Scottish Water has admitted killing hundreds of salmon and trout by pouring a toxic chemical into the River Eden and suffocating the fish.
The quango was fined £6,700 after pouring around 400 litres of jelly-like polymer Zetag into the river near Cupar.
Dundee Sheriff Court was told a large number of wild salmon, brown trout and sea trout died within hours as the chemical sucked the oxygen out of the river.
Around 500 dead fish were found floating on the surface of the river, but the court was told the number of deaths may have been far higher with many more dead fish under the congealed surface.
The court was told the spillage took place when a forklift truck driver accidentally punctured a 1,000 litre container of Zetag, used in the water purification process.
Staff unaware of environmental impact
Fiscal depute Joe Stewart told the court staff had not realised the material had been washed into the river or the devastating impact it would have on the wildlife.
He said: “Around 400 litres leaked out before they turned the container over.
“They were unaware it was harmful to aquatic life. It was hosed into the nearest surface drains.
“They mistakenly thought it went to the waste water treatment works but it went directly into the River Eden.
“It entered the river in at least three locations.”
No-one at the plant, including the team leader, informed anyone of the spill and SEPA only became aware when walkers spotted dead fish floating on the water.
Mr Stewart said: “SEPA attended the following morning and observed the container still dripping onto the ground. They could see Zetag in the vegetation.
“They could see clumps of chemical in the river and floating downstream.
“There were a large number of dead fish visible in the river .
“Around 500 dead fish were seen downstream; brown trout were the majority, but also sea trout and salmon.
“Most were within a kilometre of the works, but some were as far as three kilometres.
“There were almost certainly many more on the river bed that were not visible. They had suffocated.”
Fish stocks harmed for years
He said Scottish Water’s initial decision to describe the spill as “minor” was “misleading” when it was a serious incident which would harm the fish stocks for years to come.
“A fish kill of that magnitude impacts salmon and trout number for four to five years. It has caused serious financial consequences for the Eden Angling Association.”
He said the association’s membership had fallen by a quarter within a year of the October 2018 incident and ticket sales had fallen by almost a third.
“They had been forced to dip into their cash reserves as a consequence.”
Solicitor Steve Matthew, defending, said: “It is quite a thick material which turns to jelly when it makes contact with water. It attracts the debris in the water.
“They didn’t realise the Zetag had made it into the river. Fish were killed and we regret that it happened.
“We made immediate changes and spent £200,000 to address the problem and make sure it won’t happen again.”
Sheriff Alison Michie said: “I am concerned about Scottish Water’s lack of awareness and training. None of them were aware of the impact the spillage would have.
“The initial occurrence was nothing more than human error.
“Thereafter what has occurred I would consider could have been avoided or at least mitigated had Scottish Water put in place suitable training for staff.
“I do consider it a serious incident. I take into account the failure to take into account the severity of the incident.
“There was no training in place even 13 months after this incident.”
The company, which is owned by the Scottish Government, admitted carrying on a controlled activity in a manner liable to cause pollution of the water environment.
