Threat to drinking water

HEAVY rainfall all this year is resulting in contamination of drinking water in some areas, especially those served by private supplies and group schemes.

The risk of getting an E.coli bug from animal and human waste is particularly high in untreated water from wells and in supplies where treatment is not working properly.

More than 80% of our drinking water originates from surface water, so the risk of contaminants being washed into sources is obvious. The Health Service Executive has reported a 200% increase in the number of E.coli infections (VTEC strain) between January and June of this year, compared to the same period in 2011.

Some of the increase in reported incidents may be due to better laboratory testing, but exceptional rainfall is a key factor, according to the HSE. The strain of E.Coli can cause infection and a mild illness, if swallowed. Most people recover completely, but in about 5% to 8% of cases the infection causes a life-threatening complication.

The young are very vulnerable and 56% of infections were in children under the age of five years. A multi-agency group has been set up by the HSE to look at ways of preventing water contamination.

The issue is highlighted in the latest issue of Rural Water News, magazine of the group water scheme sector, which calls for action to deal with the sources of faecal contaminants and stresses the need for effective treatment systems for raw water following very heavy rain.

About 170,000 households get their water from thousands of group schemes. The EPA drinking water report 2010 shows water quality in private schemes is generally inferior to that in public group schemes and local authority schemes.

Smaller schemes have a higher rate of non-compliance with EU standards and almost 12% of private group schemes are affected by ‘unacceptably high’ levels of E.coli, says the EPA report.

A top priority is to ensure treatment facilities are capable of coping with raw water fluctuations, such as occur after heavy rainfall. The need for having responsible people properly trained in measuring rainfall and applying the necessary dose of disinfection to raw water is also highlighted. Raw water alarms and more effective water treatment are also suggested.

And, while we might have thought this year as the worst possible in regard to rainfall, even worse could be in store if predictions regarding climate change are correct. The clock is ticking.

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