Empirical models for estimating mercury flux from soils

Area of Science:

• Environmental Chemistry
• Soil Science
• Atmospheric Chemistry

Background:

• Mercury (Hg) exchange between soil and atmosphere is influenced by multiple environmental factors.
• Current models for soil Hg flux are often simplistic and neglect complex interactions between these factors.

Purpose of the Study:

• To investigate the individual and combined effects of temperature, light, and soil moisture on soil Hg flux.
• To develop improved empirical models for estimating soil Hg flux by incorporating synergistic interactions.

Main Methods:

• Utilized a two-level factorial experimental design within a gas exchange chamber (GEC).
• Measured Hg flux under varying conditions of irradiation, soil moisture, and air temperature.
• Developed and verified two empirical models using data from GEC experiments and dynamic flux chamber (DFC) measurements.

Main Results:

• Individual factors (irradiation, soil moisture, temperature) significantly enhanced Hg evasive flux (90-140%).
• Significant synergistic effects (20-30% enhancement) were observed for all two-factor interactions, particularly air temperature/soil moisture and air temperature/irradiation.
• Developed empirical models demonstrated high predictability (r ≈ 0.9) for estimating dry soil Hg flux.

Conclusions:

• Soil Hg flux is significantly influenced by individual and interactive effects of temperature, light, and soil moisture.
• Incorporating second-order interactions into models enhances the accuracy of soil Hg flux estimations.
• The developed empirical models provide a more reliable tool for predicting mercury flux from soils.