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POLLUTION OF NATURAL WATER
Geography teacher: Any body of water or water source is connected with its
surrounding environment. It is influenced by the conditions for the formation of
surface or underground water flow, various natural phenomena, industry, industrial
and municipal construction, transport, economic and domestic human activities. The
consequence of these influences is the introduction into the aquatic environment of
new, unusual substances - pollutants that worsen the quality of water. Pollutants
entering the aquatic environment are classified differently, depending on approaches,
criteria and objectives.
3. Geography teacher
There are chemical, physical and biological pollution.
Chemical pollution is a change in the natural chemical
properties of water due to an increase in the content of
harmful impurities in it, both inorganic (mineral salts,
acids, alkalis, clay particles) and organic (oil and oil
products, organic residues, surfactants, pesticides) .
Chemical pollution
4. Chemistry teacher: The main inorganic (mineral) pollutants of
fresh and sea waters are a variety of chemical compounds that
are toxic to the inhabitants of the aquatic environment. These
include compounds of arsenic, lead, cadmium, mercury,
chromium, copper, fluorine, etc. Most of them enter the water as
a result of human activity. Heavy metals are absorbed by the
inhabitants of rivers, lakes and seas, and then transferred along
the food chain to more highly organized representatives of the
biocenosis.
Inorganic pollution
5. Chemistry teacher: Dangerous pollutants of
the aquatic environment include inorganic
acids and bases, which determine a wide pH
range of industrial wastewater (pH from 1.0 to
11.0) and are capable of changing the pH of
the aquatic environment to values of 5.0 or
above 8.0.It is known that fish in fresh and
sea water can only exist in a slightly acidic or
slightly alkaline environment in the range of
values
pH = 5.0 - 8.5.
Currently, the discharge of purified water
into natural objects with pH = 6.5-8.5 is
permitted.
Dangerous pollutants
6. Chemistry teacher: Among the main sources of hydrosphere
pollution with minerals and nutrients, food industry enterprises
and agriculture should be mentioned. About 6 million tons of
salts are washed away from irrigated lands annually. Waste
containing mercury, lead, and copper is localized in certain
areas near the coast, but some of it is carried far beyond the
territorial waters. Mercury pollution significantly reduces the
primary production of marine and river ecosystems,
suppressing the development of phytoplankton. Waste
containing mercury usually accumulates in the bottom
sediments of bays or reservoirs. Its further migration is
accompanied by the accumulation of methyl mercury and its
inclusion in the trophic chains of aquatic organisms.
7. Not only mineral and biogenic elements, but also organic residues are
of great importance for the inhabitants of the aquatic environment.
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 bottom microorganisms involved in the process of self-
purification of water. When bottom sediments rot, toxic substances
such as hydrogen sulfide are formed, which lead to the contamination
of all water in the river. The presence of suspensions also makes it
difficult for light to penetrate deep into the water and slows down
the processes of photosynthesis.
Organic pollution
8. • One of the main sanitary requirements for water quality is
the content of the required amount of oxygen in the water.
All contaminants that in one way or another contribute to a
decrease in the oxygen content in water have a harmful
effect. Surfactants - fats, oils, lubricants - form a film on
the surface of the water. which prevents gas exchange
between water and the atmosphere, which reduces the
degree of oxygen saturation of water.
9. 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. Increasing pollution of water bodies
and drains is observed in all industrial countries. Due to the rapid pace of
urbanization and the somewhat slow construction of treatment facilities
or their unsatisfactory operation, water basins and soil are polluted by
household waste. Pollution is especially noticeable in bodies of water with
slow or non-flowing currents (reservoirs, lakes). By decomposing in the
aquatic environment, organic waste can become a breeding ground for
pathogenic organisms.
Wastewater
10. Water contaminated with organic waste becomes
practically unsuitable for drinking and other needs.
Household waste is dangerous not only because it is
the source of some human diseases (typhoid fever,
dysentery, cholera), but also because it requires a lot
of oxygen to decompose. If household wastewater
enters a body of water in very large quantities, the
content of dissolved oxygen may drop below the level
necessary for the life of marine and freshwater
organisms.
11. Oil and petroleum products are the most common pollutants. Petroleum consists
primarily of saturated aliphatic aromatic hydrocarbons.
The main components of oil - hydrocarbons (up to 98%) - are divided into 4 classes:
1. Paraffins are stable substances. Light paraffins have maximum volatility and
solubility in water.
2. Cycloparaffins are saturated cyclic compounds. The compounds are very stable
and poorly biodegradable.
3. Aromatic hydrocarbons are unsaturated cyclic compounds of the benzene series.
Oil contains volatile compounds with a molecule in the form of a single ring
(benzene, toluene, xylene), then bicyclic (naphthalene), semicyclic (pyrene).
4. Olefins are unsaturated non-cyclic compounds.
Oil and petroleum products
12. • The greatest oil losses are associated with its
transportation from production areas. Large
masses of oil enter the seas through rivers,
domestic wastewater and storm drains.
• The volume of pollution from this source is 2.0
million tons/year.0.5 million tons of oil enters
annually with industrial waste. Once in the marine
environment, oil first spreads in the form of a film,
forming layers of varying thickness. You can
determine its thickness by the color of the film. A
film 30-40 microns thick completely absorbs
infrared radiation.
13. • Pesticides are used to control plant pests. Pesticides are
divided into the following groups:insecticides - to combat
harmful insects; fungicides and bactericides - to combat
plant diseases;herbicides - against weeds.It has been
established that pesticides, while destroying pests, harm
beneficial organisms and undermine the health of
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 3 million tons. pesticides enter
the world market. About 1.5 million tons. These substances
have already become part of terrestrial and marine
ecosystems.
Pesticides
14. • Synthesized pesticides are divided into three main groups:
organochlorines, organophosphates and
carbonates.Organochlorines are obtained by chlorination of
aromatic and 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, and all kinds of chlorinated
derivatives of chlorodiene (Eldrin). These substances have a
half-life of up to several decades and are very resistant to
biodegradation.
Synthesized pesticides
15. • Polychlorinated biphenyls (PCBs), derivatives of DDT, are
often found in the aquatic environment. PCBs are used in
the production of plastics, dyes, transformers, and
capacitors. Polychlorinated biphenyls enter the environment
as a result of industrial wastewater discharges and the
combustion of solid waste in landfills.The latter source
supplies PBCs into the atmosphere, from where they fall
with precipitation in all regions of the globe, including
Antarctica.
16.
17. • They are part of synthetic detergents widely used in
everyday life and industry. Together with wastewater,
surfactants enter continental waters and the marine
environment. They contain sodium polyphosphates, as well
as a number of additional ingredients that are toxic to
aquatic organisms: fragrances, bleaching agents (persulfates,
polyborates), soda ash, carbocellulose, sodium silicates.
Surfactant molecules are divided into anionic, cationic,
amphoteric and nonionic. The most common are anionic
(more than 50%).
Synthetic surfactants (surfactants)
18. • 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.
Synthetic surfactants (surfactants)
19. • Heavy metals (mercury, lead, cadmium, zinc, copper,
arsenic) are 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.
20.
21. • Mercury is transported to the ocean by continental runoff
and through the atmosphere.The weathering of sedimentary
and igneous rocks releases 3.5 thousand tons of mercury
annually.Atmospheric dust contains about 12 thousand tons
of mercury, a significant part of which is of anthropogenic
origin.About half of the annual industrial production of
mercury (910 thousand tons / year) ends up in the ocean
through various ways.In areas polluted by industrial waters,
the concentration of mercury in solution and suspended
matter increases greatly. At the same time, some bacteria
convert chlorides into highly toxic methylmercury.
Contamination of seafood has repeatedly led to mercury
poisoning of coastal populations.
22. • Geography teacher: 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
is 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.
Dumping waste into the sea for disposal purposes
23. Geochemistry: Industrial slag contains a variety of organic
substances and heavy metal compounds. Household waste
contains organic matter, nitrogen, phosphorus, zinc, lead,
mercury, and cadmium. 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. Benthic organisms
are affected to varying degrees by the discharged materials.
Pollutants entering water can accumulate in the tissues and
organs of aquatic organisms and have a toxic effect on them.
24. • 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 sq. km. 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.
Thermal pollution
25.
26. Geography teacher: Based on a summary of the
material on hydrosphere pollution, we can
conclude:
the effects of anthropogenic impact on the aquatic
environment are manifested at the individual and
population-biocenotic levels;
the long-term effect of pollutants leads to a
simplification of the ecological system.
27. • The Earth is the most important component of the Earth's
biosphere. It is the soil shell that determines many of the
processes occurring in the biosphere. The most important
importance of soil is the accumulation of organic matter,
various chemical elements, and energy. Soil cover functions
as a biological absorber, destroyer and neutralizer of various
pollutants. If this link of the biosphere is destroyed, then the
existing functioning of the biosphere will be irreversibly
disrupted.
Soil cover
28. • One type of anthropogenic impact is pesticide pollution.
Today, 300 kg of chemicals are applied per hectare of soil
in the world. Excessive use of pesticides (herbicides,
insecticides, defoliants) negatively affects soil quality.In this
regard, the fate of pesticides in soils and the possibility of
neutralizing them by chemical and biological methods are
being intensively studied. It is very important to create
and use only drugs with a short lifespan, measured in weeks
or months. Some success has already been achieved in
this matter and drugs with a high rate of destruction are
being introduced, but the problem as a whole has not yet
been solved.
Soil cover
29. One of the most pressing global problems of
our time and the foreseeable future is the
problem of increasing acidity of atmospheric
precipitation and soil cover. Areas of acidic
soils do not experience droughts, but their
natural fertility is reduced and unstable; They
are quickly depleted and their yields are low.
Acid rain causes not only acidification of
surface waters, but also of the upper soil
horizons. Acidity with downward flows of
water spreads across the entire soil profile
and causes significant acidification of
groundwater. Acid rain occurs as a result of
human economic activity, accompanied by
the emission of colossal amounts of oxides of
sulfur, nitrogen, and carbon.
ACID PRECIPITATION
30. • Acid oxides, entering the atmosphere, are transported over
long distances, interact with water and are converted into
solutions of a mixture of sulphurous, sulfuric, nitrous, nitric
and carbonic acids, which fall in the form of “acid rain” on
land, interacting with plants, soils, and waters. The main
sources in the atmosphere are the combustion of shale, oil,
coal, and gas in industry, agriculture, and everyday life.
Human economic activity has almost doubled the release of
oxides of sulfur, nitrogen, hydrogen sulfide and carbon
monoxide into the atmosphere.
Acid oxides
