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ECOLOGY
YU.
F. FLORINSKAYA
Human impact on the environment
The more we take from the world, the less we leave in it, and eventually we will be forced to pay our debts at the very moment that may be very unsuitable for ensuring the continuation of our life.
Norbert Wiener
Man began to change natural complexes already at the primitive stage of the development of civilization, during the period of hunting and gathering, when he began to use fire.
The domestication of wild animals and the development of agriculture have expanded the territory of manifestation of the consequences of human activity.
With the development of industry and the replacement of muscle power with fuel energy, the intensity of anthropogenic influence continued to increase.
In the XX century, due to the particularly rapid growth of the population and its needs, it reached an unprecedented level and spread to the whole world.
When considering the human impact on the environment, we must always remember the most important ecological postulates formulated in Tyler Miller's wonderful book "Life in the Environment".
1. Whatever we do in nature, everything causes certain consequences in it, often unpredictable.
2. Everything in nature is interconnected, and we all live in it together.
3. Earth's life support systems can withstand significant pressure and rough interventions, but there is a limit to everything.
4. Nature is not only more complex than we think about it, it is much more complex than we can imagine.
All man made complexes (landscapes) can be divided into two groups, depending on the purpose of their occurrence:
- direct – created by purposeful human activity: cultivated fields, garden and park complexes, reservoirs, etc., they are often called cultural;
- concomitant – not foreseen and usually undesirable, which were activated or brought to life by human activity: swamps on the banks of reservoirs, ravines in the fields, quarry dump landscapes, etc.
Each anthropogenic landscape has its own history of development, sometimes very complex and, most importantly, extremely dynamic.
In a few years or decades, anthropogenic landscapes can undergo such profound changes that natural landscapes will not experience in many thousands of years.
The reason for this is the continuous human intervention in the structure of these landscapes, and this intervention necessarily affects the person himself.
Here is just one example.
In 1955, when nine out of every ten residents of North Borneo fell ill with malaria, on the recommendation of the World Health Organization (WHO), the toxic chemical dieldrin was sprayed on the island to control malaria – carrying mosquitoes.
The disease was practically banished, but the unforeseen consequences of such a struggle turned out to be terrible: not only mosquitoes died from dieldrin, but also other insects, in particular flies and cockroaches; then lizards who lived in houses and ate dead insects died; after that, cats who ate dead lizards began to die; without cats, rats began to multiply rapidly – and people were threatened with a plague epidemic.
We got out of this situation by parachuting healthy cats.
But... it turned out that dieldrin did not affect the caterpillars, but destroyed those insects that fed on them, and then numerous caterpillars began to eat not only the leaves of trees, but also the leaves that served as a roof for roofs, as a result, roofs began to collapse.
Anthropogenic changes in the environment are very diverse.
By directly affecting only one of the components of the environment, a person can indirectly change the rest.
Both in the first and in the second case, there is a violation of the circulation of substances in the natural complex, and from this point of view, the results of the impact on the environment can be attributed to several groups.
The first group includes effects that lead only to a change in the concentration of chemical elements and their compounds without changing the shape of the substance itself.
For example, as a result of emissions from road transport, the concentration of lead and zinc increases in the air, soil, water and plants, many times exceeding their usual content.
In this case, the quantitative assessment of the impact is expressed in the mass of pollutants.
The second group – impacts lead not only to quantitative, but also to qualitative changes in the forms of finding elements (within individual anthropogenic landscapes).
Such transformations are often observed during the development of deposits, when many elements of ores, including toxic heavy metals, pass from the mineral form into aqueous solutions.
At the same time, their total content within the complex does not change, but they become more accessible to plant and animal organisms.
Another example is the changes associated with the transition of elements from a biogenic form to an abiogenic one.
So, a person when cutting down forests, cutting down a hectare of pine forest, and then burning it, converts about 100 kg of potassium, 300 kg of nitrogen and calcium, 30 kg of aluminum, magnesium, sodium, etc. from a biogenic form to a mineral one.
The third group is the formation of technogenic compounds and elements that have no analogues in nature or are not characteristic of this area.
There are more and more such changes every year.
These are the appearance of freon in the atmosphere, plastics in soils and waters, weapons grade plutonium, caesium in the seas, the widespread accumulation of poorly decomposing pesticides, etc.
In total, about 70,000 different synthetic chemicals are used daily in the world.
About 1,500 new ones are added to them every year.
It should be noted that little is known about the environmental impact of most of them, but at least half of them are harmful or potentially harmful to human health.
The fourth group is the mechanical movement of significant masses of elements without a significant transformation of the forms of their location.
An example is the movement of rock masses during the development of deposits both open and underground.
Traces of quarries, underground voids and terricons (hills with steep slopes formed by spent waste rocks moved from mines) will exist on Earth for many thousands of years.
The same group includes the movement of significant soil masses during dust storms of anthropogenic origin (one dust storm is able to transfer about 25 km3 of soil).
Analyzing the results of human activity, it is necessary to take into account the state of the natural complex itself, its resistance to impacts.
The concept of sustainability is one of the most complex and controversial concepts in geography.
Any natural complex is characterized by certain parameters, properties (one of them, for example, is the amount of biomass).
Each parameter has a threshold value – the amount at which changes in the qualitative state of the components occur.
These thresholds are practically not studied, and often, predicting future changes in natural complexes under the influence of a particular activity, it is impossible to specify the specific scale and exact time frame of these changes.
What are the real scales of modern anthropogenic influence?
Here are some numbers.
Annually, over 100 billion tons of minerals are extracted from the bowels of the Earth; 800 million tons of various metals are smelted; more than 60 million tons of synthetic materials are produced that are not known in nature; more than 500 million tons of mineral fertilizers and about 3 million tons of various pesticides are introduced into the soils of agricultural lands, 1/3 of which comes from surface runoff into reservoirs or is delayed in the atmosphere (when dispersed from aircraft).
For their needs, people use more than 13% of river runoff and discharge more than 500 billion m3 of industrial and municipal wastewater into reservoirs annually.
The enumeration can be continued, but the above is enough to realize the global nature of human influence on the environment, and therefore the global nature of the problems arising in this regard.
Let's consider the consequences of the three main types of human economic activity, although, of course, they do not exhaust the entire complex of anthropogenic influence on the habitat.
Industry – the largest branch of material production plays a central role in the economy of modern society and is the main driving force of its growth.
Over the past century, world industrial production has increased more than 50 (!) times, and 4/5 of this growth has occurred since 1950, i.e. the period of active introduction of scientific and technological progress into production Naturally, such a rapid growth of industry, which ensures our well being, primarily affected the environment, the load on which has increased many times.
Industry and its products affect the environment at all stages of the industrial cycle: from the exploration and production of raw materials, its processing into finished products, waste generation and ending with the use of finished products by the consumer, and then its liquidation due to further unsuitability.
At the same time, land is alienated for the construction of industrial facilities and entrances to them; constant use of water (in all industries)1; release of substances from the processing of raw materials into water and air; removal of substances from the soil, rocks, biosphere, etc.
The load on landscapes and their components in the leading industries is carried out as follows.
Energy is the basis for the development of all branches of industry, agriculture, transport, and public utilities.
This is an industry with very high rates of development and huge production scales.
Accordingly, the share of participation of energy enterprises in the load on the natural environment is very significant.
The annual energy consumption in the world is more than 10 billion tons of conventional fuel, and this figure is continuously increasing .2 For energy production, either fuel is used – oil, gas, coal, wood, peat, shale, nuclear materials, or other primary energy sources – water, wind, solar energy, etc.
Almost all fuel resources are non renewable – and this is the first stage of the impact on the nature of the energy industry – the irrevocable removal of masses of matter.
Each of the sources, when used, is characterized by specific parameters of pollution of natural complexes.
Coal is the most common fossil fuel on our planet.
When burning it, carbon dioxide, fly ash, sulfur dioxide, nitrogen oxides, fluoride compounds, as well as gaseous products of incomplete combustion of fuel enter the atmosphere.
Sometimes fly ash contains extremely harmful impurities, such as arsenic, free silicon dioxide, free calcium oxide.
Oil.
When burning liquid fuel, in addition to carbon dioxide, sulfur dioxide and sulfur anhydrides, nitrogen oxides, vanadium, sodium compounds, gaseous and solid products of incomplete combustion enter the air.
Liquid fuel produces less harmful substances than solid fuel, but the use of oil in the energy sector is decreasing (due to the exhaustion of natural reserves and its exclusive use in transport, in the chemical industry).
Natural gas is the most harmless of the fossil fuels.
When it is burned, the only significant atmospheric pollutant other than CO2 is nitrogen oxides.
Wood is most used in developing countries (70% of the population of these countries burns an average of about 700 kg per person per year).
Wood burning is harmless – carbon dioxide and water vapor enter the air, but the structure of biocenoses is disturbed – the destruction of forest cover causes changes in all components of the landscape.
The use of nuclear fuel is one of the most controversial issues in the modern world.
Of course, nuclear power plants pollute the atmospheric air to a much lesser extent than thermal power plants (using coal, oil, gas), but the amount of water used at nuclear power plants is twice as much as consumption at thermal power plants – 2.5–3 km3 per year at nuclear power plants with a capacity of 1 million kW, and thermal discharge at nuclear power plants per unit of energy produced is significantly more than at thermal power plants under similar conditions.
But the problems of radioactive waste and the safety of operation of nuclear power plants cause especially heated disputes.
The enormous consequences for the natural environment and humans of possible accidents at nuclear reactors do not allow us to treat nuclear energy as optimistically as it was in the initial period of using the "peaceful atom".
If we consider the impact of the utilization of fossil fuels on other components of natural complexes, then we should highlight the impact on natural waters.
For the needs of cooling generators, a huge water intake is produced at power plants: 200 to 400 liters of water are needed to generate 1 kW of electricity; a modern thermal power plant with a capacity of 1 million kW requires 1.2–1.6 km3 of water during the year.
As a rule, water intake for cooling systems of power plants is 50-60% of the total industrial water withdrawal.
The return of waste water heated in cooling systems causes thermal pollution of water, as a result of which, in particular, the solubility of oxygen in water decreases and at the same time the vital activity of aquatic organisms is activated, which begin to consume more oxygen.
The next aspect of the negative impact on the landscape during the extraction of fuels is the alienation of large areas where vegetation is destroyed, the soil structure and water regime change.
This applies primarily to open methods of fuel extraction (in the world, about 85% of minerals and building materials are extracted by open method).
Among other primary sources of energy – wind, river water, the sun, tides, underground heat – a special place is occupied by water.
Geothermal power plants, solar panels, wind turbines, tidal power plants have the advantage of a minor impact on the environment, but their distribution in the modern world is still quite limited.
River waters used by hydroelectric power plants (HPPs) that convert the energy of the water flow into electrical energy have practically no polluting effect on the environment (with the exception of thermal pollution).
Their negative impact on the environment is different.
Hydraulic structures, primarily dams, violate the regimes of rivers and reservoirs, prevent the migration of fish, affect the groundwater level.
Reservoirs created to equalize river flow and uninterrupted supply of hydroelectric power plants with water also have a detrimental effect on the environment.
The total area of only large reservoirs in the world is 180 thousand km2 (the same amount of land is flooded), and the volume of water in them is about 5 thousand km3.
In addition to land flooding, the creation of reservoirs greatly changes the flow regime of rivers, affects local climatic conditions, which, in turn, affects the vegetation cover along the banks of the reservoir.
Metallurgy.
The impact of metallurgy begins with the extraction of ferrous and non – ferrous metal ores, a number of which, such as copper and lead, have been used since ancient times, while others – titanium, beryllium, zirconium, germanium have been actively used only in recent decades (for the needs of radio engineering, electronics, nuclear technology).
But since the middle of the XX century, due to the scientific and technical revolution, the extraction of both new and traditional metals has sharply increased, and therefore the number of natural disturbances associated with the movement of significant masses of rocks has increased.
In addition to the main raw materials – metal ores – metallurgy actively consumes water.
Approximate figures of water consumption for the needs of, for example, ferrous metallurgy are as follows: about 100 m3 of water is spent on the production of 1 ton of cast iron; 300 m3 is spent on the production of 1 ton of steel; 30 m3 of water is spent on the production of 1 ton of rolled products.
But the most dangerous side of the impact of metallurgy on the environment is the technogenic dispersion of metals.
With all the difference in the properties of metals, all of them are impurities in relation to the landscape.
Their concentration can increase tens and hundreds of times without external changes in the environment (water remains water, and soil remains soil, but the mercury content in them increases tenfold).
The main danger of dispersed metals is their ability to gradually accumulate in the organisms of plants and animals, which disrupts the food chain.
Metals enter the environment at almost all stages of metallurgical production.
Part of it is lost during transportation, processing, sorting of ores.
So, in one decade at this stage, about 600 thousand tons of copper, 500 thousand tons of zinc, 300 thousand tons of lead, 50 thousand tons of molybdenum were scattered around the world.
Further emission occurs directly at the production stage (and not only metals, but also other harmful substances are emitted).
The air around the metallurgical enterprises is smoky, there is an increased dust content in it.
Nickel production is characterized by emissions of arsenic and large amounts of sulfur dioxide (SO2); aluminum production is accompanied by emissions of fluorine, etc.
Environmental pollution is also carried out by waste water from metallurgical plants.
The most dangerous pollutants include lead, cadmium and mercury, followed by copper, tin, vanadium, chromium, molybdenum, manganese, cobalt, nickel, antimony, arsenic and selenium.
In the changing landscape around metallurgical enterprises, two zones can be distinguished.
The first, with a radius of 3-5 km, directly adjacent to the enterprise, is characterized by almost complete destruction of the original natural complex.
There is often no vegetation here, the soil cover is largely disturbed, the animals and microorganisms that inhabited the complex have disappeared.
The second zone is more extensive, up to 20 km, looks less oppressed – there is rarely a disappearance of the biocenosis, but its individual parts are disturbed and an increased content of pollutants is observed in all components of the complex.
The chemical industry is one of the most dynamic industries in most countries; new production facilities are often created in it, new technologies are introduced.
But it is also associated with the emergence of many modern problems of environmental pollution caused by both its products and technological processes of production.
This industry, like metallurgy and energy, is among the extremely water intensive.
Water is involved in the production of most of the most important chemical products – alkalis, alcohols, nitric acid, hydrogen, etc.
The production of 1 ton of synthetic rubber requires up to 2800 m3 of water, 1 ton of rubber 4000 m3, 1 ton of synthetic fiber 5000 m3.
After use, the water partially returns to the reservoirs in the form of highly polluted wastewater, which leads to a weakening or suppression of the vital activity of aquatic organisms, which makes it difficult for the processes of self purification of reservoirs.
The composition of air emissions from chemical enterprises is also extremely diverse.
Petrochemical industries pollute the atmosphere with hydrogen sulfide and hydrocarbons; the production of synthetic rubber – with styrene, divinyl, toluene, acetone; the production of alkalis – with hydrogen chloride, etc.
Substances such as carbon and nitrogen oxides, ammonia, inorganic dust, fluorinated substances and many others are also emitted in large quantities.
One of the most problematic aspects of the impact of chemical production is the spread of previously non existent compounds in nature.
Among them, synthetic surfactants – SPAV (sometimes they are called detergents) are considered particularly harmful.
They get into the environment during the production and use of various detergents in everyday life.
Entering industrial and domestic wastewater into reservoirs, SPAV is poorly delayed by treatment facilities, contributes to the appearance of abundant foam in the water, gives it toxic properties and smell, causes the death and degeneration of aquatic organisms and, very significantly, increases the toxic effect of other pollutants.
These are the main negative impacts on the natural systems of the world's leading industries.
Naturally, the influence of industry is not limited to the above: there is mechanical engineering, which uses the products of metallurgy and chemical industry and contributes to the dispersion of many substances in the environment; there are such water intensive industries as pulp and paper and food, which also provide a large share of organic pollutants, etc.
Based on the analysis of the environmental impact of the three main industries, it is possible to determine the nature and ways of industrial pollution for any industry, for which it is necessary to know the specifics of production.
To be continued
Photo by M. Kabanov
1 The total industrial water withdrawal is about 800 km3 per year, with the value of irretrievable losses of 30-40 km3.
2 The main consumers of energy are developed countries.
For example, in 1989, 249 million Americans used more energy for air conditioning alone than 1.1 billion Chinese for all needs.
