E. coli represents the presence of what?

E. coli is a type of bacteria that serves as a key indicator of fecal contamination in water. Its presence is commonly used in microbiological testing to assess the safety and cleanliness of water sources, particularly in the context of wastewater treatment and environmental monitoring. When E. coli is detected, it often suggests that fecal matter, which may contain harmful pathogens, has entered the water system. This contamination can arise from various sources, including sewage discharges, agricultural runoff, or inadequate wastewater treatment processes.

In contrast, heavy metals, pesticides, and nutrients do not directly correlate with the presence of E. coli. While these substances can also contaminate water and may pose health risks, they are indicative of different types of pollution and do not specifically signify fecal contamination. Understanding the role of E. coli is crucial for water quality assessment and helps in developing strategies for water treatment and public health protection.