Pollution

Since the mid-20th century, people have become more and more aware of how various forms of pollution are poisoning Earth and reducing the survival chances of every form of life. Consider these facts about pollution from the U.S. Environmental Protection Agency and other pollution-watch groups.

Pesticides. Americans use some 2.2 billion pounds of pesticides every year – poisons to which the target pests quickly develop resistance. U.S. groundwater, the source of much drinking water, has been found to harbor 73 different kinds of pesticides. More than 100 active ingredients in pesticides have been linked to cancer, birth defects and gene mutation. Researchers are finding that more and more pesticides disrupt immune and endocrine systems and have long-term impacts on human and animal offspring. In addition, 41 percent of all U.S. agricultural insecticides are applied to corn. Eighty percent of these are intended to treat a pest that could be controlled more effectively by rotating the corn annually with any other crop.



Nuclear waste. For an amount equivalent to the cost of one nuclear weapons test, 80,000 hand pumps could be installed in the villages of developing countries to provide clean water. Meanwhile, the EPA estimates that it will cost U.S. taxpayers between $100 billion and $400 billion to clean up 24,000 contaminated federal nuclear facilities.

Toxic chemicals. U.S. factories emit 3 million tons of toxic chemicals annually into the air and water, and onto land. In 1987, the United States released 1.2 million tons of toxic chemicals into the Earth's atmosphere, 670,000 tons into the soil, and 250,000 tons into the water, according to International Wildlife magazine. What's more, although PCBs have been banned for more than 20 years, "dangerous" levels of PCBs remain in the environment, threatening biological life. While essential for crops, too much nitrogen leaking into water sources causes nutrient pollution in streams, rivers and oceans, and results in nitrate pollution that harms humans.

Air pollutants. Gases in the atmosphere can have beneficial effects in one part, but cause serious problems in other situations, For instance, ozone, a colorless gas, is the major component of smog at the Earth's surface, but helps protect the planet from harmful solar radiation in the upper atmosphere. At the surface, ozone can irritate the respiratory tract, impair lung function and cause chest pain, cough, and lung inflammation. Meanwhile, carbon monoxide, an odorless and colorless gas emitted in the exhaust of motor vehicles reduces the blood's ability to deliver oxygen, affecting the cardiovascular and nervous systems. Nitrogen dioxide, a light brown gas that produces brown urban haze, causes acid rain and smog, and can harm both people and plants in high concentrations. Another major component of smog is sulfur dioxide emitted mainly through burning fossil fuels; this chemical acidifies lakes and streams and harms people who suffer from asthma. Other toxic air pollutants includes arsenic, asbestos, benzenes and chlorofluorocarbons from industries, car exhaust, fuels, building materials, household refrigeration, car and home air conditioners and products made of plastic foam.

Greater awareness of these pollutants in the past 50 years or so have led many industries to change their processes or the components of their products. For example, interior and exterior paints are now made without lead, a major threat to children, and without volatile organic compounds (VOCs) that contribute to air pollution.