| 8.9°C Dublin

Deadly bacteria found in popular swimming spots ranked ‘excellent’ in water quality tests


Salthill beach in Galway received a Blue Flag this year

Salthill beach in Galway received a Blue Flag this year

Salthill beach in Galway received a Blue Flag this year

A deadly bacteria that can cause serious illness and death has been found in popular swimming spots ranked as excellent in annual water quality classifications.

Scientists at NUI Galway found shiga-toxigenic escherichia coli (STEC) in 57pc of samples from sea swimming areas and 78pc of lake and river bathing spots tested.

Yet STEC is not looked for in water quality checks carried out by local authorities as EU regulations do not require testing for it.

The NUI Galway team say that needs to change.

STEC is a virulent form of ecoli and can cause severe sickness, with around 30pc of cases requiring hospitalisation and 10pc of patients developing potentially life-threatening kidney failure.

Ireland has the highest incidence of the disease in the EU, with a rate 16 times higher than the EU average resulting in several hundred cases a year.

Yet all of the sea bathing areas tested in the study and found to have STEC, consistently ranked as excellent or good by EU standards.

The research was carried out under NUI Galway’s PIER Project led by Professor Dearbháile Morris and funded by the Environmental Protection Agency.

Daily Digest Newsletter

Get ahead of the day with the morning headlines at 7.30am and Fionnán Sheahan's exclusive take on the day's news every afternoon, with our free daily newsletter.

This field is required

Prof Morris noted the most recent bathing water quality reports showed 96pc of officially designated bathing waters met the minimum required standard.

“However, our research has revealed the presence of organisms of public health concern in waters designated as of excellent quality,” she said.

“These findings highlight the need to consider revision of current EU bathing water quality monitoring criteria.”

PIER researchers used 111 water samples of 30 litres each from 50 locations in Galway, Cork and Fingal.

They have not revealed the specific locations, saying the focus of the research was to establish whether STEC was present in Irish waters rather than rank individual beaches.

Of 27 lake and river samples, 21 tested positive, as did 48 of the 84 seawater samples. Water quality often drops after heavy rain, but the PIER team found STEC present regardless of weather conditions.

STEC is commonly found in the intestines of cattle and sheep and the suspected transmission route to humans is usually through undercooked food or faecal matter entering water supplies.

The PIER team found that in about half of cases, there is no obvious transmission source, but investigations were limited to drinking water and food, while bathing waters were not generally considered.

The most serious complication of STEC is haemolytic uraemic syndrome (HUS) which can cause renal failure and risk of death.

“Those who survive may require long-term renal dialysis or a kidney transplant,” the study warns. Children under five are most at risk.

Calls have been growing for more thorough testing of the country’s bathing waters as the popularity of water-based activities and year-round swimming increases.

Testing of officially designated bathing areas is only obliged to be carried out from June to September and only for the organisms set down in the EU regulations.

The Environmental Protection Agency is among those backing calls for greater testing.

To coincide with the publication of their research, the PIER team have launched a survey to examine how people use their coastal and inland waters. They are asking members of the public to help by answering the questions at www.nuigalway.ie/bluespaces.

Most Watched