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Public Water Supply Distribution Systems Assessing and Reducing Risks: First Report (2005) / Chapter Skim
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5 Lower Priority Issues
Pages 24-29

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From page 24...
... Corrosion in distribution systems, as well as household plumbing, is a complex process still not adequately understood despite much research into the causes. A number of relevant water quality parameters such as disinfectant residual, redox potential, and pH are affected by water age, and these are believed to play an important role in the corrosion of pipe materials and the release of iron, copper, and lead from pipe scales, especially in low alkalinity waters.
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From page 25...
... Numerous papers have focused on the impact of nitrate nitrogen (nitrate plus nitrite) in drinking waters (Sandor et al., 2001; Gulis et al., 2002; Kumar et al., 2002; De Roos et al., 2003; Coss et al., 2004; Fewtrell, 2004)
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From page 26...
... as well as some ethnic groups may more susceptible to adverse health effects as a result of elevated nitrate concentrations in drinking waters (Bitton, 1994; De Roos et al., 2003)
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From page 27...
... Most known substances leaching to water from materials in the distribution system do not appear to pose a public health threat due the fact they are non-toxic, present only at trace levels, or are in a form unlikely to cause health problems. Taste and odor complaints are possible, however (see Choi et al., 1994, and Khiari et al., 2002, for examples)
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From page 28...
... For new materials, the NSF establishes levels of allowable contaminant leaching through ANSI/NSF Standard 61. It should be noted that ANSI/NSF Standard 61, which establishes minimum health effect requirements for chemical contaminants and impurities, does not establish performance, taste and odor, or microbial growth support requirements for distribution system components.
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From page 29...
... If the material is loosely attached to the pipe wall, such as some aluminum precipitates, hydraulic surges can result in substantial increases in the turbidity of tap water. Treatment of water to avoid excessive post-precipitation thus is an important asset management issue.
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Key Terms

  • drinking water
  • nitrate nitrogen
  • lower priority
  • drinking waters
  • water quality

  • health impacts
  • microbial growth
  • growth support
  • pipe materials
  • low alkalinity

  • health effect
  • pipe scales
  • alkalinity waters
  • cement materials
  • plus nitrite

  • nitrate plus
  • disinfectant residual
  • organic chemicals
  • low priority
  • health risk

  • impacts associated
  • support requirements
  • potential health
  • plastic pipe
  • organic matter

  • infants below
  • control strategies
  • lesser effects
  • priority concerns
  • effect requirements


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