Distribution features and environmental risk assessment of heavy metals in apple tree plantations in Luochuan tableland

Based on systematic sampling and experimental analysis, the distribution features and environmental risk assessment of heavy metals in a typical profile, LC profile, of apple tree plantation in Luochuan tableland were investigated. The heavy metals investigated in the study included As, Cr, Cu, Ni, Pb, Zn, Mn, Co and V. Geoaccumulation index, element accumulation index and potential ecological risk index were used in the assessment. Based on the assessment, As, Cr, Ni, Mn and V have similar vertical distribution trends, generally increasing from top to bottom. However, Cu, Pb, Zn and Co almost exhibits the same distribution trend in the soil profile, generally initially decreasing and then increasing from top to bottom. There is some degree of As, Cr, Cu, Ni, Mn, Co and V accumulation, the phenomenon not observed for Pb and Zn. Ecological risk index for As is the highest among the 9 heavy metals investigated. As has potential ecological risk index of 39.9, though far less than slight ecological risk threshold.