Jatropha curcas and assisted phytoremediation of a mine tailing with biochar and a mycorrhizal fungus

ABSTRACT

Soil pollution is an important ecological problem worldwide. Phytoremediation is an environmental-friendly option for reducing metal pollution. A greenhouse experiment was conducted to determine the growth and physiological response, metal uptake, and the phytostabilization potential of a nontoxic Jatropha curcas L. genotype when grown in multimetal-polluted conditions. Plants were established on a mine residue (MR) amended or not amended with corn biochar (B) and inoculated or not inoculated with the mycorrhizal fungus Acaulospora sp. (arbuscular mycorrhizal fungus, AMF). J. curcas was highly capable of growing in an MR and showed no phytotoxic symptoms. After J. curcas growth (105 days), B produced high desorption of Cd and Pb from the MR; however, no increases in metal shoot concentrations were observed. Therefore, Jatropha may be useful for phytostabilization of metals in mine tailings. The use of B is recommended because improved MR chemical properties conduced to plant growth (cation-exchange capacity, organic matter content, essential nutrients, electrical conductivity, water-holding capacity) and plant growth development (higher biomass, nutritional and physiological performance). Inoculation with an AMF did not improve any plant growth or physiological plant characteristic. Only higher Zn shoot concentration was observed, but it was not phytotoxic. Future studies of B use and its long-term effect on MR remediation should be conducted under field conditions.

KEYWORDS:

• Acaulospora sp
• heavy metals
• physic nut
• phytostabilization
• translocation factor

Acknowledgments

The authors thank Dr. Ariadna Sánchez López for fungal isolation of Acaulospora sp. from metal-polluted mine tailings, from metal-polluted mine tailings and her help on statistical analysis, Dr. Claudia Hidalgo for kindly providing the B to continue this research, the Microscopy Unit at the Colegio de Potgraduados for allowing the use of equipment facilities, CEPROBI for use of its greenhouse spaces, and Jaime Cruz Díaz for his technical support of soil physical–chemical analysis. The authors also thank anonymous reviewers whose valuable suggestions improved the content of this manuscript.

Funding

The third author is grateful for the scholarship granted by the Consejo Nacional de Ciencia y Tecnología (CONACyT) for her master's studies. This research was partially supported by project research: Arbuscular mycorrhizal symbiosis in the production of Jatropha curcas L. for bioenergy (Fideicomiso No. 167304, Colegio de Postgraduados).