The pollution of the earth’s soil and water has become an issue of great concern. Until recently, most of that concern has focused on the land portion of the planet, where pollution directly affects people in their daily lives. Now, however, we have begun to realize that marine pollution is equally important. According to Patin (1982, pp. 3-4), marine pollution is the condition that results when people introduce into the seas substances harmful to life, health, resources, activities, or comforts.
Marine pollution is far from new. For over a million years, people have thought of the sea as a convenient place to throw their garbage. And it is true that Q2. the sea has a great capacity for absorbing organic wastes. Some of these wastes are eaten directly by the larger fishes. Others quickly decompose in sea water, i.e., they dissolve into a kind of organic soup that provides food to countless species of single-celled plant and animal life.
As civilizations grew, more and different pollutants were dumped into the seas. Still, this pollution did not really threaten the marine environment. The seas seemed capable of coping with anything that people could throw at them. This situation changed abruptly, Q2. however, with the onset of the Industrial Revolution. Suddenly, factories began dumping enormous quantities of materials into the seas. Especially in some coastal areas near large cities, ocean pollution began to threaten marine life. For the first time, the oceans began to fail in their ability to recycle humanity’s waste.
It is becoming clear that marine pollution is a threat not only to marine life but to human life as well. As we have seen, one of the major ways we pollute the seas is to throw into them various types of waste and materials foreign to the marine environment. It is important to identify these different types of pollutants and to understand the effects of each on marine and human life.
Q1. Marine pollutants fall into two major categories: bio degradable and non-biodegradable substances.
Q3. Biodegradable substances are materials that can be taken apart by natural processes within a short time. Such materials are usually not very harmful. One common biodegradable pollutant in the oceans is Q1. human waste from sewage. Marine biologist John L Culliney (p. 11) explains that in small quantities, it does not threaten the environment. In larger quantities, however it provides a habitat for bacteria, which use up all the available oxygen in the area. As a result, all the fish in the region die. Sewage also contains viruses that are harmful to humans. Shellfish, particularly clams and oysters, accumulate these viruses in large quantities. When people eat shellfish, they increase their chances of getting certain diseases. One such disease is polio, a viral disease causing paralysis and sometimes death. Another is hepatitis, a serious disease of the liver.
A greater threat to marine life and eventually to human life is Q1. various types of non-biodegradable substances. Q3. These are materials that cannot be quickly broken down into basic natural parts. One such material comes from Q1. plastic containers that are dropped overboard in large quantities from cruise ships. These containers break into tiny particles in the surf. Q4. The particles get stuck in the digestive systems of baby fish and one-celled creatures called plankton. By preventing the food from entering the bodies of these creatures, the small particles cause them to die (Culliney, 1979, pp. 12425). Q4.This has an effect on larger marine animals that depend on plankton for their food.
Another group of non-biodegradable pollutants mentioned by Culliney consists of the Q1. toxic chemicals that are dumped into the sea as wastes from factory production. Among these chemicals are the insecticide
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DDT and a class of industrial chemicals called PCB’s. All these chemicals have been closely linked with cancers in humans. In addition, small quantities of these chemicals affect the growth rate of many species and also make them less adaptable to normal environmental changes. In time, these effects could kill off entire species. In larger quantities, these toxic chemicals cause immediate death. Furthermore, the chemical poisoning of marine species can result indirectly in the poisoning of human beings. Some one-celled marine organisms readily absorb dangerous chemicals. As Culliney (1979, p 193) observes, “In laboratory experiments, 98 percent of the DDT or PCB stirred into a jar of seawater was absorbed by plankton in six seconds”. At first glance, the poisoning of plankton may not seem a cause of concern for humans, however, the very important process of food magnification is at work in the seas as elsewhere. In this process, the smallest forms of life, such as plankton, absorb dangerous chemicals from the sea. Larger animals eat the plankton over a wide area. These animals are in turn eaten by still larger predators over a much wider area. And the process continues right up the food chain to humans, who catch and eat the larger fishes. Any one of these fishes may contain poisons that were originally spread over many hectares of the ocean (Culliney, I99 p 194). In this way, toxic chemicals in the seas may be even more dangerous to people than to marine plants and animals. Furthermore, two or more toxic substances, when acting together, produce more harmful effects than they can produce individually. Hence, the many thousands of poisonous materials already in the oceans can lead to countless hazards (Culliney, 1979, p. 204).A third type of non-biodegradable substance that causes serious pollution is Q1. oil. Although oil leaks naturally into the sea from sources beneath the ocean bottoms, the quantities produced by this natural leakage are small. Humans, however, are responsible for the dumping of ten times as much oil into the seas (Culliney, 1979, pp. 256-257). Some areas, such as the Gulf of Mexico and the waters off the coast of southern California, have become badly polluted as a result of offshore oil drilling. Also, major oil spills, such as the Exxon Valdez disaster in Alaska in March 1989, have destroyed entire ecosystems. These may take decades or even centuries to recover As Culliney (1979, pp. 268-269) points out, oil can seriously weaken fish, especially at critical periods in their lives. In addition, oil can change the normal behaviours of fish and thus reduce the chances for survival. There is also a limit to the amount of oil fish can tolerate without dying.
Still another category of non-biodegradable pollutants is Q1. heavy metals such as cadmium, mercury, and lead (Palm, 1982, pp 5661). This type of marine pollution has had the most immediate and devastating effects on people. Kelp, a seaweed eaten by the Japanese, can concentrate cadmium in huge amounts.
Cadmium has been linked to a degenerative bone disease in Japan. In Japanese, the disease is called itai-itai, meaning “ouch-ouch,” because of the extreme pain it causes (Culliney, 1979, p. 281). And in 1965, six people in Nigata, Japan, were killed and forty one were crippled from eating fish that contained mercury.
Of course, these metals affect fishes as well. Even low levels of heavy metal pollution appear to be harmful to almost all species of marine life (Patin, 1982, p. 148).
Recognizing the types of marine pollution and understanding their effects on marine and human life are essential. The next step is to identify areas where marine pollution disasters are most likely to occur.
According to chemist and oceanographer Edward D Goldberg (1976, pp. 142-146), the greatest risks will be in countries with large populations and large ratios of gross national product to area. Chances are even greater for island countries or for countries where most of the population lives near the ocean. It is no surprise, therefore, that the most serious ocean poisoning incidents to date have occurred in Japan and the United States. Other high-risk areas include Hong Kong, Singapore, and the Netherlands. At the bottom of the list are the developing countries of the Third World.
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All nations, but especially high-risk countries, must consider how to solve the problem of marine pollution.
Their solutions may determine the fate not only of marine plants and animals but of all humankind. In his book After man: A zoology of the future, Dixon (1983) used his scientific knowledge and artistic imagination to picture the earth millions of years from now. His world consists of a wonderful variety of plants and animals that have evolved far beyond their ancestors that are living today. Only one animal is missing from the scene: people. Why did our species finally vanish from the earth? Was there a nuclear war or a
worldwide epidemic of some deadly, uncontrollable disease? According to Dixon, the extinction of our species was unavoidable and without glory. Our descendants died from a lack of the resources that they had wasted and from the poisons of their own garbage and pollution
References
Culliney, J. L. (1979). The forests of the sea. New York, NY: Anchor Books.
Dixon, D. (1983). After man: A zoology of the future. New York, NY: St Martin’s Press Goldberg, E. D. (1976). The health of the oceans. Paris, France: The Unesco Press
Gross, M. G., & Palmer, H. D. (1979). Waste disposal and dredging activities: The geological perspective In H D Palmer & M. G. Gross (Eds.). Ocean dumping and marine pollution (pp. 1-7). Stroudsburg, PA:
Dowden, Hutchinson & Ross.
Patin, S. A. (1982). Pollution and the biological resources of the oceans. Translated by Freund Publishing House. London. Butterworth
* NB: Most answers are found in several different parts of the text.*
Checking Your Comprehension
1. List the main marine pollutants. Biodegradable (eg. sewage) & non-biodegradable (plastic containers, toxic chemicals, oil & heavy metals).
2. Why was ocean pollution not a serious problem before advanced technology? After the Industrial Revolution, the ocean could no longer cope with the quantity of waste dumped in the sea.
3. What is the difference between biodegradable and non-biodegradable pollution? Biodegradable pollutants break down fast naturally, but non-biodegradable cannot.
4. From what you have read here, can you think of a way to use a living species to test the degree of pollution in water? eg. By testing plankton or creatures that eat them, scientists could ascertain the amount of chemicals and/ or plastic in the sea.
Analyzing the Structure
1. Which paragraphs in the reading passage contain the introduction, the body, and the conclusion?
Introduction: Paras 1-4; Body Paragraphs: 5-9; Conclusion: 10
2. Identify the thesis statement of the passage. In what way does the passage fulfil the requirements of the thesis statement? Paragraphs 5-8 classify the types of pollutants and describe their effects.
3. Rewrite the definition of the word itai-itai in one sentence, including the class and characteristics. eg:
Itai-itai is the Japanese name for a degenerative bone disease caused by a concentration of cadmium found in seaweed that is eaten, and is characterised by extreme pain, crippling or death.
For Discussion
1. What are some steps that individuals could take to help reduce ocean pollution?
2. Discuss the statement, “There is only one pollution . . . people”.
3. What human activities would be affected by extreme pollution of the oceans?
Healy, J. (2003). Adapted from: Bradsher, K. (2002). High and mighty: SUVs - The world's most dangerous
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vehicles and how they got that way. In GLW, March 12th, 2003. Public Affairs Press.