In vitro acute toxicity of anionic surfactant linear alkylbenzene sulphonate (LAS) on the motility of gilthead (Sparus aurata L.) sperm

This paper describes the acute toxicity of a known anionic surfactant, Linear Alkylbenzene Sulphonate (LAS), on the quality of gilthead Sparus aurata L. sperm. The parameter used to judge exposure effectiveness was sperm motility as well as its fertilizing ability after being combined with unexposed gilthead eggs. Preincubation of sperm suspensions with concentrations of LAS of 0.1, 0.5, 1, 2 and 4 mg/L caused decrease in sperm motility and fertilizing ability. In this respect, percentages of motile sperm were respectively 89.8+/-9.8, 81.7+/-16.3, 69.5+/-21.3, 57.1+/-19.1 and 21.2+/-10.9%. With regard to the percentage of fertilization success, the results were 85.7+/-8.1, 75.1+/-20.2, 62.9+/-19.7, 52.7+/-19.2 and 14.2+/-7.9% respectively. At concentrations of LAS of 0.5 mg/L or higher, the differences in both percentage of motility and fertilizing ability with controls were significant (p<5%). Although extrapolation from the laboratory to the field requires caution, the results of this work demonstrated that low-level surfactant pollution may impact directly on reproduction of the free gametes (sperm) released into water. It may lead to a long-term decline and eventual extinction of gilthead populations in nature when they are located close to effluents that are either untreated or receive inadequate secondary treatment. It is also quite important because this species constitutes an important link in the food chain and its death via exposure to surfactants may imbalance the littoral ecosystem.