A multi-surface model to predict Cd phytoavailability to wheat (Triticum aestivum L.).

Area of Science:

• Environmental Chemistry
• Soil Science
• Geochemistry

Background:

• Metal bioavailability in soils is crucial for risk assessment.
• Dissolved metal concentration is a key determinant of bioavailability.
• Geochemical multi-surface models (MSMs) are emerging tools for metal partitioning analysis.

Purpose of the Study:

• To assess cadmium (Cd) bioavailability in wheat using a geochemical multi-surface model (MSM).
• To compare the efficacy of MSM predictions against traditional chemical extraction methods.
• To evaluate the utility of MSM for soil Cd risk assessment.

Main Methods:

• A geochemical multi-surface model (MSM) with generic parameters was employed.
• The model was validated using wheat (Triticum aestivum L.) grown in 12 diverse soils.
• Model performance was compared with CaCl2, HNO3 extraction, and total soil Cd analysis.
• The MSM was further tested on 84 field-collected wheat-soil samples.

Main Results:

• MSM-calculated dissolved Cd showed strong correlations with Cd uptake in wheat roots (R²=0.873) and shoots (R²=0.837).
• The MSM outperformed chemical extraction methods in predicting Cd bioavailability.
• MSM-predicted Cd in wheat seeds correlated better with actual seed Cd than extraction methods.
• Optimized calculation conditions considered soil organic matter, soil/solution ratio, and background cations.

Conclusions:

• MSM-calculated dissolved Cd is a reliable indicator of Cd bioavailability in soils.
• The MSM provides a valuable tool for assessing the risk of Cd contamination in agricultural soils.
• This modeling approach offers a more accurate alternative to conventional chemical extraction techniques.