Comparison of embryonic development and metal contamination in several populations of the sea urchin Sphaerechinus granularis (Lamarck) exposed to anthropogenic pollution

Over the past years the functional deficiencies observed in the sea urchin Sphaerechinus granularis from the Bay of Brest (France) have led us to sele ct several populations within this species to assess water quality in the B ay of Brest. The present study reports on the comparison of the quality of embryonic development and of the level of metal contamination in sea urchin gonads and gut wall in four populations. Three of them lived in the Bay of Brest, and the last one was considered a reference, being settled in the G lenan Archipelago in southern Brittany (France). The sea urchin population living at the mouth of the River Aulne, at the Armorique Point, seemed to b e the most affected, for it displayed the highest rate of blockage and the longest delay in embryonic development along with the highest concentration s in heavy metals, i.e., Fe, Cu, Pb, Cd, and Hg, in the gut wall and in the gonads. A comparison with previous data highlighted a degradation of healt h conditions in the population living at Marloux in the vicinity of Brest h arbor. The comparison of the metal levels detected in individuals from thes e two populations with the data reported in the literature allowed us to co nclude for a local contamination of the bay waters by Fe and Hg. In additio n, this study also revealed that Zn and Cd concentrations were sometimes hi gher than the maximum values reported in the literature and evidenced an in crease of contamination by Cu and Pb over the period of study; it should be noted, however, that these values were not excess levels. Our investigatio ns also suggest that Zn, Cd, Pb, and Cu levels should be monitored in the f uture.