Roath Park lake closed due to toxic bloom of blue-green algae

Blue-green algae has closed Roath Park's popular lake, and it also poses a risk to human and animal health. Source: Nick Dawson

by Nia Jones

Parkwood Outdoors, the company who operates activities on the lake, has been told by Cardiff Council to suspend all pedalo and rowing boat rentals until public health is no longer at risk. This comes at one of the busiest times of year for the park, the height of the school summer holidays.

The algae are naturally occurring in many inland water bodies, estuaries and seas especially during periods of hot weather with low amounts of rainfall.

What is blue-green algae?

With news-worthy blooms occurring off the coast of Florida in the US, and now throughout water bodies in the UK including the Lake District and here in Cardiff, a lot of people are asking what exactly is blue-green algae?

Blue-green algae is a name given to a group of bacteria called cyanobacteria. It is usually found in slow moving rivers and other still water bodies where there is warm water allowing for nutrients like nitrogen and phosphorus to grow.

It can only be seen when in high concentrations and will likely form layers or mats on top of the water, referred to as blooms.

Is it dangerous?

These blooms can produce toxins which can become a hazard to human and animal health. Exposure to the possible toxins released by the algae may cause skin rashes, nausea, vomiting, fever and headaches in humans with children being at a greater risk than adults.

Although not all blooms are toxic, precautions should be taken around contaminated water bodies to minimise possible exposure.

If you do come into contact with the contaminated water, then medical attention should be sought immediately.

And what about our pets?

The algae can be poisonous to animals that are exposed to contaminated water causing severe illness of the stomach and internal organs which can be fatal, according to Public Health Wales.

If dogs are showing any of the following symptoms then they should be taken immediately to the vet: vomiting/being sick, diarrhoea, seizures/fitting, weakness/collapse/unconsciousness, disorientation/confusion, drooling and/or breathing difficulties.

To protect your dog from the serious effects of algal blooms it is advised that you should not allow your dog to swim, paddle or drink from the contaminated water source, keeping them on a lead around the lake during blooms.

When will things be back to normal?

Unfortunately, there is no ‘quick fix’ to control an algal bloom once it has appeared in a lake, although according to Parkwood Outdoors, daily testing of the water is being conducted to get people out on the lake again as soon as it is safe to do so.

A statement on Parkwood Outdoors website said: “Unfortunately we are closed until further notice due to the high concentration of blue-green algae in the lake.

“The lake is tested daily to determine if it safe for us to rent out the pedalos and row boats safely again. We will keep our website and social media updated with information with regards to when we will be reopening. We do hope that we will be able to re-open soon.

“We’re sorry for any inconvenience caused and we are looking into ways that we can speed up the process of getting rid of the blue green algae.”