Which gas commonly found in water is associated with a rotten egg odor?

Which gas commonly found in water is associated with a rotten egg odor?

• A. Oxygen (O2)
• B. Hydrogen sulfide (H2S)
• C. Carbon dioxide (CO2)
• D. Methane (CH4)

Answer: (B)

Rotten-egg smell in water comes from hydrogen sulfide. This gas is produced by anaerobic bacteria and chemical processes that release sulfur, especially in groundwater or in systems where organic matter decomposes without oxygen. Among common gases found in water, hydrogen sulfide is the one that gives that distinctive sulfurous odor; oxygen and carbon dioxide are odorless, and methane is typically odorless as well. The presence of hydrogen sulfide is a clue to sulfide-related taste and odor issues and possible corrosion concerns, and it can be detected even at very low concentrations (though smell can fade at higher exposures, so testing is important).

Rotten-egg smell in water comes from hydrogen sulfide. This gas is produced by anaerobic bacteria and chemical processes that release sulfur, especially in groundwater or in systems where organic matter decomposes without oxygen. Among common gases found in water, hydrogen sulfide is the one that gives that distinctive sulfurous odor; oxygen and carbon dioxide are odorless, and methane is typically odorless as well. The presence of hydrogen sulfide is a clue to sulfide-related taste and odor issues and possible corrosion concerns, and it can be detected even at very low concentrations (though smell can fade at higher exposures, so testing is important).