Nina Bilandžić (1), Maja Đokić (1), Marija Sedak (1), Martina Đuras (2), Tomislav Gomerčić (2)
(1) Hrvatski veterinarski institut u Zagrebu
(2) Veterinarski fakultet Sveučilišta u Zagrebu
E-mail: bilandzic@veinst.hr
Marija Sedak
(Hrvatski veterinarski institut)
T oksični elementi: arsen (As), kadmij (Cd), olovo (Pb) i živa (Hg) široko su rasprostranjeni u okolišu i ulaze u morske sisavce na više različitih načina: putem atmosfere kroz pluća, apsorpcijom kroz kožu, preko placente prije poroda, mlijekom za vrijeme laktacije, gutanjem morske vode i, najviše, uzimanjem hrane. Zagađivanjem mora ti elementi mogu doseći visoke koncentracije u organima i tkivima morskih sisavaca kao vršnih predatora. Kitove se općenito smatra kao poveznike okolišnih zagađivala poput metala zbog njihovog dugog života i visokog položaja u prehrambenoj mreži.
Raspored toksičnih elementa u različitim organima i tkivima dupina uvelike je istraživan posljednjih desetljeća. Pokazalo se da je raznolikost razina tragova metalnih elemenata među vrstama kitova i u morskim staništima posljedica prehrambenih izvora, fiziološkog stanja jedinki i toksikološke dinamike pojedinog metala. Budući da su i Cd i Hg egzogeni i štetni elementi koji se kumuliraju tijekom rasta, visoke koncentracije u jetri su povezane s ulogom jetre u uklanjanju tih elemenata iz krvotoka demetilacijom i bio-transformacijom.
U Jadranskom moru ili u Mediteranskom bazenu stalno je prisutno nekoliko vrsta kitova uključujući dobrog (Tursiops truncatus), plavobijelog (Stenella coeruleoalba) i glavatog dupina (Grampus griseus). Dobri dupin je jedina vrsta stalno prisutna u regiji. Plavobijeli dupini povremeno dolaze do sjevernog Jadrana i duž obala Hrvatske. Nalazi glavatog dupina upućuju na zaključak da se on povremeno pojavljivao u Jadranu. Niske razine toksičnih metala su utvrđene u dobrih, plavobijelih i glavatih dupina nađenih duž Jadranske obale.
Istraženi su odnosi njihovih koncentracija u različitih vrsta i različitih tkiva, te uspoređeni s objavljenim studijama o dupinima iz Mediteranskog i Jadranskog mora.
← PARAZITARNE ZOONOZE I TEŠKI METALI U KOPNENIH I MORSKIH PREDATORA
Toxic element concentrations in three dolphins species stranded in Eastern Adriatic Sea
Nina Bilandžić, Maja Đokić, Marija Sedak, Martina Đuras, Tomislav Gomerčić
E-mail: bilandzic@veinst.hr
The toxic elements, arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) are widely dispersed in the environment and enter marine mammals through several different routes: atmospheric uptake via the lungs, absorption through the skin, across the placenta before birth, through milk lactation, and ingestion of sea water; however, the major route of ingestion is diet. The result of marine pollution is that these elements can reach high concentrations in the organs and tissues of marine mammals as top predators. Cetaceans are generally considered integrators of environmental pollutants such as metals due to their longevity and their elevated position in marine food webs.
In recent decades, considerable research has looked at the distribution of toxic elements in different organs and tissues of dolphins. The variability in trace metal levels among cetacean species and marine habitats was shown to be due to food sources, the physiological state of the individual and the toxicological dynamics of the specific metal. As both Cd and Hg are exogenous and harmful
elements that accumulate during growth, high hepatic concentrations of these elements are related to the role played by the liver in terms of removing of these elements from the bloodstream, demethylation and bio-transformation.
Several cetacean species, including the bottlenose (Tursiops truncatus), striped (Stenella coeruleoalba) and Risso’s (Grampus griseus) dolphins, have been reported in the Adriatic Sea and are regularly present in the Mediterranean basin. The bottlenose dolphin is the only cetacean species that can be considered to occur regularly in the region. Striped dolphins are rare and may occasionally wander into the northern Adriatic and along the entire Croatian coastline. Surveillance of Risso’s dolphin suggested that it has been always accidental and that the species presently occurs occasionally in the Adriatic Sea. Trace levels of toxic metals were determined in bottlenose, striped and Risso’s dolphins accidentally caught or found dead along the Adriatic coastline.
The relationships between their concentrations in different tissues and species were examined and compared to studies reported in the literature on dolphins from the Mediterranean and Adriatic Seas.
