Blooms of blue green algae are still polluting two lakes in Lincoln, almost two months since they first developed.
Millennium Lake in North Hykeham first developed the algae, which turned the water a bulbous green colour, in late July. Shortly after, Hartsholme Lakes in Lincoln also had the same problem.
North Kesteven District Council cordoned off the area and told residents that this could be toxic for pets, urging people to stay away.
This is still the case seven weeks on, with a fresh warning issued by the council that the warm weather is causing this.
David Steels, head of environment and public protection at NKDC, said: “Bluegreen algae is present all the time in many bodies of water, however it is factors such as prolonged calm and warm weather which cause it to form in bloom proportions as we’ve seen at Millennium Lake.
“Our latest checks at the lake have found pockets of blue green algae bloom still present, due to the long period of warm weather we’ve seen.
“This means it’s still vital that pets do not go in the water or near the shoreline, as types of algae are toxic to them.
“It’s crucial too that nobody swims in the lake, as blue green algae can also cause illness in humans.
The toxic algae was also found at Hartsholme Park in August, and the City of Lincoln Council said the water is still contaminated.
A spokesperson for CoLC said: “We have not noted another bloom since the dispersal of the first.
“However, as the algae is always present but is only visible when conditions are correct for a bloom, we will be keeping signage in place to that effect.
“It is a sensible precaution not to allow dogs to enter the waters, this is also beneficial to other wildlife.”