For the second consecutive August, a warning has been issued not to drink water in Sligo town because of E.coli contamination.
A warning to boil all water before use in the town was issued by environmental health officers from the North Western Health Board. This followed the finding of E.coli bacteria in two consecutive samples of water last Friday.
The E.coli discovered in the water is not the same as the potentially fatal E.coli O157 bug, which can be contracted from eating uncooked meat or from drinking unpasteurised milk. But it does indicate pollution by faecal matter and could represent a serious public health hazard.
E.coli contamination more commonly occurs in small, rural water supplies which have ineffective or no disinfection. Its occurrence in a large urban supply, such as Sligo's, is very rare.
The cause of this contamination had not been established last night. E.coli presence is usually due to human or animal (notably livestock) faecal wastes. The bacterium frequently derives from animal manure, which can be washed into a water supply during heavy rain.
Environmental health officers carry out regular water-sampling for Sligo Corporation on an agency basis. With the positive identification of the microbe, they notified the local authority of the test results and issued a "notice to boil" recommendation to all food premises.
Food outlets in the town are now selling bottled water instead of providing tap water to customers, and householders have been boiling all water before consumption.
Last August a similar notice was issued following a finding of E.coli in the water. Residents were unable to use the water unboiled for several weeks.
Last June E.coli was found in the water system which supplied St Ita's Hospital in Portrane, Co Dublin. A year earlier residents in Bray and in the Connemara Gaeltacht discovered their water had been contaminated by E.coli.
The poor quality of many Irish drinking-water supplies was highlighted in a survey by the Environmental Protection Agency last year. The survey showed that just 58 per cent of rural group water schemes reached acceptable EU quality standards, compared with 92 per cent of public water schemes.
In an effort to improve rural water quality, the Minister for the Environment announced new regulations which meant deficient group water schemes had to produce an action programme to improve water quality as soon as practicable.
The Government has committed £420 million to rural water schemes over seven years. A total of £33 million was allocated last year.