Lead accumulation in rats: The effect of the presence of a rat tapeworm and the different forms of metal in the host diet

The main aim of this study was to determine the possibility of using a rat tapeworm, Hymenolepis diminuta as a bioindicatortor of organic and inorganic lead forms. The bioaccumulation of cadmium and zinc were determined as well. The influence of this parasite was determined regarding to the concentration of elements in the tissues of a definitive host, the white rat (Rattus norvegicus). Male Wistar rats were experimentally infected with H. diminuta and exposed to two different forms of lead (lead nitrate and lead bounded in Pistia stratiotes) for six weeks via oral exposure of the host. After the exposure period, the element levels were determined in the rat (liver, kidney, spleen, testes, muscles, bones and intestine) and tapeworm tissues with ICP-OES. Tapeworms in Pistia group accumulated 135.2, 98.4, 83.2, 45.1, 38.6 and 25.8 times more Pb concentrations than their hosts muscle, testes, intestine, liver, kidney and spleen, respectively. In Nitrate group, tapeworms accumulated from 2.7 (spleen) to 9.2, 9.5 and 9.6 (testes, liver and muscle, respectively) times higher concentrations than their hosts. Zn was accumulated up to 4.2 times higher in tissues of tapeworm. Cd levels were detected only in tissues of tapeworm, not in their host tissues. Pb concentrations were up to 12.9 times higher in tissues of non-parasitized than in parasitized rats. Lead from lead nitrate accumulated in higher levels than lead from Pistia stratiotes. This study confirmed the possibility of using H. diminuta as a Pb, Cd and Zn bioindicator of risk element pollution in the environment.