Environmental problems are not confined within political borders. The oceans, rivers, lakes, and air are
shared by the world’s inhabitants. If a corporation or a nation pollutes, the world’s citizens are the
victims. If the tropical forests are destroyed, we are all affected. If a country wastes finite resources or
uses more than its proportionate share, the other nations are shortchanged.
• Ecology refers to the study of the interaction of living organisms and the natural environment.
• The natural environment refers to the earth’s surface and atmosphere, including various living
organisms, as well as the air, water, soil, and other resources necessary to sustain life.
1) Land Pollution
• Increasingly, humans are polluting the land with toxic and nuclear waste, solid waste, and pesticides.
• In 1960, each U.S. citizen generated 2.7 pounds of garbage on average every day; by 1996, this figure
increased to 4.3 pounds. The U.S. discards nearly 160 million tons of solid waste each year, enough to
bury 2,700 football fields in a layer ten stories high. Some of this waste is converted into energy by
incinerators, but more than half is taken to landfills.
• In the U.S., about 500,000 tons of 600 different types of pesticides are used annually. Pesticides
contaminate food, water, and air and can be absorbed through the skin, swallowed, or inhaled.
2) Water Pollution
• Our water is being polluted by a number of harmful substances, including pesticides, industrial waste,
acid rain, and oil spills. In 1993, there were more than 9,000 oil spills in and around U.S. waters alone,
totaling more than 1.5 million gallons of spilled oil.
• 500 million pounds of toxic waste are absorbed by our water supply each year. About 1.2 billion
people lack access to clean water. In developing nations, as much as 95 percent of untreated sewage is
dumped directly into rivers, lakes, and seas that are also used for drinking and bathing.
3) Air Pollution
• Air pollution levels are the highest in areas with both heavy industry and traffic congestion, such as Los
Angeles and Mexico City. Motor vehicles, fuel combustion, indus