Small mammals as biomonitors of metal pollution: a case study in Slovenia

Abstract

The transfer of lead, cadmium, zinc, mercury, copper and molybdenum from soil to the tissues of small mammals inhabiting differently polluted areas in Slovenia was investigated. Metals were determined in soil samples and in the livers of 139 individuals of five small mammal species, collected in 2012 in the vicinity of a former lead smelter, the largest Slovenian thermal power plant, along a main road and in a control area. The area in the vicinity of former lead smelter differs considerably from other study areas. The soil from that area is heavily polluted with Pb and Cd. The mean metal concentrations in the liver, irrespective of species, varied in the following ranges-Pb: 0.40-7.40 mg/kg fw and Cd: 0.27-135 mg/kg fw and reached effect concentrations at which toxic effects can be expected in a significant proportion of the livers of the small mammal specimens (Pb 40 %, Cd 67 %). These findings indicate that the majority of small mammals trapped in the area of the former lead smelter are at risk of toxic effects due to the very high bioaccumulation of Pb and Cd in the organism. On the contrary, Pd and Cd concentrations in the livers of small mammals sampled in the vicinity of the thermal power plant and along the main road were comparable with reference values and considerably lower than effect concentrations. Additionally, the study suggests that Apodemus flavicollis and Myodes glareolus are very suitable biomonitors of metal pollution.

Lead Levels in the Bones of Small Rodents from Alpine and Subalpine Habitats in the Tian-Shan Mountains, Kyrgyzstan

“…It is generally known that small terrestrial mammals are the most suitable bio-monitors of heavy-metal pollution to apply findings to humans [15]. In Tian-Shan, the silver mountain vole (Alticola argentatus) and narrow-headed vole (Microtus gregalis) are some of the most widespread rodents.…”

Concentration of Mercury in the Livers of Small Terrestrial Rodents from Rural Areas in Poland

“…The mean concentration of Hg found in the livers of all species of rodents from the most polluted DAB site (15 µg/kg of wet weight) was one-seventh of the level of Hg found in the livers of A. flavicollis from areas polluted by lead smelting in Slovenia, but threefold higher than that observed in the same species captured in the area contaminated by power plant emissions in that country [34]. Much higher levels than ours were found in Microtus guentheri from the marble mining area in Turkey [35], in M. glareolus from the zone around a chlor-alkali plant in Great Britain [36], and in Apodemus sylvaticus from different polluted and unpolluted areas in Galicia in northern Spain [37].…”

Heavy Metal Pollution as a Biodiversity Threat

“…Some examples of wild vertebrate species used in ecotoxicological studies are: Brown bears (Ursus arctos), Gray wolfs (Canis lupus), Eurasian badgers (Meles meles) and Pine martens (Martes martes) [27], bank vole (Clethrionomys glareolus), yellow-necked mouse (Apodemus flavicollis) [28][29][30], wood mice (Apodemus sylvaticus) [31,32], tuco-tuco (Ctenomys torquatus) [33], greater white-toothed (Crosidura russula) [34], Peromyscus melanophrys, pygmy mice (Baiomys musculus) [7,35].…”