Essential and Nonessential Elements in Nestling Rooks Corvus frugilegus from Eastern Poland with a Special Emphasis on Their High Cadmium Contamination

Abstract

Concentration of minerals (sodium, potassium, calcium [Ca], magnesium, iron [Fe], copper, zinc [Zn], manganese [Mn], and cobalt) as well as toxic metals (cadmium [Cd], lead [Pb]) were determined in five tissues (liver, lung, kidney, muscle, and bone) of nestling rooks (Corvus frugilegus; 1 to 13 days old) found dead in seven breeding colonies in eastern Poland. Cd concentration in all analyzed tissues was in the narrow range of 17.0-17.2 mg/kg dry weight (dw) Cd, which in the light of the literature data indicates acute contamination by this toxic metal. Similarly, we found increased levels of Pb, which in all tissues ranged between 5.0 and 6.2 mg/kg dw. Results of multivariate general linear model (GLM) testing of the effect of three variables (tissue type, colony, and nestling age) on tissue concentrations of various metals showed significance for Fe, Cu, Zn, and Mn. Only concentrations of Ca, Fe, and Zn differed significantly between the analyzed tissues. GLM analysis did not show any statistically significant differences in tissue levels of minerals and both toxic metals among examined rookeries, which indicates the widespread presence of nonpoint Cd and Pb pollution linked to agricultural activity and similar levels of these inorganic contaminants on crop fields (feeding grounds) around breeding colonies. We concluded that high levels of both toxic metals, Cd and Pb, probably resulting from the diet of nestling rooks, are based mainly on a diet of ground-dwelling beetles gathered on crop fields.

Tissue Distribution of Heavy Metals in Heron and Egret Chicks from Pyeongtaek, Korea

“…The mean concentrations of cadmium in bones of four species of heron and egret chicks in this study ranged from 0.93 to 3.40 lg/g dw. These concentrations were far lower than those of Rook nestlings (Orłowski et al 2012), but were much higher than those of two passerine species (Deng et al 2007). …”

“…Chronic exposure has been reported in other birds (Migula et al 2000;Horai et al 2007;Deng et al 2007;Zaccaroni et al 2008;Włostowski et al 2010;Cui et al 2013). However, Grey Heron chicks and Rook nestlings had similar cadmium concentrations in livers and kidneys (Orłowski et al 2012). …”

“…And, lead concentrations in kidney were significantly higher than in other tissues of four species of heron and egret chicks. Difference in lead concentrations among species have been reported for various birds from the same colony (Deng et al 2007;Horai et al 2007;Kojadinovic et al 2007;Kim et al 2010;Włostowski et al Deng et al 2007;Orłowski et al 2012). However, liver and kidney concentrations were lower than reported in Little Egret chicks .…”

“…Mean concentrations of cadmium in the kidney of Grey Heron chicks from the present study were lower than those of Grey Herons (Horai et al 2007) and Intermediate Egrets had similar kidney concentrations (this study; Horai et al 2007). Observed cadmium concentrations in livers and kidneys of herons and egrets were lower than those of Rook nestlings (Orłowski et al 2012). The mean concentrations of cadmium in bones of four species of heron and egret chicks in this study ranged from 0.93 to 3.40 lg/g dw.…”

“…The cadmium concentration in the sediment of foraging site was 0.07 lg/g dw. Species-and tissue-specific accumulations have been reported various birds; passerines (Deng et al 2007), three seabird species (Kojadinovic et al 2007), heron and egret adults (Horai et al 2007) and chicks and Magpies (Pica pica) (Włostowski et al 2010) and Rook (Corvus frugilegus) nestlings (Orłowski et al 2012). In general, cadmium is predominantly accumulated in kidneys of birds and the kidney for cadmium is considered a longterm storage tissue.…”