Toxicity of tri-n-butyltin to sea urchin eggs and larvae: Relation to bioaccumulation at the nanomolar level

Nanomolar concentrations of tri-n-butyltin (TBT) from 5 x 10(-10) M to 5 x 10(-9) M, were assayed on sea urchin (Paracentrotus lividus) egg cleavage a nd on larval development. Preincubation enhanced TBT toxicity to first clea vage DNA and protein syntheses but not to intracellular calcium sequestrati on. Exposure to nanomolar TBT affected the larval development up to the nin th day by reducing arm length and increasing the diameter of the rudiment. Chromatographic analysis of TBT in eggs shows a dose-dependent biomagnifica tion with a half-time of 5 min, which is much shorter than the length of pr eincubation necessary to provoke cytotoxicity at the same concentration (5 x 10(-9) or 5 x 10(-10) M). Our data suggest that nanomolar concentrations of TBT similar to those Encountered in polluted waters could directly affec t sea urchin egg development after fertilization and the larval cycle, thes e effects bring independent of bioaccumulation.