Bioaccumulation, transfer characteristics of metals in six vascular plants, and soil pollution assessment from Wachangping karst bauxite residue areas

Abstract

Bauxite residue (BR) is a large volume by-product generated during bauxite smelting process and metal pollution problem is becoming increasingly prominent in residue areas. Accumulation and transfer of metals in six vascular plants were analyzed and soil environment was evaluated. Results found levels of Al (2,110–26,280 mg kg⁻¹), Fe (990 to 9,880 mg kg⁻¹), Ca (8,020 to 49,250 mg kg⁻¹), Mg (2,060 to 17,190 mg kg⁻¹), K (16,840 to 39,670 mg kg⁻¹), and Ti (80 to 1,240 mg kg⁻¹) in plants. Metal concentrations in soils exceeded background levels. Bioconcentration factor (BCF) found that Al, Fe, and Ti in plants (roots, stems, and leaves) were relatively depleted (BCF <1). Transfer factor (TF) of Al, Fe, Ca, K, and Ti in plants was distinctly higher than 1 and mainly concentrated in stems and leaves. Pollution indices revealed that soil environment was at moderated to serious contaminated risk. Principal components analysis (PCA) showed that Artemisia caruifolia Buch. and Siegesbeckia orientalis L. plants had a good ability to absorb Al and Fe, which can be used as biological indicators and restoration materials.

NOVELTY STATEMENT

• Currently, soil environment was exposed to moderated to serious contaminated risk from Wachangping karst bauxite residue areas.

• Bioconcentration factor (BCF) analysis found that Al, Fe, and Ti in six vascular plants (roots, stems, and leaves) were relatively depleted (BCF <1).

• Transfer factor (TF) of Al, Fe, Ca, K, and Ti in vascular plants was distinctly higher than 1, which mainly concentrated in stems and leaves.

• PCA revealed that Artemisia caruifolia Buch. and Siegesbeckia orientalis L. plants had a good ability to absorb Al and Fe, which can be used as biological indicators and ecological restoration materials.

Keywords:

• Bauxite residue areas (BRAS)
• bioaccumulation
• metals
• soil pollution assessment
• vascular plants

Acknowledgments

The authors would like to thank Shen Jiachen and Li Chengyi for technical assistance and Xu Sheng and Ding Haifeng for help with fieldwork.

Disclosure statement

No conflict of interest exists in the submission of this manuscript, and manuscript is approved by all authors for publication. There are no financial competing interests.

Additional information

Funding

This project was funded by the National Natural Science Foundation of China (NSFC Nos. 32360309 and 31960044).