Algae warning at Roath Park lake in Cardiff
People are being warned not to go on to a popular lake in Cardiff following the discovery of potentially toxic algae.
Cardiff council said boating activities had been suspended on Roath Park lake and it has warned people to keep their pets out of the water.
Water samples are being analysed and signs have been put up around the lake.
Possible side effects of the algae include skin rashes, eye irritation, vomiting, fever and diarrhoea.
A Natural Resources Wales (NRW) spokesman said: "We will continue to monitor conditions at the lake closely and will be taking regular samples to test for levels of the algae in the water.
"We are working closely with all the relevant authorities to advise them on how to minimise the risk to both the environment and local people."
The lake, measuring some 30 acres (12 hectares), is at the heart of Roath Park and is popular for fishing and boating.
A Cardiff council spokesperson said: "Roath Park Lake has been closed since last Tuesday as a precautionary measure, following the identification of blue-green algae in the water.
"Blue-green algae is a natural inhabitant of many inland waters, estuaries, and the sea and under certain environmental conditions such as high temperatures, low wind speeds, and low river flows, algal populations can grow rapidly.
"This excessive growth can be particularly common at this time of year and is known as a 'bloom'.
"Natural Resources Wales are carrying regular water tests and it is expected that normal water levels will resume over the next few weeks when the lake can be re-opened for re-creational use.
"Roath Park Lake has been hugely popular over the summer attracting record attendances. It has seen an increase in wildfowl presence and prior to the algae has enjoyed overall improvement in water quality."
The Scott Memorial Lighthouse on the lake is, according to the council, one of Cardiff's iconic images.
Roath Park opened in 1894.