During the ecological study of 45 specimens of bleak (Alburnus alburnus (Linnaeus, 1758)) by applying standard techniques for parasites in ten specimens of fish an infestation was found with the acantocephalan Pomphorhynchus laevis. Aim of the present study is to establish the content of arsenic in water, sediments, tissues and organs of A. alburnus and its parasite Pomphorhynchus laevis, and the impact that the acanthocephalan has on the content of arsenic in his host tissues and organs. From the tissues and organs of the studied specimens of Alburnus alburnus, the content of arsenic in samples of liver were higher than in the samples of muscles and skin, and ranged as followed: CAs/Liver>CAs/Muscles>CAs/Skin (in both infected and uninfected specimens). The obtained values for the content of arsenic in skin of uninfected specimens of A. alburnus were found to be more than 3 times higher than the obtained values for content of arsenic in skin of A. alburnus infected with P. laevis. In general the content of arsenic in tissues and organs of uninfected A. alburnus was higher than the content of arsenic in tissues and organs of infected with P. laevis specimens of bleak. The acanthocephalan Pomphorhynchus laevis showed 115-3042 times higher content of arsenic than its host tissues and organs. Significant negative correlation (p<0.05) was fixed for the relationship between С As/P. laevis– С As/Sediments.
Keywords: arsenic, Alburnus alburnus, Pomphorhynchus laevis, River Danube