Mercury alkylation in freshwater sediments from Scottish canals

Abstract

Mercury concentrations were investigated in freshwater sediment from two canals in Scotland, UK. High concentrations found in the Union Canal (35.3-1200 mg kg) likely originate from historical munitions manufacture, with lower levels in the Forth & Clyde Canal (0.591-9.14 mg kg). Concentrations of methylmercury (MeHg) were low - from 6.02 to 18.6 μg kg (0.001-0.023% of total Hg) in the Union Canal and from 3.44 to 14.1 μg kg (0.11-0.58% of total Hg) in the Forth & Clyde Canal - and there was a significant inverse relationship between total Hg concentration and %MeHg. Total Hg concentration was significantly negatively correlated with pH and positively correlated with Fe content (in the Union Canal only) but not with organic matter, S content or the proportion of clay present. The MeHg concentration was not correlated with any of the above sediment parameters. Ethylmercury was detected in the most highly contaminated sediments from the Union Canal.

Mercury exposure and its effects on fertility and pregnancy outcome

“…When Hg is released into the natural environment, and in groundwater, microorganisms including bacteria are often responsible for the biotransformation of the metal leading to the formation of methylmercury (MeHg) . Methylmercury and ethylmercury (EtHg) are highly hazardous forms that accumulate in freshwaters, ecosystems and food chains, leading to Hg exposure in people and other natural living organisms . Worldwide, global recognition of the great concern caused by Hg pollution led to the adoption of the Minamata Convention on Mercury in 2017 .…”

“…6,7 Methylmercury and ethylmercury (EtHg) are highly hazardous forms that accumulate in freshwaters, ecosystems and food chains, leading to Hg exposure in people and other natural living organisms. [8][9][10] Worldwide, global recognition of the great concern caused by Hg pollution led to the adoption of the Minamata Convention on Mercury in 2017. 11 In July 2017, the 13th International Conference on Mercury as a Global Pollutant, which was held in the United States, was devoted to integrating Hg science and politics in the modern world.…”

Assessing Mercury Mobility in Sediment of the Union Canal, Scotland, UK by Sequential Extraction and Thermal Desorption

“…Location 1 was part of a canal extension added in 2000-2001 as part of the canal regeneration. Sediment samples were collected and processed as described in Cavoura et al (2017) i.e. they were dried at 30 ⁰C in a natural convection oven, sieved to <2 mm and stored in glass bottles at room temperature.…”

“…Following substantial redevelopment and regeneration in 2001-2002, which included dredging of sediment and soil excavation, the canal has become a major leisure facility used for boating and fishing. However, despite these remediation efforts, very high levels of Hg contamination persist in sediment close to the location of the former munitions factory (Cavoura et al 2017). Methyl mercury levels in the canal sediments are currently low (Cavoura et al 2017).…”

“…However, despite these remediation efforts, very high levels of Hg contamination persist in sediment close to the location of the former munitions factory (Cavoura et al 2017). Methyl mercury levels in the canal sediments are currently low (Cavoura et al 2017). However it is important that the mobility of Hg species present be determined to assess the likelihood of transport and potential for methylation.…”