After a comprehensive literature review, the Department published Fecal Contamination Source Identification Methods in Surface Water . We realized that we didn't have all of the answers, so we decided to develop a reference document for us and others to use. In the past, bacterial contamination of water was often blamed on sewage treatment plants, but today we know that many different sources can be to blame, including runoff from livestock operations, failing septic tanks, an overabundance of geese or deer, or other nonpoint sources. Sargeant compiled information on the available methods for identifying human versus nonhuman sources of fecal contamination in surface waters. The document describes each method, lists the advantages and disadvantages of each, and provides examples of application.
Different ratios indicate the presence of human or nonhuman bacteria.
Streptococcal Population Profiles. Species composition is used to indicate host animals. Composition varies among types of animals and has been quantified for human, nonhuman, and dairy. Some bacteria strains are specific to certain animal species and can be identified as originating within that animal group. For example, Rhodococcus coprophilus is primarily associated with domestic farm animal fecal pollution.