Illegal interconnection of drinking

water and irrigation water system (Case study)

Workshop on Water and Climate Adaptation Workshop on Water and Climate Adaptation (Amsterdam, 1–2 July 2008)(Amsterdam, 1–2 July 2008)

Martina BehanováPublic Health Authority of Slovak Republic

Dep.of environmental health

Involved stakeholders

• Regional authority of public health in Trnava

• Water company „TAVOS“

• Municipality of Jaslovské Bohunice

Step by step

• 16.7.2007 phone call to the PHA from citizens from Jaslovske Bohunice about suspicion on drinking water quality causing gastric problems

• 16.7.2007 PHA analysed 2 samples of drinking water from the blocks of flats where affected citizens lived

EARLY DETECTION: • 17.,18.7. laboratory confirmation of microbiological,

biological, chemical contamination start of epidemiological investigation

Step by step

QUICK RESPONSE

• 19.7 a ban of drinking water usage from public water supply

• Active investigation for cases in Jaslovske Bohunice in close cooperation with local GPs and municipality

• The contamination of drinking water was confirmed also by laboratory analysis provided by TAVOS

• Water company made checks along the whole distribution system in Jaslovske Bohunice and ensured emergency tanks of water for affected households

Step by step

Samples were taken from 4 places in Jaslovske Bohunice:

● block of flats

● municipality office

● amphitheatre

● fastfood kiosk

Parameter JB Municipality

JB Blocks of flats,No.420,4th

floor

JB Amphitheater,No

.420 JB,fastfood

E.coli 0 150 150 32

Coliform bacteria 0 1800 2000 65

Enterococci 0 120 130 30

Colony count 37ºC 5 146 134 50

Abioseston 5 40 40 3

Flagellates colourless 0 80 20 0

Dead organism 0 120 280 0

Living organism 0 680 1120 0

Fe and Mn bacteriae 0 5 5 0

Filamentous bacteriae 0 0 0 0

Microscopic micromycetes 0 20 0 0

Ammonium LOD 0,66 0,51 LOD

Chemical oxygene demand 0,74 1,94 1,98 0,54

Nitrites LOQ 0,166 0,157 LOD

Nitrates 9,76 6,21 6,4 10,02

Colour 0 30 20 0

Conductivity 69,83 70,84 70,84 68,83

pH 7,76 8,08 8,14 8

Turbidity 2,43 7,65 8,59 1,85

Odour without odour 2 2,5 without odour

Iron LOQ 0,23 0,282 LOQ

Manganese 0,016 0,04 0,038 0,008

Measures taken by water company

• Laboratory analysis from 17.7., 18.7. showed biological contamination and zero level of chlorine in samples taken near the block of flats

• Flush of the whole distribution system + chlorination was done

• Samples taken on 19.7 and 23.7 were NEGATIVE

Results of epidemiology investigation

Outbreak in J.Bohunice, 2007

4

15 13

26

2017

14

410

1 105

1015202530

12.7

.200

7

13.7

.200

7

14.7

.200

7

15.7

.200

7

16.7

.200

7

17.7

.200

7

18.7

.200

7

19.7

.200

7

20.7

.200

7

21.7

.200

7

22.7

.200

7

date of first symptoms

nu

mb

er

of

ca

se

s

Number of cases

Outbreak summary

• Duration 12.7. – 22.7.2007

• Number of cases: 125 (1500 exposed people, attack rate 8,3%)

• Place: Jaslovske Bohunice

• Vector of disease: Drinking water from public water supply

• Etiology: not confirmed (according to microbiological cultivation of contaminated water, it is supposed to be infectious of E.coli (EPEC) or other coliforms or Entamoeba coli)

Interesting findings

• Comprehensive investigation taken by TAVOS and municipality testified, that the epidemic outbreak occurred due to illegal interconnection of irregation water with drinking water from public supply

• It is suspected that interconnection of systems was made in a garden area near the block of flats

• PHA in cooperation with a water company informed the police and pressed charges against anonymous for the public danger

Lessons learned

• Importance of public awareness and early detection system

• Importance of well managed surveillance system of water-borne diseases

• Close cooperation of water company and local authorities (public health, municipality)