Drinking Water Quality and the Geospatial Distribution of Notified Gastro-Intestinal Infections

GRILC, Eva; GALE, Ivanka; VERŠIC, Aleš; ŽAGAR, Tina; SOCAN, Maja

Supply zones could not be geolocated as polygons; instead, the geographical coordinates of the sampling points were used in the presented analysis. Some records in the drinking-water supply surveillance (monitoring) sample point dataset had wrong coordinates of the surveillance location or sampling point. Most of these discrepancies could be solved manually. Unresolved cases were excluded from the analysis. Geolocating the supply zones could not be implemented fully. For the present analysis, the geographical coordinates of the sampling points were used. In the last step of data preparation, both AGI cases and supply zones were attributed to the settlements. The data on the case level was analysed, and relative risks by the size of the drinking water supply zones were calculated for users who were supplied with E.coli contaminated water. The assumption was made that persons diagnosed with AGI were drinking water from the supply zone attributed to the same settlement. For each supply zone, the data on the results of the monitoring of drinking water quality and the total number of users were available.