Profile Distribution and Source Identification of Potentially Toxic Elements in North Nile Delta, Egypt

摘要

Vertical distribution and source appointment of potentially toxic elements (PTEs) provide a deeper vision for soil contamination. Contamination factor (CF), contamination degree (CD), enrichment factor (EF), principal component analysis (PCA), and cluster analysis (CA) were used for soil contamination assessment in north Nile Delta, Egypt. Twenty-one soil profiles representing main geomorphic units were dug, and 63 soil samples were collected at three depth intervals (0-30, 30-60 and 60-90 cm). Mean values of the three layers showed that Al, Fe, Mn, Cr, Cu, Pb, Mo, and V did not exceed average natural content of the Earth's crust, while As, Cd, Co, Ni, and Zn exceeded that limit, except in the sand sheets unit. The studied elements showed irregular vertical distribution trend, except Cr, Ni, and Mo. Both Cr and Ni showed a downward migration, while Mo accumulated in the topsoil. Based on mean values, the CF indicated low contamination with Cr, Cu, Pb, Mn, Mo and V, moderate contamination with Cd and Zn, considerable contamination with As, Co, and Ni, while the CD was low to considerable. Furthermore, the EF indicated safe degree for Cr, Cu, Pb, Mo and V, deficiency to a minimal degree for Cd and Zn, while moderate degree for As, Co, and Ni. The PCA and CA indicated that soil parent materials controlled Al, Fe, Mn, Cu, Cr, Co, Pb, Ni, Mo, and V, while agricultural activities controlled As, Cd and Zn. Similar investigations should be considered in various regions in Egypt to verify potential sources of PTEs and to manage pollution of agricultural fields.