Ex-situ phytoextraction using Pteris vittata as a sustainable way to protect soil resource

Abstract

Chemical industrial sites are potential land resources for urban construction, but the high concentration of heavy metals in soil restricts their timely redevelopment. Remediation treatment must be performed before the reutilization of these sites. Aiming to investigate the potential of Pteris vittata to remove arsenic (As) from an As-contaminated chemical industrial site, a 16-month ex-situ field experiment was conducted to monitor the dynamics of growth and As uptake of P. vittata. The shoot (pinnae and petiole) biomass increased linearly with the extension of time, and reached 1342gm-2 at the time of ~16 months after transplantation. The shoot As concentration in pinnae showed a “large increase followed by small decrease” tendency and reached its highest value of 2550mgkg-1 at the time of ~10 months after transplantation. Compared with the control that removed 5.1kg As ha -1, the addition of potassium dihydrogen phosphate at the dose of 600mg (P2O5) kg-1 or ammonium dihydrogen phosphate at the dose of 300mg (P2O5) kg-1 increased the As removal by P. vittata to ~13.0kgha-1. The total cost of ex-situ phytoremediation was 41.6 US$ t-1, being ~67% lower than that of common site remediation technologies such as soil washing. Ex-situ phytoremediation is suggested to enable a timely re-development of land resource and a sustainable protection of soil resource.