Sources of variation in the assimilation of lead by a common gastropod sentinel Cantareus aspersus

► Lead concentrations in C. aspersus fail to detect assimilation differences between populations. ► The mass of Pb accumulated in the snails varies with growth rate and dietary composition. ► Variation in assimilation efficiency may reflect local adaptations to metal availability. ► As sentinels these present difficulties comparing sites or measuring general bioavailability.