A conservationist has said he is "grieving" the loss of the urban wetland at Sean Walsh Memorial Park in Tallaght - and says South Dublin County Council is to blame.
Conservationists have accused the council of dumping condoms, plastic and batteries, on the diverse habitat, "killing" thousands of creatures, including endangered eels.
Collie Ennis, a science officer with the Herpetological Society of Ireland (HSI), said he was "grieving" yesterday after the destruction of the green space.
Shocking video and photographs posted online showed the area, which had been brimful of wildlife, including endangered European eels, had been destroyed, trampled by machinery.
The HSI last night said the initial discovery was even more "shocking" as its investigation on the land continued.
"The Environmental Protection Agency need to get involved here, as the dredged waste is full of toxic materials, plastic and household waste.
"We've seen batteries, rebar (steel mesh), tablet packs, condoms, you name it, it's there.
"It's very clear there was no screening the material prior to it being dumped. Essentially, an incredibly diverse habitat has been destroyed…"
Mr Ennis, a research associate at Trinity College, said it was hard to believe how anyone could "drive a truck full of sludge onto wetland full of birds, bees and butterflies and not stop and see the beauty being destroyed".
He said the message the local authority had sent out to residents was "why bother recycling when your council took a load of waste and dumped it on a local wildlife area?"
"Thousands of species of wildlife have been killed, buried alive," he said. "I saw a confused-looking fox today, which I hope hasn't got a set there.
"We saw a pond drained and there's a lot of birdlife tip-toeing around in mud. It's just devastating, shocking. We need to take a step back. Stop with the greenwashing, the council and Government needs to listen to conservationists and hire them to help instead of making biodiversity a box-ticking exercise."
He labelled the situation an "unmitigated disaster".
He described the area as a "haven, an oasis" which had been filled with frogs, newts, bats and eels and had been naturally decorated with an abundance of wild flowers.
Mayor of South Dublin County Council Vicki Casserly said: "I've put it to the council for an update on why this has happened.
"The council launched a climate action plan, so I'm very interested to see what's taken place here and to see what steps will now be taken and if they will rebuild the area."