Metal interactions within and between tissues of nestling rooks Corvus frugilegus

We analyzed interactions of concentrations of 11 essential and nonessential elements, including toxic metals within and between internal organs (liver, kidney and lung), muscles and bones of nestling rooks Corvus frugilegus with acute cadmium contamination and elevated level of lead. The number of statistically significant (P ≤ 0.05) metal-metal relationships (positive/negative) within particular tissues was the highest in the kidney (7/6), following in the bone (9/2), liver (6/4), lung (5/2) and muscle (5/2). We found eight significant interactions of lead with other metals, and only two of cadmium (only with lead and cobalt, which probably mirrored a greater ability of lead (than in the case of cadmium) to functional and kinetic interaction with other metals, and/or inhibiting effect of lead or cadmium in co-accumulation. Furthermore, a positive relationship between concentration of cadmium and lead in the kidney could hint at the key importance of this organ in detoxification of both toxic metals. Analyses of relationships of individual metals between examined tissues show only positive results in the case of copper (n = 8), following potassium (n = 3), zinc and iron (in both cases n = 2) and a single ones for calcium and magnesium. We concluded that the lack of significant relationships of individual toxic metals (cadmium or lead) between analyzed tissues could result from high levels of these metals, which destroyed detoxifying capacity of kidney, and ultimately enabled a rapid bioaccumulation of these inorganic contaminations in all tissues of examined nestlings. An explanation of concentration of toxic metals in tissues of animals, especially in the case of their high level, require an identification of the actual level of essential elements associated with physiological status of organism.