First Systematic Voltammetric Measurements of Cd, Pb, and Cu in Hydrofluoric Acid-Dissolved Siliceous Spicules of Marine Sponges: Application to Antarctic Specimens

摘要

Ultrasensitive Square Wave Anodic Stripping Voltammetry is used for the first time for the systematic determination of Cd, Pb, and Cu in siliceous spicules of marine sponges; the procedure is performed directly in hydrofluoric acid solution, according to a procedure previously established in our laboratory, with the aim of demonstrating the feasibility of such measurements and to improve knowledge of heavy metal distribution in Porifera. The following Demospongiae species are considered: Sphaerotylus antarcticus, Haliclona sp., Kirkpatrickia coulmani, and Inflatella belli from the Ross Sea, Antarctica, and Petrosia ficiformis from the Mediterranean Sea, Italy. The method shows a good accuracy; the analytical variability is approximately ±10% for all the metals studied and for all the measurements performed, showing a good repeatability of the method in consideration of low metal concentrations (order of tenths of μg g -1 dry weight, i.e., of hundreds of ng L ~(-1) in the HF solution). In particular, the concentrations of heavy metals in the body of the sponge vary in the range 0.038-0.93 μg g ~(-1) dry weight (d.w.) for Cd, 0.024-0.52 μg g ~(-1) d.w. for Pb, and 0.32-1.3 μg g ~(-1) d.w. for Cu. Similar ranges of concentration were recorded in the oscula of S. antarcticus and I. belli. Heavy metal concentration in the spicules can vary within and between specimens and, in particular, siliceous spicules of Antarctic sponges show higher concentrations of Cd and Pb and lower concentrations of Cu than those from the Mediterranean.