Environmental Engineering Reference
In-Depth Information
14 C-labeled triphenyltin acetate, TBTO, TBT fluoride and TPT chloride in
soil could be broken down to inorganic tin; since carbon dioxide was evolved,
and since as a similar breakdown did not occur in sterile soil, the degra-
dation was ascribed to the ability of certain microorganisms to metabolize
the organotin compounds [24, 52-55]. Gram-negative bacteria Pseudomonas
aeruginosa and Alcaligenes faecalis and green alga, Ankistrodesmus faecalis
are reported as deakylation organisms [56, 57].
Sheldon [55] reported the breakdown of 14 C-labeled TBTO in soil and
showed that its degradation occurred faster under aerobic rather than anaer-
obic conditions.
Mussels are used as biomonitors to evaluate the concentrations of the
organotin compounds in Dutch fresh water at two locations near potato crops
that were sprayed with TPT at the end of the summer of 1992 [58]. The
half-life times in the field were calculated to be 100 to 200 days for TPT as
shown in Table 6 [58-62]. TBT is more easily depurated by zebra mussels than
TPT [58].
The biodegradation of TBT and DBT in unfiltered seawater in sum-
merisratherfast;theirhalf- ivesareaboutaweek.Butpretreatment
with a glass fiber filter makes the half-life of TBT much longer (about 80
days) [63].
The organotin compounds are mainly degraded by microorganisms, and
this is the depuration of organotin compounds by organisms. This depuration
can be done not only by microorganisms but also by many other organisms
such as mussels, fish and mammals under not so high concentrations of the
organotins.
Table 6 Uptake and depuration rate constant of TBT and TPT for the zebra mussel ( Dreis-
sena polymorpha ) and other organisms [58-62]
Compound
Organism
Study type
T 1 / 2 (day)
Refs.
TPT
Dreissena polymorpha
field
200
±
89
[58]
Dreissena polymorpha
±
TPT
field
105
49
[58]
26 a
TBT
Dreissena polymorpha
field
[59]
lab (18 C)
2-14 a
TBTO
Mytilus edulis
[60]
133 a
TPT
Mytilus edulis
field
[61]
lab (22 C)
TPT
Poecilia reticulate
49
[61, 62]
a T 1 / 2 was calculated after transplantation to a clean area by Becker van Slooten and
Tarradellas [59]. In another study by Laughlin et al. [60], the animals were transplanted
from the field to laboratory aquaria for elimination studies. In a study by Shiraishi and
Soma [61], the mussels were not transplanted, but the decrease in body concentrations,
after the legal restriction on TPT application, was investigated
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