Effects of exposure to gadolinium on the development of geographically and phylogenetically distant sea urchins species.

Gadolinium (Gd), a metal of the lanthanide series used as contrast agent for magnetic resonance imaging,is released into the aquatic environment. We investigated the effects of Gd on the development of foursea urchin species: two from Europe, Paracentrotus lividus and Arbacia lixula, and two from Australia,Heliocidaris tuberculata and Centrostephanus rodgersii. Exposure to Gd from fertilization resulted in inhibitionor alteration of skeleton growth in the plutei. The similar morphological response to Gd in thefour species indicates a similar mechanism underlying abnormal skeletogenesis. Sensitivity to Gd greatlyvaried, with the EC50 ranging from 56 nM to 132 mM across the four species. These different sensitivitieshighlight the importance of testing toxicity in several species for risk assessment. The strong negativeeffects of Gd on calcification in plutei, together with the plethora of marine species that have calcifyinglarvae, indicates that Gd pollution is urgent issue that needs to be addressed.