too many waste materials to the water system, and many wastes that do not break down quickly or efficiently.

• We are removing far more water from natural sources than the water cycle can naturally replace.

• Human demands for fresh drinking water and industrial water supplies increase every year.

(c) McGraw Hill Ryerson 2007

(c) McGraw Hill Ryerson 2007

Sources of Water Pollution

• Pollution = materials harmful to the environment.• Point source pollutants

Point sources of pollution refer to locations that can be directly traced as the source of a pollutant entering the environment.

Examples include oil spills, waste-water pipes emptying into rivers, or a landfill leak into the groundwater.

See page 455 - 456

Sources of Water Pollution

• Non-Point source pollutants Non-point sources of pollutions come from many

sources, and cannot be traced back to one single source. This makes them very difficult to control.

Examples include run-off from industry, dog parks and farms.

Groundwater is very susceptible, since it canbe contaminated for hundreds of years.

(c) McGraw Hill Ryerson 2007

(c) McGraw Hill Ryerson 2007

The Effects of Water Pollution

• Humans have large demands for water, but we also are responsible for endangering its quality. chemical - acid rain, pollutants physical - oil spills, hydro projects biological - bacteria, wastes

See page 457 - 458The remains of this albatross chick

show how plastics can affect marine life.

The Effects of Water Pollution

• Oceans cannot decompose the large amounts of wastes, or their toxicity, that enters primarily along coastal areas.

• Plastics decompose over thousands of years, and can cause great damage to wildlife.

(c) McGraw Hill Ryerson 2007

(c) McGraw Hill Ryerson 2007

• Oil pollution in oceans comes primarily from non-point sources such as people changing oil in their cars and pouring the used oil down the drain.

• Oil spills from tankers can be tragic, but occur infrequently. Small spills from pleasure craft and smaller boats add a constant, high-volume of pollution to the marine environment.

The Effects of Water Pollution

See pages 457 - 458

Acid Precipitation

• Acid precipitation contaminates all bodies of water. The main sources of acid precipitation are

nitrogen oxides and sulfur dioxides from the burning of fossil fuels. Burning coal, gas and oil is a primary source of energy.

Nitric acid and sulfuric acid are produced, and fall as acid precipitation

(c) McGraw Hill Ryerson 2007

(c) McGraw Hill Ryerson 2007

Acid Precipitation

• Water is naturally acidic, but the acidity increases from acid precipitation.

• This + other pollutants then enter the groundwater, fresh water and salt water environments.

See page 459 - 460

Take the Section 12.1 - 12.3 Quiz