Evaluation of phytoremediation potential of five Cd (hyper)accumulators in two Cd contaminated soils

Rong Huang; Meiliang Dong; Peng Mao; Ping Zhuang; Jorge Paz-Ferreiro; Yongxing Li; Yingwen Li; Xiaoying Hu; Pacian Netherway; Zhian Li

doi:10.1016/j.scitotenv.2020.137581

Evaluation of phytoremediation potential of five Cd (hyper)accumulators in two Cd contaminated soils

Sci Total Environ. 2020 Jun 15:721:137581. doi: 10.1016/j.scitotenv.2020.137581. Epub 2020 Feb 25.

Authors

Affiliations

¹ Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
³ School of Engineering, RMIT University, Melbourne 3000, Australia. Electronic address: jorge.paz-ferreiro@rmit.edu.au.
⁴ School of Engineering, RMIT University, Melbourne 3000, Australia.
⁵ Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458B, China. Electronic address: lizan@scbg.ac.cn.

PMID: 32163732
DOI: 10.1016/j.scitotenv.2020.137581

Abstract

A phytoextraction experiment with five Cd hyperaccumulators (Amaranthus hypochondriacus, Celosia argentea, Solanum nigrum, Phytolacca acinosa and Sedum plumbizincicola) was conducted in two soils with different soil pH (5.93 and 7.43, respectively). Most accumulator plants grew better in the acidic soil, with 19.59-39.63% higher biomass than in the alkaline soil, except for S. plumbizincicola. The potential for a metal-contaminated soil to be cleaned up using phytoremediation is determined by the metal uptake capacity of hyperaccumulator, soil properties, and mutual fitness of plant-soil relationships. In the acidic soil, C. argentea and A. hypochondriacus extracted the highest amount of Cd (1.03 mg pot^-1 and 0.92 mg pot^-1, respectively). In the alkaline soil, S. plumbizincicola performed best, mainly as a result of high Cd accumulation in plant tissue (541.36 mg kg^-1). Most plants achieved leaf Cd bioconcentration factor (BCF) of >10 in the acidic soil, compared to <4 in the alkaline soil. Soil Cd availability was chiefly responsible for such contrasting metal extraction capacity, with 5.02% fraction and 48.50% fraction of total Cd being available in the alkaline and acidic soil, respectively. In the alkaline soil, plants tended to increase rhizosphere soil available Cd mainly through excreting more low molecular weight organic acids, not through changing the soil pH. In the acidic soil, plants slightly decreased soil available Cd. Those species which have high Ca, Zn, Fe uptake capacity extract more Cd from soil, and a positive correlation was found between the concentrations of Cd and Ca, Zn, Fe in leaves. Soil available Ca²⁺, Mg²⁺, SO₄^2-, Cl^- did not play a key role in Cd uptake by plants. In summary, acidic soil was of higher potential to recover from Cd contamination by phytoextraction, while in the alkaline soil, S. plumbizincicola showed potential for Cd phytoextraction.

Keywords: Acidic soil; Alkaline soil; Cadmium availability; Hyperaccumulator; Phytoextraction.

MeSH terms

Biodegradation, Environmental
Cadmium / analysis
Sedum*
Soil
Soil Pollutants / analysis*

Substances

Soil
Soil Pollutants
Cadmium