Assessment of imposex and butyltin concentrations in Gemophos viverratus (Kiener, 1834), from São Vicente, Republic of Cabo Verde (Africa)
This work constitutes the first assessment of tributyltin (TBT) pollution levels in the Republic of Cabo Verde (Africa) and proposes the marine gastropod Gemophos viverratus (Kiener, 1834) as a new bioindicator of TBT pollution in the Macaronesia and west coast of Africa. Specimens were collected between August and October 2012 along a gradient of naval traffic in São Vicente Island. The results clearly indicate an increase of imposex levels (percentage of females affected with imposex, 0–100 %; vas deferens sequence index, 0–4.1; relative penis length index, 0–54.6 %) and female TBT contamination (from 5 to 37 ngSn g−1 dry weight (dw)) from outside to inside the harbour of Porto Grande Bay and identify this area as the focus of TBT pollution in the island. The butyltin degradation index for G. viverratus tissues ranged between 1.3 and 2.2, which being above 1 suggests that a considerable part of TBT inputs to the bay may not be very recent. Sterile females were found inside the harbour with an incidence up to 21.4 %. Considering the existence of a planktonic veliger stage in the life cycle of G. viverratus, it is expected that recruitment of newborn individuals can be supplied from unaffected breeding females inside and outside the Porto Grande Bay, resulting in a reduced impact of TBT pollution on population abundance. G. viverratus is very promising to be used as a simple, inexpensive and efficient novel tool for TBT pollution biomonitoring in the Macaronesia and west coast of Africa, a region for which there is an astonishing lack of information concerning levels and ecological impacts of TBT pollution.
KeywordsGemophos viverratus TBT pollution Organotins Imposex Cabo Verde Africa
The authors thank the valuable assistance of the MSc Felipe Ribas who illustrated the VDS scheme for G. viverratus presented in this work. This work was financially supported by the Portuguese Foundation for Science and Technology (FCT) through the program COMPETE and the project CESAM-PEst-C/MAR/LA0017/2013.
- ENAPOR (2013) Statistics. Port Grande. Portos de Cabo Verde. http://www.enapor.cv/portal/V10/EN/aspx/estatisticas/estatisticaPorto.aspx?id_linha=764&ms=0-5-17. Accessed 16 Dec 2013
- Nyarko E, Evans SM (1997) The impacts of tributyltin, pollution and human food gathering on populations of whelks Thais haemostoma and T. nodosa on the coast of Ghana. In: Evans SM, Vanderpuye CJ, Armah AK (eds) The coastal zone of West Africa: problems and management. Penshaw, Sunderland, pp 93–101Google Scholar
- Silva MNP (2005) Caracterização ambiental e proposta de gestão integrada para o litoral da cidade do Mindelo (S. Vicente – Cabo Verde). Dissertation, Universidade Nova de Lisboa (in Portuguese)Google Scholar
- Smith BS (1971) Sexuality in the American mud snail Nassarius obsoletus (Say). Proc Malacol Soc Lond 39:377–378Google Scholar
- Sousa A, Matsudaira C, Takahashi S et al (2007) Integrative assessment of organotin contamination in a southern European estuarine system (Ria de Aveiro, NW Portugal): tracking temporal trends in order to evaluate the effectiveness of the EU ban. Mar Pollut Bull 54:1645–1653. doi: 10.1016/j.marpolbul.2007.07.005 CrossRefGoogle Scholar