Тяжелые металлы как фактор загрязнения окружающей среды (например) Реферат

Free air is the most important life-sustaining natural environment and it’s a mixture of gases and aerosols of surface layer of the atmosphere. The results of different ecological researches uniquely attest that the pollution of this atmosphere surface layer is the most powerful, constantly affecting factor of effects on people, food chain and environment. Free air has unlimited capacity and plays the role of the most mobile, chemically aggressive and all-pervading agent of interaction near the surface components of biosphere, hydrosphere and lithosphere. It’s also known that for the retention of biosphere the ozone layer plays a huge role. It absorbs the harmful ultraviolet radiation of the Sun. The ozone layer also builds a temperature barrier, which protects the earth’s surface fr om the cooling.

The atmosphere affects intensively not only on people and biota, but also on hydrosphere, land cover, geological environment, buildings and other man-made objects. That’s why protection of free air and ozone layer is the most prioritized problem in ecology and that’s why it attracts attention in all developed countries.

Contaminated free air leads to cancer of lungs, throat and skin, central nervous system disorder, allergic and respiratory diseases, defects in newborns and many other diseases. The list of these diseases is defined by present in the air contaminants and by their combined effect on the human organism. The results of many researches showed that there’s a close connection between the human health and the quality of free air.

The negative effect of contaminated atmosphere on the land cover is related to the loss of acid precipitation, which washes out of the soil calcium, humus and macro elements, and it’s also related to violation of the photosynthesis process, which lead to growth retardation and death of plants.

The acid precipitations are a powerful factor not only for weathering of rocks and quality deterioration of bearing soils, but also a factor of chemical destruction man-made objects, including cultural monuments and landlines. The programs for solving the problem of acid precipitations are realized today in many economically developed countries.

Process and sources of surface atmosphere contamination are numerous and various. Originally they are divided in anthropogenic and natural. Among anthropogenic reasons there are fuel combustion and waste incineration, nuclear reactions during the obtaining nuclear energy, the testing of nuclear weapon, metallurgy and hot metalworking, different chemical industries, including oil and gas processing, coal processing.

During the fuel combustion the most intensive contamination is in mega polices and huge cities, industry centers because of many cars, heat electric stations, boilers and other power facilities, which work on masut, coal, diesel fuel, natural gas and petrol.

Contribution of automobile transportation to general pollution of free air reaches 40-50%. Accidents on nuclear power plants and testing of nuclear weapon are powerful and extremely dangerous factors of air pollution. It’s connected to

Water is the most important life-supporting natural environ, which formed through the Earth’s evolution. Water is the composite part of biosphere and it has many abnormal characteristics that effect on physical, chemical and biological process. Among these characteristics are heat capacity, evaporation, surface tension, dissolution, dielectric permeability and transparency. Except this water is also characterized by high migratory capacity, which plays a big role for the interaction of water and contiguous natural areas. Said water properties define the potential opportunity to accumulate many contaminants and pathogenic microorganisms in it. In connection with constantly increasing contamination of surface water, the groundwater becomes the almost only resource for drinking water supply of mankind. That’s why their protection of pollution and exhaustion and rational using has a strategic value.

The situation is exacerbated because of the useful for drinking groundwater is situated in the uppermost area of artesian basin and other hydrogeological structures, and lakes and rivers make only 0,019% of the common water volume. The water of high quality is important not only ford and other daily living needs, but also for some industrial sectors. The danger of groundwater pollution is that the earth hydrosphere (especially artesian basins) are the finite tank of contaminants accumulation, which has both surface and deep origin. The pollution of undrained land water is mostly long-term and irreversible. The most dangerous is the contamination of drinking water by microorganisms, which are pathogenic and can lead to different disease outbreaks among the people and animals. It’s proved that the main reason of epidemics is using of contaminated with viruses and microbes water.

The most often reasons of water pollution are industrial and agricultural drains, and dropping out of anthropogenic activity products through the precipitation. These processes contaminate not only the surface water, but also the groundwater, the world ocean.

Accidents at the oil tankers or pipelines are also an essential factor of water ecological environment deterioration. In the last years such accidents happen more often.

Nowadays the problem of water pollution by nitrogen compounds is getting more actual. The surface- and groundwater are characterized by high concentrations of nitrates and nitrites. The similar situation is by water pollution of organic substances. It’s due to the fact that the ground hydrosphere is not able to oxidize such big masses of organic substances, which receive there. As a result of this is the irreversibility of hydro systems pollution.

It’s known that the land today makes 1/6 part of the whole planet, wh ere live people. That’s why the protection of lithosphere is very important. The soil protection is the most important task for humans, because any unhealthy compounds, which are in the soil, early or later get to the human’s organism.

Firstly, contaminants are standing getting to the open ponds and groundwater, which can be used for drinking and other needs. Secondly, these contaminations from groundwater and open ponds get to animals and plants organisms and the through the food chain they get human’s organism. Thirdly, many harmful compounds can accumulate in biological tissues and first of all in bones. According to the experts evaluations the biosphere gets every year about 20-30 billons tons of solid wastes, 50-60% of them are organic compounds and about 1 billion tons are acidic agents of gas or aerosol character. All there contaminants have different ways to get in the soil.

Different kinds of soil pollution, most of them are anthropogenic, can be divided by sources of their coming to the soil. Now we describe them.

Precipitation: many chemical compounds that get to the atmosphere through the work of different industries, dissolve after that in the drops of atmospheric moisture and through the precipitation they get to the soil.

Dust and aerosols: solid and liquid compounds by the dry weather settle usually in the form of dust and aerosols, during the direct soil absorption of gaseous compounds. Different harmful compounds are absorbed by leaves with stomas, and then when the leaves fell, all these compounds get to the soil.

It’s not easy to classify the ways of soil contamination, but if to say in common, we can speak about such contaminants of soil: wastes, litter, heavy metals, pesticides, radioactive substances.

Solid household wastes are very dangerous and different in their composition: food waste, paper, scrap-metal, rubber, glass, wood and textile, synthetic and other things. Food wastes attract birds, rodents, big animals, which corpses are sources for different bacteria and viruses. Precipitations, sun radiation and heat allocation in connection with fires contribute unpredictable physical, chemical and biological process on household landfills, which products are numerous toxic chemical compounds in liquid, solid and gaseous condition. The most important biogenic effect of household wastes is that the wastes are favorable for breeding of insects, birds, rodents, other mammals and microorganisms. Herewith birds and insects are peddlers of morbific bacteria and viruses for the long distances.

Wastewater is not less dangerous. Despite the building of cleaning installations and other measures, decrease of negative effect of such water on environment is an important problem for all urbanized areas. The biggest danger is that through the bacteria pollution of environment can lead to breakouts of different epidemic diseases.

The dangerous wastes are also the wastes of agricultural production – manures, residues of chemicals, chemical fertilizer and pesticides, as well animal cemeteries, which died during the epidemics. Although these wastes have a dotted character, their big quantity and high concentration of toxic substances in them can effect environment very negative.

One of the reasons of forest destruction in many world regions is acid rains, which are caused by activity of power stations. Blowouts of sulfur dioxide and its spread for the long distances lead to acid rains far from the source these blowouts.

For the last 20 years the world lost almost 200 million hectares of forest. The most dangerous is exhaustion of tropical forests, because they are the lungs of the planet and the main source of biological variety on the planet.

Annually 200 thousand quadrat kilometers of forest are cut down and burned, and it means that 100 thousand species of plants and animals disappear. The most quickly this process is going in the richest regions of tropic forests – Amazonia and Indonesia.

The British ecologist N. Meyers came to conclusion, that 10 small regions in tropics have at least 27% of all species composition, later this list was broaden to 15 small tropic regions, which must be saved at any price.

Speaking about different ways of ecological situation evolution in the world, the most important is the topic about nowadays ways of environment protection. Despite that all above discussed problems have their solution variants; there is main approach of solving these environment problems. Except this for the last century the mankind worked out some original methods of fighting with its own disadvantages, which ruin the nature and environment. To such methods or better to say ways we can rank the occurrence and activity of different “green” motions and organizations. Except the famous “Green peace”, which have a really wide activity, and sometimes it’s extremist enough, and other similar organizations, which organize nature protective actions, there is another type of ecological organizations – the structure that stimulate and sponsor the nature protective activity, “Wide Fund for Nature” as example. The all ecological organizations can be public, private, state or mixed type.

Except different kinds of organizations, which protect the nature, there are also many state and public nature protective initiatives. For example “International Red Book” is a list of rare and threatened species of animals and plants. At the moment it includes 5 tomes. Also there are national and regional “Red Books”.

As a way to solve ecological problems many researchers call introduction of ecological clean, few wastes and wasteless technologies, building of cleaning constructions, rational industry placement and rational using of natural resources.

But first of all the most important way to solve all these problems is increase of peoples ecological culture, deep ecological education. This can help to fight the consumer attitude to the nature.

Some people say that we should invest money in ecology projects, while others believe that nature is doing well by itself.

The earth is the only planet that people can live on, but nowadays they seem to be doing everything to make their home unfit for living. Industrialization has brought us into conflict with the natural environment. Our planet is in danger; air, water and land pollution have disastrous consequences which threaten human life on Earth.

I strongly feel that the more money is invested in ecology projects, the better our lives are going to be. People have technologies to make our planet cleaner: we can control pollution, recycle waste materials, protect rare animals and plants and install antipollution equipment. We need more disaster-prevention programs in order to control environmental pollution, fight the destruction of wildlife and preserve woodlands. There should be more organizations like Greenpeace that will help protect the animal world and stop environmental degradation. Such organizations influence public opinion and help form a correct attitude to nature. There should be more newspaper articles, TV-programs and science-popular films about ecological problems. They help people become environment-educated.

However, many people still believe that nature is doing well by itself. They use natural resources and pollute the environment, but they don't think how awful the consequences may be. I'm sure that nature can't do without our help. If we want to breathe fresh air, to drink clean water and to eat healthy food, we must stop polluting the environment.

To conclude, ecological problems concern everybody and there are ways to solve them. People must always remember that the earth is our home and it depends on us what it will be like.

Many people think that they can't solve the world's environmental problems on their own and that the government and big companies must care about these problems. However, others say that individuals can do much to help the environment.

Our planet is in danger: air, water and land pollution have disastrous consequences which threaten human life on Earth. Most people are convinced that something must be done to stop pollution, but they don't know if they can help.

In my opinion, much can be done by an average citizen. People have to be smart about such things as driving a car or using electricity. Whenever we drive a car, we are adding greenhouse gases to the atmosphere. To make our planet cleaner and to use less energy we can try carpooling. That is when three people ride together in one car instead of driving three cars to work. We can also use public transport, ride a bike, or walk. People can save electricity by turning off lights, our TV-set and computer. We can use less washing up liquids to keep the water clean. We can also plant trees, collect litter and recycle cans, bottles, plastic bags and newspapers. Besides, we can buy products that don't use much energy.