What type of contaminants might be found in unchlorinated water supplies?

Chlorination is a key process in water treatment that aims to eliminate or reduce pathogenic microorganisms, including bacteria, viruses, and protozoa, that can cause illnesses in humans. When water supplies are unchlorinated, they are particularly susceptible to contamination by these pathogens due to their ability to survive and multiply in water sources.

Pathogenic bacteria include organisms such as E. coli, Salmonella, and Giardia. These can originate from various sources, including animal waste, sewage, or surface water runoff. The absence of chlorine allows these pathogens to thrive, which can pose serious health risks to individuals consuming or using the unchlorinated water.

While insecticides, chlorides, and heavy metals can be present in water supplies, they are not as directly associated with the lack of chlorination as pathogenic bacteria. Insecticides may enter water through agricultural runoff, chlorides can be naturally occurring or from road salt, and heavy metals are primarily linked to industrial pollution or corrosion of plumbing systems. Thus, the connection of pathogenic bacteria to unchlorinated water highlights the critical importance of disinfection in safeguarding public health.