Background
The Intergovernmental Oceanographic Commission under UNESCO clearly defines marine pollution as: the direct or indirect introduction of material or energy into the marine environment due to human activities, causing or likely to cause damage Marine biological resources, endangering human health, hindering fishing and various other legal activities, impairing the normal use value of seawater, and reducing the quality of the marine environment, and other harmful effects.
Marine pollution (marinepollution) usually means that humans have changed the original state of the ocean and destroyed the marine ecosystem. Pollution caused by harmful substances entering the marine environment will damage biological resources, endanger human health, hinder fishing and other human activities at sea, and damage the quality of seawater and the environment. The vast ocean area and huge water storage make it the most stable ecosystem on earth for a long time. The various substances flowing into the ocean from land are accepted by the ocean, but the ocean itself has not undergone significant changes. However, in recent decades, with the development of the world's industry, ocean pollution has become more and more serious, causing great changes in the environment of local sea areas, and there is a tendency to continue to expand.
Classification
According to their source, nature and toxicity, marine pollutants can be divided into the following categories:
①Petroleum and its products (see Marine Petroleum Pollution ).
②Metals and acids and alkalis. Including metals such as chromium, manganese, iron, copper, zinc, silver, cadmium, antimony, mercury, and lead, non-metals such as phosphorus and arsenic, as well as acids and alkalis. They directly endanger the survival of marine organisms and affect their use value.
③Pesticides. Mainly brought into the ocean by runoff. Dangerous to marine life.
④Radioactive substances. Mainly from nuclear explosions, nuclear industry or nuclear ship pollution.
⑤Organic waste liquid and domestic sewage. Brought into the ocean by runoff. Extremely serious red tides can be formed.
⑥ Thermal pollution and solid waste. Mainly include industrial cooling water and engineering residues, garbage and dredged mud, etc. After entering the sea, the former can increase the water temperature in local sea areas, reduce the content of dissolved oxygen, affect the metabolism of organisms, and even change the biological community; the latter can destroy the coastal environment and the habitat of marine organisms.
Characteristics
Marine pollution is characterized by multiple sources of pollution, strong continuity, wide spreading range, and difficult to control. The turbidity of seawater caused by marine pollution seriously affects the photosynthesis of marine plants (phytoplankton and seaweed), thereby affecting the productivity of the sea area, and it is also harmful to fish. Toxic substances such as heavy metals and toxic organic compounds accumulate in the sea, and through the enrichment of marine organisms, cause poisoning to marine animals and other animals that feed on them. Oil pollution forms a large oil film on the ocean surface, preventing the oxygen in the air from dissolving into the seawater. At the same time, the decomposition of oil also consumes dissolved oxygen in the water, causing seawater hypoxia, causing harm to marine life, and harming seabirds and humans. . Red tides (a result of seawater eutrophication) caused by aerobic organic matter pollution cause seawater hypoxia and cause marine life to die. Marine pollution can also damage coastal tourism resources. Therefore, marine pollution has attracted more and more attention from the international community.
Due to the particularity of the ocean, marine pollution is different from atmospheric and land-based pollution. Its outstanding characteristics are: First, the source of pollution is wide. Not only human activities in the ocean can pollute the ocean, but also humans on land and other sources. Pollutants produced by activities will also flow into the ocean through river runoff, atmospheric diffusion, rain and snow and other precipitation forms. The second is strong sustainability. The ocean is the lowest-lying area on the earth. It is impossible to transfer or eliminate pollutants through a heavy rain or a flood season like the atmosphere and rivers; once pollutants enter the ocean, it is difficult to transfer them out. Insoluble and difficult to decompose substances accumulate in the ocean, and they are often transmitted through the concentration of organisms and the food chain, posing a potential threat to humans. The third is the wide spread range. The global ocean is an interconnected whole. If a sea area is polluted, it will often spread to the surrounding area, and some of the later effects will even spread to the world. Fourth, prevention and control are difficult and harmful. Marine pollution has a long and accumulation process, which is not easy to detect in time. Once pollution is formed, long-term treatment is needed to eliminate the impact, and treatment costs are high, and the harm caused will affect all aspects, especially the toxic damage to the human body, and it is difficult to completely Clean up.
Pollutant classification
There are many substances that pollute the ocean, and they are divided into waste water, waste residue and waste gas in form. According to the nature and toxicity of pollutants and the ways in which they cause harm to the marine environment, the types of pollutants can be roughly divided into the following categories:
Petroleum and its products
Including crude oil And solvent oil, gasoline, kerosene, diesel, lubricating oil, paraffin, asphalt, etc. fractionated from crude oil, as well as various products formed by cracking and catalysis. About 10 million tons of petroleum pollutants are discharged into the ocean each year, mainly caused by industrial production, including offshore oil well pipeline leaks, tanker accidents, ship pollution, etc., especially in some sudden accidents. The amount of oil leaked can be It is more than 100,000 tons. In this case, a large area of seawater is covered by oil film, which will cause a large number of deaths of marine life, which will seriously affect the value of seafood and other marine activities.
Heavy metals
Including heavy metals such as mercury, copper, zinc, cobalt, chromium, arsenic, sulfur, phosphorus and other non-metals, mercury that enters the ocean by human activities can reach 10,000 tons, which has greatly exceeded the world's annual production record of about 9,000 tons of mercury. This is because coal, oil, etc. will release traces of mercury contained in them during the combustion process, escape into the atmosphere, and eventually return to the ocean. It is estimated that the global mercury polluting the ocean in this respect is about 4,000 tons per year. The annual output of cadmium is about 15,000 tons. According to the survey, the pollution of cadmium to the ocean is much greater than that of mercury.
Acid and alkali
With the development of industry and agriculture, the amount of certain heavy metals and non-metals, as well as acids and alkalis, which enter the ocean through various channels, is increasing. , Has accelerated the pollution of the ocean.
Pesticides
Including large amounts of herbicides and insecticides containing mercury, copper and organic chlorine in agriculture, as well as polychlorinated benzene used in industry. This type of pesticide is very toxic. It enters the ocean through the enrichment of marine organisms, and enters the human body through the food chain, which is more harmful. As a result, more than 100,000 people are poisoned each year. Some new types of cancer are also closely related to this.
Organic substances and nutrient salts
Such substances are complex, including industrially discharged cellulose, furan formaldehyde, and grease; feces, detergents and food residues from domestic sewage, and Residual liquid of chemical fertilizers, etc. These substances enter the ocean and cause the eutrophication of the sea, which can promote the rapid reproduction of certain organisms, consume a large amount of oxygen in the sea, and easily form red tides, which in turn causes the death of a large number of fish, shrimps and shellfish.
Radionuclides
are artificial radioactive substances released by nuclear weapons tests, nuclear industry and nuclear power facilities, mainly strontium-90, cesium-137, etc. The half-life is about 30 years Isotope. It is estimated that the total amount of radioactive substances entering the ocean is 200-600 million Curie. The absolute value of this amount is quite large. Due to the huge ocean water body, the distribution in the seawater is extremely uneven. In the waters with strong radioactivity, the ocean Organisms enter the digestive system through body surface adsorption or through food, and gradually accumulate in organs, and are passed on to humans through the food chain.
Solid waste
Mainly industrial and urban waste, ship waste, engineering muck and dredged materials. It is estimated that the world produces about 10 billion tons of various solid wastes every year, and if 1% enters the ocean, the amount will also reach 100 million tons. These solid wastes seriously damage the aquatic resources in the coastal waters and destroy the coastal landscape.
Waste heat
The thermal waste water discharged by industry causes thermal pollution of the ocean. In some sea areas, if there is hot waste water that is more than 4 degrees Celsius higher than the original normal water temperature, it will Thermal pollution will destroy the ecological balance and reduce dissolved oxygen in the water.
Most of the above-mentioned pollutants are discharged into the ocean from land, and some of them are directly entered from the sea or transported to the ocean through the atmosphere. The distribution of these pollutants in various waters is extremely uneven, and the adverse effects caused are not exactly the same.
Pollution factors
Land-source pollution
Hai, rivers and other channels enter the ocean. The application of chemical pesticides on coastal farmland and dumping and stacking of garbage and wastes on beaches can also cause pollution and damage to the environment.
Ship pollution
For various reasons, ships on board discharge oil or other harmful substances into the ocean. Ship pollution mainly refers to the pollution caused by ships to the surrounding water environment and atmospheric environment in the process of sailing, berthing ports, and loading and unloading goods. The main pollutants are oily sewage, domestic sewage, and ship garbage. In addition, dust will also be generated. Chemicals, waste gas, etc., but generally speaking, have little impact on the environment.
Marine accidents
Ships run aground, hit rocks, collide, oil blowouts and oil pipeline leaks.
Marine dumping
The disposal method of dumping waste into the ocean to reduce the pollution of the terrestrial environment. The act of disposing of wastes or other harmful substances into the ocean through ships, aircraft, platforms or other vehicles. It also includes the abandonment of ships, aircraft, platforms and other floating tools. This is one of the ways that humans use the marine environment to dispose of waste.
Coastal engineering construction
Some coastal engineering constructions have changed the natural properties of coasts, tidal flats, subtidal zones and their subsoil, and disrupted the ecological balance of the ocean and the coastal landscape.
Monitoring
Marine pollution monitoring includes water quality monitoring, bottom quality monitoring, atmospheric monitoring and biological monitoring. Both can be divided into coastal and offshore monitoring and ocean monitoring. The former is densely polluted and complex and changeable, and the monitoring stations set up are dense, and each station is complete and monitored at least once a month; the latter mainly measures those pollutants that have a wide spread, dumped at sea and released into the ocean due to accidents. , The stations are usually set up sparsely, and the number of monitoring times is less. In addition, there is also the use of individual organisms, populations, or communities' responses to pollutants to judge the pollution of the marine environment.
Marine pollution monitoring methods can be divided into conventional monitoring and remote sensing. Routine monitoring refers to on-site manual sampling, observation, indoor chemical analysis and testing, and on-site automatic detection of certain related items. Remote sensing and remote sensing refer to the use of remote sensing technology to monitor the pollution of petroleum, warm drainage and radioactive materials. Its main equipment includes infrared scanners, multi-spectral scanners, microwave radiometers, infrared radiometers, aerial cameras and airborne radars for aerial remote sensing. In addition, there are automatic water quality monitoring buoys operated remotely. Artificial earth satellites have also been widely used for marine pollution monitoring.
Measures
The main measures to prevent marine pollution are: the coordinated development of marine development and environmental protection, based on the treatment of pollution sources; in-depth scientific research on the marine environment; sound environmental protection legal system Strengthen monitoring and management; establish an organization to eliminate pollution at sea; publicity and education; strengthen international cooperation to jointly protect the marine environment.
1. The coordinated development of marine development and environmental protection is based on the treatment of pollution sources;
2. In-depth scientific research on the marine environment;
3, Improve the legal system of environmental protection, strengthen monitoring and management;
4. Establish an organization to eliminate pollution at sea;
5. Vigorously promote education and science
6, Strengthen international cooperation to jointly protect the marine environment.
Hazards
Environmental issues are an intricate complex of problems faced by mankind. It is difficult to clarify them completely in the limited space here. Global atmospheric environmental problems include ecological destruction, environmental pollution and global warming, ozone layer destruction, acid rain, etc. There are other more prominent aspects in environmental issues, such as energy and resource issues, marine pollution issues, transboundary movement of hazardous waste, urban environmental issues, water crisis, biodiversity loss, and so on.
Marine pollution mainly occurs in bays close to the mainland. Due to the dense population and industry, a large amount of wastewater and solid waste are poured into the sea, and the tortuous coasts have caused poor water exchange, which has changed the temperature, pH, salinity, transparency, biological species and quantity of the seawater. The ecological balance of the ocean poses a hazard. Marine pollution is prominently manifested in several aspects such as oil pollution, red tides, accumulation of toxic substances, plastic pollution and nuclear pollution; the most polluted sea areas are the Baltic Sea, the Mediterranean Sea, the Gulf of Tokyo, the Gulf of New York, and the Gulf of Mexico. As far as countries are concerned, Japan, the United States, Western European countries and the countries of the former Soviet Union have serious coastal pollution. my country’s Bohai Bay, Yellow Sea, East China Sea, and South China Sea are also very polluted. Although the concentrations of mercury, cadmium, and lead are generally within the allowable range of the standard, there are some areas that exceed the standard; oil and COD are in various sea areas. There is a phenomenon of exceeding the standard. The Bohai Sea, which is the most polluted, has caused the migration of fishing grounds, the death of fish schools, the flooding of red tides, the desolation of some tidal flat farms, and the loss of some precious marine resources due to pollution.
In the process of human production and life, a large number of pollutants, atomic nuclei, are continuously entering the ocean through various channels, causing varying degrees of harm to marine biological resources, marine development, and marine environmental quality, which will eventually endanger humans. itself.
1. Eutrophication of local water bodies in sea areas;
2. Biological diversity declines sharply from sea areas to land areas;
3. After the death of marine organisms The produced toxins poison the human body through the food chain;
Fourth, destroy the environmental quality of coastal tourist attractions and lose their due value.
Related information
The protection of the ocean is imminent
Marine environmental protection is based on investigations and studies, in response to problems in the marine environment, and based on the balance of marine ecology. It is required to formulate relevant laws and regulations, and use scientific methods and means to adjust the relationship between marine development and environmental ecology, so as to achieve the purpose of sustainable use of marine resources. The marine environment is an important part of the natural environment that humans rely on for survival and development, including marine water bodies, the atmosphere on the seabed and above the sea, as well as coastal and estuary areas that are closely related to the ocean and are affected by the ocean. The problem of marine environment is mainly due to the fact that people did not consider the bearing capacity of the marine environment in the process of developing and using the ocean, and underestimated the reaction of nature, which caused the marine environment to be damaged to varying degrees. The first is the discharge of pollutants into the ocean; the second is the serious impact of certain unreasonable coastal engineering constructions on the marine environment; the third is the cruel fishing of aquatic resources, and the indiscriminate logging of mangroves and coral reefs, which also endangers To ecological balance. The existence of the above problems has posed a serious threat to human production and life