The effect of heavy metal stabilizers in arsenic-contaminated soil: using bioavailability

Abstract

Crops grown in arsenic-contaminated soil can negatively impact human health and ecosystems due to the transfer of arsenic. Therefore, it is essential to implement chemical stabilization to reduce bioavailability. This study aims to evaluate the effectiveness of stabilizers in reducing bioavailability. The stabilizers used were Fe(iron)–steel slag and Ecosta-A, a mixture of oyster shell and layer-double hydroxide(LDH). Phytoavailability and bioconcentration factor (BCF) were selected for evaluation of bioavailability. The study involved three conditions: A (stabilizer-free), B (Fe–steel slag treatment), and C (Ecosta-A treatment). Pots measuring 3 m × 3 m × 1 m were filled with arsenic-contaminated soil, and the stabilizers were mixed at a 5% ratio to the soil content and cured for about 18 months. Allium fistulosum L. (Welsh onions), Eruca vesicaria (Lettuce), and Zea mays L. (Corn) were then planted and grown for about 1–2 months. The phytoavailability test showed that arsenic content in the soil decreased by 97.06% in Condition C compared to Condition A, while it increased by 55.60% in Condition B. The BCF was calculated based on USEPA standards. BCF values were exceeded in the roots of plants under all conditions, and no translocation was observed in the edible parts of plants grown under conditions B and C. Therefore, this study demonstrates that evaluate phytoavailability and BCF is important for confirming the effect of stabilizers in reducing bioavailability. The results suggest that the Ecosta-A stabilizer is more effective in this regard.