 |
| Titel |
How relevant is the deposition of mercury onto snowpacks? – Part 1: A statistical study on the impact of environmental factors |
| VerfasserIn |
D. A. Durnford, A. P. Dastoor, A. O. Steen, T. Berg, A. Ryzhkov, D. Figueras-Nieto, L. R. Hole, K. A. Pfaffhuber, H. Hung |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 19 ; Nr. 12, no. 19 (2012-10-11), S.9221-9249 |
| Datensatznummer |
250011503
|
| Publikation (Nr.) |
 copernicus.org/acp-12-9221-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| A portion of the highly toxic methylmercury that bioaccumulates in aquatic
life is created from mercury entering bodies of water with snowpack
meltwater. To determine the importance of meltwater as a source of aquatic
mercury, it is necessary to understand the environmental processes that
govern the behavior of snowpack-related mercury. In this study we investigate
relationships among 5 types of snowpack-related mercury observations and 20
model environmental variables. The observation types are the 24-h fractional
loss of mercury from surface snow, and the concentrations of mercury in
surface snow, seasonal snowpacks, the snowpack meltwater's ionic pulse, and
long-term snowpack-related records. The model environmental variables include
those related to atmospheric mercury, insolation, wind, atmospheric
stability, snowpack physical characteristics, atmospheric pressure, and solid
precipitation. Bivariate and multiple linear regressions were performed twice
for each mercury observation type: once with all observations, and once
excluding observations from locations where the snowpack's burden of
oxidizing and stabilizing halogens is known or presumed to affect snowpack
mercury. Since no observations from long-term snowpack-related records were
considered affected by halogens, this group of observations was included with
the sets of uninfluenced observations and was not discussed with the
complete, original sets of observations. When all observations are included,
only 37% of their variability can be explained, on average, with
significance confidence levels averaging 81%; a separate regression model
predicts each mercury observation type. Without the influence of halogens,
the regression models are able to explain an average of 79% of the
observations' variability with significance confidence levels averaging
97%. The snowpack-related mercury observations are most strongly
controlled by the dry and wet depositions of oxidized mercury, and by
precipitation. Mercury deposited through wet processes is more strongly
retained by snowpacks than mercury deposited through dry processes.
Revolatilization of mercury deposited through wet processes may be inhibited
through burial by fresh snowfalls and/or by its more central location,
compared to that of mercury deposited through dry deposition, within snowpack
snow grains. The two depositions of oxidized mercury together explain
84% of the variability in observed concentrations of mercury in surface
snow, 52% of the variability of observed concentrations of mercury in
seasonal snowpacks and their meltwater's ionic pulse, and only 20% of
the variability of observed concentrations of mercury in long-term
snowpack-related records; other environmental controls seemingly gain in
relevance as time passes. The concentration of mercury in long-term records
is apparently primarily affected by latitude; both the primary sources of
anthropogenic mercury and the strong upper-level zonal winds are located in
the midlatitudes. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|