Fish populations in a series of lakes which form part of the River Lee in Bedfordshire have been devastated after sewage was washed into them from nearby Luton.
The Environment Agency (EA) and Thames Water are now investigating the causes of what they describe as a 'significant' pollution incident after staff at the Luton Hoo estate became concerned at a horrendous smell emanating from the lakes at the end of February.
Tests showed a large drop in oxygen levels and further investigations showed the cause to be a blocked sewer which is being cleared by Thames Water.
Oxygen was pumped into the lakes last week in a bid to alleviate the problem, but by this stage oxygen levels had dropped to 2%, leading to the deaths of thousands of small fish, with hundreds of birds, including gulls, herons and cormorants feasting on the stricken fish.
The lakes are considered an important nursery for fish populations on the river and it's now estimated that it will take between 12 and 18 months for them to recover. Estate managers at the five-star venue are now seeking assurances that the incident will not be repeated.
Jenny Melvin from the EA said, "This is a significant sewage pollution incident which has caused the death of a large number of fish. It's distressing to see such damage to a beautiful part of our environment, which will impact on the local community and particularly anglers who enjoy fishing the lakes.
"We are still on the ground assessing the impact of this incident and ensuring that all action is taken to prevent any further risk of harm to the river. We have started an investigation into its cause."
Thames Water has not yet commented on the incident.
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