Purpose of Program for Monitoring Hanoi Drinking Water

Community Service Project

  • Provide information to the local and international community in Hanoi on drinking water safety.
  • Determine Arsenic levels in Hanoi water supply
  • Other parameters tested: nitrate, manganese, iron, hardness, total coliform, fecal coliform and free chlorine.
  • Sampling sites: Households in the city nearby 13 main water supply treatment plants (WSPs) and 4 smaller water treatment stations

Sampling Period

  • 27 rounds from May 2009 to Apr 2016, sampled quarterly

Water Supply Plants in Hanoi

methodology-1Water Supply Plants

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Field Program

  • 32-35 water samples taken on each round
  • Sample location description
  • GPS location
  • Field parameters tested
        Free chlorine
        Turbidity
        pH
        Temperature

Sample Handling

  • Sample Collection
    • 250 ml PE bottles are filled with water samples and stored and cooled by ice in a sealed container
    • Samples delivered to the analytical laboratory within 8 hours
  • Sample Acidification
    • Samples for metallic parameters analysis are acidified with 3ml HNO3 solution

Laboratory Analysis

  • Laboratory for Arsenic, other metals, and nitrate analysis:
    • From May 2009 to December 2010: Institute Of Geological Sciences. Add: 84 Chua Lang Street, Dong Da, Hanoi.
    • From December 2010 to Present: Department of Environmental Quality Analysis (DEQA) of Institute of Environmental Technology (IET) – Vietnam Academy of Science and Technology (VAST). Arsenic concentrations were measured by Inductively Coupled Plasma – Mass Spectrometry (ICP-MS)

Testing Quality Assurance

  • Chain of Custody:
      At the Institute a “Chain of Custody/Analytical Request Form” is filled in and signed by both the DS-Intl staff and the Lab staff
  • Duplicates:
      Each round: duplicate samples account for 10% of total samples
  • Blanks:
      One distilled water and three bottled water brands samples tested
  • Matrix spikes for coliforms:
      Samples taken from the West Lake

Water Quality Standards

Primary Water Quality Standards (for drinking water)
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Sampling Locations

  • Sampling site selection criteria follows procedures:
      Tap water at households using treated water
      The closest residential place from the targeted water plant (normally not further than 1km)
      A few additional locations were selected to provide a broader coverage in the city
  • Samples from the chosen locations were consistently sampled each quarter over the study period

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Arsenic Results

Arsenic

  • Odorless and tasteless.
  • Enters drinking water supplies from agricultural and industrial practices or natural deposits in the earth
  • Arsenic has been linked to cancer of the bladder, lungs, skin, kidney, nasal passages, liver, and prostate (EPA, USA)
  • National technical regulation on drinking water quality (QCVN 01:2009/BYT) and WHO standards allow maximum contaminant level (MCL) of 10 ppb for Arsenic

Results

  • During Seven years of the study, 15 sampling sites (43% of 35 total sites) have been found to have average arsenic levels over the MCL of 10 ppb (µg/L)
  • Overall, average arsenic levels at these 15 sampling sites was 19.63 ppb
  • Of those 15 locations, the site with the lowest average arsenic level was 12.50 ppb, and the site with the highest was 28.24 ppb

Elevated Arsenic Locations

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Arsenic Results

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