Risk assessment of nitrate in drinking water

This is the main page of nitrate risk assessment conducted in INTARESE WP3.4. The analytica file can be uploaded here: File:Nitrate.ANA

Scope

Purpose

To investigate the effects of nitrate contaminated drinking water.

Boundaries

• European countries in selected regions:
  • Finland
  • Romania
  • Spain
  • UK
• Infants < 6 months of age
• Exposure to nitrate via baby food formula mixed with drinking water
• Effects: infant methemoglobinemia

Scenarios

• BAU (business-as-usual)

For the first pass it was deemed appropriate to carry out a diagnostic assessment i.e. to estimate the scale of the health impacts under present conditions, which in this case make use of 2001 as the baseline year. It was recognised that the causal diagram should be constructed in such a way that the introduction of policy scenarios is possible, since this is intended for the second pass of the assessment. The introduction of such potential policy scenarios would allow the diagnostic assessment to be transformed into a prognostic assessment i.e. a causal diagram which allows the estimation the likely consequences of different policy options, primarly as a basis for choosing between them.

Participants

• Researchers at KTL
• Researcher at Imperial College London
• Researchers at London School of Hygiene & Tropical Medicine
• Researchers at Municipal Institute of Medical Research Foundation

Definition

Causal diagram

Detailed documentation of the design, elaboration and construction of the causal diagram to be used in this assessment is given in this article. The final draft is presented in figure 1. The working Analytica version of the nitrate model File:Nitrate.ANA.

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  Figure 1 - Causal diagram for assessment of the impacts of exposure to nitrate due to MetHg

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  Figure 2 - Analytica model of nitrate risk assessment

Decision variables

• Water source (population using public/private water supplies)

Indicators

• Health risk estimates for infant MetHg
• Excess cases of iMetHg
• Total ingestion of nitrates in drinking water by infacts < 6 months

Other variables

• Concentration of nitrate in drinking water from public supply
• Concentration of nitrate in drinking water from private supply
• Exposure of infants < 6 months to water from private supply
• Infection status of infants < 6 months
• Exposure response function for nitrate and iMetHg

Modules

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  Figure 3 - Sources

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  Figure 4 - Exposure

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  Figure 5 Dose response

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  Figure 6 - Health effects