Tap Water A Public Health Asset

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Tap Water A Public Health Asset

• Professor Jeni Colbourne
• Chief Inspector of Drinking Water

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Outline

• Tap Water and Health Historical Context
• Tap Water Quality 1990 2003 A success story?
• Is there more to be done? If so why and what?

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Annual Report of the Medical Officer of the Privy
Council and Local Government Board presented to
the Houses of Parliament1874

• Whilst regarding filth as the deadliest of
  our present removable causes of disease I am far
  from regarding it as the only evil influence
  against which Sanitary Authorities have to
  contend and, however admirable may be the local
  arrangements of sewerage, scavenage and water
  supply.other preventative arrangements are
  needed and the utmost vigilance should be used
  everywhere..to prevent the scattering of the
  seeds of contagion.
• The foetid gases hurt only by instant
  action and in direct proportion of its palpable
  and ponderable dose, but it is the wider
  possibilities of mischief which reside in filth,
  the morbific ferments or contagia which are at
  the heart of the problem. These are not only
  gaseous but have their essence in certain solid
  elements which the microscope discovers in them,
  organisms which by virtue of their vitality are
  indefinitely self mulitplying.

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Watershed Conference The Future of Water
Quality in Europe1989

• What might be the effect of the present
  climate of setting quality standards instead of
  defining good practice and establishing quality
  control procedures?
• It can be argued that the dramatic demise of
  the babyfood company, whose products caused an
  outbreak of salmonellosis in young babies when
  microbiological quality control was reduced by
  pressure to improve economic performance, is a
  situation that could be repeated on a far wider
  scale by a water utility Colbourne 1989

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Where does todays tap water come from?Water
Industry in England and Wales 2003
1 Anglian Water Services Limited2 Bournemouth
and West Hampshire Water Plc3 Bristol Water
Plc4 Cambridge Water Company5 Cholderton and
District Water Company Limited6 Dee Valley Water
Plc7 Dwr Cymru Cyfyngedig8 Essex and Suffolk
Water Plc (part of Northumbrian Water Limited)9
Folkestone and Dover Water Services Limited10
Hartlepool Water Plc (part of Anglian Water
Group)11 Mid Kent Water Plc12 Northumbrian
Water Limited13 Portsmouth Water Plc14 Severn
Trent Water Limited15 South East Water Plc16
South Staffordshire Water Plc17 South West Water
Limited18 Southern Water Limited19 Sutton and
East Surrey Water Plc20 Tendring Hundred Water
Services Limited21 Thames Water Utilities
Limited22 Three Valleys Water Plc23 United
Utilities24 Wessex Water Services Limited25
Yorkshire Water Services Limited Inset
Appointment26 Albion Water Limited
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The Tap Water Industry in England and Wales2003

• 26 Water Companies
• Supply 15,999 Ml/d
• 53.3 million people
• 1,303 treatment works
• 4,669 service reservoirs
• 331,338 km of water mains
• 2,249 water supply zones
• 2,848,723 regulatory samples

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The Legal Framework

• EC Directive
• 98/83 on the quality of water intended for human
  consumption
• England Wales Primary Legislation
• Water Industry Act 1991 (Water Act 2003)
• England Wales Secondary Legislation
• Water Supply (Water Quality) Regulations 2000
• (as amended)
• Water Supply (Water Quality) Regulations 2001
• Water Undertakers (Information) Direction 2004

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Drinking Water Inspectorate

• Independent Drinking Water Quality Regulator
• Established in January 1990(38 posts - 23
  professionally qualified staff)
• Funded by the Water Directorate, Department for
  Environment, Food and Rural Affairs
• Technical advisors to both (DEFRA) and National
  Assembly for Wales (NAW)

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DWI role - surveillance and verification

• Technical audit (water supply safety checks)
• Investigation of incidents (prosecution powers)
• Public reporting on drinking water quality
• Investigation of consumer complaints
• Authorised departures, undertakings and
  programmes of work (enforcement powers)
• Committee on Products and Processes
• Research

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Water Supply (Water Quality) Regulations

• The Regulations set out inter alia
• delineation of water supply zones
• the standards to be met
• the self monitoring regime required to be carried
  out by the water companies
• at treatment works, service reservoirs, supply
  points and consumers taps
• the standards to be met (98/83/EC plus National)
• investigation of failures
• requirements for analytical systems
• treatment requirements
• requirement for public availability of all
  results

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How effective was the 1989 regime of surveillance
and verification?Number of tests not meeting the
standards 1992 - 2003

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Water Company X Total number of tests not
meeting the 1989 standards 1992 - 2003
13
Company XColiform failures at Works and Service
Reservoirs 1992-2003
14
Water Company XFailures to meet the revised lead
standard (25 µg/l) 1994 -2003
15
Water Company XFailures for iron and
manganese1995-2003
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Consumer view of compliance

• 99.88 compliant waterbut not at my tap?
• You cant tell me this muck is safe?

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How do we safeguard tap water safety in the
future?

• Different reporting against new drinking water
  regulations standards to address consumer
  concerns
• Focus on what makes tap water safe?

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WHO 3rd Guidelines Sept 2004

• Safe drinking-water is available to millions,
  but improvements are needed
• Not just a developing world issue?
• outbreak of cryptosporidiosis in Milwaukee (USA)
  that affected 400,000 people
• and E coli O157 and Campylobacter outbreak in
  Walkerton (Canada) that infected more than 2000
  and killed seven
• Natural not synthetic chemical hazards have
  proved of greatest significance (arsenic,
  fluoride, uranium)

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Meeting the new EU standards
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Meeting the revised EU standards
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WHO view on why we need to review our approach

• In all countries waterborne illness still occurs
• Outbreaks show us that we cannot solely rely on
  water treatment indicators
• We dont know about sporadic cases of water
  related illness
• End-point testing is too-little-too-late

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Risk Factors

• Outbreak Causes not prevented by end point
  testing
• inadequate water treatment 54
• untreated groundwater 23
• distribution deficiencies 12
• untreated surface water 8

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1999 Cryptosporidium Regulations Monitoring
results
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Cryptosporidium RegulationsWater Supply (Water
Quality) Regulations 2000

• Require continuous monitoring of at least 40
  litres per hour of treated water at treatment
  works identified as at significant risk
• Set a treatment standard of an average of less
  than one oocyst per 10 litres of treated water

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Results of risk assessment

• Water treatment works in England and Wales 1481
• Identified as at significant risk 332
• Works treating surface water 158
• Works treating groundwater 174

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Impact of Regulations

• 103 small water treatment works abandoned or
  taken out of use because of risk
• Membranes installed at 51water treatment works
• Treatment improvements at many other sites
• Concentration on good treatment
• Coagulation, filtration, turbidity

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WHO Guidelines

• WHO Third Edition of the Guidelines on Drinking
  Water Quality launched on 21 September 2004
• Place considerable emphasis on Drinking Water
  Safety Plans (DWSP)
• DWI sees DWSP as the way forward for the
  Cryptosporidium Regulations
• Elements of DWSP already in place

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Drinking Water Safety Plans

• Management of drinking water quality in a
  holistic, systematic fashion from source to tap
• Assessment of risk
• Appropriate barriers
• Validation (operational monitoring)
• Verification (audit and end point testing)

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DWSP and the Cryptosporidium Regulations

• Risk assessments carried out for all water
  treatment works all microbes
• Attention to barriers
• Treatment validated by monitoring?
• Challenge to treatment up front critical
  control point e.g. raw water quality

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Way forward?

• Change Regulations / Guidance to require a
  validated Drinking Water Safety Plan for each
  water treatment works
• Cryptosporidium will remain a major risk factor
• DWSP will require appropriate barriers (proof
  that treatment is robust and always under
  control)
• Some monitoring for Cryptosporidium will be
  required for verification and validation but
  emphasis will move away from end-point monitoring
• Provide due diligence
• Retain treatment standard?
• Publish proposals by the end of 2004

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Further information

• www.dwi.gov.uk