Solar and Temporal Effects on Escherichia coli Concentration at a Lake Michigan Swimming Beach

摘要: Studies on solar inactivation of Escherichia coli in freshwater and situ have been limited. At 63rd St. Beach, Chicago, Ill., factors influencing the daily periodicity culturable E. coli, particularly insolation, were examined. Water samples for analysis collected twice between April September 2000 three times a week along five transects two depths water. Hydrometeorological conditions continuously logged: UV radiation, total wind speed direction, wave height, relative lake level. On 10 days, sampled hourly from 0700 to 1500 h. The effect sunlight was evaluated with dark transparent mesocosms ambient For study, number (n) 2,676. During sunny counts decreased exponentially day length exposure but cloudy diminished; decay rate strongly influenced by initial concentration. In experiments confirmed that insolation primarily inactivated coli; radiation only marginally affected relationship density is complicated level, turbidity, all which are often products vector. Continuous importation nighttime replenishment evident. These findings (i) suggest an important mechanism natural reduction indicator bacteria large bodies (ii) implications management strategies nontidal waters use as organism.