Ocean waters are rapidly becoming polluted. A huge amount of “dirt” is carried into the ocean from land by rivers and sewage. More than 30% of the ocean surface is covered with an oil film that is destructive to plankton. The destruction of plankton, that is, protozoa and crustaceans passively floating in water, led to a reduction in the food supply for nekton and reduced its quantity, and, consequently, reduced fish production.
The environmental consequences of pollution of the World Ocean are expressed in the following processes and phenomena:
Violation of ecosystem stability;
Progressive eutrophication;
The emergence 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.
The industrial use of the World Ocean has led to colossal pollution, and currently this problem is one of the global ones facing all of humanity. Over the past 20 years, ocean pollution has become catastrophic.
Not the least role in this was played by the opinion about the ocean’s capabilities for self-purification.
The most dangerous pollution for the ocean is: pollution from oil and petroleum products, radioactive substances, industrial and household waste, and chemical fertilizers. However, there are also powerful external sources of pollution - atmospheric flows and continental runoff. As a result, today we can state the presence of pollutants not only in areas adjacent to continents and in areas of intense shipping, but also in open parts of the oceans, including the high latitudes of the Arctic and Antarctic. It should be noted that pollution of soil, water or atmosphere also ultimately comes down to pollution of the World Ocean, since as a result all toxic substances enter it.
The rapid development of engineering and technology has led to the involvement of ocean resources in economic circulation, and its problems have become global in nature. There are a lot of these problems. They are associated with ocean pollution, a decrease in its biological productivity, and the development of mineral and energy resources. Ocean use has particularly increased in recent years, dramatically increasing the pressure on the ocean. Intensive economic activity has led to increasing water pollution. Accidents of oil tankers, drilling platforms, and the discharge of oil-contaminated water from ships have a particularly detrimental effect on the environmental situation in the World Ocean. The marginal seas are especially polluted: the North, Baltic, Mediterranean, and Persian Gulf.
According to experts, about 15 million tons of oil enter the World Ocean every year. This is due to the movements of oil tankers. In the past, the practice of flushing the holds of tankers was widespread, resulting in the release of huge quantities of oil into the ocean.
Coastal waters are mainly affected by a large number of sources of pollution: from industrial waste and sewage to intense marine traffic. This contributes to the reduction of ocean flora and fauna, and creates a serious danger for humans in the form of numerous diseases
Oil pollution of the World Ocean 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 film. Up to 6 million tons of petroleum hydrocarbons enter sea waters annually. Almost half of this amount is associated with transportation and offshore development. Continental oil pollution enters the ocean through river runoff.
In the ocean, oil pollution comes in many forms. It can cover the surface of the water in a thin film, and during spills the thickness of the oil coating can initially be several centimeters. Over time, an emulsion of oil in water or water in oil is formed. Later, lumps of the heavy fraction of oil, oil aggregates, appear that can float on the surface of the sea for a long time. Various small animals are attached to the floating lumps of fuel oil, which fish and baleen whales readily feed on. Together with them they swallow oil. Some fish die from this, others become completely saturated with oil and become unsuitable for consumption due to their unpleasant smell and taste. All components of oil are toxic to marine organisms. Oil affects the community structure of marine animals. Oil pollution changes the ratio of species and reduces their diversity. Thus, microorganisms that feed on petroleum hydrocarbons develop abundantly, and the biomass of these microorganisms is toxic to many marine inhabitants.
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 falling. Oil has another unpleasant side effect. Its hydrocarbons are capable of dissolving a number of other pollutants, such as pesticides and heavy metals, which, together with oil, are concentrated in the surface layer and further poison it. The largest quantities of oil are concentrated in a thin near-surface layer of sea water, which plays a particularly important role for various aspects of ocean life. Surface oil films disrupt gas exchange between the atmosphere and the ocean. The processes of dissolution and release of oxygen, carbon dioxide, heat exchange undergo changes, and the reflectivity of sea water changes. Chlorinated hydrocarbons, widely used as means of controlling agricultural and forestry pests and carriers of infectious diseases, have been entering the World Ocean along with river runoff and through the atmosphere for many decades. DDT (a chemical widely used in the 50-60s of the 20th century for pest control. A very persistent compound that can accumulate in the environment, pollute it and disrupt the biological balance in nature. Banned everywhere in the 70s) and its derivatives , polychlorinated biphenyls and other persistent 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, and seabirds. Being substances of completely artificial origin, they do not have their “consumers” among microorganisms and therefore almost do not decompose in natural conditions, but only accumulate in the World Ocean. At the same time, they are acutely toxic and affect the hematopoietic system and heredity.
Along with river runoff, heavy metals also enter the ocean, many of which have toxic properties. The total river flow is 46 thousand km 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 levels of pollution.
The atmosphere also plays a significant role in the pollution of the World Ocean. For example, up to 30% of all mercury and 50% of lead entering the ocean each year is transported through the atmosphere. Due to its toxic effects in the marine environment, mercury is particularly dangerous. Microbiological processes convert toxic inorganic mercury into much more toxic forms of mercury. Its compounds accumulated in fish or shellfish pose a direct threat to human life and health. Mercury, cadmium, lead, copper, zinc, chromium, arsenic and other heavy metals not only accumulate in marine organisms, thereby poisoning marine food, but also have a detrimental effect on sea inhabitants. The accumulation coefficients of toxic metals, i.e. their concentration per unit weight in marine organisms relative to seawater, vary widely - from hundreds to hundreds of thousands, depending on the nature of the metals and the types of organisms. These coefficients show how harmful substances accumulate in fish, shellfish, crustaceans, planktonic and other organisms.
In some countries, under public pressure, laws have been passed prohibiting the discharge of untreated wastewater into inland waters - rivers, lakes, etc.
In order not to incur “extra expenses” for the installation of necessary structures, the monopolies found a convenient way out. They build diversion channels that carry wastewater directly to the sea, not sparing the resorts.
Dumping of waste into the sea for the purpose of burial (dumping).
A terrible threat to all life, not only in the ocean, but also on land, is posed by atomic tests at sea and the burial of radioactive waste in the depths of the sea.
Many countries with access to the sea carry out marine disposal of various materials and substances, in particular dredging soil, drilling slag, industrial waste, construction waste, solid waste, explosives and chemicals, and radioactive waste. The volume of burials amounted to about 10% of the total mass of pollutants entering the World Ocean.
The basis for dumping at sea is the ability of the marine environment to process large quantities of organic and inorganic substances without much damage to the water. However, this ability is not unlimited. Therefore, dumping is seen as a forced measure, a temporary tribute from society to the imperfection of technology. Industrial slag contains a variety of organic substances and heavy metal compounds. Household waste on average contains (by dry matter weight) 32-40% organic matter; 0.56% nitrogen; 0.44% phosphorus; 0.155% zinc; 0.085% lead; 0.001% mercury; 0.001% cadmium.
During discharge, when the material passes through a column of water, part of the pollutants goes into solution, changing the quality of the water, while the other 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, dissolution of suspended matter, accumulation of metals in dissolved form, and the appearance of hydrogen sulfide.
The presence of a large amount of organic substances creates a stable reducing environment in the soil, in which a special type of silt water appears, containing hydrogen sulfide, ammonia, and metal ions. Benthic organisms and others are affected to varying degrees by the impact of discharged materials.
The discharge of dumping materials to the bottom and prolonged increased turbidity of the water lead to the death of sedentary benthos from suffocation. In surviving fish, mollusks and crustaceans, their growth rate is reduced due to deteriorating feeding and breathing conditions. The species composition of a given community often changes.
When organizing a control system for waste discharges into the sea, identifying dumping areas and determining the dynamics of pollution of sea water and bottom sediments is of decisive importance. To identify possible volumes of discharge into the sea, it is necessary to carry out calculations of all pollutants in the material discharge.
The dumping of waste led to massive deaths of ocean inhabitants. The main sources of pollution of water bodies are enterprises of ferrous and non-ferrous metallurgy, chemical and petrochemical, pulp and paper, and light industry. Wastewater is contaminated with minerals, salts of heavy metals (copper, lead, zinc, nickel, mercury, etc.), arsenic, chlorides, etc. Woodworking and pulp and paper industries. The main source of wastewater generation in the industry is cellulose production, based on sulfate and sulfite methods of wood pulping and bleaching. As a result of the activities of the oil refining industry, significant quantities of petroleum products, sulfates, chlorides, nitrogen compounds, phenols, salts of heavy metals, etc. entered water bodies. Suspended substances, total nitrogen, ammonium nitrogen, nitrates, chlorides, sulfates, etc. also entered natural water bodies. total phosphorus, cyanides, cadmium, cobalt, copper, manganese, nickel, mercury, lead, chromium, zinc, hydrogen sulfide, carbon disulfide, alcohols, benzene, formaldehyde, phenols, surfactants, urea, pesticides, semi-finished products.
Light industry. The main pollution of water bodies comes from textile production and leather tanning processes.
Textile industry wastewater contains: suspended solids, sulfates, chlorides, phosphorus and nitrogen compounds, nitrates, synthetic surfactants, iron, copper, zinc, nickel, chromium, lead, fluorine. Tanning industry - nitrogen compounds, phenols, synthetic surfactants, fats and oils, chromium, aluminum, hydrogen sulfide, methanol, fenaldehyde. Domestic wastewater is water from kitchens, toilets, showers, baths, laundries, canteens, hospitals, domestic premises of industrial enterprises, etc.
Another serious problem threatens the World Ocean and humanity as a whole. The current climate model takes into account the interaction of the Earth's heat, clouds and ocean currents. This, of course, does not simplify the preparation of climate and environmental forecasts, since the range of potential climate threats is becoming wider.
Timely receipt of information about water evaporation, cloud formation and the nature of ocean currents makes it possible, using data on the heating of the Earth, to make long-term forecasts of their changes.
Vortex storms - cyclones - pose an increasing threat. But the giant “pumping” system of the World Ocean also threatens to stop working - a system that depends on low polar temperatures and, like a powerful pump, “pumps” cold deep waters towards the equator. This means, for example, that in the absence of a cold current, the warm Gulf Stream will gradually stop flowing north. Therefore, the paradoxical idea that as a result of a strong greenhouse effect with a changed nature of currents, an ice age will begin again in Europe, is being seriously discussed.
At first the ocean will react weakly. However, in some places there will be disruptions to normal processes as a consequence of the increasing warming of the Earth. These disturbances include frequent typhoons and the El Niño phenomenon - when the deep cold Humboldt Current coming from the south and coming to the surface off the coast of South America is periodically pushed away from the coast by the influx of warm tropical waters. As a result, there is a massive death of marine animals; In addition, moist air masses, when reaching land, cause destructive rainfall and lead to large economic losses. If we leave everything as before and continue to “press” with incredible force on the nature around us, we will soon cease to recognize it.
The main reason for the modern degradation of the Earth's natural waters is anthropogenic pollution. Its main sources are:
a) wastewater from industrial enterprises;
b) municipal wastewater of cities and other populated areas;
c) runoff from irrigation systems, surface runoff from fields and other agricultural facilities;
d) atmospheric fallout of pollutants onto the surface of water bodies and drainage basins.
In addition, unorganized runoff of precipitation water ("storm runoff", melt water) pollutes water bodies with a significant portion of man-made terrapollutants.
Anthropogenic pollution of the hydrosphere has now become global in nature and has significantly reduced the available exploitable fresh water resources on the planet.
Thermal pollution of the surface of reservoirs and coastal marine areas occurs as a result of the discharge of heated wastewater by power plants and some industrial production.
The discharge of heated water in many cases causes an increase in water temperature in reservoirs by 6-8 degrees Celsius. The area of heated water spots in coastal areas can reach 30 square meters. km. More stable temperature stratification prevents water exchange between the surface and bottom layers. The solubility of oxygen decreases, and its consumption increases, since with increasing temperature the activity of aerobic bacteria decomposing organic matter increases. The species diversity of phytoplankton and the entire algal flora is increasing.
Radioactive contamination and toxic substances.
The danger that directly threatens human health is also associated with the ability of some toxic substances to remain active for a long time. A number of them, such as DDT, mercury, not to mention radioactive substances, can accumulate in marine organisms and be transmitted over long distances along the food chain.
Plants and animals are susceptible to contamination by radioactive substances. In their bodies there is a biological concentration of these substances, transmitted to each other through food chains. Infected small organisms are eaten by larger ones, resulting in dangerous concentrations in the latter. The radioactivity of some planktonic organisms can be 1000 times higher than the radioactivity of water, and some fish, which represent one of the highest links in the food chain, even 50 thousand times. The Moscow Treaty banning the testing of nuclear weapons in the atmosphere, outer space and under water stopped the progressive radioactive mass pollution of the World Ocean. However, the sources of this pollution remain in the form of plants for purifying uranium ore and processing nuclear fuel, nuclear power plants, and reactors.
The accumulation of nuclear weapons in the World Ocean occurred in different ways. Here are the main ones:
1. Deployment of nuclear weapons in the World Ocean as deterrents located on nuclear submarines;
2.Nuclear reactors used on ships with nuclear power plants, mainly submarines, some of which sank with nuclear fuel and nuclear equipment on board;
3. Use of the World Ocean for transportation of nuclear waste and spent nuclear fuel;
4. Using the World Ocean as a dump for nuclear waste;
5. Testing of nuclear weapons in the atmosphere, especially over the Pacific Ocean, which became a source of nuclear contamination of both water areas and land;
6. Underground nuclear weapons testing, like those recently conducted by France in the South Pacific, endangering the fragile Pacific atolls and leading to true nuclear contamination of the oceans and the risk of more pollution if the atolls crack due to testing or future tectonic activity.
The problems arising from the proliferation of nuclear weapons in the World Ocean can be viewed from several perspectives.
From an environmental perspective, there are problems of nuclear pollution in the world's oceans affecting the food chain. The biological resources of the seas and oceans ultimately affect the humanity that depends on them.
Now the threat of nuclear contamination of the aquatic environment has somewhat decreased, since nuclear tests have not been carried out at sea since 1980. Moreover, the nuclear powers have committed themselves to accede to the Comprehensive Nuclear Test Ban Treaty, which they promised to conclude by 1996. The signing of the Treaty will All underground nuclear tests have been stopped.
Discharge of high-level radioactive waste into the world's oceans has been reduced since the 1975 Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Materials, but dumping of low-level radioactive waste authorized by the International Atomic Energy Agency and non-compliance by individual countries are cause for concern. Problems can be foreseen in the future as radioactive contaminants stored in canisters or contained in fuel or weapons aboard sunken nuclear submarines are released into sea waters.
Increased use of the world's oceans to transport nuclear waste and spent nuclear fuel (for example, between Japan and France) has significantly increased the risk of pollution. Coastal and island states located along the transport routes of nuclear materials are at high risk of contamination in the event of a maritime disaster. The role of International Law regarding waterborne transport of hazardous materials must be strengthened and its provisions must be strictly enforced by the international community in order to prevent catastrophic situations.
Mineral, organic, bacterial and biological pollution of the World Ocean . Mineral contamination is usually represented by sand, clay particles, particles of ore, slag, mineral salts, solutions of acids, alkalis, etc. Bacterial and biological contamination is associated with various pathogenic organisms, fungi and algae.
Organic pollution is divided by origin into plant and animal. Pollution is caused by the remains of plants, fruits, vegetables and cereals, vegetable oil, etc. Pollution of animal origin is wool processing, fur production, microbiological industry enterprises, etc.).
The removal of organic matter into the ocean is estimated at 300 - 380 million tons/year. Wastewater containing suspensions of organic origin or dissolved organic matter has a detrimental effect on the condition of water bodies. As they settle, the suspensions flood the bottom and delay the development or completely stop the vital activity of these microorganisms involved in the process of self-purification of water. When these sediments rot, harmful compounds and toxic substances, such as hydrogen sulfide, can be formed, which lead to the contamination of all water in the river.
A significant volume of organic substances, most of which are not characteristic of natural waters, is discharged into rivers along with industrial and domestic wastewater.
With such an area and volume of the World Ocean, it is simply impossible to believe that it can be polluted, much less endangered. Nevertheless, it is so. All natural pollution of the ocean: the runoff of rock destruction products, the removal of organic substances by rivers, the entry of volcanic ash into the water, etc. - are perfectly balanced by nature itself.
Marine organisms are adapted to such pollution, and, moreover, they cannot live without it. In the complex ecological system of the World Ocean, all substances that enter the water naturally and in appropriate quantities and concentrations are successfully processed without any harm to the inhabitants of the sea, which continues to remain clean all the time.
As a result of the growth of cities and the accumulation of a large number of people in one place, household waste enters the ocean in a concentrated manner and does not have time to be disposed of during the self-purification process. In addition, industry discharges production by-products into the sea (directly through rivers or through the atmosphere) - substances that are generally not decomposed by marine organisms. In most cases, they have a harmful effect on sea inhabitants. Many artificial materials have appeared in everyday life (plastics, polyethylene, synthetic fabrics, etc.), products from which, having served their useful life, also end up in the ocean, polluting its bottom.
Many people, due to their lack of culture and ignorance, view the ocean as a giant cesspool, throwing overboard everything that they consider unnecessary. Often, sea pollution increases as a result of accidents and accidents with ships or at work, when large amounts of oil or other substances immediately enter the water, the discharge of which was not intended.
Port construction , industrial enterprises and even health institutions and hotels on the seashore take away from the ocean the most biologically productive zone - the littoral zone (a section of the coast that is flooded with sea water during high tide and drained during low tide.). Combined with excessive fishing, this also leads to impoverishment of life.
Hello dear readers! Today I would like to talk to you about ocean pollution.
The ocean (more about what the ocean is) occupies about 360 million km 2 of the surface of the globe. Unfortunately, people use it as a waste dumping site, which causes great harm to the local flora and fauna.
Land and ocean are connected by rivers (more about rivers), flowing into the seas (more about what a sea is) and carrying various pollutants. Chemicals that do not disintegrate upon contact with soil (you can read more about soil), such as petroleum products, oil, fertilizers (especially nitrates and phosphates), insecticides and herbicides, end up in rivers and then into the ocean as a result of leaching.
The ocean ends up being the dumping ground for this cocktail of poisons and nutrients. The main pollutants of the oceans are petroleum products and oil. And air pollution, household garbage and sewage significantly exacerbate the harm they cause.
Oil and plastics washed up on beaches remain along the high tide mark. This indicates pollution of the seas, as well as the fact that many wastes are not decomposed by microorganisms.
Studies of the North Sea have shown that about 65% of the pollutants found there were transported by rivers.
Another 7% of pollutants came from direct discharges (mostly wastewater), 25% from the atmosphere (including 7,000 tons of lead from vehicle exhaust), and the rest from ship discharges and discharges.
Ten US states burn waste at sea (read more about this country). In 1980, 160,000 tons were destroyed in this way, but this figure has since decreased.
Ecological disasters.
All serious cases of ocean pollution are associated with oil. Every year, between 8 and 20 million barrels of oil are deliberately dumped into the ocean. This occurs as a result of the practice of washing tankers and holds, which is widespread.
Such violations previously often went unpunished. Today, with the help of satellites, it is possible to collect all the necessary evidence, as well as bring the perpetrators to justice.
The Exxon Valdez tanker ran aground in 1989 near Alaska. Almost 11 million gallons of oil (about 50,000 tons) were spilled into the ocean, and the resulting stain stretched along the coast for 1,600 km.
The owner of the vessel, the oil company Exxon Mobil, was ordered by the court to pay a fine to the state of Alaska, only in the case of criminal liability, 150 million dollars, this is the largest environmental fine in history.
The court forgave the company $125 million from this amount in recognition of its participation in eliminating the consequences of the disaster. But Exxon paid another $100 million for environmental damage and, over the course of 10 years, $900 million in civil claims.
The last payment to Alaska and federal authorities was made in September 2001, but the government still has until 2006 to file a claim for up to $100 million if environmental consequences are discovered that could not have been foreseen at the time of the trial.
Claims from individuals and companies also amount to a huge amount, and many of these claims are still being litigated.
The Exxon Valdez is one of the most famous, yet many, oil spills at sea.
The place of small and large environmental disasters associated with the transportation of extremely dangerous goods remains, of course, the ocean.
This was the case with the Akatsuri Maru ships, which in 1992 transported from Europe (more about this part of the world) to Japan a large batch of radioactive plutonium for processing, as well as the Karen Bee, on board which in 1987, there were 2000 tons of toxic waste.
Wastewater.
Sewage, besides oil, is one of the most harmful wastes. In small quantities they promote the growth of fish and plants and enrich water, but in large quantities they destroy ecosystems.
Marseille (France) and Los Angeles (USA) are two of the world's largest wastewater discharge sites. For more than two decades, specialists there have been cleaning contaminated waters.
The spreading of wastewater discharged by exhaust manifolds is clearly visible on satellite images. Underwater surveys show the resulting death of marine organisms (underwater deserts strewn with organic debris), but restoration measures taken in recent years have significantly improved the situation.
To reduce the danger of sewage, efforts are made to liquefy it, while bacteria (read more about bacteria) are killed by sunlight.
In California, such measures have proven effective. There, household waste is discharged into the ocean - the result of the life activity of almost 20 million inhabitants.
Metals and chemicals.
The content of metals, PCBs (polychlorinated biphenyls), DDT (a long-lasting toxic pesticide based on an organochlorine compound in nature) in waters has decreased in recent years, but the amount of arsenic has inexplicably increased.
DDT has been banned in England since 1984, but it is still used in some African areas.
Heavy metals such as nickel, cadmium, lead, chromium, copper, zinc and arsenic are hazardous chemicals that can disrupt the ecological balance.
It is estimated that up to 50,000 tonnes of these metals are dumped into the North Sea alone each year. The pesticides endrin, dieldrin and aldrin, which accumulate in animal tissue, are of even greater concern.
The long-term effects of using such chemicals are still unknown. TBT (tributyltin) is also harmful to marine life. It is used to paint the keels of ships, which prevents them from becoming overgrown with algae and shells.
It has already been proven that TBT changes the sex of male whelks (a type of crustacean), and as a result of this, the entire population is female, and this, of course, excludes the possibility of reproduction.
There are substitutes that do not have a harmful effect on wildlife. For example, it could be a copper-based compound that is 1000 times less toxic to plants and animals.
Impact on ecosystems.
All oceans suffer from pollution. But water pollution in the open sea is less than in coastal waters, since there are more sources of pollutants in this area: from heavy traffic of sea vessels to coastal industrial installations.
Off the eastern coast of North America and around Europe, shallow continental shelves are home to nurseries for fish, mussels and oysters that are vulnerable to pollutants, algae (more about algae) and toxic bacteria.
In addition, oil exploration work is also being carried out on the shelves, and this naturally increases the risk of oil spills and pollution.
The Mediterranean Sea (partially internal) is connected to the Atlantic Ocean, and once every 70 years it is completely renewed by it.
Up to 90% of the wastewater here came from 120 coastal cities, and other pollutants accounted for the 360 million people holidaying or living in 20 Mediterranean countries.
The Mediterranean Sea has become a huge polluted ecosystem, which receives about 430 billion tons of waste every year.
The sea coasts of Italy, France and Spain are the most polluted. This can be explained by the work of heavy industry and the influx of tourists.
Of the native mammals, Mediterranean monk seals fared the worst. Due to the increased tourist flow, they have become rare.
And the islands, their remote habitats, can now be quickly reached by boat, making these places even more accessible to scuba divers. In addition, a large number of seals die after becoming entangled in fishing nets.
Green sea turtles live in all oceans where the water temperature does not drop below 20°C. But the nesting grounds of these animals, both in the Mediterranean Sea (in Greece) and in the ocean, are under threat.
Eggs are taken from captured turtles on the island of Bali (Indonesia). This is done in order to give young turtles the opportunity to grow up, and then release them into the wild when they have a better chance of surviving in polluted waters.
Flowering water.
Blooms, which occur due to massive algae or plankton growth, are another common form of ocean pollution.
The growth of algae Chlorochromulina holylepis has caused a bloom in the waters of the North Sea off the coast of Denmark and Norway. As a result of all this, the salmon fishery has been seriously affected.
Such phenomena have been known for some time in temperate waters, but in the tropics and subtropics, red tide was first noticed in 1971 near Hong Kong. Such cases were subsequently often repeated.
It is believed that this phenomenon is associated with industrial emissions of large amounts of metal trace elements, which act as biostimulants for plankton growth.
Oysters, like other bivalves, play an important role in filtering water. Previously, in the Maryland portion of the Chesapeake Bay, oysters filtered the water within 8 days. Today, due to pollution and algal blooms, they spend 480 days on this.
Algae, after blooming, die and decompose, which contributes to the proliferation of bacteria that absorb vital oxygen.
All marine animals that obtain food by filtering water are very sensitive to pollutants that accumulate in their tissues.
Pollution is poorly tolerated by corals, which consist of giant colonies of single-celled organisms. Today, these living communities - coral reefs and atolls - are under serious threat.
Danger to humans.
Harmful organisms contained in wastewater breed in shellfish and cause numerous diseases in humans. Escherichia coli is the most common bacterium and is also an indicator of infection.
PCBs accumulate in marine organisms. These industrial pollutants are poisonous to humans and animals.
They are persistent chlorine compounds, like other ocean pollutants such as HCH (hexachlorocyclohexane), used in wood preservatives and pesticides. These chemicals leach from the soil and end up in the sea. There they penetrate the tissues of living organisms and thus pass through the food chain.
Humans can eat fish with HCH or PCBs, other fish can eat them, and then they can be eaten by seals, which in turn become food for polar bears or some species of whales.
The concentration of chemicals increases each time they move from one animal level to another.
The polar bear, who suspects nothing, eats the seals, and along with them absorbs the toxins that were contained in tens of thousands of infected fish.
It is believed that pollutants are also responsible for increasing the susceptibility of marine mammals to distemper, which struck in 1987-1988. North Sea. At least 11 thousand long-snouted and common seals died then.
Metal pollutants in the ocean are also likely to cause skin ulcers and enlarged livers in fish, including flounder, of which 20% of the North Sea population is affected by these diseases.
Toxic substances entering the ocean may not be harmful to all organisms. In such conditions some lower forms can flourish.
Polychaete worms (polychaetes) live in relatively polluted waters and often serve as environmental indicators of relative pollution.
The use of marine nematodes continues to be studied to monitor the health of the oceans.
Legislation.
There have been attempts to make the ocean cleaner through legislation, but this situation is difficult to control. In 1983, 27 countries signed the Cartagena Convention for the Protection and Development of the Marine Environment of the Caribbean Region.
Other attempts have been made to control ocean dumping, including the UN Convention on the Continental Shelf (1958), the UN Convention on the Law of the Sea (1982), and the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Materials (1972).
Marine reserves are a good, but not optimal, way to protect the habitats and wildlife of coastal waters.
They were created in New Zealand back in the 1960s, as well as off the coast of North America and Europe.
The International Union for Conservation of Nature and Natural Resources (IUCN) has declared Taka Bone Rote Atoll (Indonesia) a “disaster area”. It covers an area of 2220 km2 and includes regular and barrier coral reefs.
In general, the flora and fauna of the ocean are still struggling to survive in the face of ongoing human pollution.
So we looked at ocean pollution😉See you in new posts under the heading global problems of humanity! And if you don’t want to miss the latest articles, subscribe to blog updates by email 🙂
Ministry of Education and Science of the Russian Federation
State budgetary educational institution of higher professional education
"South Ural State University"
Faculty of Physics and Metallurgy
Department of Physical Chemistry
Discipline: "Ecology"
Topic: “7.Pollution of the world’s oceans”
Teacher: Ph.D., Associate Professor Antonenko V.I.
Chelyabinsk 2015
INTRODUCTION
WORLD OCEAN
HUMAN ACTIVITIES AFFECTING THE STATE OF THE HYDROSPHERE
MAIN TYPES OF POLLUTION
ECOLOGICAL CONSEQUENCES OF HYDROSPHERE POLLUTION
MEASURES FOR PURIFICATION AND PROTECTION OF WATER
CONCLUSION
BIBLIOGRAPHY
The role of the World Ocean in the functioning of the biosphere as a single system cannot be overestimated. The water surface of oceans and seas covers most of the planet. When interacting with the atmosphere, ocean currents largely determine the formation of climate and weather on Earth. All oceans, including enclosed and semi-enclosed seas, are of enduring importance in the global food supply of the world's population.
The ocean, especially its coastal zone, plays a leading role in supporting life on Earth, since about 70% of the oxygen entering the planet’s atmosphere is produced during the process of plankton photosynthesis.
The world's oceans cover 2/3 of the earth's surface and provide 1/6 of all animal proteins consumed by the population as food.
The ocean and seas are experiencing increasing environmental stress due to pollution, overfishing of fish and shellfish, destruction of historical fish spawning grounds, and deterioration of coastlines and coral reefs.
Currently, the leading countries of the world are taking measures to protect the nature of the World Ocean. These are the International Whaling Convention of 1946, the establishment of 200-mile economic zones by the decision of the Third UN Convention on the Law of the Sea, national legislation regulating marine fishing and providing for the protection of marine biological resources. However, at present, neither the problem of depletion of ocean biological resources nor the problem of seawater pollution has been solved.
1.WORLD OCEAN The main feature of the World Ocean is its huge, overwhelming size. It is a well-known hackneyed, but nevertheless true, remark that our planet should be called not Earth, but Ocean. The world's oceans occupy 71% of the planet's surface. The most important global consequence of this relationship between land and sea is its influence on the water and heat balance of the Earth. Evaporation from the ocean surface is both a major source of water in the global hydrological cycle and an important component of the global heat balance. The world's oceans are also a huge accumulator of substances, containing them in dissolved quantities (the average concentration of dissolved substances in sea water, or its salinity, is 35 g/l). The World Ocean also takes part in the cycle of minerals on Earth. With river flow, silt and sand - products of water erosion of continental rocks - enter the ocean. This material is deposited in the ocean as bottom sediments, forming sedimentary rocks with the participation of living organisms. According to most modern scientists, life on Earth appeared in the ocean. Proof of this is that the mineral composition of the internal environment of organisms (blood, lymph) is almost identical to the mineral composition of sea water. The World Ocean contains all types of animals, many of which live only in sea water, all groups of lower and individual types of higher plants, many protozoa and fungi. The microflora of the World Ocean has not yet been fully studied, but it is also very numerous. This circumstance plays a significant role in the stabilization of biogeochemical cycles and the ecosphere as a whole. The world's oceans are actively used by humans in the following ways: The ocean is an environment for maritime transport; The ocean is a source of food resources; The ocean is a source of mineral resources; The ocean is a source of recreational resources; The ocean is a geopolitical factor. From ancient times to the present day, the economic potential of a country and its political position are largely determined by the country’s access to the sea. The capitals of many landlocked developing countries are their main trading ports (Dhaka is the capital of Bangladesh, Montevideo is the capital of Paraguay). The special position of Great Britain in Europe, due to which it was significantly less affected by European armed conflicts than Germany and France, is due to the fact that it is completely surrounded by sea; The ocean is a dumping ground for hazardous waste. It is with the nature of human use of the World Ocean that its main environmental problems are associated. 2.HUMAN ACTIVITIES AFFECTING THE STATE OF THE HYDROSPHERE At the beginning of the 20th century, due mainly to the expansion of agriculture, the anthropogenic share of sediment flow from land to sea was greater than natural. Currently, river dams and irrigation systems, built mainly in the second half of this century, intercept and significantly reduce the flow of sediment and nutrients adsorbed on it, especially phosphorus compounds. The river flow increasing into the sea also costs water for evaporation in general, somewhat lower, mainly due to the developing irrigation. A decrease in river flow leads to an increase in the salinity of sea waters in closed seas and bays. Use of land in the coastal strip. The closer to the interface between ocean water and land, the higher the density of land use and, accordingly, the higher the degradation of coastal lands. In this zone, competition in the use of land between residential areas, ports and industrial buildings is also the most intense. The main area of pollution is ports, where polluted water enters from ships, drains from urban areas, and enters along with sediment from rivers. Ports require constant dredging to move large quantities of sediment. Clean sediment, although it necessitates dredging, does not cause much harm. However, about 10% of dredging material is contaminated with heavy metals, petroleum products, biogenic and organochlorine compounds. The channel of the Neva delta, Ekaterinivka, contains about 40 kg of lead per ton of sand and silt accumulated at the bottom. On the seabed of one of the main branches of the Rhine delta, passing through the world's largest port of Rotterdam (Netherlands), an artificial island of contaminated sediment has been created. The island is uninhabitable, but can be used for industrial purposes, such as warehouses. Contaminated pumps can be controlled to a certain extent: dumped on the edge of the shelf, so that they then move due to gravitational forces into a deeper zone of the continental slope; cover contaminated material with clean material; concentrate sediment in special restricted areas. A special problem is the discharge of industrial waste and sludge from wastewater treatment plants. These substances can be extremely toxic. Such discharges without treatment can only be called barbaric. A particular problem is the spread of plastic waste on the surface of waters. Even in the open ocean there is a lot of it. These are abandoned and lost nets, floats, packaging of goods, bottles, etc. Such garbage practically does not decompose and remains on the surface of the water or on beaches for a very long time. Some marine animals and birds ingest plastic debris, which leads to adverse effects and even death. Transport of hazardous substances is an important factor in water pollution. This especially applies to the transportation of oil and petroleum products. Shipping provides approximately half of the anthropogenic input of oil into the world's oceans. Maps of ocean oil pollution and major shipping lines largely coincide. Oil and petroleum products are the most common pollutants in the World Ocean. Petroleum oils pose the greatest threat to the cleanliness of water bodies. These highly persistent pollutants can travel over 300 km from their source. Light oil fractions, floating on the surface, form a film that insulates and impedes gas exchange. In this case, one drop of petroleum oil forms, spreading over the surface, a spot with a diameter of 30-150 cm, and 1 ton - about 12 km of oil film. ocean hydrosphere garbage security Fig. 1 - Oil pollution in the World Ocean The thickness of the film is measured from fractions of a micron to 2 cm. The oil film has high mobility and is resistant to oxidation. The oil film stops the flow of oxygen into the water, disrupts moisture and gas exchange, and destroys plankton and fish. And this is only a small part of the harm that oil brings to sea water and its inhabitants. 3.MAIN TYPES OF POLLUTION The most common types of water pollution are chemical and bacterial. Much less often - radioactive, mechanical and thermal. Chemical pollution is the most common, persistent and far-reaching. It can be organic (phenols, naphthenic acids, pesticides, etc.) and inorganic (salts, acids, alkalis), toxic (arsenic, mercury compounds, lead, cadmium, etc.) and non-toxic. When deposited to the bottom of reservoirs or during filtration in a formation, harmful chemicals are sorbed by rock particles, oxidized and reduced, precipitated, etc., however, as a rule, complete self-purification of contaminated waters does not occur. The source of chemical contamination of groundwater in highly permeable soils can extend up to 10 km or more. Bacterial pollution is expressed in the appearance of pathogenic bacteria, viruses, protozoa, fungi, etc. in water. This type of pollution is temporary. It is very dangerous to contain radioactive substances in water, even at very low concentrations, causing radioactive contamination. The most harmful are “long-lived” radioactive elements that have an increased ability to move in water (strontium-90, uranium, radium-226, cesium, etc.). Mechanical pollution is characterized by the ingress of various mechanical impurities into the water (sand, slag, silt, etc.) Thermal pollution is associated with an increase in water temperature as a result of its mixing with warmer surface or process waters. As the temperature rises, the gas and chemical composition in the waters changes, which leads to the proliferation of anaerobic bacteria, the growth of aquatic organisms and the release of toxic gases - hydrogen sulfide and methane. At the same time, water “blooming” occurs, as well as the accelerated development of microflora and microfauna, which contributes to the development of other types of pollution. 4.ECOLOGICAL CONSEQUENCES OF HYDROSPHERE POLLUTION The rate at which pollutants enter the world's oceans has increased sharply in recent years. Environmental consequences are expressed in the following processes and phenomena: 5.MEASURES FOR PURIFICATION AND PROTECTION OF WATER The most serious problem of the seas and oceans in our century is oil pollution, the consequences of which are disastrous for all life on Earth. Therefore, in 1954, an international conference was held in London with the goal of developing concerted actions to protect the marine environment from oil pollution. It adopted a convention defining the responsibilities of states in this area. Later, in 1958, four more documents were adopted in Geneva: on the high seas, on the territorial sea and the contiguous zone, on the continental shelf, on fisheries and the protection of living marine resources. These conventions legally established the principles and norms of the law of the sea. They obliged each country to develop and implement laws prohibiting pollution of the marine environment with oil, radioactive waste and other harmful substances. A conference held in London in 1973 adopted documents on the prevention of pollution from ships. According to the adopted convention, each ship must have a certificate - evidence that the hull, mechanisms and other equipment are in good condition and do not cause damage to the sea. Compliance with certificates is checked by inspection upon entry into the port. It is prohibited to discharge oil-containing water from tankers; all discharges from them must be pumped only to onshore receiving points. Electrochemical installations have been created for the purification and disinfection of ship wastewater, including domestic wastewater. The Institute of Oceanology of the Russian Academy of Sciences has developed an emulsion method for cleaning sea tankers, which completely eliminates the entry of oil into the water area. It consists of adding several surfactants (ML preparation) to the wash water, which allows cleaning on the ship itself without discharging contaminated water or oil residues, which can subsequently be regenerated for further use. Up to 300 tons of oil can be washed from each tanker. In order to prevent oil leaks, the designs of oil tankers are being improved. Many modern tankers have a double bottom. If one of them is damaged, oil will not spill out; it will be retained by the second shell. Ship captains are required to record in special logs information about all cargo operations with oil and petroleum products, and note the place and time of delivery or discharge of contaminated wastewater from the ship. Floating oil skimmers and side barriers are used to systematically clean up water areas from accidental spills. Also, in order to prevent oil spreading, physicochemical methods are used. A foam group preparation has been created that, when in contact with an oil slick, completely envelops it. After spinning, the foam can be used again as a sorbent. Such drugs are very convenient due to their ease of use and low cost, but their mass production has not yet been established. There are also sorbent agents based on plant, mineral and synthetic substances. Some of them can collect up to 90% of spilled oil. The main requirement that is placed on them is unsinkability. After oil is collected by sorbents or mechanical means, a thin film always remains on the surface of the water, which can be removed by spraying chemicals that decompose it. But at the same time, these substances must be biologically safe. A unique technology has been created and tested in Japan, with the help of which a giant stain can be eliminated in a short time. Kansai Sage Corporation has released the ASWW reagent, the main component of which is specially processed rice husk. Sprayed over the surface, the drug absorbs the emission within half an hour and turns into a thick mass that can be pulled off with a simple net. The original cleaning method was demonstrated by American scientists in the Atlantic Ocean. A ceramic plate is lowered under the oil film to a certain depth. An acoustic record is connected to it. Under the influence of vibration, it first accumulates in a thick layer above the place where the plate is installed, and then mixes with water and begins to gush. An electric current applied to the plate ignites the fountain, and the oil burns completely. To remove oil stains from the surface of coastal waters, American scientists have created a modification of polypropylene that attracts fatty particles. On a catamaran boat, a kind of curtain made of this material was placed between the hulls, the ends of which hang into the water. As soon as the boat hits the slick, the oil firmly adheres to the “curtain”. All that remains is to pass the polymer through the rollers of a special device, which squeezes the oil into the prepared container. Since 1993, the dumping of liquid radioactive waste (LRW) has been prohibited, but their number is steadily growing. Therefore, in order to protect the environment, liquid radioactive waste cleanup projects began to be developed in the 90s. In 1996, representatives of Japanese, American and Russian firms signed a contract to create a facility for processing liquid radioactive waste accumulated in the Russian Far East. The Japanese government allocated $25.2 million for the project. However, despite some successes in the search for effective means of eliminating pollution, it is too early to talk about solving the problem. Only by introducing new methods of cleaning water areas it is impossible to ensure the cleanliness of the seas and oceans. The central task that all countries need to solve together is the prevention of pollution. CONCLUSION Currently, the use of the World Ocean by humans and human economic activities have caused local and global environmental problems and disruptions in the functioning of marine ecosystems. As a result of human activity, certain species of fauna have disappeared; some other species are on the verge of destruction. Some areas of the seas have been subjected to severe pollution, which has radically disrupted the functioning of local ecosystems. Pesticides are found where they were not used, and in organisms against which these pesticides were not used: in the organisms of polar animals, whales, and fish. Development of coastal areas leads to the destruction of part of the coastal ecosystems that are inextricably linked with the ocean. Ocean fish resources have recently been depleted. The threats posed by the ecological crisis of the World Ocean are now clear to all of humanity: a decrease in fish catch, the loss of unique recreational areas for people, a general poisoning of the biosphere and then of people. And real legal measures have already begun to be taken (approval of international environmental conventions and agreements, national legislative acts and control over their implementation), measures for the artificial renewal of biological resources of the seas (mariculture), marine reserves have been created (the Florida Nature Reserve in the USA is specialized in the protection of manatees) . Despite poaching, the restoration of the population of baleen whales in the World Ocean has begun. Artificial artificial islands are being created for development. And yet, global environmental problems of the ocean are still far from being resolved. One of the most important tasks of modern oceanology - the study of processes occurring in the ocean and the prevention of an environmental crisis - has begun to be realized. BIBLIOGRAPHY 1. Ecology: textbook. / L. V. Peredelsky, V. I. Korobkin, O. E. Prikhodchenko. - M.: Prospekt, 2009.- 512 p. .
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 assimilative capacity
4. Conclusions from the assessment of the assimilation capacity of the marine ecosystem for pollutants using 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 distribution 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 rational use of natural resources.
Marine pollution is defined as: “the introduction by humans, directly or indirectly, of substances or energy into the marine environment (including estuaries), causing harmful consequences 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 beneficial properties." This list includes substances with toxic properties, heated water discharges (thermal pollution), microbial pathogens, solid waste, suspended solids, nutrients, and several other forms of anthropogenic impacts.
The most pressing problem in our time has become the problem of chemical pollution of the ocean.
Sources of ocean and sea pollution include the following:
Discharge of industrial and household waters directly into the sea or with river flow;
Receipt from land of various substances used in agriculture and forestry;
Deliberate disposal of pollutants at sea; leakage of various substances during ship operations;
Accidental releases from ships or subsea pipelines;
Seabed mining;
Transport of pollutants through the atmosphere.
The list of pollutants produced by the ocean is extremely extensive. They all differ in the degree of toxicity and scale of distribution - from coastal (local) to global.
More and more new pollutants are being found in the World Ocean. The most dangerous organochlorine compounds, polyaromatic hydrocarbons and some others are becoming widespread globally. They have a high bioaccumulative ability, a sharp toxic and carcinogenic effect.
The steady increase in the total impact of many sources of pollution leads to progressive eutrophication of coastal marine zones and microbiological pollution of water, which significantly complicates the use of water for various human needs.
Oil and petroleum products. Petroleum is a viscous oily liquid, usually dark brown in color and weakly fluorescent. Oil consists predominantly of saturated aliphatic and hydroaromatic hydrocarbons (from C 5 to C 70) and contain 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) are saturated cyclic compounds C n H 2 n with 5-6 carbon atoms in the ring (30-60% of the total composition of oil). In addition to cyclopentane and cyclohexane, bicyclic and polycyclic naphthenes are found in oil. These compounds are very stable and poorly biodegradable.
3. Aromatic hydrocarbons (20-40% of the total composition of oil) - unsaturated cyclic compounds of the benzene series, containing 6 less carbon atoms in the ring 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. Olefips (alkenes) (up to 10% of the total composition of oil) - unsaturated non-cyclic compounds with one or two hydrogen atoms at each carbon atom in a molecule having a straight or branched chain.
Depending on the field, oils vary significantly in their composition. Thus, Pennsylvania and Kuwait oils are classified as paraffinic, Baku and California are predominantly naphthenic, and the remaining oils are of 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 pose 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 are associated with the metabolic activity of organisms and the breakdown of their residues. However, in areas of intense pollution, the level 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. Petroleum 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 series of alkanes C 12 -C 22 the ratio of even and odd members is equal to unity, while biogenic hydrocarbons in the same series contain predominantly odd members.
3. Petroleum contains a wider range of cycloalkanes and aromatic hydrocarbons. Many compounds, such as mono-, di-, tri- and tetramethylbenzenes, are not found in marine organisms.
4. Oil contains numerous naphthenic-aromatic hydrocarbons, various heterocompounds (containing sulfur, nitrogen, oxygen, metal ions), heavy asphalt-like substances - all of them are practically absent in organisms.
Oil and petroleum products are the most common pollutants in the World Ocean.
The routes of entry and forms of existence of petroleum hydrocarbons are diverse (dissolved, emulsified, film, solid). M.P. Nesterova (1984) notes the following admission routes:
discharges in ports and port waters, including losses when loading tanker tankers (17%~);
Discharge of industrial waste and wastewater (10%);
Stormwater (5%);
Disasters of ships and drilling rigs at sea (6%);
Offshore drilling (1%);
Atmospheric fallout (10%)",
Removal by river runoff in all its diversity of forms (28%).
Discharges of washing, ballast and bilge waters into the sea from ships (23%);
The greatest oil losses are associated with its transportation from production areas. Emergencies such as tankers discharging washing and ballast water overboard - all this causes the presence of permanent fields of pollution along sea routes.
A 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 for remote detection and assessment of oil pollution on the sea surface in the ultraviolet, visible and infrared parts of the spectrum. Passive and active methods are used for this. Large masses of oil from land enter the seas through rivers, with domestic and storm drains.
The fate of oil spilled at sea is determined by the sum of the following processes: evaporation, emulsification, dissolution, oxidation, formation of oil aggregates, sedimentation and biodegradation.
When oil enters the marine environment, it first spreads as a surface film, forming slicks of varying thickness. By the color of the film you can approximately estimate its thickness. The oil film changes the intensity and spectral composition of light penetrating into the water mass. The light transmittance of thin films of crude oil is 1-10% (280 nm), 60-70% (400 nm). An oil film 30-40 microns thick completely absorbs infrared radiation.
During the first period of existence of oil slicks, the process of evaporation of hydrocarbons is of great importance. According to observational data, 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 low solubility in water, which decreases with increasing number of carbon atoms in the molecule. About 10 mg of compounds with C6, 1 mg of compounds with C8 and 0.01 mg of compounds with C12 are dissolved in 1 liter of distilled water. For example, at average seawater temperature, 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 to aquatic organisms. These 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 removing 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 amount to 5-10%. Highly viscous structured formations - “chocolate mousse” and oil lumps - can remain on the sea surface for a long time, be transported by currents, washed ashore and settle to the bottom. Oil lumps are often colonized by periphyton (blue-green algae and diatoms, barnacles and other invertebrates).
Pesticides constitute a large group of artificially created substances used to combat pests and plant diseases. Depending on their 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, every ruble spent for chemical protection of plants from pests and diseases, ensures the preservation of the harvest and its quality when cultivating grain and vegetable crops for an average of 10 rubles, technical and fruit crops - up to 30 rubles. At the same time, environmental studies have established that pesticides, while destroying crop pests, cause enormous harm to many beneficial organisms and undermine the health of natural biocenoses. In agriculture, there has long been a problem of transition 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 become part of terrestrial and marine ecosystems by aeolian or waterborne means. Industrial production of pesticides is accompanied by the emergence of a large number of by-products that pollute wastewater.
Representatives of insecticides, fungicides and herbicides are most often found in the aquatic environment.
Synthesized insecticides are divided into three main groups: organochlorine, organophosphorus and carbamates.
Organochlorine insecticides are produced 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 in the joint presence increases, all kinds of chlorinated cyclodiene derivatives (eldrin, dil-drin, heptachlor, etc.), as well as numerous isomers of hexachlorocyclohexane (y -HCH), of which lindane is the most dangerous. These substances have a half-life of up to several decades and are very resistant to biodegradation.
Polychlorinated biphenyls (PCBs), derivatives of DDT without an aliphatic part, containing 210 theoretical homologues and isomers, are often found in the aquatic environment.
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 the combustion of solid waste in landfills. The latter source supplies PCBs into the atmosphere, from where they fall with precipitation in all regions of the globe. Thus, in snow samples taken in Antarctica, the PCB content was 0.03 - 1.2 ng/l.
Organophosphate pesticides are esters of various alcohols of orthophosphoric acid or one of its derivatives, thiophosphoric acid. This group includes modern insecticides with characteristic selectivity of action towards insects. Most organophosphates are subject to fairly rapid (within a month) biochemical decomposition in soil and water. More than 50 thousand active substances have been synthesized, of which parathion, malathion, fosalong, and dursban are especially famous.
Carbamates are, as a rule, esters of n-metacarbamic acid. Most of them also have selectivity of action.
Copper salts and some mineral sulfur compounds were previously used as fungicides used to combat fungal diseases of plants. Then organomercury substances such as chlorinated methylmercury found widespread use, which, due to its extreme toxicity to animals, was replaced by methoxyethyl mercury 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 that are quite soluble in water and stable in soils. The most powerful of all herbicides is pichloram. To completely destroy some plant species, only 0.06 kg of this substance per 1 hectare 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 a large group of substances that reduce the surface tension of water. They are part of synthetic detergents (CMC), widely used in everyday life and industry. Together with wastewater, surfactants enter 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 (persulfates, perborates), soda ash, carboxymethylcellulose, sodium silicates and others.
The molecules of all surfactants consist of hydrophilic and hydrophobic parts. The hydrophilic part is the 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, containing 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 molecule, surfactants are divided into anionic (organic ion is negatively charged), cationic (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 hydrogen bonds between water molecules and oxygen atoms included in the polyethylene glycol radical of the surfactant.
The most common surfactants are anionic substances. They account for more than 50% of all surfactants produced in the world. The most common are alkylaryl sulfonates (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 alkyl naphthalene sulfonates 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 processes such as flotation concentration of ores, separation of chemical technology products, production of polymers, improving conditions for drilling oil and gas wells, and combating equipment corrosion.
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.
Carcinogens- these are chemically homogeneous compounds that exhibit transforming activity and can cause carcinogenic, teratogenic (disruption of embryonic development processes) or mutagenic changes in organisms. Depending on the conditions of exposure, 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 organic compounds in the molecules of which the benzene ring is the main structural element. Numerous unsubstituted PAHs contain from 3 to 7 benzene rings in the molecule, variously connected to each other. There are also a large number of polycyclic structures containing a functional group either on the benzene ring or on the side chain. These are halogen-, amino-, sulfo-, nitro derivatives, as well as alcohols, aldehydes, ethers, 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 virtually no effect on the solubility of PAHs. However, in the presence of benzene, oil, petroleum products, detergents and other organic substances, the solubility of PAHs increases sharply. Of the group of unsubstituted PAHs in natural conditions, 3,4-benzpyrene (BP) is the most known and widespread.
Sources of PAHs in the environment can be natural and anthropogenic processes. 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 be released into 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 effects.
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 BP content 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 estimates by 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 water 0.0001 µg/l. Accordingly, gradations of the degree of pollution of environmental objects are 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 fuels. Pyrolytic formation of PAHs occurs at temperatures of 650-900 °C and a lack of oxygen in the flame. The formation of BP was observed during the pyrolysis of wood with maximum yield at 300-350 °C (Dikun, 1970).
According to M. Suess (G976), global BP emissions in the 70s were 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 processes, therefore, despite 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. For marine biocenoses, the most dangerous are mercury, lead and cadmium.
Mercury is transported to the ocean by continental runoff and through the atmosphere. During the weathering of sedimentary and igneous rocks, 3.5 thousand tons of mercury are released annually. Atmospheric dust contains about 12 thousand tons of mercury, a significant part of which is of anthropogenic origin. As a result of volcanic eruptions and atmospheric precipitation, 50 thousand tons of mercury enter the ocean surface annually, and during degassing of the lithosphere - 25-150 thousand tons. About half of the annual industrial production of this metal (9-10 thousand tons/year) in various ways falls into the ocean. The mercury content in coal and oil averages 1 mg/kg, so 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 suspended matter increases greatly. 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 in coastal populations. By 1977, there were 2,800 victims of Minamata disease in Japan. The cause was waste from plants producing vinyl chloride and acetaldehyde, which used mercury chloride as a catalyst. Insufficiently treated wastewater from factories flowed into Minamata Bay.
Lead is a typical trace element found in all components of the environment: rocks, soils, natural waters, atmosphere, living organisms. Finally, lead is actively dissipated into the environment during human economic activity. These are emissions from industrial and domestic wastewater, from smoke and dust from industrial enterprises, and from exhaust gases from internal combustion engines.
According to V.V. Dobrovolsky (1987), the redistribution of lead masses between land and the World Ocean has the following form. C. river runoff at an average concentration of lead in water of 1 μg/l carries about 40 10 3 t/year of water-soluble lead into the ocean, approximately 2800-10 3 t/year in the solid phase of river suspended matter, and 10 10 3 t/year in fine organic detritus. /year. If we take into account that more than 90% of river suspended matter settles in the narrow coastal strip of the shelf and a significant part of the water-soluble metal compounds is captured by iron oxide gels, then as a result the pelagic ocean receives only about (200-300) 10 3 tons in the composition of fine suspended matter and (25- 30) 10 3 t of dissolved compounds.
The migration flow of lead from the continents to the ocean occurs 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 supply to the ocean surface with liquid precipitation is estimated at (400-2500) 10 3 t/year with a concentration in rainwater of 1-6 μg/l. Sources of lead entering the atmosphere are volcanic emissions (15-30 t/year in pelitic eruption products and 4 10 3 t/year in submicron particles), volatile organic compounds from vegetation (250-300 t/year), combustion products during fires ((6-7) 10 3 t/year) and modern industry. Lead production increased from 20-10 3 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. The current release of lead into the environment through industrial and household waste is estimated at (100-400) 10 3 tons/year.
Cadmium, whose global production reached 15 10 3 tons/year in the 70s, also enters the ocean through river runoff and through the atmosphere. The volume of atmospheric removal of cadmium, according to various estimates, is (1.7-8.6) 10 3 tons/year.
Dumping of waste into the sea for the purpose of burial (dumping). Many countries with access to the sea carry out marine disposal of various materials and substances, in particular dredging soil, drill cuttings, industrial waste, construction waste, solid waste, explosives and chemicals, radioactive waste, etc. Volume burials account for about 10% of the total mass of pollutants entering the World Ocean. Thus, from 1976 to 1980, more than 150 million tons of various waste were dumped annually for the purpose of disposal, which is what defines the concept of “dumping.”
The basis for dumping at sea is the ability of the marine environment to process large quantities of organic and inorganic substances without much damage to water quality. However, this ability is not unlimited. Therefore, dumping is seen as a forced measure, a temporary tribute from society to the imperfection of technology. 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 waste on average contains (by dry matter weight) 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 (by 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 contaminated with heavy metals. Dredging materials also have a similar composition.
During discharge, when the material passes through a column of water, part of the pollutants goes into solution, changing the quality of the water, while the other 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, dissolution of suspended matter, accumulation of metals in dissolved form, and the appearance of hydrogen sulfide. The presence of a large amount of organic substances creates a stable reducing environment in the soil, in which a special type of silt water appears, containing hydrogen sulfide, ammonia, and metal ions in reduced form. In this case, sulfates and nitrates are reduced, and phosphates are released.
Organisms of the neuston, pelagic and benthos 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 suspended pollutants in water worsens the conditions of nutrition, respiration and metabolism of aquatic organisms, reduces the growth rate, and inhibits sexual maturation of planktonic crustaceans. Pollutants entering the solution can accumulate in the tissues and organs of aquatic organisms and have a toxic effect on them. The discharge of dumping materials to the bottom and prolonged increased turbidity of the bottom water lead to the backfilling and death from suffocation of attached and sedentary forms of benthos. In surviving fish, mollusks and crustaceans, their growth rate is reduced due to deteriorating feeding and breathing conditions. The species composition of the benthic community often changes.
When organizing a control system for waste discharges into the sea, the determination of dumping areas taking into account the properties of materials and the characteristics of the marine environment is crucial. 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 Dumping Convention, 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 discharge areas, taking into account the requirements for maximum dilution of substances, minimum distribution beyond the discharge limits, and a favorable combination of hydrological and hydrophysical conditions.
3. Ensuring the remoteness of discharge areas from fish feeding and spawning areas, from habitats of rare and sensitive species of aquatic organisms, 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 extra-systemic unit of radioactivity curie (Ci), corresponding to the activity of an isotope in which 3.7-10 10 decay events occur in 1 s, was widely used.
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 industrial production of fissile materials and radioactive nuclides. Three groups of sources are identified: 1) nuclear weapons testing, 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 short half-lives, although detectable in water and marine organisms after an explosion, are almost never found in global radioactive fallout. Here, primarily 90 Sr and 137 Cs are present with a half-life of about 30 years. The most dangerous radionuclide from the unreacted remnants of nuclear charges is 239 Pu (T 1/2 = 24.4-10 3 years), very toxic as a chemical substance. As fission products 90 Sr and 137 Cs decay, it becomes a major component of pollution. By the time of the moratorium on atmospheric testing 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 external environment. The main products of nuclear reactions with neutrons in the marine environment are radioisotopes of sodium, potassium, phosphorus, chlorine, bromine, calcium, manganese, sulfur, zinc, originating from elements dissolved in sea water. This is induced activity.
Most of the radionuclides entering the marine environment have analogues that are constantly present in water, such as 239 Pu, 239 Np, 99 T C) transplutonium are not characteristic of the composition of sea water, and the living matter of the ocean must adapt to them anew.
As a result of nuclear fuel reprocessing, a significant amount of radioactive waste appears in liquid, solid and gaseous forms. The bulk of waste consists of radioactive solutions. Given the high cost of processing and storing concentrates in special storage facilities, some countries prefer to pour waste into the ocean with river flow or dump it in concrete blocks on the bottom of deep ocean trenches. Reliable concentration methods have not yet been developed for the radioactive isotopes Ar, Xe, Em and T, so they can end up in 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 humans 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 aquatic organisms in certain areas of the ocean.
2 Anthropogenic ocean ecology–a new scientific direction in oceanology. As a result of anthropogenic impact in the ocean, additional environmental factors arise 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. These include anthropogenic ocean ecology. This new direction is designed to study the mechanisms of response of organisms 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 anthropogenic ocean ecology is changes 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 zonality and the degree of anthropogenic impact.
Anthropogenic ocean ecology uses the following methods of analysis for its purposes: genetic (assessment of carcinogenic and mutagenic hazards), cytological (study of the cellular structure of marine organisms in normal and pathological states), microbiological (study of the adaptation of microorganisms to toxic pollutants), environmental (knowledge of the patterns of formation and the development of populations and biocenoses in specific living conditions in order to predict their condition in changing environmental conditions), ecological-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 the scientific basis for determining critical levels of pollutants in marine ecosystems, assessing the assimilation capacity of marine ecosystems, normalizing anthropogenic impacts on the World Ocean, as well as creating mathematical models of environmental processes to predict environmental situations in the ocean.
Knowledge about the most important environmental phenomena in the ocean (such as production and destruction processes, the passage of biogeochemical cycles of pollutants, etc.) is limited by a lack of information. This makes it difficult to predict the environmental situation in the ocean and implement environmental measures. Currently, environmental monitoring of the ocean is of particular importance, the strategy of which is focused on long-term observations in certain areas of the ocean in order to create a data bank covering global changes in ocean ecosystems.
3 The concept of assimilative 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 amount of pollutants) and for the m-th ecosystem - this is the maximum dynamic capacity of such a quantity of pollutants (in terms of the entire zone or unit volume of the marine ecosystem) that can be accumulated, destroyed, transformed (by biological or chemical transformations) per unit of time ) and removed through the processes of sedimentation, diffusion or any other transfer beyond the volume of the ecosystem without disrupting its normal functioning.
The total removal (A i) of a pollutant from a marine ecosystem can be written as
where K i is a safety factor reflecting the environmental conditions of the pollution process in various zones of the marine ecosystem; τ i is the 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. From here, the assimilation capacity can be estimated using formula (1) at ;.
All quantities included in the right side of equation (1) can be directly measured using data obtained in the process of long-term comprehensive 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) calculation of mass balances and lifetime of pollutants in the ecosystem, 2) analysis of the biotic balance in the ecosystem, and 3) assessment of critical concentrations of the impact of pollutants (or environmental MPCs ) on the functioning of biota.
To address issues of environmental regulation of anthropogenic impacts on marine ecosystems, the calculation of assimilation capacity is the most representative, since it takes into account the assimilation capacity of the maximum permissible environmental load (MPEL) of a polluting reservoir and is calculated quite simply. Thus, under a stationary regime of reservoir pollution, PDEN will be equal to the assimilation capacity.
4 Conclusions from the assessment of the assimilation capacity of the marine ecosystem for pollutants using the example of the Baltic Sea. Using the example of the Baltic Sea, the assimilation capacity values for a number of toxic metals (Zn, Cu, Pb, Cd, Hg) and organic substances (PCBs and BP) were calculated (Izrael, Tsyban, Ventzel, Shigaev, 1988).
The average concentrations of toxic metals in seawater turned out to be one to two orders of magnitude lower than their threshold doses, and the concentrations of PCBs and BPs were only an order of magnitude lower. Hence, the safety factors for PCBs and BP turned out to be less than for metals. At the first stage of the work, the authors of the calculation, using materials from long-term environmental studies in the Baltic Sea and literary sources, determined the concentrations of pollutants in the components of the ecosystem, the rate of biosedimentation, the flow 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 substances in question 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 genetic monitoring system for the Baltic Sea.
At the second stage of research, it was shown that the most sensitive element of 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 a “target” process. Therefore, threshold doses of pollutants established for phytoplankton are used here.
Estimates of the assimilation capacity of zones in the open part of the Baltic Sea show that the existing runoff of zinc, cadmium and mercury is, respectively, 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 threat 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 assimilation capacity, but PCB exceeds it. The latter indicates an urgent need to further reduce PCB discharges into the Baltic Sea.
With three-quarters of the world's population living in coastal areas, it is not surprising that the world's oceans are suffering from the effects of human activity and widespread pollution. The high tide zone is disappearing due to the construction of factories, port facilities, and tourist complexes. The water area is constantly polluted by domestic and industrial wastewater, pesticides, and hydrocarbons. Heavy metals were found in the bodies of deep-sea (3 km) fish and Arctic penguins. Every year, rivers bring about 10 billion tons of waste into the ocean, sources silt up, and the oceans bloom. Each such environmental problem requires a solution.
Ecological disasters
Pollution of water bodies manifests itself in a decrease in their ecological significance and biosphere functions under the influence of harmful substances. It leads to changes in organoleptic (transparency, color, taste, smell) and physical properties.
The following are present in large quantities in water:
- nitrates;
- sulfates;
- chlorides;
- heavy metals;
- radioactive elements;
- pathogenic bacteria, etc.
In addition, oxygen dissolved in water is significantly reduced. More than 15 million tons of petroleum products alone end up in the ocean every year, as disasters constantly occur involving oil tankers and drilling rigs.
A huge number of tourist ships dump all their waste into the seas and oceans. A real environmental disaster is radioactive waste and heavy metals that enter the water area as a result of the burial of chemicals and explosives in containers.
Wrecks of large tankers
Transporting hydrocarbons can result in a shipwreck and an oil spill on a vast water surface. Its annual release into the ocean accounts for more than 10% of global production. To this we must add leaks during production from wells (10 million tons), and processed products coming with storm drains (8 million tons). 
Tanker disasters caused enormous damage:
- In 1967, the American ship Torrey Canyon off the coast of England - 120 thousand tons. The oil burned for three days.
- 1968–1977 – 760 large tankers with massive release of oil products into the ocean.
- In 1978, the American tanker Amono Codis off the coast of France - 220 thousand tons. Oil covered an area of 3.5 thousand square meters. km. water surface and 180 km of coastline.
- In 1989, the ship "Valdis" off the coast of Alaska - 40 thousand tons. The oil slick had an area of 80 square meters. km.
- In 1990, during the Kuwait War, Iraqi defenders opened oil terminals and emptied several oil tankers to prevent American troops from landing. More than 1.5 million tons of oil covered a thousand square meters. km of the Persian Gulf and 600 km of coastline. In response, the Americans bombed several more storage facilities.
- 1997 – wreck of the Russian ship “Nakhodka” on the China-Kamchatka route – 19 thousand tons.
- 1998 - the Liberian tanker Pallas ran aground off the European coast - 20 tons.
- 2002 – Spain, Bay of Biscay. Tanker "Prestige" - 90 thousand tons. The cost of eliminating the consequences amounted to over 2.5 million euros. After this, France and Spain banned oil tankers without a double hull from entering their waters.
- 2007 – storm in the Kerch Strait. 4 ships sank, 6 ran aground, 2 tankers were damaged. The damage amounted to 6.5 billion rubles.
Not a single year passes on the planet without a catastrophe. The oil film is capable of completely absorbing infrared rays, causing the death of marine and coastal inhabitants, which leads to global environmental changes.
Another dangerous water pollutant is wastewater. Large coastal cities that cannot cope with the flow of sewage waste are trying to divert sewer pipes further into the sea. From mainland megacities, wastewater flows into rivers.
Heated waste water discharged by power plants and industries is a factor in the thermal pollution of water bodies, which can significantly increase the surface temperature.
It prevents the exchange of bottom and surface water layers, which reduces the supply of oxygen, increases the temperature and, as a result, the activity of aerobic bacteria. New species of algae and phytoplankton appear, which leads to water blooms and disruption of the biological balance of the ocean.
An increase in the mass of phytoplankton threatens the loss of the species gene pool and a decrease in the ability of ecosystems to self-regulate. Accumulations of small algae on the surface of seas and oceans reach such sizes that spots and stripes of them are clearly visible from space. Phytoplankton serves as an indicator of the disappointing ecological state and dynamics of water masses.
Its vital activity leads to the formation of foam, a chemical change in composition and water pollution, and mass reproduction changes the color of the sea.
It acquires red, brown, yellow, milky white and other shades. For the color to change, the population needs to reach a million per liter.
Blooming plankton contributes to the massive death of fish and other marine animals, since it actively consumes dissolved oxygen and releases toxic substances. The explosive proliferation of such algae causes “red tides” (Asia, USA) and covers large areas.
Algae (spirogyra), which is unusual for Lake Baikal, has grown abnormally as a result of the extensive discharge of chemicals through wastewater treatment plants. They were thrown onto the coastline (20 km), and the mass was 1,500 tons. Now locals call Baikal black because the algae are black and, when dying, emit a monstrous stench.
Plastic pollution
Plastic waste is another factor in ocean pollution. They form entire islands on the surface and threaten the lives of marine life.
Plastic does not dissolve or decompose and can last for centuries. Animals and birds mistake it for something edible and swallow cups and polyethylene, which they cannot digest, and die.
Under the influence of sunlight, plastic is crushed to the size of plankton and, thus, already participates in food chains. The shellfish attach themselves to bottles and ropes, sinking them to the bottom in large numbers.
Garbage islands can be considered a symbol of ocean pollution. The largest garbage island is located in the Pacific Ocean - it reaches an area of 1,760,000 square meters. km and 10 m deep. The vast majority of garbage is of coastal origin (80%), the rest is waste from ships and fishing nets (20%).
Metals and chemicals
Sources of water pollution are numerous and varied - from non-degradable detergents to mercury, lead, cadmium. Together with wastewater, pesticides, insecticides, bactericides and fungicides enter the oceans. These substances are widely used in agriculture to combat diseases, plant pests and weed control. More than 12 million tons of these funds are already in the Earth's ecosystems.
A synthetic surfactant found in detergents has a detrimental effect on the ocean. It contains detergents that lower the surface tension of water. In addition, detergents consist of substances harmful to the inhabitants of ecosystems, such as:
- sodium silicate;
- sodium polyphosphate;
- soda ash;
- bleach;
- flavoring agents, etc.
The greatest danger to the oceanic biocenosis is mercury, cadmium and lead.
Their ions accumulate in representatives of marine food chains and cause their mutations, diseases and death. People also belong to part of the food chain and, by eating such “seafood”, are at great risk.
The most famous is Minamata disease (Japan), which causes visual impairment, speech impairment, and paralysis.
The cause of its occurrence was waste from enterprises producing vinyl chloride (the process uses a mercury catalyst). Poorly treated industrial waters have been flowing into Minamata Bay for a long time.
Mercury compounds settled in the bodies of shellfish and fish, which the local population widely used in their diet. As a result, more than 70 people died and several hundred people were bedridden.
The threat posed to humanity by the environmental crisis is vast and multidimensional:
- reduction in fish catch;
- eating mutated animals;
- loss of unique recreational areas;
- general poisoning of the biosphere;
- disappearance of people.
When contacting contaminated water (washing, swimming, fishing), there is a risk of penetration of all kinds of bacteria through the skin or mucous membranes, causing serious illnesses. In conditions of an environmental disaster, there is a high probability of such well-known diseases as: 
- dysentery;
- cholera;
- typhoid fever, etc.
There is also a high probability of new diseases emerging as a result of mutations due to radioactive and chemical compounds.
The world community has already begun to take measures to artificially renew the biological resources of the oceans; marine reserves and man-made islands are being created. But all this is the elimination of consequences, not causes. As long as there is a release of oil, wastewater, metals, chemicals and garbage into the ocean, the danger of the destruction of civilization will only increase.
Impact on ecosystems
As a result of thoughtless human activity, ecological systems are the first to suffer.
- Their stability is compromised.
- Eutrophication is progressing.
- Color tides appear.
- Toxins accumulate in biomass.
- Biological productivity decreases.
- Carcinogenesis and mutations occur in the ocean.
- Microbiological pollution of coastal zones occurs.
Toxic pollutants are constantly entering the ocean, and even the ability of some organisms (bivalves and benthic microorganisms) to accumulate and remove toxins (pesticides and heavy metals) cannot withstand such quantities. Therefore, it is important to determine the permissible anthropogenic pressure on hydrological ecosystems and study their assimilation capabilities for the accumulation and subsequent removal of harmful substances.
A bunch of plastic floating on the ocean waves could be used to make plastic food containers.
Monitoring ocean pollution problems
Today we can state the presence of the pollutant not only in coastal areas and shipping areas, but also in the open ocean, including the Arctic and Antarctic. The hydrosphere is a powerful regulator of the whirlpool, the circulation of air flows and the temperature regime of the planet. Its pollution can change these characteristics and affect not only flora and fauna, but also climatic conditions.
At the present stage of development, with the increasing negative impact of humanity on the hydrosphere and the loss of protective properties of ecosystems, the following becomes obvious:
- awareness of reality and trends;
- greening of thinking;
- the need for new approaches to environmental management.
Today we are no longer talking about protecting the ocean - now it needs to be cleaned up immediately, and this is a global problem of civilization.
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