Ectomycorrhizal Fungal Inoculation of Sphaerosporella brunnea Significantly Increased Stem Biomass of Salix miyabeana and Decreased Lead, Tin, and Zinc, Soil Concentrations during the Phytoremediation of an Industrial Landfill.

Dimitri J Dagher,Frédéric E Pitre,Mohamed Hijri

doi:10.3390/jof6020087

Abstract

Fast growing, high biomass willows (Salix sp.) have been extensively used for the phytoremediation of trace element-contaminated environments, as they have an extensive root system and they tolerate abiotic stressors such as drought and metal toxicity. Being dual mycorrhizal plants, they can engage single or simultaneous symbiotic associations with both arbuscular mycorrhizal (AM) fungi and ectomycorrhizal (EM) fungi, which can improve overall plant health and growth. The aim of this study was to test the effect of these mycorrhizal fungi on the growth and trace element (TE) extraction potential of willows. A field experiment was carried out where we grew Salix miyabeana clone SX67 on the site of a decommissioned industrial landfill, and inoculated the shrubs with an AM fungus Rhizophagus irregularis, an EM fungus Sphaerosporella brunnea, or a mixture of both. After two growing seasons, the willows inoculated with the EM fungus S. brunnea produced significantly higher biomass. Ba, Cd and Zn were found to be phytoextracted to the aerial plant biomass, where Cd presented the highest bioconcentration factor values in all treatments. Additionally, the plots where the willows received the S. brunnea inoculation showed a significant decrease of Cu, Pb, and Sn soil concentrations. AM fungi inoculation and dual inoculation did not significantly influence biomass production and soil TE levels.

Highlights

With the surge of the human population and urban development in the past century, modern society has been generating an ever-increasing amount of industrial waste
Survival rate of Salix spp. clones in phytoremediation applications depends on many parameters such as pollution concentrations, climate, contamination depth, etc
Tested two Salix clones SX64 and SX67 to remedy a deep, polluted plume contaminated by petroleum hydrocarbons and obtained a survival rate as low as 24.4% for S. miyabeana clone SX67, which resulted in the failure of that phytoremediation assay [34]

Summary

Introduction

With the surge of the human population and urban development in the past century, modern society has been generating an ever-increasing amount of industrial waste. Industrial residues and by-products are buried in the ground around urban centers, creating vast landfills, most often composed of non-organic waste such as glass, plastics, and trace elements (TE) such as lead. TE are solubilized and leech into the environment, resulting in elevated levels in soil and water [1,2]. Because they are not degradable, they accumulate in the ecosystems and pose a serious environmental and human health risk [3,4].

Objectives

Methods

Results