Multivariate analysis of trace element pollution in the quaternary deposits of the eastern Dahomey Basin

Abstract

A range of geogenic and anthropogenic activities has led to contamination processes along coastline of Ondo State, this is particularly affecting the communities in this area. This situation has had a negative impact on the quality of soil and water. The aim of this research was to analyze soil quality by characterizing trace elements. For this study, 100 subsoil samples were collected at various depths, ranging from 80 to 120 cm. They were analyzed using high-resolution inductively coupled plasma mass spectroscopy to detect trace elements in the sediment. The results revealed Ba (533.78–23108.11, avg. 9036.15), Nb (0.19–4.09, avg. 0.82), Zr (1.90–22.76, avg. 4.95), Sr (0.62–24.85, avg. 9.24), Sc (0.16–6.30, avg. 1.26), V (2.80–106.25, avg. 22.25), Cr (98.57–2385.75, avg. 559.96). Others include; Co (0.13–4.06, avg. 0.89), Ni (2.58–22.60, avg. 7.89), Rb (0.08–4.13, avg. 1.66), Th (0.05–2.70, avg. 0.24), Hf (4.13–46.44, avg. 11.09), and U (4.03–39.66, avg. 9.17). Multivariate analysis was employed to help identify the sources of these elements. These showed variations from uncontaminated to contaminated conditions. Statistical analyses indicated that the contaminants originated from either natural or human-made sources. The multivariate analysis effectively distinguished between the geogenic and anthropogenic sources of the trace elements in the soil samples. Manganese (Mn) was primarily found to be from geogenic sources, as indicated by pedogenic factors. In contrast, cobalt (Co), nickel (Ni), and lead (Pb) were found to originate from emissions related to vehicles, phosphate fertilizers, and domestic activities. To mitigate ongoing contamination, it is recommended that routine environmental monitoring be conducted by those in authority to avoid repeated contamination in future.