Effects of triclosan on reproductive prarmeters and embryonic development of sea urchin, Strongylocentrotus nudus

Abstract

Triclosan (TCS, 2,4,4′-trichloro-2′-hydroxydiphenyl ether), a broad-spectrum antibacterial agent, is commonly found in the aquatic environment. In this study, we investigated TCS toxicity with pertaining to gamete viability, fertilization, and embryogenesis up to pluteus stage of the sea urchin, (Strongylocentrotus nudus). When the sperm and eggs were exposed to TCS (0–3.0μM), the viability of sperm was significantly decreased at molarities higher than 1μM of TCS. In addition, for exposure of 2.0μM TCS the viability of eggs was not influenced and none of the sperm was viable. Fertilization rate was significantly decreased when sperm were exposed to 0.5 and 1μM of TCS (p<0.001) and no fertilization was observed for the exposure of 1.5μM of TCS. In embryonic development, embryos are treated with higher than 1.0μM levels of TCS displayed arrested development. For TCS, the EC50 and LOECs values were 1.8, 1.49 and 0.99μM and 0.53, 0.62 and 0.39μM for sperm viability, fertilization rate, and larval development to pluteus, respectively. In the recovery test regarding normal development of arrested embryos based upon TCS exposure time, it was observed that embryos exposed to 1μM TCS for 15h were normally recovered for normal development, while embryos with more than 30h exposure were not recovered to normal larvae. Overall, the results of this study strongly suggest that the gametes and embryos of S. nudus can provide the basis for an effective bioassay, with a fast and sensitive means of evaluating TCS contamination in the marine ecosystem.