Fig 1.
Map of study site showing the sampling stations in Ankobra estuary.
Map created in QGIS using data from OpenStreetMap contributors, public domain spatial datasets, and shapefiles developed in ArcGIS Pro.
Table 1.
Summary of physicochemical parameters (Mean, Min, Max, StDev, and P-value) across sampling stations in the Ankobra estuary.
Table 2.
Tukey’s Post Hoc test results of the physico-chemical parameters (Mean ± Standard Error).
Fig 2.
Mean concentration (±S.E.) of mercury and lead in water samples from the Ankobra estuary.
The bar plot shows the mean concentrations of mercury (a) and lead (b) (mg/L) in water samples across different months for three sampling stations in the Ankobra estuary. Bars represent average concentrations with standard deviation error bars. Tukey’s post hoc test indicates significant differences among stations, with letters ‘a’, ‘b’, and ‘c’ for mercury and ‘a’ and ‘b’ for lead.
Table 3.
Comparison of mean sediment mercury and lead concentrations with average shale values and sediment quality guidelines (ERL/ERM) for ecological risk assessment.
Fig 3.
Mean concentration (±S.E.) of mercury and lead in sediment samples from the Ankobra estuary.
The bar plot displays the mean concentrations of mercury (a) and lead (b) (mg/Kg) in sediment samples across different months for three sampling stations in the Ankobra estuary. Bars represent average concentrations with standard deviation error bars. Tukey’s post hoc test indicates significant differences among stations, with letters ‘a’, ‘b’, and ‘c’ for mercury and no difference observed in lead across stations.
Fig 4.
Mean concentration (±S.E.) of mercury and lead in C. nigrodigitatus from Ankobra estuary.
The box plot shows the mean concentrations of mercury (a) and lead (b) (mg/Kg) in fish samples from the Ankobra estuary across the sampling months. Bars represent average concentrations with standard deviation error bars.
Table 4.
Monthly variation in total length and body weight of Chrysichthys nigrodigitatus sampled from the Ankobra estuary.
Fig 5.
Pearson correlation matrix showing relationships between physicochemical parameters and toxic metal concentrations in the Ankobra estuary.
Circle size and color indicate the strength and direction of correlations (blue: positive, red: negative), with larger circles representing stronger associations.
Fig 6.
Principal Component Analysis (PCA) biplot showing the relationships among physicochemical parameters of water and toxic metals in water, sediment, and fish tissues.
Variables are projected along Principal Component 1 (PC1: 28.2% variance) and Principal Component 2 (PC2: 25.0% variance), illustrating their correlations and contributions to observed environmental gradients.
Table 5.
Bioaccumulation Factor (BAF) of mercury and lead in gills and liver of C. nigrodigitatus from Ankobra estuary.