title: Widespread natural perchlorate in unsaturated zones of the southwest United States.
abstract: 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.
authors: Department of Civil and Environmental Engineering, Texas Tech University, Lubbock, Texas 79409-1023, USA.
authors: Balaji
authors: B
authors: Rao
authors: Todd A
authors: TA
authors: Anderson
authors: Greta J
authors: GJ
authors: Orris
authors: Ken A
authors: KA
authors: Rainwater
authors: Srinath
authors: S
authors: Rajagopalan
authors: Renee M
authors: RM
authors: Sandvig
authors: Bridget R
authors: BR
authors: Scanlon
authors: David A
authors: DA
authors: Stonestrom
authors: Michelle A
authors: MA
authors: Walvoord
authors: W Andrew
authors: WA
authors: Jackson
mesh_terms: D019015:Geologic Sediments / Q000737:chemistry; D010472:Perchlorates / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D015206:Southwestern United States
chemical_list: D010472:Perchlorates; D012989:Soil Pollutants