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ORIGINAL PAPER

Source apportionment and associated potential ecological risk assessment of heavy metals in coastal marine sediments samples in Ondo, Southwest, Nigeria Lasun T. Ogundele1

•

Patrick O. Ayeku2

Ó Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract Heavy metals are released into the sediments in aquatic environment from both natural and anthropogenic sources and they are considered as worldwide issue due to their deleterious ecological risks and food chain disruption. In this study, sediments samples were collected at three major sites (Awoye, Abereke and Ayetoro) along Ondo coastal marine area using VanVeen grab sampler. The concentrations of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn were determined by employing Atomic Absorption Spectroscopy (AAS). The combined concentrations data were subjected to Positive Matrix Factorization (PMF) receptor approach for source identification and apportionment. The probable risks that might be posed by heavy metals in the sediment were estimated by potential and integrated ecological risks indices. Among the measured heavy metals, Fe had the average concentrations of 20.38 ± 2.86, 23.56 ± 4.16 and 25.32 ± 4.83 lg/g at Abereke, Awoye and Ayetoro sites, respectively. The PMF resulted in identification of four sources of heavy metals in the sediments. The resolved sources and their percentage contributions were oil exploration (39%), industrial waste/sludge (35%), detrital process (18%) and Mn-sources (8%). Oil exploration activities and industrial wastes are the major sources that contribute heavy metals into the coastal sediments. The major pollutants that posed ecological risks to the local aquatic ecosystem are As, Pb, Cr and Cd (40 B Eri \ 80) classifying the sites as moderate risk. The integrate risks values of Awoye, Abereke and Ayetoro are 231.2, 234.0 and 236.4, respectively suggesting that the study areas had a moderate ecological risk. The study showed the suitability of PMF receptor model for source identification of heavy metals in the sediments. Also, the intensive antropogenic activities and natural sources could largely discharged heavy metals into the study area, which may increase the heavy metal contents of the sediments and further contribute to the associated ecological risk, thus affecting the local aquatic ecosystem. Keywords Positive matrix factorization  Sediments  Heavy metals  Sources  Ecological risks

1 Introduction Coastal marine environment is a complex system and it is greatly affected by both anthropogenic and natural processes leading to metal pollution of sediment in the coastal area (Qian et al. 2015). Studies of contamination of

& Lasun T. Ogundele [email protected] 1

Department of Physics, University of Medical Sciences, Ondo, Nigeria

2

Department of Biological Sciences, Federal University, Gasua, Nigeria

sediments had attracted the attention of the researchers worldwide because it provides food for the aquatic organism, acts as a vast sink for aquatic pollutants and geochemical trap for several po