*2.6. Data Analysis*

SPSS 22.0 and Minitab version 17.0 statistics software were used for data analysis. At 95% confidence interval (*p* < 0.05); analysis of variance (ANOVA) was used to test for significance in mean concentrations of metals across sites both in sediment and the freshwater mollusc *Bellayma unicolor*. Pearson correlation, principal component analysis (PCA) and cluster analysis were used to determine the sources of metal pollutants, the significant relationship between the metals, the relationship between the sites in terms of heavy metal concentration, and the influence of metal concentrations on antioxidant enzymes activities in *Bellamya unicolor*.
