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Pathogens in water: value and limits of correlation with microbial indicators
1Centre INRS-Institut Armand-Frappier, Institut national de la recherche scientifique, 531 boulevard des Prairies, Laval, Québec, Canada H7V 1B7. pierre.payment@iaf.inrs.ca
Ground Water
|May 19, 2010
Summary
Microbial indicators in water can suggest pathogen presence, but direct prediction is often unreliable due to environmental factors. Absence in groundwater indicates safety, while detection raises risk concerns.
Area of Science:
- Environmental microbiology
- Water quality assessment
- Public health
Background:
- Sewage is a primary source of fecal contamination in water bodies.
- Understanding pathogen-indicator relationships is crucial for water safety.
- Microbial indicators are used to assess water contamination risks.
Purpose of the Study:
- To evaluate the predictive value of microbial indicators for enteric pathogens in various water types.
- To analyze the correlation between pathogens and indicators in sewage, surface water, and groundwater.
- To determine the limitations of microbial indicators in water quality monitoring.
Main Methods:
- Analysis of three datasets: sewage, surface water, and groundwater with varying pathogen and indicator concentrations.
- Statistical analysis, including logistic regression for surface water data.
- Comparison of pathogen and indicator behavior in different aquatic environments.
Main Results:
- No reliable mathematical correlation between indicators and pathogens was found in sewage.
- Logistic regression showed some predictability of pathogen occurrence (not counts) in surface water.
- In groundwater, absence of indicators suggests low pathogen risk, while detection increases probability.
Conclusions:
- Microbial indicators have limitations in precisely predicting pathogen presence and concentration.
- Environmental factors like dilution and inactivation affect indicator-pathogen correlations.
- Indicators are valuable for risk assessment, especially in groundwater, but do not guarantee pathogen absence.
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