A high concentration of fecal coliforms was found in a lake in a rural district. The lake
is used for recreation and for drinking water. In order to select a management
approach, the authorities want to identify the source of fecal contamination and find
out whether it comes from domestic sewage leakage, from cows that feed too close to the lake, or from the high numbers of migrating birds. Which culture independent method would be best to use?