Taxonomic survey of nickel hyperaccumulating plants in a mining site on Luzon Island, Philippines

Abstract

Plants that accumulate large amounts of heavy metals can be useful for environmental phytoremediation. These hyperaccumulators are capable of tolerating high concentrations of metals which are otherwise toxic to non-hyperaccumulators. This study aimed to account and categorize hyperaccumulating plant species in the Lagonoy ophiolite complex located in Camarines Sur province on Luzon Island. Plants were collected from several sampling sites within the mining area, identified, and their nickel content was measured using AAS. A total of 44 species from 30 families were collected and classified into non-accumulators, hemiaccumulators, hyperaccumulators and hypernickelophores based on the nickel level ranges defined in the work of Fernando et al. (2013). Six species were classified as non-nickel accumulators, in which the nickel content was < 100 ppm (1 ppm=1 μg Ni/g dry matter). Twenty-one species were classified as hemiaccumulators, having 100-999 μg/g Ni levels. There were 11 species of hyperaccumulators with nickel content of > 1000 μg/g Ni in dry matter and six hypernickelophores with nickel content of > 10000 μg/g Ni in dry matter. The plant with the highest nickel content was Lygodium circinnatum (Burm.f.) Swartz. The potential of this fern as a phytoremediation plant is discussed.