Mercury methylation and methylmercury demethylation in boreal lake sediment with legacy sulphate pollution

Huang, Haiyong; Mangal, Vaughn; Rennie, Michael D.; Tong, Huan; Simpson, Myrna J.; Mitchell, Carl P. J.

doi:10.1039/d2em00064d

Cited by 7 publications

(2 citation statements)

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“…−2 ]). A number of studies (Benoit et al 1999;Li and Cai 2012;Poulin et al 2017;Jones et al 2020;Huang et al 2022;Janssen et al 2022) have led to the development of a general paradigm that lakes or wetlands with lower concentrations of SO 4…”

Section: Controls Of Period Of Inundation On Mehg Concentrationsmentioning

confidence: 99%

“…Historically, only sulfur-reducing bacteria (SRB), iron-reducing bacteria, and methanogens were identified methylators; more recently many bacteria and archaea have been shown to possess the gene pair (hgcAB) necessary for Hg methylation (Hamelin et al 2011;Gilmour et al 2013;Peterson et al 2020). MeHg is also demethylated to reactive HgII or elemental Hg via a diverse suite of bacterial processes (Oremland et al 1991;Huang et al 2022) or abiotically from sunlight exposure (Sellers et al 1996) such that the MeHg available to biota is the net result of these two processes.…”

Section: Introductionmentioning

confidence: 99%

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Wet–dry cycles influence methylmercury concentrations in water in seasonal prairie wetland ponds

Hall

Liu

Hoggarth

et al. 2023

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Methylmercury concentrations [MeHg] in whole water were measured in 28 prairie wetland ponds in central Saskatchewan between 2006 and 2012. Ponds fell into four land use categories (established grass, recent grass, traditional cultivated, and certified organic cultivated) and two water level patterns (“Mainly Wet” ponds stayed wet at least until October and “Mainly Dry” ponds dried up each summer). Despite similar atmospheric Hg deposition, average [MeHg] and proportion of total Hg that was MeHg (%MeHg) were higher in water from ponds surrounded with established grass or organic farming; this trend may be driven by high [MeHg] at one Organic site. A stronger relationship was observed with water level patterns. Average [MeHg] and %MeHg were significantly higher in Mainly Wet ponds compared to Mainly Dry ponds. Higher [MeHg] in Mainly Wet ponds were correlated with much higher dissolved organic carbon (DOC) and sulfate (SO4−2) concentrations and higher specific UV absorbance of DOC. We suggest that prairie wetland ponds may not fit the accepted paradigm that wetlands with high [SO4−2] show inhibition of Hg methylation. Our work suggests controls such as the chemical nature of DOC or redox fluctuations in hydrologically dynamic systems may be important in determining net [MeHg] in these sites.

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