Bioremediation with Ferns And The Physiology of Bioremdiation in Pteris vittata

Bioremediation can be defined as any process that uses microorganisms, fungi, green plants or their enzymes to return the natural environment altered by contaminants to its original condition.

Phytoremediation: The word's etymology comes from the Greek <phyto> = plant, and Latin <remedium> = restoring balance. Phytoremediation consists in mitigating pollutant concentrations in contaminated soils, water or air with plants able to contain, degrade or eliminate metals, pesticides, solvents, explosives, crude oil and its derivatives, and various other contaminants, from the media that contain them.

Accumulator plants have the facility to concentrate metals from soils that contain low as well as high concentrations of metals. Plants that show exceptional uptake of metals are known as hyperaccumulators.

Pteris vittata: a highly efficient accumulator of arsenic

Pteris vittata

Schematic diagram of arsenic uptake, translocation, detoxification, and sequestration in P.vittata

arbuscular mycorrhizae Agely et al. (2005) found that AM fungi tolerated arsenic amendments, increased frond dry mass at the highest arsenic application rate, and increased arsenic uptake across a range of phosphorous levels.

TABLE 2. Arsenic Hyperaccumulators in the World As hyperaccumulator location references Pteris vittata America Ma et al. (13) China Chen et al. (16) Cretan Brake China Wei et al. (95) Pityrogramma calomelanos Southern Thailand Francesconi et al. (96) Visoottiviseth et al. (17) Pteris cretica Pteris longifolia Pteris umbrosa Rothamsted Zhao et al. (43) Pteris multifida Poir China Du et al. (97) Pteris cretica chilsii Pteris cretica crista Pteris cretica rowerii Pteris cretica mayii Pteris cretica parkerii Aberdeen Meharg (10) Pteris biaurita Pteris quadriaurita Pteris ryukyuensis America Srivastava et al. (98) Pteris multifida Pteris oshimensis China Wang et al. (99) Pteris aspericaulis var. Nervosa Pteris fauriei f. Serrulata Pteris oshimensis China Wang et al. (100) Pteris umbrosa R. Br Australia Koller et al. (101)

Azolla caroliniana

Azolla caroliniana

Why phytoremediation? Why ferns? Phytoremediation is a cost effective, low technology treatment that uses plants to decrease the concentrations of toxic materials in soils and waters. The ferns that hyperaccumulate arsenic are candidates for phytoremediation as they are fast growing, can be harvested several times a year and are capable of removing substantial amounts of arsenic from the surrounding soil.

Questions and Concerns… the disposal of the contaminated vegetation has not yet been resolved soil or groundwater contamination with a single heavy metal is rare--multipollutant removal needs to be the goal of phytoremediation if plants are introduced to an area in order to carry out phytoremediation, the potential disruption of local ecosystems needs to be addressed

Sources Agely, A. A.; Sylvia, D. M.; Ma, L. Q. Mycorrhizae increase arsenic uptake by the hyperaccumulator Chinese brake fern (P. vittata L.). J. Environmental Quality 2005, 34, 2181–2186. Ma, L. Q.; Komar, K. M.; Tu, C.; Zhang, W.; Cai, Y.; Kennelley, E. D. A fern that hyperaccumulates arsenic: a hardy, versatile, fast-growing plant helps to remove arsenic from contaminated soils. Nature 2001, 409, 579. Qing-En Xie; Xiu-Lan Yan; Xiao-Yong Liao; Xia Li. The Arsenic Hyperaccumulator Fern Pteris vittata L. Environmental Science & Technology 2009, 43, 8488-8495 Stêpniewska, Z.; Bennicelli, R.P.; Balakhnina, T.I.; Szajnocha, K.; Banach, A.; Woliñska, A. Potential of Azolla caroliniana for the removal of Pb and Cd from wastewaters. International Agrophysics 2005, 19, 251-255. Su, Y. H.; McGrath, S. P.; Zhu, Y. G.; Zhao, F. J. Highly efficient xylem transport of arsenite in the arsenic hyperaccumulator Pteris vittata. New Phytologist 2008, 180, 434–441. Wilkins, Carolyn, and Salter, Leo. (2003). Arsenic hyperaccumulation in ferns: A review. Environmental Chemistry Group Bulletin of the Royal Society of Chemistry. July 2003 edition