Thesis and dissertation

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Browsing Thesis and dissertation by Author "BAKARI, Salama Juma"

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    IMPOSEX AND TBT LEVELS IN SELECTED MARINE GASTROPODSALONG THE COASTLINES OF ZANZIBAR
    (SUZA, 2020-10-01) BAKARI, Salama Juma
    Tributyltin (TBT) is one of the organ tin compounds species widely used as antifouling agent for paint in shipping industry to prevent fouling organisms.TBT is highly toxic antifouling compound deliberately introduced to marine environments with subsequent effects to non-targeted marine lives, especially imposex of gastropods. A good number of developing countries TBT still use as effective gradient in antifouling paints. Despite the fact that the International Maritime Organization (IMO) banned the global use of organotin compound as antifouling paints since 2008. The objective of this study was to analyze imposex levels of marine gastropods species as a bioindicator of TBT contamination along the coastal areas of Zanzibar. The results of this study show that Morulla granulate and Nassarius corronatus are more TBT sensitive species (showed significant imposex) compared to other gastropod species. Imposex results showed that Malindi station had average of 0.22 at stage 0-1a while Maruhubi station had average of 0.89 at stage 0-3c. Relative higher levels of TBT were detected at Malindi (10.2μgSn/kg) Forodhani (9.5μgSn/kg) and Kizingo (8.5 μg/Sn/kg) dry weight whilst lower level was detected at Beit el Raas station(0.35μgSn/kg dry weight). This study provides important information on imposex occurrence of local available gastropods along the coasts of Zanzibar which is a promising bioindicator for TBT contamination incoastal waters in the WIO region.