16 research outputs found
Methylation index as means of quantification of the compliance of sedimentary mercury to be methylated
Patients with the most advanced rheumatoid arthritis remain with Th1 systemic defects after TNF inhibitors treatment despite clinical improvement
Methods and recent advances in speciation analysis of mercury chemical species in environmental samples: a review
Highly ordered carbon nanotubes to improve the conductivity of LiNi0.8Co0.15Al0.05O2 for Li-ion batteries
Geobacteraceae are important members of mercury-methylating microbial communities of sediments impacted by waste water releases
Microbial mercury (Hg) methylation in sediments can result in bioaccumulation of the neurotoxin methylmercury (MMHg) in aquatic food webs. Recently, the discovery of the gene hgcA, required for Hg methylation, revealed that the diversity of Hg methylators is much broader than previously thought. However, little is known about the identity of Hg-methylating microbial organisms and the environmental factors controlling their activity and distribution in lakes. Here, we combined high-throughput sequencing of 16S rRNA and hgcA genes with the chemical characterization of sediments impacted by a waste water treatment plant that releases significant amounts of organic matter and iron. Our results highlight that the ferruginous geochemical conditions prevailing at 1–2 cm depth are conducive to MMHg formation and that the Hgmethylating guild is composed of iron and sulfur-transforming bacteria, syntrophs, and methanogens. Deltaproteobacteria, notably Geobacteraceae, dominated the hgcA carrying communities, while sulfate reducers constituted only a minor component, despite being considered the main Hg methylators in many anoxic aquatic environments. Because iron is widely applied in waste water treatment, the importance of Geobacteraceae for Hg methylation and the complexity of Hgmethylating communities reported here are likely to occur worldwide in sediments impacted by waste water treatment plant discharges and in iron-rich sediments in general