Ecological Assessment of Heavy Metal Contamination of Tympanotonus fuscatus in Iko River Basin

Abstract

Background: Ecological assessment of heavy metal contamination of Tympanotonus fuscatus in Iko River Basin was investigated for a period of twelve (12) months between September 2022 – August, 2023 with aim of understanding the ecological status and the safety of consuming the mangrove periwinkle (Tympanotonus fuscatus) obtained from the Estuary. Methodology: Samples of T. fuscatus were bought from landings of artisanal isheries in Iko River Basin on a monthly basis for a period of 12 months. The samples were placed immediately in poly-ethylene bags, put into an isolated container of polystyrene icebox, and then brought to the laboratory prior to laboratory analysis. In the laboratory standard analytical procedures were adhered to in the preparation of samples prior to heavy metal determination using Perkin-Elmer Analysts 800 Atomic Absorption Spectrophotometer (AAS). Results: From the results it was found out that the mean concentration of heavy metal throughout the study duration followed the trend Fe > Zn > Cr > Mg > Cu > Pb > Ni > Cd for the dry season while a different trend Fe > Zn Pb >> Mg > Ni >> Cu > Cr > Cd was observed during the wet season. Amongst the metals studied, seasonal variation was observed for zinc. The dominance of Fe and Zn throughout the study duration was attributed to their abundance in the earth’s crust. Correlation analysis showed a strong positive relationship between metal pairs in the dry season which portends that an increase in the concentration of one metal mandates a corresponding increase in the other while a negative correlation was observed between metals pairs in the wet season which signiies an inverse relationship. The hierarchical cluster dendrogram delineated the metals into four (4) cluster groups in the dry season and three (3) cluster groups in the wet season based on concentration gradient and source of contamination. Conclusion: However, the results of the indings showed that the concentration of heavy metal in the tissue of the studied species fell within the WHO/FAO recommended threshold limit for safe consumption of aquatic seafood. By mitigating the sources of contamination and implementing effective conservation strategies, we can safeguard T. fuscatus and preserve the ecological balance of the vital estuarine environments they inhabit through collaborative efforts from regulatory bodies, industries, and local communities.