Bioaccumulation and Health Risk Assessment of Heavy Metals in Oysters (Crassostrea gasar) from Iko River Marine Ecosystem, Nigeria
Keywords:
Heavy metals, oysters (Crassostrea gasar), bioaccumulation, ecosystem, biota, organic pollutantsAbstract
Heavy metal contamination is a major global problem threatening the sustainability of marine (aquatic) environments, biota species and humans who ingest resources from the contaminated ecosystems. This study aimed to investigate the seasonal variation, bioaccumulation, and associated human health risks of selected heavy metals in oysters (Crassostrea gasar) from Iko River marine ecosystem, Nigeria. The heavy metals considered are; zinc, lead, cadmium, copper, nickel, vanadium, cobalt and chromium. The heavy metals were determined using inductively coupled plasma – optical emission spectrometer (ICP-OES). The results indicated bioaccumulation of the metals determined in Crassostrea gasar in the order of magnitude (from the five sampling sites) Zn > Fe > V > Cu > Mn > Ni > Pb > Cr, whilst, Co, Ag and Cd were below detection limit. By the bioaccumulation factor (BCF) quality guidelines ranking scheme the present study has indicated that Zn, Mn, Cd, Pb, Ni, have low concerns (BCF < 250) at the five sampling sites. This study demonstrates that Crassostrea gasar in Iko River significantly bioaccumulate heavy metals, with zinc showing the highest levels across seasons. Although Cd and Co were not detected, several metals exceeded recommended dietary limits, posing health risks to consumers. The findings highlight oysters as effective bioindicators and underscore the urgent need for regular monitoring and remediation strategies in Eastern Obolo coastal ecosystems.
References
Akpan, S. B., Abraham, N. A., Nkannang A., & Essien J. P. (2019). Fate of 2-and 3-ring polycyclic aromatic hydrocarbons in estuarine mudflat from Iko River estuary, Nigeria. Journal of Applied Science and Technology, 11(2):148-156.
Aljahdali, M. O., & Alhassan, A. B. (2020). Ecological risk assessment of heavy metal contamination in mangrove habitats using biochemical markers and pollution indices: A case study of Avicennia marina L, in Rabigh Lagoon, Red Sea. Saudi Journal of Biological Sciences, 27: 1174-1184.
Ansari, T. M., Marr, I. L., & Tariq, N. (2004) Heavy metals in marine pollution: A mini review. Journal of Applied Sciences, 4 (1): 1-20.
APHA, AWCF, APHA. (2005). Standard methods for the examination of water and wastewater. American Water Works Association. 21st Edition. New York.
Benson, U. N., & Etesin, U. M. (2007). Metal contamination of surface water, sediments and Tympanotonus fuscatus Var. Radula of Iko and environmental impact due to Utapete gas flare station, Nigeria. The Environmentalist 28 (3): 195 – 202. ISBN 1573-2991.
Botta, R; Asche, F.; Borsum, J. S. & Camp, E. V. (2020). A review of Global Oyster Aquaculture production and consumption. Marine Policy 117:103952
Claudia T., Jules, M. Blais, E. Y. & Hing Man C. (2021). Health risk assessment of inorganic arsenic exposure through fish consumption in Yellowknife, Northwest Territories, Canada, Human and Ecological Risk Assessment: An International Journal, 27:4, 1072-1093, DOI: 10.1080/10807039.2020.1799187
EIA (2020). Environmental impact assessment of the proposed Utapete Field Development Project (Draft Report) submitted to Federal Ministry of Environment, Abuja, Nigeria, June, 2020.
Enemugwem, J. H. (2009). Oil pollution and Eastern Obolo human ecology, 1957-2007: African Research Review: International Multidisciplinary Journal 3 (1): 136-151.
Etesin, U., Udoinyang, E., & Harry, T. A. (2013). Seasonal variation of physio-chemical parameters of water and sediments from Iko river, Nigeria. Journal of Environment and Earth Science, 3 (8): 95-100.
Etesin, U. M., Thomas, A. H, Isotuk, U. G. (2021). Assessment of the Quality of water samples from Private Boreholes in Eket Local Government Area, Akwa Ibom State, Nigeria. Researchers Journal of Science and Technology. 1: 72 – 88.
Etesin, U. M., Isotuk, U. G. & Essien, A. L (2025). Distribution of Heavy metals in sediments and surface waters from Iko River Marine Ecosystems, Akwa Ibom State, Niger Delta, Nigeria. Communication in Physical Sciences., 12(2) 434-454. University of Nigeria, Nsukka, Nigeria.
Fang, Z., Cheung, R.Y. H., & Wong, M. H. (2003). Heavy metals in oysters, mussels and clams collected from coastal sites along the Pearl River Delta, South China. J. Environ. Sci (China). 15 (1): 9-24.
International Agency for Research on Cancer (IARC) (2010). Working Group on the Evaluation of Carcinogenic Risks to Humans. Some non-heterocyclic polycyclic aromatic hydrocarbons and some related exposures. IARC Monographs on the evaluation of carcinogenic risks to humans; 92:1.
Liu, D., Wang, J., Yu, H., Gao, H., & Xu, W. (2021). Evaluating ecological risks and tracking potential factors influencing heavy metals in sediments in an urban river. Environ. Science Europe 33 (42).
Maher, W. A., Taylor, A. M., Batley, G. E. & Simpson, S. L. (2016). Bio-accumulation. In: Simpson, S. L., and Batley, G. E. (Eds). Sediment quality assessment: a practical guide, 2nd ed. CSIRO Publishing, Australia: 123-156.
Manickavasagam, S., Sudhan, S., Bharathi., & Aanand, S. (2019). Bioindicators in aquatic environment and their significance. J. Aqua Trop, 34 (1): 73-79.
Mok, J. S., Yoo, H. D., Kim, P. H. K., Yoon, H. D., Park, Y. C., Lee, T. S., Kwon, J. Y., Son, K. T., Lee, H. J., Ha, K. S., Shim, K. B., & Kim, J, H. (2015). Bioaccumulation of heavy metals in oysters from the Southern Coast of Korea: assessment of potential risk to human health. Bull. Environ. Contam. Toxicol. 95: 749 – 755.
Morais, S., Costa, F. G., & Pereira, M. L. (2012). Heavy metals and Human Health. In: Oosthuizen, J. (Ed). Environmental health - Emerging issues and Practice. IntechOpen. doi:10.5772/29869.
Naggar, Y. A., Khalil, M. S., & Gharab, M. A. (2018). Environmental Pollution by heavy metals in the aquatic ecosystem of Egypt. Open Access journal of Toxicology (Review article), 3 (1). Doi: 10.1980/OAJT. 2018. 03.555603.
Naser, H. A. (2013). Assessment and management of heavy metals pollution in the marine environment of the Arabian Gulf: A review. Marine Pollution Bulletin, 72 (1): 6-13.
Nwaichi, E. O. & Ntorgbo, S. A. (2016). Toxicology Reports, 3, 167-172. URL: https://www.sciencedirect.com/science/article/pii/S2214750016300051.
Olujide, M. G. (2006). Perceived effects of Oil spillage on the livelihood activities of women in Eastern Obolo Local Government Area of Akwa Ibom State. Journal of Human Ecology 19 (4): 259 – 266.
Tchobonoglous, G., Burton, F. L., & Stensel, H. D. (2004). Wastewater engineering, treatment and reuse 4th ed. McGraw Hill, Boston.
Ubong, U. U., Ekwere, I. O., & Ikpe, E. E. (2020). Risk and toxicity assessment of heavy metals in Tympanotonous fuscatus and sediments from Iko river, Akwa Ibom State Nigeria. International Journal of Environment and climate change, 10 (3), 38-47.
Udoidiong, O. M. (2010). Threats to species of some mangrove wetland in Eastern Obolo, Nigeria. World Journal of Applied Science and Technology 2 (2): 232-244.
Ufikairom G. Isotuk, Usoro M. Etesin, Edet W. Nsi, & Emmanuel J. Ukpong (2023) Ecological and Health Risk Assessment of Heavy Metals in Sediments, Surface Waters and Oysters (Crassostrea Gasar) from Eastern Obolo Marine Ecosys-tems, Akwa Ibom State, Nigeria.
Communication in Physical Sciences 2020, 9(4): 545 -571, University of Nigeria, Nsukka, Nigeria.
US EPA (2007). Framework for metals assessment. EPA 120/R-07/001, March. United States Environmental Protection Agency, office of the Science Advisor Risk Assessment Forum. Washington DC. 20460.
US EPA (2023) EPA Expobox: Exposure assessment tools by media - aquatic biota. United States Environ Protection Agency.
Weissmannova, H. D., Mihocova, S., Chovanec, P., & Pavlovsky, J. (2019) Potential ecological risk and human health risk assessment of heavy metals pollution in industrial affected soils by coal mining and metallurgy in Ostrava, Czech Republic. Int. J. Environ. Res. Public Health 16 (22): 4495.
WHO (World Health Organisation) (2010) Human health risk assessment toolkits: Chemical Hazard: WHO/IPCS Harmonization project document, No 8.
Yawo, O. J., & Akpan, I. O. (2021) Assessment of heavy metals concentration in sediments of Utibete River, Eastern Obolo, South Eastern Nigeria using particle induced X-ray emission (PIXE) technique. Researchers Journal of Science and Technology (REJORT), 1: 17-36
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