Environmental Engineering Reference
In-Depth Information
trations of 100 ng L -1 TBT and TPT caused significant spermatogenesis in
ovaries of exposed abalone Haliotis gigantean ,whichresemblesgastropod
imposex [194]. On the other hand, testosterone accumulation was suggested
to be a reaction to the inhibition of androgen excretion due to a decrease in
sulfur conjugation of androgens [195]. A two-generation reproductive study
of TBT showed that the male reproductive system of rats is also affected.
Testis weights, spermatid and sperm count were reduced at 125 mg kg -1
TBT [196]. The data in fish and mammals indicates that TBT has androgenic
activity to different biota in addition to inducing imposex in gastropods.
6
Conclusions
The ongoing use of TBT-containing antifouling paints on large vessels leads
to contamination of harbors, ports and marine environments with high ship-
ping activities even today. Regulations for recreational boats resulted in a de-
crease of TBT levels in marinas, but it had a slow or marginal effect in coastal
waters. Both decreases in TBT-containing antifouling paints and the lack of
decreases have been reported in the literature. Organotins persist particularly
in sediments and biota. Along coasts, levels had not significantly decreased
even 10 years after regulations came into force. The widespread contamina-
tion found also in coastal regions of developing countries, in the open oceans
and deep seas (particularly in sediments and biota) demonstrates the global
occurrence of butyltins. The high toxicity, persistence and bioaccumulation
of TBT are of particular environmental concern. Recently androgenic activ-
ity of TBT in molluscs, fish and mammals was reported, indicating important
endocrine activity. The global occurrence of imposex in a large number of
gastropod species and associated population declines in coastal areas empha-
sizes the hazards and risks associated with these antifouling paints. The use
of TBT by commercial watercraft continues to contribute to the TBT load in
aquatic systems. The problem can only be solved by a global regulation and
ban of organotin-containing antifouling paints on ships and in aquaculture.
References
1. Alzieu C (2000) Ecotoxicology 9:71
2. Bryan GW, Gibbs PE, Hummerstone LG, Burt GR (1986) J Mar Biol Ass UK 66:611
3. WHO (1990) Tributyltin compounds. World Health Organization, Geneva, Switzer-
land
4. Fent K (1996) Crit Rev Toxicol 26:1
5. Alzieu C, Héral M, Thibaud Y, Dardignac MJ, Feuillet M (1982) Rev Trav Inst Peches
Marit 45:101
6. Alzieu C, Sanjuan J, Deltreil JP, Borel M (1986) Mar Pollut Bull 17:494
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