Which release compounds can enhance the natural attenuation of tetrachloroethene compounds?

Hydrogen release compounds are particularly effective in enhancing the natural attenuation of tetrachloroethene (PCE) due to their role in facilitating reductive dechlorination. This is a microbial process where specific bacteria utilize hydrogen as an electron donor to metabolize chlorinated solvents, including PCE. During this process, PCE is converted into less harmful compounds through a series of biochemical reactions facilitated by the presence of hydrogen.

The presence of hydrogen in the subsurface environment encourages anaerobic microbial communities that are specialized in breaking down chlorinated compounds. These microbes thrive and become more active when sufficient hydrogen is available, leading to more efficient degradation of PCE and related contaminants.

While other release compounds such as oxygen, nitrogen, or carbon might play roles in biogeochemical processes, they do not specifically stimulate the dechlorination pathway in the same effective manner as hydrogen release compounds do in the context of remediation of chlorinated solvents like PCE. Oxygen, for instance, can support aerobic processes and may lead to different metabolic pathways that do not favor the breakdown of PCE, while nitrogen and carbon release compounds do not directly contribute to the reductive dechlorination of such halogenated compounds.