[Stabilization and long-term effect of chromium contaminated soil]

Area of Science:

• Environmental Science
• Soil Science
• Geochemistry

Background:

• Chromium (Cr) contamination poses significant risks to soil and ecosystems.
• Effective stabilization methods are crucial for managing Cr-polluted sites.

Purpose of the Study:

• To evaluate the short-term and long-term stabilization effects of four amendments on Cr-contaminated soil.
• To identify the most effective amendments for reducing chromium leaching and mobility.

Main Methods:

• Nature curing of Cr-contaminated soil with ferrous sulfide, ferrous sulfate, zero-valent iron, and sodium dithionite.
• Analysis of total leaching Cr and Cr(VI) content over 3 days, 28 days, and 1 year.
• Monitoring of soil pH to assess amendment suitability.

Main Results:

• Ferrous sulfide and zero-valent iron showed limited stabilization due to poor solubility and immobility.
• Ferrous sulfate demonstrated rapid and effective reduction of total leaching Cr and Cr(VI).
• Long-term curing with ferrous sulfate promoted stabilization through iron hydroxide generation; sodium dithionite also showed positive effects, maintaining soil pH between 6-8.

Conclusions:

• Ferrous sulfate is a highly effective amendment for Cr-contaminated soil stabilization, with benefits increasing over time.
• Sodium dithionite is also beneficial, particularly for maintaining a favorable soil pH range for stabilization.
• Ferrous sulfide and zero-valent iron are less suitable for direct application in Cr stabilization due to their physical properties.