Maja Vihnanek Lazarus (1), Ankica Sekovanić (1), Slaven Reljić (2), Josip Kusak (2), Đuro Huber 2), Jasna Jurasović 1)
(1) Institut za medicinska istraživanja i medicinu rada u Zagrebu, (2) Veterinarski fakultet Sveučilišta u Zagrebu, E-mail: mlazarus@imi.hr
Maja Vihnanek Lazarus (Institut za medicinska istraživanja i medicinu rada u Zagrebu)
M edvjed i vuk velike su kopnene zvijeri, a njihov položaj na vrhu hranidbene mreže znači i potencijalno visok unos toksičnih metala. Glavni izvor unosa toksičnih metala je hrana: za medvjeda većinom biljnog podrijetla, a za vuka životinjskog podrijetla. Stoga sadržaj toksičnih metala u njihovim tkivima odražava razine metala u okolišu. Toksični metali kao kadmij (Cd), olovo (Pb) i živa (Hg) nakupljaju se u organizmu i iz njega slabo izlučuju. Time se, ovisno o prisutnim razinama, stvara mogućnost njihovog štetnog djelovanja na zdravlje, kako same životinje, tako i čovjeka koji meso, primjerice medvjeda, koristi kao hranu. U dostupnoj literaturi nema podataka o sustavnom praćenju toksičnih metala (niti drugih elemenata) u dinarskoj populaciji velikih zvijeri, osim izvještaja na malom broju jedinki.Ovo istraživanje imalo je za cilj izmjeriti razine Cd, Pb i Hg u tkivima (mišićju, jetri i kori bubrega) 136 smeđih medvjeda i 40 sivih vukova odstrijeljenih (prema nacionalnom Planu gospodarenja smeđim medvjedom te Planu upravljanja vukom) ili na druge načine stradalih tijekom 2009. i 2010. godine na području Gorskog kotara, Like i Dalmacije. Metali u tkivima izmjereni su tehnikom masene spektrometrije induktivno spregnute plazme (ICP-MS) nakon visokotlačne mikrovalne razgradnje.
Nađene su sljedeće razine Cd, Pb i Hg u tkivima medvjeda (medijan; μg/g mokre težine tkiva): mišić 0,008, 0,007 i 0,002, jetra 1,09, 0,496 i 0,031, bubreg 16,5, 1,12 i 0,206 te u tkivima vuka: mišić 0,0003, 0,004 i 0,003, jetra 0,055, 0,107 i 0,016, bubreg 0,182, 0,088 i 0,034. Kod vuka su izmjerene niže koncentracije svih metala nego kod medvjeda, s najizraženijom razlikom u razinama Cd, što je posljedica razlike u količini pojedene hrane te općenito prehrambenim navikama. Kod medvjeda, ženke su imale oko dva puta više razine Cd i Hg u tkivima od mužjaka, dok kod vukova nisu primijećene spolne razlike u razinama metala. Povišene razine Cd u skupini starih medvjeda (stariji od 3 godine) i vukova (stariji od 2 godine) u odnosu na mlade (p<0,05) upućuju na nakupljanje Cd u svim istraživanim tkivima. S obzirom na zakonom propisane najviše dopuštene količine metala u mesu za konzumaciju, meso medvjeda sigurno je za ljudsku upotrebu, dok se iznutrice preporuča izbjegavati, prvenstveno zbog povišenih razina Cd.
← PARAZITARNE ZOONOZE I TEŠKI METALI U KOPNENIH I MORSKIH PREDATORA
Toxic metals in Croatian large terrestrial carnivores
Maja Vihnanek Lazarus, Ankica Sekovanić, Slaven Reljić, Josip Kusak, Đuro Huber, Jasna Jurasović
E-mail: mlazarus@imi.hr
The bear and the wolf are large terrestrial carnivores whose position in the food web implies a potentially high intake of toxic metals. The main source for this intake is food: for bears, food mostly originates from plants; while for wolves, it mainly originates from the meat of other animals. Therefore, the toxic metal content in their tissue reflects the toxic metal levels in the environment. Toxic metals such as cadmium (Cd), lead (Pb), and mercury (Hg), accumulate in the organism and are excreted very slowly. This, depending on the levels, enables these metals to negatively impact the health of animals and the people who eat their meat (for instance, bear meat). There are no data in the available literature on the monitoring of toxic metals (or any other element) in the Dinaric population of large carnivores, except for a limited report on few individuals.
This investigation was aimed at measuring the Cd, Pb, and Hg levels in the tissue (muscles, liver, and renal cortex) of 136 brown bears and 40 grey wolves hunted (according to the Croatian Brown Bear Management Plan and Croatian Wolf Management Plan) or killed otherwise in the Croatian regions of Gorski kotar, Lika, and Dalmacija during 2009 and 2010. Metal levels in the tissues were measured by inductively coupled plasma mass spectrometry (ICP-MS) after high-pressure microwave decomposition.
The following levels of Cd, Pb, and Hg were found in the bear tissue (median; μg/g wet tissue weight): muscle 0.008, 0.007, and 0.002, liver 1.09, 0.496 and 0.031, kidney 16.5, 1.12, and 0.206; while wolf tissues had the following levels: muscle 0.0003, 0.004, and 0.003, liver 0.055, 0.107, and 0.016, kidney 0.182, 0.088, and 0.034. Wolves exhibited somewhat lower metal concentrations than
bears and the highest discrepancy was found in the Cd levels, which is the result of the differences in the amount of food consumed and general dietary habits. In bears, females had approx. twice as high levels of Cd and Hg than males, whereas wolves displayed no gender differences. Increased Cd levels in a group of older bears (older than 3 years) and wolves (older than 2 years) when compared to younger individuals (p<0.05) indicate an accumulation of Cd in all of the investigated tissues. Considering the official highest permitted values for metal levels in meat, bear meat can be declared safe for human consumption, with the exception of bear offal, which contains higher levels of Cd.
