A fish kill has occurred in the Tolka river in Blanchardstown, west Dublin, Inland Fisheries Ireland (IFI) have confirmed. The authority said on Monday evening that it was still quantifying the kill but estimated that it was “in the hundreds”.
The authority is “following a definite line of inquiry” regarding the cause of the fish kill, which occurred upstream of the Mill Road Bridge.
“With the river in flood it’s very difficult to determine the extent and nature of its impact, but we know we have recorded dead fish up to approximately 1km downstream,” the authority said in a statement.
Investigations are continuing on Monday, after local angling and environmental groups reported the fish kill on Friday.
The Environmental Protection Agency (EPA) said on Monday that it had been informed by members of the public over the weekend of “what appeared to be sewage” in the Tolka river in Blanchardstown.
The EPA said that Uisce Éireann were investigating the matter and that the authority had requested more information from the water utility company.
Uisce Éireann and Fingal County Council both investigated the alleged discharge of sewage at Blanchardstown but said that there were no issues with the wastewater network in the area.
Uisce Éireann noted that during periods of heavy rainfall, when sewers and pumping stations become overwhelmed, storm water overflow points “enable excess flows to be discharged into the sea, rivers or watercourses in a controlled and regulated manner.
“Stormwater discharges normally do not have a last [sic] effect on receiving waters as they are screened and highly diluted with rainfall,” Uisce Éireann said in a statement on Monday.
Michael Moore, chairman of the Tolka River Environmental Alliance, said he reported the fish kill to IFI on Friday after walking the river Tolka in Blanchardstown. Mr Moore said he had fears that the size of the kill could be significant.
Diarmaid Healy, a radiologist at Connolly Hospital in Blanchardstown, said he had reported a strong smell coming from the river to Fingal County Council last month, fearing a concentrated sewage leak.
John Whipple, a trade union organiser with People Before Profit, reported an overspill in the Tolka at Blanchardstown to the EPA on Saturday, having travelled to the site.
He described seeing “yellow-brown” coloured water gushing from a storm drain into the Tolka river.
“The smell was really overpowering ... gag-inducing,” Mr Whipple said.
He expressed worries over potential danger to wildlife in the event of a sewage spill.
IFI said various species of fish can be found in the affected area of the Tolka, including brown trout, stone loach, three-spined stickleback and minnow.
“Other species such as the critically endangered European eel, the endangered and protected Atlantic salmon, lamprey and migratory sea trout have all been recorded in the system highlighting the sensitivity and value of the river Tolka – not only in terms of biological diversity and natural heritage but also as a supporting feature in many positive initiatives at local community level,” the IFI said.
