3.6 Pollution Modern civilizations affect the environment more than civilizations in the past for two main reasons: Human population size has drastically increased. Many new toxic and persistent chemicals have been invented to support our lifestyle. Toxic materials are called pollution when they are released into the environment. Common sources of pollution include pesticides, fertilizers, car exhaust, and product packaging. pollution acid precipitation

3.6 Acid Precipitation Sulfur dioxide and nitrogen oxides are air pollutants produced by industry and by burning fossil fuels. These pollutants combine with water vapour in the atmosphere to form acids that eventually fall to Earth as acid precipitation. pollution acid precipitation

Effects of Acid Precipitation 3.6 On Aquatic Ecosystems Acid precipitation makes rivers and lakes more acidic, harming species. Some lakes have limestone deposits nearby, which can neutralize acid rain. The Canadian Shield does not neutralize acid, so lakes on the Canadian Shield are vulnerable to damage from acid rain. neutralize

Effects of Acid Precipitation 3.6 On Terrestrial Ecosystems Acid rain chemically changes the soil by depleting the nutrients needed by plants. On Humans Acid pollution aggravates respiratory problems, causes cars and iron structures to rust, and damages statues and buildings. As a result, acid pollution costs billions of dollars each year. neutralize

Reducing Acid Precipitation 3.6 Even if acid rain were stopped, it could take hundreds of years for ecosystems to recover. Progress has been made in reducing sulphur dioxide emissions in Ontario. However, the rain in the Muskoka-Haliburton area is still 40 times more acidic than natural rain. Much of Canada’s acid precipitation comes from the United States, where high-sulfur coal is still widely used. Humans are beginning to change the acidity of the world’s oceans as carbon dioxide from fossil fuels dissolves in ocean water to form carbonic acid.

3.6 Oil Spills Water is our most precious renewable resource. Oil spills can be caused by accidents to oil tankers. Oil is toxic, slow to break down, and difficult to clean up. It forms large slicks that cover the ocean, beach, and seabed. Sea birds and seals are particularly vulnerable to oil spills. Methods used to help clean up an oil spill include: Skimming/vacuuming: Floating oil may be contained and vacuumed up. Bioremediation: Scientists are studying micro-organisms that are capable of feeding on oil. Burning: Oil floating on the surface is sometimes lit on fire so it burns away. Dispersal agents: Detergents may be used to break up the oil into smaller droplets. bioremediation