CHAPTER 10 • Occurence, Pathways and Bioaccumulation of Organometallic Compounds
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tumn. Even if seasonal variation in concentrations was detected, the speciation was
not greatly different from summer to winter, TBT being prevalent in all seasons, both
in gills and digestive glands.
The obtained data allowed us to draw some preliminary observations on relationships between butyltin trends in sea water and in mussel tissues. TBT and DBT trends
showed the best correlation between seawater and gill levels. Therefore, this organ is
the most suitable to be considered as bioindicator of organotin seasonal variations.
Moreover the gills showed the highest TBT concentration factors (dry tissues/water),
which was estimated at 9500. In winter a TBT minimum was found both in sea water
and in tissues. Looking at speciation, it is interesting to point out that in seawater
Fig. 10.7. Butyltin compounds
TBT
partitioning (0/0) between dis100
solved (grey) and particulate
(dark grey) phases
80
60
40
20
0
100
80
60
40
20
0
MBT
100
80
60
40
20
0
lui
Sep
Oct
Dec
Feb
May