C.m

• Sources of water


  • Hydrologic or water cycle (Evaporation, precipitation, condensation, Rain water)
  • Surface water (rivers, streams, lakes, swamps)
  • Underground water (boreholes, springs, wells)
  • Rain water (Pure or not?)
• Drinking Water can be contaminated at all levels in the water supply chain
• Everyone has the human right to safe drinking water
• Water has to be accessible, safe and sustainable
• 2.2 billion people worldwide lack access to safe drinking water
• By 2030, 1.6 billion more people will lack safely managed water
• 30% of the population in SSA use safely managed drinking water
• 11% of the population in SL have access to safely managed water
• An estimated 2.1 billion people are without access to water supplies
• 2.4 billion lack adequate sanitation
• Diarrhoea causes 2 million deaths per year, mostly amongst children under the age of five
• About a third of the population in the developing world is infected with intestinal worms
• 6 – 9 million people are estimated to be blind from trachoma
• 200 million people in the world are infected by schistosomiasis (bilharzia), 20 million of which suffer severe consequences
• SDG-6: Clean water and sanitation
• 6.1: Access to clean water
• Target: Universal and equitable access to safe and affordable drinking water for all
• 6.2: Water quality
• Target: Reduce pollution, eliminate dumping and minimize the release of hazardous chemicals
• 6.3: Water efficiency and scarcity
• Target: Sustainably increase water use efficiency
• 6.4: Integrated water Resource management
• 6.5: Protecting water ecosystem Mountains, forests wetlands rivers, lakes
• Almost half of the environmental health-related disease burden can be attributed to unsafe water and sanitation
• 48% of disease burden is attributable to Unsafe water & sanitation
• By improving drinking water and sanitation services, diarrhoeal disease morbidity could be reduced by 25 – 45%
• The proportion of all health problems or deaths in the community attributable to a risk factor is referred to as attributable fraction
• Diseases related to water supply and sanitation are mostly transmitted via a faecal-oral mechanism by pathogens found in human excreta
• Faeco-oral route is the main mode of transmission ("hygiene-related” transmission routes)
• Poorly managed sanitation – contamination of surface or affecting the quality of water underground
• Water related diseases


  • Water borne
  • Water-borne diseases are caused by pathogens in the water a person drinks (Amoebiasis, Giardiasis, Cryptosporidiosis, Shigellosis, Cholera, Typhoid)
  • Water washed
  • Water-washed diseases are diseases where transmission is facilitated by insufficient quantities of water (regardless of its quality)
  • Linked to issues of personal and domestic hygiene
  • Diseases of poor hygiene arising from direct contact e.g. Scabies, Lice, ringworm, Tropical ulcers, Dermatomycosis, Trachoma
  • Water-based diseases
  • Transmission occurs through a vector that breeds in water e.g. Malaria, onchocerciasis, schistosomiasis, dengue fever
• Microbial hazards associated with water and excreta

  • Virus infections such as rotavirus or hepatitis A and E
  • Bacterial infections such as cholera or trachoma
  • Protozoal infections such as amoebiasis
  • Infections with helminths (parasitic worms) such as Ascaris lumbricoides, hookworm, guinea worm or schistosoma
• Sources of contamination of water

  • Microorganisms
  • Chemicals-pesticides, fertilisers
  • Animal manure
  • Leaky pit latrines
  • Open defecation
  • Landfills
  • Sewage treatment plant
  • Industrial liquid waste
• Waterborne Diseases transmitted from person to person through drinking water contaminated by human or animal faeces
• Usually referred to as faeco-oral group of diseases
• Breaking the faeco-oral route is the basis of prevention and control
• Chemical contaminants - Sources

  • Naturally Occurring: from rocks, soil and geological settings
  • Industrial sources and human dwellings: from Mining, manufacturing, industries
  • Agricultural activities
• Transmission routes and barriers to disease

  • Faecal-oral
• Chemical contaminants sources


  • Naturally Occurring: from rocks, soil and geological settings
  • Industrial sources and human dwellings: from Mining, manufacturing, industries
  • Agricultural activities: Manure, fertilisers, pesticides
  • Pesticides used in Public health: from larviciding and vector control
  • Water treatment: Coagulant
• Chemical contaminants


  • Chlorine
  • Fluoride
  • Iron
  • Lead
  • Mercury