Imposex in marine gastropods from the Atlantic coast of South Africa

ROOS, N.; AVERBUJ, A.; BOWMANN, H.

Arnsiton

Congreso; Southern African Society of Aquatic Scientists; 2013

Southern African Society of Aquatic Scientists

TBT is an organotin compound (OTC) used as an antifouling agent in paint that is applied to the hulls of vessels to prevent the formation of biofilms. This highly toxic antifouling compound leaches into the water and subsequently has various negative effects on marine life, especially marine gastropods. One of the most serious effects of exposure to TBT is the growth of a penis/vas deferens in female gastropods; this phenomenon is referred to as imposex. Marine gastropods are useful bioindicators as imposex is related to TBT exposure. It may affect the reproduction of these organisms and thus affect coastal ecology. The consumption of TBT-contaminated foodstuffs may also pose a risk to human health. The use of antifouling paints containing organotin compounds such as TBT still continues in developing countries, despite the fact that the International Maritime Organization (IMO) banned the global use of organotin compounds (OTCs) in antifouling paints applied to ships in 2008. This study assessed the current state regarding TBT-induced imposex in marine gastropods along the Atlantic coastline of South Africa by collecting caenogastropods from sites based on presumed high and low impacts of TBT activity and using various indexes: the Relative Penis Length Index (RPLI), Relative Penis Size Index (RPSI), Male:Female ratio (M:F), Percent Imposex (% I). The first cases of imposex have been found. The results of the assessment will be made available to interested and affected parties and may in turn generate the need for protective measures.