Copper lability in soils subjected to intermittent submergence

Area of Science:

• Soil Science
• Environmental Chemistry
• Geochemistry

Background:

• Soil redox conditions significantly impact metal availability, influencing nutrient and toxic metal mobility.
• Literature presents conflicting findings regarding the effects of temporary waterlogging on metal availability in soils.
• Understanding metal remobilization under fluctuating redox conditions is crucial for environmental risk assessment.

Purpose of the Study:

• To investigate the impact of intermittent soil submergence on the labile pool of copper (Cu) in Oxisol and Inceptisol soils.
• To quantify changes in copper lability using isotopic dilution techniques following up to three submergence cycles.
• To assess the influence of different copper sources (biosolids-Cu and salt-Cu) and submergence frequency on copper availability.

Main Methods:

• Utilized isotopic dilution techniques to measure changes in the labile copper pool.
• Applied intermittent soil submergence cycles (up to three) to field-amended Oxisol and Inceptisol soils.
• Amended soils with both biosolids-derived copper and salt-derived copper to evaluate different sources.

Main Results:

• Intermittent soil submergence significantly increased the lability of copper in both soil types across all treatments.
• Copper lability, indicated by E(total) values, generally increased with successive submergence cycles.
• The highest increase in copper lability was observed in soils treated with salt-Cu, suggesting a greater impact of this source.

Conclusions:

• Intermittent waterlogging enhances the availability of copper in soils, with implications for metal mobility and potential uptake.
• The effect of submergence on copper lability is dependent on the soil type and the source of copper amendment.
• The formation of nonexchangeable colloidal copper forms is influenced by soil treatments and submergence cycles, highlighting complex metal-soil interactions.