Partitioning of Fe, Cu, Zn, Cd, and Pb concentrations among eleven tissues of Octopus vulgaris from the Portuguese coast

Abstract

Levels of Fe, Cu, Zn, Cd, and Pb were determined in digestive gland, posterior salivary glands, kidneys, gills, gonads, branchial hearts, ink sac, stomach, skin, mantle, and arm of 13 common octopuses, Octopus vulgaris, collected in November 2002 at Matosinhos (northwest coast of Portugal). No significant (P > 0.05) differences were found between metal concentrations and size/weight, sex, and maturity stage. Median levels found in digestive gland were one order of magnitude above those in all remaining analyzed parts (Cd and Pb), and in all tissues except branchial heart (Fe); posterior salivary glands, gills, mantle, and arm (Zn); and arm (Cu). Iron was significantly higher in digestive gland and branchial heart; Cu was lower in gonads, mantle, and arm; Zn was higher in digestive gland and lower in mantle and arm; Cd was higher in digestive gland, ink sac, and kidneys; and Pb was higher in digestive gland. Strong Pb-Fe, Cd-Fe, and Cu-Zn correlations (r > 0.700) were obtained in digestive gland, salivary glands, ink sac, and stomach. The different metal concentrations in the 11 tissues/organs of octopus are apparently a consequence of the role of metals in metabolic functions (e.g., gonads, ink sac, kidneys, gills, and salivary glands), although non-essential elements (Cd and Pb) in digestive gland, branchial hearts, kidneys, and ink sac may be linked to specific ligands or excretory/detoxification mechanisms.