At present, hundreds of rowers, kayakers and sailors use the Thames regularly and the risks to their health are poorly defined, the HPA says.
Gastrointestinal illness has previously been linked with exposure to contaminated seawater on bathing beaches, and smaller studies have confirmed illness in white water kayakers, but no study of this scale has yet been performed on a tidal river like the Thames.
Contamination of the river has been a long standing problem due to the aged system of combined overflows of untreated sewage and rainwater run-off leading to mass discharges every time London receives heavy rainfall. This happened most recently at the start of August (see RELATED STORY) when a heavy storm caused 600,000 tonnes of raw sewage to be washed into the Thames killing thousands of fish due to depleted oxygen levels.
Currently, the HPA advises people not to use the Thames tideway for recreational purposes following heavy rainfall in the London region, and to allow sufficient time for the river to clear.
The results of the study will be published in peer-reviewed scientific journals and will form the basis of advice for those who use the Thames for recreational purposes.
By David Hopkins