Limpets (Patella spp. Mollusca, Gastropoda) as model organisms for biomonitoring environmental quality

The use of limpets of the genus Patella as indicators of environmental quality is a priori promising, but few data are available in relation to their sensitivity to toxicants or their ability to accumulate pollutants. The aim of this work was to evaluate the use of Patella spp. as model organisms by (1) assessing the sensitivity of limpet embryos to some common pollutants, (2) validating the use of the limpet embryo-larval bioassay using natural sediment samples, and (3) analyzing the presence of pollutants by using Patella spp. as sentinel species. The obtained EC50 values ranged between 33 and 84 µg/L for Cu, 749–1163 for Cd, 317–1103 for Zn and 813–3411 µg/L for Pb; these sensitivity ranges were similar to those of other marine invertebrates used in ecotoxicology. It was not possible to validate the bioassay with natural samples, since the sampled sites did not cause significant toxicity. Patella spp. accumulated metals and organic pollutants in their soft tissues, showing higher concentrations than mussels for some metals (Cd, As and Cu) and lower concentrations for others (Hg, Zn, Cr), as well as for organic pollutants. Furthermore, bioaccumulation in limpets showed a spatial pattern of contamination similar to that shown by mussels and sediments, revealing limpets as a very good substitute/complement to mussels for biomonitoring marine pollution, especially in sites where mussel populations are absent or present at low numbers.