Is the Arctic a missing sink for
mercury?:
New measurements of mercury speciation and depletion events at Point
Barrow
Steve Lindberg
Oak Ridge National Laboratory
and
Steve Brooks
NOAA / Air Resources Laboratory
In the past decade many
new sources of diffuse mercury emissions have been measured. These
sources significantly increase the estimates of global mercury emissions,
and suggest there may be missing mercury sinks in global models.
Mercury levels in Arctic wildlife are elevated above normal levels,
but there are few known Arctic mercury sources, and long range transport
of mercury must be considered. The discovery of mercury depletion
events (MDE, similar to ozone depletion) at Alert, NWT suggests
a mechanism for mercury accumulation from the global pool. One hypothesis
is that mercury is transformed into a reactive gaseous mercury (RGM)
species which deposits locally. This species has never been measured
in the Arctic, and MDE's must be confirmed at other Arctic sites.