IJMSMT · Original Research Article Vol. 1, No. 1 (October 2026), pp. 110–119
Marine Environment and Sustainable Transportation

SPATIAL, MONTHLY AND SEASONAL VARIABILITY OF HEAVY METALS IN SEDIMENTS FROM AWOYE RIVER, ONDO STATE, NIGERIA

Emmanuel Rufus ARIBO* — University of Benin, Nigeria
* Corresponding author: ariboharibo90@gmail.com
Published: 1 November 2026 •Received: 20 Aug 2026 •Accepted: 21 Sep 2026 •DOI: 10.5281/zenodo.23852249 • Licence: CC BY 4.0

Abstract

Heavy metals in aquatic sediments may persist and accumulate over time, making sediments useful for assessing spatial and temporal patterns of metal distribution. This study evaluated the spatial, monthly and seasonal variability of iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), nickel (Ni), cadmium (Cd), vanadium (V), chromium (Cr) and lead (Pb) in sediments from Awoye River, Ondo State, Nigeria. Sediment samples were collected from three stations between January and June 2015 and analysed using atomic absorption spectrophotometry. Metal concentrations were evaluated across stations and months using analysis of variance, while dry- and rainy-season concentrations were compared using the statistical procedures applied in the original study. Station 1 recorded the highest numerical mean concentrations of all nine metals. Significant spatial differences were observed for Zn, Mn, Cu, Cd, V, Cr and Pb, with Station 1 differing significantly from Stations 2 and 3, whereas Fe and Ni showed no significant differences among stations. Monthly variation was significant for Fe and Ni only: Fe concentrations were significantly lower in January and February than from March to June, while Ni was significantly higher in January than from February to June. Seasonal patterns were heterogeneous across metals and stations rather than showing uniform rainy-season enrichment. Rainy-season concentrations were numerically higher for most metals at Stations 1 and 3, whereas Station 2 displayed mixed patterns. The study concludes that sediment-metal distribution in Awoye River during the 2015 sampling period was characterised by pronounced spatial heterogeneity and metal-specific temporal variation rather than a uniform monthly or seasonal response.

Keywords: Awoye River; heavy metals; sediment; spatial variability; monthly variation; seasonal variation
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References

  1. Adebule, M. E., & Oguntimehin, I. I. (2025). Geochemical assessment and statistical characterisation of heavy metal contamination in estuarine sediments of Ondo State, Nigeria. International Journal of Research and Innovation in Applied Science, 10(13), 91–99. https://doi.org/10.51584/IJRIAS.2025.101300007. RSIS International
  2. Akpan, N. A., Udombeh, R. B., & Ukpong, M. B. (2025). Assessment of seasonal variations of some heavy metals between water and sediment in Qua Iboe River, Oruk Anam, Nigeria. Journal of Materials Science Research and Reviews, 8(1), 124–134. https://doi.org/10.9734/jmsrr/2025/v8i1384. DOI
  3. Anderson, J. (1974). A study of the digestion of sediment by the HNO₃-H₂SO₄ and the HNO₃-HCl procedures. Atomic Absorption Newsletter, 13(1), 31–32.
  4. Anyanwu, I. N., Beggel, S., Sikoki, F. D., Okuku, E. O., Unyimadu, J.-P., & Geist, J. (2023). Pollution of the Niger Delta with total petroleum hydrocarbons, heavy metals and nutrients in relation to seasonal dynamics. Scientific Reports, 13, 14079. https://doi.org/10.1038/s41598-023-40995-9. Nature
  5. Aribo, E. R. (2026). Station-based, monthly and seasonal variations in heavy metal concentrations in water from Awoye River, Ondo State, Nigeria. FUDMA Journal of Sciences, 10(20), 195–201. https://doi.org/10.33003/fjs-2026-1020-6048. fjs.fudutsinma.edu.ng
  6. Asuquo, A. P., Akpan, I. I., Abiaobo, N. O., & George, U. U. (2023). Heavy metal assessment in sediments of Qua Iboe River Estuary, South-South, Nigeria. Asian Journal of Research in Zoology, 6(4), 27–34. https://doi.org/10.9734/ajriz/2023/v6i4119. DOI
  7. Baker, D. E., & Amacher, M. C. (1982). Nickel, copper, zinc, and cadmium. In A. L. Page, R. H. Miller, & D. R. Keeney (Eds.), Methods of soil analysis: Part 2. Chemical and microbiological properties (2nd ed., Agronomy Monograph No. 9, pp. 323–336). American Society of Agronomy and Soil Science Society of America. https://doi.org/10.2134/agronmonogr9.2.2ed.c19
  8. Garkuwa, N. A., Abubakar, K. A., Saidu, H., Abubakar, B., Gamawa, Z. R., & Suleiman, N. (2026). Heavy metal contamination in water and sediments of the Gongola River Complex, Nigeria: A seasonal and spatial assessment. Malaysian Journal of Science and Advanced Technology, 6(2). https://doi.org/10.56532/mjsat.v6i2.655. mjsat.com.my
  9. Idowu, G. A. (2022). Heavy metals research in Nigeria: A review of studies and prioritization of research needs. Environmental Science and Pollution Research, 29(44), 65940–65961. https://doi.org/10.1007/s11356-022-22174-x. fjs.fudutsinma.edu.ng
  10. Ikpo, M. S., Kanu, K. C., & Ogbonna, P. C. (2024). Seasonal dynamics of heavy metal pollution in water, sediment and fish of Oyivo River in Abia State, Nigeria. Production Agriculture and Technology, 20(2), 107–119. patnsukjournal.org
  11. Jolaosho, T. L., Elegbede, I. O., Ndimele, P. E., Marouani, M., Yusuf, A. O., Omoregha, J. K., Mustapha, A. A., Hungbo, J. J., & Rasaq, M. F. (2025). Seasonal and spatial variations of physicochemical parameters and heavy metals in surface water of interconnected Nigeria lagoons experiencing distinct anthropogenic disturbances. Scientific Reports, 15, 38816. https://doi.org/10.1038/s41598-025-22727-3. Nature
  12. Nubi, O. A., Popoola, S. O., Dada, O. A., & Otolorin, O. O. (2022). Spatial distributions and risk assessment of heavy metals and PAH in the southwestern Nigeria coastal water and estuaries, Gulf of Guinea. Journal of African Earth Sciences, 188, 104472. https://doi.org/10.1016/j.jafrearsci.2022.104472. fjs.fudutsinma.edu.ng
  13. Ogunsuyi, M. T., Dada, O. A., Ogundare, M. O., & Asiwaju-Bello, Y. A. (2026). Physicochemical characteristics of Nigerian estuaries and their patterns, drivers, and implications for environmental management. Discover Oceans, 3, 66. https://doi.org/10.1007/s44289-026-00182-w. Springer
  14. Ololade, I. A., Apata, A., Oladoja, N. A., Alabi, B. A., & Ololade, O. O. (2024). Appraisal of river sediments in southwestern Nigeria with a special focus on trace metals: Occurrence, seasonal variation, sources, and health risks. Ecological Frontiers, 44(1), 155–166. https://doi.org/10.1016/j.chnaes.2023.08.004. ScienceDirect
  15. Olowojuni, O., Olaifa, F. E., Oyebola, O. O., Ayotunde, D. T., Kelani, A. Z., & Olusola, S. E. (2025). Seasonal and spatial variations in water quality, heavy metal concentration in water, sediment and bioaccumulation in Pseudotolithus species from the Gulf of Guinea, Ondo State, Nigeria. Environmental Sciences Europe, 37, 181. https://doi.org/10.1186/s12302-025-01221-7. DOI
  16. Ouma, K. O., Shane, A., & Syampungani, S. (2022). Aquatic ecological risk of heavy-metal pollution associated with degraded mining landscapes of the Southern Africa river basins: A review. Minerals, 12(2), 225. https://doi.org/10.3390/min12020225.
  17. Umudi, E. Q., Ekanem, E., Ekpenyong, I. O., Ibrahim, S. M., Chukwuemeka, O. G., Abdulmajid, S., Chikwe, I., Henry, C., Victory, C., & Kennedy, E. O. (2025). Seasonal assessment of heavy metals concentrations in sediment of the Sapele River, Nigeria. Journal of Science Innovation & Technology Research, 9(9), 124–? https://doi.org/10.70382/ajsitr.v9i9.038.
  18. United States Environmental Protection Agency (USEPA). (1994). Sediment sampling (Environmental Response Team Standard Operating Procedure No. 2016, Rev. 0.0, November 17, 1994). U.S. Environmental Protection Agency.