# Organochlorines Accumulation in Caged Mussels
## 4 Discussion  
### Accumulation of OCs  
A similar finding to our results was observed by [PERSON] et al. [23], who reported 9.27- and 6.1-fold increases of PCBs and 14.6- and 2.08-fold increases of _p,p'_-DDTs in blue mussels during an 8-week exposure in two different ways. Translocation of mussels _Mytilus trossulus_ to the Gulf of Gdansk revealed up to a 2-fold increase of PCB7, DDT, and its derivatives levels during an 8-week period [10]. Bimonthly accumulation of target contaminants in this study, according to one-way ANOVA analysis (p \(<\) 0.05), indicated mostly no significant temporal differences in tissue levels of 1- and 2-year-old mussels except for lindane (p = 0.000 *), heptachlor (p = 0.041 *), _p,p'_-DDT (p = 0.022 *), CB 28 (p = 0.001 *), CB 105 (p = 0.009 *), and CB 180 (p = 0.015 *) (Table 1). Seasonal variations of contaminants in mussel tissue most likely originate from variability in environmental parameters such as temperature and food availability [24; 25]. Another source of contaminants for biota could be sediment and its resuspension [1; 10], which is controlled by the prevailing circulation in the Bay, mainly induced by wind [20]. OC concentration in mussels sampled from Kastela Bay was mostly positively related to shell length both for 1- and 2-year-old mussels. Regarding shell length, 1-year-old mussels revealed significant relationships with CB 101, CB 138, CB 153, CB 180, and CB 194, while 2-year-old mussels had a significant relationship only with CB 180, showing a poor relationship with chlorinated pesticides. The majority of OCs were positively related to the tissue weight of 1- and 2-year old mussels, pointing to a significant correlation with HCB, CB 118, and CB 180 in 2-year-old mussels. Moreover, there was a significant relationship between temporal variations of CI and lipid content, both for 1-year-old (r = 0.465 *) and 2-year-old (r = 0.552 *) mussels. Concerning seasonal changes of CI and lipid content in relation to seasonal changes of chlorinated hydrocarbon contents in mussel tissue, no correlation of their changes was established for the 1-year-old species. Regarding the 2-year-old species, a significant relationship was observed between CI and congener CB 118 (r = 0.703 *) and CB 156 (r = 0.482 *). Moreover, concentrations of \(p\),\(p^{\prime}\)-DDE, CB 28, CB 52, and CB 105 in the tissue of the 2-year-old species increased significantly with EOM content increase (Table 2). A lack of apparent statistical correlations among biological parameters and contaminant concentrations in this research can be attributed to the selection of the initial species, regarding the age and size of mussels. The significance of the biological parameters' influence differs depending on the sampling location and its contamination level [12; 21; 26; 27; 28]. In the case of the shallow Kastela Bay, the effect of environmental factors may prevail over the effect of biological factors that change over a longer time scale. This particularly refers to the changes in chlorinated hydrocarbon bioavailability in the Bay. As mussels are fed by the continual filtering of seawater, the gills have a key role in ensuring a constant supply of nutrients. The intake of chlorinated hydrocarbons from suspended organic matter is much more important than direct uptake from water since the amount of lipophilic contaminants in the soluble phase of seawater is very low [18]. One-way ANOVA analysis and posthoc [PERSON]'s test suggest significant spatial differences in OC accumulation in mussels between study areas (Table 1). The levels of CPs and PCBs were the highest at S1 due to intensive contaminant inputs by industrial and urban wastewaters, biological activity, and sediment resuspension in that area. The intensity of environmental parameters at other stations was lower, mostly revealing a decreasing counterclockwise direction influenced by wind-induced circulation in the Bay [20].