Air, Water & Soil: Water Pollutants, Properties of Water, Organic and Inorganic Chemical Pollutants (For CBSE, ICSE, IAS, NET, NRA 2022)

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Introduction

  • Water is the basic requirement of all living organisms.
  • It is an inorganic, transparent, tasteless, odorless, and colorless chemical substance,
  • Chemical reactions inside the living cells occur due to water as the medium.
  • It covers 71 % of the Earth՚s surface. Oceans, seas, rivers, lakes are the major sources of water.
  • In atmosphere it is found as vapour and in snow, glaciers, etc.
  • Water is responsible for flushing out toxins and wastes from the human body thereby regulating the body temperature.

Properties of Water

Properties of Water

Organic Chemical Pollutants

  • Organic chemical pollutants including oil, gasoline, pesticides, and organic solvents.
  • Industrial discharge and runoff from farms and urban areas are the sources of these pollutants.
  • These pollutants degrade the water quality.
  • Harmful health effects are cancer, damage the central nervous system and cause birth defects in humans, etc.

Inorganic Chemical Pollutants

  • These include toxic metals such as lead, cadmium, mercury, etc.
  • Industrial discharge, chemicals in household wastewater and seepage from municipal dumps are the major source.
  • Harmful effects are cancer and birth defects, can also affect aquatic life, plant damage and metal corrosion.

Oxygen Depleting Wastes

  • This includes animal manure in feedlot and farm runoff including the urban sewage.
  • These wastes are consumed by anaerobic bacteria and their excessive growth can deplete water of dissolved oxygen.
  • Eutrophication and death of oxygen consuming aquatic animals may be caused.

Plant Nutrient Pollutants

  • These pollutants are found in urban sewage, runoff from farms and gardens including household water.
  • Excessive algae growth is caused due to too much plant nutrients in water.
  • Eutrophication in the lakes and ponds is caused due to the subsequent loss of dissolved oxygen.

Radioactive Materials

  • Ionizing radiation can cause cancers, especially in the thyroid and bone.
  • These materials me get introduced into food chain through plants.
  • Further they become incorporated in body tissues of humans and animals.
  • For e. g. iodine-131 and strontium-90 which are found in nuclear power plant effluents.

Thermal Pollution

  • This is also known as Thermal enrichment.
  • Disposal of heated industrial wastewater or water from the cooling towers of nuclear power plants.
  • Dissolved oxygen may get depleted due to the increased temperature of the water thereby exceeding the range of tolerance of some aquatic species and disrupting the local ecosystem.
  • The amounts of infectious agents, oxygen-depleting wastes, inorganic chemicals, organic chemicals, and plant nutrients can be reduced by processing water in treatment plants.
  • Other ways of reducing the chemical release in the environment.
    • Bans and restrictions on chemicals.
    • For e. g. DDT and hexavalent chromium compounds.

Water Borne Diseases

Water Borne Diseases