At present, China's marine environment, in general, basically still in a good state. But in some coastal bays, estuaries and local waters, such as Dalian Bay, Liaohekou, Jinzhou Bay, Bohai Bay, Laizhou Bay and Jiaozhou Bay, environmental pollution is more serious; some marine aquatic resources decline, catch reduction, a few valuable seafood damage, some marine aquatic resources quality is affected; some of the shoals are deserted, the coastal environment has been damaged. As far as the sea area is concerned, the Bohai Sea coast is more seriously polluted, followed by the East China Sea and the Yellow Sea, and the South China Sea is less polluted.
Currently, pollution and damage to China's marine environment are mainly the following factors:
1, land-based pollutants: according to the relevant departments of statistics, China's coastal areas, the annual discharge into the sea of industrial sewage and domestic sewage of about 6 billion tons. In the domestic sewage, the East China Sea coast of the largest emissions, followed by the South China Sea coast and the Bohai Sea coast, the Yellow Sea coast is the smallest, in the industrial sewage, but also to the East China Sea coast of the largest emissions, accounting for 50% of the total amount; Bohai Sea coast and the South China Sea coast, followed by the Yellow Sea coast is the least.
2, the pollutants discharged from ships: China has more than 100,000 motorized vessels, tens of thousands of foreign ships entering our ports and sailing through the waters under our jurisdiction each year, there are a large number of oily sewage discharged into the sea. For example, in 1979, Brazilian tankers operating in Qingdao oil terminal, a run of 380 tons of oil.
3, the pollution of marine oil exploration and development: China's coastal distribution of several large oilfields and a dozen petrochemical enterprises, running, venting, dripping, leaking oil quantity is very considerable, more than 10 million tons of oil into the sea each year.
4, artificial dumping of waste pollution: in the past the ocean as a big "dumpster", arbitrary dumping of waste. Such as Dalian incense burner reef coast, Huludao, Qingdao, Wenzhou, Zhanjiang and other places, the garbage, slag and other wastes piled up in the sea or directly into the sea.
5, the construction of unreasonable marine engineering and marine development: this makes some deep-water harbors and channels silted up, the ecological balance of the local sea was destroyed.
China's coastal pollution sources of various types are mainly more than 200, Bohai, Yellow Sea coast has more than 100, the East and South China Sea coast about 100. These sources of pollution discharged into the sea of important pollutants
Substances, there are petroleum hydrocarbons, heavy metal pollutants and organic pollutants. Carried by rivers, is the main pathway for pollutants into the sea.
Two, the current situation of soil pollution in China
1, heavy metal pollution of soil
With the intensification of industrial and urban pollution and the increase in the types and quantities of agricultural chemicals, soil heavy metal pollution is becoming more and more serious, and the degree of contamination is worsening, and the area is expanding year by year. Heavy metal pollutants move poorly in the soil, stay for a long time, cannot be degraded by microorganisms, and can ultimately affect human health through water, plants and other media.
According to the national survey of sewage irrigation areas conducted by China's Ministry of Agriculture, in about 1.4 million hm2 of sewage irrigation areas, the area of land contaminated by heavy metals accounted for 64.8% of the area of sewage irrigation areas, of which 46.7% were mildly contaminated, 9.7% were moderately contaminated, and 8.4% were severely contaminated. China's annual production of more than 10 million tons of grain is reduced due to heavy metal pollution, and as much as 12 million tons of grain contaminated by heavy metals each year, with a combined economic loss of at least 20 billion yuan.
From the current heavy metal pollution survey, most of China's urban peri-urban soils have suffered varying degrees of pollution. Our recent survey data show that a hilly area in Jiangsu Province 14000km2 range, copper, mercury, lead and cadmium pollution area of 35.9%. Soil survey results of the Guangdong Provincial Geological Survey Department showed that 10,000km2 of land in the Xijiang River Basin suffered heavy metal contamination of an area of 5,500km2, the rate of contamination of more than 50%, of which, mercury contamination of an area of 1,257km2, the depth of contamination reaches the ground floor 40cm.
2, organic pollution of the soil
At present, China's organic pollution of soils is very serious and the impact of agricultural products and human health has begun to be recognized. Agricultural products and human health effects have begun to show. For example, from 1959 in China in the middle and lower reaches of the Yangtze River with sodium pentachlorophenate to combat schistosomiasis, which impurity dioxin has caused regional dioxin-type pollution, Dongting Lake, Poyang Lake, high levels of dioxin in the mud. Organochlorine pesticides have been banned for nearly 20 years, and the residues in soil have been greatly reduced, but the detection rate is still very high. The detection rate of hexachlorobenzene in vegetable soil in Guangzhou is 99%, and the detection rate of DDT is 100%. The detection rate of hexachloroethylene and DDT in farmland soil in the Taihu Lake basin is still 100%, and the highest residue level in some areas is still above 1mg/kg. At the same time, with the acceleration of urbanization and industrialization, soil organic pollution near cities and industrial areas is increasing. Nanjing Soil Research Institute of the Chinese Academy of Sciences recently conducted a survey of agricultural soil around an iron and steel group and soil near industrial zones, the results show that the average value of the total of 15 kinds of polycyclic aromatic hydrocarbons (PAHs) in agricultural soil is 4.3mg/kg, and mainly to more than 4 rings of carcinogenic pollutants are mainly accounted for the total amount of about 85%, only 6% of the sampling points are still in the safe level. Soil pollution near industrial areas is much higher than that of agricultural soil: PCBs, PAHs, plastic plasticizers, herbicides, butachlor, etc. These highly carcinogenic substances can be easily detected in the soil around the heavy industrial areas and exceed the national standard many times. The results of the investigation of 10 PAHs in the soil of urban and suburban areas of Tianjin show that the urban area is the area with the most serious exceedance of soil PAHs content, in which the exceedance of dicyclonaphthalene is the most serious, and the exceedance of benzo(a)pyrene, which is a strong carcinogen, is not optimistic either. In Tibet, China, the PCB content in soil not directly contaminated is 0.625-3.501g/kg, while its content detected in Shenyang city is 6-151g/kg.
3. Enrichment of organic pollutants in living organisms
Because soil is the nutritional source of plants and some organisms, organic pollutants in soil will be transferred and migrated through the food chain. migration, and currently animals and humans themselves suffer from the pollution and threat of organic pollutants.
In the process of transferring and migrating organic pollutants along the food chain, the content increases step by step, and its enrichment factor in each trophic level can reach an alarming degree. The production of hexachloroethylene and DDT as high-residue-rate pesticides was stopped in 1983, and over time, the residues of these two highly toxic pesticides have become almost undetectable in the soil, but the content detected in fish is nearly 100 times higher than that in the soil, and in the eggs of the night heron and the egret, this content is amplified by 100 to 200 times. For example, the results of bird biomonitoring in Lake Taihu show that hexachlorobenzene (HCB) was not detected in the silt at the bottom of Lake Taihu, and DDT was 3.4 ng/g, and through fish bio-enrichment, HCB reached 28.5 ng/g, DDT reached 270.7 ng/g, and when it eventually reached the eggs of night herons and egrets, HCB could be as high as 460.0 ng/g, and DDT could be as high as 5,626.7 ng/g. In addition, toxic organic pollutants are passing through the food chain and being detected in the soil nearly 100 times higher than in the soil, and this level is amplified 100 to 200 times. Toxic organic pollutants are endangering human health through the food chain, and these organic pollutants are stored in the human body for long periods of time and can be indirectly transferred to newborns through breastfeeding or directly acquired by the fetus through the placenta.
4, soil radioactive contamination
In recent years, with the wide application of nuclear technology in various fields such as industry and agriculture, medical, geological, scientific research, more and more radioactive pollutants into the soil, these radioactive pollutants in addition to direct harm to the human body, but also through the biological chain and the food chain into the human body, in the body to produce internal irradiation, damage to the human body tissues and cells, causing tumors, leukemia and genetic disorders and other diseases. As shown in scientific research, the radiation hazard of radon daughters accounts for more than 55% of all radiation hazards suffered by the human body, and most of the latent period of induced lung cancer is more than 15 years, and there are about 50,000 cases of radon cancer in China every year, while 23.7% of the public lung cancers in urban areas of Tianjin are caused by radon and its daughters.
Three, China's air pollution status
In recent years, although China's air pollution prevention and control work has achieved great results, but due to a variety of reasons, China's atmospheric environment is still facing a very serious situation. The total amount of air pollutant emissions remain high. Now, the country's annual emissions of sulfur dioxide up to 18.57 million tons, 11.59 million tons of soot, industrial dust 11.75 million tons, air pollution is still very serious. The quality of the atmospheric environment in most of the country's cities exceeds the standards set by the State. Of the 47 key cities in the country, more than 70% of them have an atmospheric environmental quality that fails to meet the national secondary standards; of the 338 cities participating in the environmental statistics, the air environmental quality of 137 cities exceeds the national tertiary standards, accounting for 40% of the cities in the statistics, and they are seriously polluted cities. Pollution in acid rain areas is becoming increasingly prominent. Acid rain area from the 80's in the southwest of the local development to the present southwest, south China, central and east China, four large areas of acid rain area, acid rain covers an area of more than 30% of the national territory, China has become the world's third largest after Europe, North America, the heavy acid rain area. Changde city acid rain pollution is also very serious, in 1996 the frequency of acid rain reached 100%, every rain must be acid. By taking the establishment of the city's atmospheric environmental protection circle. Closure of Chengzheng brick factory, the removal of serious pollution of small boilers and other measures, the atmosphere of soot and sulfur dioxide pollution has been reduced, the frequency of acid rain has declined, but is still as high as 41.6%.
According to the budget, the first half of the early 21st century, China's energy development, utilization and consumption will have a relatively large increase, and the characteristics of China's energy resources and the level of economic development, determines the energy structure of coal-based energy structure will be there for a long time. Therefore, the control of soot-type air pollution will be long-term as the main task in the field of air pollution control in China.
Three, China's water pollution status quo and effective solutions
Reform and opening up more than twenty years, China's rapid economic development, but environmental pollution is becoming increasingly serious, especially the pollution of drinking water is particularly prominent. The current insecurity of living drinking water is mainly reflected in:
1. Agricultural pollutants include livestock manure, pesticides, fertilizers and so on. In agricultural sewage, one is the high content of organic matter, plant nutrients and pathogenic microorganisms, and the second is the high content of pesticides and fertilizers. According to relevant information, on 100 million hectares of arable land and 2.2 million hectares of grassland, 1.10449 million tons of pesticides are used annually. China is one of the world's most serious soil erosion, annual topsoil loss of about 5 billion tons, resulting in a large number of pesticides, fertilizers with the topsoil into the rivers, rivers, lakes and reservoirs, with the loss of nitrogen, phosphorus, potassium nutrients, so that 2/3 of the lakes are subjected to varying degrees of eutrophication of the pollution hazards, resulting in the abnormal reproduction of algae and other living organisms, causing the transparency of the water column and the change in dissolved oxygen, thus leading to deterioration of water quality.
2. Life pollution sources are mainly urban life in the use of various detergents and sewage, garbage, feces, etc., mostly non-toxic inorganic salts. Domestic sewage contains nitrogen, phosphorus, sulfur, more disease-causing bacteria. According to survey statistics, in 1998 China's domestic sewage discharge 18.4 billion tons.
3. Industrial pollution, China's annual industrial wastewater and more than 90% of untreated sewage discharged into the waters. The country has monitored more than 1,200 rivers, more than 850 are currently polluted, more than 90% of urban waters are also polluted, resulting in many sections of the river fish and shrimp extinct, in line with the national level and the second level of water quality standards of the river accounted for only 32.2%. Pollution is developing from shallow to deep, groundwater and near-sea water are also being polluted, and the amount of water we can drink and use is decreasing without us realizing it. The world's number one killer of water pollution is increasing, has constituted a major threat to the survival and safety of mankind, and has become a major obstacle to human health, economic and social sustainable development. According to the world authority survey, in developing countries, 8% of all kinds of diseases are spread because of drinking unhygienic water, and at least 20 million people die globally every year because of drinking unhygienic water. Therefore, water pollution is known as the "world's number one killer".
China has 82% of the people drinking shallow wells and rivers, where water quality is seriously polluted, bacterial contamination exceeds the health standard of 75%, by the serious contamination of organic matter in the drinking water of the population of about 1.6 billion. For a long time, people have thought that tap water is safe and hygienic. However, because of water pollution, today's tap water can not be considered safe and sanitary. A survey shows that in the world's tap water, measured chemical pollutants are as many as 2221, some of which are recognized as carcinogens or carcinogens. From the tap water drinking standards, our country is still at a low level, the water plant can only use sedimentation, filtration, chlorination and disinfection methods, river water or groundwater into a simple processing of potable water. Chlorination of tap water can effectively kill germs, but also produces more halogenated hydrocarbon compounds, these chlorine-containing organics content has increased exponentially, is the cause of human suffering from a variety of gastrointestinal cancer is the biggest root cause. At present, the composition of urban pollution is very complex, polluted waters in addition to heavy metals, but also contains a lot of pesticides, fertilizers, detergents and other harmful residues, even if the tap water is boiled, the above residues are still driven away, and the boiling water increases the concentration of hazardous substances, reduces the amount of dissolved oxygen that is beneficial to human health, and also nitrite and chloroform, and other carcinogens to increase, so drinking boiled water is also not a high safety factor. Therefore, the safety factor of drinking boiled water is not high. According to the latest information, only 23% of the residents of China's major cities drinking water in line with health standards, small towns and rural drinking water qualification rate is even lower. Water pollution prevention and control of urgent need to ensure that drinking water is qualified. To this end, should increase water pollution monitoring efforts, the establishment of water supply source protection zone.
People have realized that we can not destroy the ecological environment to develop the economy, the cost is too great. China has put forward the strategy of sustainable socio-economic development and protection of people's health, to rectify the pollution of the waters to take a series of strong measures. We must not go back to the old road of pollution after treatment, in order to human health and survival, in order to have a clean water environment, protect water resources, when from now on!