The effect of digenean (Platyhelminthes) infections on heavy metal concentrations in Littorina littorea

This study examined the inter-relationships, between molluscs, heavy metal concentrations and trematode parasites, Littorina littorea (Mollusca: Gastr opoda) were sampled seasonally from two sites in a tidal lagoon. Site A was close to the inflow of a polluted stream whilst site B was at the opposite end of the lagoon. The samples were analysed for lead, iron, copper and ni ckel. Metal concentrations in L. littorea varied with site. season and para site infection, and exceeded comparative nonpolluted concentrations for all metals in some samples. Parasitized periwinkles consistently had significa ntly lower levels of iron, copper and nickel than uninfected periwinkles.