3. Ecological crisis and ecological situations

Ecological crisis - are great changes of biosphere or parts of biosphere that cause the qualitative transformation of environment and living systems.

Table: Classification of ecological crisis and ecological situations

State of nature		Ecological situations
Status	Characteristic	Type	Influence to human’s health
Natural	Is not changed by human	Successful	Environment does not affect negatively the health of people.
Balanced	Rate of regeneration processes in nature is higher or equal to the rate of anthropogenic disruption.	Successful	Environment does not affect negatively the health of people.
Crisis	Rate of anthropogenic processes is higher than the rate of the nature self-regeneration, but radical change in a system does not occur.	Tense	Health state is below the normal. There is no statistical and authentic shortening of the length of human life and the growth of the early disability .
Crucial	Inverted replacement of existent ecosystem for less productive devastation.	Tense	Health state is below the normal.
Catastrophic	Hardly inverse ecosystem. Process of devastation occurs at a large scale.	Ecological disaster	Health state is statistically below the normal.
Collapse	Not inverted of catastrophe ecosystem. lost of biological productivity by the ecosystem.	Ecological Disruption	It is not practically available for human's life (Aral region, Sahel, Chernobyl AES)

4. Modern Ecological crisis: Pollution.

• Global scale – a development of the ecological crisis at a word wide level.

• People overpopulation – a situation in which there are too many people in a given geographic area.

• Consumption overpopulation – a situation that occurs when each individual in a population consumes too large a share of resources.

• Unsustainable development

According to the Worldwatch Institute, highly developed nations (20% of the world populations) consume more than half of its resources: 86% of aluminum used, 76% of timber harvested, 68% of energy produced, 61% of meat eaten, 42% of the fresh water consumed; 75% of the world’s pollution and waste are also generated by these nations.

Pollution - is an undesirable change in the physical, chemical, or biological characteristics of an ecosystem.

Pollutants - is the accumulation of impurities in the environment.

I. Classification of pollutants: Biodegradable and nonbiodegradable.

Biodegradable pollutants (organic garbage) - subject to decay by microorganisms.

Nonbiodegradable pollutants - that cannot be decomposed by microorganisms.

II. Classification of pollutants: Primary and Secondary.

Primary pollutants - that emitted directly into the atmosphere (CO₂, CO, NO₂, Pb, SO₂, F, Cl, hydrocarbons; particulates - the tiny solid particles found in smoke).

Secondary pollutants - that result from some effect acting on primary pollutants (ozone, acid rains, photochemical smog).

Sources of pollution:

• Industrial Sources - chemical wastes in factories and processing plants and then releasing them into the air or water or storing them incorrectly.

• Hazardous wastes - those are dangerous toxic, radioactive, explosive to humans and the environment.

• Agricultural Sources - chemicals catted pesticides that are manufactured by fanners to control insects and other pests. However, pesticides can soak into the soil and flow into streams, where the> enter the food chains.

• Domestic Sources - wastes and sewage. To prevent sewage from flowing into rivers and lakes and tainting the water supply, cities have developed sewage treatment facilities to purify and recycle water.

Types of harmful agents:

Pesticides – chemicals that are manufactured by farmers to control insects and other pests (common name)

Herbicides – chemicals that kill undesirable plants.

Fungicides – chemicals that kill undesirable fungi.

Insecticides – chemicals that kill undesirable insects.

Mutagens – agents, such as chemicals or radiation, that damage or alter genetic material (DNA) in cells.

Carcinogens – substances that cause cancer.

Teratogens – chemicals or other factors that specifically cause abnormalities during embryonic growth and development.

5. Natural gas composition of the atmosphere: Nitrogen (N₂) – 78%, Oxygen (O₂) – 21%, Argon (Ar) – 1%, Carbon dioxide (CO₂) – 0,04%

Table: The main anthropogenic pollutants Notes: “+” increasing effect; “-“ decreasing effect

Changes in atmosphere	Carbon dioxide CO2	Methane CH4	Nitrogen oxides NOx	Sufur dioxide SO2	Ozone O3		Freons CFC	Parti-culates
					Strato-sphere	Tropo-sphere
Global Warming	+	+	+	–		+	+
Ozone Depletion							+
Acid Rains			+	+
Photochemical smog (Los Angeles dry smog)			+			+
Wet smog (London smog)				+				+