sentences:  The preferred final hosts of "Pomphorhynchus laevis" include the chub, "Leuciscus cephalus" and barbel, "Barbus barbus" when in freshwater and the minnow, "Phoxinus phoxinus" when in an isolated body of water.Immature "P. laevis" are mainly found in the proximal part of the digestive tract while mature and developing "P. laevis" are found near the first intestinal loop with the posterior third loop of the digestive tract being uninhabitable.When chub ("Leuciscus cephalus") infected with "Pomphorhynchus laevis" are exposed to different concentrations of lead, the parasite is able to reduce lead concentrations in the host.