First, the causes of pollution
1, pollution caused by ships
What is ship pollution? It means that the balance of marine ecosystem is destroyed due to various harmful substances such as ship manipulation, maritime accidents and ship dumping entering the ocean. Characteristics of pollution caused by ships: (1) Various pollutants are introduced into the sea by ships. (2) Pollutants entering the ocean are caused by human factors rather than natural factors, that is, the pollution behavior is subjectively manifested as human intention or negligence. (such as tank washing sewage and engine room sewage discharged into the ocean without treatment) (3) After pollutants enter the ocean, they cause or may cause damage to the marine ecosystem.
The pollution caused by ships mainly shows as follows: (1) The pollution source of ship operation, which is mainly caused by the intention or negligence of ship staff. For example, some crew members deliberately discharge the cabin washing sewage containing harmful substances into the sea, and the engine room staff deliberately discharge the engine room sewage containing dirty oil into the sea without treatment, while others discharge fuel into the sea because of their weak sense of responsibility. (2) Pollution sources of marine accidents, such as ship collision, grounding, hitting rocks and other accidents, and various pollutants, mainly fuel oil leakage and oil tank leakage caused by accidents, pollute the ocean. (3) Sources of pollution caused by ship dumping; This pollution source is mainly manifested in the production garbage, domestic garbage and sludge sewage that ships deliberately dump into the sea from the pollutants generated by cleaning polluted waterways. Therefore, ship pollution is one of the causes of marine pollution.
2. Marine pollution caused by offshore oil development.
China is rich in offshore oil reserves. At present, most developers mainly focus on offshore exploration and development. With the rapid development of offshore oil exploration and development, some drilling ships and oil platforms have artificially discharged a large number of wastes and oily sewage into the ocean. Therefore, offshore oil development is also one of the causes of marine pollution at present. To some extent, it has affected the natural environment of China offshore. The pollution of offshore oil exploitation to the ocean is mainly manifested in: (1) domestic garbage, production (work) garbage and oily sewage discharged into the sea. (2) Accidents such as accidental oil spill, oil spill and blowout occur. (3) Wastes and oily sewage generated in man-made and natural processes flow into the ocean. When oil enters seawater, the harm to marine life is very serious. After the oil enters the seawater, a large amount of dissolved oxygen in the seawater is absorbed by the oil, and the oil film covers the water surface, so that the seawater is isolated from the atmosphere, resulting in seawater hypoxia and marine life death. It is very harmful to young fish and fish eggs. Young fish hatched in oil-polluted seawater are distorted and lifeless, and oil films and oil blocks will adhere to a large number of fish eggs and young fish, causing them to die. Oil pollution makes economic fish, shellfish and other seafood smell oily. After living in polluted seawater for a long time, adult fish and shellfish accumulate some harmful substances in their bodies, which will endanger human health if they enter the market and are eaten by people.
3. The pollution of the factory to the ocean.
With the deepening of China's reform and opening up and the leap from planned economy to market economy, the utilization area of beach culture by coastal residents has expanded year by year. From fish farming, shrimp farming and crab farming to aquatic animals and plants with more economic value and exotic flavor than the above. The development of these aquaculture industries has promoted the prosperity of aquatic products market, enriched people's diet life and improved their diet level. It has increased farmers' economic income and created employment opportunities for some people. However, in recent years, seawater deterioration such as red tide often occurs in coastal areas of China. What caused it? Besides venting factors, there are also human factors. In addition to the two reasons mentioned above, there is also a very important reason, which is the pollution of the sea by land factories. The pollution of land factories to the ocean is mainly manifested in (1) paper mills and chemical plants on both sides of rivers connected with the sea discharging sewage into the ocean. (2) Industrial garbage and domestic garbage containing pollutants are dumped on river banks or rivers, and enter the ocean with the ebb and flow of river water or tide. For example, on 200 1, Tianjin Maritime Court accepted the case that farmers in Laoting County, Hebei Province 19 sued Qian 'an Painting and Calligraphy Paper Co., Ltd. and other five units for compensation for beach pollution damage, which is a typical case of Luyuan factory using sewage from the sea to cause marine pollution. In this case 19, the plaintiffs were all engaged in prawn and clam breeding in Xiaohezi (Luanhe River) coastal prawn and beach shellfish breeding area in Wangtan Town, Laoting County, Hebei Province. Luanhe River is located in Chengde City and Tangshan City, Hebei Province. From Chengde, it flows through Qianxi, Qian 'an, Luanxian, Luannan and Laoting in Tangshan, and enters the sea in Jianggezhuang, Laoting County. Luanhe River diverges in Luanxian County, and the tributary that enters the middle of Laoting finally flows into Xiaohezi and enters the sea at Xinhaizhuang, Wangtan Town. There are tens of thousands of acres of shrimp ponds and shellfish culture areas on both sides of Xiaohezi estuary. From late April to mid-May in 2000/kloc-0, some fishery waters on both sides of Xiaohezi estuary were polluted due to sewage discharged from the upper reaches of Luanhe River, and cultured prawns and shellfish died. The accident caused a total aquaculture area of 7056. 15 mu in the polluted waters on both sides of Xiaohezi estuary, including 656.1.15 mu for prawn aquaculture and 495 mu for shellfish aquaculture in tidal flats. On May 30th, investigators investigated the death scene of shrimp shells in Xiaohezizha culture area. The results showed that 67.96% of mussels died, and the average mortality rate of Penaeus japonicus was 565,438+0%. The cause of the accident was that industrial and mining enterprises along the Luanhe River in Tangshan discharged substandard sewage.