A Local Government Ombudsman report issued this month into the canoe slalom at the National Water Sports Centre in Nottingham revealed that as many as 40 per cent of users had subsequently fallen ill, some seriously.
The Government is responding to pressure by teacher Alex Redhead who has campaigned to get the stretch of water at Holme Pierrepont closed to children. Schools still use the slalom course.
One user lost one and a half stone in weight, passed blood and took two months to recover.
Young people are among those believed to have developed Weil's disease after using the canoe stretch. The disease causes fever, jaundice and muscle pain. It is transmitted by rats via contaminated water and can be fatal.
Anyta Rogers, the Welsh white water canoe slalom champion, spent at least a day in bed everytime she used the site.
Ms Rogers said: "Personally I would like it shut down. " The Local Government Ombudsman report noted that users developed health problems from the outset.
It concluded that it was "disturbing" that it took from November 1994 to May 1996 for a draft of the risk assessment to be produced by Rushcliffe Borough Council.
Yet about a third of the 85 cases reported by schools, canoe clubs, RAF personnel and national slalom teams, were not relayed to the borough council by the English Sports Council, which runs the site.
Water contamination was regularly in breach of EU guidelines for bathing water.
The report states that even before the Pounds 2.2 million canoe run was built, the Trent did not meet EU standards for bathing water.
The ESC now has signs warning users of health risks and claims a few schools are registering for use. But many could still be turning up and using the facilities with no records being taken.
The sports council was not responsible for the water that flowed from the Trent directly into the canoe slalom, the report concluded.
An improvement notice under the Health and Safety at Work Act, was not necessary, it added, as warnings and notices meant this in effect had already been carried out.
The Environment Agency concluded in April 1996 that the river contained a high proportion of treated sewage. This can wash downstream into the canoe strait.
Those that fall ill after using the Holme Pierrepont site typically develop gastric problems, such as being violently sick and feeling exhausted for days.
Mr Redhead from the Lakes School, Windermere, found several boys fell ill after he took them to the site, in October 1994.
Anyone with any questions about using the site should contact Martin Elliott of the DFEE on 0171 925 5886