What is used as an indicator to determine possible contamination in the drinking water?

• A. Chloride
• B. Coliform bacteria
• C. Turbidity
• D. pH

Answer: (B)

Coliform bacteria are used as indicators of possible contamination in drinking water because their presence signals that the water system’s barriers against contamination may have been breached and that conditions could allow pathogens to be present. They’re not necessarily harmful themselves, but they’re easy to detect and correlate with fecal contamination or intrusion from the environment, warranting further testing for specific fecal indicators (like E. coli) and triggering corrective actions to protect public health.

Chloride measures salinity, not contamination. Turbidity reflects how clear or cloudy the water is, which can hint at particulates but isn’t a direct contamination indicator. pH tells how acidic or basic the water is, influencing corrosion and disinfection but not serving as a direct sign that contamination has occurred.