BTEC 223 Lab Exercise Water Module Water Quality Fecal Indicator Test Yeggie Dearborn EMSA 22 CCSF

Parameters: Fecal Indicator Fecal indicator bacteria are used to assess the microbiological quality of water because, although not typically disease causing, they are correlated with the presence of several waterborne disease-causing organisms. The concentration of indicator bacteria is a measure of water safety for body-contact recreation or for consumption Enterococcus causes illness in humans True or false? False Enterococcus is an indicator of fecal contamination; it does not cause illness directly E. coli can be used as an indicator of fecal contamination in both fresh and marine waters  True  False E. coli is a valid indicator in fresh waters only

Criteria for selecting an indicator of fecal contamination in water The preferred fecal indicator: Can be tested easily Is of human or other animal origin Survives as long as, or longer than, pathogens Is present at densities correlated with fecal contamination Is appropriate for fresh and saline aqueous environments Criteria for selecting an indicator of fecal contamination in water

Indicator Bacteria Total Coliform Bacteria Fecal Coliform Bacteria (subset of Total coliform) E.coli ( a fecal coliform indicator) Fecal Streptococci Enterococci (a fecal indicator) The presence in water of E. coli, and often enterococci, is direct evidence of fecal contamination from warm-blooded animals.

Which Fecal indicator to use? Type of indicator to use depends on regulation associated with the water type being tested Recreational water: Enterococci Shellfish growing water: Total Coliform, Fecal Coliform Drinking water : total coliform if present them E.coli Public water system may be required to test for viruses and parasites

Lab Demonstration : Presence/Absence Coliform analysis of Recreational water Last Saturday we collected two water (ocean) samples for E.coli & Enterococci (Both fecal coliforms) We will look at the results and compare with Known Positive samples -Test kit for Coliform analysis (Presence/absence) method follow protocol

Lab Report Prepare a two page report with following components: -Introduction- Brief background on Coliforms in recreational water -Sample collection procedure -Analysis procedure -Results/Discussion of results including EPA requirement for maximum contaminant for coliforms and fecal coliforms in recreational water & what is needed to be done if fecal coliforms are present in the sample.