Assessment of seawater flux and its impact on ayetoro coastal community of ondo state, Nigeria

Climate change impact had given rise to incessant flooding exacerbated by high tidal fluctuations, sea level rise and its accompanying negative impacts such as land degradation and seawater incursion into freshwater sources. Hence, the need to assess the hydrochemistry and anthropogenic pollutants in water, sediment and representative fish samples of Aiyetoro coastal waters. Thirteen sampling stations (including 2 groundwater stations and 3 control stations) were selected to determine the concentration and spatial distributions of hydro-chemical characteristics and heavy metals concentrations. The results of the ionic concentrations (e.g., Calcium Ca2+,Magnesium Mg2+,Sodium, Na+, Potassium K+, Nitrate NO3-, Phosphate PO43-, Sulphate SO42- and Chloride Cl-) further showed higher values that exceed the World Health Organization (WHO) standard, Federal Environmental Protection Agency (FEPA), and Federal Ministry of Environment (FEMENV) permissible limit for portable water and coastal water for marine life sustainability. The result further affirms the high impact of land degradation and saline water intrusion. Low pH, Dissolved Oxygen (DO) at some stations indicate increased anthropogenic activities. Heavy metal analysis further showed high Lead (Pb) concentrations in water, Copper (Cu), Manganese (Mn), Chromium (Cr) in sediment and Cu, zinc (Zn), Pb, cadmium (Cd), cobalt (Co) and Nickel (Ni) in representative fish samples. This study establishes that sea-level rise, land degradation, flooding and human-induced anthropogenic activities have negatively impacted Aiyetoro community, hence an urgent need for bioremediation.