Development and comparison of methods for measuring heavy metal concentrations in coral tissues

Two procedures for measuring cadmium, lead, copper, zinc, nickel, and chrom ium concentrations in scleractinian coral tissues were compared. The proced ures were: (a) physically separating tissues from skeleton by water-pik, us ing buffered washings designed to prevent loss of labile metals from tissue proteins, and (b) chemically extracting tissues from skeletons using hydro gen peroxide, pH adjusted to 8.2 to prevent dissolution of aragonite coral skeletons. The water-pik extraction procedure had fewer detection limits, a nd produced consistently higher concentrations of all six metals, than the hydrogen peroxide extraction procedure. Although not proven, these procedur al differences may result from consistent overestimations in biomass of che mically extracted tissues, or from interactions of tissue-metals with coral skeletons during sample preparation. (C) 2000 Elsevier Science B.V. All ri ghts reserved.