IRELAND'S ENVIRONMENTAL Protection Agency (EPA) this week threatened to prosecute Galway City Council after nearly 200 people were diagnosed with cryptosporidium poisoning.
The council is responsible for providing drinking water to people across the west coast county of Galway.
The first cases of cryptosporidium were diagnosed in mid-March, forcing thousands of people to boil their water before drinking it.
Just last month the EPA gained powers to prosecute suppliers that provide water that is unfit for human consumption or that allow pollutants to degrade river water quality. A spokeswoman said that it fireserved the rightfl to take action against Galway City Council.
Cryptosporidium is a bacterial disease that causes diarrhoea and vomiting. The organism lives in human or animal hosts and lays eggs called oocysts, which the host excretes. Oocysts can survive for long periods in water until they are ingested by a new host where they hatch and repeat the cycle.
The outbreak has been blamed on heavy rainfall during January and February that led to sewage and livestock slurry being discharged into the River Clare, the source of most of the county's raw water.
According to the EPA an old treatment plant at Terrylands has been identified as the principal route by which the cryptosporidium entered the water supplies.
Galway City Council plans to take the Terrylands plant out of service in early summer. It claims it cannot shut the plant down sooner because it needs to put extra treatment capacity in place at another plant in order to prevent a supply shortfall.
The Terrylands plant will be upgraded with improved -ltration systems.
In a statement Galway City Council defended its past performance: fiSince 1999, monthly [monitoring] results for cryptosporidium indicate that at no time, prior to the current outbreak, did the levels exceed the UK guideline value [of one egg per 10l of treated water]fl.
Unlike the UK, the Republic of Ireland has no legislation requiring water to be treated to eliminate cryptosporidium.
But the EPA is demanding that all local authority water suppliers carry out risk assessments and continuous monitoring on their abstraction sources; that suitable water treatment measures are put in place to ensure water is -t for consumption; and that water sources are not contaminated.
A survey of surface water abstraction sources in 2005 suggests that 20% of the Republic of Ireland's raw water could be contaminated with cryptosporidium.
European Union legislation requiring treatment against cryptosporidium is to be introduced in 2010 as an addition to the Drinking Water Directive.
Cryptosporidium is typically eliminated using membrane -ltration or ultraviolet treatment.
The UK cryptosporidium regulations are to be tightened up this year, making ultraviolet a standard treatment.