If a routine or repeat sample tests positive for total coliforms, it must also be analyzed for _______.

If a routine or repeat sample tests positive for total coliforms, it must also be analyzed for _______.

• A. fecal coliforms and E. Coli
• B. repeat coliform test and fecal coliforms
• C. fecal coliforms
• D. E. Coli

Answer: (C)

Total coliforms are used as an initial indicator of a water sample’s sanitary quality. When a routine or repeat sample comes back positive for total coliforms, the next step is to determine whether fecal contamination is present. This is done by analyzing for fecal coliforms, which are a subset of total coliforms that originate in the intestines of warm-blooded animals. Their presence more directly signals fecal pollution and a higher potential for pathogenic organisms, guiding the appropriate response and treatment actions. While E. coli is itself a type of fecal coliform, the standard follow-up is to test for the broader fecal coliform group rather than for E. coli alone, making fecal coliforms the best choice here.

Total coliforms are used as an initial indicator of a water sample’s sanitary quality. When a routine or repeat sample comes back positive for total coliforms, the next step is to determine whether fecal contamination is present. This is done by analyzing for fecal coliforms, which are a subset of total coliforms that originate in the intestines of warm-blooded animals. Their presence more directly signals fecal pollution and a higher potential for pathogenic organisms, guiding the appropriate response and treatment actions. While E. coli is itself a type of fecal coliform, the standard follow-up is to test for the broader fecal coliform group rather than for E. coli alone, making fecal coliforms the best choice here.