CNA938 Rewind - How does E. coli turn up in open waters?

The World Aquatics Championships open water events have proceeded this afternoon as planned, after water quality results showed significant improvement. The sport's governing body said that the results from three samples taken along the competition course at 5 p.m on Tuesday showed the levels of E. coli bacteria falling between the ranges of "good" to "excellent". But how does E.coli appear in open water bodies like Sentosa? Lance Alexander and Daniel Martin find out from Professor Hu Jiangyong, Department of Civil and Environmental Engineering, NUS.