Alternative water samples taken in Cork city compliant with manganese levels, say Uisce Éireann 

Uisce Éireann has said it did not inform the public of manganese levels almost four times the legal limit in a sample taken from Cork city’s drinking supply because other samples taken at the time might not have contained those high levels.

Manganese is a naturally occurring mineral which can, at high levels, be extremely harmful, potentially affecting brain development in children, and can also cause symptoms similar to Parkinson’s disease in adults.

The EU Drinking Water (2023) Regulations allow a maximum of 50 microgrammes of manganese per litre (µg/L), but on March 3, manganese levels of 193µg/L were recorded in a sample taken near Gardiner’s Hill.

That sample came from a water supply potentially affecting 86,738 people.

Shocking

In correspondence published by The Echo — and later described by Taoiseach Micheál Martin as “shocking” — the HSE expressed serious concern that Uisce Éireann had not informed the public.

Queried about this correspondence, Brian McCarthy, Uisce Éireann’s regional operations manager, told The Echo the water utility company had undertaken a weekly schedule involving widespread sampling across the city.

“On any given week, we sample different 25 locations around the city, and on the week of the 193(µg/L), there might have been 23, 24 samples taken, all of which are compliant, so where do you stop?

“What about the other 24 samples that were fully compliant? Are you going to tell all those people that their water is unsafe?” He said that “up to 94, 95%” of samples were in compliance on manganese limits.

“The other thing it does, it confirms our health advice as being correct, that if the water is running clear, it’s safe to drink, and if it’s discoloured you shouldn’t drink it, where we are getting non-compliances, we’re getting colour levels in the water that are discernible to the human eye,” he said.

Letter

However, in a letter dated February 14, the HSE had said that Uisce Éireann “must understand that the HSE’s health advice is not based on the subjectivity of whether water is discoloured or not, but on evidence-based manganese concentration levels in drinking water in relation to health.

“The HSE emphasises that, if consumers in affected areas are being exposed to drinking water with manganese levels above 80µg/l on an ongoing basis, then our immediate recommendation would be a ‘Do Not Consume’ notice.”

Mr McCarthy said this advice had formed the basis for Uisce Éireann’s decision to expand its water sampling programme.