This essay concentrates on five major causes of marine pollution, which are the discharge of domestic and industrial wastewater, waste oil, plastics, heavy metals and aquaculture. The proposed solution to this problem will be prevention and pollution treatment, and eventually, the former one proves to be more effective. Firstly, this essay will present and explain the major causes and effects of marine pollution. Then, different solutions will be suggested in the second part. The final part will evaluate the effectiveness of these solutions and show that prevention may be more successful.
The first main cause of the marine pollution is the discharge of domestic and industrial wastewater. Since both the cities and industrial estates are crowded with lots of people, there is more sewage flowing into rivers and then into oceans. Therefore, the quality of seawater gets worse and oxygen content decreases rapidly. Without oxygen, fish living under the sea can not survive. Because of the nutrients in the sewage, seaweed may grow well firstly and eventually die when running out of food. So the wastewater will finally destroy ecological balance for the reason of the discharge of domestic and industrial wastewater.
Then waste oil is another significant cause of marine pollution. After leaking from ships, or spilling in accidents, or flowing out of factories, waste oil enters oceans. The total amount of waste oil is surprisingly great. Then the waste oil floats on the water and drifts with winds for it is lighter than water. Several elements in the waste oil are harmful to the living of creatures, especially to the living of seabirds. The oil sticks to the wings of seabirds so they can not fly and die on the sea one after another. It is also poisonous for fish and sea plants. So it is obvious that waste oil may let many creatures to run into danger of dying out.
The third major cause of marine pollution is plastics. Plastics are the main solid pollutants and people treat the oceans like a giant dustbin to pour plastics in. Kusui and Noda’s research showed that in the seashore of Japan, if there are 100 waste items thrown by people, 73 items are plastics, and the plastic litter equals 53.8% of the total litter of wastes. In the neighbouring Russia, the statistics are 55 items and 23.4% respectively (Islam, 2004). The plastics can block the propeller of ships, and may cause enormous accident. Plastics floating in the oceans can also cause lack of oxygen and have the similar effects, preventing respiration of creatures, as the sewage does. When the plastics break down in the oceans, they can be toxic to marine plants and animals. Therefore, plastics are not only harmful to ships sailing in the oceans and mankind, but also to other creatures living in the seas.
Heavy metals are the fourth main cause of the environment problem. There are various sorts of heavy metals contained in water from factories. They go into the oceans through rivers or water run-off. Then they are eaten by fish and begin to accumulate in their bodies. When these fish are caught by us human beings, heavy metals enter our bodies and make us ill. Heavy metals can cause serious diseases.
Aquaculture is the final major cause to marine pollution. People usually cultivate fish and other marine life for food. But the foods which they use to feed marine life consequently harm the marine environment where there are people live around. It is because these foods are organic matter and will become rotten in the oceans gradually. The quality of seawater is reduced by this kind of substance and the marine life living in this ocean area and adjacent ocean area will die. Thus, aquaculture will cause harm to the quality of seawater of large areas of oceans.
There are two main solutions to the marine pollution problem. Prevention comes out first. It is suggested that governments should perfect new intendance system of protecting the quality of water that we should make water completely clean before it is discharged to the oceans. It is also necessary to establish laws to keep the conduct of people and enterprises, and develop cooperation among different countries. The second main solution is pollution treatment, which contains setting up treatment plants and planting trees. In Kocasoy, Mutlu, and Alag?z’s study (2008),  these solutions can reduce the discharge of domestic and industrial wastewater as well as improve the quality of seawater. Since trees are able to make soil secure and hold back water from running off, they can be planted in the crowded cities and factories which cause marine pollution. Treatment plants are used to cleanse the seawater.
Considering the advantages and disadvantages of the two solutions, prevention of marine pollution will be more effective to solve the problem. In one hand, prevention is the most essential theme of environmental management. The monitoring of water quality can be put into practice in advance to prevent damage to ocean environment. To improve attitudes of people and enterprises towards pollution will obviously be helpful and it is feasible to bringing these limits to maintain the marine environment in good condition. In the other hand, always firstly polluting the marine environment and then taking counter-measures as treatment is irresponsible behaviour. Although these measures can reduce pollution to some extent, the disastrous
consequences may have already existed, and marine pollution will continually come into being and never end. Consequently, prevention is much better in solving the pollution problem.
This essay considers the main causes and effects of marine pollution. The five causes are the discharge of domestic and industrial wastewater, waste oil, plastics, heavy metals and aquaculture. They can destroy the ecological balance, endanger many creatures of dying out, harm ships, human beings and other creatures, cause serious diseases to mankind, and cause harm to the quality of seawater of large areas of oceans. The solutions are prevention and pollution treatment. The prevention of marine pollution is proved to be more effective than pollution treatment because it can basically solve this problem and maintain the marine environment in a good condition. In my opinion, it is a challenge for governments to take proper measures to prevent people continuing polluting behaviour. However, there is still a long way to go in the future.