Essential and nonessential elements in the red-crowned crane Grus japonensis of Zhalong Wetland, northeastern China

The concentrations of four essential (Ca, Mg, Zn, and Cu) and two nonessential elements (Pb and Cd) in feathers and kidneys, livers, gut walls, and muscles of eight carcasses of migratory red-crowned cranes (Grus japonensis) from Zhalong Wetland, northeastern China, were examined. The concentrations of Cd in the feathers were between 0.4 mg kg(-1) dry weight (dw) and 3.1 mg kg(-1) dw, in the livers between 0.4 and 4.4 mg kg(-1) dw, the maximum of which exceeded a level considered to be environmental exposure risk (i.e., 3 mg kg(-1) dw in the liver or kidney). High Pb levels (0.4-3.2 mg kg(-1) dw, with an average of 1.8 mg kg(-1)) were also detected in livers, which exceeded a level considered toxicosis in birds (1.7 mg kg(-1) dw). Pb and Cd had the highest scores in principal component analysis. Relatively high Pb and Cd concentrations in the migratory cranes were thought to be associated with their habitat and prey.