Environmental Pollution: Water and Air Contamination

Posted on Jan 31, 2025 in Geology

Contamination

Water Contamination

Contamination of waters, rivers, seas, and swamps.

Organic Waste

A river is polluted when organic waste is dumped into it. Sources include sewage and agricultural industries (dairy, farm animals, oil production).

Discharged organic matter is degraded by decomposers, which consume a lot of oxygen. This greatly increases the Biochemical Oxygen Demand (BOD), causing fish kills that further aggravate the problem.

Eutrophication

This problem occurs when phosphates are poured into the river. Phosphates are derived from detergents, soaps, and gels. The phosphates act as a fertilizer for phytoplankton.

Phytoplankton grows excessively, as does zooplankton. The water turns green and murky, potentially killing the algae.

Bioaccumulation

Dumping into a river or ocean can introduce chemical elements that are not part of biomolecules (glucose, amino acids, water). Since they are not part of biomolecules, they cannot be degraded in the cell and eliminated by the excretory organs (lungs, kidneys). The substance is deposited (accumulated) in the liver, adipose tissue, or other tissues.

What are these substances?

  • Lead
  • Mercury
  • DDT (a powerful insecticide)

Atmospheric Pollution

Ozone

What is ozone?

Ozone (O3) is formed spontaneously in the atmosphere by the reaction of molecular oxygen (O2) with atomic oxygen (O): O2 + O = O3.

Where is it found?

In the upper layers of the atmosphere.

What are its beneficial effects?

It protects us from ultraviolet rays that cause DNA mutations.

How is it destroyed?

Chemical substances containing chlorine, fluoride, and carbon are responsible for binding with and destroying ozone.

Is there a hole in the ozone layer?

There isn’t a hole as such; it’s just that the layer is much thinner in some areas, particularly over Antarctica.

What are the effects of its destruction?

It can cause cancer (especially skin cancer) and difficult-to-diagnose genetic disorders.

Acid Rain

What is acid rain?

It is water with sulfuric acid and nitric acid.

Why does it happen?

It is caused by the combustion of fossil fuels (gasoline and coal), which have remnants that contain nitrogen and sulfur. These elements are oxidized with oxygen to form nitrogen oxides and sulfur oxides, which, when combined with water, form acids.

Effects of acid rain:

  1. Acidification of soils, rivers, and lakes.
  2. Burns the leaves of plants, affecting gross and net production.
  3. Alters historic buildings, as marble and limestone dissolve.
  4. Can produce changes in the skin and mucosa, including the mucosal lining of the airways and mouth.

The Greenhouse Effect

Responsible gases: Methane, CO2, and water vapor.

Sunlight reaches the Earth. The Earth reflects back heat as infrared radiation. These gases trap some of the heat, causing a temperature rise.

  • CO2 is increasing over time.
  • An increase in the amount of CO2 is caused by:
    • Combustion of gasoline by cars.
    • Factories that emit CO2.
    • Tree felling.
    • Fires.

The greenhouse effect is responsible for climate change and global warming. Global warming could increase the soil temperature by one degree every few years. This increase could melt the polar ice caps and raise sea levels.