COST ACTION 920

Inventory of QMRA Studies in Europe

Pathogen

Cryptosporidium parvum

Country or region

Ireland

Transmission route

 From

Public drinking water system

To

Specific product(s)

End-point(s)

Bibliographic reference

Coady MC, Cryptosporidium parvum in Dublin’s Drinking Water – Towards a Qualitative Risk Assessment. 2003.

Abstract

The objective of this study was to assess the risk of contracting cryptosporidiosis from Dublin’s public drinking water system. This was done using the technique of qualitative risk assessment. A quantitative risk assessment was not attempted because of the extensive amount of statistical data which would be required and which is not yet being collected by Dublin City Council.

 In the study, an extensive review of the national and international literature was carried out. The review showed that the amount of published papers regarding Cryptosporidium and cryptosporidiosis while extensive internationally, is very limited in Ireland; specifically, only one study was found which related to this pathogen in Dublin’s drinking water system.

 A detailed model of Dublin’s catchment area, water treatment, and water supply network was constructed; the model covered: upper catchment area (rivers and underground sources, etc.), lakes and reservoirs, treatment plants, and pipeline systems. Interviews were undertaken with officials in Dublin City Council, and onsite visits were made to the city’s reservoirs and water treatment plants. In addition, data on oocyst monitoring results were analysed and compared with data provided by Cork City Council.

 The results show that the risk of contracting cryptosporidiosis from Dublin’s drinking water is very low. This is based on recent historical monitoring data. However, the potential risk to consumers will require much more information on catchment areas utilisation, geology, runoff, etc. than is currently collected. The uncertainties which relate to the understanding of cryptosporidium itself are also a limiting factor. Combined, these uncertainties make reliable assessments of risk very difficult. As a result it can be concluded that at this stage of development of the subject, a full quantitative risk assessment is not really possible. Therefore, qualitative risk assessment – as undertaken here - is the more sensible option at this stage. 

The demographic variability in risk throughout the consuming population was also analysed. New data required to accurately assess the risk to subgroups of the population (the very young, the old, and the immunocompromised) were set out.

 A number of detailed recommendations are made regarding new data that needs to be complied. In addition, the study suggested the need for a Dublin Catchment Area Authority to coordinate the work of the various agencies and interests that have an impact on the supply of clean, safe, drinking water to Dublin city.

Status

Completed 2003.

Availability

Available through: Library Services, Dublin Institute of Technology, Cathal Brugha Street, Dublin 1, Ireland

Institute

Dublin Institute of Technology, Cathal Brugha Street, Dublin 1, Ireland.

Contact person

M C Coady, 
98 Route de Montsoreau, 
49400 Saumur, France.

Email : mary@chateaudebeaulieu.fr

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