Metal concentrations in digestive gland and mantle of Sepia officinalis from two coastal lagoons of Portugal

Concentrations of both essential (Fe, Cu, Zn) and non essential (Cd, Hg and Pb) metals were measured in the digestive gland and mantle of female cephalopods Sepia officinalis captured in two distinct lagoons in Portugal: Aveiro Lagoon, with a history of anthropogenic and industrial pollution, and Formosa Lagoon receiving urban effluents. We provide evidence for the following: (1) the digestive gland is the main target organ for both essential and non essential metals, frequently containing concentrations few orders of magnitude higher as compared to mantle; the sole exception from this was the Hg that is equally distributed in the two tissues; (2) unexpectedly, the higher levels of metals were found in animals captured in the less polluted lagoon, except for Cd whose bioavailability in Aveiro lagoon might be related to industrial sources, while the influence of Cd speciation in local pray composition should not be ruled out (3) size influenced metal concentration in different way: smaller individuals accumulated significantly more Cu, while Hg concentrations showed the opposite trend; (4) Cd is positively correlated to Zn and Cu in digestive gland of specimens collected in spring in Aveiro Lagoon, and no relationship was found in Formosa Lagoon; (5) the molar ratios Cd:Zn and Cd:Cu in digestive gland increased with body weight in specimens from Aveiro area, both ratios becoming particularly higher in older individuals. Metal-specific accumulation patterns in both mantle and digestive gland at the two sites are discussed in the light of their toxicological implications.