Trematode parasite influence on copper, iron and zinc content of polluted Littorina littorea: infection, host sex and time effects

Temporal variations in copper, iron and zinc levels in the periwinkle, Littorina littorea, were investigated to determine whether levels were affected by the sex of the organisms and/or by the presence of two species of trematode parasite. Significant monthly changes in concentrations of all these metals were found, with levels varying according to periwinkle sex and parasite infection. Periwinkles infected by either Cryptocotyle lingua or Renicola roscovita had reduced copper and iron concentrations compared to same-sex uninfected periwinkles, although infected periwinkles generally contained higher concentrations of zinc. Periwinkles infected by the more invasive C. lingua rediae had lower copper concentrations than those infected by R. roscovita sporocysts. These results clearly indicate that in areas of high parasite prevalence L. littorea is not an ideal metal-biomonitor.