Evasion of mercury from peatlands: A significant factor in the recovery of boreal fish from mercury pollution?

Last changed: 02 May 2022

The project 'Evasion of mercury from peatlands: A significant factor in the recovery of boreal fish from mercury pollution?' started in 2010 and ended 2013.

International efforts to alleviate this problem are focused on reducing Hg deposition. However, it seems doubtful that these efforts will lessen the burden on Swedish fish, since so much Hg has already accumulated in the superficial organic soils of peatlands. But Hg can evade as a gas. Without knowing the land-atmosphere exchange of Hg from peatlands we cannot predict how effective efforts to cut Hg emissions will be in achieving a timely reduction in the pool of Hg in these peatlands and ultimately the loading of MeHg from peatlands to surface waters.

In this first study we intended to define the land-atmosphere exchange from a boreal mire. We aimed to test the hypothesis that current estimates of the time it will take for reduced Hg emissions to translate into lower Hg levels in boreal fish are far too long because the exchange of Hg between the peat surface and the atmosphere has been ignored. This test will be made by

I) The first quantification of seasonal land-atmosphere exchange of Hg over a boreal peatland

II) The first long term application of the relaxed eddy accumulation technique for Hg

III) Defining the influence of warming and changed moisture regimes, as well atmospheric pollutants on Hg evasion to the atmosphere from a peatland.

International efforts to alleviate Hg pollution in fish are focused on reducing Hg deposition. However, it seems doubtful that these efforts will lessen the burden on Swedish fish, since so much Hg has already accumulated in the superficial organic soils of peatlands. But Hg can evade as a gas.

The project was financed by Svenska Vetenskapsrådet. The budget was 3 MSEK.

Participating from the Department was Kevin Bishop..

External partner was Basel University.