Mercury in the tissues of five cephalopods species: First data on the nervous system

Mercury (Hg), one of the elements most toxic to biota, accumulates within organisms throughout their lifespan and biomagnifies along trophic chain. Due key role in marine systems, cephalopods constitute a major vector Hg predators. Further, they grow rapidly display complex behaviours, which can be altered by neurotoxic Hg. This study investigated concentrations 81 cephalopod specimens sampled Bay Biscay, belonged five species: Eledone cirrhosa, Sepia officinalis, Loligo vulgaris, Todaropsis eblanae Illex coindetii. were measured digestive gland, mantle muscle optic lobes brain. The gland tissues with concentrated among all species considered (up 1.50 ?g.g?1 dw), except E. cirrhosa. benthic had 1.3-fold higher brain 1.89 dw) than mantle, while other 2-fold lower mantle. Brain-Hg predicted from muscle-Hg for given species, facilitates assessment toxicokinetics cephalopods. In contaminated cirrhosa individual, chemical form its lobes, was determined using High energy-Resolution X-ray Absorption Near Edge Structure (HR XANES) spectroscopy. 33 ± 11% total inorganic speciated as dicysteinate (Hg(Cys)2), suggested that demethylation dietary MeHg occurs this organ. All found is methylated bound cysteinyl group (MeHgCys complex), implies distributed these via bloodstream. These results raised questions regarding interspecific differences observed possible effect on functional plasticity behaviour.