Dynamic leaching and fractionation of trace elements from environmental solids exploiting a novel circulating-flow...

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Geochemistry

Background:

• Bioaccessibility testing of trace elements in sediments is crucial for environmental risk assessment.
• Conventional methods are often time-consuming and labor-intensive.
• Simplifying these tests can improve efficiency and data throughput.

Purpose of the Study:

• To develop a novel, simplified analytical approach for trace element bioaccessibility testing in sediments.
• To introduce a dynamic flow-through microcolumn extraction system with extractant re-circulation.
• To validate the on-line all injection (AI) analysis for determining metal bioaccessible pools.

Main Methods:

• Development of a dynamic flow-through microcolumn extraction system.
• Utilizing on-line all injection (AI) analysis for metal leaching under steady-state conditions.
• Application of Tessier's sequential extraction scheme and single acid extraction.
• Validation using Certified Reference Materials (CRM) and real sediment samples.

Main Results:

• The on-line AI method significantly reduced extraction time (e.g., Tessier's test in 6h vs. >17h).
• Improved analytical precision was achieved (<9.2% vs. >15% for conventional methods).
• A notable decrease in blank readouts was observed compared to manual batch methods.

Conclusions:

• The proposed dynamic flow-through microcolumn system offers a simplified and efficient approach for bioaccessibility testing.
• The on-line AI method provides a faster, more precise, and less prone to blank errors alternative to conventional techniques.
• This method is suitable for determining maximum bioaccessible pools of trace metals (Cu, Zn, Cd, Pb) in various sediment types.