Chemistry and Fate of Organotin Antifouling Biocides in the Environment - Antifouling Paint Biocides - page 17

Chemistry and Fate of Organotin Antifouling Biocides
in the Environment

Iwao Omae
Omae Research Laboratories, 335-23, Mizuno, Sayama, 350-1317 Saitama, Japan
[e-mail]

1 I tr cti n ................................... 18

2 Organotin Compounds and Their Properties ................. 19

2.1 OrganotinCompounds ............................. 19

2.2 PropertiesofOrganotinCompounds ..................... 22

2.3 ToxicitiesofTriorganotinCompounds..................... 23

3 Degradation of Organotin Compounds .................... 27

3.1 OrganotinCompoundsasIdealAntifoulants ................. 27

3.2 Degradation of Organotin Compounds

byHydrolysis,UltravioletLightandMicroorganisms ............

27

3.3 Half-livesofOrganotinCompoundsinSeawaterandSediment ....... 34

4 Bioaccumulation and Sediment Accumulation of Organotin Antifoulants . 37

5 Biomethylation of Organotin Compounds .................. 38

6 Degradation of Organotin Compounds

by Organisms and Their Metabolites

..................... 41

7 cl si s ................................... 45

References ....................................... 46

Abstract Organotin antifouling paints are degraded relatively rapidly in seawater mainly
by microorganisms, but they have high affinities to sediment and organisms in the sea.
The concentrations of tin in seawater have been observed to decrease in many harbors in
the world since the ban to use the paints for small vessels came into force, however, in
a few areas frequented by large ships, organotin compounds continued to be input onto
the surface of the sediment. Therefore, recently, the number of articles on the investiga-
tion of depuration of organotin compounds by organisms have increased. For example,
pyroverdins, azotochelin and ornibactin obtained from microorganisms such as Pseu-
domonas chlororaphis and Burkholderia cepacia , and organisms such as dinoflagellates,
diatoms, mussel, green algae and chrysophytes are able to depurate organotin compounds
of TBT and TPT in seawater. Furthermore, with the help of these depuration technologies,
we hope that the marine environment will improve in the world, at least up to the point in
time where environmentally friendly best alternative antifouling paints are used routinely
for all vessels.

Keywords Bioaccumulation · Biomethylation · Degradation · Fate ·
Organotin antifouling biocides