Which toxic gas is produced during anaerobic decomposition?

During anaerobic decomposition, organic matter breaks down in the absence of oxygen, leading to the production of several gases. One of the primary gases produced in this process is Hydrogen Sulfide (H2S). This compound results from the microbial breakdown of organic material, particularly when sulfate-reducing bacteria are active. H2S is known for its distinct rotten egg smell and can be toxic to humans and other living organisms at high concentrations.

The other gases listed do not typically result from anaerobic decomposition. For example, Sulfur Dioxide (SO2) is generally associated with the combustion of fossil fuels and certain industrial processes, rather than anaerobic microbial action. Carbon Monoxide (CO), a product of incomplete combustion, is also not a primary gas produced during anaerobic decomposition. Chlorine (Cl2), a chemical used in water treatment and sanitation, is not produced in significant amounts as a byproduct of anaerobic decay processes. Thus, the correct identification of Hydrogen Sulfide (H2S) as the gas produced during anaerobic decomposition reflects a fundamental understanding of microbiological processes in waste management and environmental science.