In situ phytoremediation of copper and cadmium in a co-contaminated soil and its biological and physical effects.

Lei Xu,Jiani Liang,Jianbiao Peng,Xiangyu Xing,Jing Zhou

doi:10.1039/c8ra07645f

Abstract

Phytoremediation is a potential cost-effective technology for remediating heavy metal-contaminated soils. This method was used to evaluate the biomass and accumulation of copper (Cu) and cadmium (Cd) of plant species grown in contaminated soil and their biological and physical effects on the soil. In co-contaminated soils with copper (Cu) and cadmium (Cd), a three-year field experiment was conducted by planting four plant species in the co-contaminated acidic soil treated with hydroxyapatite. The four species produced different amounts of biomass in this order: Pennisetum sp. > Elsholtzia splendens > Setaria lutescens > Sedum plumbizincicola. Over three growing seasons, the best accumulators of Cu and Cd were Elsholtzia splendens and Sedum plumbizincicola, respectively. Overall, Pennisetum sp. was the best species for Cu and Cd removal when biomass was considered. The four plant treatments could improve the content of >0.25 mm mechanically stable (DR0.25) and water-stable (WR0.25) aggregates and significantly improve the aggregate mean mass diameter (MWD) and the geometric mean diameter (GMD). The largest increase was with the treatment of Pennisetum sinese, while the fractal dimension (FD) of mechanically stable aggregates could be significantly reduced by the treatment of Pennisetum sp. Hydroxyapatite and phytoremediation could improve the soil enzyme activity, and Elsholtzia splendens had the best effect in this respect. This study will provide a better understanding of the remediation of heavy metal contaminated soil.

Highlights

Soil contamination, agricultural soil contamination, has become a severe environmental problem as it poses a grave threat to human health by entering food chains and to environmental safety by leaching into groundwater.[1]
The soil pH increased signi cantly from 4.24 to 5.17 when hydroxyapatite was added. This might be due to the high pH (8.40) of hydroxyapatite
This was consistent with Cui et al, who found that the soil pH could be improved from of the addition of hydroxyapatite.[28]

Summary

Introduction

Agricultural soil contamination, has become a severe environmental problem as it poses a grave threat to human health by entering food chains and to environmental safety by leaching into groundwater.[1] Cadmium is a non-essential element that can cause great harm to plants and animals at very low concentrations. E-mail: zhoujing@ issas.ac.cn; Tel: +86-13913387498 cHenan Key Laboratory of Ecological Security for Water Source Region of Mid-line of South-to-North Diversion Project, NanYang, 473061, China dCollege of Non-Major Foreign Language Teaching, Nanyang Normal University, 473061, Nanyang, China eSchool of Environment, Henan Normal University, Xinxiang, 453007, China fJiangxi Engineering Research Center of Eco-Remediation of Heavy Metal Pollution, Jiangxi Academy of Science, Nanchang, 330096, China elements enter the soil. In the process of copper smelting, copper but cadmium will enter the soil together, leading to some contaminated soils.[3]

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Methods

Results