Effect of low concentration 17β-estradiol on the emissions of CH₄ and CO₂ in anaerobic sediments.

The estrogen17β-estradiol (E2) is one of the most widely distributed natural estrogens and is the most potent estrogen in the environment. For the present study, methanogenic bacteria communities were chosen as study objects to analyze the effects of E2 on the production of methane and carbon dioxide. Microecological systems in anaerobic pore water were constructed in the laboratory. The results show that E2 played an enhancing role in methanogenic activity when the concentrations were ≤0.5 ng/L. The enhancement was the strongest at 0.3 ng/L. However, when the E2 concentration exceeded 1.0 ng/L, it inhibited the methanogenic activities of bacteria. The inhibition effect persisted for up to 264 h, beyond which the trend became unclear. On the other hand, E2 has an inhibition effect on CO₂ production in anaerobic sediments, which indicates that E2 had a significant inhibition effect on microbial activities under anaerobic conditions. Based on these experiments, the authors believe that E2 in anaerobic sediments can affect sediment microbial activities and therefore influence the self-purification of water bodies and methane ebullition.