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Pollution of the world's oceans: the importance of the problem, the main factors and ways to overcome it. Pollution of the world's oceans

Pollution of the world's oceans: the importance of the problem, the main factors and ways to overcome it. Pollution of the world's oceans

17.10.2019

Land and ocean are connected by rivers that flow into the seas and carry various pollutants. Chemicals that do not break down on contact with the soil, such as petroleum products, oil, fertilizers (especially nitrates and phosphates), insecticides and herbicides, are leached into rivers and then into the ocean.

Oil and oil products are the main pollutants of the oceans, but the damage they cause is greatly exacerbated by sewage, household garbage and air pollution.

A study of the North Sea showed that about 65% of the pollutants found there were carried by rivers. Another 25% of the pollutants came from the atmosphere (including 7,000 tons of lead from car exhausts), 10% from direct discharges (mostly sewage), and the rest from discharges and discharges of waste from ships.

Ecological disasters

All serious cases of ocean pollution are associated with oil. As a result of the widespread practice of washing the holds of tankers, between 8 and 20 million barrels of oil are deliberately dumped into the ocean every year.

In 1989, the Exxon Valdez tanker ran aground in the Alaska region, and an oil slick as a result of a spill of almost 11 million gallons (about 50 thousand tons) of oil stretched for 1600 km along the coast. The Exxon Valdez is one of the most famous offshore oil spills.

Wastewater

In addition to oil, sewage is one of the most hazardous wastes. In small quantities, they enrich the water and promote the growth of plants and fish, and in large quantities they destroy ecosystems. There are two largest waste disposal sites in the world - Los Angeles (USA) and Marseille (France). Wastewater kills marine life, creating underwater deserts littered with organic debris.

Metals and chemicals

In recent years, the content of metals, DDT and PCBs (polychlorinated biphenyls) in the waters of the oceans has decreased, while the amount of arsenic has inexplicably increased. DDT (a long-lived, naturally occurring toxic organochlorine pesticide) has been banned in most developed countries, but is still used in parts of Africa. These industrial pollutants are poison to animals and humans. Like other ocean pollutants, such as those used in pesticides and wood preservatives, HCH (hexachlorocyclohexane), they are persistent chlorine compounds.

These chemicals leach out of the soil and end up in the sea, where they penetrate the tissues of living organisms. PCBs accumulate in marine organisms and have a cumulative effect. Fish with PCBs or HCH can be eaten by both humans and fish. The fish are then eaten by seals, which in turn become food for certain species of whales or polar bears. Each time chemicals move from one level of the food chain to another, their concentration rises. An unsuspecting polar bear eating a dozen seals also ingests the toxins contained in tens of thousands of infected fish.

Hazardous chemicals that can disrupt the ecological balance include heavy metals such as cadmium, nickel, arsenic, copper, lead, zinc and chromium. According to estimates, up to 50,000 tons of these metals are annually discharged into the North Sea alone. Of even greater concern are pesticides - aldrin, dieldrin and endrin - accumulating in animal tissues. The long-term effects of the use of such chemicals are not yet known.

Detrimental to marine life and TBT (tributyl tin chloride), widely used for painting the keels of ships and preventing them from fouling with shells and algae. TBT has been proven to change the sex of male trumpeters (a type of crustacean); as a result, the entire population consists of females, which excludes the possibility of reproduction.

Impact on ecosystems

All oceans suffer from pollution, but pollution in coastal waters is higher than in the open ocean due to a much larger number of sources of pollution, from coastal industrial installations to heavy ship traffic. Around Europe and off the eastern coast of North America, cages are being set up on shallow continental shelves to breed oysters, mussels and fish vulnerable to toxic bacteria, algae and pollutants. In addition, offshore oil exploration is underway, which increases the risk of oil spills and pollution.

The waters of the Mediterranean Sea are completely renewed every 70 years by the Atlantic Ocean, with which it communicates. Up to 90% of wastewater comes from 120 coastal cities, and other pollutants come from 360 million people living or holidaying in 20 Mediterranean countries. This sea has turned into a huge polluted ecosystem, which annually receives about 430 billion tons of waste. The sea coasts of Spain, France and Italy are the most polluted, which is explained by the influx of tourists and the work of heavy industry enterprises.

water bloom

Another common type of ocean pollution is water blooms due to the massive development of algae or plankton. In the waters of the temperate zone, such phenomena have been known for quite a long time, but in the subtropics and tropics, the "red tide" was first noticed near Hong Kong in 1971. Subsequently, such cases were often repeated. It is believed that this is due to industrial emissions of a large number of trace elements that act as biostimulators of plankton growth.

All marine animals that obtain food by filtering water are very sensitive to pollutants that accumulate in their tissues. Corals, made up of giant colonies of single-celled organisms, do not tolerate pollution well. These living communities - coral reefs and atolls - are under serious threat.

Pollution with plastic waste

Accumulations of plastic waste form in the oceans, under the influence of currents, special garbage patches. At the moment, five large accumulations of garbage patches are known - two each in the Pacific and Atlantic oceans and one in the Indian Ocean. These garbage cycles mainly consist of plastic waste generated as a result of discharges from the densely populated coastal zones of the continents. Plastic waste is also dangerous because marine animals often cannot see the transparent particles floating on the surface, and toxic waste enters their stomach, often causing death.

man and ocean

Number of whales killed by different countries annually:

Canada: 1 bowhead whale every two years in Hudson Bay and one bowhead whale every 13 years in Bafina Bay.
Faroe islands: 950 pilot whales annually.
Greenland:
175 whales per year.
Iceland: 30 minke whales and 9 finned whales.
Indonesia: 10 to 20 whales.
Japan: the quota for the whaling fleet in 2009 and 2010 was 935 minke whales, 50 finned whales and 50 humpback whales, although the fleet returned with a smaller catch, because. was stopped by public organizations preventing the slaughter of whales. About 20,000 dolphins and small whales are killed by coastal fishermen. In 2009, about 150 large whales died in the nets of coastal fishermen.
Norway: the quota for the whaling fleet in 2011 was 1,286 minke whales.

That's about 7,400 whales a year, not counting dolphins, or 20 whales every day!

To date, the population of sharks in the oceans has fallen by 95-98%, every year a person kills 100 million sharks, or 11,000 sharks every hour. Sharks are only killed for their fins, which are highly valued in the Chinese traditional market, and teeth are also used as souvenirs for tourists. Shark meat has no nutritional value.

Very often, sharks simply cut off their fins and are left alive to die at the bottom of the sea. Until now, there is an industrial catch of sharks, paradoxically, several shark processing plants are located in the United States.

The whale shark is the largest fish on the planet, the largest specimen caught in India in 1983 reached 12m. The whale shark, being a harmless giant, feeds on plankton and is absolutely not dangerous to humans, on the other hand, humans ruthlessly exterminate this giant of the seas. Scientists estimate that between 1993 and 2001, the whale shark population fell by 83%. In 2002, the whale shark was listed as critically endangered. The whale shark is still hunted in the Philippines and Mozambique.
The whale shark reaches sexual maturity after 20 years of life.
A whale shark's dorsal fin can cost up to US$10,000.

Manta is one of the most mysterious creatures on the planet. To this day, scientists know very little about this large fish, reaching 7m. in wingspan and feeding on plankton. The manta has an unusually large brain compared to the size of the body, having a special system - a network of blood vessels surrounding the brain, due to which the temperature of the brain is kept higher than the rest of the body. Not much is known about the habitats and migrations of manta rays. Manta rays do not live in captivity, the only aquarium where this has been done is in Okinawa, Japan. Manta rays, like their shark counterparts, are mercilessly exterminated, the reason is the same - their cartilage is used in Chinese traditional cuisine. For example, a dead manta ray in the Philippines costs 400 US$.

The story of the senseless extermination of a magnificent bird, the now extinct great auk, is an example of human greed and complete indifference to the fate of the world around us. The flightless auk, a flightless bird with a dense body, about 75 cm tall, was similar to modern penguins. The auk was very clumsy on land, but surprisingly graceful and dexterous underwater, swimming about 5000 km annually. from wintering grounds off the coast of North Carolina to nesting grounds on rocky islands around Iceland, Greenland and Newfoundland. The extermination of unfortunate birds was carried out intensively and thoughtlessly. The fishermen, having driven the birds to the island, began to beat them with heavy sticks, and then loaded the carcasses into the boats. They were fired from guns loaded with pieces of metal, old nails, chain links and lead bullets. It happened that the auks were simply forced to climb a board laid from the shore to the side of the boat, then the sailors were waiting for them - they broke the skulls of the birds with heavy sticks.

Every year, a huge number of porpoises die in fishing nets, another serious danger to these mammals is Japanese whalers who knock out these defenseless animals. For example, in 1988 alone, 40,000 porpoises were killed.

The rate at which pollutants enter the oceans has increased dramatically in recent years. Every year, up to 300 billion m 3 of wastewater is discharged into the ocean, 90% of which is not previously treated. Marine ecosystems are exposed to increasing anthropogenic impact through chemical toxicants, which, accumulating by hydrobionts along the trophic chain, lead to the death of consumers of even high orders, including terrestrial animals - seabirds, for example. Among chemical toxicants, petroleum hydrocarbons (especially benz(a)pyrene), pesticides, and heavy metals (mercury, lead, cadmium, etc.) pose the greatest danger to marine biota and humans. In the Sea of Japan, “red tides” became a real disaster, a consequence of eutrophication, in which microscopic algae flourish, and then oxygen in the water disappears, aquatic animals die and a huge mass of rotting residues is formed that poisons not only the sea, but also the atmosphere.

According to Yu.A. Israel (1985), the environmental consequences of pollution of marine ecosystems are expressed in the following processes and phenomena (Fig. 7.3):

violation of the stability of ecosystems;
progressive eutrophication;
the appearance of "red tides";
accumulation of chemical toxicants in biota;
decrease in biological productivity;
the occurrence of mutagenesis and carcinogenesis in the marine environment;
microbiological pollution of coastal areas of the sea.

Rice. 7.3.

To a certain extent, marine ecosystems can withstand the harmful effects of chemical toxicants using the accumulative, oxidizing and mineralizing functions of aquatic organisms. For example, bivalve mollusks are able to accumulate one of the most toxic pesticides - DDT and, under favorable conditions, remove it from the body. (DDT is known to be banned in Russia, the United States, and some other countries; nevertheless, it enters the World Ocean in significant quantities.) Scientists have also proved the existence in the waters of the World Ocean of intensive processes of biotransformation of a hazardous pollutant, benzo (a) pyrene, thanks to the presence of heterotrophic microflora in open and semi-enclosed water areas. It has also been established that the microorganisms of reservoirs and bottom sediments have a sufficiently developed mechanism of resistance to heavy metals, in particular, they are able to produce hydrogen sulfide, extracellular exopolymers and other substances that, interacting with heavy metals, convert them into less toxic forms.

At the same time, more and more toxic pollutants continue to enter the ocean. The problems of eutrophication and microbiological pollution of coastal zones of the ocean are becoming more and more acute. In this regard, it is important to determine the allowable anthropogenic pressure on marine ecosystems, to study their assimilation capacity as an integral characteristic of the ability of biogeocenosis to dynamically accumulate and remove pollutants.

Oil pollution of the oceans is undoubtedly the most widespread phenomenon. From 2 to 4% of the water surface of the Pacific and Atlantic oceans is constantly covered with an oil slick. Up to 6 million tons of oil hydrocarbons enter sea waters annually. Almost half of this amount is associated with the transportation and development of deposits on the shelf. Continental oil pollution enters the ocean through river runoff. The rivers of the world annually carry out into the sea and ocean waters more than 1.8 million tons of oil products.

At sea, oil pollution takes many forms. It can cover the surface of the water with a thin film, and in case of spills, the thickness of the oil coating can initially be several centimeters. Over time, an oil-in-water or water-in-oil emulsion is formed. Later, there are lumps of heavy fraction of oil, oil aggregates that are able to float on the surface of the sea for a long time. Various small animals are attached to floating lumps of fuel oil, which fish and baleen whales willingly feed on. Together with them, they swallow oil. Some fish die from this, others are soaked through with oil and become unsuitable for eating due to an unpleasant smell and taste.

All components are non-toxic to marine organisms. Oil affects the structure of the marine animal community. With oil pollution, the ratio of species changes and their diversity decreases. So, microorganisms that feed on petroleum hydrocarbons develop abundantly, and the biomass of these microorganisms is poisonous to many marine life. It has been proven that long-term chronic exposure to even small concentrations of oil is very dangerous. At the same time, the primary biological productivity of the sea is gradually decreasing. Oil has another unpleasant side property. Its hydrocarbons are capable of dissolving a number of other pollutants, such as pesticides, heavy metals, which, together with oil, are concentrated in the surface layer and poison it even more. The aromatic fraction of oil contains substances of a mutagenic and carcinogenic nature, such as benzo(a)pyrene. Much evidence has now been obtained for the mutagenic effects of polluted marine environments. Benz(a)pyrene circulates extensively in marine food chains and ends up in human food.

The largest amounts of oil are concentrated in a thin surface layer of sea water, which is of particular importance for various aspects of ocean life. Many organisms are concentrated in it, this layer plays the role of a "kindergarten" for many populations. Surface oil films disrupt gas exchange between the atmosphere and the ocean. The processes of dissolution and release of oxygen, carbon dioxide, heat transfer undergo changes, the reflectivity (albedo) of sea water changes.

Chlorinated hydrocarbons, widely used as a means of combating pests in agriculture and forestry, with carriers of infectious diseases, have been entering the World Ocean along with river runoff and through the atmosphere for many decades. DDT and its derivatives, polychlorinated biphenyls and other stable compounds of this class are now found throughout the world's oceans, including the Arctic and Antarctic.

They are easily soluble in fats and therefore accumulate in the organs of fish, mammals, seabirds. Being xenobiotics, i.e. substances of completely artificial origin, they do not have their “consumers” among microorganisms and therefore almost do not decompose under natural conditions, but only accumulate in the oceans. At the same time, they are acutely toxic, affect the hematopoietic system, inhibit enzymatic activity, and strongly affect heredity.

Along with river runoff, heavy metals also enter the ocean, many of which have toxic properties. The total value of the river runoff is 46 thousand km 3 of water per year. Together with it, up to 2 million tons of lead, up to 20 thousand tons of cadmium and up to 10 thousand tons of mercury enter the World Ocean. Coastal waters and inland seas have the highest pollution levels. significant role in pollution

The ocean plays and the atmosphere. For example, up to 30% of all mercury and 50% of lead entering the ocean annually is transported through the atmosphere.

Due to its toxic effect in the marine environment, mercury is of particular danger. Under the influence of microbiological processes, toxic inorganic mercury is converted into much more toxic organic forms. Methylmercury compounds accumulated through bioaccumulation in fish or shellfish pose a direct threat to human life and health. Let us recall at least the infamous Minamata disease, which got its name from the Gulf of Japan, where mercury poisoning of local residents was so sharply manifested. It claimed many lives and undermined the health of many people who ate seafood from this bay, at the bottom of which a lot of mercury accumulated from waste from a nearby plant.

Mercury, cadmium, lead, copper, zinc, chromium, arsenic and other heavy metals not only accumulate in marine organisms, thereby poisoning marine food, but also adversely affect marine life. Accumulation coefficients of toxic metals, i.e. their concentration per unit weight in marine organisms in relation to sea water varies widely - from hundreds to hundreds of thousands, depending on the nature of the metals and types of organisms. These coefficients show how harmful substances accumulate in fish, molluscs, crustaceans, plankton and other organisms.

The scale of pollution of products of the seas and oceans is so great that in many countries sanitary standards have been established for the content of certain harmful substances in them. It is interesting to note that at only 10 times the natural concentration of mercury in the water, oyster contamination already exceeds the limits set in some countries. This shows how close the limit of sea pollution is, which cannot be crossed without harmful consequences for human life and health.

However, the consequences of pollution are dangerous, first of all, for all living inhabitants of the seas and oceans. These consequences are varied. Primary critical disturbances in the functioning of living organisms under the influence of pollutants occur at the level of biological effects: after a change in the chemical composition of cells, the processes of respiration, growth and reproduction of organisms are disturbed, mutations and carcinogenesis are possible; movement and orientation in the marine environment are disturbed. Morphological changes often manifest themselves in the form of various pathologies of internal organs: changes in size, development of ugly forms. Especially often these phenomena are recorded in chronic pollution.

All this is reflected in the state of individual populations, in their relationships. Thus, there are environmental consequences of pollution. An important indicator of the violation of the state of ecosystems is a change in the number of higher taxa - fish. The photosynthetic action as a whole changes significantly. The biomass of microorganisms, phytoplankton, zooplankton is growing. These are characteristic signs of eutrophication of marine water bodies, they are especially significant in inland seas, seas of a closed type. In the Caspian, Black, Baltic Seas over the past 10-20 years, the biomass of microorganisms has grown almost 10 times.

Pollution of the World Ocean leads to a gradual decrease in primary biological production. According to scientists, it has decreased by 10% by now. Accordingly, the annual growth of other inhabitants of the sea also decreases.

What will be the near future for the World Ocean, for the most important seas? In general, for the World Ocean, it is expected to increase its pollution by 1.5-3 times over the next 20-25 years. Accordingly, the environmental situation will also worsen. The concentrations of many toxic substances can reach a threshold level, and then the natural ecosystem will be degraded. It is expected that the primary biological production of the ocean may decrease in a number of large areas by 20-30% compared to the current one.

The path that will allow people to avoid the ecological impasse is now clear. These are non-waste and low-waste technologies, the transformation of waste into useful resources. But it will take decades to bring the idea to life.

Control questions

1. What are the ecological functions of water on the planet?
2. What changes did the appearance of life on the planet bring to the water cycle?
3. How does the water cycle occur in the biosphere?
4. What determines the amount of transpiration? What is its scope?
5. What is the ecological significance of vegetation cover from the standpoint of geoecology?
6. What is meant by pollution of the hydrosphere? How does it manifest itself?
7. What are the types of water pollution?
8. What is the chemical pollution of the hydrosphere? What are its types and features?
9. What are the main sources of surface and groundwater pollution?
10. What substances are the main pollutants of the hydrosphere?
11. What are the environmental consequences of hydrosphere pollution for the Earth's ecosystems?
12. What are the consequences for human health of the use of contaminated water?
13. What is meant by the depletion of waters?
14. What are the environmental consequences of pollution of the oceans?
15. How does oil pollution of sea water manifest itself? What are its environmental implications?

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1. Oil pollution of the oceans

World Ocean, a continuous water shell of the Earth, surrounding the land (continents and islands) and having a common salt composition. It occupies about 71% of the earth's surface (in the northern hemisphere - 61%, in the southern - 81%). The average depth is 3795m, the maximum depth is 11022m. (Marian Trench in the Pacific Ocean), the volume of water is approximately 1370 million km3. The world ocean is divided into 4 parts: Pacific, Atlantic, Indian and Arctic oceans. Less than 20% of the total number of species of living organisms found so far on Earth lives in the oceans. The total biomass of the World Ocean is about 30 billion tons. dry organic matter. Even more revealing is this comparison: the oceans account for 98.5% of water and ice on Earth, while inland waters account for only 1.5%. While the average height of the continents is only 840m, the average depth of the World Ocean is 3795m.

Pollution of the waters of the World Ocean has taken catastrophic proportions over the past 10 years. This was largely facilitated by the widespread opinion about the unlimited possibilities of the waters of the World Ocean for self-purification. Many understood this to mean that any waste and garbage in any quantity in the waters of the ocean is subjected to biological processing without harmful consequences for the waters themselves.

Regardless of the type of pollution, whether it is pollution of the soil, atmosphere or water, everything ultimately comes down to pollution of the waters of the World Ocean, where all toxic substances eventually get, turning the World Ocean into a “global garbage dump”.

There are the following sources of their discharge:

- in tankers, washing tanks and draining ballast water;

- in dry cargo ships, bilge water discharge, leakage from tanks or pump rooms;

- spillage during loading and unloading;

- accidental outflow during collision of ships;

- in underwater production, the appearance is not from the surface, but from the bottom.

Oil is a viscous oily liquid that is dark brown in color and has low fluorescence. Oil consists mainly of saturated aliphatic and hydroaromatic hydrocarbons. The main components of oil - hydrocarbons (up to 98%) - are divided into 4 classes:

1. Paraffins (alkenes) - (up to 90% of the total composition) - stable substances, the molecules of which are expressed by a straight and branched chain of carbon atoms. Light paraffins have maximum volatility and solubility in water.

2. Cycloparaffins - (30 - 60% of the total composition) saturated cyclic compounds with 5-6 carbon atoms in the ring. In addition to cyclopentane and cyclohexane, bicyclic and polycyclic compounds of this group are found in oil. These compounds are very stable and difficult to biodegrade.

3. Aromatic hydrocarbons - (20 - 40% of the total composition) - unsaturated cyclic compounds of the benzene series, containing 6 carbon atoms in the ring less than cycloparaffins. Oil contains volatile compounds with a molecule in the form of a single ring (benzene, toluene, xylene), then bicyclic (naphthalene), semicyclic (pyrene).

4. Olefins (alkenes) - (up to 10% of the total composition) - unsaturated non-cyclic compounds with one or two hydrogen atoms at each carbon atom in a molecule that has a straight or branched chain.

Oil and oil products are the most common pollutants in the oceans. Getting into the marine environment, oil first spreads in the form of a film, forming layers of various thicknesses. By the color of the film, you can determine its thickness:

The oil film changes the composition of the spectrum and the intensity of light penetration into the water. The light transmission of thin films of crude oil is 11-10% (280nm), 60-70% (400nm). A film with a thickness of 30-40 microns completely absorbs infrared radiation. When mixed with water, oil forms an emulsion of two types: direct oil in water and reverse water in oil. Direct emulsions, composed of oil droplets with a diameter of up to 0.5 microns, are less stable and are typical for oils containing surfactants. When volatile fractions are removed, oil forms viscous inverse emulsions, which can remain on the surface, be carried by the current, wash ashore and settle to the bottom.

Oil slicks cover: vast areas of the Atlantic and Pacific oceans; the South China and Yellow Seas, the Panama Canal zone, a vast zone along the coast of North America (up to 500-600 km wide), the water area between the Hawaiian Islands and San Francisco in the North Pacific Ocean and many other areas are completely covered. Such oil films are especially harmful in semi-enclosed, inland and northern seas, where they are brought by current systems. Thus, the Gulf Stream and the North Atlantic Current carry hydrocarbons from the shores of North America and Europe to the areas of the Norwegian and Barents Seas. Especially dangerous is the ingress of oil into the seas of the Arctic Ocean and Antarctica, since low air temperatures slow down the processes of chemical and biological oxidation of oil even in summer. Thus, oil pollution is global.

It is estimated that even 15 million tons of oil is enough to cover the Atlantic and Arctic oceans with an oil film. But the content of 10 g of oil in 1 m3 of water is detrimental to fish eggs. An oil film (1 ton of oil can pollute 12 km2 of the sea area) reduces the penetration of sunlight, which has a detrimental effect on the processes of photosynthesis of phytoplankton, the main food base for most living organisms of the seas and oceans. One liter of oil is enough to deprive 400,000 liters of sea water of oxygen. pollution world ocean oil

Oil films can: significantly disrupt the exchange of energy, heat, moisture, gases between the ocean and the atmosphere. But the ocean plays a big role in shaping the climate, produces 60-70 oxygen, which is necessary for the existence of life on Earth.

When oil evaporates from the surface of the water, the presence of its vapor in the air adversely affects human health. Particularly distinguished are the water areas: the Mediterranean, Northern, Irish, Java Seas; Mexican, Biscay, Tokyo bays.

So, almost the entire area of the coast of Italy, washed by the waters of the Adriatic, Ionian, Pyrrhenian, Ligurian seas, with a total length of about 7,500 km, is polluted with waste from oil refineries and waste from 10 thousand industrial enterprises.

The North Sea is no less polluted with waste. But this is a shelf sea - its average depth is 80 m, and in the Dogger Bank area - until recently a rich fishing area - 20 m. At the same time, the rivers flowing into it, especially the largest ones, such as: Rhine, Elbe, Weser, The Thames does not supply the North Sea with clean fresh water, but, on the contrary, they carry thousands of tons of toxic substances into the North Sea every hour.

The danger of the "oil plague" is nowhere so great as in the area between the Elbe and the Thames. This section, where about half a billion tons of crude oil and oil products are transported annually, accounts for 50% of all collisions of ships with a displacement of more than 500 register tons. The sea is also threatened by thousands of kilometers of pipelines carrying oil. There are also accidents on drilling platforms.

If oil covers the gently sloping marshy shores of the southeastern North Sea, the consequences will be much worse. This segment of the coast from the Danish Esbjerg to the Dutch Helder is a unique region of the World Ocean. On the mudflats and in the narrow channels between them, many small marine animals live. Millions of seabirds nest and find their food here, various species of fish spawn, and their juveniles are fattened here before going out to the open sea. Oil will destroy everything.

The public rightly pays great attention to tanker disasters, but we must not forget that nature itself pollutes the seas with oil. According to a common theory, oil, one might say, originated in the sea. So, it is believed that it arose from the remains of myriads of the smallest marine organisms, after the death of settling to the bottom and buried by later geological deposits. Now the child threatens the life of the mother. The use of oil by man, its extraction at sea and transportation by sea - all this is often regarded as a mortal danger to the oceans.

In 1978, there were about 4 thousand tankers in the world, and they transported approximately 1,700 million tons of oil by sea (about 60% of world oil consumption). Now approximately 450 million tons of crude oil (15% of world production per year) comes from deposits located under the seabed. Now more than 2 billion tons of oil is extracted from the sea and transported through it. According to the estimates of the US National Academy of Sciences, 1.6 million tons, or one thousand three hundredth, of this amount enter the sea. But these 1.6 million tons make up only 26% of the oil that, in total, enters the sea in a year. The rest of the oil, about three-quarters of the total pollution, comes from bulk carriers (bilge water, residues of fuels and lubricants accidentally or intentionally dumped into the sea), from natural sources, and most of all from cities, especially from enterprises located on coast or on rivers flowing into the sea.

The fate of oil that has entered the sea cannot be described in detail. Firstly, mineral oils that enter the sea have different composition and different properties; secondly, in the sea they are affected by different factors: wind of various strengths and directions, waves, air and water temperatures. It is also important how much oil got into the water. The complex interactions of these factors have not yet been fully explored.

When a tanker crashes near the shore, seabirds die: oil glues their feathers. Coastal flora and fauna suffer, beaches and rocks are covered with a hard-to-remove layer of viscous oil. If oil is thrown into the open sea, the consequences are completely different. Significant masses of oil may disappear before reaching the shore.

The relatively rapid absorption of oil by the sea is due to several reasons.

The oil evaporates. Gasoline completely evaporates from the surface of the water in six hours. At least 10% of crude oil evaporates per day, and in about 20 days - 50%. But heavier oil products hardly evaporate.

Oil is emulsified and dispersed, that is, broken into small droplets. Strong sea waves promote the formation of oil-in-water and water-in-oil emulsions. In this case, a continuous carpet of oil breaks, turns into small droplets floating in the water column.

Oil dissolves. It contains substances that are soluble in water, although their share is generally small.

The oil that has disappeared from the surface of the sea due to these phenomena is subjected to slow processes leading to its decomposition - biological, chemical and mechanical.

Biodegradation plays an important role. More than a hundred species of bacteria, fungi, algae and sponges are known to be capable of converting petroleum hydrocarbons into carbon dioxide and water. Under favorable conditions, due to the activity of these organisms, from 0.02 to 2 g of oil decomposes per square meter per day at a temperature of 20--30 °. Light fractions of hydrocarbons decompose in a few months, but lumps of bitumen disappear only after a few years.

There is a photochemical reaction. Under the action of sunlight, oil hydrocarbons are oxidized by atmospheric oxygen, forming harmless, water-soluble substances.

Heavy oil residues can sink. So, the same lumps of bitumen can be so densely populated by small sessile marine organisms that after a while they sink to the bottom.

Mechanical decomposition also plays a role. Over time, bitumen lumps become brittle and break into pieces.

Birds are most affected by oil, especially when coastal waters are polluted. The oil glues the plumage, it loses its heat-insulating properties, and, moreover, a bird stained with oil cannot swim. Birds freeze and drown. Even cleaning feathers with solvents does not save all the victims. The rest of the inhabitants of the sea suffer less. Numerous studies have shown that oil that has entered the sea does not pose any permanent or long-term danger to organisms living in the water and does not accumulate in them, so that its entry into humans through the food chain is excluded.

According to the latest data, significant damage to flora and fauna can be inflicted only in special cases. For example, much more dangerous than crude oil are petroleum products made from it - gasoline, diesel fuel, and so on. Dangerous high concentrations of oil in the littoral (tidal zone), especially on the sandy coast.

In these cases, the concentration of oil remains high for a long time, and it does a lot of harm. But fortunately, such cases are relatively rare. Usually, during tanker accidents, oil quickly disperses in water, dilutes, and begins to decompose. It has been shown that oil hydrocarbons can pass through their digestive tract and even through tissues without harm to marine organisms: such experiments were carried out with crabs, bivalves, various types of small fish, and no harmful effects were found for experimental animals.

Oil pollution is a formidable factor affecting the life of the entire oceans. Pollution of high-latitude waters is especially dangerous, where, due to low temperatures, oil products practically do not decompose and are, as it were, “preserved” by ice, so oil pollution can cause serious damage to the environment of the Arctic and Antarctic.

Oil products that have spread over large areas of water basins can change the moisture, gas, and energy exchange between the ocean and the atmosphere. Moreover, in the seas of tropical and middle latitudes, the influence of oil pollution should be expected on a smaller scale than in the polar regions, since thermal and biological factors in low latitudes contribute to a more intensive process of self-purification. These factors are also decisive in the kinetics of the decomposition of chemicals. Regional features of the wind regime also cause a change in the quantitative and qualitative composition of oil films, since the wind contributes to the weathering and evaporation of light fractions of oil products. In addition, the wind acts as a mechanical factor in the destruction of film pollution. On the other hand, the effect of oil pollution on the physical and chemical characteristics of the underlying surface in different geographical areas will also not be unambiguous. For example, in the Arctic, oil pollution changes the reflective radiation properties of snow and ice. A decrease in the albedo value and a deviation from the norm in the processes of melting glaciers and drifting ice is fraught with climatic consequences.

Summing up the above, we can draw conclusions about how the pollution of the World Ocean mainly occurs:

1. During offshore drilling, collection of oil in local reservoirs and pumping through main oil pipelines.

2. As offshore oil production grows, the number of its transportation by tankers increases sharply, and, consequently, the number of accidents also increases. In recent years, the number of large tankers carrying oil has increased. The share of supertankers accounts for more than half of the total volume of oil transported. Such a giant, even after turning on emergency braking, travels more than 1 mile (1852 m) to a complete stop. Naturally, the risk of catastrophic collisions for such tankers increases several times. In the North Sea, where the density of tanker traffic is the highest in the world, about 500 million tons of oil are transported annually, 50 (of all collisions) occur.

3. The removal of oil and oil products to the sea with the waters of rivers.

4. The influx of oil products with atmospheric precipitation - light oil fractions evaporate from the sea surface and enter the atmosphere, thus about 10 (oil and oil products of the total) enter the World Ocean.

5. Drainage of untreated water from factories and oil depots located on the sea coasts and in ports.

Literature

1 E.A. Sabchenko, I.G. Orlova, V.A. Mikhailova, R.I. Lisovsky - Oil pollution of the Atlantic Ocean // Priroda.-1983.-No5.-p.111.

2 V.V. Izmailov - The impact of petroleum products on the snow and ice cover of the Arctic // Proceedings of the All-Union Geographical Society. -1980 (March-April).

3 D.P. Nikitin, Yu.V. Novikov, Environment and Man - Moscow: Higher School.-1986.-416p.

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Ecological situation in the 21st century

The pollution of world waters has been talked about for a long time. And not only talk - just look at the number of major environmental studies - since the beginning of the 21st century alone, more than a thousand of them have been carried out. By pollution, environmentalists mean the entry into the waters of the World Ocean of such substances that can disrupt the natural biological and inorganic balance of matter and lead to serious changes in the composition or dynamics of the ocean waters.

At the moment, pollution of the oceans has already led to the following consequences:

Ecosystem disruption - in some parts of the ocean, unique ecosystems are disappearing, rare species are being destroyed, the composition of vegetation is changing, and biodiversity is decreasing.
Progressive eutrophication - the water becomes less clean, more and more organic and inorganic impurities appear, the number of animals increases with a decrease in species diversity.
Biota accumulates chemical pollutants - toxic substances.
The result of the complex impact is a decrease in biological productivity. This is noticeable in the declining free catch of fish.
Increasing the concentration of carcinogenic compounds in sea water.
High degree of microbiological pollution of coastal waters.

All of these consequences of pollution of the World Ocean are detrimental not only for the inhabitants of the sea, but also for civilization. The seas are a serious source of resources, ranging from oil to . Therefore, the rational use of water resources is a priority environmental task.

Despite the ability of the world's waters to self-purify, it is not able to cope with the current levels of pollution.

The most dangerous and significant pollution factors:

Oil and oil products.
radioactive substances.
Industrial waste, domestic.
Mainland runoff.
Atmospheric pollution.

The last two points are external sources of pollution, which, although dependent on natural factors, are also associated with human activities.

In the last century, pollution was localized. Most of the pollutants were observed in coastal areas, on the coasts of the continents, near industrial centers, and also near the largest shipping routes. In the last 20 years, the situation has changed - now pollutants are found even in the waters of high latitudes - near the poles. Thus, pollution is widespread and affects all the waters of the oceans.

The main causes of pollution:

Development of mineral and energy resources.
Increasing the extraction of biological resources.
Intensification of economic activity.
Increase in oil production.
Industry growth.

At the moment, the most polluted oceans are considered to be the Pacific and Atlantic, and the most polluted seas are the North, Mediterranean, Baltic, as well as the internal waters of the Persian Gulf.

Oil pollution

It is one of the main contributors to the pollution of the oceans. There are calculations that show that the average annual discharge of oil into the ocean is about 15 million tons. This number includes both unintentional leaks and tanker accidents as well as deliberate runoff from refineries. The measures are now being tightened, but the impact of the time when there were no laws to protect the ocean from tanker washing and runoff from factories is still being felt.

The largest zones of oil pollution are located in coastal waters, as well as along the route of oil tankers. Ecologists note a sharp reduction in the species diversity of flora and fauna in these zones.

The environmental problems of the Pacific and Atlantic are, first of all, the oil film, which, according to various sources, covers from 2 to 4% of the water surface. The waters of these two oceans annually receive 6 million tons of oil and waste from the oil industry - and this is only the waste that has been calculated. Half of the waste comes from the development of offshore fields. Pollution from continental mining enters the water through river runoff.

After oil enters the ocean, the following happens:

A film is formed that covers the surface of the water. The thickness of the film is from fractions of a millimeter to several centimeters. All animals that fall into this film die.
The film turns into an emulsion - a mixture of water and oil.
Oil collects in conglomerates - heavy lumps that remain floating in the surface layer of water.
Oil is swallowed by large fish and mammals such as whales. Thus, oil spreads across the ocean. Fish that have swallowed an oil aggregate either die or continue to live, but are no longer suitable for food after being caught.
The last stage is a decrease in biodiversity, a change in the species structure of the biotope.

The result is a drop in biological productivity. This is especially important for areas whose economy is based on fishing and seafood. The long-term result is an unpredictable change in the biological content of the ocean.

Dumping - dumping waste into the ocean

The dumping or burial of toxic waste in the odes of the oceans is called dumping. This is a common practice in all industrial centers of the planet. Despite the current bans, the runoff from industrial enterprises is growing every year.

On average, dumping accounts for up to 10% of all pollutants entering the ocean.

Basically, pollution occurs in such situations:

Intentional dumping of materials obtained from toxic production.
Discharge of materials during works on the seabed and in the coastal zone.
Construction waste disposal.
Burial of chemicals, explosives, radioactive substances that pose a threat when stored on land.

Waste dissolves in water and accumulates in bottom sediments. After a reset, it is impossible to purify the waters and return them to their original state. Initially, dumping had an ecological justification - the possibility of the World Ocean, which is able to process a certain amount of toxic substances without damage.

Dumping has long been considered a temporary measure. Now it is clear - as long as there is industry, the same amount of waste is being buried in sea waters. The oceans cannot cope with the processing of such an amount of waste, the ecology of sea waters is under threat. At the moment, global waste disposal is one of the most important problems for the world community.

Consequences of irregular waste disposal:

The death of the benthos.
Reducing the growth rate of fish and invertebrates.
Change in species composition.

As a result, the base for the extraction of food resources is shrinking.

Pollution can also be indirect. Thus, chemical industry enterprises located far from coastal areas also affect the state of waters. Pollutants are released into the atmosphere, from where harmful substances, together with precipitation, enter the sea water.

Radioactive contamination is a small fraction of the total contamination, but it can be more dangerous than oil spills. The reason is the ability of radioactive compounds to retain destructive properties for a long time.

Radiation has a detrimental effect on both plants and animals. Radiation exposure is summed up over time, radiation exposure does not pass without a trace. Infection is transmitted through food chains - from one animal to another. As a result, harmful doses of radiation are concentrated in living organisms. So, there are areas where plankton is 1000 times more radioactive than water.

International treaties banning nuclear testing have stopped the massive contamination of the ocean with radioactive waste. But the former burials remained and still affect the life of marine life.

The main ways of accumulation of nuclear waste in the waters of the World Ocean:

Placement of submarines with nuclear deterrents.
The use of nuclear power plants on submarines.
Transportation of waste by water.
The disposal of non-neutralized nuclear waste and nuclear fuel are the main environmental problems of the Arctic Ocean.
Nuclear weapons testing is a problem in the Atlantic Ocean, and, to a greater extent, in the Pacific. Tests lead to both continental contamination and the ingress of radioactive waste into the water area.
Underground tests - radioactive waste enters the ocean with the flow of rivers.

Nuclear waste causes a whole range of problems - not only the ecology of the living suffers, the natural balance of inorganic substances is disturbed.

Pollution of the world's waters is one of the biggest environmental problems of our time. Despite all the measures taken to protect waters from the harmful effects of industry, no serious results have been achieved so far.

1. Features of the behavior of pollutants in the ocean

2. Anthropogenic ecology of the ocean - a new scientific direction in oceanology

3. The concept of assimilation capacity

4. Conclusions from the assessment of the assimilation capacity of the marine ecosystem by pollutants on the example of the Baltic Sea

1 Features of the behavior of pollutants in the ocean. Recent decades have been marked by increased anthropogenic impacts on marine ecosystems as a result of pollution of the seas and oceans. The spread of many pollutants has become local, regional and even global. Therefore, pollution of the seas, oceans and their biota has become a major international problem, and the need to protect the marine environment from pollution is dictated by the requirements of the rational use of natural resources.

Marine pollution is defined as: “The introduction by man, directly or indirectly, of substances or energy into the marine environment (including estuaries) that causes harmful effects such as damage to living resources, danger to human health, interference with marine activities, including fishing, deterioration of sea water quality and reduction of its useful properties. This list includes substances with toxic properties, discharges of heated waters (thermal pollution), pathogenic microbes, solid wastes, suspended solids, nutrients and some other forms of anthropogenic impacts.

The most urgent problem in our time has become the problem of chemical pollution of the ocean.

The sources of pollution of the ocean and seas include the following:

Discharge of industrial and economic waters directly into the sea or with river runoff;

Intake from land of various substances used in agriculture and forestry;

Intentional dumping of pollutants at sea; leakage of various substances during ship operations;

Accidental releases from ships or subsea pipelines;

Development of minerals on the seabed;

Transport of pollutants through the atmosphere.

The list of pollutants received by the ocean is extremely extensive. All of them differ in the degree of toxicity and the scale of distribution - from coastal (local) to global.

More and more pollutants are being found in the oceans. The most dangerous for organisms organochlorine compounds, polyaromatic hydrocarbons and some others are becoming globally widespread. They have a high bioaccumulative capacity, a sharp toxic and carcinogenic effect.

The steady increase in the total impact of many pollution sources leads to progressive eutrophication of coastal marine zones and microbiological water pollution, which significantly complicates the use of water for various human needs.

Oil and oil products. Oil is a viscous oily liquid, usually dark brown in color and with low fluorescence. Oil consists mainly of saturated aliphatic and hydroaromatic hydrocarbons (from C 5 to C 70) and contains 80-85% C, 10-14% H, 0.01-7% S, 0.01% N and 0-7% O 2.

The main components of oil - hydrocarbons (up to 98%) - are divided into four classes.

1. Paraffins (alkanes) (up to 90% of the total composition of oil) are stable saturated compounds C n H 2n-2, the molecules of which are expressed by a straight or branched (isoalkanes) chain of carbon atoms. Paraffins include the gases methane, ethane, propane and others, compounds with 5-17 carbon atoms are liquids, and those with a large number of carbon atoms are solids. Light paraffins have maximum volatility and solubility in water.

2. Cycloparaffins. (naphthenes)-saturated cyclic compounds C n H 2 n with 5-6 carbon atoms in the ring (30-60% of the total oil composition). In addition to cyclopentane and cyclohexane, bicyclic and polycyclic naphthenes are found in oil. These compounds are very stable and difficult to biodegrade.

3. Aromatic hydrocarbons (20-40% of the total composition of oil) - unsaturated cyclic compounds of the benzene series, containing 6 carbon atoms in the ring less than the corresponding naphthenes. The carbon atoms in these compounds can also be replaced by alkyl groups. Oil contains volatile compounds with a molecule in the form of a single ring (benzene, toluene, xylene), then bicyclic (naphthalene), tricyclic (anthracene, phenanthrene) and polycyclic (for example, pyrene with 4 rings) hydrocarbons.

4. Olephips (alkenes) (up to 10% of the total composition of oil) are unsaturated non-cyclic compounds with one or two hydrogen atoms at each carbon atom in a molecule that has a straight or branched chain.

Depending on the field, oils differ significantly in their composition. Thus, Pennsylvania and Kuwaiti oils are classified as paraffinic, Baku and California - mainly naphthenic, the rest of the oils - intermediate types.

Oil also contains sulfur-containing compounds (up to 7% sulfur), fatty acids (up to 5% oxygen), nitrogen compounds (up to 1% nitrogen) and some organometallic derivatives (with vanadium, cobalt and nickel).

Quantitative analysis and identification of petroleum products in the marine environment present significant difficulties not only because of their multicomponent nature and different forms of existence, but also due to the natural background of hydrocarbons of natural and biogenic origin. For example, about 90% of low molecular weight hydrocarbons such as ethylene dissolved in the surface waters of the ocean is associated with the metabolic activity of organisms and the decay of their residues. However, in areas of intense pollution, the level of content of such hydrocarbons increases by 4-5 orders of magnitude.

Hydrocarbons of biogenic and petroleum origin, according to experimental studies, have a number of differences.

1. Oil is a more complex mixture of hydrocarbons with a wide range of structures and relative molecular weights.

2. Oil contains several homologous series, in which neighboring members usually have equal concentrations. For example, in the C 12 -C 22 series of alkanes, the ratio of even and odd members is equal to one, while biogenic hydrocarbons in the same series contain predominantly odd members.

3. Oil contains a wider range of cycloalkanes and aromatics. Many compounds such as mono-, di-, tri- and tetramethylbenzenes are not found in marine organisms.

4. Oil contains numerous naphtheno-aromatic hydrocarbons, various heterocompounds (containing sulfur, nitrogen, oxygen, metal ions), heavy asphalt-like substances - all of them are practically absent in organisms.

Oil and oil products are the most common pollutants in the oceans.

The routes of entry and forms of existence of petroleum hydrocarbons are diverse (dissolved, emulsified, filmy, solid). M. P. Nesterova (1984) notes the following ways of admission:

discharges in ports and near-port water areas, including losses when loading bunkers of tankers (17%~);

Discharge of industrial waste and sewage (10%);

Storm drains (5%);

Disasters of ships and drilling rigs at sea (6%);

Offshore drilling (1%);

Atmospheric fallout (10%)",

Removal by river runoff in all variety of forms (28%).

Discharges into the sea of washing, ballast and bilge water from ships (23%);

The greatest losses of oil are associated with its transportation from production areas. Emergencies, discharge of washing and ballast water overboard by tankers - all this leads to the presence of permanent pollution fields along sea routes.

The property of oils is their fluorescence under ultraviolet irradiation. The maximum fluorescence intensity is observed in the wavelength range 440-483 nm.

The difference in the optical characteristics of oil films and sea water allows remote detection and evaluation of oil pollution on the sea surface in the ultraviolet, visible and infrared parts of the spectrum. For this, passive and active methods are used. Large masses of oil from land enter the seas along rivers, with domestic and storm drains.

The fate of oil spilled into the sea is determined by the sum of the following processes: evaporation, emulsification, dissolution, oxidation, formation of oil aggregates, sedimentation and biodegradation.

Getting into the marine environment, oil first spreads in the form of a surface film, forming slicks of various thicknesses. By the color of the film, you can approximately estimate its thickness. The oil film changes the intensity and spectral composition of the light penetrating into the water mass. The light transmission of thin films of crude oil is 1-10% (280 nm), 60-70% (400 nm). An oil film with a thickness of 30-40 microns completely absorbs infrared radiation.

In the early days of oil slicks, the evaporation of hydrocarbons was of great importance. According to observations, up to 25% of light oil fractions evaporate in 12 hours; at a water temperature of 15 °C, all hydrocarbons up to C 15 evaporate in 10 days (Nesterova, Nemirovskaya, 1985).

All hydrocarbons have a low solubility in water, which decreases with increasing number of carbon atoms in the molecule. About 10 mg of compounds with C 6, 1 mg of compounds with C 8 and 0.01 mg of compounds with C 12 are dissolved in 1 liter of distilled water. For example, at an average temperature of sea water, the solubility of benzene is 820 µg/l, toluene - 470, pentane - 360, hexane - 138 and heptane - 52 µg/l. Soluble components, the content of which in crude oil does not exceed 0.01%, are the most toxic for aquatic organisms. They also include substances such as benzo(a)pyrene.

When mixed with water, oil forms two types of emulsions: direct "oil in water" and reverse "water in oil". Direct emulsions, composed of oil droplets with a diameter of up to 0.5 microns, are less stable and are especially characteristic of oils containing surfactants. After removal of volatile and soluble fractions, residual oil often forms viscous inverse emulsions, which are stabilized by high-molecular compounds such as resins and asphaltenes and contain 50-80% water (“chocolate mousse”). Under the influence of abiotic processes, the viscosity of the "mousse" increases and it begins to stick together into aggregates - oil lumps ranging in size from 1 mm to 10 cm (usually 1-20 mm). The aggregates are a mixture of high molecular weight hydrocarbons, resins and asphaltenes. Oil losses for the formation of aggregates are 5-10%. Highly viscous structured formations - "chocolate mousse" and oil lumps - can remain on the sea surface for a long time, be carried by currents, be thrown ashore and settle to the bottom. Oil lumps are often populated by periphyton (blue-green and diatoms, barnacles and other invertebrates).

Pesticides constitute an extensive group of artificially created substances used to control pests and plant diseases. Depending on the intended purpose, pesticides are divided into the following groups: insecticides - to combat harmful insects, fungicides and bactericides - to combat fungal and bacterial plant diseases, herbicides - against weeds, etc. According to economists' calculations, each ruble spent for the chemical protection of plants from pests and diseases, ensures the preservation of the crop and its quality in the cultivation of grain and vegetable crops by an average of 10 rubles, technical and fruit crops - up to 30 rubles. At the same time, environmental studies have established that pesticides, destroying crop pests, cause great harm to many beneficial organisms and undermine the health of natural biocenoses. Agriculture has long faced the challenge of shifting from chemical (polluting) to biological (environmentally friendly) methods of pest control.

Currently, more than 5 million tons of pesticides enter the world market annually. About 1.5 million tons of these substances have already entered the terrestrial and marine ecosystems by aeolian or aquatic routes. The industrial production of pesticides is accompanied by the appearance of a large number of by-products that pollute wastewater.

In the aquatic environment, representatives of insecticides, fungicides and herbicides are more common than others.

Synthesized insecticides are divided into three main groups: organochlorine, organophosphorus and carbamates.

Organochlorine insecticides are obtained by chlorination of aromatic or heterocyclic liquid hydrocarbons. These include DDT (dichlorodiphenyltrichloroethane) and its derivatives, in whose molecules the stability of aliphatic and aromatic groups increases in the joint presence, various chlorinated derivatives of cyclodiene (eldrin, dil-drin, heptachlor, etc.), as well as numerous isomers of hexachlorocyclohexane (in -HCCH), of which lindane is the most dangerous. These substances have a half-life of up to several decades and are very resistant to biodegradation.

In the aquatic environment, polychlorinated biphenyls (PCBs) are often found - DDT derivatives without an aliphatic part, numbering 210 theoretical homologues and isomers.

Over the past 40 years, more than 1.2 million tons of PCBs have been used in the production of plastics, dyes, transformers, capacitors, etc. Polychlorinated biphenyls enter the environment as a result of industrial wastewater discharges and solid waste incineration in landfills. The latter source delivers PCBs to the atmosphere, from where they fall out with atmospheric precipitation in all regions of the globe. Thus, in snow samples taken in Antarctica, the content of PCBs was 0.03-1.2 ng/l.

Organophosphate pesticides are esters of various alcohols of phosphoric acid or one of its derivatives, thiophosphoric. This group includes modern insecticides with a characteristic selectivity of action in relation to insects. Most organophosphates are subject to fairly rapid (within a month) biochemical degradation in soil and water. More than 50,000 active substances have been synthesized, of which parathion, malathion, phosalong, and dursban are especially famous.

Carbamates are, as a rule, esters of n-metacarbamic acid. Most of them also have selectivity of action.

As fungicides used to combat fungal diseases of plants, copper salts and some mineral sulfur compounds were previously used. Then, organomercury substances such as chlorinated methylmercury were widely used, which, due to its extreme toxicity to animals, was replaced by methoxyethylmercury and phenylmercury acetates.

The group of herbicides includes derivatives of phenoxyacetic acid, which have a strong physiological effect. Triazines (for example, simazine) and substituted ureas (monuron, diuron, pichloram) constitute another group of herbicides, quite well soluble in water and stable in soils. Pichloram is the strongest of all herbicides. For the complete destruction of some plant species, only 0.06 kg of this substance per 1 ha is required.

DDT and its metabolites, PCBs, HCH, deldrin, tetrachlorophenol and others are constantly found in the marine environment.

Synthetic surfactants. Detergents (surfactants) belong to an extensive group of substances that lower the surface tension of water. They are part of synthetic detergents (CMC), widely used in everyday life and industry. Together with wastewater, surfactants enter the continental surface waters and the marine environment. Synthetic detergents contain sodium polyphosphates, in which detergents are dissolved, as well as a number of additional ingredients that are toxic to aquatic organisms: fragrances, bleaching agents (persulphates, perborates), soda ash, carboxymethyl cellulose, sodium silicates and others.

The molecules of all surfactants consist of hydrophilic and hydrophobic parts. The hydrophilic part is carboxyl (COO -), sulfate (OSO 3 -) and sulfonate (SO 3 -) groups, as well as accumulations of residues with groups -CH 2 -CH 2 -O-CH 2 -CH 2 - or groups containing nitrogen and phosphorus. The hydrophobic part usually consists of a straight line, including 10-18 carbon atoms, or a branched paraffin chain, from a benzene or naphthalene ring with alkyl radicals.

Depending on the nature and structure of the hydrophilic part of the surfactant molecules, they are divided into anionic (the organic ion is negatively charged), cationic (the organic ion is positively charged), amphoteric (displaying cationic properties in an acidic solution, and anionic in an alkaline solution) and nonionic. The latter do not form ions in water. Their solubility is due to functional groups that have a strong affinity for water and the formation of a hydrogen bond between water molecules and oxygen atoms included in the polyethylene glycol radical of the surfactant.

The most common among the surfactants are anionic substances. They account for more than 50% of all surfactants produced in the world. The most common are alkylarylsulfonates (sulfonols) and alkyl sulfates. Sulfonol molecules contain an aromatic ring, the hydrogen atoms of which are replaced by one or more alkyl groups, and a sulfuric acid residue as a solvating group. Numerous alkylbenzene sulfonates and alkylnaphthalenesulfonates are often used in the manufacture of various household and industrial CMCs.

The presence of surfactants in industrial wastewater is associated with their use in such processes as flotation beneficiation of ores, separation of chemical technology products, production of polymers, improvement of conditions for drilling oil and gas wells, and equipment corrosion control.

In agriculture, surfactants are used as part of pesticides. With the help of surfactants, liquid and powdered toxic substances that are insoluble in water, but soluble in organic solvents, are emulsified, and many surfactants themselves have insecticidal and herbicidal properties.

Carcinogenic substances- these are chemically homogeneous compounds that exhibit transforming activity and are capable of causing carcinogenic, teratogenic (violation of embryonic development processes) or mutagenic changes in organisms. Depending on the exposure conditions, they can lead to growth inhibition, accelerated aging, toxicogenesis, disruption of individual development, and changes in the gene pool of organisms. Substances with carcinogenic properties include chlorinated aliphatic hydrocarbons with a short sliver of carbon atoms in the molecule, vinyl chloride, pesticides and, especially, polycyclic aromatic hydrocarbons (PAHs). The latter are high molecular weight organic compounds, in the molecules of which the benzene ring is the main element of the structure. Numerous unsubstituted PAHs contain from 3 to 7 benzene rings in the molecule, interconnected in various ways. There are also a large number of polycyclic structures containing a functional group either in the benzene ring or in the side chain. This halogen-, amino-, sulfo-, nitro derivatives, as well as alcohols, aldehydes, esters, ketones, acids, quinones and other aromatic compounds.

The solubility of PAHs in water is low and decreases with increasing molecular weight: from 16 100 µg/l (acenaphthylene) to 0.11 µg/l (3,4-benzpyrene). The presence of salts in water has practically no effect on the solubility of PAHs. However, in the presence of benzene, oil, oil products, detergents, and other organic substances, the solubility of PAHs sharply increases. Of the group of unsubstituted PAHs, 3,4-benzpyrene (BP) is the best known and widespread under natural conditions.

Natural and anthropogenic processes can serve as sources of PAHs in the environment. The concentration of BP in volcanic ash is 0.3-0.9 µg/kg. This means that 1.2-24 tons of BP per year can enter the environment with ash. Therefore, the maximum amount of PAHs in modern bottom sediments of the World Ocean (more than 100 μg/kg of dry matter mass) was found in tectonically active zones subject to deep thermal action.

Some marine plants and animals are reported to be able to synthesize PAHs. In algae and sea grasses near the western coast of Central America, the content of BP reaches 0.44 µg/g, and in some crustaceans in the Arctic, 0.23 µg/g. Anaerobic bacteria produce up to 8.0 μg of BP from 1 g of plankton lipid extracts. On the other hand, there are special types of marine and soil bacteria that decompose hydrocarbons, including PAHs.

According to L. M. Shabad (1973) and A. P. Ilnitsky (1975), the background concentration of BP created as a result of the synthesis of BP by plant organisms and volcanic activity is: in soils 5-10 µg/kg (dry matter), in plants 1-5 µg/kg, in freshwater reservoirs 0.0001 µg/l. Accordingly, gradations of the degree of pollution of environmental objects are also derived (Table 1.5).

The main anthropogenic sources of PAHs in the environment are the pyrolysis of organic substances during the combustion of various materials, wood, and fuel. The pyrolytic formation of PAHs occurs at a temperature of 650-900 °C and a lack of oxygen in the flame. The formation of BP was observed during the pyrolysis of wood with a maximum yield at 300–350°C (Dikun, 1970).

According to M. Suess (G976), the global emission of BP in the 70s was about 5000 tons per year, with 72% coming from industry and 27% from all types of open burning.

Heavy metals(mercury, lead, cadmium, zinc, copper, arsenic and others) are among the common and highly toxic pollutants. They are widely used in various industrial productions, therefore, despite the treatment measures, the content of heavy metal compounds in industrial wastewater is quite high. Large masses of these compounds enter the ocean through the atmosphere. Mercury, lead and cadmium are the most dangerous for marine biocenoses.

Mercury is transported to the ocean with continental runoff and through the atmosphere. During the weathering of sedimentary and igneous rocks, 3.5 thousand tons of mercury are released annually. The composition of atmospheric dust contains about 12 thousand tons of mercury, and a significant part of anthropogenic origin. As a result of volcanic eruptions and atmospheric precipitation, 50 thousand tons of mercury annually enter the ocean surface, and 25-150 thousand tons of mercury during degassing of the lithosphere. About half of the annual industrial production of this metal (9-10 thousand tons / year) in various ways falls into the ocean. The content of mercury in coal and oil is on average 1 mg/kg; therefore, when burning fossil fuels, the World Ocean receives more than 2 thousand tons/year. The annual production of mercury exceeds 0.1% of its total content in the World Ocean, but the anthropogenic influx already exceeds the natural removal by rivers, which is typical for many metals.

In areas polluted by industrial wastewater, the concentration of mercury in solution and suspension is greatly increased. At the same time, some benthic bacteria convert chlorides into highly toxic (mono- and di-) methylmercury CH 3 Hg. Contamination of seafood has repeatedly led to mercury poisoning of the coastal population. By 1977, there were 2,800 victims of Minamata disease in Japan. The reason was the waste of enterprises for the production of vinyl chloride and acetaldehyde, in which mercury chloride was used as a catalyst. Insufficiently treated wastewater from enterprises entered the Minamata Bay.

Lead is a typical trace element found in all components of the environment: in rocks, soils, natural waters, the atmosphere, and living organisms. Finally, lead is actively dissipated into the environment during human activities. These are emissions from industrial and domestic effluents, from smoke and dust from industrial enterprises, from exhaust gases from internal combustion engines.

According to V.V. Dobrovolsky (1987), the redistribution of lead masses between land and the World Ocean is as follows. C. river runoff at an average lead concentration in water of 1 μg / l into the ocean of water-soluble lead is carried out about 40 10 3 t / year, in the solid phase of river suspensions about 2800-10 3 t / year, in fine organic detritus - 10 10 3 t /year. If we take into account that more than 90% of river suspensions settle in a narrow coastal strip of the shelf and a significant part of water-soluble metal compounds are captured by iron oxide gels, then as a result, the ocean pelagial receives only about (200-300) 10 3 tons in the composition of fine suspensions and (25- 30) 10 3 tons of dissolved compounds.

The migration flow of lead from the continents to the ocean goes not only with river runoff, but also through the atmosphere. With continental dust, the ocean receives (20-30)-10 3 tons of lead per year. Its entry to the ocean surface with liquid atmospheric precipitation is estimated at (400-2500) 10 3 t/year at a concentration in rainwater of 1-6 µg/l. The sources of lead entering the atmosphere are volcanic emissions (15-30 t/year in the composition of pelitic eruption products and 4 10 3 t/year in submicron particles), volatile organic compounds from vegetation (250-300 t/year), combustion products from fires ((6-7) 10 3 t/year) and modern industry. Lead production increased from 20-103 tons/year at the beginning of the 19th century. up to 3500 10 3 t/year by the beginning of the 80s of the XX century. Modern release of lead into the environment with industrial and household waste is estimated at (100-400) 10 3 t/year.

Cadmium, whose world production in the 1970s reached 15 10 3 tons/year, also enters the ocean with river runoff and through the atmosphere. The volume of atmospheric removal of cadmium, according to various estimates, is (1.7-8.6) 10 3 t/year.

Discharge of waste into the sea for the purpose of disposal (dumping). Many countries with access to the sea undertake marine disposal of various materials and substances, in particular soil excavated during dredging, drill cuttings, industrial waste, construction debris, solid waste, explosives and chemicals, radioactive waste, etc. Volume landfills is about 10% of the total mass of pollutants entering the oceans. So, from 1976 to 1980, more than 150 million tons of various wastes were dumped annually for the purpose of burial, which defines the concept of "dumping".

The basis for dumping in the sea is the ability of the marine environment to process a large amount of organic and inorganic substances without much damage to water quality. However, this ability is not unlimited. Therefore, dumping is considered as a forced measure, a temporary tribute to the imperfection of technology by society. Hence, the development and scientific substantiation of ways to regulate waste discharges into the sea are of particular importance.

Industrial sludge contains a variety of organic substances and heavy metal compounds. Household garbage contains on average (on a dry matter basis) 32-40% organic matter, 0.56% nitrogen, 0.44% phosphorus, 0.155% zinc, 0.085% lead, 0.001% cadmium, 0.001 mercury. Sludge from municipal wastewater treatment plants contains (per dry matter weight) up to. 12% humic substances, up to 3% total nitrogen, up to 3.8% phosphates, 9-13% fats, 7-10% carbohydrates and are contaminated with heavy metals. Bottom grab materials have a similar composition.

During the discharge, when the material passes through the water column, part of the pollutants goes into solution, changing the quality of the water, while the other part is sorbed by suspended particles and goes into bottom sediments. At the same time, the turbidity of the water increases. The presence of organic substances often leads to the rapid consumption of oxygen in water and often to its complete disappearance, the dissolution of suspensions, the accumulation of metals in dissolved form, and the appearance of hydrogen sulfide. The presence of a large amount of organic matter creates a stable reducing environment in the soil, in which a special type of interstitial water appears, containing hydrogen sulfide, ammonia, and metal ions in reduced form. In this case, the reduction of sulfates and nitrates, phosphates are released.

Neuston, pelagic and benthos organisms are affected to varying degrees by the discharged materials. In the case of the formation of surface films containing petroleum hydrocarbons and surfactants, gas exchange at the air-water interface is disrupted. This leads to the death of invertebrate larvae, fish larvae and fry, and causes an increase in the number of oil-oxidizing and pathogenic microorganisms. The presence of a polluting suspension in the water worsens the conditions of nutrition, respiration and metabolism of hydrobionts, reduces the growth rate, and inhibits the puberty of planktonic crustaceans. Pollutants entering the solution can accumulate in the tissues and organs of hydrobionts and have a toxic effect on them. The dumping of dumping materials to the bottom and prolonged increased turbidity of the bottom water lead to filling and death from suffocation of attached and inactive forms of benthos. In surviving fish, mollusks and crustaceans, the growth rate is reduced due to the deterioration of feeding and breathing conditions. The species composition of the benthic community often changes.

When organizing a system for controlling waste discharges into the sea, the definition of dumping areas, taking into account the properties of materials and the characteristics of the marine environment, is of decisive importance. The necessary criteria for solving the problem are contained in the "Convention for the Prevention of Marine Pollution by Dumping of Wastes and Other Materials" (London Convention on Dumping, 1972). The main requirements of the Convention are as follows.

1. Assessment of the quantity, condition and properties (physical, chemical, biochemical, biological) of discharged materials, their toxicity, stability, tendency to accumulation and biotransformation in the aquatic environment and marine organisms. Using the possibilities of neutralization, neutralization and recycling of waste.

2. Selection of areas of discharge, taking into account the requirements of maximum dilution of substances, their minimum spread beyond the discharge, a favorable combination of hydrological and hydrophysical conditions.

3. Ensuring remoteness of discharge areas from fish feeding and spawning areas, from habitats of rare and sensitive species of hydrobionts, from recreation and economic use areas.

Technogenic radionuclides. The ocean is characterized by natural radioactivity due to the presence in it of 40 K, 87 Rb, 3 H, 14 C, as well as radionuclides of the uranium and thorium series. More than 90% of the natural radioactivity of ocean water is 40 K, which is 18.5-10 21 Bq. The unit of activity in the SI system is the becquerel (Bq), equal to the activity of an isotope in which 1 decay event occurs in 1 s. Previously, the off-system unit of radioactivity, curie (Ci), was widely used, corresponding to the activity of an isotope in which 3.7-10 10 decay events occur in 1 s.

Radioactive substances of technogenic origin, mainly fission products of uranium and plutonium, began to enter the ocean in large quantities after 1945, i.e., from the beginning of nuclear weapons testing and the widespread development of the industrial production of fissile materials and radioactive nuclides. Three groups of sources are identified: 1) testing of nuclear weapons, 2) dumping of radioactive waste, 3) accidents of ships with nuclear engines and accidents associated with the use, transportation and production of radionuclides.

Many radioactive isotopes with a short half-life, although found in water and marine organisms after an explosion, are almost never found in global radioactive fallout. Here, first of all, 90 Sr and 137 Cs are present with a half-life of about 30 years. The most dangerous radionuclide from the unreacted remains of nuclear charges is 239 Pu (T 1/2 = 24.4-10 3 years), which is very poisonous as a chemical substance. As fission products 90 Sr and 137 Cs decay, it becomes the main contaminant. By the time of the moratorium on atmospheric tests of nuclear weapons (1963), the activity of 239 Pu in the environment was 2.5-10 16 Bq.

A separate group of radionuclides is formed by 3 H, 24 Na, 65 Zn, 59 Fe, 14 C, 31 Si, 35 S, 45 Ca, 54 Mn, 57.60 Co and others arising from the interaction of neutrons with structural elements and the environment. The main products of nuclear reactions with neutrons in the marine environment are the radioisotopes of sodium, potassium, phosphorus, chlorine, bromine, calcium, manganese, sulfur, and zinc, which originate from elements dissolved in sea water. This is induced activity.

Most of the radionuclides that enter the marine environment have analogs that are constantly present in water, such as 239 Pu, 239 Np, 99 T C) transplutonium are not typical for the composition of sea water, and the living matter of the ocean must adapt to them anew.

As a result of the processing of nuclear fuel, a significant amount of radioactive waste appears in liquid, solid and gaseous forms. The bulk of the waste is radioactive solutions. Given the high cost of processing and storing concentrates in special storage facilities, some countries choose to dump waste into the ocean with river runoff or dump it in concrete blocks on the bottom of deep ocean trenches. For the radioactive isotopes Ar, Xe, Em and T, reliable methods of concentration have not yet been developed, so they can enter the oceans with rain and sewage.

During the operation of nuclear power plants on surface and underwater vessels, of which there are already several hundred, about 3.7-10 16 Bq with ion-exchange resins, about 18.5-10 13 Bq with liquid waste and 12.6-10 13 Bq due to leaks. Emergencies also make a significant contribution to ocean radioactivity. To date, the amount of radioactivity introduced into the ocean by man does not exceed 5.5-10 19 Bq, which is still small compared to the natural level (18.5-10 21 Bq). However, the concentration and unevenness of radionuclide fallout creates a serious danger of radioactive contamination of water and hydrobionts in certain areas of the ocean.

2 Anthropogenic ocean ecology–new scientific direction in oceanology. As a result of anthropogenic impact, additional environmental factors appear in the ocean that contribute to the negative evolution of marine ecosystems. The discovery of these factors stimulated the development of extensive fundamental research in the World Ocean and the emergence of new scientific directions. Among them is the anthropogenic ecology of the ocean. This new direction is designed to study the mechanisms of organisms' response to anthropogenic impacts at the level of a cell, organism, population, biocenosis, ecosystem, as well as to study the features of interactions between living organisms and the environment in changed conditions.

The object of study of the anthropogenic ecology of the ocean is the change in the ecological characteristics of the ocean, primarily those changes that are important for the ecological assessment of the state of the biosphere as a whole. These studies are based on a comprehensive analysis of the state of marine ecosystems, taking into account geographic zoning and the degree of anthropogenic impact.

The anthropogenic ecology of the ocean uses the following methods of analysis for its own purposes: genetic (assessment of carcinogenic and mutagenic hazards), cytological (study of the cellular structure of marine organisms in a normal and pathological state), microbiological (study of the adaptation of microorganisms to toxic pollutants), ecological (knowledge of the patterns of formation and development of populations and biocenoses in specific habitat conditions in order to predict their state in changing environmental conditions), ecological and toxicological (study of the response of marine organisms to the effects of pollution and determination of critical concentrations of pollutants), chemical (study of the entire complex of natural and anthropogenic chemicals in marine environment).

The main task of anthropogenic ocean ecology is to develop scientific bases for determining the critical levels of pollutants in marine ecosystems, assessing the assimilation capacity of marine ecosystems, normalizing anthropogenic impacts on the World Ocean, and also creating mathematical models of environmental processes to predict environmental situations in the ocean.

Knowledge about the most important ecological phenomena in the ocean (such as production-destruction processes, the passage of biogeochemical cycles of pollutants, etc.) is limited by a lack of information. This makes it difficult to predict the ecological situation in the ocean and the implementation of environmental protection measures. At present, of particular importance is the implementation of ecological monitoring of the ocean, the strategy of which is focused on long-term observations in certain areas of the ocean with the aim of creating a data bank covering the global transformation of ocean ecosystems.

3 The concept of assimilation capacity. According to the definition of Yu. A. Israel and A. V. Tsyban (1983, 1985), the assimilation capacity of the marine ecosystem A i for this pollutant i(or the sum of pollutants) and for the m-th ecosystem is the maximum dynamic capacity of such a quantity of pollutants (in terms of the entire zone or volume unit of the marine ecosystem) that can be accumulated, destroyed, transformed (by biological or chemical transformations) per unit of time ) and removed due to the processes of sedimentation, diffusion or any other transfer outside the volume of the ecosystem without disturbing its normal functioning.

The total removal (A i) of a pollutant from a marine ecosystem can be written as

where K i is the safety factor reflecting the environmental conditions of the pollution process in different zones of the marine ecosystem; τ i - residence time of the pollutant in the marine ecosystem.

This condition is met at , where C 0 i is the critical concentration of the pollutant in sea water. Hence, the assimilation capacity can be estimated by formula (1) at ;.

All quantities included in the right side of equation (1) can be directly measured according to the data obtained in the process of long-term integrated studies of the state of the marine ecosystem. At the same time, the sequence of determining the assimilation capacity of a marine ecosystem for specific pollutants includes three main stages: 1) calculating the balances of the mass and lifetime of pollutants in the ecosystem, 2) analyzing the biotic balance in the ecosystem, and 3) assessing the critical concentrations of the impact of pollutants (or environmental MPCs). ) on the functioning of the biota.

To address the issues of environmental regulation of anthropogenic impacts on marine ecosystems, the calculation of the assimilation capacity is the most representative, since it takes into account the assimilation capacity, the maximum permissible environmental load (MPEL) of the pollutant reservoir is calculated quite simply. So, in the stationary mode of pollution of the reservoir, PDEN will be equal to the assimilation capacity.

4 Conclusions from the assessment of the assimilation capacity of the marine ecosystem by pollutants on the example of the Baltic Sea. Using the example of the Baltic Sea, the values of assimilation capacity for a number of toxic metals (Zn, Сu, Pb, Cd, Hg) and organic substances (PCBs and BP) were calculated (Izrael, Tsyban, Venttsel, Shigaev, 1988).

The average concentrations of toxic metals in sea water turned out to be one or two orders of magnitude lower than their threshold doses, while the concentrations of PCBs and BP were only an order of magnitude lower. Hence, the safety factors for PCBs and BP turned out to be lower than for metals. At the first stage of the work, the authors of the calculation, using materials from long-term ecological studies in the Baltic Sea and literary sources, determined the concentrations of pollutants in the ecosystem components, the rates of biosedimentation, the fluxes of substances at the boundaries of the ecosystem, and the activity of microbial destruction of organic substances. All this made it possible to draw up balances and calculate the “lifetime” of the considered substances in the ecosystem. The "lifetime" of metals in the Baltic ecosystem turned out to be quite short for lead, cadmium and mercury, somewhat longer for zinc, and maximum for copper. The "lifetime" of PCBs and benzo(a)pyrene is 35 and 20 years, which determines the need to introduce a system of genetic monitoring of the Baltic Sea.

At the second stage of research, it was shown that the most sensitive element of the biota to pollutants and changes in the ecological situation are planktonic microalgae, and therefore, the process of primary production of organic matter should be chosen as the “target” process. Therefore, the threshold doses of pollutants established for phytoplankton are applied here.

Estimates of the assimilation capacity of the zones of the open part of the Baltic Sea show that the existing sink of zinc, cadmium and mercury, respectively, is 2, 20 and 15 times less than the minimum values of the assimilation capacity of the ecosystem for these metals and does not pose a direct danger to primary production. At the same time, the supply of copper and lead already exceeds their assimilation capacity, which requires the introduction of special measures to limit the flow. The current supply of BP has not yet reached the minimum value of the assimilation capacity, while PCBs exceed it. The latter points to the urgent need to further reduce PCB discharges into the Baltic Sea.