Arsenic Uptake by Two Hyperaccumulator Ferns from Four Arsenic Contaminated Soils

Abstract

A greenhouse study was conducted to evaluate and compare arsenic accumulation from four arsenic contaminated soils by two arsenic hyperaccumulators, Pteris vittata and Pteris cretica. After growing in soils for six weeks, the plants were harvested and separated into above- and below-ground biomass. Total As, P, Ca, K, glutathione and biomass were measured for the plants, and total As, Mehlich-3 P and As, exchangeable K and Ca, and arsenic fractionation were performed for the soils. Pteris vittata had significantly higher total biomass (14 g/plant) and As accumulation than P. cretica. Arsenic accumulation in both ferns followed the arsenic concentrations in the soil. The P/As molar ratio in the fronds, growing in arsenic contaminated soils, ranged from 80 to 939 in P. vittata and 130 to 421 in P. cretica. Plant arsenic concentrations were significantly positively correlated with Mehlich-3 arsenic in the soils. Soil pH was also significantly correlated with Mehlich-3 arsenic before and after plant uptake. Plant As uptake was significantly correlated with exchangeable potassium in the soil before plant uptake. Glutathione availability was not implicated as a major detoxification mechanism in these ferns. Though both plants were effective in taking up arsenic from various arsenic contaminated soils, P. vittata was overall a better candidate for phytoremediation of arsenic contaminated soils.