CONSERVATION (Part 4 of 5)

Refuges for Wildlife

Some governments have established national wildlife reservations and game refuges. Many refuges are established in places to which animals, especially migratory birds, have long been attracted. In the United States, many of these are administered by the Fish and Wildlife Service. All the national parks and national monuments are wildlife refuges.

Individuals can help restore wildlife to the countryside simply by providing birds, fish, and animals with natural breeding sites. They can do even more by encouraging their state and federal governments to provide effective laws for habitat protection.

For a long time, many people believed salt marshes were just worthless land. Salt marshes became dumps for garbage, or they were filled in to make the land more useful to humans.

Now we know that marshes are habitats for many different land and water creatures. They often act as "nurseries," providing a safe shelter where animals can hide, and their young can grow into adults.

These marshes may produce and protect the greatest numbers and variety of wildlife on Earth.

Brush piles scattered through a wood lot provide retreats for cottontails, weasels, mink, and woodchucks. Fence rows can provide a haven for many kinds of birds. Marshes seldom make good crop lands, but they provide homes for muskrats and certain birds. Unfortunately, many of the salt marshes of the Atlantic coast have become dumping grounds for litter and industry. Others have been filled in to provide land for housing or for boat marinas. The birds and other animals that lived in those marshes, such as marsh hawks and short-eared owls, had to seek other habitats because their food supply and cover were gone. Continued exploitation of the marshes will further reduce the number of wildlife species.

FOREST CONSERVATION

Among the most valuable of nature's resources are forests. They play a key role in the maintenance of the watersheds that are essential to water and soil conservation. They shelter many forms of wildlife. They supply lumber for construction, cord wood for fuel, and pulp for paper. Forests also provide the raw materials used in many synthetic products considered essential for modern life, including fibres, plastics, and medicines.

Fire can be a major scourge of a forest. Although lightning is sometimes responsible for kindling forest fires, human carelessness is most often the cause. Ground fires can destroy the organic soil of the forest and render it incapable of supporting tree life. When crown fires rage through the leafy tops of trees, they destroy timber and its resident wildlife.

However, fire can also be a natural occurrence, and most forests rebound from occasional fires and the wildlife returns.

Insect infestation can also threaten the life of a forest. The Forest Pest Control Act of 1947 authorized surveys of public and private forests so that insect-borne diseases of trees could be detected and suppressed before they became epidemic.

Forests are a renewable resource that can provide us with goods for many years if logging is done carefully.

Most loggers cut small patches of trees out of a forest, leaving mature trees around the cut area. The mature trees ...

• reseed the cut area and produce new trees.
• form a net with their roots that keeps the soil in place, thus controlling erosion.
• provide a canopy of leaves that keeps rain from hitting the ground as hard as it would if there were no mature trees. If the rain beats down too hard, it erodes soil and prevents seeds from growing.

A more serious threat than fire or insects is indiscriminate logging. When every tree of a stand is cut without any provision for natural reseeding or manual replanting, no canopy is left to protect the soil against the splash erosion of rainfall. The loose soil soon becomes deposited as silt in nearby streams. Timber must be treated as a renewable crop, carefully harvested to ensure a sustained yield of trees. In this way, a balance is struck between the cutting of mature trees and the growth of saplings.

MINERAL CONSERVATION

Minerals are non-renewable resources. Once exhausted, they can never be replaced. The United States has valuable stores of coal, oil, natural gas, and minerals. Until the Mineral Leasing Act was passed in 1920, the resources on public lands were transferred to private individuals, who sometimes exploited them. Government regulation now helps private industry make proper use of these resources.

Coal, gas, and oil are non-renewable resources that we may soon run out of. We have tried to conserve coal, gas, and oil by ...

• making mining processes less wasteful.
• using other sources, such as nuclear power, for energy.
• improving the machines that burn coal, oil, and gas so that they don't need as much fuel to run.

One machine we have improved is the car engine. Today cars travel more miles on one gallon of gasoline than cars of the past did.

While one method of conserving resources may seem to make only a small difference, the use of many different methods can add up to big resource savings.

For years coal was mined as though it were inexhaustible about one ton wasted for each ton mined. The Bureau of Mines and other government agencies have promoted more efficient mining methods. In addition, the use of other sources of energy in home construction and in industry, and to generate electricity, has greatly extended the life of the coal supply. In order to conserve the dwindling supplies of natural gas and petroleum, in 1978 the government established requirements for conversion from these fuels to coal. But coal burning can create pollution problems.

Natural gas and petroleum were once carelessly wasted also. In earlier days, for example, because no use for natural gas had been found, it was burned off or allowed to escape into the air. Several government agencies now carry out programs to conserve these resources by replacing them with more abundant sources of energy. In 1978 the government established restrictions on the use of natural gas and petroleum in new industrial facilities and power plants.

Like other conservation needs, the wise management of mineral resources has become more pressing because of the growing number of consumers. As the human population increases, a need is generated for more consumer goods, such as household appliances and automobiles. Manufacturers must meet these rising demands from already dwindling deposits of metal ore. Under the Office of Fossil Energy Research, a program was set up that is concerned with increasing domestic supplies.

Some mineral resources, particularly metals, may be recycled that is, salvaged and reused. The recycling of waste metals is an important conservation practice that has become a major business. It is known as secondary production.

Throughout most of its history the United States has had ample, inexpensive supplies of fuels to provide energy. During the 20th century the country gradually shifted from reliance on coal as its principal fuel to dependence on natural gas and petroleum. By the late 1970s the United States was consuming more than one third of the world's supply of these two fuels and was dependent on them for three fourths of its energy.

As it became more apparent during the 1970s that natural gas and petroleum resources might be depleted within the foreseeable future, energy conservation became an important government policy. Conservation measures were also adopted because of political and economic developments. About one half of the petroleum used by the United States was imported, much of it from Middle Eastern countries that opposed certain United States foreign policies. In addition, oil-exporting countries increased oil prices by more than 1,500 percent between 1970 and 1980.

In 1977 President Jimmy Carter established a Cabinet-level Department of Energy and proposed a comprehensive energy program. As passed by Congress in 1978, the program included measures to discourage energy consumption, particularly of natural gas and petroleum, and provided incentives for alternative energy sources. An Energy Security Act, to develop synthetic fuels, was passed in 1980.

Government, industry, and private citizens all took steps to conserve energy. To meet new government standards, smaller and more efficient automobiles were produced. There was renewed emphasis on improving the country's mass transportation systems.

Grants, loans, and tax credits were offered for the installation of insulation and other energy-saving devices in homes and commercial properties. Efficiency standards for appliances were adopted. The government mandated minimum and maximum temperatures for non-residential buildings and suggested maintenance of similar temperatures in homes.

Until the energy crisis of the 1970s, people did not realize how much oil comes from sources outside the United States.

Many United States citizens don't want to be dependent on others for energy. They fear such dependence might give foreign nations too much power over the United States.

If the United States can find other sources of energy that will always be available, there will be less worry about using so much foreign oil. This is why the government has supported research to find new ways to get energy from sources such as the wind, the sun, and the ocean.

The energy crisis of the 1970s led to increased emphasis on alternative sources of power. The government supported further development of solar, geothermal, and wind power. Industries and utilities were encouraged, and in certain circumstances required, to use coal as an alternative to natural gas and petroleum. The government encouraged long-range research programs, including the development of economical methods of producing gas and oil from coal and shale. Gasohol a mixture of alcohol produced from grain and gasoline was tried as an alternative fuel for automobiles, and development of a battery-powered automobile continued.

With the election of Ronald Reagan in 1980, the government support for most of these programs was ended. Instead, the government promoted the expansion of nuclear energy and a return to imported petroleum.

ENVIRONMENTAL POLLUTION (Part 2 of 2).

Water Pollution

Since the beginning of civilization, water has been used to carry away unwanted refuse. Rivers, streams, canals, lakes, and oceans are currently used as receptacles for every imaginable kind of pollution. Water has the capacity to break down or dissolve many materials, especially organic compounds, which decompose during prolonged contact with bacteria and enzymes. Waste materials that can eventually decompose in this way are called biodegradable. They are less of a long-term threat to the environment than are more persistent pollutants such as metals, plastics, and some chlorinated hydrocarbons. These substances remain in the water and can make it poisonous for most forms of life. Even biodegradable pollutants can damage a water supply for long periods of time. As any form of contamination accumulates, life within the water starts to suffer. Lakes are especially vulnerable to pollution because they cannot cleanse themselves as rapidly as rivers or oceans.

A common kind of water pollution is the effect caused by heavy concentrations of nitrogen and phosphorus, which are used by plants for growth. The widespread use of agricultural fertilizers and household detergents containing these elements has added large amounts of plant nutrients to many bodies of water. In large quantities, nitrogen and phosphorus cause tiny water algae to bloom, or grow rapidly. When the algae die, oxygen is needed to decompose them. This creates an oxygen deficiency in the water, which causes the death of many aquatic animals. Plant life soon reduces the amount of open water. These events speed up the process of eutrophication, the ageing and eventual drying up of a lake.

Sedimentation also pollutes water. It is the result of poor soil conservation practices. Sediment fills water-supply reservoirs and fouls power turbines and irrigation pumps. It also diminishes the amount of sunlight that can penetrate the water. In the absence of sufficient sunlight, the aquatic plants that normally furnish the water with oxygen fail to grow.

Factories sometimes turn waterways into open sewers by dumping oils, toxic chemicals, and other harmful industrial wastes into them. In mining and oil-drilling operations, corrosive acid wastes are poured into the water. In recent years, municipal waste treatment plants have been built to contend with water contamination. Some towns, however, still foul streams by pouring raw sewage into them. Septic tanks and cesspools, used where sewers are not available, may also pollute the groundwater and adjacent streams, sometimes with disease-causing organisms. Even the purified effluent from sewage plants can cause water pollution if it contains high concentrations of nitrogen and phosphorus.

Farm fertilizers in some regions fill groundwater with nitrates, making the water unfit to drink. Agricultural run-off containing dangerous pesticides and the oil, grime, and chemicals used to melt ice from city streets also pollute waterways.

Land and Soil Pollution

In order to sustain the continually growing human population, current agricultural methods are designed to maximize yields from crop lands In many areas, the overuse of land results in the erosion of topsoil. This soil erosion, in turn, causes the over-silting or sedimentation of rivers and streams.

One of the most hazardous forms of pollution comes from agricultural pesticides. These chemicals are designed to deter or kill insects, weeds, fungi, or rodents that pose a threat to crops. When airborne pesticides drift with the wind or become absorbed into the fruits and vegetables they are meant to protect, they can become a source of many illnesses, including cancer and birth defects.

Pesticides are often designed to withstand rain, which means they are not always water-soluble, and therefore they may persist in the environment for long periods of time. Some pests have developed a genetic resistance to these chemicals, forcing farmers to increase the amounts or types of pesticide.

The pesticide DDT provides the best-known example of the dangers of introducing synthetic chemical compounds into the environment. Chemically a chlorinated hydrocarbon, DDT was widely used for many years after World War II. At first it was highly regarded because it reduced the incidence of malaria throughout the world. Then, evidence began to show that DDT might be doing more harm than good. DDT, like other chemically stable pesticides, is not readily biodegradable. It has been found in the tissues of every organism tested for its presence. DDT is now known to affect biological activities. It reduces the rate of photosynthesis in marine phytoplankton, organisms that form the basis of most ocean food chains.

Although DDT has been banned in the United States and most other countries, it is still manufactured and used in some parts of the world. Many other pesticides also have been banned. Thousands of pesticides remain in use and, in some cases, their agricultural value may balance out their risks.

Some urban areas are beginning to experience a serious problem regarding the disposal of garbage and hazardous wastes, such as solvents and industrial dyes and inks. In many areas landfill sites are approaching their full capacity and many municipalities are turning to incineration as a solution. Giant high-temperature incinerators have become another source of air pollution, however, because incineration ashes sometimes contain very high concentrations of metals as well as dioxins, a dangerous family of chemical poisons.

One answer to the garbage problem is recycling. Some towns have passed ordinances that encourage or require residents to separate glass and aluminium cans and bottles from other refuse so that these substances can be melted down and reused. Although lightweight steel, cardboard, and paper are also economically recyclable, most industries and cities still burn or bury large amounts of scrap metal and paper products every day.

Radioactive Pollutants

Cosmic rays, highly penetrating radiations reaching the Earth from outer space.

Radioactivity has always been part of the natural environment. An example of natural radioactivity is the cosmic radiation that constantly strikes the Earth. This so-called background radiation has little effect on most people. Some scientists are concerned, however, that humans have introduced a considerable amount of additional radiation into the environment.

Since the first atomic bomb was dropped on Hiroshima, Japan, on Aug. 6, 1945, there has been an increased awareness of the environmental threat posed by nuclear weapons and radioactive fallout. Many scientists are concerned about the long-term environmental impacts of full-scale nuclear war. Some suggest that the large amounts of smoke and dust thrown into the atmosphere during a nuclear explosion would block out the sun's light and heat, causing global temperatures to drop.

Even the testing of nuclear weapons directly affects the environment. Such tests are rarely conducted above ground or in the ocean. International concern over the effects of these tests led the United States, Great Britain, and the Soviet Union to sign the Nuclear Test-Ban Treaty in 1963.

On April 26, 1986, the Chernobyl nuclear power plant in the Soviet Union malfunctioned creating the worst peacetime nuclear disaster. Many details of the Chernobyl accident remain undisclosed, but it is known that the radioactive core of the power plant became exposed, and there was a partial meltdown, releasing large amounts of radioactive materials. Because the medical effects of exposure to nuclear radiation can take years to become apparent, it is not yet known how many additional cases of cancer, birth defects, and skin disease will have been caused by the Chernobyl accident.

Another immediate environmental problem is the disposal of nuclear wastes. Some radioactive substances have a half-life of more than 10,000 years, which means they remain radioactive and highly dangerous for many thousands of years. In nuclear physics, a half-life is the period of time required for the disintegration of half of the atoms in a sample of a radioactive substance. Science has not yet found a safe method of permanent disposal of high level radioactive wastes. Even temporary storage of these wastes is a dangerous and expensive problem. Experiments are under way to investigate the possible use of salt mines several thousand feet below the surface of the Earth as repositories for spent nuclear fuel rods and similar highly radioactive substances.

Thermal, or Heat, Pollution

While the concept of heat as a pollutant may seem improbable on a cold winter day, at any time of year an increase in water temperature has an effect on water life. Heat can be unnaturally added to streams and lakes in a number of ways. One is to cut down a forest completely. The brooks and streams that flowed through it are then exposed to the sun. Their temperatures begin to rise. As they flow into larger bodies of water, these in turn are warmed. This can kill fish and other water animals incapable of tolerating the higher temperatures.

Heat pollution is a consequence of the rising energy needs of man. As electric power plants burn fossil fuels or nuclear fuel to provide this energy, they release considerable amounts of heat. Power plants are usually located near bodies of water, which the plants use for heat-dissipation purposes. Some stretches of the Hudson River in New York no longer freeze in winter because of the flow of hot water into the river from adjacent power plants. Living things especially such cold-blooded animals as fish are very sensitive to even small changes in the average temperature. Because of the added heat in waters affected by power plants, many aquatic habitats may be undergoing drastic change. In some instances, the warmer water may cause fish eggs to hatch before their natural food supply is available. In other instances, it may prevent fish eggs from hatching at all.

In addition, a very small rise in the average temperature of the Earth's surface could produce profound climatic changes. Some experts believe that it would cause the Greenland and Antarctic ice caps to melt, raising ocean levels and inundating large areas of land.

Average worldwide temperatures can be affected when the products of combustion carbon monoxide, water vapour, and carbon dioxide are emitted into the air, especially at high altitudes. Since the normal level of carbon dioxide in the air is quite small, any significant addition is a potential threat. Although solar energy on its way to the Earth's surface easily passes through layers of carbon dioxide, some of the heat escaping from the Earth would be absorbed by increased amounts of atmospheric carbon dioxide, much as heat is trapped in a greenhouse. A worldwide greenhouse effect of this type might produce a dangerously warmer world. Since the late 19th century, the average global temperature has increased between 0.54°F and 1.08°F (0.3°C and 0.6°C). Internationally, 1990 was the hottest year on record since official weather records first started being kept by the British in about 1860.

Noise Pollution

The hearing apparatus of living things is sensitive to certain frequency ranges and sound intensities. Sound intensities are measured in decibels. For example, a clap of thunder has an intensity of about 100 decibels. A sound at or above the 120-decibel level is painful and can injure the ear. Noise pollution is becoming an unpleasant fact of life in cities, where the combination of sounds from traffic and building construction reverberates among high-rise buildings, creating a constant din.

In addition, the intense volume at which some popular music, especially heavy metal rock music, is played has resulted in the loss of some or all of the hearing of a few musicians and members of their audiences. There is some evidence that extreme levels of noise can produce other deleterious effects on human health and on work performance.

Efforts to Halt Pollution

The solution of some pollution problems requires cooperation at regional, national, and international levels. For example, some of the acid rain that falls in Canada is caused by smokestacks of coal-burning power plants in the United States. Thus, rejuvenating the lakes of eastern Canada requires the cooperation of electric utilities in Indiana and Ohio.

Greenpeace Foundation, international organization for the protection of the environment.

In the United States laws have been passed to regulate the discharge of pollutants into the environment. The Environmental Protection Agency (EPA), which was formed through the National Environmental Policy Act (NEPA) of 1969, oversees most federal anti pollution activity. The National Environmental Policy Act also mandated the use of environmental impact statements, which require that businesses or governments examine alternatives and acknowledge the possible harmful effects of such activities as opening new factories, building dams, and developing new oil wells. With the advent of massive oil spills from supertankers, the washing up of medical wastes on shores in New York and New Jersey, and an increased build-up of toxic wastes, such international organizations as Greenpeace have become ever more dedicated to preventing environmental abuses and heightening public awareness of environmental issues.

The Clean Air Act, the Safe Drinking Water Act, and the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (known as Super fund) are among the laws that set standards for healthy air and water and the safe disposal of toxic chemicals.

In 1990 President George Bush signed the Clean Air Act of 1990, the second amending legislation since the original Clean Air Act of 1970. The new law called for reductions in emissions of sulphur dioxide and nitrogen oxide by half, carbon monoxide from vehicles by 70 percent, and other emissions by 20 percent. The number of toxic chemicals monitored by the EPA would increase from 7 to about 250, and industry would be required to control their waste release by means of the best technology available. In the same year, the California Air Resources Board introduced the strictest vehicle-emission controls in the world. By 2003 the hydrocarbon emission of all new cars sold in California would have to be at least 70 percent less than that of 1993 models, and by 1998, 2 percent of all cars (rising to 10 percent by 2003) would have to release no harmful emissions at all. Several North-eastern states followed suit by introducing similar, though slightly less severe, controls.

Assisted by John H. Thomas, professor of biology at Stanford University, and Paul J. Allen, Director of Communications at the Natural Resources Defense Council, Washington, D.C.

BIBLIOGRAPHY FOR ENVIRONMENTAL POLLUTION

Caplan, Ruth. Our Earth, Ourselves (Bantam, 1990).

Carson, Rachel. Silent Spring (Houghton, 1987).

Luoma, Jon. The Air Around Us (Acid Rain Foundation, 1989).

Mott, Lawrie and others. Pesticide Alert (Sierra Club and National Resource Defense Council, 1988).

Newton, David. Taking a Stand Against Pollution (Watts, 1990).

Thackray, Sue. Looking at Pollution (David and Charles, 1987).

Trager, Oliver, ed. Our Poisoned Planet: Can We Save It? (Facts on File, 1989).

Tripathi, A.K. and Pandey, S.N. Water Pollution (South Asia Books, 1990).