Migration and accumulation of antimony and arsenic in a wetland incharged by wastewater from a Sb tailing pond, southwest China

Zengping Ninga, H. Y. Chena,c, Q. X. Xiaoa,c, E. Z. Xiaob, X. L. Lana,b, L. Maa,c, Y. Z. Liua, and T. F. Xiaob*

a State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang ,China

b Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou,China

c University of Chinese Academy of Sciences, Beijing, China

ningzengping@mail.gyig.ac.cn

Antimony and its compounds have been emerging global contaminants due to their toxicity, transportation and wild use. The mining industry is one of the most important sources of Sb, which could cause increasingly accumulation of that Sb and other toxic metals in supergene environment, such as soil and water. In the past 20 years, numerous studies focused on the environmental geochemistry of Sb and its environmental risk, but researches on the transportation and accumulation of Sb between sediments and aquatic plants are still rare. Interestingly, we have found that Typha latifolia Linn. can survive in a wetland seriously contaminated by discharges from a tailing pond of a large Sb smelting factory, southwest China. However, there is little information on why Typha latifolia Linn. can live in such wicked environment with high Sb concentrations, and whether it can uptake Sb or not. In order to investigate the distribution of Sb and As in the wetland, and ascertain the tolerance and/or accumulation of Sb by Typha latifolia Linn., eighteen sediments (including nine surface and nine rhizosphere sediments) and nine Typha latifolia Linn. samples were collected, and the concentrations of Sb and As in all samples were analysed by ICPMS. The results showed that the concentrations of Sb and As in sediments were 743.7 ± 327.0 mg/kg and 24.4 ± 11.6 mg/kg, respectively, suggesting that the sediments in the wetland were seriously polluted by wastewater discharged from the tailing pond of the large Sb smelting factory. Compared to surface sediments (669.6 ± 228.8mg/kg Sb and 21.3 ± 4.70 mg/kg As), the rhizosphere sediments were much more enriched in Sb (817.9 ± 403.1mg/kg) and As (27.5 ± 15.6 mg/kg ), which may infer that the root exudates of Typha latifolia Linn. could be helpful for bounding Sb and As around its rhizosphere. Typha latifolia Linn. can uptake large amounts of Sb and As, although our previous research had documented that the bioavailabilities of Sb and As in tailings were quite low. Specially, Sb concentration was up to 300.0 mg/kg, suggesting that Typha latifolia Linn. has the characteristics of tolerating and accumulating high Sb concentration. In all, this study had confirmed that the wastewater from the Sb tailing pond had polluted the adjacent aquatic environment, and Typha latifolia Linn. is a Sb-tolerant and Sb-accumulate specie, which has great potential for bioremediation of Sb polluted aquatic environment in future.

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