Escherichia coli and fecal-coliform bacteria as indicators of recreational water quality

Introduction 2 Purpose and scope 3 Review of previous investigations 4 Epidemiological studies and the development of recreational water-quality criteria 4 Recent epidemiological studies 6 Comparisons of Escherichia coli and fecal-coliform concentrations 9 Methods of study 11 Sample collection and analysis 11 Statistical methods 13 Relation of Escherichia coli concentrations to fecal-coliform concentrations 15 Predictions of Escherichia coli from fecal-coliform concentrations and the relation of these concentrations to Ohio water-quality standards 22 Risk of illness based on predictions of Escherichia coli concentrations 27 Summary and conclusions 31 References cited 33 ILLUSTRATIONS Figure 1.Map showing locations of sample-collection sites in the Columbus, Ohio, area; the Cleveland-Akron, Ohio, area; and the Cincinnati, Ohio, area 12 2. Graphs showing regression relation between Escherichia coli and fecal-coliform concentrations in the Cuyahoga River, in the Olentangy River, in the Scioto River, and for pooled U.S. Geological Survey data ~ --16-17 3. Graphs showing regression relation between Escherichia coli and fecal-coliform concentrations at Cincinnati Water Works and Tanners Creek, at Anderson Ferry, and for pooled Ohio River Valley Water Sanitation Commission data 18-19 4. Graph showing regression relations between Escherichia coli and fecal-coliform concentrations for U.S. Geological Survey and Ohio River Valley Water Sanitation Commission data 23 5-6.Graphs showing confidence and prediction intervals for Escherichia coli concentrations calculated from the fecal-colifoTm/Escherichia coli regression relations for: 5. Pooled U.S. Geological Survey data 25 6.Pooled Ohio River Valley Water Sanitation Commission data 26 in ILLUSTRATIONS-Continued Page 7-8.Graphs showing samples that exceeded Ohio water-quality standards for Escherichia coli when fecal-coliform standards were met for bathing waters and primary-contact recreation: 7. Evaluated by use of U.S. Geological Survey data and geometric-mean standards 29 8. Evaluated by use of Ohio River Valley Water Sanitation Commission data and geometric-mean standards 30