Bioaccumulation of Some Heavy Metals in the Liver Flukes Fasci¬ola hepatica and F. gigantica

Heavy metals tend to bioaccumulate in living organisms, and their accumulation has been a major concern. As mammals are known to excrete heavy metals via their bile, it seems to be very promising to analyse metal burdens of para­sites that infect the biliary tree such as liver flukes of the genus Fasciola. The present study was carried out to evaluate F. hepatica and F. gigantica as bioaccumula­tors of heavy metals, and to estimate their use as sensitive markers of environmen­tal pollution with heavy metals. A total of 36 slaughtered buffaloes (26 infected and 10 controls) col­lected from the slaughter-house of Tanta City, Egypt were used. Samples of muscle and liver tissues were taken from each buffalo. A total of 44 adult Fasciola flukes were collected from the 26 infected buffaloes. Quantification of some heavy metals (Cd, Cr, Cu, Pb and Zn) in samples was carried out using electrothermal atomic absorption spectrometry. Results revealed different concentrations of heavy metals in different host tissues. The adult flukes were classified into F. hepatica (n = 25) and F. gigantica (n = 19). The bio-concentration factor (BCF) of Cr was significantly higher in F. hepatica (P = 0.0465) while BCF of Zn was significantly higher in F. gigantica (P = 0.0189). A comparative study between the two species as regards the BCF was never done before. The obtained results indicate the possibility of use of Fasciola flukes as markers of environmental pollution with some heavy metals.