Chemistry Research and Practice

Assessment of Contamination of Potentially Toxic Elements (PTEs) from Soil Matrices of Nigeria Maritime University premise

Abstract

Avwerosuo, E, Nworu, J. S, Arisabor, L, Akporere, G. U

This research study assessed the degree of contamination of potentially toxic elements (PTEs) from soil matrices of Nigeria Maritime University premise. Soil samples were further sieved using a nylon sieve (<125μm diameter). The samples were prepared in triplicates. Reagent blanks were included to check contamination. Twenty-five top soil samples were collected and analysed for PTEs using FAAS. The pollution level in soils were assessed using pollution load index (PLI) and potential ecological risk index (PERI). The mean values of the toxic elements in soil from the study area decreased in the order Cd < As < Fe < Pb < Co < Ni < Cu < Zn < Cr < Mn. The ranges were as follows: Cd (0.13-0.95 ppm); As (0.49-4.50 ppm); Fe (6.42-24.80 ppm); Pb (5.96-31.45 ppm); Co (2.93-51.80 ppm); Ni (4.27-82.48 ppm); Cu (7.42-84.90 ppm); Zn (9.10-184.36 ppm); Cr (29.80-234.00 ppm) and Mn (84.30-486.00 ppm). All the toxic elements were higher than crustal average values used as background values except Cr and Fe in some samples. Ni, As, Co and Cr were higher than FAO/WHO guidelines whereas only Cr was higher than EU standard in some soil samples. The PIs of Cu, Zn, Cd and Mn were within low to high contamination, Pb, Ni, Co, As and Cr were within low to middle contamination while Fe is categorized as low contamination. Pollution Load Index showed that the soil in the study area can be classified as unpolluted to moderately polluted and ranged from 0.28 to 2.76. The toxic elements showed Eir of <40 and indicated low ecological potential risk index except Cd, Co, Fe, As and Ni that showed low to moderate ecological potential risk. Cd contributed highest to the Ecological Risk (PERI) which ranged between 18.24 and 109.67 and indicated moderate risk.

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