Role of ultra-violet radiation, mercury and copper on the stability of dissolved glutathione in natural and artificial freshwater and saltwater

Moingt, Matthieu; Bressac, Matthieu; Bélanger, Denise; Amyot, Marc

doi:10.1016/j.chemosphere.2010.06.041

Cited by 24 publications

(19 citation statements)

References 38 publications

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“…52 This thiol degradation could have been caused by ROS produced from irradiated organic matter, 52 which could have contributed to PD.…”

Section: Ecosystem-scale Observations Of Photodemethylationmentioning

confidence: 99%

“…Indeed, some metals such as copper may affect the oxidation states of GSH and potentially lead to other degradation products. 18,52 In BYL ponds, GSH may have been partly degraded before being able to fully intervene in PD.…”

Section: Thiols and Photodemethylationmentioning

confidence: 99%

“…In temperate lake water, GSH was also simultaneously degraded during exposure to light (approximately 30% after 5 hours) (SI, Figure S6), as has been previously reported. 52 GSH degradation can depend on the matrix and on other ions present. Indeed, some metals such as copper may affect the oxidation states of GSH and potentially lead to other degradation products.…”

Section: Thiols and Photodemethylationmentioning

confidence: 99%

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Photodemethylation of Methylmercury in Eastern Canadian Arctic Thaw Pond and Lake Ecosystems

Girard

Leclerc

Amyot

2016

Environ. Sci. Technol.

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Permafrost thaw ponds of the warming Eastern Canadian Arctic are major landscape constituents and often display high levels of methylmercury (MeHg). We examined photodegradation potentials in high-dissolved organic matter (DOC) thaw ponds on Bylot Island (BYL) and a low-DOC oligotrophic lake on Cornwallis Island (Char Lake). In BYL, the ambient MeHg photodemethylation (PD) rate over 48 h of solar exposure was 6.1 × 10 -3 m 2 E -1 , and the rate in MeHg amended samples was 9.3 × 10 -3 m 2 E -1 . In contrast, in low-DOC Char Lake, PD was only observed in the first 12 hours, which suggests that PD may not be an important loss process in polar desert lakes. Thioglycolic acid addition slowed PD, while glutathione and chlorides did not impact northern PD rates. During an ecosystem-wide experiment conducted in a covered BYL pond, there was neither net MeHg increase in the dark nor loss attributable to PD following reexposure to sunlight. We propose that high-DOC Arctic thaw ponds are more prone to MeHg PD than nearby oligotrophic lakes, likely through photoproduction of reactive species rather than via thiol complexation. However, at the ecosystem level, these ponds, which are widespread through the Arctic, remain likely sources of MeHg for neighbouring systems.3

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“…52 This thiol degradation could have been caused by ROS produced from irradiated organic matter, 52 which could have contributed to PD.…”

Section: Ecosystem-scale Observations Of Photodemethylationmentioning

confidence: 99%

Section: Thiols and Photodemethylationmentioning

confidence: 99%

Section: Thiols and Photodemethylationmentioning

confidence: 99%

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Photodemethylation of Methylmercury in Eastern Canadian Arctic Thaw Pond and Lake Ecosystems

Girard

Leclerc

Amyot

2016

Environ. Sci. Technol.

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“…These were then left to equilibrate overnight prior to analysis. The addition of SA in excess prior to the addition of Cu(II) minimized the risk of oxidizing natural thiols by the Cu(II) added during titrations as it kept the concentration of Cu 2+ low (Moingt et al, 2010). Similarly, we kept samples in the dark when not in use and equilibrated titrations overnight to minimize exposure to light and reduce the risk of photooxidation (Laglera and van den Berg, 2006).…”

Section: Complexing Capacity Titrationsmentioning

confidence: 99%

“…The voltammetric peak measured for this type of species is that of mercury-bound sulfide (Hg-thiol), and is not due to the reduction of copper stabilized as a copperbound thiol as for glutathione (Le Gall and van den Berg, 1993) or cysteine (van den Berg et al, 1988), which occur at more positive potentials and have a broader peak appearance. Measurements of the natural thiols were therefore made without any addition of Cu(II), eliminating the risk of thiol oxidation by added Cu(II) (Moingt et al, 2010).…”

Section: Identifying Csv Peaksmentioning

confidence: 99%