1. Environmental impact
Environment refers to the things around people. 1The Environmental Protection Law of People's Republic of China (PRC), published on February 26th, 989, clearly stipulates: "The environment mentioned in this law refers to the sum total of various natural and artificially transformed natural factors that affect human survival and development, including atmosphere, water, ocean, land, mineral deposits, forests, grasslands, wild animals, natural relics and cultural relics.
2. Environmental classification
Environment can be divided into natural environment and artificial environment.
The natural environment consists of living organisms and inorganic organisms (atmosphere, ocean, rocks, water, soil, etc. ) directly or indirectly affecting human life and production.
The artificial environment is a variety of things formed by human activities. It includes man-made material, energy and spiritual products, as well as interpersonal relationships formed in human activities. This kind of activity is what distinguishes human beings from animals. Such as: the cultivation and domestication of animals and plants, artificial forests, green grasslands, houses, cities, vehicles, factories, entertainment places and so on.
(2) Environmental problems and their classification
1. Environmental problems
Environmental problems refer to changes that are not conducive to human beings due to natural and human activities.
2. Classification of environmental problems
Environmental problems can be divided into two categories. The first category is the environmental pollution caused by excessive pollutants discharged into the environment by industrial and agricultural production and human life; The second category is the ecological effect caused by people's unreasonable development and utilization of resources and destruction of natural ecology. These two environmental problems often exist at the same time, but in some areas, one environmental problem may be the main one.
At present, the international community is most concerned about population, resources, ecological destruction, environmental pollution and other environmental issues that have a significant impact on human production and life.
(1) water pollution
Water is the material basis on which human beings and all living things depend, and has the closest relationship with human beings, so it has economic utilization value. With the rapid growth of the world population and the development of industrial and agricultural production, the consumption of water resources is increasing, and the world water consumption is increasing at a rate of 3% ~ 5% every year. At present, 43 countries and regions in the world are short of water, accounting for 60% of the global land area. About 2 billion people are short of water, and 654.38 billion people have no good drinking water.
In addition to the influence of natural conditions, water pollution destroys water resources and is one of the important reasons for water crisis. Water pollution means that the harmful substances entering the water body exceed the self-purification ability of the water body and destroy the ecological balance of the water body. At present, more than 4,200×108m3 of sewage is discharged into rivers, lakes and seas every year, and 5,500×108m3 of fresh water is polluted, accounting for more than 14% of global runoff. It is predicted that the global sewage volume will increase by 14 times in the next 30 years. Especially in the third world countries, the situation that sewage and wastewater are discharged into water bodies without treatment is more serious, which has caused the phenomenon that some areas in the world have water but are seriously short of water. The shortage of water resources has become an obstacle to the economic development of many countries and a common concern of the whole world. At present, water resources are facing the double contradiction of water shortage and continuous growth of water consumption. As the United Nations warned in 1977, "water will soon become a serious social crisis, and the next crisis after the oil crisis is water."
(2) Air pollution
The atmosphere is a mixture of many gases, which can be divided into constant, variable and uncertain components according to their composition types. The constant components of the atmosphere refer to N2, O2, Ar and trace rare gases such as Ne, he, Kr and Xe, among which three components * * * of N, O and Ar account for 99.96% of the total volume of the atmosphere. The variable components are CO2 and water vapor in the atmosphere, and the contents of these gases are influenced by factors such as region, season, meteorology, human life and production activities. Uncertain components are produced by natural and human activities. Dust, sulfur, hydrogen sulfide, sulfur oxides, carbon oxides and malodorous gases produced by natural volcanic eruptions, forest fires, tsunamis, earthquakes and other temporary disasters enter the atmosphere, as well as waste gas discharged from human social activities, transportation and industrial and agricultural production, which makes the concentration of substances without components or some components in the clean atmosphere exceed the normal atmospheric content, causing harm to people's life, work, health, mental state, equipment and property and ecological environment.
Air pollution has become a serious environmental problem. According to incomplete statistics, the global atmosphere is polluted by more than 7× 108t kinds of harmful substances every year. Among the seven main harmful substances, particulate matter accounts for about 15%, SO2 accounts for about 22%, CO accounts for about 40%, NO2 accounts for about 8%, carbon oxide accounts for about 14%, and H2S and NH3 account for about 65,434. At present, global environmental problems caused by air pollution, including greenhouse effect, acid rain and ozone layer destruction, have aroused widespread concern.
1) acid rain. Acid rain refers to precipitation (such as rain, fog, dew, hail, etc. ) is formed by rain and snow with pH less than 5.6, which is a phenomenon of air pollution. The pH value of rainwater decreases due to the artificial discharge of acidic substances such as SO2 and NO2 into the atmosphere. When the pH value is lower than 5.6, acid rain will appear. All kinds of acids formed by different acidic substances in the atmosphere have effects on the formation of acid rain, but their contributions are different. Generally speaking, sulfuric acid accounts for 60% ~ 70%, nitric acid accounts for 30%, hydrochloric acid accounts for 5% and organic acid accounts for 2%. Therefore, SO2 and NO2 emitted by human beings are the two main substances that form acid rain. The harm of acid rain is mainly to destroy forest ecosystem, change soil properties and structure, destroy aquatic ecosystem, corrode buildings and damage human respiratory system and skin. When acid rain falls to the ground, the water quality will deteriorate and all kinds of aquatic animals and plants will be threatened by death. The leaves and roots of plants absorb a lot of acidic substances, which leads to withering and death. After acid rain enters the soil, the soil fertility is weakened. Humans have been living in acid rain for a long time, and drinking acidic water can cause a series of diseases such as respiratory organs, kidney diseases and cancer. The harm of acid rain is relatively common, and the problem of acid rain is not only a regional environmental pollution problem, but sometimes even regarded as a global environmental problem. During 1998, the annual precipitation pH of 52.8% cities in China was lower than 5.6, and that of 73.03% cities in the south was lower than 5.6. The cities with precipitation pH lower than 4.5 were Zhuzhou, Yiyang, Shaoguan, Qingyuan, Nanchang, yingtan and Changsha. The annual average precipitation pH value of Tumen, Qingdao, Xi and Tongchuan in northern cities is lower than 5.6.
2) Greenhouse effect. Due to the increase of water vapor and CO2 in the air near the ground, the absorption of long-wave radiation on the ground is increased, which leads to the formation of an insulating layer between the ground and the atmosphere, so that the heat near the ground can be maintained. This phenomenon that causes the global temperature to rise is called the greenhouse effect. Gases that can cause the greenhouse effect are called greenhouse gases. Greenhouse effect can be divided into natural greenhouse effect and man-made greenhouse effect. The greenhouse effect caused by natural factors is called natural greenhouse effect, and it is called artificial greenhouse effect because of the large use of chemical fuels, high industrial development and deforestation destroying the natural heat balance. Usually the greenhouse effect refers to the latter, also known as global warming. It is found that there are about 30 kinds of gases that can produce greenhouse effect in the atmosphere at present, of which CO2 contributes about 66%, CH4 16% and CFCs 12%, indicating that CO2 is the most important gas that causes greenhouse effect. In the first climate change assessment report of 1990, the United Nations Intergovernmental Panel on Climate Change (IPCC) pointed out that in the past 100, the global average surface temperature increased by 0.3 ~ 0.6℃. The analysis of about 1× 108 data and 6000× 104 ocean observation data from more than 2000 land observation stations in the UK shows that 198 1 ~ 1990 is the global average temperature ratio/kloc-0. It is predicted that by the middle of 2 1 century, the overall pattern of world energy consumption will not change fundamentally, and mankind will continue to use fossil fuels as the main energy source, and the demand for energy will increase. It is predicted that the global population will reach about 9 billion in the middle of 2 1 century, the volume fraction of CO2 in the atmosphere will be above 560× 10-6, the earth temperature will rise by 0.3℃ every 10 year, and the global average sea level will rise by 6 cm every 10 year. The global disaster area can reach 500× 104km2, accounting for 3% of the global land area, which will threaten the survival of 654.38 billion people.
3) hole in ozone layer. Ozone (O3) is a trace gas component in the air. It is estimated that if all ozone from the earth's surface to a height of 60km is concentrated on the earth's surface, it is only 3mm thick and the total mass is about 30× 108t. The ozone in the air is mainly concentrated in the stratosphere, forming an ozone layer 20 ~ 30 km away from the ground. The ozone layer plays a very important role in protecting the ecological environment. It has a strong ultraviolet absorption function and is a filter for solar radiation. The total absorption rate of ozone to ultraviolet rays is 70% ~ 90%. So ozone can protect all living things and human beings on the earth from ultraviolet rays. Because of human activities, the ozone layer is damaged and thinned, which leads to the depletion of the ozone layer, the so-called "ozone hole". In the early 1970s, American environmental scientists first observed that the ozone layer was damaged. 1985, British scientists confirmed that there was a "hole" in the ozone layer over Antarctica, that is, the ozone layer was destroyed and became very thin. By 1994, the ozone layer over Antarctica was destroyed by 2400× 104km2. The ozone layer over Antarctica was formed 2 billion years ago, but it was destroyed by 60% in a century of the 20th century. The ozone layer over the northern hemisphere is thinner than ever; The ozone layer in Europe and North America decreased by 10% ~ 15% on average. Siberia is reduced by 35%. The serious consequences caused by destroying the ozone layer are: ① endangering human health and increasing diseases such as sunburn, keratitis, skin cancer and immune system. According to UNEP 1986, if the total ozone is reduced by 1%, the canceration rate of skin will increase by 4%, that of flat cells will increase by 6%, and that of cataract patients will increase by 0.2% ~ 0.6%. (2) Destroy the ecosystem, affect the photosynthesis of plants, and lead to crop yield reduction. Ultraviolet rays can also cause mutations in some biological species. Experiments show that two-thirds of 200 plants are damaged after artificial ultraviolet irradiation of 280 ~ 320 nm. If the ozone in the air decreases by 10%, the abnormal rate of many aquatic organisms will increase by 18%, and the photosynthesis of phytoplankton will decrease by 5%. ③ Too much ultraviolet radiation will make plastics and polymer materials easy to age and decompose.
(3) Soil pollution
Soil pollution refers to the waste generated in people's production and life entering the soil. When the dosage exceeds the self-purification ability of soil, the soil is polluted, which affects the normal growth and development of plants, leads to the accumulation of harmful substances in plants, reduces crop yield and quality, and finally affects human health. Using industrial wastewater and municipal sewage for irrigation, piling up waste residue and solid waste, and applying a lot of chemical fertilizers and pesticides may pollute the soil.
(4) deterioration of ecological environment
The deterioration of global ecological environment, broadly speaking, includes the contradiction between population, food and resources; From the environmental point of view, it mainly includes forest reduction, land degradation, soil erosion, desertification, species disappearance and many other aspects.
Land degradation is one of the most serious ecological and environmental problems in contemporary times, which is weakening the foundation of human survival and development. The root causes of land degradation are population growth, expansion and intensification of agricultural production, overgrazing and man-made destruction of vegetation, leading to soil erosion, desertification, land impoverishment and land salinization.
Soil erosion is a common ecological and environmental problem in the world today. According to the latest estimate, the existing soil erosion area in the world is 2500× 104km2, accounting for 16.8% of the global land area, and the annual loss is as high as 257× 108t, which is several times higher than the world soil regeneration rate. The world loses 600×104 ~ 700×104km2 of land every year, and 80% of the population affected by soil erosion is in developing countries.
Land desertification refers to the degradation process of desert landscape environment characterized by sandstorm activity and sand dune fluctuation in non-desert areas. At present, there are 36×108hm ~ 2 arid land directly endangered by desertification in the world, accounting for 70% of the global arid land. The expansion of desertification has reduced the available land area, land yield and the ability to raise people. Desertification is also very serious in China. About 65.438+0.7 billion people in China are harmed and threatened by desertification, and the annual economic loss caused by desertification is about 2-3 billion dollars.
The disappearance of biological species is a major ecological and environmental issue of global concern. Endangerment and extinction of species have been developing, and the more modern, the faster the extinction of species. It is roughly estimated that from 8000 BC to 1975, the average extinction rate of mammals and birds increased by about 1000 times. Biologists warn that if deforestation, desertification and wetland destruction continue to develop at the current rate, 654.38 million +0 billion biological species will disappear from the earth forever by 2025.
(3) Environmental science
With the emergence of environmental problems, people began to pay attention to environmental problems. Environmental science takes the contradiction between man and environment as the research object, and environmental science is a marginal subject composed of a huge system from multidisciplinary to interdisciplinary. Its main tasks are: to reveal the unity of opposites between human activities and natural ecology; Explore the law of environmental evolution on a global scale; Explore the impact of environmental changes on human survival; Study the technical measures and management measures for comprehensive prevention and control of regional environmental pollution.
At present, environmental science mainly uses the theories, techniques and methods of natural science and social science to study environmental problems, and has formed many branches related to it.
Natural science includes environmental engineering, environmental geoscience, environmental biology, environmental chemistry, environmental physics, environmental mathematics, environmental water conservancy, environmental system engineering, environmental medicine and so on.
Belonging to social sciences are: environmental sociology, environmental economics, environmental law, environmental management, etc.
Environmental engineering refers to using the principles and methods of engineering technology to prevent and control environmental pollution, rationally utilize natural resources, and protect and improve environmental quality. The main research contents include air pollution prevention and control engineering, water pollution prevention and control engineering, solid waste treatment and recycling, noise control and so on. At the same time, the comprehensive prevention and control of environmental pollution is studied, and the best solution to environmental problems is sought from the whole regional environment by using the methods of system analysis and system engineering. Geological exploration and drilling environmental engineering belong to a branch of environmental engineering.