Accumulation of heavy metals in the Ligula intestinalis plerocercoids (Pseudophyllidea) of different age

The heavy metal (Pb, Cd, Cr, Ni) concentrations were evaluated in two age g roups (0+ and 1+; 2+ and older) of Ligula intestinalis plerocercoids from t he body cavity of two fish intermediate hosts (bream, Abramis brama; roach, Rutilus rutilus). Statistically highly significant lower concentrations of Pb, Cd and Cr were found in young plerocercoids as compared with older specimens. By contrast , concentrations of Ni were higher in younger plerocercoids. The accumulati on and increase of Pb, Cd and Cr concentrations in pseudophyllidean tapewor m plerocercoids is considered to be a gradual and long-term process, occurr ing probably during the whole growing phase of these parasites in the inter mediate host. Environmental influences of heavy metal accumulation are disc ussed.