Improving trace element measurement accuracy: Lysimeter cleaning and material effects

Area of Science:

• Environmental Science
• Soil Science
• Analytical Chemistry

Background:

• Lysimeters are crucial for soil solution collection, but material interactions can introduce trace element (TE) errors.
• Accurate TE analysis requires minimizing lysimeter-induced contamination.

Purpose of the Study:

• To develop and evaluate optimized cleaning protocols for common tension lysimeters.
• To assess the trace element sorption and release characteristics of Rhizon MOM, SPE20 nylon, and SiC20 lysimeters.

Main Methods:

• Lysimeters underwent sequential rinsing with acids and ultrapure water (UPW), followed by UPW soaking and sonication.
• Sorption and release of TEs were evaluated using soil leachate before and after cleaning.
• TE concentrations in lysimeter blanks were analyzed using standard laboratory techniques.

Main Results:

• Optimized cleaning rapidly reduced residual TEs in Rhizon and nylon lysimeters.
• Rhizon and nylon lysimeters, post-cleaning, showed low TE blanks (1-100 ng L⁻¹), with exceptions for Al, Fe, Zn, Tl, and Th.
• SiC lysimeters released high concentrations of multiple TEs (e.g., Al, V, Fe, Ni, Zn, Sr >1 µg L⁻¹) and exhibited significant sorption/release for many TEs.

Conclusions:

• Effective cleaning protocols are vital for accurate TE analysis with Rhizon and nylon lysimeters.
• SiC lysimeters are unsuitable for studies requiring low TE detection limits due to inherent release issues.
• Researchers must select lysimeters and cleaning methods based on specific research objectives and required detection limits.