Which of the following is an indicator of potential pathogenic organisms in water?

The correct answer is coliform bacteria, which are widely recognized as key indicators of potential pathogenic organisms in water. Coliform bacteria are a group of bacteria commonly found in the intestines of warm-blooded animals and in the environment. Their presence in water indicates that there may be contamination with fecal matter, which can harbor harmful pathogens, including viruses, bacteria, and protozoa that can pose serious health risks.

Monitoring for coliform bacteria allows water utilities to assess the safety of drinking water and to take necessary corrective actions when these organisms are detected. Testing for coliform bacteria is relatively easy and cost-effective, making it a standard practice in water quality monitoring.

In contrast, while nematodes may also be found in contaminated water, they are not a reliable indicator of fecal contamination or pathogenic organisms. Nitrates and phosphates, on the other hand, primarily indicate nutrient levels in water rather than the presence of harmful pathogens. Nitrates can arise from agricultural runoff and indicate potential issues with nutrient pollution, while phosphates often indicate similar concerns but are not linked to fecal contamination or pathogens. Thus, coliform bacteria stand out as the most relevant indicator for assessing the microbiological safety of water supplies.