Six river swimming spots are to be officially designated as bathing sites by the government this summer, despite 12 of 14 existing river bathing sites being unusable due to pollution. Signs advising people to stay out of the water have been installed at these 12 sites after tests raised concerns about contamination from bacteria linked to human and animal faeces – indicating sewage and/or agricultural runoff was contaminating the water . The warnings come as the government confirms that six new river locations, including the first on the River Thames in London, will be monitored for the first time this season. The government's records show that among river bathing sites, only the River Stour in Suffolk and a stretch of the River Thames in Oxfordshire met acceptable standards last year. Water quality at the remaining 12 was rated “poor”, with swimmers advised to avoid entering the water.…