Average measured concentrations of rare earth elements (mg REE/kg dry soil) in control and dosed soils as compared to the expected nominal doses.

Values for control soils represent the detected background REE levels in the artificial soil. Percent recovery for dosed soils, calculated as: (average [REE] measured at a given dose—average measured [REE] in control soils) / (nominal dose), are presented in parentheses.a Nominal doses for Pr were 0.00, 30.21, 57.40, 109.50, 207.68, 393.47, 747.66, and 1423.59; % recovery for Pr was based on these values.Average measured concentrations of rare earth elements (mg REE/kg dry soil) in control and dosed soils as compared to the expected nominal doses.