## 3 Results
MPI values of the shells and shell extracts at all three sites were lower than 1. Comparing location differences across the same sample groups, the highest contents of Zn (135 \(\mu\)g g\({}^{-1}\)), Pb (1.16 \(\mu\)g g\({}^{-1}\)), and Cd (0.73 \(\mu\)g g\({}^{-1}\)) were found in the soft tissues of mussels from Cogi, while Cu (3.53 \(\mu\)g g\({}^{-1}\)), Fe (35.4 \(\mu\)g g\({}^{-1}\)) and Hg (0.095 \(\mu\)g g\({}^{-1}\)) contents were the highest in IMB soft tissues. Manganese concentrations were almost identical for Cogi (3.63 \(\mu\)g g\({}^{-1}\)) and IMB samples (3.62 \(\mu\)g g\({}^{-1}\)), and both were higher than that in the soft tissues of Sv. Nedjelja mussel samples. Conversely, _conchixes_ from Sv. Nedjelja mussels had the highest concentrations of Cu (15.8 \(\mu\)g g\({}^{-1}\)), Fe (68.3 \(\mu\)g g\({}^{-1}\)), Pb (1.22 \(\mu\)g g\({}^{-1}\)), and Hg (0.168 \(\mu\)g g\({}^{-1}\)). Shells from Cogi had the highest Cu (11.6 \(\mu\)g g\({}^{-1}\)), Fe (0.81 \(\mu\)g g\({}^{-1}\)), and Mn (2.57 \(\mu\)g g\({}^{-1}\)) concentrations. Furthermore, the extracts from Cogi had the highest Zn (12.7 \(\mu\)g g\({}^{-1}\)) and Fe (4.82 \(\mu\)g g\({}^{-1}\)) concentrations, while Cu (2.14 \(\mu\)g g\({}^{-1}\)) and Mn (1.62 \(\mu\)g g\({}^{-1}\)) contents were the highest in extracts from the IMB. Figure 5 presents PCA and CCA plots of trace metal concentrations in four different media (shell, soft tissue, _conchix_, and shell extract) of _M. galloprovincialis_ L. sampled from Sv. Nedjelja (S), Cogi (C), and the IMB (I). PCA analysis showed similarities in trace metal accumulation in all media except _conchix_. However, the _conchix_ sample from Cogi (OC) was slightly similar to extracts from the IMB and Sv. Nedjelja mussels. According to CCA analysis, _conchixes_ are grouped around Cu, Fe, and Hg, while Cd and Zn are in correlation with soft tissues. Moreover, the shells are in correlation with Mn, although the highest Mn concentrations were found in the soft tissues (Table 1). \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline
**Trace** & & & & & & & & & & & & \\
**Metals** & & & & & & & & & & & & \\
**(\(\mu\)g g\({}^{-1}\))** & **KS** & **KC** & **KI** & **TS** & **TC** & **TI** & **OS** & **OC** & **OI** & **ES** & **EC** & **EI** \\ \hline
**Zn** & 11.6 & 11.6 & 11.0 & 125 & 135 & 104 & 7.85 & 13.6 & 7.59 & 5.3 & 12.7 & 4.15 \\
**Cu** & 2.09 & 3.91 & 2.74 & 2.93 & 3.39 & 3.53 & 15.8 & 11.0 & 12.6 & 2.02 & 1.05 & 2.14 \\
**Fe** & 0.69 & 0.81 & 0.64 & 21.0 & 11.0 & 35.4 & 68.3 & 21.6 & 40.8 & 3.92 & 4.82 & 3.86 \\
**Mn** & 2.44 & 2.57 & 2.31 & 2.78 & 3.63 & 3.62 & 2.07 & 1.60 & 2.80 & 1.51 & 1.48 & 1.62 \\
**Pb** & \(<\)0.25 & \(<\)0.25 & 0.31 & 0.54 & 1.16 & 1.06 & 1.22 & \(<\)0.25 & \(<\)0.25 & \(<\)0.25 & \(<\)0.25 & \(<\)0.25 \\
**Cd** & \(<\)0.03 & \(<\)0.03 & \(<\)0.03 & 0.69 & 0.73 & 0.41 & 0.06 & 0.067 & \(<\)0.03 & \(<\)0.03 & \(<\)0.03 \\
**Hg** & \(<\)0.001 & \(<\)0.001 & \(<\)0.001 & 0.077 & 0.065 & 0.095 & 0.168 & 0.100 & 0.145 & \(<\)0.001 & \(<\)0.001 & \(<\)0.001 \\
**MPI** & 0.258 & 0.291 & 0.297 & 2.319 & 2.711 & 2.929 & 2.158 & 1.214 & 1.163 & 0.275 & 0.291 & 0.269 \\ \hline \end{tabular}
\end{table} 
Table 1: Trace metal concentrations and metal pollution index (MPI) within the group of _M. galloprovincialis_ L. specimens sampled from Sv. Nedjelja (S), Cogi (C), and the IMB (I) in the shell (KS, KC, KI), soft tissue (TS, TC, TI), _conchix_ (OS, OC, OI), and shell extract (ES, EC, EI).