The shareholders at WWA are increasingly concerned about the organisation's involvement in the handling and testing of bathing water samples. this work is attracting bad publicity and they have asked for an update to reassure them. a) prepare a short briefing note to the shareholders on E.coli 0157 outlining the i) type of biological agent. (2) ii) sources (2) iii) properties (2) iv) the possible ill- health effects of exposure to E.coli 0157 (4)

b) posts on social media from swimmers who swam at Green Valley Lake in the first two weeks of June, report that many have since been ill. the swimmers are reporting stomach pain, but others are more unwell. i) Explain how these swimmers at Green Valley Lake have become ill. (15)

later in June, social media posts from some of the same swimmers report members of their family, who had not been swimming,are now also unwell. ii) Suggest likely explanations for this (10) iii) Suggest reasons why the water sampling results for White Cliff Cove differ significantly from those for Green Valley Lake in the same two weeks of June (4)

c) Suggest why the workers handling bathing water samples in Lab 4 are at a lower risk of becoming ill than thise people who swim in Green Valley lake (6)