The identification of indigenous Cu and As metallophytes in the Lepanto Cu-Au Mine, Luzon, Philippines.

Abstract

The mining activities in the Lepanto Cu-Au Mine which is situated within the Mankayan Mineral District in the Philippines have exposed the arsenic (As)-rich copper (Cu)-gold (Au) and polymetallic ores to surface conditions. Cu and As dispersal into nearby soils and waters could pose health hazards to the natural ecosystems and human settlements. The study focused on the identification of indigenous metallophytes thriving in the area as well as the bioavailability of Cu and As in soils and its implication to the growth of the indigenous plants. Particular interests were on plant species that are capable of Cu and As absorption and have potential applications to mine rehabilitation. The samples were analyzed for total Cu and As contents. The soil samples were also subjected to different physicochemical analyses such as pH, organic matter, and nutrient content. Fern species had relatively high Cu and As contents in their biomass than other plant species found in the study area. The Cu and As concentrations in the plants might have been strongly influenced by the bioavailability of the metal and metalloid which were dependent on the physicochemical properties of the soil such as pH, organic matter, and nutrient contents. These identified metallophytes namely Dicranopteris linearis, Histiopteris incisa, Pityrogramma calomelanos, Pteris vittata, Nephrolepis hirsutula, Pteris sp., Pinus sp., Thysanolaena latifolia, and Melastoma malabathricum have tolerated the different Cu and As concentrations in the soil thus could be useful and effective for ecological restoration as an option to post-mining rehabilitation.