Prehod kovin iz tal v tkiva izbranih vrst prostoživečih živali : primer Velikega Vrha

V raziskavi smo analizirali prenos kovin iz gozdnih in travniških tal v male sesalce (rumenogrla miš, gozdna in poljska voluharica), veliko sinico in lisico, ki živijo na območju Velikega Vrha. Hkrati smo ocenili tveganje za te organizme na podlagi primerjave določenih vsebnosti v rastlinskih in živalskih tkivih s kritičnimi ter dopustnimi vsebnostmi in izračunom kvocienta tveganja (HQ) na podlagi vnosa kovin s prehrano. Izjema je bila velika sinica, ki smo jo pri izračunu HQ nadomestili s kosom, ki se pogosto prehranjuje z deževniki. Ugotovili smo, da so gozdni in travniški ekosistemi na območju Velikega Vrha, ki je bil zlasti v preteklosti izpostavljen velikim izpustom iz Termoelektrarne Šoštanj, zmerno obremenjeni s Pb (gozdna tla, živalska tkiva), Hg (gozdna tla, živalska tkiva) in Cd (travniška tla, korenine trav, detelj in zeli). Vendar tveganja za prostoživeče živali (navadna lisica, rumenogrla miš, poljska in gozdna voluharica) in deževnike nismo ugotovili, saj so bile določene vsebnosti Hg, Pb in Cd nižje od kritičnih (mali sesalci, lisica) oziroma letalnih (smrtnih) vsebnosti (deževniki). Obstaja pa verjetnost za tveganje zaradi vnosa Hg v lisico prek gozdne voluharice in zaradi vnosa Pb v kosa prek deževnikov, vendar samo v primeru, če bi ta prehranska vira sestavljala vsaj polovico diete omenjenih organizmov. We studied transfer of metals from soil to tissues of selected free-living animals: small mammals (Myodes glareolus, Microtus arvalis, Apodemus flavicollis), Parus major and red fox (Vulpes vulpes), inhabiting Veliki Vrh, Slovenia. At the same time, we assessed the risk for these organisms on the basis of comparison with metal levels in plant and animal tissues to effect concentrations for liver, critical levels of metals, defined in Slovene legislation and Hazard Quotient calculation. The exception was Parus major. This passerine bird was replaced with Turdus merula which feeds on earthworms. Our results show that meadow and forest ecosystems at Veliki Vrh, which was exposed (especially in the past) to high levels of pollutants (including metals) from thermal power plant, are moderately polluted with Pb (forest soil, animal tissues), Hg (forest soil, animal tissues) and Cd (meadow soil, roots of grass and clovers). Nevertheless, the risk for selected free-living animals was in general insignificant, since the levels of Hg, Pb and Cd were below critical (small mammals, red fox) and lethal levels (earthworms). However, there is a probability of risk due to the intake of mercury in red fox through Myodes glareolus and of Pb in Turdus merula through earthworms, if these food sources would constitute at least half of the diet of these organisms.