Toxic waste leaking into the River Clyde poses an immediate risk to human health, a report has stated.
Regeneration agency Clyde Gateway found poisons are entering the river from the ground of a former chemical factory in Rutherglen, South Lanarkshire.
Among the elements discovered in the toxins is chromium-VI, which can cause cancer in humans.
Clyde Gateway said the chemical waste originated from the former Shawfield Chemical Works that has been closed for more than 50 years.
In a blunt report given to MPs, MSPs and councils, the agency said: "The nature of the contamination poses immediate or long-term risks to human health and the environment through land, surface water or groundwater pollution."
The Scottish Government-funded partnership between two councils and Scottish Enterprise is aiming to regenerate an 840-hectare area in the east end of Glasgow and neighbouring South Lanarkshire.
Clyde Gateway has already been working on diverting underground burns but said that, without public-sector intervention, sites in the area will not be capable of development and "contamination will continue to blight communities and pose a health issue for local residents".
The report estimates that further development and decontamination in the area could cost £54.2m, with the next phase of work taking place where the former J & J White Chemicals plant was based from 1820 until 1967
A Clyde Gateway spokesperson said: "It had a long and often controversial history, the legacy of which has left an environmental headache which must be addressed in some shape or form, given that the poisons in the ground are leaching into underground streams and polluting the Clyde, putting at risk the successful strategy to have the river as the focus of so much of the city's economic rebirth."
They added that the company was known to dump waste materials across Rutherglen, Cambuslang and east Glasgow, often in old quarries or mines.
The issue of chromium in the water at Shawfield gained attention in February when water at Polmadie Burn - where children had been reportedly playing - was unnaturally green due to high levels of the dangerous chemical.
The Scottish Environment Protection Agency and Glasgow City Council have been draining the burn into the Clyde at low tide and the council has cordoned off the area until a permanent solution can be found.