unit 2 evs

• Natural resources


  Resources that are provided by nature and used with or without modifications
• Types of natural resources


  • Substance
  • Energy unit
  • Natural process
• Examples of natural resources


  • water
  • forest
  • mineral
  • food
  • energy
  • land
• Classification of natural resources based on development

  • Actual
  • Potential
  • Stock
  • Reserved
• Actual resources


  Resources that have been discovered, quantified, harnessed, and are being used
• Potential resources


  Resources that are known to exist, have not been quantified and can be used for future use
• Stock resources


  Resources that have been discovered, quantified but have not been harnessed due to insufficient technologies
• Reserved resources


  Natural resources that have been identified and quantified but have not been harnessed because they are being reserved for future use
• Classification of natural resources based on origin


  • Biotic
  • Abiotic
• Biotic natural resources


  Resources that come from organic matter or living things
• Abiotic natural resources


  Resources that come from non-living things or inorganic matter including the lithosphere, atmosphere, and hydrosphere
• Classification of natural resources based on stock available

  • Renewable
  • Non-renewable
• Renewable resources


  Resources that can be replenished, where the rate of replenishment exceeds the rate of use
• Non-renewable resources


  Resources that are limited and can be exhausted, where their formation takes millions of years
• ¾ th part of planet is covered with water
• 97% of water is salty, 3% is fresh water (2% glaciers, 1% is available)
• Types of water resources


  • Surface water resources
  • Groundwater resources
• Water

  • Temp. (0c- 100c)
  • Highest specific heat
  • High latent heat
  • High surface tension
  • Universal solvent
  • Unique temp./density relationship (3.94C max)
• Uses of water


  • Agriculture, 85%
  • Industries- 9%
  • Domestic- 6%
• Ground water usage


  • Subsidence - sinking of the ground due to underground material movement as sediments get compacted
  • Lowering of water table - due to withdrawal of ground water faster than it can be recharged
  • Waterlogging - excessive irrigation on poorly drained soil where water can not penetrate deeply
  • Saltwater intrusion - saltwater from the sea flows into freshwater aquifers
  • Pollution
• Water conservation methods


  • Water conservation at home
  • Conservation of water in the agriculture sector- drip irrigation and sprinklers
  • Reducing water demand by- Mulching, soli covered by crops, contour farming in hilly areas, salt resistant varieties of crop, transfer of water from surplus area to deficit area, planting trees, desalination technologies
  • Water conservation in the yard and garden
  • Rainwater harvesting
• Rainwater harvesting


  The process of collecting and storing rain instead of letting it run off
• Components of rainwater harvesting


  • Catchment: Collects and stores the rainwater
  • Conveyance system: Transports the water from the catchment to the recharge zone
  • Flush: Flushes out the first rain
  • Filter: Removes pollutants from the collected rainwater
  • Tanks and recharge structures: Store the filtered water
• Types of water-borne diseases


  • Pathogenic - due to microorganism like Bacteria, Virus, Protozoa
  • Due to Chemical - Fluorosis, Arsenicosis
• Fluorosis


  WHO has regulated the upper limit for fluoride in drinking water to be 1.5 mg/L, high conc. Upto 10mg/L causes dental and skeletal fluorosis, can also cause arthritis, bone damage, osteoporosis, muscular damage, fatigue, joint-related problems, and chronicle issues, and damage to heart, arteries, kidney, liver, endocrine glands, neuron system
• Nalgonda Technique


  It can remove more than 90% of fluoride in water, uses aluminum sulfate (a coagulant normally used for water treatment) to flocculate fluoride ions present in the drinking water, developed by National Environmental Engineering Research Institute (NEERI), Nagpur in 1961
• Arsenicosis


  Arsenic is introduced into soil and groundwater during weathering of rocks and minerals followed by subsequent leaching and runoff, or from anthropogenic sources, limit: 0.01-0.05 mg/L, can cause cancer and skin diseases, cardiovascular disease and diabetes
• Solutions for Arsenicosis

  • Safe water supply
  • RO
  • Coagulation-Flocculation
  • Activated Alumina
  • Ion exchange
  • Oxidation followed by filtration
• Water-induced diseases


  • Waterborne diseases
  • Water-induced diseases (vector borne)
• Prevention of vector borne water-induced diseases


  • Use of Indoor Residual Spray (IRS) with insecticides
  • Reduce surface water contamination
  • Use of chemical larvicides like Abate in potable water
  • Aerosol space spray during daytime
  • Malathion fogging during outbreaks
  • Use of mosquito repellent creams, liquids, coils, mats
  • Wearing clothes that cover maximum surface area of the body
• Prevention of waterborne diseases


  • Store water in a clean vessel and use boiled and cooled water for drinking
  • Disinfection using Chlorine tablets for household use
  • Maintain hygiene
  • Safe sanitation methods
  • Use RO/ filtered water