Gastropod molluscs as indicators of the cadmium natural inputs in the Canarian Archipelago (Eastern Atlantic Ocean)

Abstract

Nowadays, gastropod molluscs are being utilized more and more as bioindicator organisms. Similarly, harmful metals on human health such as cadmium have been widely studied. The Canarian Archipelago (specifically the eastern islands) is constantly bathed by the African coastal upwelling, provoking oceanographic and biological differences between the islands. This process could assume an increase in the Cd concentration in their coastal waters and in the biota. Thus, in order to assess this fact, we measured cadmium concentrations in the soft parts of two species of limpets (Patella rustica and Patella candei crenata) and in a topshell snail (Osilinus atrata). Metal determination was performed using atomic absorption spectrometry (AAS). We found significant differences for metal concentrations between the eastern islands and the western islands for all species. P. rustica, P. c. crenata and O. atrata presented values ranging from 7.71, 2.11 and 7.56 µg g -1 dry wt. (eastern islands) to 1.38, 0.4 and 1.08 µg g -1 dry wt. (western islands) respectively. Therefore, we concluded that limpets and topshell snails seem to be suitable indicators of the cadmium concentrations in the coastal waters of the Canary Islands.

The gastropodOsilinus atrataas a bioindicator of Cd, Cu, Pb and Zn contamination in the coastal waters of the Canary Islands

“…In fact, top-shell snails have been considered efficient accumulators of Cd [4]. Therefore, the high levels of Cd recorded in the eastern islands (especially in Alegranza) may be a response to the upwelling process that takes place on the northwest coast of Africa, as Ramírez suggested previously [17]. The upwelling waters mainly reach the eastern islands of the archipelago [48], where Cd concentrations are higher than in the western islands [49].…”

“…Mussel Watch) [8], gastropod molluscs like patellid limpets or top-shell snails are increasingly employed in a similar role [4,[9][10][11][12][13]. In particular, studies to identify biomonitors of heavy metal contamination in the Canary Islands are scarce and incomplete [14][15][16][17][18]; they have focused on patellid limpets and top-shell snails harvested for human consumption, because bivalve molluscs (i.e. oysters or mussels) are rare and occur only in small areas in the archipelago.…”