Global metagenomic survey identifies sewage-derived hgcAB+ microorganisms as key contributors to riverine methylmercury production

Methylmercury (MeHg) in aquatic systems poses a serious public health risk through bioaccumulation in the aquatic food web. MeHg in rivers near cities around the world have risen to concerning levels in recent years. However, the reasons for this increase remain unclear. SKLMP Member Prof. Zhiguo Yuan from the School of Energy and Environment of City University of Hong Kong, in collaboration with the team led by Prof. Feng Jiang of Sun Yat-sen University, revealed the significant impact of sewage contamination by analyzing more than 1,300 publicly available metagenomes in urban rivers worldwide and conducting experiments with water samples across China. Relevant research findings have been published in Nature Communications and picked by the editor as a highlight.

The research team found that sewage contamination significantly increases the abundance of mercury-methylating microorganisms in urban rivers globally. This increase is mainly attributed to the high abundance of active mercury-methylating microorganisms in sewage, which migrate to rivers through direct discharge or combined sewer overflows, becoming key contributors to elevated riverine MeHg levels. The findings highlight the importance of the effective removal of mercury-methylating microorganisms from sewage to mitigate the public health risks associated with MeHg in urban rivers.

More information: https://doi.org/10.1038/s41467-024-53479-9