U.S. Department of Defense


Date of this Version



Environmental Pollution 184, 2014


U.S. Government work


Perchlorate (ClO4-) interferes with uptake of iodide in humans. Emission inventories do not explain observed distributions. Ozone (O3) is implicated in the natural origin of ClO4-, and has increased since preindustrial times. O3 produces ClO4 - in vitro from Cl -, and plant tissues contain Cl- and redox reactions.We hypothesize that O3 exposure may induce plant synthesis of ClO4-.We exposed contrasting crop species to environmentally relevant O3 concentrations. In the absence of O3 exposure, species exhibited a large range of ClO4- accumulation but there was no relationship between leaf ClO4- and O3, whether expressed as exposure or cumulative flux (dose). Older, senescing leaves accumulated more ClO4- than younger leaves. O3 exposed vegetation is not a source of environmental ClO4 -. There was evidence of enhanced ClO4 - content in the soil surface at the highest O3 exposure, which could be a significant contributor to environmental ClO4-.