The worst sampled was Blenheim s Doctors Creek, with more than half its attributes falling below the national standard, including an ‘E’ for E Coli – a bacteria which indicated there was faecal matter in the water. To be given this grading, Doctors Creek’s faecal bacteria count exceeds the safe swimming levels more than 30 per cent of the time. Contaminants were likely coming from farm animals, ducks and maybe humans, according to a report from an environment meeting last month. The creek was also the only one to return high scores of phosphorus. The chemical was a favourite of algae, encouraging it to grow and suck up oxygen, which suffocated fish and sometimes led to toxic blooms.