## Results
### Accumulation and Elimination of Free and Total MC by A. anatina  
Free MC were rapidly accumulated by _A. anatina_ as they were detected in tissues from the first day of exposure (Figure 2A). However, there were no significant differences in free MC concentration in _A. anatina_ tissues between the exposure concentrations (Kruskal-Wallis, \(p>0.05\)). Toxin contents in _A. anatina_ exposed to densities of filaments producing an equivalent of 1, 10 and 100 \(\upmu\)g MC/L increased from day one (respectively \(0.10\pm 0.10\); \(1.4\pm 0.55\) and \(0.7\pm 0.3\)\(\upmu\)g MC/g DW) to a maximum at day 14 of exposure for mussels exposed to 10 and 100 \(\upmu\)g MC/L (respectively \(9.9\pm 0.5\) and \(14.05\pm 4.3\)\(\upmu\)g MC/g DW) and at day 21 for those exposed to 1 \(\upmu\)g MC/L (12.0 \(\pm\) 5.0 \(\upmu\)g MC/g DW). During the deputation, the free MC contents in tissues decreased more rapidly in mussels exposed to a density of filaments producing an equivalent of 1 and 100 \(\upmu\)g MC/L, compared to those exposed to an equivalent of 10 \(\upmu\)g MC/L (Figure 2A). Total MC (Figure 2B) were detected in digestive glands of _A. anatina_ from the first day of exposure to the last day of deputation regardless of the exposure concentration. During the experiment, the mean percentage of bound MC in _A. anatina_ was \(70\pm 7\%\) during the exposure and \(74\pm 4\%\) during the deputation. During the exposure, the total MC contents in _A. anatina_ exposed to a density of filaments producing an equivalent 100 \(\upmu\)g/L were significantly higher than in mussels exposed to 1 \(\upmu\)g MC/L (Kruskal-Wallis, \(p<0.05\)). However, MC concentration in mussels exposed to a density producing an equivalent to 10 \(\upmu\)g MC/L did not differ significantly compared to the two other densities (Kruskal-Wallis, \(p>0.05\)). The maximum total MC accumulation was observed at day 21 of exposure in _A. anatina_ exposed to a density of filaments producing an equivalent of 1 \(\upmu\)g MC/L (\(23.4\pm 8.0\)\(\upmu\)g MC/g DW), and at day 14 of exposure in mussels exposed to a density of cyanobacteria producing an equivalent of 10 and 100 \(\upmu\)g MC/L (\(116.2\pm 36.5\)\(\upmu\)g MC/g DW and \(99.1\pm 22.1\)\(\upmu\)g MC/g DW respectively) (Figure 2B). During the deputation, MC concentrations in mussels exposed to an equivalent of 10 \(\upmu\)g MC/L were significantly higher compared to the two other exposure concentrations (Kruskal-Wallis, \(p<0.05\)), and no differences were observed between those exposed to 100 and 1 \(\upmu\)g MC/L (Kruskal-Wallis, \(p>0.05\)). Thus, no direct correlation between free and total MC concentration in digestive glands of _A. anatina_ and levels of water contamination were observed during the exposure nor during the deputation. Regarding the accumulation of total MC in the entire body of _A. anatina_ (Table 1), concentrations in the digestive gland were five times higher compared to whole individuals, a difference that was significant (Mann-Whitney test, \(p<0.01\)). However, total MC concentrations in whole individuals displayed important variability within the same pool of three mussels (Table 1). Additionally, total MC concentrations in whole _A. anatina_ did not differ significantly between densities during the experiment (Kruskal-Wallis, \(p>0.05\)).