Element concentrations in a unionid mussel (anodonta woodiana') at different life stages

The 'background' levels of 18 elements (Na, Mg, Al, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd, and Tl) were measured in unionid mussels (Anodonta woodiana) at three different life stages (i.e., glochidia-whole body, juveniles and gravid adults-whole soft tissue). Field-collected adult mussels were cultured in experiment ponds for one year before used for tissue collection. Matured glochidia were collected from the adults for the element measurement and the culture of the juvenile mussels. The results of principal component analysis of the element concentrations indicated a significant life stage-dependent variation of element accumulation. The concentrations of Ca, Fe, Zn, As, Cd, Ni, and Mn were generally higher in the adult mussels than those in the juvenile mussels. However, several elements (e.g., Co, Cu, Mo, Ag) were significantly higher in the juveniles than those in the adults. Manganese appeared to be accumulated at high concentration in all three life stages. The background residue concentrations of heavy metals and toxic elements in the artificially produced mussels were very low, while that contaminated As in gravid adults was still obviously high, suggesting that the formers will be potentially more suitable to be used as the bioindicators for the corresponding elements by wild transplantation or laboratory exposure study rather than the gravid adults.