High ozone increases soil perchlorate but does not affect foliar perchlorate content

Area of Science:

• Environmental Chemistry
• Plant Physiology
• Atmospheric Science

Background:

• Ozone (O) is a pollutant linked to environmental chloride (ClO) formation.
• Elevated tropospheric O is observed globally, impacting ecosystems.
• Previous research indicated near-ambient O did not increase foliar ClO.

Purpose of the Study:

• To investigate the impact of high ozone concentrations on foliar and soil chloride (ClO) levels.
• To determine if ozone exposure increases foliar ClO, contributing to environmental ClO.
• To assess the relationship between ozone exposure, plant uptake, and ClO accumulation.

Main Methods:

• Controlled exposure of vegetation to high ozone concentrations (up to 204 nL/L).
• Measurement of foliar and soil surface ClO concentrations.
• Analysis of ClO accumulation in relation to ozone exposure and stomatal uptake.

Main Results:

• High ozone concentrations significantly increased soil surface ClO linearly with ozone levels.
• No correlation was found between ozone exposure/uptake and increased foliar ClO.
• ClO accumulation varied by plant species but was not linked to soil or foliar ClO post-ozone exposure.

Conclusions:

• Tropospheric ozone contributes to environmental ClO primarily through soil interactions.
• Ozone does not appear to increase foliar ClO, even at high concentrations.
• The study extends findings to high ozone levels, clarifying ozone's role in environmental ClO cycling.