Barnacles: Possible indicators of zinc pollution?

Barnacles Balanus balanoides (L.), Elminius modestus Darwin, Lepas anatifera (L.)] from several different sites were found to accumulate the heavy metal zinc. The majority of the zinc was deposited in the tissues associated with the gut, and the level of zinc in soft body tissue generally reflected well the level of zinc in the immediate sea-water environment. The zinc accumulated in the gut tissues was in the form of discrete granules, mainly within the parenchyma cells which surround the gut. These granules probably exist as an insoluble zinc salt. A comparison of the zinc level in barnacles with those recorded for some other marine organisms indicates the possible usefulness of barnacles as indicators of zinc pollution.