Hydroponic Phytoremediation of Ni, Co, and Pb by Iris Sibirica L.

Shuming Wan,Yiwei Li,Jun Pang,Ming Chang,Jinsheng Wang,Yanping Li,Lei Wang,Jia Zhu

doi:10.3390/su13169400

Abstract

Heavy metal pollution in mine wastelands is quite severe. Iris sibirica L., an emergent wetland plant, is characterized by an ability to survive under high stress of heavy metals. This study aimed to explore the phytoremediation ability of nickel (Ni), cobalt (Co), and lead (Pb) by Iris sibirica L. under hydroponic conditions. A series of tests were conducted at different metal stress conditions to evaluate the phytoextraction and tolerance of Iris sibirica L. The concentrations of Ni, Co, and Pb in plant shoots reached their highest values in 500 mg L−1 treatments, where they were 6.55%, 23.64%, and 79.24% higher than those in 300 mg L−1, respectively. The same concentrations in roots also reached their peak in 500 mg L−1 treatments, where they were 5.52%, 33.02%, and 70.15% higher than those in 300 mg L−1, respectively. Bioconcentration factors (BCF) for Ni, Co, and Pb revealed the phytoextraction ability of Iris sibirica L., and the translocation factors (TCF) showed that Ni may be most easily translocated in the plant, followed by Co and Pb. This study indicates that, compared with Ni and Co, Iris sibirica L. is more suitable for the phytoremediation of Pb-contaminated metal mine wastelands.

Highlights

Heavy metal (HM) pollution in the soil has become a global problem
The basic ability of hyperaccumulators is their high tolerance to metal stress, indicating these plants’ ability to resist the adverse and toxic conditions induced by HMs
Under 50 to 500 mg L−1 of Ni, more severe symptoms and necrosis were observed in the whole plants after 21 days

Summary

Introduction

Heavy metal (HM) pollution in the soil has become a global problem. Akin to many other countries in the world, China is facing severe soil metal pollution due to the country’s fast development over the past few decades [1,2,3]. Mining is considered to be one of the most significant sources of HMs [4,5]. It is estimated that 1.5 million ha of wasteland have been generated by mining in China, and the area of polluted land is increasing at a rate of. Nickel (Ni), cobalt (Co), and lead (Pb) are often widely contained in metal mining [7]. Pb is one of the most toxic HMs at low concentrations; if its concentration exceeds

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