Testing the usability of sea mussel (Mytilus sp.) for the improvement of seawater quality—An experimental study

The aim of the present study has been to analyze the effect of Mytilus sp. on the quality of raw seawater (organic compounds and heavy metals concentrations). The experiment was conducted under laboratory conditions. Two groups of the sea mussel were used in the experiments: small (S group; mean shell length 28.54 ± 1.69 mm) and large ones (L group; mean shell length 35.07 ± 1.83 mm). The highest removal efficiency of organic compounds, Zn, Pb and Ni was observed for the water retention time in a reactor of 9 or 12 h. The differences between removal efficiencies of COD, Zn, Pb and Ni were significant and mainly dependent on the water retention time, less – on the mussels’ size (two-way ANOVA, p < 0.05). Unlike the other examined heavy metals, Cr revealed no significant concentration changes, which may suggest that sea mussels are unable to remove Cr from seawater quickly. The results suggest that it might be possible to use Mytilus sp. as a kind of biofilter for the improvement of seawater quality.