TEMPORAL AND SPATIAL HYDROGEOCHEMICAL DYNAMICS OF THE TROPICAL WOURI ESTUARY: A COMPARATIVE STUDY OF 2019 AND 2023

This study presents a comparative hydrogeochemical analysis of the tropical Wouri Estuary, conducted in 2019 and 2023. The Wouri Estuary is surrounded mangrove forests that are major carbon sink in the environment. It is drained by three major rivers and several tidal creeks thereby supporting a rich and diverse ecosystem. The estuary is severely stressed by anthropogenic activities due to urbanization and industrial activities. This research aims to evaluate the temporal changes in the water quality parameters and identify the potential anthropogenic and natural influences affecting the estuary's hydrogeochemistry.

The surveys encompassed comprehensive sampling and analysis of water from multiple points from the Wouri river into the estuary along a transect running NE – SW. Key parameters measured included pH, electrical conductivity, salinity, dissolved oxygen, major ions (Ca²⁺, Mg²⁺, Na⁺, K⁺, Cl⁻, SO₄²⁻, HCO₃⁻), and stable isotopes of oxygen and carbon.

The results indicated significant spatial heterogeneity and temporal dynamics in the hydrogeochemical composition of the estuary. Notable changes in the hydrogeochemical profile of the estuary over the four-year period. Advanced statistical techniques, including principal component analysis (PCA) and hierarchical cluster analysis (HCA), were employed to identify the key factors driving the observed patterns, potential pollution sources and underlying geochemical processes.

The findings underscore the urgent need for enhanced environmental monitoring and management strategies to mitigate the impact of human activities on the Wouri Estuary's water quality. This study provides a comprehensive baseline for future hydrogeochemical investigations and demonstrates the need for long-term monitoring in estuarine ecosystems for the formulation of effective management strategies.