Discovery of natural perchlorate in the Antarctic Dry Valleys and its global implications.
In the past few years, it has become increasingly apparent that perchlorate (ClO(4)(-)) is present on all continents, except the polar regions where it had not yet been assessed, and that it may have a significant natural source. Here, we report on the discovery of perchlorate in soil and ice from several Antarctic Dry Valleys (ADVs) where concentrations reach up to 1100 microg/kg. In the driest ADV, perchlorate correlates with atmospherically deposited nitrate. Far from anthropogenic activity, ADV perchlorate provides unambiguous evidence that natural perchlorate is ubiquitous on Earth. The discovery has significant implications for the origin of perchlorate, its global biogeochemical interactions, and possible interactions with the polar ice sheets. The results support the hypotheses that perchlorate is produced globally and continuously in the Earth's atmosphere, that it typically accumulates in hyperarid areas, and that it does not build up in oceans or other wet environments most likely because of microbial reduction on a global scale.
Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA. samuel.kounaves@tufts.edu
Samuel P
SP
Kounaves
Shannon T
ST
Stroble
Rachel M
RM
Anderson
Quincy
Q
Moore
David C
DC
Catling
Susanne
S
Douglas
Christopher P
CP
McKay
Douglas W
DW
Ming
Peter H
PH
Smith
Leslie K
LK
Tamppari
Aaron P
AP
Zent
D000864:Antarctic Regions; D002712:Chlorides / Q000032:analysis; D017753:Ecosystem; D007053:Ice; D009566:Nitrates / Q000032:analysis; D010472:Perchlorates / Q000032:analysis*; D012987:Soil / Q000032:analysis
D002712:Chlorides; D007053:Ice; D009566:Nitrates; D010472:Perchlorates; D012987:Soil; C494474:perchlorate