Tests on a stretch of water in a popular High Wycombe park have revealed that it is safe after fears were raised last week that there could be a dangerous toxin in it.
Bloom and scum forming blue-green algae can produce toxins which can kill wild animals, farm livestock and domestic pets.
However, Wycombe District Council has now confirmed that samples taken by the Environment Agency (EA) from the Dyke late last week do not contain the potentially dangerous blue-green algae as originally suspected.
Instead, the odd colour of the water has been caused by calcium carbonate, a natural mineral that will not harm wildlife.
The EA's report says that limestone and chalk rocks are made of calcium carbonate and when rainwater seeps down into the rocks, some of the calcium carbonate dissolves into the water.
The calcium carbonate rich water then comes out of springs into rivers and lakes.
Usually the calcium carbonate stays dissolved but sometimes - especially when there has been little rainfall, the calcium carbonate turns the water "milky white".
Members of wildlife hospital Tiggywinkles in Haddenham were called out to test the waters after a dead swan was discovered in the lake of Wycombe Abbey School, which links to the Dyke.
It was later revealed that samples taken by the EA did not contain the blue-green algae as originally suspected.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here