Reforestation Impacted Soil Heavy Metal Fractionation and Related Risk Assessment in the Karst Area, Southwest China

Human agricultural activities have resulted in widespread land degradation and soil contamination the karst areas. However, effects of reforestation after abandonment on mobility risks heavy metals been rarely reported. In present study, six profiles were selected from cropland abandoned with Puding regions Southwest China. The Community Bureau Reference (BCR) sequential extraction method was used to evaluate compositions different chemical fractions metals, including Fe, Mn, Cr, Zn, Ni, Cd. total contents Cd, Mn croplands significantly higher than those croplands. For all soils, Fe mainly concentrated residual (>85%), whereas Cd mostly observed non-residual (>65%). Zn These results indicated that content decreased reforestation. individual factor (ICF) risk assessment code (RAC) showed contributed considerable soils. global (GCF) potential ecological index (RI) suggested low investigated croplands, moreover they can be further reduced