Copper uptake by Pteris melanocaulon Fée from a Copper-Gold mine in Surigao del Norte, Philippines

ABSTRACT

The ability of some plants to take up metal contaminants in the soil has been of increasing interest as an environmental approach to pollution clean-up. This study aimed to assess the ability of Pteris melanocaulon for copper(Cu) uptake by determining the Cu levels in the fern vis-à-vis surrounding soil and the location of Cu accumulation within its biomass. It also aimed to add information to existing literature as P. melanocaulon are found to be less documented compared to other fern metal accumulators, such as P. vittata. The P. melanocaulon found in the Suyoc Pit of a Copper-Gold mine in Placer, Surigao del Norte, Philippines exhibited a high Bioaccumulation Factor(BF) of 4.04 and a low Translocation Factor(TF) of 0.01, suggesting more Cu accumulation in the roots (4590.22 ± 385.66µg g⁻¹ Cu). Noteworthy was the Cu concentration in the rhizome which was also high (3539.44 ± 1696.35µg g⁻¹ Cu). SEM/EDX analyses of the Cu content in the roots indicated high elemental %Cu in the xylem (6.95%) than in the cortex (2.68%). The high Cu content in the roots and rhizomes and the localization of Cu in the xylem manifested a potential utilization of the fern as a metallophyte for rhizofiltration and phytostabilization.

KEYWORDS:

• Metal accumulation
• metallophytes
• phytoremediation
• phytostabilization
• black-stemmed fern

Acknowledgments

The authors would like to thank the Department of Science and Technology Philippine Council for Industry, Energy and Emerging Technology Research and Development (DOST-PCIEERD) for funding this research. We would also like to extend our gratitude to the following: a) the Ateneo de Manila University for providing the facilities, b) Dr. Dennis Apuan and Ms. Mary Jean Apuan of Xavier University for their assistance during fieldwork and research experimentations, c) Dr. Julie Barcelona and Dr. Pieter Pelser of SIU, curators of the PhytoImages website, for plant species verification, and to d) Manila Mining Corporation for providing access to their mine site in Surigao del Norte. The comments and suggestions provided by the two reviewers are acknowledged of which have greatly improved the presentation of data and discussions.