38 research outputs found
Behavior of mercury in snow from different latitudes
Deposition of Hg via snow fall may represent an important Hg flux to terrestrial and
aquatic ecosystem of temperate and polar regions. We have conducted a series of field and
laboratory experiments to better understand the post-depositional behaviour of Hg in snow.
We found that: 1) a significant portion of the snow-to-air Hg evasion results from
photoreduction of Hg in snow; 2) this photoreduction is mainly driven by UV-B radiation; 3)
this photoreduction can be observed even in the presence of halogens in the snow, although we
further found that these halogens favour the reverse photooxidation reaction; 4) laboratory
experiments show that this photoreduction is likely mediated by organic reducing agents found
in the snow matrix. These data will be incorporated in a global/regional Hg model. We
propose that Hg falling inland in temperate and Arctic areas could be more rapidly re-emitted
than Hg falling in coastal Arctic areas (where mercury depletion events occur)