Effects of four woody plant species revegetation on habitat improvement and the spatial distribution of arsenic and antimony in zinc smelting slag

Abstract

Broussonetia papyrifera, Cryptomeria fortunei, Arundo donax, and Robinia pseudoacacia were planted on a zinc smelting slag site. The habitat conditions and spatial distribution of arsenic (As) and antimony (Sb) in slag were analyzed after seven years of restoration. The results showed that the pH, conductivity (EC), and moisture content of phytoremediated slag were lower than those of the control slag. The redox potential (Eh) and EC decreased with increasing slag depth. Phytostabilization significantly increased the contents of total nitrogen (TN), total phosphorus (TP), available nitrogen (AN), available phosphorus (AP), and dissolved organic carbon (DOC) in slag. TN, AN, AP, and DOC in slag showed obvious surface polymerization. Phytostabilization increased the content of calcite and gypsum in the slag. As and Sb concentrations were significantly lower than control slag, with an average decrease of 651–844 and 422–693 mg·kg ⁻¹, respectively. Residual As and Sb in phytoremediated slag was the most present form, the proportion of which was higher than that in the control slag. The proportions of calcium-bound and aluminum-bound As and Sb were lower. The contents of arsenic and antimony in plants had lower levels and followed the order of roots > leaves > stems. As and Sb showed a strong positive correlation with pH, EC, moisture content, and a negative correlation with TN, TP, AN, AP, and DOC. In summary, phytostabilization significantly improved slag site conditions and reduce As and Sb available concentrations.

Novelty statement Co-contamination of As and Sb is common in mining areas because of similar chemical properties. There are only few reports on the effects of matrix modification and phytoremediation (without additional soil cover) on the soil physicochemical properties, the spatial distribution, and the bioavailability of As and Sb in zinc slag with an alkaline pH. The research determined that phytostabilization significantly improved slag site conditions and reduce As and Sb available concentrations. The results obtained can be used as necessary information for the large-scale ecological restoration or vegetation reconstruction of zinc smelting slag yards.

Keywords:

• Zinc smelting slag
• phytostabilization
• nutrients
• As
• Sb
• distribution

Disclosure statement

No conflict of interest was reported by the author(s).

Author contributions

Hang Sun: designed the study, performed the experiments, and original draft preparation.

Xinlong Li: carried out a portion of the experiments.

Yonggui Wu: writing, reviewing, and editing.

Additional information

Funding

This study was funded by grants from the United Fund of Guizhou Province Government, the National Natural Science Foundation of China [U1612442], the National Natural Science Foundation of China [41663009], and the First-Class Ecology Discipline in Guizhou Province [GNYL[2017]007].