Environmental Engineering Reference
In-Depth Information
Scheme 3
Speculated pathway of TBT chloride metabolism [64]
The acute oral toxicity of TBT chloride in rats (LD
50
)is122-349 mg TBT
kg
-1
body weight (see Table 3). However, mammals such as rats are able to
metabolize a small amount of TBT compounds. For example, Wister rats,
which are orally administrated at a dose of 2 mg TBT kg
-1
body weight after
12 h of fasting, were investigated for 7 days and
n
-butyl(3-carboxypropyl)tin
compound in the liver and
n
-butyl(3-hydroxybutyl)tin compound in the kid-
ney were found as the main metabolites, respectively. Matsuda et al. spec-
ulated the pathway for progressive removal of the organic groups from tin
atoms as shown in Scheme 3 [64].
The depuration of TBT with mussel,
Mytilus edulis
was determined by
the analysis of dissected organs. A transplant study showed that the depu-
rations of TBT from gill tissue and digestive gland tissue are biphasic two-
compartment processes involving a rapid TBT loss process and a concurrent
slowerTBTdepurationprocessasshowninTable7[65].Whole-bodyandgo-
nadal tissue depuration followed a slower monophasic depuration process.
Depuration half-life values range from 2.2-5.3 days for the fast depuration
component and 28-69 days for the slow component [65].
Table 7
Half-life values for TBT and DBT depuration from various tissues in mussels [65]
Tissue
TBT rapid
TBT slow
DBT
T
1
/
2
(day)
T
1
/
2
(day)
T
1
/
2
(day)
Whole animal
-
69
115
Gonad
-
28
58
Digestive gland
5.3
58
35
Gills
2.2
53
36
