Figure 1

The Tukey boxplots of oxides and potential toxic elements of the surface and deep soils. QS and QD, the surface and deep soils developed in quaternary sediments; GS and GD, the surface and deep soils developed in granite plutons.
The Tukey boxplots of oxides and potential toxic elements of the surface and deep soils. QS and QD, the surface and deep soils developed in quaternary sediments; GS and GD, the surface and deep soils developed in granite plutons.