1) Exhaust smoke, exhaust gas, waste water, waste residue and noise emitted from factories;
2) Exhaust smoke, exhaust gas, noise, spoiled water and garbage emitted from people's lives;
3) Exhaust and noise emitted from means of transportation (all fuel-fired vehicles, ships, airplanes, etc.);
4) Heavy use of chemical fertilizers, pesticides, herbicides, and other chemicals run off from irrigated farmland.
5) Waste water and waste residue from mines.
"Two yellow orioles singing in the green willow, a line of egrets on the blue sky", this is the Tang Dynasty poet Du Fu's famous lines in praise of nature. But now some places can no longer see such beautiful scenery due to the harm of environmental pollution. Environmental pollution not only destroys the living environment of living creatures, but also directly threatens the health of human beings.
I. Adverse effects of environmental pollution on living things .
Environmental pollution has a very unfavorable effect on the growth, development and reproduction of organisms, when pollution is serious, organisms in the form of characteristics, survival of the number of obvious changes will occur. Here are four aspects of environmental pollution in acid rain, harmful chemicals, heavy metals and eutrophication of water bodies on the harm to organisms.
1. Acid rain on the biological hazards
Acid rain makes the soil and river acidification, and through the river into the lake, resulting in lake acidification. After the acidification of the lake not only makes the plants growing in the lake and the lake side of the death, and threaten the survival of fish, shrimp and shellfish in the lake, thus destroying the food chain in the lake, and ultimately can make the lake into a "dead lake". Acid rain also directly harms the leaves and buds of terrestrial plants, killing crops and trees.
Now, the harm caused by acid rain is becoming more and more serious, and has become one of the major problems of global environmental pollution. Sulfur dioxide is one of the main pollutants that form acid rain. With the development of the economy, human beings will burn more coal, oil and natural gas, producing more sulfur dioxide and other pollutants, so the harm caused by acid rain is likely to be more serious in the future. China is one of the countries in the world that emit large quantities of sulfur dioxide, and acid rain has already occurred in some areas. For example, in a region in southwest China, four acid rains fell in three months in 1982, and the pH of the rainwater was 3.6 to 4.6, resulting in the victimization of large areas of crops.
As early as the mid-19th century, people noticed that lichens and bryophytes could not survive in cities with severe air pollution, and plant leaves near chimneys tended to show spots of disease. Scientists have found after research that these phenomena are related to atmospheric pollution in the region, and can use some plants to monitor the status of atmospheric pollution in a particular region. Different plants have different degrees of sensitivity to atmospheric pollutants such as sulfur dioxide. For example, when the content of sulfur dioxide in the atmosphere is relatively high, the leaves of alfalfa, sunflower, etc. will quickly fade green, or brown patches appear between the veins of the leaves, and in severe cases, the leaves gradually necrosis. These plants react sensitively to air pollution and can be used to monitor the status of air pollution, called air pollution indicator plants.
2. Harmful chemicals to living things
Pesticides are a common class of harmful chemicals. When people use pesticides to kill germs and pests, they also cause environmental pollution, which is harmful to many kinds of organisms, including humans.
Many pesticides are compounds that are not easily decomposed, and after being absorbed by living organisms, they will continue to accumulate in living organisms, resulting in the content of such harmful substances in living organisms far exceeds the content in the external environment, a phenomenon known as bioconcentration. This phenomenon is called bioconcentration. Bioconcentration is strengthened with the extension of the food chain. For example, a few decades ago, DDT was widely used as a highly effective pesticide to control pests. A place in the United States once used DDT to control tsetse in a lake, so that the lake water residual DDT, while the zooplankton in the body of DDT reached more than 10,000 times the lake water. Small fish eat zooplankton, big fish and eat small fish, resulting in DDT in these big fish in the body of the content of the lake water up to more than eight million times.
3. Heavy metals on the biological hazards of some heavy metals such as Mn, Cu, Zn, etc. is the life of living organisms essential trace elements, but most of the heavy metals, such as Hg, Pb, etc. on the life of living organisms have a toxic effect. Hg, Pb and other heavy metals in the ecological environment can also be concentrated in large quantities in living organisms through bioconcentration, thus producing serious harm
4. The effect of Hg on the life activities of water fleas
Through the demonstration experiments, it can be seen that Hg has a poisonous effect on water fleas. Scientists have found that Hg in nature can be converted into the more toxic methylmercury in the water body through the action of microorganisms. In seawater contaminated with methylmercury, algal plants changed color and marine fish died in large numbers. Scientists also found that a PbCl2 solution with a mass concentration of only 4mg/L can significantly inhibit spinach and tomatoes from photosynthesizing normally. It can be seen, Hg, Pb and other heavy metals for the normal life of biological activities is very harmful.
5. Eutrophication of biological hazards Eutrophication refers to the water body due to excessive content of N, P and other essential plant mineral elements and deterioration of water quality. The water body contains the right amount of N, P and other mineral elements, which is necessary for the growth and development of algae plants. However, if these mineral elements enter the water body in large quantities, they can cause algal plants and other plankton to proliferate. After these organisms die, they are first decomposed by oxygen-demanding microorganisms, which significantly reduces the amount of dissolved oxygen in the water body. Then, the remains of the organisms will be decomposed by anaerobic microorganisms, producing hydrogen sulfide, methane and other toxic substances, resulting in the death of a large number of fish and other aquatic organisms. Slow-moving water bodies such as lakes and bays where eutrophication occurs show blue, red and brown colors depending on the type of plankton. Eutrophication in ponds and lakes is called "hydrophobia", and in seawater it is called "red tide". Industrial wastewater, domestic sewage and water discharged from farmland contain a lot of N, P and other essential plant mineral elements, which are discharged in large quantities into ponds and lakes, causing eutrophication in ponds and lakes. Eutrophication of ponds and lakes not only affects the aquaculture industry, and will make the water contains carcinogenic substances such as nitrite, seriously affecting the safety of human and animal drinking water.
II. Environment and human health
With the increasingly serious environmental pollution, many people breathe polluted air, drinking polluted water, eat from the polluted soil grown out of agricultural products, ringing in the ears of the noise ...... environmental pollution is a serious threat to human health
1. Atmospheric pollution and human health
Atmospheric pollution mainly refers to the chemical pollution of the atmosphere. There are many types of chemical pollutants in the atmosphere, as many as dozens of serious harm to the human body. China's atmospheric pollution belongs to the coal-type pollution, the main pollutants are soot and sulfur dioxide, in addition, there are nitrogen oxides and carbon monoxide and so on. These pollutants mainly enter the human body through the respiratory tract, and are directly transported to the whole body by the blood without the detoxification effect of the liver. Therefore, chemical pollution of the atmosphere is very harmful to human health. This harm can be divided into chronic poisoning, acute poisoning and carcinogenic effects of three.
Chronic poisoning The concentration of chemical pollutants in the atmosphere is generally low, the human body mainly produces chronic toxic effects. Scientific studies have shown that chemical pollution of the urban atmosphere is an important cause of chronic bronchitis, emphysema and bronchial asthma and other diseases. Acute poisoning When factories emit large quantities of harmful gases and there is no wind or fog, the chemical pollutants in the atmosphere are not easy to disperse, which can cause acute poisoning. For example, in 1961, three petrochemical companies in Yokkaichi City, Japan, because of the continuous emission of large quantities of sulfur dioxide and other chemical pollutants, coupled with windless weather, resulting in the occurrence of a large number of local residents asthma. Later, this local air pollution was managed, and the incidence of asthma was reduced.
Carcinogenesis Chemical pollutants in the atmosphere have a carcinogenic effect of polycyclic aromatic hydrocarbons and Pb-containing compounds, including 3,4-benzopyrene, which causes lung cancer in the strongest role. Burning coal, traveling cars and cigarette smoke contain a lot of 3,4-benzopyrene. Chemical pollutants in the atmosphere can also land in water bodies and soil and on crops, after being absorbed and enriched by crops, and then jeopardize human health.
Atmospheric pollution also includes atmospheric biological pollution and atmospheric radioactive pollution. Atmospheric biological pollutants are mainly pathogenic bacteria, mold spores and pollen. Pathogenic bacteria can make people suffer from tuberculosis and other infectious diseases, mold spores and pollen can make some people have allergic reactions. Atmospheric radioactive pollutants, mainly from the atomic energy industry's radioactive waste and medical X-ray sources, etc., these pollutants can easily make people suffer from skin cancer and leukemia.
2. Water pollution and human health
Rivers, lakes and other bodies of water are polluted, will cause serious harm to human health, which is mainly manifested in the following three aspects. First, drinking polluted water and consuming organisms in sewage can make people poisoned and even die. For example, in 1956, some patients of unknown etiology appeared in the Minamata Bay area of Kumamoto Prefecture in Japan. The patients suffered from spasms, paralysis, movement disorders, speech and hearing disorders, and finally died in agony because they could not be treated, and people called this strange disease Minamata Disease. Scientists later studied the disease was caused by local industrial waste water containing Hg. Hg is converted into methylmercury, enriched in the body of fish, shrimp and shellfish, and if people consume these fish, shrimp and shellfish for a long period of time, methylmercury will cause chronic methylmercury poisoning mainly due to brain cell damage. Methylmercury in pregnant women can even cause stunted growth, low intelligence and deformed limbs in affected children. Secondly, water contaminated by human and animal feces and domestic waste can cause viral hepatitis, bacterial dysentery and other infectious diseases, as well as schistosomiasis and other parasitic diseases. Third, some carcinogenic chemicals, such as arsenic (As), chromium (Cr), aniline and other contaminated water bodies, can be suspended in the water body, sediment and aquatic organisms within the accumulation. Long-term consumption of such sewage can easily induce cancer.
3. Solid Waste Pollution and Human Health Solid waste refers to the solid materials discarded by human beings in production and life, such as waste rock from mining, industrial slag, discarded plastic products, and household garbage. It should be recognized that solid waste has no value for use in one process or another and can often be used as a raw material for another production process, hence the term "misplaced raw materials". However, these "raw materials in the wrong place", often containing a variety of substances harmful to human health, if not promptly utilized, long-term accumulation, the more and more, will pollute the ecological environment, harmful to human health.
4. Noise pollution and human health
Noise is harmful to people in many ways: First, damage to hearing. Long-term work in the strong noise, hearing will decline, and even cause noise deafness. Second, interference with sleep. When a person's sleep is disturbed by noise, it can not eliminate fatigue, restore physical strength. Third, induce a variety of diseases. Noise can make people in a tense state, resulting in increased heart rate, blood pressure, and even induce gastrointestinal ulcers and endocrine system dysfunction and other diseases. Fourth, it affects mental health. Noise can make people irritable, unable to concentrate on study and work, and easily lead to work injuries and traffic accidents. Therefore, we should take a variety of measures to prevent and control environmental pollution, so that all living things, including human beings, live in a beautiful ecological environment
Three. The impact of environmental pollution on living things, environmental pollution and the "three effects"
Environmental pollution often has the human or mammalian carcinogenic, mutagenic and teratogenic effects, collectively known as the "three effects". It takes a long time for the harmful effects of the "triple effect" to show up, and some of them even affect future generations.
1. Carcinogenic
Carcinogenic refers to the role of human or mammalian cancer. As early as 1775, the British doctor Porter found that chimney sweeps are prone to scrotal cancer, and he believed that scrotal cancer is related to frequent exposure to coal soot. 1915, Japanese scientists through experiments to confirm that coal tar can induce skin cancer. Pollutants that can induce cancer in humans or mammals are called carcinogens. Carcinogens can be divided into three categories: chemical carcinogens (e.g., nitrites, asbestos, and dichloromethyl ether used in the production of mosquito coils), physical carcinogens (e.g., radium fusion products), and biological carcinogens (e.g., aflatoxins).
2. Mutagenicity Mutagenicity refers to the effect of causing gene mutation, chromosome structure variation or chromosome number variation in humans or mammals. Mutations in human or mammalian germ cells can affect the process of pregnancy, leading to infertility or early embryonic death. Mutations in human or mammalian somatic cells can lead to the development of cancer. Common mutagens include nitrosamines, formaldehyde, benzene and dichlorvos.
3. Teratogenesis Teratogenesis refers to the role of the mother in pregnancy, interfering with the normal development of the embryo, resulting in newborns or young mammals congenital malformations of the role of the early 1960s, Western Europe and Japan appeared a number of deformed newborns. Scientists found that the original pregnant women in the 30 days to 50 days after pregnancy, taking a called "reaction stop" sedative drugs, this drug has a teratogenic effect. Currently recognized teratogens include methylmercury and certain viruses.
In summary, the harm of environmental pollution is huge, involving a wide range, the degree of harm, invasive and difficult to manage. We must do a good job at every step to prevent environmental pollution, adhere to the prevention-oriented, prevention combined with the principle of comprehensive management, the real environmental protection and governance with the economy, social and sustainable development and coordination.