Blue-Green Algae Toxicity
Friends of Wimbledon Park were very saddened to hear of a dog that recently suffered toxic poisoning from blue-green algae in Wimbledon Park. The dog in question was taken straight to a local veterinary but still nearly died and is now suffering paralysis.
Please keep your dogs and children out of the lake and streams while this threat continues. We will be asking Merton council to put up more signs and take further action e.g. pro-active monitoring.
Please see the PDSA website for further information.
Dr. David Dawson
Our local environmental scientist Dr. David Dawson made the following statement:
“I have been monitoring water quality of Wimbledon Park Lake for six years and have warned of blooms of Blue-green algae (now known to be bacteria) several times.
The Council put up little warning notices in response, but don’t monitor water quality themselves.
Only in two years of the six has the summer bacterial bloom been missing. It looks as if the lake is declining badly, because the last three summers have had blooms. The problem is excessive nutrients in the lake.
No-one is studying where the nutrients come from, but it will not get better if the All England Lawn Tennis Club get permission for their 38 new courts on the golf course, because the intensive management of those courts involves much use of fertiliser and there is no effective proposals to stop these leaching into the nearby lake.
It’s likely also that misconnections and storm overflows allow sewage and other nutrients to flow down to the lake from the underground brooks that feed it. The Environment Agency does nothing about this.
Nutrients are locked away in the sediment on the bottom of the lake and these can be disturbed by fish feeding or the watersports people cutting waterweeds.
Dogs are most at risk, but people can also suffer and I have found big effects on the tiny water life that the fish feed upon.
Unfortunately, it is difficult to tell toxic blue-greens from their safe relatives. I have identified three species in our lake and this year a bright green one has predominated. It’s called Dolichospermum sprioides. I agree that more prominent warning notices are needed, even though we are not able to tell which blue-greens will prove to be toxic. Unfortunately, the blooms make activities like watersports and angling dubiously safe.
In response to Freedom of Information requests, LB Merton said that they don’t test water quality in the lake.
I have reported previous blooms in my blog, and also alerted the Council to the danger two years ago, which is when the little notices first appeared. I got no thanks nor acknowledgement for alerting them.
The blooms come from the lake, as the bacteria do not thrive in running water. But the brook and waterfall originate from the nearby lake, so the blooms are found there.
The incidents with dogs show just how unpredictable are poisoning events. I have found three species of blue-green in the lake in previous years, but this is the first time I have heard of a poisoning here. It could be that Dolichospermum is the problem. In previous years it was there, but not the main species.
It’s not just dogs, I fear for the safety of those undertaking watersports, angling and, dare I say, free swimming. Small children feeding the birds could also be at risk.
As an environmental scientist, I take appropriate precautions when sampling the lake water. It’s second nature to me.”
