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Water quality standard

Water quality and its standards are essential for health policy.

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Water quality standard

  3. 3. INTRODUCTION • A report prepared by the World Health Organization in cooperation with the World Bank showed that in 1975, some 1230 million people were without safe water supplies. These appalling facts were central to the United Nations decision to declare an International Drinking Water Supply and Sanitation decade, beginning in 1981. • Further, the VI Five-Year Plan of India(1980-85) had made a special provision for availability of safe Drinking water for the masses. Therefore, the standard was prepared with the objective of assessing the quality of water resources, and to check the effectiveness of water treatment and supply by the concerned authorities.
  4. 4. INTRODUCTION • During VII Five-Year Plan(1985-1989), 55 mini mission districts were identified with a view to meet supply of water to all the problem villages. • The VIII Five-Year Plan(1992-1997) intended to provide safe drinking water to the rural masses. It also proposed to ensure supply of desired quality and required quantity of drinking water. • Routine surveillance of drinking water supplies must be carried out by the relevant authorities to understand the risk of specific pathogens and to define proper control procedures. Precautions/care should be taken to prevent contamination of drinking water from chlorine resistant parasites such as cryptosporidium species and giardia.
  5. 5. SAFE AND WHOLESOME WATER • Free from pathogenic agents. • Free from harmful chemical substances. • Pleasant to the taste i.e. free from colour and odour •Usable for domestic purposes.
  6. 6. WATER REQUIREMENT •RURAL AREAS: necessary minimum standard – 40 Lpcd source should be within-- 1.6 Km •URBAN AREAS: piped supply without sewerage – 70 Lpcd piped supply with sewerage – 135Lpcd metropolitan – 150 Lpcd
  7. 7. Millennium development goals : GOAL 7 : Ensure environment stability. TARGET 7.C : Halve, by 2015, the proportion of people without sustainable access to safe drinking water and basic sanitation. INDICATOR 7.8 : Proportion of population with sustainable access to an improved water source, urban and rural.
  8. 8. • Global progress towards the MDG target: trend in use of improved drinking-water • sources 1990-2008, projected to 2015
  9. 9. COUNTRY DATA-DLHS DLHS-3 (2007-08) DLHS-2 (2002-04) TOTAL RURAL URBAN TOTAL RURAL URBAN Improved Source of Drinking Water (%) 96.0 94.7 99.5 61.8 52.8 84.0
  10. 10. ESTIMATED BURDEN OF DIARRHOEA IN DALY’s 35000 30000 25000 20000 15000 10000 5000 0 DALYs (000s) by diarhoeal disease in WHO Regions, estimates for 2004
  11. 11. Diarrhoeal diseases in India: Estimated DALYs lost DALY: Disability-Adjusted Life-Year NATIONAL INSTITUTE OF CHOLERA AND ENTERIC DISEASES, KOLKATA
  12. 12. • The health burden of poor water quality is enormous. It is estimated that around 37.7 million Indians are affected by waterborne diseases annually, 1.8 million children are estimated to die of diarrhoea alone and 73 million working days are lost due to waterborne disease each year. The resulting economic burden is estimated at $600 million a year. • While ‘traditional diseases’ such as diarrhoea continue to take a heavy toll, 66 million Indians are at risk due to excess fluoride and 10 million due to excess arsenic in groundwater.
  13. 13. Framework for Safe Drinking-Water: Requirements •Health-based targets • System assessment •Operational monitoring •Management plan and monitoring plans - describing actions to be taken in normal operation and incident conditions •A system of independent surveillance
  14. 14. Health based targets •Mark out milestones to guide and chart progress towards a predetermined health and/or water safety goal. • Provides opportunity to take action to correct deficiencies. • Identifies data needs and discrepancies.
  15. 15. Types of health-based targets Health outcome targets : •Measures reduction in detected disease incidence or prevalence. •Microbial or chemical hazards with high measurable disease burden largely water associated. For eg. Flouride.
  16. 16. Water quality targets (WQTs): • Established for individual drinking-water constituents that represent a health risk from long-term exposure and where fluctuations in concentration are small or occur over long periods. • Expressed as guideline values (concentrations) of the substances or chemicals of concern.
  17. 17. Performance targets: • Employed for constituents where short-term exposure represents a public health risk or where large fluctuations in numbers or concentration can occur over short periods with significant health implications. •Most frequently applied to the control of microbial hazards in piped supplies varying from small to large.
  18. 18. Specified technology targets: •National regulatory agencies establish targets for specific actions for smaller municipal, community and household drinking-water supplies. • Identify specific permissible devices or processes for given situations and/or for generic drinking-water system types.
  19. 19. Water safety plans A WSP comprises of the three essential actions that are the responsibility of the drinking-water supplier in order to ensure that drinking-water is safe. ■ a system assessment. ■ effective operational monitoring; and ■ management. guided by health-based targets and overseen through drinking-water supply surveillance.
  20. 20. Water safety plans The primary objectives of a WSP in ensuring good drinking-water supply practice are :  Minimization of contamination of source waters.  Reduction or removal of contamination through treatment processes.  Prevention of contamination during storage, distribution and handling of drinking-water.
  21. 21. System assessment and design •Multidisciplinary team of experts with a thorough understanding of the drinking water system. • For eg. engineers, catchment & water managers, water quality specialists, environmental or public health or hygienist professionals, operational staff and representatives of consumers.
  22. 22. • Provides an overview description of the drinking-water system, including characterization of the source, identification of potential pollution sources in the catchment, measures for resource and source protection, treatment processes, storage and distribution infrastructure.
  23. 23. Operational monitoring The objectives of operational monitoring are for the drinking-water supplier to monitor each control measure in a timely manner to enable effective system management and to ensure that health-based targets are achieved.
  24. 24. Parameters used in operational monitoring • For source waters- Turbidity UV absorbency Algal growth Flow and retention time Colour, conductivity and local meteorological events
  25. 25. • For treatment- Disinfectant concentration and contact time UV intensity pH Light absorbency Membrane integrity Turbidity and Colour
  26. 26. • In piped distribution systems-- Chlorine residual monitoring -- A sudden disappearance of an otherwise stable residual can indicate ingress of contamination. Faecal indicator bacteria Pressure measurement and turbidity are also useful in operational monitoring.
  27. 27. Management procedures • Effective management implies definition of actions to be taken in response to variations that occur during normal operational conditions; of actions to be taken in specific incident situations where a loss of control of the system may occur; and of procedures to be followed in unforeseen and emergency situations. •Management procedures should be documented alongside system assessment, monitoring plans, supporting program and communication required to ensure safe operation of the system.
  28. 28. Water quality control • To ensure that water services meet agreed national standards & institutional targets. • Provides valuable information:  Quality of source of water.  Efficiency of treatment and water quality variables.  Natural and seasonal variations.  Identifies need for taking remedial action.
  29. 29. Water quality Surveillance “The continuous and vigilant public health assessment and review of the safety and acceptability of drinking-water supplies” (WHO, 1976). •Done by independent agency (state public health department). • Investigates the activity and identifies the corrective or preventive measures and gives feedback to water supplying agency.
  30. 30. • This surveillance contributes to the protection of public health by promoting improvement of the quality, quantity, accessibility, coverage, affordability and continuity of water supplies (known as service indicators). • Complementary to the quality control function.
  31. 31. Effective surveillance includes: •Regular testing of residual chlorine at consumer level. •Regular collection of water samples and testing of water samples for E. coli or thermotolerant bacteria and coliform count. •Regular interaction with supplying agency. •Monitor water borne diseases for early warning.
  32. 32. •Monitor outbreaks of water borne diseases. • Sanitary inspection. • Education of safe water to people. • Training of community members and PRI for home and well chlorination. • Intersectoral coordination.
  33. 33. Sanitary inspection •On-site inspection and evaluation by qualified individuals of all conditions, devices, and practices in the water supply system that pose an actual danger to the health and well being of the consumers.
  34. 34. Water sampling and analysis Minimum level of analysis should include:  Testing for indicators for faecal pollution.  Turbidity  Chlorine (residual)  pH
  35. 35. Location of sampling points Representative of the different sources from which water is obtained by the public or enters the system.  Representative of the conditions at the most unfavourable sources
  36. 36. Sampling frequency in piped water system POPULATION No. OF MONTHLY SERVED SAMPLES <5000 1 5000-100,000 1/5000 population >100,000- 1/10,000 population 500,000 +10 additional samples >500,000 1/10,000 population +50 additional samples
  37. 37. Sampling methods for physicochemical analysis • Collected in clean glass stoppered bottles– WINCHESTER QUART BOTTLES. •Rinse three times with water before filling. • Stored at low temperature(40C)
  38. 38. Samples for bacteriological examination Clean sterilized bottle, 200-250 ml. Add sodium thiosulphate, if sample contains chlorine. Should not be opened before filling. Collect sample. Examine or keep in ice until analyzed. Iced sample should be analysed within 48 hrs after collection.
  39. 39. Water quality – criteria and standards I. Acceptability aspects II. Microbiological aspects III. Chemical aspects IV. Radiological aspects
  41. 41. Inorganic constituent Permissible level Reasons Treatment Turbidity 5 NTU Appearance Filtration Colour 15 TCU Appearance Filtration, Distillation, Reverse osmosis, Ozonisation
  42. 42. Inorganic constituent Permissible level Reasons Treatment Taste and odour ------ Should be acceptable Activated carbon, air stripping, oxidation, filtration Temperature ------- Should be acceptable -------
  43. 43. Inorganic constituent Permissible level Reasons Treatment Aluminium 0.2mg/l Deposition, discoloration Neurological disorders, Alzheimer’ disease Ammonia 1.5 mg/l Odour & taste Algal growth
  44. 44. Inorganic constituent Permissible level Reasons Treatment Chloride 250mg/l Taste & corrosion ----------- Hardness ---------- Scale deposition, scum formation, corrosion Removed by ion exchange, RO
  45. 45. Inorganic constituent Permissible level Reasons Treatment Hydrogen sulfide 0.05 mg/l Odour and taste Activated carbon, air stripping, oxidation, filtration Iron 0.3 mg/l Staining Oxidizing filter
  46. 46. Inorganic constituent Permissible level Reasons Treatment Manganese 0.1 mg/l staining Ion exchange, chlorination, oxidizing filter, Dissolved oxygen -------- Indirect effects -----------
  47. 47. Inorganic constituent Permissible level Reasons Treatment pH 6.5 – 8.5 Low – corrosion High-taste, soapy feel Increase pH- by soda ash Decrease pH – by citric acid Sodium 200 mg/l Taste -------
  48. 48. Inorganic constituent Permissible level Reasons Treatment Sulphate 250 mg/l Taste, corrosion RO, distillation, ion exchange Total dissolved solids 1000 mg/l Taste RO, distillation, ion exchange Zinc 3 mg/l Taste same
  49. 49. Microbiological aspects a) Bacteriological indicators : (1) Coliform organisms (2) Faecal streptococci (3) Cl. Perfringes b) Virological aspects c) Biological aspects
  50. 50. Bacteriological quality of drinking water Organisms Guideline value All water intended for drinking E. coli or thermotolerant --- must not be detectable coliform bacteria in any 100 ml of sample
  51. 51. Treated water entering the distribution system: Treated water entering the distribution system: E. coli or thermo- Must not be detectable tolerant coliform in any 100 ml sample bacteria E.Coli or thermotolerant coliform bacteria Must not be detectable in any 100 ml sample Total coliform Must not be detectable bacteria in any 100 ml sample Total coliform bacteria Must not be detectable in any 100 ml sample
  52. 52. Treated water in distribution system: Treated water in distribution system: E.coli or thermotolerant bacteria Must not be detectable in any 100 ml sample E.coli or thermo- Must not be detectable tolerant bacteria in any 100 ml sample Total coliform bacteria Must not be detectable in 100 ml sample. In case of large supplies, where sufficient samples are examined, must not be present in 95% of any samples taken throughout 12 months period.
  53. 53. Tests employed are: 1. Presumptive coliform test: Multiple tube method Membrane Filtration Technique 2. Tests for detection of faecal streptococci and Cl. Perfringes. 3. Colony count
  54. 54. VIROLOGICAL ASPECTS : Free from any viruses. Disinfection with 0.5 mg/l of free residual chlorine for 30 min contact period at a pH 8.0 is sufficient to inactivate viruses. Ozone also has strong virucidal effect.
  55. 55. CHEMICAL ASPECTS INORGANIC CHEMICALS: Constituents Recommended max limit (mg/l) Antimony 0.005 Arsenic 0.01 Barium 0.7
  56. 56. Boron 0.3 Cadmium (batteries, fertilizers) 0.003 Chromium 0.05 Copper 2 Cyanide(industrial 0.07 contamination) Fluoride (geographical area) 1.5 Lead (household plumbing system) 0.01
  57. 57. Manganese 0.5 Mercury 0.001 Molybdenum 0.07 Nickel 0.02 Nitrate 50 Nitrite 3 Selenium 0.01
  58. 58. ORGANIC CONSTITUENTS Constituents Max limit (μg/L) Carbon tetrachloride 2 Dichloromethane 20 Vinyl chloride 55 1.1-dichloroethane 30 1.2-dichloroethane 50
  59. 59. Aromatic hydrocarbon Benzene 10 Toluene 700 Xylenes 500 Ethyl benzene 300 Styrene 20 Benzolalpyrene 0.7
  60. 60. PESTICIDES MAX LIMIT(μg/L) Aldrin 0.03 Chlordane 0.2 DDT 2 2,4-D 30 Heptachlor 0.03 Hexachlorbenzene 1 Lindane 2 Methoxychlor 20 Pentachlorophenol 9
  61. 61. RADIOLOGICAL ASPECTS Should be as low as possible Proposed guideline value: Gross alpha activity – 0.1Bq/L Gross beta activity – 1.0Bq/L
  62. 62. PROGRAMMES FOR SAFE WATER •National drinking water mission : introduced in 1986, renamed as Rajiv Gandhi National drinking water mission in 1991. •Accelerated urban water supply program : initiated in 1993-94. •National rural drinking water quality monitoring and surveillance program : launched in 2006.
  63. 63. •Bharat Nirman : rural drinking water is one of the six components . •National urban renewal mission : to provide infrastructure facilities including water supply.
  64. 64. REFERENCES 1. Guidelines for drinking water quality WHO Geneva 2010;4th ed. 2. Millennium Development Goals India country report 2011. 3. Text Book of Social and Preventive Medicine by K. Park. 4. Health Policies and Programmes in India by Dr. D. K. Taneja 5. ml 6. 200607-195.pdf