## 3 Results
### Latitude, Depth and Sampling Year Effect in Mediterranean Mussel
#### 3.3.2 Tyrrhenian  
Summary statistics on each variable included in the correlation analysis on data from the Tyrrhenian Sea are reported in Table 5.  
As [PERSON]'s rank correlation revealed, after removing the effect of the sampling depth and sampling year, concentrations of LMW-, MMW- and HMW PAHs in Mediterranean mussel caught in the Tyrrhenian Sea increase with latitude in both cold and warm periods,  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Period** & **PAHs Class 1** & **C\({}_{mm}\) 2** & **C\({}_{min}\) 3** & **C\({}_{max}\) 4** & **Depth\({}_{min}\) 5** & **Depth\({}_{mm}\) 6** & **Year\({}_{min}\) 7** & **Year\({}_{min}\) 8** & **Lat\({}_{min}\) 9** & **Lat\({}_{max}\) 10** \\ \hline \multirow{3}{*}{Autumn/Winter} & LMW & 0.00463 & 0.0002 & 0.18090 & 1.20 & 24.80 & 2006 & 2009 & 41.60 & 45.76 \\  & MMW & 0.00591 & 0.00015 & 0.11010 & 1.20 & 24.80 & 2005 & 2009 & 41.60 & 45.76 \\  & HMW & 0.00382 & 0.00002 & 0.34500 & 1.20 & 24.80 & 2005 & 2009 & 41.60 & 45.76 \\ \hline \multirow{3}{*}{Spring/Summer} & LMW & 0.01093 & 0.00000 & 1.15500 & 0.01 & 35.00 & 2006 & 2011 & 40.20 & 45.77 \\  & MMW & 0.00396 & 0.00003 & 0.03780 & 0.01 & 30.60 & 2005 & 2017 & 40.20 & 45.77 \\  & HMW & 0.00209 & 0.00000 & 0.03150 & 0.01 & 30.60 & 2005 & 2017 & 40.20 & 45.77 \\ \hline \hline \end{tabular}  
* _PAHs class_—class of PAHs based on molecular weight, 2 \(C_{mm}\)—mean concentration, 3\(C_{min}\)—minimum concentration, 4\(C_{mm}\)—maximum concentration, 5\(Depth_{min}\)—minimum sampling depth, 6\(Depth_{max}\)—maximum sampling depth, 7\(Year_{min}\)—year of the first sampling campaign, 8\(Year_{max}\)—year of the last sampling campaign, 9\(Lat_{min}\)—minimum latitude of sampling sites, 10\(Lat_{max}\)—maximum of sampling sites.  
Footnote 9: \(Lat_{min}\)—minimum latitude of sampling sites, 10\(Lat_{max}\)—maximum of sampling sites.  
\end{table}
Table 4: Summary statistics on LMW (low molecular weight), MMW (middle molecular weight) and HMW (high molecular weight) PAHs in Mediterranean mussels caught in different seasons along the Italian coast of the Adriatic Sea. Concentrations are in mg/kg wet weight; sampling depth is in meters; latitude are in decimal degrees. Reported statistics were calculated after missing-data removal from concentration, sampling depth, sampling year and latitude columns.  
and this increase is statistically significant (\(p<0.05\)) for every PAH class and period of the year, excluding MMW PAHs.  
In Mediterranean mussel caught in the Tyrrhenian Sea, after removing the effect of the latitude and sampling year, concentrations of LMW in warm months and of MMW in both periods of the year are negatively correlated with the sampling depth. These results are always statistically significant (\(p<0.05\)), apart from those on MMW in cold months. On the contrary, in all other cases (i.e., LMW PAHs in cold months, and HMW PAHs in both periods of the year), the PAH concentrations and sampling depth turned out to be positively correlated, always reaching statistical significance, except for HMW PAHs in warm months.  
Finally, concentrations of LMW-, MMW- and HMW PAHs in Mediterranean mussels caught in the Tyrrhenian Sea, in both cold and warm months, increase over the years, and this trend is statistically significant (\(p<0.05\)) for LMW- and MMW PAHs in warm months, and for HMW PAHs in both periods of the year.