Mercury Content in Organs and Tissues of Indigenous (Vulpes vulpes L.) and Invasive (Nyctereutes procyonoides Gray.) Species of Canids from Areas Near Cherepovets (North-Western Industrial Region, Russia).

Trophic and spatial components of ecological niches of two canids native Vulpes vulpes and introduced Nyctereutes procyonoides are overlapping partially in the studied region. Maximum concentrations of mercury in predatory mammals of Canidae family from surroundings of Cherepovets have been determined in liver and kidneys (over 0.50 mg/kg wet weight), with minimal concentrations in brain (<0.2 mg/kg wet weight). The amount of mercury in the same organs of the red fox and raccoon dog is not significantly different. These levels of mercury content are noticeably higher than those in the predators of Canidae family that inhabit territories of Europe lacking the local sources of mercury. At the same time, absolute values of metal quantity are commensurable with the levels registered in predators from the mercury polluted regions of Spain and Poland.