Sea urchin gametes, embryos and larvae can be used for quick, cheap and reliable screening and testing of pharmacologically active substances and pollutants. Effects of fecal pollution of Kotor Bay water and mercury in sediments and water of Risan Bay on embryonic development of spotted sea urchin (S. granularis), were examined. The results showed malformations, blockade of adhesion blastomeras and normal embryonic development. This distortion of development is about the suppression of the normal process of cortical granule exocytosis during activation reaction that starts fertilization, response Ring wave and increased level of free calcium ions in intimately membrane layer.

The widespread use of rare earth elements (REEs) in a number of technological applications raises unanswered questions related to REE-associated adverse effects. We have previously reported on the multiple impact of some REEs on the early life stages of the sea urchin Paracentrotus lividus. The present investigation was to evaluate REE toxicity to early life stages in two unrelated sea urchin species, Sphaerechinus granularis and Arbacia lixula. The comparative toxicities were tested of seven REEs, namely yttrium, lanthanum, cerium, neodymium, samarium, europium and gadolinium as chloride salts at concentrations ranging from 10⁻⁷ to 10⁻⁴ M. The evaluated endpoints included developmental defects and cytogenetic anomalies in REE-exposed embryos/larvae, and decreased fertilization success and offspring damage following sperm exposure. The results showed different toxicity patterns for individual REEs that varied according to test species and to treatment protocol, thus showing toxicity scaling for the different REEs. Further, the observed effects were compared with those reported for P. lividus either following embryo or sperm exposures. S. granularis showed a significantly higher sensitivity both compared to A. lixula and to P. lividus. This study provides clear-cut evidence for distinct toxicity patterns among a series of REEs. The differences in species sensitivity at micromolar REE levels may warrant investigations on species susceptibility to impacts along polluted coasts.

Sea urchin gametes, embryos and larvae can be used for quick, cheap and reliable screening and testing of pharmacologically active substances and pollutants. The results obtained are in many cases applicable to mammals including humans.