What chemical is added to bacteriological sample bottles to dechlorinate water?

Sodium thiosulfate is used to dechlorinate water in bacteriological sample bottles because it effectively neutralizes chlorine, which can be present in water supplies as a disinfectant. If chlorine is not removed, it can kill bacteria present in the sample and lead to inaccurate results in microbiological testing. Sodium thiosulfate works by reacting with chlorine compounds, converting them into harmless substances that do not interfere with the analysis of the water sample. This is crucial in water quality monitoring and ensuring the reliability of bacteriological assessments. Other options do not serve this specific purpose; potassium permanganate is an oxidizing agent and could interfere with tests, chloramine is a form of chlorine and would not dechlorinate, and calcium chloride does not have the dechlorination capability.