where Mshoot is the pollutant concentration in shoots of the plants
(mg kg−1); Wshoot is the plant dry aboveground biomass (g); Msoil
is the pollutant content in soil (mg kg−1) and Wsoil is the amount
of soil in the pot (g). The RF values can reflect the amount of a
pollutant extracted by a plant from the soil, thus indicating the
phytoextraction efficiency