Widespread natural perchlorate in unsaturated zones of the southwest United States.
A substantial reservoir (up to 1 kg ha(-1)) of natural perchlorate is present in diverse unsaturated zones of the arid and semi-arid southwestern United States. The perchlorate co-occurs with meteoric chloride that has accumulated in these soils throughout the Holocene [0 to 10-15 ka (thousand years ago)] and possibly longer periods. Previously, natural perchlorate widely believed to be limited to the Atacama Desert, now appears widespread in steppe-to-desert ecoregions. The perchlorate reservoir becomes sufficiently large to affect groundwater when recharge from irrigation or climate change flushes accumulated salts from the unsaturated zone. This new source may help explain increasing reports of perchlorate in dry region agricultural products and should be considered when evaluating overall source contributions.
Rao
Balaji
B
Department of Civil and Environmental Engineering, Texas Tech University, Lubbock, Texas 79409-1023, USA.
Anderson
Todd A
TA
Orris
Greta J
GJ
Rainwater
Ken A
KA
Rajagopalan
Srinath
S
Sandvig
Renee M
RM
Scanlon
Bridget R
BR
Stonestrom
David A
DA
Walvoord
Michelle A
MA
Jackson
W Andrew
WA
D019015:Geologic Sediments / Q000737:chemistry; D010472:Perchlorates / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D015206:Southwestern United States
D010472:Perchlorates; D012989:Soil Pollutants