The Effect of Granular Activated Carbon and Biochar on the Availability of Cu and Zn to Hordeum sativum Distichum in Contaminated Soil.

Marina Burachevskaya,Leonid Perelomov,Aleksey Fedorenko,Vishnu Rajput,Sergey Kolesnikov,Svetlana Sushkova,Natalia Chernikova,Victor Chaplygin,Tatiana Minkina,Saglara Mandzhieva,Tatiana Bauer,Inna Zamulina

doi:10.3390/plants10050841

Abstract

The presence of heavy metals in the soil could impose serious problems on soil-plant systems due to the accumulation of heavy metals in plants. Even vital elements such as Cu and Zn have a toxic effect in the case of excessive intake by living organisms. The present work aimed to investigate the content of loosely bound (exchangeable, complexed, and specifically sorbed) compounds of Cu and Zn and their availability to spring barley (Hordeum sativum distichum) in contaminated Haplic Chernozem soil under the conditions of a model experiment (five approximate permissible concentrations (APC) and 10 APC of metal). Changes in the bioavailability of the metals upon application of carbon sorbents were observed. An increase in loosely bound metal compounds has been shown under conditions of soil contamination with metals (up to 57% of the total content). The increase in the availability of Cu in the soil was mainly due to the formation of complexed metal forms with organic matter (up to 17%). The availability of Zn was found to be associated with an increase in exchangeable (up to 21%) and specifically sorbed compounds (up to 27%). Granular activated carbon (GAC) and biochar have high sorption properties. A decrease in the content of loosely bound compounds of metals was established, especially in the most mobile forms such as exchangeable and complexed forms. The introduction of sorbents into the soil opened up a new venue for binding heavy metals in situ, eventually leading to a decrease in their bioavailability. The inactivation of Cu and Zn in the soil upon the application of sorbents led to a decrease in metal absorption by spring barley. The highest efficiency of biochar application was established at a dose of 2.5% and 5% in soil contaminations of 5 APC and 10 APC of Cu or Zn. The efficiency of the use of sorbents was more influenced by the dose of application than by the type of sorbent. There was no significant difference between biochar and GAC. Stabilization and inactivation of metals may improve soil fertility and plant growth.

Highlights

Soil contamination with various types of chemical compounds has been a growing concern in recent years
There was no significant difference between biochar and Granular activated carbon (GAC)
The share of loosely bound compounds of heavy metals (HMs) decreased with the introduction of carbon sorbents

Summary

Introduction

Soil contamination with various types of chemical compounds has been a growing concern in recent years. HM immobilization is the most common in situ remediation method for contaminated soils, and it is achieved by adding sorbents and/or ameliorating additives to allow HM stabilization, which leads to a decrease in their bioavailability in the soil This has found extensive application in advanced remediation technologies for the restoration and cleaning up of polluted sites [4]. The choice of sorbents should be based on their capacity to bind HM compounds strenuously, and on creating an ideal environment for plant growth and development. In this case, both the barrier functions of soils and plants can be increased to attain the optimal effect of their application. A wide range of materials are used as sorbents, i.e., natural mineral and organic substances, industrial and agricultural waste, as well as especially developed materials [5,6]

Methods

Results

Conclusion